Spiny lobster management

SPINY LOBSTERS: FISHERIES AND CULTURE

SPINY LOBSTERS: FISHERIES AND CULTURE SECOND EDITION EDITED BY

B.F. PHILLIPS Curtin University of Technology, P . O . Box U1987, Perth, Western Australia 6845, Australia

J. KITTAKA Research Institute for Marine Biological Science, Research Institutes for Science and Technology, The Science University of Tokyo, Nemuro City, Fisheries Research Institute, Hokkaido 087-0166, Japan

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A catalogue record for this title is available from the British Library ISBN 0-85238-264-2 Library of Congress Cataloging-in-Publication Data Spiny lobsters : fisheries and culture / edited by B.F. Phillips and J. Kittaka. - 2nd ed. p. cm. Rev. ed. of: Spiny lobster management. 1994. Includes bibliographical references. ISBN 0-85238-264-2 (hardcover) 1. Lobster fisheries - Management. 2. Spiny lobsters. I. Phillips, Bruce F. 11. Kittaka, J. 111. Spiny lobster management. SH380 .S65 2000 639'.54dc2 1. 00-02937 1 For further information on Fishing News Books, visit our website: http://www.blacksci.co.uk/fnb/

Contents Preface

ix

B.F. PHILLIPS AND J. KITTAKA

List of Contributors Introduction: Ecology and Fishery Biology of Spiny Lobsters

xi 1

R.N. LIPCIUS and D.B. EGGLESTON

PART 1: FISHERIES: METHODS, MANAGEMENT A N D STATUS 1

The Status of Australia’s Rock Lobster Fisheries

43 45

B.F. PHILLIPS, C.F. CHUBB and R. MELVILLE-SMITH

2

New Zealand’s Rock Lobster Fisheries

78

J.D. BOOTH

3

Fisheries for Spiny Lobsters in the Tropical Indo-West Pacific

90

J.L. MUNRO

4

The Lobster Fishery in the North-western Hawaiian Islands

98

J.J. POLOVINA

5

The Commercial Fisheries for Jasus and Palinurus Species in the South-east Atlantic and South-west Indian Oceans

105

D.E. POLLOCK, A.C. COCKCROFT, J.C. GROENEVELD and D.S. SCHOEMAN

6

The State of the Lobster Fishery in North-east Brazil

121

A.A. FONTELES-FILIIO

7

The Cuban Spiny Lobster Fishery

135

J.A. BAISRE

8

The Atlantic Spiny Lobster Resources of Central America

153

N.M. EHRHARDT

9

The Spiny Lobster Fisheries in Mexico

169

P. BRIONES-FOURZAN and E. LOZANO-ALVAREZ

10

Status of the Fishery for Panulirus argus in Florida

189

J.H. HUNT

11

The French Fisheries for the European Spiny Lobster Palinurus elephas

200

H.J. CECCALDI and D. LATROUITE

V

vi

Contents

12

The Galapagos Spiny Lobster Fishery

210

R.H. BUSTAMANTE, G.K. RECK, B.I. RUTTENBERG and J . POLOVINA

13

The Spiny Lobster Fishery in Japan and Restocking

22 1

M. NONAKA, H. FUSHIMI and T. YAMAKAWA

PART 2: RESEARCH FOR MANAGEMENT: CASE STUDIES 14

Reproductive Biology: Issues for Management

243 245

C.F. CHUBB

15

Puerulus and Juvenile Ecology M.J. BUTLER IV and

16

276

W.F.HERRNKIND

Stock Identity of the Red (Jasus edwardsii) and Green (Jasus verreauxi) 302 Rock Lobsters Inferred from Mitochondria1 DNA Analysis J.R. OVENDEN and D.J. BRASHER

17

Spiny Lobster Catches and the Ocean Environment

32 1

B.F. PHILLIPS, A.F. PEARCE, R. LITCHFIELD and S. GUZMAN DEL PRO0

18

Measurement of Catch and Fishing Effort in the Western Rock Lobster Fishery

334

N. CAPUTI, C.F. CHUBB, N.G. HALL and R.S. BROWN

19

Predicting the Catch of Spiny Lobster Fisheries

357

B.F. PHILLIPS, R. CRUZ, N. CAPUTI and R.S. BROWN

20

Bioeconomic Modelling of the New Zealand Fishery for Red Rock Lobsters (Jams edwardsii)

376

P.A. BREEN, D.J. GILBERT and K. CHANT

21

Modelling for Management: The Western Rock Lobster Fishery

386

N.G. HALL and R.S. BROWN

22

The Artificial Shelters (Pesqueros) used for the Spiny Lobster (Panulirus argus) Fisheries in Cuba

400

R. CRUZ and B.F. PHILLIPS

23

The Use of Artificial Shelters (Casitas) in Research and Harvesting of Caribbean Spiny Lobsters in Mexico

420

P. BRIONES-FOURZAN, E. LOZANO-ALVAREZ and D.B. EGGLESTON

24

Recreational Spiny Lobster Fisheries - Research and Management

447

R. MELVILLE-SMITH, B.F. PHILLIPS and J. PENN

PART 3: AQUACULTURE AND MARKETING 25

Prospectus for Aquaculture J. KITTAKA and J.D. BOOTH

463 465

Contents 26

Maturation

vii 474

K. NAKAMURA

27

Breeding

48 5

A.B. MACDlARMlD and J. KITTAKA

28

Culture of Larval Spiny Lobsters

508

J. KITTAKA

29

Water Quality and Microflora in the Culture Water of Phyllosomas

533

M.A. IGARASHI and J . KITTAKA

30

Spiny Lobster Growout

556

J.D. BOOTH and J. KITTAKA

31

Diseases of Spiny Lobsters

586

L.H. EVANS, J.B. JONES and J.A. BROCK

32

Functional Morphology of the Digestive System

60 1

S. MIKAMI and F. TAKASHIMA

33

Nutrition and Food

61 1

A. KANAZAWA

34

Colour and Taste

625

S. KONOSU and K. YAMAGUCHI

35

Shipping

633

H. SUGITA and Y. DEGUCHI

36

Export Marketing of Australian and New Zealand Spiny Lobsters

64 1

R.N. STEVENS and D . SYKES

37

Marketing and Distribution in Japan

6 54

M. TSURUTA and J. KITTAKA

PART 4: PERSPECTIVES 38

Perspectives

665 667

B.F. PHILLIPS

Index

673

Preface Spiny lobsters, or rock lobsters as they are also known, are among the world’s most valuable and highly prized seafood. They are featured on menus from Japan to Europe. In addition, their size, abundance and position in the food web make them important ecologically. Fishing pressure on spiny lobster populations can be intense, leading to a need for wise management decisions. In this book, the management of spiny lobsters is addressed from biological and economic perspectives. Spiny lobsters are captured and marketed in over 90 countries. The world catch is currently in excess of 77 thousand metric tonnes (t) per year, with a landed value of approximately US $500 million. The principal producing countries are Australia, New Zealand, South Africa, Cuba, Brazil, Mexico and the USA, with over 70% of the catch coming from the Caribbean and south-east Atlantic region and the eastern Indian Ocean. The product is usually marketed frozen but the highest prices are obtained for live spiny lobsters, for which the Japanese are willing to pay more than US $100 per kilogram. Most spiny lobsters inhabit coral or rocky areas in shallow waters. This, combined with their large size and frequently dense populations, makes them important ecologically and relatively easy to study. Over the past 20 years we have learned a great deal about patterns of reproduction, migration, population growth and response to human exploitation in a number of species. In particular, an excellent picture of the ecology and fisheries biology of the Western Australian spiny lobster has been drawn, and research in Florida, Cuba, New Zealand and South Africa has begun to show similar patterns. Demand for spiny lobsters has escalated over the past two decades, spurring the need both for better management and for research on which to base that management. In Cuba, for instance, the catch rose from 500 t in 1965 to 13 500 t in 1985, but now oscillates between 8000 and 10 000 t. In South Africa, once the largest producer of spiny lobsters world-wide, the catch has dropped dramatically in recent years. In Western Australia, very strict management regulations and enforcement since virtually the beginning of the fishery has prevented overexploitation on the scale seen in other fisheries. A new and exciting development is now on the horizon and spiny lobster aquaculture appears to be a real possibility. Culture of the clawed North American lobster has been proposed and attempted for some 50 years, but is still not an economic reality. This, and the long larval life of spiny lobsters, has created an air of pessimism, resulting in few serious attempts to culture spiny lobster. However, recent developments in Japan and New Zealand have demonstrated the complete culture through the larval and puerulus stages. Australia is now investing in research into spiny lobser aquaculture and, although there continue to be problems to be ix

overcome, it may be only a few years before the major source of spiny lobsters is from aquaculture. We open the book with a brief review, by way of an introduction to spiny lobsters: general biology, types, distribution, fishing techniques, etc. Status reports of the major fisheries then follow, but the emphasis is on the latest management strategies, developments in aquaculture, marketing and economics. A special feature of the book is its reviews of the research activities and the marketing process in Japan. In the present book, we asked the authors to examine what was new and directly related to management, culture etc., and not to re-do the comprehensive Biology and Management of Lobsters (Cobb & Phillips, 1980, Academic Press). Thus, for instance, a chapter in this book on ‘Reproduction’ focuses only on those aspects of major importance to fisheries managers, and attempts to show how they are important. In the section on aquaculture, several authors examine maturation and breeding from that viewpoint. The authors of the book come from many parts of the world, and the varying approaches to science and writing styles are clear. The industry, the management and the science all have global connections. This is the first book that tries to bring the varied approaches together. We thank the authors for their efforts and hope that the communication fostered by their efforts will be rewarding. The book was first published in 1994 under the title of Spiny Lobster Management. It completely sold out, and there were demands for additional copies. Instead of simply reprinting the 1994 book, it was decided to revise all the chapters for a new edition. We have also taken the opportunity to include a chapter on recreational fishing and to add additional material on aquaculture, including the chapter on water quality and microflora (Chapter 29). The chapters on marketing have been replaced with new chapters which we feel are of greater relevance. In revising the chapters that we wrote as individuals, and in examining the chapters revised by the other authors, we were continually amazed at the changes that have occurred in the past 5 years. This completely vindicates the decision to revise all the chapters for the new edition and indicates the necessity for a ‘new’ book.

Acknowledgements Many people contributed to the development and production of this book. They are not acknowledged individually because of space availability, but all the authors wish to thank the many colleagues who assisted them with their contributions.

B.F. Phillips J. Kittaka

List of Contributors

J.A. Baisre Ministerio de la Industria Pesquera Barlovento Santa Fe 19 500 La Habana Cuba

J.D. Booth National Institute of Water and Atmospheric Research P.O. Box 14-901, Kilbirnie Wellington 6003 New Zealand D.J. Brasher 53c Devonshire Drive London SE 10 8 5 2 UK P.A. Breen National Institute of Water and Atmospheric Research P.O. Box 14-901, Kilbirnie Wellington 6003 New Zealand P. Briones-Fourzan Universidad Nacionai Autonoma de Mexico Instituto de Ciencias del Mar y Limnologia Unidad Academica Puerto Morelos Ap. Postal 1152 Cancun QR 77500 Mexico J. A. Brock Aquaculture Development Program Department of Agriculture Room 400 1177 Alakea Street Honolulu, Hawaii 968 13 USA

xi

xii

List of Coiztr.ihzrtor.v

R.S. Brown Bernard Bowen Fisheries Research Institute Western Australian Marine Research Laboratories P.O. Box 20 North Beach Western Australia 6020 Australia

R.H. Bustamante Charles Darwin Research Station Galipagos Islands Ecuador

M.J. Butler IV Department of Biological Sciences Old Dominion University Norfolk, VA 23529-0266 USA N. Caputi Bernard Bowen Fisheries Research Institute Western Australian Marine Research Laboratories P.O. Box 20 North Beach Western Australia 6020 Australia H.J. Ceccaldi Ecole Pratique des Hautes Etudes Centre d’Etudes des Ressources Animales Marines (CERAM) FacultC des Sciences et Technique de Saint-Jer6me Ave. Escadrille Normandie-Niemen F-13397 Marseille Cedex 20 France

K. Chant New Zealand Ministry of Economic Development P.O. Box 1473 Wellington 6001 New Zealand

List of Contributors

C.F. Chubb Bernard Bowen Fisheries Research Institute Western Australian Marine Research Laboratories P.O. Box 20 North Beach Western Australia 6020 Australia A.C. Cockcroft Marine and Coastal Management Department of Environmental Affairs and Tourism P. Bag X2 Rogge Bay 8012 South Africa

R. Cruz Centro de Investigaciones Marinas Calle 16 144 entre Ave. lera y 3era Miramar Playa Ciudad de la Habana Cuba Y. Deguchi Department of Marine Science and Resources Nihon University Fujisawa Kanagawa 252-8510 Japan D. Eggleston Department of Marine, Earth and Atmospheric Sciences North Carolina State University Raleigh, NC 27695-8208 USA N.M. Ehrhardt Division of Marine Biology and Fisheries Rosenstiel School of Marine and Atmospheric Science University of Miami Florida, USA

...

xlll

xiv

List of' Contributors

L.H. Evans Aquatic Science Research Unit Muresk Institute of Agriculture Curtin University of Technology P.O. Box U1987 Perth Western Australia 6845 Australia A.A. Fonteles-Filho Instituto de Cigncias do Mar Universidade Federal do CearB Av. Da Aboliqdo 3207-Fortaleza CE 60165-081 Brazil

H. Fushimi Fukuyama University Sanzo Gakuen-cho Fukuyama Hiroshima 729-0292 Japan D.J. Gilbert National Institute of Water and Atmospheric Research P.O. Box 14-901, Kilbirnie Wellington 6003 New Zealand J.C. Groeneveld Marine and Coastal Management Department of Environmental Affairs and Tourism P. Bag X2 Rogge Bay 8012 South Africa

S. Guzman del Prbo Instituto Politecnico Nacional Escuela Nacional de Ciencias Biologicas Laboratorio de EcoligiB Marine Ap. Postal 26-375 02860 Mexico DF

List of Contributors

N.G. Hall Bernard Bowen Fisheries Research Institute Western Australian Marine Research Laboratories P.O. Box 20 North Beach Western Australia 6020 Australia

W.F. Herrnkind Department of Biological Science Florida State University Tallahassee, FL 32306 USA J.H. Hunt Florida Department of Environmental Protection Marine Research Institute South Florida Research Laboratory 2796 Overseas Highway Suite 119 Marathon, FL 33050-2227 USA M.A. Igarashi Department of Fisheries Engineering University of Ceara Fortaleza-CE Brazil

J.B. Jones Fish Health Section Fisheries Western Australia P.O. Box 20 North Beach Western Australia 6020 Australia A. Kanazawa Faculty of Fisheries University of Kagoshima 4-50-20 Shimoarata Kagoshima 890-0088 Japan

xv

J. Kittaka Research Institute for Marine Biological Science Research Institutes for Science and Technology The Science University of Tokyo Nemuro City, Fisheries Research Institute Hokkaido 087-0166 Japan

S. Konosu 1-26-6 Kugahara Ota-ku Tokyo 146-0085 Japan D. Latrouite Institut Franqais de Recherches pour 1'Exploitation de la Mer Direction Ressources Vivantes, Ressources Halieutiques BP 70 F-29280 Plouzank France

R.N. Lipcius Virginia Institute of Marine Science The College of William and Mary Gloucester Point, VA 23062 USA R. Litchfield SIR Pty Ltd Sydney Australia

E. Lozano-Alvarez Universidad Nacional Autonoma de Mkxico Instituto de Ciencias del Mar y Limnologia Unidad Academica Puerto Morelos Ap. Postal 1152 Cancun QR 77500 Mt5xico

List of Contributors

A.B. MacDiarmid National Institute of Water and Atmospheric Research P.O. Box 14-901, Kilbirnie Wellington 6003 New Zealand

R. Melville-Smith Bernard Bowen Fisheries Research Institute Western Australian Marine Research Laboratories P.O. Box 20 North Beach Western Australia 6020 Australia S. Mikami Australian Fresh Corporation c/o QDPI Bribie Island Aquaculture Research Centre P.O. Box 2066 Bribie Island Queensland 4507 Australia J.L. Munro International Centre for Living Aquatic Resources Management (ICLARM) Caribbean/Eastern Pacific Office Suite 158 Inland Messenger Service Road Town, Tortola British Virgin Islands K. Nakamura Faculty of Fisheries University of Kagoshima 4-50-20 Shimoarata Kagoshima-shi 890-0056 Japan

M. Nonaka Tokyo University of Fisheries 4-5-7 Kounan Minato-Ku Tokyo 108-8477 Japan

xvii

x vi ii List

of' Cont rihict ors

J.R. Ovenden Southern Fisheries Centre P.O. Box 76 Deception Bay Queensland 4508 Australia

A.F. Pearce CSIRO Division of Marine Research P.O. Box 20 North Beach Western Australia 6020 Australia J. Penn Bernard Bowen Fisheries Research Institute Western Australian Marine Research Laboratories P.O. Box 20 North Beach Western Australia 6020 Australia

B.F. Phillips Curtin University of Technology P.O. Box U1987 Perth Western Australia 6845 Australia

D.E. Pollock Marine and Coastal Management Department of Environmental Affairs and Tourism P. Bag X2 Rogge Bay 8012 South Africa J.J. Polovina Honolulu Laboratory Southwest Fisheries Science Center National Marine Fisheries Service, NOAA 2570 Dole Street Honolulu, Hawaii 96822-2396 USA

List of Contributors

G.K. Reck Institute of Applied Ecology University of San Francisco of Quito Quito Ecuador

B.I. Ruttenberg School of Forestry and Environmental Studies Yale University New Haven, CT USA D.S. Schoeman Marine and Coastal Management Department of Environmental Affairs and Tourism P. Bag X2 Rogge Bay 8012 South Africa R.N. Stevens Western Australian Fishing Industry Council P.O. Box 55 Mount Hawthorn Western Australia 691 5 Australia

H. Sugita Department of Marine Science and Resources Nihon University Fujisawa Kanagawa 252-8510 Japan D. Sykes New Zealand Rock Lobster Industry Council P.O. Box 24901 Wellington New Zealand

xix

xx

List of Contributors

F. Takashima Tokyo University of Fisheries 4-5-7 Konnan Minato-ku Tokyo 108-8477 Japan

M. Tsuruta Clean Bio Consulting Co. Ltd. Shirio-cho 438 Inba-gun Chiba-ken Japan K. Yamaguchi 1608, Hikawa Okutama Tokyo 198-0212 Japan T. Yamakawa Fisheries Research Institute of Mie Hamajima, Shima Mie 517-0404 Japan

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Introduction

Ecology and Fishery Biology of Spiny Lobsters R.N. LIPCIUS Virginia Institute of Marine Science, The College of William and Mary, Gloucester Point, VA 23062, USA

D.B. EGGLESTON Department of Marine, Earth and Atmospheric Sciences, North Carolina State University, Raleigh, NC 27695-8208, USA

Introduction Spiny (or rock) lobsters (Crustacea: Decapoda: Palinuridae) are ubiquitous in tropical and temperate seas (Fig. 1). Their value as a resource for food, for revenue, and for recreational and aesthetic value is undeniable. Spiny lobsters support some of the largest commercial fisheries in the world (Table 1), while also sustaining artisanal fisheries on remote islands or where they are in low abundance. Ecologically, palinurids are important links in marine food webs ranging from the deep ocean to shallow littoral habitats. In shallow coastal zones, palinurids are major predators of various benthic species (e.g. snails, clams and urchins) and important prey of larger predators (e.g. sharks and finfish). Their widespread occurrence and exploitation reflect the evolutionary and ecological success of the Palinuridae, and underscore the need for comprehensive ecological investigations and effective conservation strategies. In this chapter, an updated general overview is given of the biology, ecology and fisheries for palinurid lobsters, based on the earlier review (Lipcius & Cobb, 1994). Thus, the chapter serves as an introduction to the book, and as background information for subsequent chapters, which are up-to-date reviews of palinurid fisheries world-wide, and case studies dealing with key ecological and fisheries issues. This chapter is not exhaustive; rather, it gives the reader sufficient information to understand and appraise subsequent chapters. For additional information, the reader may consult the two-volume set on the biology and management of lobsters (Cobb & Phillips, 1980a, b), particularly those chapters dealing with palinurid fisheries and ecology (Bowen, 1980; Herrnkind, 1980; Kanciruk, 1980; Morgan, 1980; Phillips & Sastry, 1980; Phillips et al., 1980). Volume 43(11), 1986, of the Canadian Journal of Fisheries and Aquatic Sciences contains contributed papers from the 1985 International Workshop on Lobster Recruitment, and portrays advances in our understanding of lobster ecology and management, with emphasis on recruitment issues. Of the contributions in that volume, 12 are specifically devoted to palinurids. Distribution, identification and commercial trade of lobsters are detailed by Williams (1986, 1988) and Holthuis 1

2

Spiny Lobsters: Fisheries and Culture

Fig. 1 World-wide distribution of palinurid lobsters.

(1991). Cobb & Wang (1985) provide a comprehensive overview of the fisheries biology of clawed lobsters, spiny lobsters and freshwater crayfishes. More recent collections of spiny lobster biology and fisheries include the earlier edition of Spiny Lobster Management ( Ed. by B.F. Phillips, J.S. Cobb and J. Kittaka, 1994), as well as special issues of Crustaceana [Vol. 66(3), 1994] and Marine and Freshwater Research [Vol. 48(8), 1997].

Palinurid systematics, evolution and morphology Systematics and evolution The Palinuridae comprises over 47 species (Holthuis, 1991; George, 1997), of which about 33 species support commercial fisheries (Williams, 1988) (Tables 1 and 2). The family Palinuridae consists of decapod crustaceans in the superfamily Palinuroidea, which encompasses the Synaxidae (e.g. Palinurellus spp.) and the Scyllaridae (i.e. slipper lobsters), in addition to the palinurids (Williams, 1988; Holthuis, 1991; George, 1997). The Palinuroidea, along with the other lobster superfamilies (e.g. Nephropoidea, clawed lobsters), are contained within the suborder Macrura Reptantia, which consists of reptant (i.e. crawling) decapods, in contrast to the natant (i.e. swimming) decapods such as shrimp. Interestingly, Holthuis (1991) notes that the genera Panulirus and Linuparus are anagrams derived from Palinurus by White (1847) when he split the genus Palinurus into three genera. The palinurid

Hemisphere

N±S

Zone

Tropical

regius Panulirus spp.

East Africa, Indonesia New Guinea, East Africa Pacific Islands Thailand, India, Pakistan, SE Asia NW Africa Tropical

Geographical location

homarus ornatus penicillatus polyphagus

Jasus Caribbean, Florida, Brazil Ecuador, Panama Brazil

Palinurus

argus gracilis laevicauda

Panulirus

Table 1 Major fisheries for palinurid lobstersa

10 677

38 020

World catchb (mt)

14.3%

50.8%

Percentage of palinurid catch

Ecology and Fishery Biology of Spiny Lobsters 3

N

Subtropical

S

Hemisphere

continued.

Zone

Table 1

stimpsoni cygnus pascuensis

longipes marginatus

interruptus japonicus

inflatus

Panulirus

charlestoni delagoae

Palinurus

verreauxi

Jasus

East Australia, New Zealand

Hong Kong Western Australia Easter Islands Cape Verde Islands SE Africa, Mozambique

West Mexico, Guatemala, Honduras California Japan, South China Sea China, Japan Hawaii

Geographical location

3689

42 294c

11 450

1267

World catchb (mt)

4.9%

0.1% 0.4%

15.3%

1.7%

Percentage of palinurid catch

4 Spiny Lobsters: Fisheries and Culture

N±S

S

Temperate, subtropical

Temperate

Panulirus

b

Modified after Morgan (1980). Annual mean from 1991±1995 (FAO, 1997). c Mean from 1991±1993. c Mean from 1991±1993 and 1995.

a

Total palinurid catch

Hemisphere

continued.

Zone

Table 1

gilchristi

mauritanicus and elephas

Palinurus

St. Paul and New Amsterdam Islands Tristan de Cunha, St Helena

paulensis tristani

New Zealand Juan Fernandez, Chile SW Africa, Spain South Australia

West Africa, Mauritania, Mediterranean Basin, Western Europe South Africa

Geographical location

edwardsii frontalis lalandii edwardsii

Jasus

0.5% 100.1%

363 74 817

4.0% 0.1% 2.8%

1.3%

962d 3014 24 2129

3.9%

Percentage of palinurid catch

2886

World catchb (mt)

Ecology and Fishery Biology of Spiny Lobsters 5

6

Spiny Lobsters: Fisheries and Culture

Table 2 Palinurid species Genus Palinurus

Species

Other names

Location

Langouste

Cape Verde Island SW Indian Ocean NE Atlantic S South Africa

mauritanicus

Crayfish, spiny lobster Crawfish Gilchrist's crayfish, spiny lobster Langouste

argus cygnus

Florida spiny lobster, bug W Atlantic Western rock lobster W Australia

echinatus gracilis guttatus homarus homarus

Spiny lobster Blue lobster, langosta azul Spotted spiny lobster Green-scalloped rock lobster Deep-scalloped rock lobster Red-scalloped rock lobster

Central Atlantic Central E Pacific Caribbean Indian Ocean

inflatus interruptus japonicus laevicauda

Langosta Californian spiny lobster Ise-ebi Longosta

Mexico California Japan NE South America

longipes femoristriga

White-whiskered rock lobster Spotted-legged rock lobster Hawaiian lobster Ornate rock lobster

W Pacific

charlestoni delagoae elephas gilchristi

Panulirus

homarus megasculpta homarus rubellus

longipes longipes marginatus ornatus

W Arabian Sea SW Indian Ocean

Indian Ocean Hawaii Indo-West Pacific

pascuensis penicillatus

Longosta, crayfish Double-spined rock lobster

Easter Island Indo-West Pacific

polyphagus

Long-whiskered rock lobster Langouste royale

Indo-West Pacific

Hong Kong rock lobster Painted rock lobster Ryoma-ebi

South China Sea Indo-West Pacific Japan, Mauritius West Indies W Indian Ocean

regius

Justitia

E Atlantic

stimpsoni versicolor japonica longimanus mauritiana

E Atlantic

Ecology and Fishery Biology of Spiny Lobsters

7

Table 2 continued Genus

Species

Other names

Location

Jasus

caveorum edwardsii

Crayfish, rock lobster

Eastern South Pacific New Zealand

edwardsii frontalis lalandii paulensis tristani verreauxi

Linuparus

Palinustrus

Projasus

Cape crayfish, rock lobster Longouste Crayfish, rock lobster

S coast Australia Juan Fernandez W South Africa St Paul's Island Tristan da Cunha Tasman Sea, New Zealand

somniosus sordidus

E South Africa Australia, S China Sea

trigonus

Australia, Japan

mossambicus truncatus

E Africa Caribbean

waguensis Puerulus

Southern rock lobster

Wagu-ebi

Japan

angulatus carinatus

E Africa, New Guinea E Indian Ocean

sewelli velutinus

Arabian Sea Indonesia

bahamondei parkeri

SE Pacific Parker's crayfish

E South Africa

Adapted from Phillips et al. (1980).

lobsters are referred to by various common names. `Spiny' and `rock' lobsters belong to the same group of genera (i.e. the Palinuridae), but reflect different local traditions in naming. For consistency, we use `spiny lobster(s)' when referring to any of the palinurids. The classic studies by George & Main (1967) and George (1969) on evolutionary relationships in the Palinuridae were based on morphological characters; they divided palinurid lobsters into the Stridentes and Silentes. The four major morphological features included the relative size and disposition of the supraorbital processes, the elevation of the eyestalks, the structure of the pleopod on the second abdominal segment of the female and the general shape of the carapace. Coincident

8

Spiny Lobsters: Fisheries and Culture

with an evolutionary habitat trend from deeper to shallow waters, there was a morphological trend towards lateral separation and elevation of supraorbital processes, elongation and elevation of eyestalks, enlargement of the specified pleopod and rounding of the carapace, as exemplified in Panulirus. Presumably these features were adaptive in avoidance of predation in shallow, well-lit habitats, and to increase the effective area for aeration of the egg mass (George & Main, 1967). Within the palinurids, there appear to be two basic distribution patterns, one a circumpolar high-latitude pattern (e.g. Jasus), and the other a circumequatorial lowlatitude pattern (e.g. Panulirus). The highest diversity of palinurids occurs in the warm, shallow-water regions, probably as a result of the greater variety of habitats. Pollock (1990, 1992, 1993) examined the mechanisms producing speciation and a broad distribution in Jasus and Panulirus. The wide distribution of both genera was presumed to result from the long-distance dispersal capabilities of the teleplanic phyllosome larvae combined with circumoceanic gyral circulation routes. Speciation probably resulted from alterations in ocean current systems, particularly those associated with changes in sea level, and the emergence and subsidence of seabed ridges, rises and seamounts, such as those which occurred during the Pleistocene. In particular, the intensity and location of gyral flow, which tends to limit larval dispersal and thereby facilitates allopatric speciation, varied between glacial and interglacial periods and probably determined rates of speciation in palinurids (Pollock, 1993). Species integrity has probably been maintained by behavioural barriers to larval or post-larval recruitment, such that larvae and post-larvae are attracted to physical and chemical cues associated with the natal environment (Pollock, 1990, 1992). More recently, George (1997) has provided a thorough review of the evolution of Jasus and Panulirus (Fig. 2, Table 3). George postulates that the collective effects of tectonic plate movements, global changes in climate and oceanic currents, which influence larval transport, and alterations in habitat characteristics have promoted genetic differentiation and speciation in palinurids. `Some species responded to shifts in currents, some drifted apart with the continents, some adapted to remote islands and seamounts, some moved polewards as the climate cooled, some adapted to newly cretaed habitats and others became partially isolated by geographic barriers' (Fig. 2) (George, 1997). These conclusions regarding the evolution of palinurids are in keeping with our recent understanding of ecologically important forces, specifically the influential roles of recruitment processes (Phillips et al., 1994a, b; Lipcius et al., 1997; McWilliam & Phillips, 1997), habitat relationships (Herrnkind et al., 1994, 1997; Acosta & Butler, 1997) and spatial dynamics (Punt & Kennedy, 1997), as well as genetic relationships (Brasher et al., 1992; Ovenden et al., 1992, 1997; Ovenden & Brasher, 1994; Silberman et al., 1994).

Ecology and Fishery Biology of Spiny Lobsters

9

Continental shelf fronting open ocean

Widespread equatorial

0

0

Isolated island and seamount

Restricted Sea

Riverinfluenced shelf

Fig. 2 Linkages between geographical location, shelf and oceanic circulation, and postulated larval transport in palinurids. Adapted from George (1997).

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Spiny Lobsters: Fisheries and Culture

Table 3 Ecological groupings for Jasus and Panulirus Group

Ecological type

Description

Species

A

Widespread equatorial

Panulirus: P. penicillatus, P. longipes subspecies, P. versicolor, P. homarus homarus, P. echinatus

B

Continental shelf fronting open ocean

Shallow, mostly clear water and low runoff on islands or continents. Large-scale oceanic dispersal of larvae. Deep (0±100 m), clear water and low runoff from land. Adjacent oceanic waters well defined by gyral, eddy or upwelling systems. Larvae retained within 1000±1500 km of coast.

C

Isolated island and seamount

D

Restricted sea

E

River influenced shelf

Deep (0±200 m) clear water and low runoff. Geographically positioned in a path of strong unidirectional currents. Larvae probably retained in back eddies and Taylor columns. Shallow, clear waters and low runoff. Enclosed by geographic boundaries. Larvae mostly retained within boundaries. Shallow, turbid water and heavy to moderate runoff. Larvae probably retained in local `estuarine' waters.

Panulirus: P. cygnus, P. japonicus, P. marginatus, P. interruptus, P. gracilis, P. h. rubellus, P. h. megasculpta, P. argus (Brazil) Jasus: J. verreauxi, J. verreauxi-NZ, J. edwardsii, J. e. novaehollandiae, J. lalandii Panulirus: P. pascuensis Jasus: J. tristani, J. paulensis, J. caveorum, J. frontalis

Panulirus: P. guttatus, P. argus (Caribbean), P. inflatus

Panulirus: P. polyphagus, P. laevicauda, P. regius, P. stimpsoni, P. ornatus

Adapted from George (1997).

Morphology Spiny lobsters are among the largest of crustaceans; the total body length sometimes attains 60 cm, as in the green rock lobster, Jasus verreauxi (Kensler, 1967; Holthuis, 1991). This body length is approximately equivalent to a carapace length of 24 cm; carapace length (i.e. the distance from the base of the supraorbital horns to the posterior edge of the carapace) is the usual quantitative measure of body length in spiny lobsters (Cobb & Wang, 1985). The body parts of a representative lobster are compartmentalized into a cephalothorax, which consists of the fused head and thorax, and an abdomen,

Ecology and Fishery Biology of Spiny Lobsters

11

with their respective appendages (Fig. 3; Holthuis, 1991). The cephalothorax comprises 14 fused somites, each with a pair of appendages; the first six somites constitute the cephalon and the last eight the thorax (Fig. 3). Appendages on the cephalothorax include the eyes, which may be movable, reduced and immovable, or altogether absent (Holthuis, 1991); the antennae and antennules, which provide protection, mechanoreception and chemoreception (Ache & Macmillan, 1980; Zimmer-Faust & Case, 1982, 1983; Zimmer-Faust, 1991); the mouth parts, which include the mandibles, maxillae and maxillipeds; and five pairs of walking legs. The cephalothorax is encased dorsally by a carapace extending from the last thoracic somite to the eyes, sometimes forming a projecting rostrum beyond the eyes. Laterally, the carapace encloses the branchial chamber, which protects the gills. In some palinurids, an antennular plate carries spines and is formed into a soundemitting stridulatory apparatus in the Stridentes group of palinurids (e.g. Panulirus); both structures are useful taxonomically (George & Main, 1967; Holthuis, 1991).

Fig. 3

Morphology of a palinurid lobster. Adapted from Holthuis (1991).

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Spiny Lobsters: Fisheries and Culture

Those palinurids without a stridulatory apparatus are distinguished as the Silentes group. The ventral portion of the cephalothorax forms a sternum, which bears the gonopores at the bases of the third pair of pereiopods in females and the fifth pair in males (Fig. 3). Six separate somites comprise the abdomen, each protected by chitinous coverings on the dorsal, ventral and lateral (pleura) portions. The pleura are characteristically shaped or ornamented, and enclose the pleopods, which are used as swimmerets and form appendages on the first five abdominal somites (Fig. 3). The first two pairs of pleopods are often formed into copulatory organs in males, having a stiff style-like appearance, whereas in mature females the pleopods become setose to enclose the external egg mass (Lipcius & Herrnkind, 1987). Posteriorly, the sixth abdominal somite forms the tail fan, consisting of the heavily calcified uropods and the telson, which represents either a plate-like median appendage of the sixth somite or a seventh abdominal somite (Holthuis, 1991). The powerful abdominal musculature and blade-like structure of the tail fan effect the swift, backward escape response characteristic of many decapods (Cobb & Wang, 1985).

Life history and ecology General ecology Spiny lobsters inhabit temperate and tropical seas (Fig. 1), but most species and the highest abundances are found in the tropics (Holthuis, 1991). Habitats include the intertidal through the deep sea down to almost 3000 m depth (Fig. 4, Table 3), with shelter provided within substrates encompassing rocky crevices, mud and sand bottoms, and vegetated beds. Individuals usually seek shelter during daytime (Herrnkind, 1980; Cobb, 1981; Lipcius & Herrnkind, 1982; Cobb & Wang, 1985), although mating behaviour and mass migrations sometimes disrupt the normal diel rhythms in activity (Herrnkind, 1980; Lipcius et al., 1983; Lipcius & Herrnkind, 1985; MacDiarmid et al., 1991), which may be endogenously driven (Williams & Dean, 1989). Habitation of shelters is often communal, probably dictated by gregarious behaviour adapted for protection from diurnally active predators (Berrill, 1975; Cobb, 1981; Zimmer-Faust & Spanier, 1987; Eggleston & Lipcius, 1992). The aggregative behaviour may be driven by chemical (Zimmer-Faust et al., 1985) or visual stimuli, and may differ depending on the quality of available habitats (Trendall & Bell, 1989; Eggleston & Lipcius, 1992). Spiny lobsters are ecologically dominant because of the same characteristics which make them commercially valuable, i.e. their large size and abundance. Spiny lobsters prey nocturnally upon a diverse assemblage of benthic and infaunal species, including molluscs (e.g. snails and clams), smaller crustaceans, echinoderms, polychaetes (Fielder, 1965; Heydorn, 1969; Berry, 1971b; Herrnkind et al., 1975;

Ecology and Fishery Biology of Spiny Lobsters

13

Fig. 4 Spatial distribution of palinurid lobsters by water depth, temperature and latitude. Adapted from George & Main (1967).

Pollock, 1978; Engle, 1979; Berry & Smale, 1980; Andree, 1981; Joll & Phillips, 1984; Edgar, 1990) and algae (Joll & Crossland, 1983), while concurrently serving as prey for larger predators including various species of finfish, sharks and octopus (Cobb & Wang, 1985; Herrnkind & Butler, 1986; Howard, 1988; Eggleston et al., 1990, 1992, 1997; Smith & Herrnkind, 1992). Commercially important palinurids do not overlap significantly in spatial distribution when examined as a function of depth and latitude (Fig. 4) (George & Main, 1967; Cobb & Wang, 1985), although congeners can coexist in the same habitats (e.g. Panulirus argus and P. guttatus in Caribbean reefs; Herrnkind & Lipcius, 1989). Jasus and Panulirus, the two shallow-dwelling genera, typically inhabit temperate and tropical habitats, respectively (Fig. 4, Table 3). The remaining genera in the Palinuridae inhabit deep-water habitats (Cobb & Wang, 1985). Berry (1971a) examined habitat use in palinurid lobsters off the east coast of southern Africa, where seven of the eight extant genera have been recorded (i.e. Panulirus, Palinurus, Jasus, Projasus, Palinustus, Puerulus and Linuparus). The five

14

Spiny Lobsters: Fisheries and Culture

species of Panulirus, which inhabit shallow areas down to 18 m depths, appear to be separable ecologically on the basis of water turbidity, temperature, depth and tidal range. The remaining genera are deep-water inhabitants and evidently separable on the basis of substratum type. For instance, Palinurus gilchristi occupies rocky habitats, whereas Palinurus delagoae occurs outside rocky areas. Similarly, Puerulus is captured on muddy bottoms, whereas Linuparus inhabits rocky areas. George (1974) also reviewed habitat utilization of Panulirus in the Indo-West Pacific, showing the characteristic separation of species on the basis of habitat features (Fig. 5). One of the most impressive and characteristic features of the palinurid life history involves long-distance migrations, sometimes conducted in dramatic en masse fashion (Herrnkind, 1980). Migrations are often seasonal and can occur inshore± offshore or alongshore, as in the mass migrations. For instance, Panulirus argus migrates en masse in various locations throughout the Caribbean region after the first cold front in autumn (Herrnkind & Cummings, 1964; Herrnkind, 1969, 1980). During the movement, lobsters migrate in queues (i.e. single-file lines) both day and night for 2±3 days, with up to 64 individuals in a single queue. Other species performing long-distance migrations include J. edwardsii along the south-eastern New Zealand coast (Street, 1971), J. verreauxi in the North Cape region of New Zealand, Panulirus ornatus in the Gulf of Papua and Torres Strait (Moore & MacFarlane, 1977) and Panulirus cygnus during the exodus of `white' juveniles to deeper waters (George, 1958; Chittleborough, 1970; Phillips, 1983). These migrations

Fig. 5 Habitat specialization in palinurid lobsters. Adapted from George (1974).

Ecology and Fishery Biology of Spiny Lobsters

15

are variously associated with reproduction (P. ornatus and Jasus), redistribution of juveniles to adult habitats (P. cygnus and, possibly, P. argus), or avoidance of physically stressful environmental conditions (P. argus). Spiny lobsters have been implicated as key predators in a variety of benthic habitats (Tegner & Levin 1983; Edgar, 1990), and their selective predation is apparently responsible for profound effects on species composition and sizefrequency distributions of invertebrates such as sea urchins, mussels and gastropods (Griffiths & Seiderer, 1980; Tegner & Levin, 1983; Joll & Phillips, 1984; Barkai & McQuaid, 1989; Edgar, 1990). Given the extended, nocturnal activity patterns of lobsters on the foraging grounds, it is likely that lobsters and other reef associates have a significant effect on benthic community structure and a negative effect on secondary production of certain benthic species. Predator impacts on benthic macrofauna may also vary seasonally with lobster abundance, and probably diminish with distance from shelter sites (Joll & Phillips, 1984; Jernakoff, 1987; Jernakoff et al., 1987). In addition, the effects of predator removal (i.e. spiny lobsters) through exploitation may impact the commmunity structure of ecosystems directly or in a cascading fashion (e.g. by removal of a dominant competitor), particularly if the spiny lobster is a keystone predator (sensu Paine, 1966). In contrast, role reversals can occur wherein prey of spiny lobsters inhibit the persistence or establishment of populations of spiny lobster. For instance, where rock lobsters (Jasus lalandii) are abundant in South African waters they control the abundance and species composition of mussels and whelks; in other habitats whelks are able to kill and consume immigrant rock lobsters, effectively preventing the establishment of a local population (Barkai & McQuaid, 1988). Large, transient environmental impacts to ecosystems that support spiny lobsters can also result in mass mortality. For example, periodic coastal upwelling and anoxia along the Namibian and South African coast result in mass mortality of Jasus lalandii (Grobler & Noli-Peard, 1997). Hypoxia in this same region appears to limit movement and growth rates of J. lalandii (Grobler & Noli-Peard, 1997).

Life history The palinurid life history reflects the predominant developmental pattern in marine crustaceans, i.e. release of a pelagic larva after embryonic development (Sastry, 1983a). Whereas most crustaceans with a pelagic larval stage release a nauplius larva (Sastry, 1983a), the palinurids pass the naupliar phase within the egg before hatching the distinctive phyllosome larvae. The pelagic larval phase is one component of a life history which, similarly to most crustaceans, does not easily conform to evolutionary theory incorporating r- and K-selection (Sastry, 1983b). Rather, the palinurid life history incorporates aspects of both r- and K-selection, including r-selected characters such as a large number of offspring and absence of parental care, and K-selected features such as delayed maturity and iteroparity (Sastry, 1983b). These

16

Spiny Lobsters: Fisheries and Culture

compromises are apparently in response to the differing pressures exerted on various phases of the life history, such as food or shelter limitation, predation pressure and physical transport processes. Spiny lobsters exhibit five major phases within the life cycle: adult, egg, phyllosoma (larval stages), puerulus (post-larval stage) and juvenile (Phillips et al., 1980), although the juvenile phase has recently been separated into an algal or early benthic phase (Marx & Herrnkind,1985a; Herrnkind & Butler, 1986) followed by the characteristic older juvenile phase, similar in habits to adults (Fig. 6). Adults frequently aggregate during the day in crevices of coral and rocky reefs (Berrill, 1975; Cobb, 1981; Zimmer-Faust & Spanier, 1987). At sunset spiny lobsters emerge from their dens to forage nocturnally in nearby habitats such as reef flats and seagrass beds (Herrnkind et al., 1975; MacDonald et al., 1984). Shortly before reaching adulthood many spiny lobsters undergo movements from the nursery habitat to the characteristic deeper reef habitats (Herrnkind, 1980), where reproduction occurs (Lipcius, 1985). Fertilization is external (Cobb & Wang, 1985), even in Jasus (MacDiarmid, 1988); the male deposits a spermatophoric mass on the female's sternum. The spermatophore is subsequently rasped several hours prior to spawning, thereby releasing sperm for fertilization of the eggs as they are extruded on to the abdomen and pleopods (Lipcius & Herrnkind, 1987). Egg masses are generally spawned and hatched in the spring and summer by females located in offshore reef areas. Subsequently, the early phyllosoma (larval) stages are transported offshore by wind-driven surface currents into oceanic habitats (Phillips & McWilliam, 1986).

Larval ecology Recent studies in marine systems have stressed the importance of recruitment processes in the population dynamics of marine species (Gaines & Roughgarden, 1987; Doherty & Fowler, 1994; Lipcius et al., 1997; Dixon et al., 1999). Interannual fluctuations in populations of benthic invertebrates and demersal fishes depend on recruitment and post-settlement dynamics, and are regulated by planktonic larval and post-larval availability, settlement rates in suitable habitats, and post-settlement movements and mortality rates (Connell, 1985). Settlement rates further vary as a function of hydrodynamics, larval density, delivery and mortality rates, likelihood of settlement due to habitat quality, and settlement behavior (Lipcius et al., 1990; Herrnkind et al., 1994). Because oceanographic processes influence the larval and post-larval phases in different ways, and because most commercially important species have open populations, such a synthesis for palinurids and other marine species requires an approach that integrates the fields of meteorology, oceanography (physical, chemical and biological), marine ecology and fisheries biology. Along with coral and slipper lobsters, palinurids are the only decapod crustaceans possessing phyllosoma larvae in the life history (Phillips & Sastry, 1980). Phyllosomes (derived from the Greek phyllos, a leaf, and soma, a body) are

Ecology and Fishery Biology of Spiny Lobsters

Fig. 6

17

Schematized life cycle of palinurid lobsters.

dorsoventrally flattened, transparent and leaf-like larvae adapted for passive horizontal transport assisted by vertical migration. There are usually seven to 13 phyllosoma stages, with each representing one or more instars (Phillips & Sastry, 1980); sometimes a pre-phyllosome stage has been described, and is variously termed the `naupliosoma', `prenaupliosoma' and `prephyllosoma'. The pre-phyllosome stage lasts for no more than a few hours before ecdysis to the first phyllosoma stage; thereafter, larval durations differ greatly among palinurids, ranging from a few

18

Spiny Lobsters: Fisheries and Culture

months to almost 2 years before the last phyllosoma stage, approximately 35 mm in length, metamorphoses to the puerulus stage (Phillips & Sastry, 1980). Such variation is particularly evident in the cultured larvae of palinurids (Kittaka, 1994), such that the larval phase (i.e. the time from hatching until metamorphosis to the puerulus) encompassed 132 days in Palinurus elephas (Kittaka & Ikegami, 1988), 306 days in Jasus lalandii (Kittaka, 1988) and 340±91 days in Panulirus japonicus (Kittaka & Kimura, 1989). Studies of larval transport of palinurids have recently begun integrating oceanic or coastal circulation patterns with larval distribution (Fig. 2, Table 3) (George, 1997) and post-larval settlement patterns (Johnson, 1971; Phillips & McWilliam, 1986; Pearce & Phillips, 1988; Herrnkind et al., 1994; Lipcius et al., 1997; Eggleston et al., 1998). Quantitative information on the vertical migrations of larvae is essential to an understanding of transport mechanisms, larval sources, and recruitment processes in palinurids (Phillips & McWilliam, 1986; Yeung & McGowan, 1991). The importance of vertical migration in phyllosome transport is apparent in the larval behaviour of Panulirus cygnus (Rimmer & Phillips, 1979). The vertical migration behaviour of early phyllosomes (stages I±III) of P. cygnus places them near the surface. There they are transported offshore into the south-eastern Indian Ocean via surface wind drift at a speed of about 5.25 km/day (Phillips et al., 1979). This direction opposes the general circulation of the upper 300 m layer, which flows towards the coast of Western Australia at about 3.3 km/day. Mid- and late-stage P. cygnus phyllosomes (stages IV-IX) avoid the surface layer through an increased sensitivity to light (Rimmer & Phillips, 1979); thus, they become more subject to subsurface circulation, which returns them to the coast of Western Australia (Phillips, 1981). A different pattern exists for larvae of the Caribbean spiny lobster, P. argus, in south-eastern Florida, although the data are not extensive. In general, phyllosomes were distributed in the surface layer irrespective of larval developmental stage (Yeung & McGowan, 1991). However, there appear to be regional differences in ontogenetic vertical distribution patterns of phyllosomes, as well as the extent of local retention of spiny lobster larvae. Recently, P. argus phyllosomes, including late stages, were found in the coastal waters of south-west Cuba, where a gyre circulation persists (Yeung & McGowan, 1991). This gyre may retain phyllosome larvae locally, and thereby enhance the return of pueruli to south-western Cuba, probably resulting in the densest population of P. argus in the Caribbean. In contrast, on the northwestern coast of Cuba there is no gyre, but rather a rapid north-flowing current with low larval abundances. Off the Florida Keys, the Pourtales Gyre does not persist long enough (i.e. approximately 1±2 months) to retain phyllosomes during the entire larval development. In Exuma Sound, Bahamas, gyral flow apparently drives the spatial distribution of larvae and settlement patterns of post-larvae of the Caribbean spiny lobster (Lipcius et al., 1997). Thus, patterns of larval retention in palinurids apparently vary both within and between species, and require extensive ecological information (e.g. physical transport processes in oceanic habitats) to determine the key sources of variation in the larval phase.

Ecology and Fishery Biology of Spiny Lobsters

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Post-larval ecology After 6±24 months in the plankton, the last planktonic larval stage metamorphoses into the puerulus, a transparent, free-swimming, non-feeding post-larval stage that moves inshore where it settles to the benthos (Phillips & Olsen, 1975; Phillips, 1981; Calinski & Lyons, 1983; Nishida et al., 1990). Metamorphosis is probably dictated by the nutritional state of the phyllosoma, rather than by environmental cues (McWilliam & Phillips, 1997). Pueruli apparently navigate to the shallow-water juvenile nurseries by means of a complex receptor system formed by the antennae and a pinnate setal system, which enables orientation to cues associated with coastlines (Phillips & Macmillan, 1987). Once in the nursery grounds, pueruli prefer to settle in architecturally complex habitats, such as in the red alga Laurencia by post-larval P. argus (Marx & Herrnkind, 1985a; Herrnkind & Butler, 1986; Herrnkind et al., 1994), rocky crevices by J. edwardsii (Booth, 1979), and small holes near algae by P. japonicus (Yoshimura & Yamakawa, 1988) and P. interruptus (Serfling & Ford, 1975). The preference for these habitats is mediated by their structural complexity and not by food availability, which becomes influential for the post-puerulus juveniles (Herrnkind et al., 1988, 1994). Floating, artificial settlement substrates have proven useful in quantifying postlarval settlement patterns in several species, including Panulirus argus (Witham et al., 1968; Little, 1977; Little & Milano, 1980; Marx, 1986; Bannerot et al., 1991; Forcucci et al., 1994; Acosta et al., 1997; Eggleston et al., 1998), P. cygnus (Phillips, 1972, 1986), P. japonicus (Nonaka et al., 1980), P. marginatus (MacDonald, 1986) and J. edwardsii (Booth, 1979, 1989; Booth & Tarring, 1986; Booth & Bowring, 1988; Breen & Booth, 1989; Hayakawa et al., 1990; Booth et al., 1991). In the central Bahamas, post-larval settlement on `Witham-type' artificial settlement substrates was strongly correlated with the concentration of pueruli in the water column, and flux past a given point (Eggleston et al., 1998). In Florida Bay, post-larval settlement on modified `Witham-type' artificial settlement substrates correlated with planktonic abundance and settlement of postlarvae at regional scales of tens of kilometres, but not at local scales of tens of metres (Butler & Herrnkind, 1992). Abundance of P. argus juveniles in Florida Bay also correlated with post-larval supply, as measured with artificial settlement substrates, to the region 8 months earlier (Forcucci et al., 1994). Quantitative data from settlement on artificial settlement substrates have proven useful in successfully predicting future population size and fishery exploitation (Morgan et al., 1982; Phillips, 1986; Breen & Booth, 1989). Although shelter is generally thought to limit the abundance of early benthic phase lobsters in some areas (Ford et al., 1988; Butler et al., 1995), post-larval settlement may affect local abundance of juvenile lobsters. For example, a high post-larval supply of P. argus to the Middle Florida Keys, USA, fortuitously coincided with a massive dieoff of sponge refugia which, when combined with the availability of alternative, previously underused shelter (solution holes, coral heads, etc.), offset any major negative effects of sponge loss on juvenile population size (Butler et al., 1995;

20

Spiny Lobsters: Fisheries and Culture

Herrnkind et al., 1997). Further investigations are necessary to delineate the respective roles of pre- versus post-settlement processes on population abundance and structure. Studies that have used artificial settlement substrates to measure relative rates of settlement generally show that spatiotemporal variation in settlement patterns are often driven by distinct periodic (e.g. lunar phase, seasonality) and stochastic (wind speed and direction, coastal sea-level, etc.) factors. For example, post-larval influx of P. argus typically occurs during nocturnal flood tides during the first quarter of the lunar phase, with consistently highest settlement observed during the autumn (September±November) (Acosta et al., 1997; Eggleston et al., 1998). New-moon spring tides provide the potential for relatively strong tidal transport owing to increased tidal ranges and because recruitment during the darkest phase of the lunar cycle could reduce susceptibility to visual predators (Acosta, 1997). Seasonal differences in post-larval influx may reflect seasonal variation in current patterns that could influence larval and post-larval retention and advection, as well as seasonal spawning (Eggleston et al., 1998). In terms of stochastic factors influencing post-larval supply, wind-induced along-shore transport explained approximately 30% and 50% of the variation in settlement anomalies of P. argus in the Florida Keys and central Bahamas, respectively (Acosta et al., 1997; Eggleston et al., 1998). The unexplained variation (50±70%) in post-larval influx of P. argus to the Florida Keys and central Bahamas could be due to a variety of biological and physical factors, including local and regional patchiness of pueruli, variable larval developmental rates and vertical migration behaviour of larvae, regional scale meteorological influences on water levels, and the strength of coastal upwelling and down-welling. Post-larval influx in the western Australian rock lobster (P. cygnus) appears to be driven primarily by stochastic factors that may vary periodically over decadal or longer time scales. For example, post-larval influx of P. cygnus is correlated with the Southern Oscillation Index, coastal sea level, sea surface temperature, salinity and rainfall, as an index of storms (Phillips et al., 1991). In P. cygnus, post-larval settlement is high in years when El NinÄo Southern Oscillation (ENSO) events are minimal, resulting in a strong Leeuwin current which transports pueruli towards coastal nursery habitats (Pearce & Phillips, 1988). Depth of settlement is generally in the shallows, although pueruli can settle in deep habitats, potentially enhancing encounter rates with suitable habitats (Booth et al., 1991; Heatwole et al., 1991).

Juvenile ecology Once settled, the puerulus metamorphoses into the first benthic instar approximately 6±7 mm in carapace length (CL). Juvenile spiny lobsters can exhibit up to three ecologically distinct phases following settlement: algal phase, post-algal phase, and subadult. For instance, algal phase (i.e. early benthic phase, sensu Wahle & Steneck,

Ecology and Fishery Biology of Spiny Lobsters

21

1991; 5±15 mm CL) P. argus typically reside solitarily in or under large clumps of intricately branched red algae (Marx & Herrnkind, 1985a), which provide food and refuge (Marx & Herrnkind, 1985b; Herrnkind & Butler, 1986; Herrnkind et al., 1988). Similarly, early benthic phase P. cygnus occupy small holes on the face, in ledges and in caves on coastal limestone reefs, particularly holes with associated seagrass or algae (Jernakoff, 1990). Young juvenile P. interruptus shelter in Phyllospadix seagrass beds with dense cover over rocky bottom (Parker, 1972; Serfling, 1972; Engle, 1979) and early benthic phase P. japonicus reside in small crevices in rocks or algal clumps (Yoshimura & Yamakawa, 1988). As juvenile lobsters reach a size of 20±45 mm CL, they begin to move out of algal clumps to small crevices in algal-covered rock rubble (Andree, 1981), before becoming gregarious with larger juvenile lobsters during the day under crevices provided by rocks, sponges, octocoral or other structures (Herrnkind et al., 1975; Andree, 1981; Marx & Herrnkind, 1985a; Herrnkind & Lipcius, 1989; Forcucci et al., 1994; Butler & Herrnkind, 1997). For P. argus, this type of habitat may be rare in many areas of the Caribbean, where fringing mangroves (Acosta & Butler, 1997) with associated margins of seagrass, macroalgae and crevice shelters (Lipcius et al., 1998) function as nursery habitat for juvenile lobsters. At night, lobsters forage on small molluscs and crustaceans in the surrounding habitat (Andree, 1981; Herrnkind et al., 1994; Cox et al., 1997). Small, post-algal lobsters roam only metres from their daytime shelter (Herrnkind & Butler, 1986; Yoshimura & Yamakawa, 1988), but become nomadic and forage widely at about 45 mm CL (approximately 1 year post-settlement) (Herrnkind, 1980, 1983). As maturity approaches, approximately 2 years postsettlement (75 mm CL), spiny lobsters migrate to the reef tract. Size-dependent shifts in sociality have been identified for P. argus (Marx & Herrnkind, 1985), P. cygnus (Phillips et al., 1977), P. interruptus (Zimmer-Faust & Spanier, 1987), J. edwardsii (Macdiarmid, 1994) and P. ornatus (Dennis et al., 1997), but the mechanisms for such shifts are relatively poorly studied. Variation in the behaviour of post-algal lobsters may reflect the niche shift from full-time algal dwelling to diurnal crevice sheltering. For post-algal P. argus, however, there is no difference in predation risk between algal and crevice habitats, which may have explained the size at which this shift in habitat and sociality should occur (Childress & Herrnkind, 1994, 1997). The ontogenetic shift from solitary to gregarious shelter use by post-algal P. argus appears to be mediated by a size-dependent shift in receptivity to chemical attractants released by conspecifics, as well as by a massdependent release of the attractant leading to scale-dependent attraction (Ratchford & Eggleston, 1998). For example, algal-phase P. argus (<15 mm CL) are unresponsive to conspecific odours, whereas lobsters greater than 15 mm CL are attracted by conspecific odours (Ratchford & Eggleston, 1998). Small lobsters do not produce sufficient attractant to stimulate other lobsters at any but the shortest of distances (1±2 m); however, the attractant is additive, leading to increased quantities of scent emanating from shelters occupied by multiple lobsters (Ratchford & Eggleston, 1998). The additive nature of the conspecific attractant may explain

22

Spiny Lobsters: Fisheries and Culture

density-dependent gregariousness in P. argus (Eggleston & Lipcius, 1992). Odours from conspecifics positively influence shelter selection among several species of spiny lobster, including P. interruptus (Zimmer-Faust et al., 1985), P. argus (Ratchford & Eggleston, 1998) and J. edwardsii (M. Butler, unpubl. data). Chemotaxis may be one means of forming aggregations of lobsters, but is not a likely means of homing directly back from the long distances (hundreds of metres) that lobsters move from their dens during nightly foraging excursions (Herrnkind et al., 1975). At best, chemotaxis may explain short-distance navigation to a shelter. Shelter sharing among small, juvenile spiny lobsters has been proposed to be the result of a `guide-post effect', whereby lobsters can use cues from other lobsters to find shelter more quickly (Childress & Herrnkind, 1997) and locate shelter of high quality (Ratchford, 1999). Homing is common among the palinurids (Herrnkind, 1980), which return to their diurnal shelters before dawn after feeding at night. Adult lobsters often return to the den that they left the previous evening (Herrnkind et al., 1975) and strong den fidelity also appears to be characteristic of juveniles (Childress & Herrnkind, 1997). The mechanisms for homing have received some attention, but are poorly understood because investigations have been hampered by behavioural artefacts associated with handling lobsters. For example, Herrnkind et al. (1975) noted that 84% of newly tagged lobsters left their dens as opposed to the usual emigration rate of 58%; Davis (1977) similarly reported diver-induced lobster dispersal. The process of shelter selection and aggregation are highly intertwined. Small spiny lobsters may benefit from locating shelters containing larger lobsters that are better able to defend a shelter from predators (Berrill, 1975; Cobb, 1981; ZimmerFaust & Spanier, 1987; Mintz et al., 1994). Lobsters prefer shelters of a size that allows cohabitation (Spanier & Zimmer-Faust, 1988), as well as shelters scaled to their body size (Zimmer-Faust & Spanier, 1987; Eggleston et al., 1990; Eggleston & Lipcius, 1992), although selection of shelters scaled to body size varies with the presence or absence of conspecifics (Eggleston & Lipcius, 1992; Briones et al., 1994; Mintz et al., 1994) and habitat structure (Lipcius et al., 1998). Den preferences include structures having shaded cover and multiple den openings (Spanier & Zimmer-Faust, 1988), and close proximity to food (Marx & Herrnkind, 1985b). Dens provide refuge from predation (Eggleston et al., 1990, 1992; Smith & Herrnkind, 1992) and physical stresses, particularly during the time surrounding ecdysis (Lipcius & Herrnkind, 1982). The importance of shelter-induced demographic bottlenecks and post-larval supply to population abundance of early juvenile spiny lobsters is likely to vary across time and space. Nevertheless, the extremely small number of field experiments that have manipulated lobster abundance and shelter availability, as well as largescale field studies examining linkages between post-larval supply, juvenile and adult density, and habitat features, point to insufficient settlement substrate or crevicetype shelters as limiting settler and juvenile abundance in some areas (Parrish & Polovina, 1994; Butler & Herrnkind, 1997; Lipcius et al., 1997; Lipcius & Eggleston,

Ecology and Fishery Biology of Spiny Lobsters

23

submitted), rather than density-dependent mortality or food limitation (Ford et al., 1988). For example, working in macroalgal-dominated nursery areas within Florida Bay, USA, Butler & Herrnkind (1997) manipulated lobster settlement and shelter for juveniles. The number of small juvenile P. argus (<35 mm CL) increased significantly at six 0.05 ha sites where 12 artificial shelters were added, but was unchanged on three unmanipulated sites. Adding over 150 new settlers to three of the shelter-enhanced sites did not increase juvenile lobster abundance above that attributed to the original shelter enhancement. A concurrent mark±recapture study indicated that the observed increase in small lobster abundance in the shelterenhanced sites was not due to immigration. These results support the notion that local recruitment of P. argus may be increased by augmenting natural shelter with appropriately designed artificial shelters. In a related study in Florida Bay, Lipcius & Eggleston (submitted) found that abundance of P. argus increased in proportion to the numbers of artificial shelters deployed, with no change in lobster abundance over time in control sites lacking artificial shelters. Night-time band transects indicated that significantly more lobsters foraged within 1 ha sites containing artificial shelters than in control sites. Thus, lobsters did not exploit available food resources in the control areas where shelter appeared limited. Lipcius & Eggleston concluded that shelter availability was limiting the abundance of juvenile P. argus in Florida Bay seagrass and macroalgal systems. In a separate study, Lipcius et al. (1997) examined hydrodynamic decoupling of recruitment, habitat quality and adult abundance of P. argus in the central Bahamas using a habitat `source-sink' conceptual framework. Post-larval supply, juvenile density and adult abundance of P. argus were measured at four widely separated sites spanning >100 km in Exuma Sound, Bahamas. Adult abundance was lowest at a site with the highest post-larval supply and little macroalgal settlement habitat; hence, it was tentatively classified as a sink. High post-larval supply was due to a large-scale gyre that appeared to concentrate and advect post-larvae towards the nominal sink. The remaining three sites, including one marine reserve, had higher adult abundances despite lower post-larval supply, and were therefore tentatively classified as sources. It appears that some sites with suitable settlement and nursery habitat are sources of spawning stock for P. argus in Exuma Sound, whereas others with poor habitat are sinks despite sufficient postlarval influx (Lipcius et al., 1997). In Australia, Ford et al. (1988) found that lobster survival was higher on reefs where lobster densities were reduced than on control reefs; however, the caveat remains that migration rates confounded interpretation of the results. Field experiments and examination of stage-based population abundance and habitat measurements across hydrodynamically realistic spatiotemporal scales, coupled with population modelling, appear requisite to the delineation of the ecological processes regulating population size of juvenile spiny lobsters. Moreover, similar to investigations with the post-larval phase, quantitative indices based on juvenile abundance may be useful in predicting population abundance and fishery catch (Chittleborough & Phillips, 1975; Caputi & Brown, 1986; Phillips, 1986; Breen & Booth, 1989; Cruz & Phillips, 1994).

24

Spiny Lobsters: Fisheries and Culture

Adult ecology There is considerable variation in the adult segment of the life cycle among species of palinurids (Berry & Heydorn, 1970; Aiken & Waddy, 1980; Lyons et al., 1981; Cobb & Wang, 1985), particularly in the size-specific relationships between moulting, mating and egg extrusion (Lipcius, 1985; MacDiarmid, 1989a). Courtship and mating appear to be controlled to a large degree by a receptive female's choice of a suitable male partner, particularly larger individuals (Lipcius et al., 1983; Lipcius & Herrnkind, 1985) and not so much by the male's ability to force a female to copulate (Berry, 1970; Silberbauer, 1971; McKoy, 1979; Lipcius & Herrnkind, 1985). Intermale aggression also influences mate choice, whereby larger males inhibit smaller male J. edwardsii from courting females (MacDiarmid, 1989b). Mature males characteristically moult well before the mating period to be in intermoult and fully hardened in preparation for mating (Lipcius, 1985). Fertilization is external (Cobb & Wang, 1985), even in Jasus (MacDiarmid, 1988), whereby the male deposits a spermatophoric mass on the female's sternum; the structure is subsequently rasped several hours prior to spawning to release the sperm for fertilization of the eggs as they are extruded onto the abdomen and pleopods (Lipcius & Herrnkind, 1987). Egg masses are generally spawned and hatched in the spring and summer by females located in offshore reef areas (Lyons et al., 1981; MacDiarmid, 1991), although autumnal reproduction may also occur after a midsummer lull (Kanciruk & Herrnkind, 1976; Herrnkind & Lipcius, 1989). Females of many species mate some time after their moult to maturity and are, therefore, not restricted in the time available for mating. For instance, P. argus, P. cygnus and P. homarus mate from a few days to several weeks or months after moulting (Berry, 1971a, b; Morgan, 1980; Phillips et al., 1980; Lyons et al., 1981; Lipcius, 1985). There are, however, limits in that mature females about to extrude eggs do not always resorb eggs in the absence of mating, or postpone egg extrusion indefinitely (Lipcius & Herrnkind, 1985; Kittaka & MacDiarmid, 1994). In other species, such as those in the genus Jasus, mating occurs shortly after the female moults (Heydorn, 1969; Berry, 1970; Cobb & Wang, 1985; Kittaka & MacDiarmid, 1994). Some of the most novel advances in palinurid reproduction deal with the potential for sperm limitation (MacDiarmid & Butler, 1999), which offers a contrast to the long-standing belief that most lobster and crab populations are limited primarily by female reproductive output (see Fogarty, 1995). If verified, the condition of sperm limitation requires managers to assess sex-specific mortality rates and impacts upon population dynamics and stock resilience. Moreover, there are size-specific patterns in the timing of moulting and reproduction (Lipcius, 1985; MacDiarmid, 1989a, 1991). Larger adult females generally spawn eggs and release larvae earlier in the reproductive period, and produce more annual broods than smaller, adult females, which moult early in the reproductive period. Similarly, smaller adult males of many species moult early in the mating season while larger males mate rather than moult. Larger females

Ecology and Fishery Biology of Spiny Lobsters

25

produce two to four broods annually, depending on the species (e.g. Panulirus homarus produces up to four annually; Berry, 1973), whereas smaller females spawn at least once annually (Lyons et al., 1981; Lipcius, 1985). Incubation ranges from a few weeks to several months prior to release of the planktonic phyllosome larvae (Cobb & Wang, 1985). These size-specific patterns are apparently constrained by a combination of environmental and physiological factors, and potentially maximize the lifetime reproductive output of individuals (Lipcius, 1985). Environmental control of reproduction and moulting involves photoperiod and temperature, such that long daylengths and warmer temperatures enhance courtship, spawning frequencies and female gonadal development, but not aggression or male gonadal development (Lipcius & Herrnkind, 1987). Moulting rates are typically elevated by warm temperatures, but are apparently not affected significantly by photoperiod. Hatching appears to be rhythmic, with a hatching peak near sunrise for J. edwardsii (MacDiarmid, 1985). In some species, such as J. edwardsii, females form dense aggregations in areas of strong tidal water flow, probably to facilitate dispersal of newly hatched larvae (McKoy & Leachman, 1982). Shelter fidelity among spiny lobsters has been widely accepted, but little studied. Lobster movements monitored by ultrasonic telemetry or diver surveys demonstrated that lobsters have the ability to relocate a shelter or one nearby (Herrnkind et al., 1975; Cobb 1981). Only three studies have quantified the degree of shelter fidelity by tracking shelter use of several individuals over successive days (Herrnkind et al., 1975; MacDiarmid et al., 1991; Ratchford, 1999). Shelter fidelity was 42% and 38% for populations of P. argus in deep water (>10 m) in the US Virgin Islands and shallow water (1±2 m) in the central Bahamas, respectively (Herrnkind et al., 1975; Ratchford, 1999). Shelter fidelity was also 40% for J. edwardsii in New Zealand (MacDiarmid et al., 1991). Ratchford (1999) found that P. argus used three or four known shelters, moved up to 27 m among known shelters over a 4-week period, and moved 10±185 m overnight when shifting shelters. Similarly, Herrnkind et al. (1975) reported that lobsters used three or four shelters within 140 m of their study, and typically moved 30±90 m overnight. A major issue dealing predominantly with the adult phase concerns stock structure. In many species, identification of a fishery stock (i.e. a manageable segment of a population) is a relatively simple task, as in the western rock lobster, P. cygnus, which is limited by geographical boundaries and the relatively onshore± offshore orientation of coastal habitats. In contrast, other species are dispersed over diverse habitats linked to differing degrees by oceanic currents and geographic features. For instance, the Caribbean spiny lobster, P. argus, is widespread in coastal habitats from Bermuda to Brazil. Numerous currents traverse this region, as well as eddies and gyres, which may be long-lived or ephemeral (Yeung & McGowan, 1991). Previous attempts to identify stock structure in palinurids with electrophoretic techniques have met with limited success due to the relatively low levels of allozyme variation in J. edwardsii and J. novaehollandiae (Smith et al., 1980), P. marginatus (Shaklee & Samollow, 1984) and P. argus (Menzies & Kerrigan, 1979; Menzies,

26

Spiny Lobsters: Fisheries and Culture

1981). More recently, genetic variability of P. argus collected throughout the Caribbean and Florida and measured through an analysis of mitochondrial DNA was extremely low, suggesting substantial gene flow between hydrodynamically connected populations during their extended larval phase (Silberman et al., 1994). An analysis of mitochondrial DNA and the use of the polymerase chain reaction method for DNA amplification appears to be one of the most promising techniques in stock identification for palinurids, as evidenced in P. argus (Silberman et al., 1994), J. verreauxi (Brasher et al., 1992) and J. edwardsii (Ovenden et al., 1992).

Fishery ecology This chapter emphasizes an ecological approach towards attainment of an understanding of patterns and processes underlying population fluctuations in palinurids. Classical fisheries approaches (e.g. utilizing stock-recruit and yield models) have been described previously (Morgan, 1980; Cobb & Wang, 1985) and will not be emphasized here. Although emphasizing the American lobster, Homarus americanus, the comprehensive review by Fogarty (1995) serves as an excellent resource for recent and classical quantitative methods in fisheries management, including discussions of stage-based and spatially explicit models. The reader is urged to consult treatments of both approaches (i.e. ecological and stock assessment) and integrate these to achieve a thorough understanding of population dynamics in spiny lobsters. All lobster populations fluctuate substantially in abundance and at various scales in time and space (Cobb & Wang, 1985). These fluctuations result from diverse biological and physical forces acting on all life stages and in habitats ranging from shallow-water nurseries to the open ocean. The lack of understanding of the key controls of population fluctuations, both biotic and abiotic, has, in many instances, prevented us from attaining the primary goals of fisheries science, i.e. prediction of abundance, understanding sources of variation and development of effective fishery management strategies. The classical solution to these problems involves the utilization of stock-recruitment and other population dynamic models (Morgan, 1980; Cobb & Wang, 1985; Caputi, 1989; Chubb, 1994), with recent advances through the use of novel approaches such as risk analysis and spatially explicit models in a Bayesian framework (Punt & Kennedy, 1997). These analyses have yielded significant stock-recruitment models for some crustacean fisheries (Rothschild & Brunenmeister, 1984; Caputi, 1989; Lipcius & Van Engel, 1990; Chubb, 1994), although the variation about the relationships often limits their utility. However, recent advances in stock assessment methods (e.g. Punt & Kennedy, 1997) and biological techniques, such as age determination (Sheehy et al., 1998), have greatly enhanced the ability to manage palinurid fisheries effectively. The reader may refer to the references noted in the Introduction, as well as Fogarty (1995), as an entry into the world of stock assessment.

Ecology and Fishery Biology of Spiny Lobsters

27

A complementary ecological approach is needed for the determination of population fluctuations in palinurids (Paulik, 1973; Fogarty & Idoine, 1986; Rothschild, 1986; Fogarty, 1995; Botsford et al., 1997). As exemplified in the Paulik diagram of stock-recruitment relationships (Fig. 7), the influences and controlling factors of populations can occur at various life-history stages. Stochastic forces, habitat quality and density-dependent regulation are postulated jointly to control the population dynamics of palinurids. Stochastic variation, such as that due to meteorological or oceanographic processes and their resultant density-independent survival and dispersal, strongly influence early life-history stages, causing substantial variation in the survival of larvae and post-larvae (Fig. 7, Quadrant 2). Thereafter, regulatory processes such as density-dependent mortality due to predation (Fig. 7, Quadrant 4) regulate survival in the juvenile phases, as exemplified by shelter limitation in P. argus and densitydependent mortality in P. cygnus. The critical or bottleneck stages (Caddy, 1986; Caddy & Stamatopoulos, 1990) for palinurids are likely to include the early benthic and later benthic phases of juveniles, which appear to be limited to some degree by settlement substrate and larger dens or crevices, respectively. Investigations of habitat relationships must account for the influence of the seascape (Dobson et al., 1997), which includes features such as habitat fragmentation, isolation and

Fig. 7 Paulik diagram representing the various life-history phases of a palinurid lobster and the likely regulatory mechanisms of population variation. Adapted from Rothschild (1986).

28

Spiny Lobsters: Fisheries and Culture

interconnectedness. The impact of these phases, and density-dependent regulation in general, is influenced greatly by the degree of stochastic variation imposed upon the larvae and post-larvae by physical processes, such as wind-driven oceanic transport. If variation in larval and post-larval abundance is high, then density-dependent regulation may only be important at extremely high or low levels of abundance in the juvenile phase (termed density-vague control); if variation is low, then densitydependent regulation may be the most critical control of population abundance through its action upon the juvenile phase. Future experimental investigations should emphasize identification of the relative influence of stochastic, habitat-related and density-dependent processes in the life history of palinurids.

Fisheries Palinurids sustain major commercial fisheries (Table 1) while simultaneously supporting local, small-scale fisheries in remote coastal locations and islands. Capture methods for palinurids are diverse, including the use of traps, pots, skin diving, spears, SCUBA (self-contained underwater breathing apparatus) and nets of various sorts (Bowen, 1980; Phillips et al., 1980). Many palinurids form the basis for specialized fisheries, such as P. argus in the Caribbean, P. cygnus in Western Australia and Jasus in New Zealand. Other species, such as Palinurus, are caught incidentally or as part of mixed-species fisheries. Although some species are not caught in large numbers, their high market value, which characterizes most palinurids, makes their capture and sale profitable, even if only to local hotels for the tourist market. Several deep-sea species require specially outfitted vessels for their capture, in many instances precluding large-scale commercial fisheries owing to the expenses involved in location and capture. Most palinurids are caught with lobster pots or traps in relatively shallow seas, although many are also trawled over muddy or sandy bottoms. Recreational fisheries also abound, with most lobsters caught by hand or spear while skin or SCUBA diving in shallow waters.

World catch of palinurid lobsters World-wide, the average yearly catch of marine crustaceans (5 210 920 mt) constitutes about 6.0% of the landings of marine species: 87 391 320 mt (annual average for 1991±1995, FAO, 1997). The annual world catch of 212 290 mt for palinurid, nephropid, homarid and scyllarid lobsters represents approximately 4% of the annual world catch for marine crustaceans, which comprises crabs, lobsters, galatheids, shrimps, prawns, krill and miscellaneous species. The annual palinurid catch averaged 74 817 mt annually from 1991 to 1995 (Table 4), which comprised 35.2% of the world catch for lobsters. Considering other lobsters, except for galatheids, homarids constituted 34.6% of the world lobster catch, nephropids

Ecology and Fishery Biology of Spiny Lobsters

29

28.9% and scyllarids 1.3% (Table 4). Major species of exploited lobsters include the American lobster, H. americanus (70 555 mt), the Norway lobster, Nephrops norvegicus (60 013 mt), and the Caribbean spiny lobster, Panulirus argus (38 020 mt). As a contrast, the highest annual mean catches (1991±1995) for marine crabs are those of the gazami crab, Portunus trituberculatus, from the Yellow Sea, China Sea, Sea of Japan and Pacific Ocean equaling 215 149 mt; of the blue crab, Callinectes sapidus, from the Atlantic Ocean, Caribbean Sea and Gulf of Mexico, equalling 109 662 mt; and of the blue swimming crab, Portunus pelagicus, from the Pacific and Indian Oceans, equalling 57 722 mt (FAO, 1997). Most production of palinurid lobsters originates in South Africa, Australia, New Zealand, Cuba, Brazil, the USA and Mexico (Bowen, 1980). Of the commercially fished palinurid genera, Panulirus contributed 29.0% of lobster catches, Jasus 4.3% and Palinurus 3.1% (Table 4). Key species in the world palinurid catch from 1991 to 1995 included the Caribbean spiny lobster, P. argus, with 50.8%; the western rock lobster, P. cygnus, with 15.3%; the green rock lobster, J. verreauxi, with 4.9%; the red rock lobster, J. edwardsii, with 4.0%; and the Cape rock lobster, J. lalandii, with 2.8% (Table 1) (FAO, 1997).

Table 4 World catch for lobsters Mean catcha (mt)

%

Family

Genus

Palinuridae

Panulirus Jasus Palinurus

61 414 9219 4184

29.0 4.3 2.0

Subtotal:

74 817

35.3

Nephrops

60 013 1238

28.3 0.6

Subtotal

61 251

28.9

Homaridae

Homarus

73 452

34.6

Scyllaridae

Various genera

2770

1.3

Nephropidae

Total: Derived from FAO (1997). a Mean from 1991±1995.

212 290

30

Spiny Lobsters: Fisheries and Culture

Fisheries management and conservation Management of palinurid fisheries employs diverse approaches (Annala & Sullivan, 1997), ranging from input (e.g. effort) controls such as limited entry to output (e.g. catch quotas) controls such as individual transferable quotas (Table 5). The types of approach used and their effectiveness varies world-wide, as exemplified by the range of management strategies implemented in the Pacific and Indian Oceans (Table 5); similar variety in management strategies characterizes palinurid fisheries in other ocean basins. As an example of successful management, the J. edwardsii fishery off Gisborne, New Zealand, has witnessed substantial increases in catch per unit effort (CPUE) (Fig. 8a) after implementation of seasonal closures, reduction in minimum size, catch limits and temporal shifts in the timing of catches to wintertime (Breen & Kendrick, 1997). In contrast, the fishery for J. lalandii in Namibia suffered virtual collapse after both management-related and environmental perturbations (Fig. 8b). Prior to 1968, the fishery enjoyed relatively high catch rates, which may have lulled

Fig. 8 (a) CPUE of Jasus edwardsii in Gisborne, New Zealand, increased substantially after the implementation of a comprehensive management scheme in 1993. Adapted from Breen & Kendrick (1997). (b) CPUE of Jasus lalandii in Namibia decreased significantly after elimination of a minimum size limit in 1968, and further after episodic hypoxia caused mortality in 1988. Adapted from Grobler & Noli-Peard (1997).

Ecology and Fishery Biology of Spiny Lobsters

31

management into a false sense of security, resulting in elimination of the minimum size limit in 1968 (Grobler & Noli-Peard, 1997). Catch rates (CPUE) dropped substantially within 2 years, and subsequently became negligible after episodic hypoxia further drove the stock to near collapse (Fig. 8b). These contrasting situations offer an excellent lesson on the need to adopt a risk-averse approach to fishery management, and hopefully avert fishery collapse, which sometimes results from the joint effects of overexploitation and poor environmental conditions. In an earlier treatment (Lipcius & Cobb, 1994), the following were deemed reasonable guidelines for the management of spiny lobster fisheries (Bowen, 1980; Brown & Caputi, 1986; Lyons, 1986): (1) accurate catch-effort and length-frequency data are required for sound regulation; (2) restrictions upon catch and effort through size limits, catch quotas or seasons, and limited or delayed entry should be mandated and enforceable to be effective; (3) development of accurate recruitment indices (e.g. Western rock lobster fishery) based on long-term post-larval or juvenile abundance data sets appears successful in projecting catch levels in subsequent years (Caputi & Brown, 1986; Phillips, 1986); and (4) there needs to be a communication network involving fishermen, industry, management and the research community. In addition to the measures described earlier (Table 5), a risk-averse approach is central to Table 5 Management strategies used with various spiny lobster fisheries Region Management strategy

India

South Africa

West Australia

New Zealand

Input controls Limited entry Vessel size Gear restrictions Pot limits Escapement gaps Closed areas Closed seasons Minimum legal size Condition Maximum legal size Output controls

* * *

* *

Total allowable catch Individual transferable quota Bag limits (recreational) Adapted from Annala & Sullivan (1997).

* *

* * * *

* *

* *

* * * *

*

* *

*

* * *

32

Spiny Lobsters: Fisheries and Culture

successful fishery management, a combination of effective fishery management strategies and comprehensive research investigations is required (e.g. Breen & Kendrick, 1997; Pitcher et al., 1997), and the use of closed areas (e.g. marine reserves; Childress, 1997) should be considered as a valuable tool where other effort and catch controls have had limited success. Such measures are essential to the sustainable resource use of palinurids in the face of the growing threats due to anthropogenic global environmental change.

References Ache, B.W. & Macmillan, D.L. (1980) Neurobiology. In The Biology and Management of Lobsters, Vol. I (Ed. by J.S. Cobb & B.F. Phillips), pp. 165±213. Academic Press, New York, USA. Acosta, C.A. & Butler, M.J. (1997) Role of mangrove habitat as a nursery for juvenile spiny lobster, Panulirus argus, in Belize. Mar. Freshwat. Res., 48, 721±8. Acosta, C.A., Matthews, T.R. & Butler, M.J. (1997) Temporal patterns and transport processes in recruitment of spiny lobster (Panulirus argus) postlarvae to south Florida. Mar. Biol., 129, 79±85. Aiken, D.E. & Waddy, S.L. (1980) Reproductive biology. In The Biology and Management of Lobsters, Vol. I (Ed. by J.S. Cobb & B.F. Phillips), pp. 215±76. Academic Press, New York, USA. Andree, S.W. (1981) Locomotory activity patterns and food items of benthic post-larval spiny lobsters, Panulirus argus. M.S. thesis, Florida State University, Tallahassee, USA. Annala, J.H. & Sullivan, K.J. (1997) Management strategies in lobster fisheries: report from a workshop. Mar. Freshwat. Res., 48, 1081±4. Bannerot, S.P., Ryther, J.H. & Griffith, S. (1991) Progress on assessment of recruitment of postlarval spiny lobsters, Panulirus argus, to Antigua, West Indies. Gulf Carib. Fish. Inst. Proc., 40, 482±8. Barkai, A. & McQuaid, C. (1988) Predator±prey role reversal in a marine benthic ecosystem. Science, 242, 62±4. Berrill, M. (1975) Gregarious behavior of juveniles of the spiny lobster, Panulirus argus (Crustacea: Decapoda). Bull. Mar. Sci., 25, 515±22. Berry, P.F. (1970) Mating behavior, oviposition and fertilization in the spiny lobster Panulirus homarus (L.). S. Afr. Oceanogr. Res. Inst., Invest. Rep., 24, 1±16. Berry, P.F. (1971a) The spiny lobsters (Palinuridae) of the east coast of southern Africa. Distribution and ecological notes. S. Afr. Oceanogr. Res. Inst., Invest. Rep., 27, 1±23. Berry, P.F. (1971b) The biology of the spiny lobster Panulirus homarus (Linnaeus) off the east coast of southern Africa. S. Afr. Oceanogr. Res. Inst., Invest. Rep., 28, 1±75. Berry, P.F. (1973) The biology of the spiny lobster Panulirus delagoae Barnard, off the coast of Natal, South Africa. S. Afr. Oceanogr. Res. Inst., Invest. Rep., 31, 1±27. Berry, P.F. & Heydorn, A.E.F. (1970) A comparison of the spermatophoric masses and mechanisms of fertilization in southern African spiny lobsters (Palinuridae). S. Afr. Oceanogr. Res. Inst., Invest. Rep., 25, 1±18. Berry, P.F. & Smale, M.J. (1980) An estimate of production and consumption rates in the spiny lobster Panulirus homarus on a shallow littoral reef off the Natal coast, South Africa. Mar. Ecol. Prog. Ser., 2, 337±43. Booth, J.D. (1979) Settlement of the rock lobster, Jasus edwardsii (Decapoda: Palinuridae), at Castlepoint, New Zealand. N.Z. J. Mar. Freshwat. Res., 13, 395±406.

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Parker, K.P. (1972) Recruitment and behavior of puerulus larvae and juveniles of the California spiny lobster, Panulirus interruptus (Randall). M.S. thesis, San Diego State University, San Diego, CA, USA. Parrish, F.A. & Polovina, J.J. (1994) Habitat thresholds and bottlenecks in production of the spiny lobster (Panulirus marginatus). Bull. Mar. Sci., 54, 151±63. Paulik, G.J. (1973) Studies of the possible form of the stock-recruitment curve. Rapp. Proc.-Verb. Reun., 164, 302±15. Pearce, A.F. & Phillips, B.F. (1988) ENSO events, the Leeuwin Current, and larval recruitment of the western rock lobster. J. Cons. Int. Explor. Mer., 45, 13±21. Phillips, B.F. (1972) A semi-quantitative collector of the puerulus larvae of the western rock lobster Panulirus longipes cygnus George (Decapoda, Palinuridae). Crustaceana, 22, 147±54. Phillips, B.F. (1981) The circulation of the southeastern Indian Ocean and the planktonic life of the western rock lobster. Oceanogr. Mar. Biol. Ann. Rev., 19, 11±39. Phillips, B.F. (1983) Migrations of pre-adult western rock lobsters, Panulirus cygnus, in Western Australia. Mar. Biol., 76, 311±18. Phillips, B.F. (1986) Prediction of commercial catches of the western rock lobster Panulirus cygnus. Can. J. Fish. Aquat. Sci., 43, 2126±30. Phillips, B.F. (1990) Estimating the density and mortality of juvenile western rock lobsters (Panulirus cygnus) in nursery reefs. Can. J. Fish. Aquat. Sci., 47, 1330±8. Phillips, B.F., Brown, P.A., Rimmer, D.W. & Reid, D.D. (1979) Distribution and dispersal of the phyllosoma larvae of the western rock lobster Panulirus cygnus in the southeastern Indian ocean. Aust. J. Mar. Freshwat. Res., 20, 773±83. Phillips, B.F., Cobb, J.S. & George, R.W. (1980) General biology. In The Biology and Management of Lobsters, Vol. I (Ed. by J.S. Cobb & B.F. Phillips), pp. 1±82. Academic Press, New York, USA. Phillips, B.F., Cruz, R., Brown, R.S. & Caputi, N. (1994a) Predicting the catch of spiny lobster fisheries. In Spiny Lobster Management (Ed. by B.F. Phillips, J.S. Cobb & J. Kittaka), pp. 285± 301. Blackwell Scientific Publications, Cambridge, MA, USA. Phillips, B.F. & Macmillan, D.L. (1987) Antennal receptors in puerulus and postpuerulus stages of the rock lobster Panulirus cygnus (Decapoda: Palinuridae) and their potential role in puerulus navigation. J. Crust. Biol., 7, 122±35. Phillips, B.F. & McWilliam, P.S. (1986) The pelagic phase of spiny lobster development. Can. J. Fish. Aquat. Sci., 43, 2153±63. Phillips, B.F. & Olsen, L. (1975) Swimming behaviour of the puerulus larvae of the western rock lobster. Aust. J. Mar. Freshwat. Res., 26, 415±17. Phillips, B.F., Pearce, A.F., Litchfield, R. & Guzman del ProÂo, S.A. (1994b) Spiny lobster catches and the ocean environment. In Spiny Lobster Management (Ed. by B.F. Phillips, J.S. Cobb & J. Kittaka), pp. 250±61. Blackwell Scientific Publications, Cambridge, MA, USA. Phillips, B.F. & Sastry, A.N. (1980) Larval ecology. In The Biology and Management of Lobsters, Vol. II (Ed. by J.S. Cobb & B.F. Phillips), pp. 11±57. Academic Press, New York, USA. Pitcher, C.R., Dennis, D.M. & Skewes, T.D. (1997) Fishery-independent surveys and stock assessment of Panulirus ornatus in Torres Strait. Mar. Freshwat. Res., 48, 1059±68. Pollock, D.E. (1978) Growth and production rates of the rock lobster Jasus lalandii (H. MilneEdwards). Ph.D. thesis, University of Witwatersrand, South Africa. Pollock, D.E. (1990) Paleoceanography and speciation in the spiny lobster genus Jasus. Bull. Mar. Sci., 46, 387±405. Pollock, D.E. (1992) Paleoceanography and speciation in the spiny lobster genus Panulirus in the Indo-Pacific. Bull. Mar. Sci., 51, 135±46. Pollock, D.E. (1993) Speciation in spiny lobsters ± clues to climatically-induced changes in ocean circulation patterns. Bull. Mar. Sci., 53, 937±44.

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Punt, A.E. & Kennedy, R.B. (1997) Population modelling of Tasmanian rock lobster, Jasus edwardsii. Mar. Freshwat. Res., 48, 967±80. Ratchford, S.G. & Eggleston, D.B. (1998) Size- and scale-dependent chemical attraction contribute to an ontogenetic shift in sociality. Anim. Behav., 56, 1027±34. Rimmer, D.W. & Phillips, B.F. (1979) Diurnal migration and vertical distribution of phyllosoma larvae of the western rock lobster, Panulirus cygnus George. Mar. Biol., 54, 109±24. Rothschild, B.J. (1986) Dynamics of Marine Fish Populations, 277 pp. Harvard University Press, Cambridge, MA, USA. Rothschild, B.J. & Brunenmeister, S.L. (1984) The dynamics and management of shrimp on the northern Gulf of Mexico. In Penaeid Shrimps ± Their Biology and Management (Ed. by D.A. Gulland & B.J. Rothschild), pp. 145±72. Fishing News Books, Farnham, UK. Sastry, A.N. (1983a) Pelagic larval ecology and development. In The Biology of Crustacea, Vol. 7 (Ed. by F.J. Vernberg & W.B. Vernberg), pp. 213±82. Academic Press, New York, USA. Sastry, A.N. (1983b) Ecological aspects of reproduction. In The Biology of Crustacea, Vol. 7 (Ed. by F.J. Vernberg & W.B. Vernberg), pp. 179±270. Academic Press, New York, USA. Serfling, S.A. (1972) Recruitment, habitat preference, abundance and growth of the puerulus and early juvenile stages of the California spiny lobster, Panulirus interruptus (Randall). M.S. thesis, San Diego State University, San Diego, CA, USA. Serfling, S.A. & Ford, R.F. (1975) Ecological studies of the puerulus larval stage of the California spiny lobster Panulirus interruptus Randall. Fish. Bull., U.S., 73, 360±77. Shaklee, J.B. & Samollow, P.B. (1984) Genetic variation and population structure in a spiny lobster, Panulirus marginatus, in the Hawaiian archipelago. Fish. Bull., U.S., 82, 693±702. Sheehy, M., Caputi, N., Chubb, C. & Belchier, M. (1998) Use of lipofuscin for resolving cohorts of western rock lobster (Panulirus cygnus). Can. J. Fish. Aquat. Sci., 55, 925±36. Silberbauer, B.I. (1971) The biology of the South African rock lobster Jasus lalandii (H. MilneEdwards). 1. Development. S. Afr. Div. Sea Fish., Invest. Rep., 92, 1±70. Smith, K.N. & Herrnkind, W.F. (1992) Predation on early juvenile spiny lobsters Panulirus argus (Latreille): influence of size and shelter. J. Exp. Mar. Biol. Ecol., 157, 3±18. Smith, P.J., McKoy, J.L. & Machin, P.J. (1980) Genetic variation in the rock lobsters Jasus edwardsii and Jasus novaehollandiae. N.Z. J. Mar. Freshwat. Res., 14, 55±63. Spanier, E. & Zimmer-Faust, R.K. (1988) Some physical properties of shelter that influence den preference in spiny lobsters. J. Exp. Mar. Biol. Ecol., 121, 137±49. Street, R.J. (1971) Rock lobster migration off Otago. N.Z. Comm. Fish., June,16±17. Tegner, M.J. & Levin, L.A. (1983) Spiny lobsters and sea urchins: analysis of a predator-prey interaction. J. Exp. Mar. Biol. Ecol., 73, 125±50. Trendall, J. & Bell, S. (1989) Variable patterns of den habitation by the ornate rock lobster, Panulirus ornatus, in the Torres Strait. Bull. Mar. Sci., 45, 564±73. White, A. (1847) List of the specimens of Crustacea in the collection of the British Museum. i±viii, 1±143. Williams, A.B. (1986) Lobsters ± identification, world distribution, and U.S. trade. Mar. Fish. Rev., 48, 1±36. Williams, A.B. (1988) Lobsters of the World ± An Illustrated Guide, 186 pp. Osprey Books, Huntington, NY, USA. Williams, B.G. & Dean, I.C. (1989) Timing of locomotor activity in the New Zealand rock lobster, Jasus edwardsii. N.Z. J. Mar. Freshwat. Res., 23, 215±24. Witham, R.R., Ingle, R.M. & Joyce, E.A., Jr (1968) Physiological and ecological studies of Panulirus argus from the St. Lucie estuary. Fla. Bd. Cons. Tech. Ser., 53, 1±31. Yeung, C. & McGowan, M.F. (1991) Differences in inshore-offshore and vertical distribution of phyllosoma larvae of Panulirus, Scyllarus and Scyllarides in the Florida Keys in May±June, 1989. Bull. Mar. Sci., 49, 699±714.

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Yoshimura, T. & Yamakawa, H. (1988) Microhabitat and behavior of settled pueruli and juveniles of the Japanese spiny lobster Panulirus japonicus at Kominato, Japan. J. Crust. Biol., 8, 524±31. Zimmer-Faust, R.K. (1991) Chemical signal-to-noise detection by spiny lobsters. Biol. Bull., 181, 419±26. Zimmer-Faust, R.K. & Case, J.F. (1982) Odors influencing foraging behavior of the California spiny lobster, Panulirus interruptus, and other decapod Crustacea. Mar. Behav. Physiol., 9, 35± 58. Zimmer-Faust, R.K. & Case, J.F. (1983) A proposed dual role of odor in foraging by the California spiny lobster, Panulirus interruptus (Randall). Biol. Bull., 164, 341±53. Zimmer-Faust, R.K. & Spanier, E. (1987) Gregariousness and sociality in spiny lobsters: implications for den habitation. J. Exp. Mar. Biol. Ecol., 105, 57±71. Zimmer-Faust, R.K., Tyre, J.E. & Case, J.F. (1985) Chemical attraction causing aggregation in the spiny lobster, Panulirus interruptus (Randall), and its probable ecological significance. Biol. Bull., 169, 106±18.

Part 1 Fisheries: Methods, Management and Status

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 1

The Status of Australia's Rock Lobster Fisheries B.F. PHILLIPS Curtin University of Technology, P.O. Box 1987, Perth, Western Australia 6845, Australia

C.F. CHUBB and R. MELVILLE-SMITH Bernard Bowen Fisheries Research Institute, Western Australian Marine Research Laboratories, P.O. Box 20, North Beach 6020, Western Australia, Australia

1.1

Introduction

Seven Panulirus and Jasus rock lobster species are found in Australian waters, four of which support significant commercial and recreational fisheries. Panulirus cygnus is found on the lower west coast, Panulirus ornatus in northern Australia, particularly the Torres Strait and far north Queensland, Jasus edwardsii (formerly J. novaehollandiae) in southern Australia: South Australia, Victoria and Tasmania, and Jasus verreauxi on the central east coast, New South Wales (Fig. 1.1). The commercial whole weight catches of the four species were P. cygnus 13 600 t, P. ornatus 460 t (1990), J. edwardsii 4730 t (1997/98) and J. verreauxi 150 t (1997/ 98), giving a total of about 18 900 t, making Australia's rock lobster production the largest in the world. This chapter summarizes the level of knowledge on the four important commercial species and the status of each of the stocks. 1.2

The tropical rock lobster P. ornatus in the Torres Strait

The fishery for P. ornatus in the Torres Strait is reserved for exploitation by the traditional inhabitants of Torres Strait and is the basis of their most important commercial fishery. First assessments of the stocks showed that exploitation was low and it was recommended that increased involvement by Islander divers could be encouraged. However, lower recruitment and increased fishing mortality have now indicated that new management measures may, in future, need to be considered to address uncapped effort potential in the fishery (Pitcher et al., 1997). 1.2.1

Distribution and life history

Panulirus ornatus is widely distributed throughout the Indo-West Pacific and around the northern Australian coast, the Torres Strait and southern coast of Papua New Guinea (George, 1968, 1972), and prefers calm turbid waters (George, 1968). Most 45

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Spiny Lobsters: Fisheries and Culture

Fig. 1.1

The main distribution of Australian rock lobster species.

research has been undertaken in the Torres Strait region, where a commercial fishery for this species operates (Fig. 1.2). As with all Panulirus species, P. ornatus has a relatively long larval phase (estimated to be 6 months) in the open ocean before the puerulus stage settles into small holes and crevices in the reefs and seabed. Growth is rapid with animals attaining the minimum 100 mm tail length (80 mm carapace) about 1 year after settling (1.5 years old). When P. ornatus is about 2.5 years old (2 years after settlement) there is a synchronized moult in August±October and virtually all the females and the majority of the males migrate north-east into the Gulf of Papua

The Status of Australia's Rock Lobster Fisheries

Fig. 1.2

47

Detail of the Torres Strait and the migration of Panulirus ornatus.

(Pitcher, 1991). Just before or during the migration the lobsters undergo reproductive development and large numbers finally arrive on the breeding grounds of the coastal reefs of the eastern Gulf of Papua (Fig. 1.2), while others probably migrate further east to the reefs at the northern end of the Great Barrier Reef (Pitcher, 1991). The females move offshore from the breeding grounds to release their eggs and then move back inshore again. The larvae are thought to become entrained in an ocean gyre in the north-west Coral Sea that could distribute the larvae back into the Torres Strait (Pitcher, 1991). It is not known how important the larval contribution of the breeding populations of the northern Great Barrier Reef and north-east Queensland coast is to overall recruitment. However, these populations are mainly in deep water (75 m), beyond the access of the commercial dive fishery (Pitcher, 1991). There is evidence that the post-migration breeding lobsters at Yule Island (Fig. 1.2) are in very poor physical condition and there is virtually total mortality of postspawning animals (Pitcher et al., 1991). This means that the level of puerulus settlement on the fishing grounds each year may depend on the success of the previous year's migration and breeding (Pitcher, 1991).

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Spiny Lobsters: Fisheries and Culture

1.2.2

History of the fishery

There has been an artisanal fishery on P. ornatus in the Torres Strait and the east coast of Papua New Guinea for hundreds of years. Commercial fishing began in the area in the late 1960s and is restricted to the indigenous Torres Strait Islander people, who derive from it a significant portion of their income (Channells, 1986). Diving is the method of fishing, with fishers free diving (1±4 m depth) or using hookah (4±15 m depth) from small outboard powered dinghies and returning their catches to land-based processors or processing vessels. There are 277 licensed boats in the fishery. Twelve small mobile freezer vessels also operate in the fishery, acting as mother ships for teams of divers. The lobsters were originally sold as tails on the Australian and overseas (mainly USA) markets (Channells, 1986). However, a market has now developed for live lobsters in Asia. Island communities operate 300±400 dinghies throughout the fishery, with the principal fishing grounds being around Thursday Island, Orman Reef and Warrior Reefs (Fig. 1.2), which are the areas most accessible to the major population centres. Fishing occurs year round, with peak catches coming in March±August and little fishing activity during October±December (Pitcher, 1991). Catches (whole weight assuming a 40% tail weight recovery) from Torres Strait have varied from 170 to 310 t between 1970 and 1980. Catches peaked in 1986 at 875 t but were between 375 and 625 t from 1987 to 1991 (Fig. 1.3). Recruitment to the fishery varies considerably, and the estimated catch in 1999 is only 159 t (CSIRO, 1999).

1.2.3

Management controls

Management of the stock is affected by a minimum legal size of 100 mm tail length or an 80 mm carapace length measurement. There are no controls on fishing effort

Fig. 1.3

Torres Strait Panulirus ornatus catch (whole weight) from 1978 to 1998.

The Status of Australia's Rock Lobster Fisheries

49

per se, but with access now limited to Torres Strait Islanders, it is unlikely that there would be a large expansion in the number of fishers. The only other source of fishing effort was trawlers that targeted the spawning migration in the Gulf of Papua. Trawling was banned in 1984. The fishery is managed under a treaty (Article 22) between Australia and Papua New Guinea as the Torres Strait Protection Zone, in which the traditional way of life and livelihood of the inhabitants is to be protected (Anon., 1992a). 1.2.4

Status of the stock

Since 1989 the abundance of P. ornatus over the approximate 25 000 square km of the Torres Strait fishery was estimated by using a dive/transect technique (Pitcher et al., 1992, 1997). Panurilus ornatus was found throughout the area, except in the centre of the fishery where the habitat is unsuitable silt and mud. Densities varied from two to over 100 animals per hectare. It was estimated that there are 11±17 million lobsters in the Torres Strait, with about 8 million being legal size (Pitcher, 1991; Pitcher et al., 1992). The annual fishery-independent surveys of the relative stock abundance, and catch sampling, have contributed to the development of a simple cohort dynamics model of the fishery for a range of fishing mortalities. It estimates the potential yield 1 year in advance ± information valuable for managers considering development options and negotiating catch-sharing agreements and access rights (Pitcher et al., 1997). It has been estimated that the long-term potential yield from the fishery could be 730 t (Anon., 1998a). However, the low catches in the last few years may require a review of this assessment. 1.2.5

Future research

Puerulus collectors (Phillips, 1972) are being tested to see whether they offer a suitable method for an even earlier assessment of recruitment to the fishery, as has been used for the western rock lobster (Caputi et al., 1995). Ecological studies on the early juveniles, growth and mortality will be undertaken to expand the general understanding of the species and the impact of fishing (Pitcher, 1991). Future research will develop the model by incorporating information from ongoing surveys, catch recording and logbook data from Australia and Papua New Guinea fisheries (Pitcher et al., 1997).

1.3

The eastern rock lobster Jasus verreauxi of New South Wales

Although the New South Wales rock lobster J. verreauxi catch is small (reported commercial catch approximately 100 t), it forms the basis of an important fishery.

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Spiny Lobsters: Fisheries and Culture

The eastern rock lobster is considered the premier seafood of New South Wales, enjoying a high public profile, and fetching substantially higher prices than rock lobsters imported from other Australian states.

1.3.1

Distribution and life history

Jasus verreauxi is found along the entire New South Wales coast (Fig. 1.4), from inshore to the edge of the continental shelf (200 m depth). Mating takes place in spring and early summer and females carry eggs between September and January. The average size of mature females is approximately 167 mm carapace length (CL) and they have an estimated age of about 8 years (Montgomery, 1991; Anon., 1992b). The breeding stock is found predominantly in the northern sector of the fishery (i.e. north of Port Stephens, Fig. 1.4), in water deeper than 50 m (Montgomery, pers. comm.).

Fig. 1.4

Movement of Jasus verreauxi along the New South Wales coast.

The Status of Australia's Rock Lobster Fisheries

51

The larval stage lasts for approximately 9 months before the puerulus stage settles on the inshore reefs and the benthic juvenile phase is commenced. J. verreauxi takes about 3±5 years from hatching to reach the legal minimum size of 104 mm CL. The animals are 6±7 years old before sexual maturity is attained. For animals around the legal size, 2±3 moults take place each year with carapace increments of about 6±7 mm each time (Anon., 1992b). Montgomery (pers. comm.) has hypothesized that there is a general movement of premature animals from the juvenile inshore areas to the deep-water breeding grounds and that lobsters from the southern section of the fishery undertake a prebreeding migration to the northern end of the species' distribution where the bulk of the breeding population is situated (Fig. 1.4). This migration takes place when the animals are about 4±5 years old. Once in the northern end of the distributional range, lobsters move seasonally to the edge of the Continental Shelf probably to mate, and then return to shallow inshore reefs to spawn. Further research needs to be undertaken to verify the extent of the movement and migration of J. verreauxi.

1.3.2

History of the fishery

Jasus verreauxi has been fished in New South Wales since 1873. Reported catches peaked at nearly 400 t in the late 1920s, before dropping off in the 1930s and early 1940s (Fig. 1.5). A resurgence in landings took place in post-World War II years when many returned servicemen entered the general New South Wales fishing industry. Landings peaked once again at around 400 t in the late 1940s and early 1950s, but have since declined to an average of between 100 and 200 t, worth approximately $4.0 million per annum (Anon., 1998b). The fishery was initially focused inshore and in the northern sector from Crowdy Head to Coffs Harbour (Fig. 1.4). Fishermen used small boats to set traps around headlands and shallow reefs. In 1969, populations were discovered offshore from Sydney in deep water and the fishery expanded offshore (170±200 m depth) and southward from the ports of Ulladulla and Batemans Bay. The fishery has undergone significant changes in management since the early 1990s, with limited access introduced in 1992 and the introduction of a total allowable commercial catch (TACC) in 1994 (Montgomery et al., 1996).

1.3.3

Management controls

Controls in the fishery include a minimum legal size of 104 mm CL, a maximum legal size of 200 mm, a ban on the taking of egg-bearing females, restrictions on trap dimensions, restriction of the mesh size on traps to 50 mm and individual catch quotas (Montgomery et al., 1996). Recreational fishers are restricted to a bag limit of two per day and are allowed to use only one trap, or dive and capture with their

52

Spiny Lobsters: Fisheries and Culture

Fig. 1.5 New South Wales Jasus verreauxi catch in tonnes whole weight from 1884 to 1998 after Liggins et al. (1999). The landings include estimates of unreported commercial and recreational catches.

hands, without the use of compressed air. These regulations confine the recreational fishery to shallow inshore waters, although this was not the intention of their introduction (Montgomery, pers. comm.). There is no closed season (Anon., 1997a).

1.3.4

Status of the stock

Catch rates have been in decline over most of the life of the fishery, but stabilized in the early 1990s (Montgomery, 1995) and have increased since 1993/94 when a TACC was introduced (Anon., 1998a). It is considered that substantial quantities of the commercial catch went unreported in earlier years (Fig. 1.5), as many sales were made by commercial fishermen direct to restaurants and retail outlets and these went unrecorded. It is suggested (Montgomery et al., 1997), that catch and effort reporting by commercial fishermen has been more honest since the introduction of a TACC. A biomass dynamics model developed for the fishery (Montgomery et al., 1998) has suggested that there was a decline in biomass over most years between 1900 and 1993/94, but it has increased since then. The same assessment suggests that the unexploited biomass is likely to range around 36±41% of the biomass of the exploitable virgin stock. Most future scenarios for the fishery based on modelling

The Status of Australia's Rock Lobster Fisheries

53

predictions suggest that TACCs of up to 150 t will result in an increase in stock biomass early into the twenty-first century (Montgomery et al., 1997). TACCs were set at 125 t in 1998/99 and were raised to 140 t in 1999/2000 (Montgomery pers. comm.). Of concern in this fishery is the depleted level of the spawning stock. The legal minimum size of 104 mm CL is well below 166 mm CL, the size at which the animals are first considered to breed (Montgomery, 1992). Length±frequency sampling (Montgomery, 1995) showed that only 10% of animals sampled in the commercial catch were larger than size at first breeding and that more than 64% of the annual total landings came from areas where only immature animals were sampled. It is suggested that the spawning stock may be as low as 3% of the exploitable unfished biomass (Montgomery et al., 1997). Puerulus collectors have been developed and deployed in this fishery since 1992 (Montgomery & Kittaka, 1994; Montgomery et al., 1996). The pattern of settlement has been shown, based on six sampling sites, to be highest in the central and southern part of the grounds between Sydney and Eden (Montgomery et al., 1997). The same study has shown that there are significant interannual differences between sampling sites. These data will form the baseline of a time series that may eventually provide an index of recruitment to the fishery. Another time series that may provide information in the future on the state of the brood stock as well as recruitment to the fishery, is a fishery-independent trapping survey that was initiated in 1995 (Montgomery et al., 1996, 1997). The number of recreational fishers has yet to be accurately established, but it has been suggested that possibly 60 000 people participated in this pastime in the 1996/ 97 season (Montgomery et al., 1997). A survey of recreational abalone divers, which picked up catches made by recreational lobster fishers as a by-product (Andrew et al., 1997), estimated that that group landed around 26 t of lobsters in the 1997 season.

1.3.5

Future research

An important future objective is to develop a length-based model for the fishery. Before this objective can be met, it will be necessary to collect additional information on the sizes of lobsters in the population, the size of the spawning biomass, growth and movement (Montgomery et al., 1997). Work on improving knowledge in these areas is underway.

1.3.6

Future management

The objective of management of the eastern rock lobster fishery as stated in the draft management plan is to increase the stock biomass (Montgomery et al., 1997). Based

54

Spiny Lobsters: Fisheries and Culture

on model outputs, Montgomery et al. (1997), all indications are that this objective will be achieved by the TACCs that have been set since the 1993/94 season.

1.3.7

Summary

Jasus verreauxi on the New South Wales coast is assessed to have been heavily exploited in the past. The current management strategy is aimed at rebuilding the depleted stocks and early results suggest that this initiative has achieved some success.

The southern rock lobster Jasus edwardsii (formerly known as Jasus novaehollandiae)

1.4

Jasus edwardsii has the widest distribution of any of the rock lobster species in Australia. The species supports significant commercial fisheries in South Australia, Tasmania, Victoria and southern Western Australia, with an insignificant amount taken in southern New South Wales (Fig. 1.1).

1.4.1

Distribution and life history

Jasus edwardsii is distributed around southern mainland Australia, Tasmania and New Zealand. In Australia, specimens have been found as far north as Geraldton in Western Australia (28 450 s, 114 070 E) and Coffs Harbour in northern New South Wales (30 180 S, 153 080 E), with the bulk of the population being on the coast of South Australia, Tasmania and southern Victoria from depths of 1±200 m (Figs. 1.1, 1.6). A small population is also found on the south coast of Western Australia east of 115 S. From morphological and genetic work (Booth et al., 1990, Ovenden et al., 1991), the Australian populations and those of New Zealand are the same stocks. Females are fertilized externally by the male depositing a spermatophore on their sternal plates (MacDiarmid, 1988) between April and July. The females carry eggs on the underside of their abdomen (tail) until hatching, which peaks in October. The larger the female the larger the number of eggs they carry (e.g. around 150 000 to over 640 000 eggs for females with a 97 mm and 150 mm carapace, respectively (Hobday & Ryan, 1997). The eggs hatch to a naupliosoma larvae that moults after about 12 h to the first phyllosoma stage. Puerulus settlement studies suggest that the phyllosoma may spend 8±22 months at sea prior to settlement (Kennedy, 1990; Booth, 1994), during which time they would become widely distributed in the southern ocean (Winstanley, 1977). The size at which 50% of the females breed varies considerably across the animal's range (Table 1.1). Females appear to reach sexual maturity (Table 1.1) at about 4

The Status of Australia's Rock Lobster Fisheries Table 1.1

55

Size of maturity of Jasus edwardsii in Australia

Location (Fig. 1.1)

Carapace length (mm) at which 50% of females mature

Western South Australiaa South-eastern South Australia Western Victoriab Eastern Victoriab King Island (Tasmania)c Southern Tasmaniac

100±114 a

88±96 90 112 115 <65

Sources: aPrescott (pers. comm), bHobday & Ryan (1997), cKennedy (1989).

years of age in one area of Tasmania and at 3.5±5.5 years in South Australia (Prescott, pers. comm.). Breeding animals are found throughout the entire range in the deeper offshore waters. Growth rates vary considerably from location to location throughout the range. For example, an animal with a 90 mm carapace can have an annual growth of 1±20 mm depending on its location and sex (Kennedy, pers. comm.). Depth is also an important determinant of growth increment. McGarvey et al. (1999) have shown that growth rates of lobsters >100 mm decline by approximately 1 mm/year for every 20 m increase in depth of habitat, at depths of 20 m and greater. Males and females have similar growth rates until the females reach sexual maturity and their growth rate slows (McGarvey et al., 1999).

1.4.2

History of the fishery

The catches of J. edwardsii reflect the distribution of the main part of the stock in South Australia, Tasmania and Victoria. Fishers use baited traps that they usually pull daily depending on weather and catch rates. In Tasmania, in waters deeper than 40 m, fishing is sometimes conducted during the day as well as at night during certain times of the season (i.e. traps are pulled more than once per day). In South Australia J. edwardsii was captured for domestic consumption as early as 1870. However, it was not until the introduction of freezer shipments to the USA in the late 1940s that commercial exploitation began in earnest. The growth of the fishery and changes in the distribution of fishing were most rapid between the late 1940s and 1966/67 (Copes, 1978). Fishing effort in 1949/50 was 109 000 pot lifts and by 1966/67 had escalated to 3 152 000 pot lifts; however, the catch had only increased from 1135 t to 2837 t over the same period (Copes, 1978; Staniford, 1986). This pattern of development is typical of that which occurred in the rock lobster fisheries in the other states (Victoria and Tasmania) and for P. cygnus in Western

56

Spiny Lobsters: Fisheries and Culture

Australia. Initially, there was strong growth in catch from the fishery and high catch rates; however, these declined sharply as the number of vessels and traps used in the fishery increased rapidly. The spectacular decline in catch rates in South Australia from 10.4 kg per trap lift in 1949/50 to 0.9 kg per trap lift in 1966/67 focused industry's and government's attention on the need to restrict further entry to the fishery. In 1967, the fishery became limited entry, no additional entrants were allowed and the number of traps used per vessel was restricted (Copes, 1978; Staniford, 1986). The fishery was divided into two management zones: a southern zone, from the Victorian border to the mouth of the Murray River, and a northern zone, from the mouth of the Murray River to the Western Australian border (Fig. 1.6). In the 1993/94 season the southern zone moved to TACC management system with individual transferable quotas. The northern zone has retained the effort-controlled management system, but has introduced a system of voluntary time closures to compensate for increases in effective fishing effort resulting from improved fishing efficiency. Both management systems appear to be working efficiently. Currently there are 183 boats and 11 923 traps in the southern zone and 71 boats and 3950 traps in the northern zone (Table 1.2). About 65% of the approximately 2500 t catch is taken in the southern zone. Because the grounds in the northern zone of the fishery are scattered over a wider area than in the southern zone, fishermen undertake fishing trips of several days to a week's duration, keeping their catch in live wells on their boats. In the southern zone virtually all fishing is day trips, although depending on catch rates and weather conditions, traps may not be pulled for 2±3 days. There are also about 6200 licensed recreational fishers in South Australia using up to two traps per person per day for a bag limit of four lobsters per person per day. Table 1.2 Number of boats and traps and maximum number of traps permitted to be fished per boat in the limited entry Jasus edwardsii fisheries in Western Australia (WA), South Australia (SA), Tasmania, Victoria and New South Wales (NSW) Location

Numbers of boats (entitlements)

WA (Esperance zone) WA (outer zones) SAa (S zone)

11 31 183

SAa (N zone) Tasmaniab Victoriac (E zone) (W zone) NSWd

71 314 69 90 177

Total number of traps

Maximum traps per boat

Minimum traps

568 3860 11 923

90 Unlimited 80

30 ± 40

3950 10 505 2615 5388 Unlimited

60 50 60 Unlimited Unlimited

25 15 15 10 ±

Source: aPrescott (pers. comm.), bKennedy & Gardner (pers. comm.), cMolloy, Hobday & Flint (pers. comm.), dMontgomery (pers. comm.).

The Status of Australia's Rock Lobster Fisheries

57

Unlicensed recreational fishers are permitted to use up to three hoop nets or dive for up to four rock lobsters per day. Recreational trap fishermen were estimated to have taken 62 t of lobsters in 1991±92. (Prescott, pers. comm.) In Tasmania and Victoria the fishery for J. edwardsii developed along similar lines to that in South Australia, with a small fishery initially providing product for a limited local market. In 1882, Tasmania introduced its first management regulations for the fishery: season closures (Kennedy, 1989) and size limits (currently 110 mm and 105 mm CL for males and females, respectively). In 1926, limits were put on the number of traps that a boat could use. With the rapid expansion of the fishery after 1945, Tasmania introduced limited entry in 1967 to maintain the profitability of the industry and to limit the scope of future effort increases (Kennedy, pers. comm.). The fishery moved from effort to catch quota management for the 1998/99 fishing season, with the TACC being set at 1502.5 t for that season (Anon., 1997b). There are currently 314 boats in Tasmania fishing 10 505 traps (Table 1.2) for a catch of approximately 1500 t (Table 1.3). Many fishermen have access to other fisheries as well as rock lobsters (e.g. scallops, shark) but derive most of their income from rock lobster. Recreational fishing for rock lobster is a popular pastime for a small sector of the population. In June 1996 there were 6153 recreational licences issued to fishers allowing them to take rock lobsters with pots and 3465 by diving (Anon., 1997c). The recreational catch for the 1997/98 season was estimated to be 58 t (Lyle & Smith, 1998). In Victoria the fishery is divided into two zones at 143 400 E (Fig. 1.6), an eastern zone with 69 boats and 2615 traps and a western zone with 90 boats and 5388 traps (Table 1.2). About 80% of the total catch of 400±500 t (Table 1.3) comes from the western zone, where the densities of lobsters are higher. Western zone fishers have larger more powerful boats and an average trap licence of 60, whereas the eastern zone fishers have an average trap licence of 38 and are more heavily involved in other

Fig. 1.6

The fisheries for the southern rock lobster Jasus edwardsii in southern Australia.

58

Spiny Lobsters: Fisheries and Culture

Table 1.3 Catch (t whole weight) and fishing effort (thousands of trap lifts) for the Jasus edwardsii fishery in Western Australia, South Australia, Tasmania and Victoria Western Australia

South Australiaa

Tasmaniab

Victoriac

Year

Catch (t)

Catch (t)

Catch (t)

Thousand trap lifts

Catch (t)

Thousand trap lifts

1964/65 1965/66 1966/67 1967/68 1968/69

0.08 0.07 N/A N/A N/A

1513 1787 1946 1752 1700

1969/70 1970/71 1971/72 1972/73

1 3 5 10

1390 1607 1496 1583

1533 1609 1464

1148 1194 1081

1973/74 1974/75 1975/76 1976/77

17 21 20 11

18 23 14

1514 2031 2248 1891

2228 2364 2298

1195 1610 1394 1473

858 1053 1023 1119

N/A N/A N/A

N/A N/A N/A

1977/78 1978/79 1979/80 1980/81

18 17 23 12

24 22 22 11

1857 1938 1908 2810

2204 2337 1991 2523

1432 1569 1613 1854

1089 1067 1066 1136

N/A N/A 564 680

N/A N/A 738 853

1981/82 1982/83 1983/84 1984/85 1985/86

18 21 18 21 18

20 32 33 31 35

2720 2572 2412 2217 2204

2668 2766 2828 2605 2600

1747 2104 1982 2289 1970

1199 1427 1304 1585 1568

628 603 557 520 439

816 803 771 751 725

1986/87 1987/88 1988/89 1989/90

22 20 19 25

33 27 33 33

2207 2468 2275 2525

2519 2782 2554 2489

1862 1816 1896 1828

1617 1686 1693 1786

432 420 369 416

728 688 713 803

1990/91 1991/92 1992/93 1993/94

35 65 73 98

45 101 90 144

2666 3162 2818 2598

2640 2858 2507 2364

1738 1902 1797 1496

1848 2021 2055 1791

389 473 481 528

814 882 995 1003

1994/95 1995/96 1996/97 1997/98 1998/99d

96 100 81 82 76

198 201 159 151 148

2613 2587 2543 2623 2729

2217 2317 2475 2483 2258

1445 1841 1757 1588

1799 1908 1884 1798

508 482 464 501

1030 976 996 962

Thousand trap lifts

Thousand trap lifts

Source: aPrescott (pers. comm.), bKennedy & Gardner (pers. comm.), cMolloy, Hobday & Flint (pers. comm.), dProvisional estimates only.

The Status of Australia's Rock Lobster Fisheries

59

fisheries besides rock lobster, e.g. shark (D. Molloy, Fisheries Department, Victoria, pers. comm.). Recreational lobster fishing is permitted in Victoria using hoop nets or by diving. Fishers are required to hold an amateur fishing licence, which enables them to catch a range of species, including up to four lobsters per person per day. The only survey of recreational fishers to date in Victoria (Hobday et al., 1998) suggested an annual catch of 18 t made by divers who completed a survey which targeted dive shops. This figure did not include catches made by hookah and snorkel divers, or by hoop net fishers, and would therefore have substantially underestimated the recreational lobster catch for the state (Hobday et al., 1998). The fishery for J. edwardsii in Western Australia is on the western extremity of the species distribution and has always been small (100 t or less; Table 1.3). The fishery is centred at Esperance (Fig. 1.6) and dates back to 1965 when fishermen supplied the local market and the larger towns of the inland goldfields. In the early years of the fishery (prior to 1986) most fishers treated the rock lobster fishery as a small adjunct to their main fishing operations (e.g. shark and tuna). In 1984 the tuna fishery, in which most fishers participated, came under quota management and nearly all the fishermen sold their allocations to the large operators in South Australia. Fishers then had more time and capacity to fish and generated additional fishing pressure on the J. edwardsii stocks on the traditional inshore grounds around Esperance, causing catch rates in this area to decline. Fishers began to move further afield, mainly eastwards and into deeper water. In 1987, the fishery became limited entry, with fishermen gaining access and a trap quota based on their catch and fishing effort in the preceding 3 years. Towards the end of the 1980s, deep-water grounds were found which improved the declining catch rates. In the early 1990s the Esperance zone of the fishery expanded westwards to Albany and Augusta and eastwards into the Great Australian Bight, resulting in a large increase in the total catch (Table 1.3). These areas produced good catch rates for a short period, but were rapidly depleted and although still being fished, are of diminishing importance. The Esperance zone is managed separately to the two outer zones and is restricted to 11 licensees with a combined pot holding of 568 pots. This zone of the fishery continues to be fished more intensively now than at any stage prior to the 1990s and appears to be withstanding the increased fishing pressure. The outer zones, by comparison, have 31 licence holders with a combined pot holding of 3860 pots. It is widely acknowledged that there is too much effort in these outer zones and that spiny lobster catch rates in these areas will remain depressed until effort levels are drastically reduced.

1.4.3

Major management controls

Boat and trap restrictions All states in Australia control their J. edwardsii fisheries through limited entry. This sets strict limits on the number of boats and the traps that can be used. Table 1.2

60

Spiny Lobsters: Fisheries and Culture

shows the number of boats and traps licensed to fish J. edwardsii in each state. In all states, the licence (endorsement to fish J. edwardsii) can be transferred from one fisher to another. No additional boats or traps are allowed. Maximum, and in some cases minimum, trap entitlements have also been set (Table 1.2) and most states (Western Australia, South Australia and Tasmania) have defined the size and design of traps, including the incorporation of escape gaps or large mesh to reduce the handling and hence the mortality of undersized animals. Seasonal closures Table 1.4 lists the various seasonal closures for male and female J. edwardsii. Tasmania (Kennedy, 1989) and Victoria (Hobday & Ryan, 1997) have longer closed seasons for females to give them added protection. Minimum size Various minimum sizes (carapace length) have been set for males and females in the five states, owing to differences in the size at first maturity and non-biological historic decisions, which in some cases were based on a size that the market would accept. No states have maximum sizes. Table 1.5 shows the minimum legal size for J. edwardsii in each state. In Tasmania the minimum size for females of 105 mm carapace protects virtually all breeding females on the south coast but is well under the size at 50% maturity for females in the north of the fishery at King and Flinders Islands. Recreational fishing Recreational fishing for J. edwardsii occurs in all states. Table 1.6 lists the main regulations governing the recreational fisheries. Recreational fishing is usually confined to shallow, sheltered waters. Table 1.4 Seasonal closure for the Jasus edwardsii fishery (males and females) in Western Australia (WA), South Australia (SA), Tasmania, Victoria and New South Wales (NSW) Locationa

Males

Females

WA

1 July to 14 November

1 July to 14 November

SA (S zone) SA (N zone) Tasmania

1 May to 30 September 1 June to 31 October 15 September to second Saturday in November, plus the last 5 days in February (commercial only) 1 September to 15 November None

1 May to 30 September 1 June to 31 October 1 May to second Saturday in November, plus the last 5 days in February (commercial only) 1 June to 15 November None

Victoria NSW a

Sources as for Table 1.2.

The Status of Australia's Rock Lobster Fisheries

61

Table 1.5 Legal minimum carapace length (mm) for male and female Jasus edwardsii in Western Australia (WA), South Australia (SA), Tasmania, Victoria and New South Wales (NSW) Locationa

Males

Females

WA SA (S zone) SA (N zone) Tasmania

98.5 98.5 102 110

98.5 98.5 102 105

Victoria NSW

110 110

105 105

a

Sources as for Table 1.2.

1.4.4

Current status of the J. edwarsdii stocks

Throughout its range, J. edwardsii is considered to be fully exploited. There is currently no evidence that the breeding stock has been reduced to a level that is affecting recruitment to the fishery; however, levels of egg production have declined to low levels in most areas of the fishery. Egg production in Tasmania is considered to be below 10% of pristine in the northern areas, but above 80% in some parts of the southern ground (Punt & Kennedy, 1997). In Victoria egg production is considered to lie between 6 and 19% and in South Australia between 10 and 20% of Table 1.6 Rules governing the recreational fishery for Jasus edwardsii in Western Australia (WA), South Australia (SA), Tasmania, Victoria and New South Wales (NSW) Regulation

WA

SAa

Tasmaniab

Victoriac

NSWd

Possession limit Fishing gear

16 per boat

8 per boat

10

No limit

2

2 traps

1 trap, 4 ring nets

No traps, 2 ring nets

8

2 traps or 3 ring/hoop/drop nets 4

5

4

2

Snorkel

Snorkel

Snorkel

Snorkel

Snorkel

Equipment

SCUBA Hookah Hand only

SCUBA Hookah Hand only

SCUBA Hookah Hand only

Hand only

Bag limit

8

SCUBA Hookah No pointed objects 4

5

4

2

Types and no. per person Bag limit Diving methods Air supply

Source: aPrescott (pers. comm.), bKennedy, Gardner & Ford (pers. comm.), cMolloy, Hobday & Flint (pers. comm.), dMontgomery (pers. comm.).

62

Spiny Lobsters: Fisheries and Culture

the historic unfished situations (Hobday et al., 1998; Prescott, pers comm.). Longterm trends in egg production are being monitored by researchers in South Australia, Tasmania and Victoria to ensure that the already depleted state of the brood stock is not further eroded. 1.4.5

Current research

Routine commercial catch and length±frequency monitoring data, together with large-scale southern lobster tag release and recapture projects, have provided the basis for considerable stock-assessment modelling work undertaken in South Australia (McGarvey et al., 1997), Victoria (Treble, 1996; Hobday et al., 1998) and Tasmania (Frusher et al., 1997; Punt & Kennedy, 1997; Punt et al., 1997). Much of this work has focused on the calculation of exploitation rates in the lobster fisheries of the southern states, as this is crucial to future management strategies. In addition, work has been undertaken in all southern states to establish the state of egg production and in two of the states (South Australia and Tasmania) on the estimation of size transition matrices for the lobster populations. A large-scale programme to monitor the level of puerulus settlement across the southern states of South Australia, Victoria and Tasmania is being undertaken to obtain an understanding of the spatial and temporal distribution of pueruli. Later, this may provide a mechanism for predicting the commercial catch in advance of the event and an indication of factors contributing to annual variation. The longer-term trends in the index of puerulus abundance may also provide the first indication of any stock recruitment problems, i.e. a reduction in the size of the breeding stock to the point where it results in a reduction in the level of puerulus settlement. Data to date show marked seasonal and interannual patterns in settlement for different regions (Frusher et al., 1997). 1.4.6

Conclusions

Jasus edwardsii is fully exploited throughout its range and in most areas the breeding stock is considered to be well below 20% of the levels in the fishery prior to exploitation. There are no indications to date that recruitment is being affected by the size of the brood stock. Most of the fishery (southern South Australia, Tasmania) is now under a TACC form of management and consideration is being given to implementing this form of management in Victoria (Hobday, pers. comm.).

1.5

The western rock lobster (Panulirus cygnus) fishery

The western rock lobster (P. cygnus) now supports the largest rock lobster fishery in the world, with seasonal catches averaging 10 800 t over the past 19 years (1980/81

The Status of Australia's Rock Lobster Fisheries

63

to 1998/99) and the 1998/99 season producing a record 13 t. The 596 vessels licensed to participate in the fishery share between $200 and $300 million gross per season, making it Australia's most valuable single species fishery. Because of the high prices paid for P. cygnus and the good returns that a fisher can expect, the stock has experienced very high and increasing exploitation during the 1980s and 1990s. The stock now is fully exploited.

1.5.1

Distribution and life history

Panulirus cygnus is found in commercial quantities from just east of Cape Leeuwin (34 240 S) in the south to Shark Bay (24 450 S) in the north (Fig. 1.7). The juveniles populate the shallow (<1 m) inshore limestone reefs and the breeding stock is found offshore (35±90 m) and at the Abrolhos Islands situated on the continental shelf edge. Mating occurs between July and December or January, when the male deposits a sperm packet (tar spot) on the sternal plate of the female. The females attach the fertilized eggs to hairs on appendages on the underside of their abdomen (tail), where they are incubated for 3±9 weeks, depending on the water temperature. The higher the temperature, the faster development occurs. Eggs hatch from late October through to February or March, releasing first-stage phyllosoma larvae. Phyllosomes rise to the surface at night and are transported offshore by wind-driven currents, some, for at least 1500 km (Phillips, 1981). The highest concentrations of larvae are found between latitudes 27 S and 31 S and 400±1000 km offshore due west of the approximate centre of the adult distribution on the coast (Chittleborough & Thomas, 1969; Phillips et al., 1979). As the larvae develop (over 9±11 months) their diurnal vertical movements take them deeper in the water column where, during midto-late larval life, gradually they are transported back towards the continental shelf by eastward-flowing currents (Phillips, 1981). The Leeuwin Current that flows southwards along the edge of the continental shelf may also play a role in the eastward transport of the late stage phyllosomes by trapping larvae in gyres that move them towards the coast (Pearce & Phillips, 1988; Phillips et al., 1991). When the late-stage phyllosomes are close to the edge of the continental shelf they metamorphose into the puerulus stage, which swims and is transported across the shelf to the shallow inshore limestone reefs (<40 m), where they settle and commence the juvenile phase (Phillips, 1981). Storm conditions that move the surface waters shoreward are prevalent during the period of puerulus settlement in late winter and spring (southern hemisphere) and may provide a mechanism for rapidly transporting pueruli across the continental shelf to their benthic juvenile habitat (Caputi & Brown, 1989, 1993). After settlement, it takes 3±4 years for the juveniles to reach the minimum legal size of 76 mm CL, at which time they are moulting two or three times per year, with moult increments of 3±7 mm (Melville-Smith et al., 1997). It is at about this age and

64

Spiny Lobsters: Fisheries and Culture

Fig. 1.7 The Western Australian coast showing the migration of the western rock lobster Panulirus cygnus.

The Status of Australia's Rock Lobster Fisheries

65

size that many of these premature animals undergo a synchronized moult in early November and move offshore in a pre-breeding migration. The majority of these pale-shelled animals, known locally as `whites', migrate into deeper water (>40 m), directly west and north-west of their juvenile reefs (Fig. 1.7), to where the bulk of the breeding stock is situated (Morgan, 1977; Phillips, 1983; Chubb et al., unpubl.). Some of the migrating lobsters continue past the deep-water breeding habitat to the edge of the continental shelf, combine with lobsters moving from deeper water areas where they probably settled as pueruli and then move northwards, broadly following the 140±180 m depth contour (Fig. 1.7). As the migrating lobsters migrate north, some move back inshore to suitable habitat in depths of 40±100 m. Abrolhos Islands `white' lobsters are joined by some coastal `whites' on the `Big Bank run', where lobsters migrate northwards out of the Abrolhos zone (Fig. 1.7) (Anon., 1989). It is not known how far north the animals migrate, but large quantities of legal-size lobsters are taken during the migration and the mainly sublegal-size remnants may be in poor physical condition, in some seasons, by the time they are west of Shark Bay (Fig. 1.7) (Chubb et al., 1994; Chubb et al., unpubl.). One to 2 years after reaching legal size (i.e. about 6±7 years after hatching), the female lobsters of the coastal populations commence breeding at a CL of 90±100 mm (50% mature) (Chittleborough, 1976; Chubb, 1991). They are estimated to produce about 50% of total egg production (Chubb, 1991). At the Abrolhos Islands, females commence breeding well below the legal minimum size, with 50% being mature at 65 mm CL (Chubb, 1991). The reason for the smaller size at sexual maturity at the Abrolhos Islands is unknown, but it may be influenced by the very high densities of lobsters in this region and the fact that the Abrolhos is a very different habitat area from the coast, comprising coral atolls and reefs. The islands also are directly in the path of the warm tropical southward-flowing Leeuwin Current, which maintains significantly higher seawater temperatures than those experienced on the coast.

1.5.2

History of the fishery

Aboriginal people were the first to use P. cygnus as a food source, to support their hunter±gatherer existence. A small commercial fishery developed soon after European settlement and in 1897 the first regulation for the fishery was proclaimed, namely a minimum legal size (weight), which has remained virtually unchanged to the present day. By the 1930s, a small fleet of boats was operating out of Fremantle and Geraldton (Fig. 1.7) supplying some 250 t annually to the local market. It was not until the end of World War II (1945), when the export of frozen lobster tails to the USA commenced, that exploitation began in earnest. The export of 1000 t in 1948 grew to 8000 t by 1958. Since then, the 10 seasons 1970/71 to 1979/80 produced average catches of 9250 t with an average of 10 800 t over the next 19 seasons (1980/ 81 to 1998/99). A record catch of 13 000 t was taken in 1998/99 with catches in

66

Spiny Lobsters: Fisheries and Culture

excess of 12 000 t on four occasions between 1987/88 and 1992/93 (see Caputi et al., chapter 18, for a table of catch and fishing effort). During the developmental years of the fishery (1945±1962) there were no restrictions on licences and gear and the number of new entrants, boats and pots (traps) grew rapidly. By the late 1950s and early 1960s, the fishing effort was still rising rapidly but the catch had stabilized at 7±8 000 t. Fishers saw their catch rates and individual catches declining and feared for their economic viability. In 1963, after representation from the fishing industry, the government introduced a policy of `limited entry' and closed the fishery to new entrants. In 1965 the number of pots that fishers could use also was strictly controlled, limiting the total number of pots to 76 623 and boats to 845. Since the introduction of limited entry, both nominal fishing effort (pot lifts) and the effectiveness of that effort continued to increase as fishers built larger vessels and worked more days per month, gaining experience and improving their gear and fish-finding technology. In an attempt to offset these increases in fishing effort and efficiency, management, in consultation with industry, introduced measures to shorten the fishing season, strictly define pot design and dimensions and reduce the number of pots and boats in the fishery (Brown, 1991; see Caputi et al., Chapter 18, for further details). These measures have been successful in slowing the rate of increase in effective fishing effort, but not stopping it. An active recreational fishery, operating in the inshore waters (<30 m) around population centres, developed alongside the commercial fishery. In 1988/89, a total of 16 100 licensed recreational fishers caught 290 t, equivalent to 2.3% of the commercial catch of 12 300 t. Seventy per cent of recreational fishers used pots (maximum of two per person), 22% went diving and 7% used both methods of capture (Melville-Smith & Anderton, 2000). From continuing postal surveys it is estimated that the annual recreational catch was between 2 and 3% of the commercial catch. By 1998/99 the number of licences had risen to 32 800, with recreational fishers catching an estimated 630 t, or the equivalent of 4.8% of the commercial catch of 13 000 t. The proportion of recreational fishers using both potting and diving to catch lobsters was slightly higher at 11%, but the proportion using pots had declined to 54% while the proportion diving increased to 34% (Melville-Smith & Anderton, 2000).

1.5.3

Major management controls

Commercial fishing Caputi et al. (Chapter 18) provides a chronological listing and some explanation of the regulations that have been used to manage the P. cygnus fishery since 1897 (see also Hancock, 1981; Brown, 1991). The main thrust of the management measures used in this input-controlled fishery up to the early 1990s has been to contain the inevitable increases in effective fishing effort that have occurred as the fishery and

The Status of Australia's Rock Lobster Fisheries

67

technology developed, and curtail the wasteful mortality of juveniles caused by poor fishing practices (Brown & Caputi, 1986). The regulations forming the foundation of management for the fishery are: 1.

2. 3. 4. 5.

6. 7.

a minimum legal CL of 76 mm (proclaimed as an equivalent whole weight in 1897). This provides protection for breeding females only at the Abrolhos Islands (see section on Distribution and life history) a ban on the taking of egg-bearing females (proclaimed 1899) a closed season from 16 August to 14 November (proclaimed 1962) and an extended closure from 1 July to 14 November (proclaimed 1978) limited entry, which restricted the number of boats and traps that could be used in the fishery (proclaimed 1963 and 1965) the incorporation of a single escape gap (1966); increased to three escape gaps into every trap and strict design and dimension rules for traps (proclaimed 1984 and 1986) a temporary reduction in the number of pots (10%) for the 1986/87 season (proclaimed 1986) a permanent 10% reduction in pots at 2% per season over the five seasons 1987/ 88±1991/92 (proclaimed 1987).

The period 1992±1998 Management in the 1990s centred solely on rebuilding the breeding stock by significant reductions in the rate of exploitation. The reasons for so doing were numerous. Declines in the standard indices of egg production to levels never before recorded were seen and an estimate from the fishery model (Walters et al., 1993) suggested that egg production had declined to 15±20% of its unfished level. In addition, the deep-water breeding stock became increasingly vulnerable to capture because of the use of Global Positioning Systems (GPS ± satellite navigation) and colour echo sounders (Brown et al., 1995). This equipment enabled fishers to map the lobster habitat accurately and to return consistently to the same locations, something previously not possible even with radar. Now the next level of sophistication, the extremely accurate differential GPS, is in use. Coupled with the above were the forecast of a number of poor recruitment years due to the very low puerulus settlements seen over 1990±1994 and the prospects of small numbers of legal-sized rock lobsters surviving to reach sexual maturity in a population that relied on one or two cohorts for the bulk of the egg production. Perhaps the most convincing argument was the identification of the first signs of recruitment overfishing (Caputi et al., 1995) resulting from the very heavy exploitation of the rock lobster stock. In July 1992 a package of management initiatives, for the 1992/93 season, was introduced into the fishery following extensive industry consultation of a wide range of options.

68

Spiny Lobsters: Fisheries and Culture

For the entire fishery l

l

a maximum legal size for females of 115 mm CL to boost the numbers of larger older breeding females and reduce the reliance on one or two age classes for egg production a prohibition on the retention of female lobsters (mature) that were mated (tarspotted) and/or possessing ovigerous setae on their pleopods from 15 November to 28 February inclusive, to improve the overall survival of breeding female rock lobsters.

Above the 30 S latitude (Zone A and B: see Fig. 1.1 and text in Caputi et al., Chapter 18): l

l

a temporary 10% pot reduction from the opening of the season, 15 November, to 9 January inclusive, to reduce the fishing mortality of `whites' on their prebreeding migration a closure (no fishing) from 10 January to 9 February inclusive.

Below the 30 S latitude (Zone C: see Fig. 1.1 and text in Caputi et al., Chapter 18): l

boats to nominate a port from which they must operate (land their catch at) for the entire season (15 November to 30 June). This measure was designed to restrict the movement of the Zone C fleet, thereby reducing its efficiency and hence the overall exploitation rate on the stock. It also has catch-sharing ramifications as some fishermen move around the fishery, in pursuit of higher catch rates, far more than others do.

The results of this package were assessed by researchers and presented to the Rock Lobster Industry Advisory Committee (RLIAC). The RLIAC is a ministerial advisory group that comprises expertise from the commercial fishery, the recreational fishery, the processing sector and Fisheries Western Australia. It considers matters relating to the commercial rock lobster fishery in an objective corporate manner and recommends to the Minister for Fisheries options for management. The RLIAC considered the research and industry advice and found that maximum legal size for females, the protection of mature females (setose and tar-spotted) and the temporary pot reductions were all useful management tools in the context of rebuilding the breeding stock. The summer closure in the north and the `home porting' rule, as it became known, were ineffective. A new management package was implemented in 1993/94, which was instrumental in rebuilding the breeding stock (and egg production) to levels considered safe for this fishery (RLIAC, 1993a, b; Anon., 1998c). With subtle changes, the package has remained in place to the time of writing (1999/2000 season). The regulations were: l l

a temporary 18% pot reduction for the whole season to reduce the overall exploitation rate on the stock an increase in the legal minimum size from 76 to 77 mm CL for the period of the `whites' fishery (November 15±January 31, inclusive) to promote both the

The Status of Australia's Rock Lobster Fisheries

l l

69

survival of migrating lobsters and their dispersal to the breeding grounds where they become less vulnerable to fishing a total prohibition on the landing of setose and tar-spotted lobsters for the whole season to promote the survival of the existing breeding stock the retention of a legal maximum size for females of 115 mm CL in the southern sector of the fishery and 105 mm CL in the central and northern sectors. This variation was required to balance the variable impact on catches of the new minimum size rule due to changes in the size structure of lobster populations from south to north and the target levels of breeding stock to be reached in each management area.

Recreational fishing Recreational fishers must comply with the same rules as commercial fishers; however, they are restricted to a limit of two pots per licensed person with a maximum of four pots per boat, an individual daily bag limit of eight rock lobsters and a boat limit of 16. Recreational fishers (but not commercial fishers) may also dive and use their hands or a blunt crook or hand-held snare to assist in catching their bag limit.

1.5.4

Current status of the stock

Natural mortality, fishing mortality and total mortality for P. cygnus have been estimated at 0.23, 0.64±0.78 and 0.87±1.01, respectively (Phillips & Brown, 1989). The exploitation rate is estimated in excess of 85% through the animal's entire life and about 60±70% annually (Phillips & Brown, 1989). These estimates are based on a measure of fishing effort that does not take account of the increases in fishing efficiency (power) that have occurred through improvements in boats, gear and fishfinding technology (e.g. colour echo sounders and GPS). Therefore, they probably underestimate the real situation (Caputi et al., Chapter 18). Prior to the introduction of the 1992/93 and 1993/94 management arrangements, breeding stock levels were very low. One probable reason that the fishery may have avoided significant recruitment failure was the substantial numbers of sublegal-sized breeding female rock lobsters in the Abrolhos Islands area. It was estimated that this undersized part of the breeding stock was producing about 35% of the whole fishery's egg production and was acting as a buffer against the effects of fishing. An absence of these rock lobsters probably would have meant the economic demise of the fishery, given the previous levels of exploitation. As a result of the 1993/94 management package, the breeding stock and egg production have been returned to at least the levels recorded in the late 1970s to early 1980s and appear to be stabilizing (Anon., 1998c). Environmental conditions play a vital role in the seasonal recruitment of pueruli to the nursery reefs and subsequently

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to the catch. For example, although the spawning stock was greatly reduced in the early 1990s, good environmental conditions allowed levels of puerulus settlement equal to those seen in past years (see Phillips et al., Chapter 17). However, even with high levels of egg production, the puerulus settlement in 1998/99 was one of the lowest on record (Chubb, unpubl.). Environmental factors then are the dominant feature determining the level of recruitment to the fishery (Caputi & Brown, 1989, 1993; Pearce & Phillips, 1994). The fishery is fully exploited and catches are very dependent on the new recruit class entering the fishery. Thus, catches can vary by up to 50% (from 8000 to 13 000 t), because of variations in puerulus settlement due to changing environmental conditions. The sustainability of the western rock lobster fishery is now assured with the objective of maintaining the exploitation rate at a level that will preserve the breeding stock at current densities. 1.5.5

Current research

Databases The five main databases are: l l l l l

commercial fishers' compulsory monthly catch and fishing effort returns commercial fishers' voluntary research logbook daily catch and fishing effort data at-sea commercial catch monitoring data processors' compulsory production and returns by grade (size) category the annual index of puerulus settlement.

These databases are maintained, updated and improved continually, and form the basis for stock assessment (see Caputi et al., Chapter 18, for further details). Spawning stock estimates Indices of the abundance of the spawning stock of the western rock lobster are crucial in maintaining the sustainability of the fishery. Indices have been calculated from commercial monitoring data and research logbook data in combination with biological information collected by Chubb (1991; Chapter 14). One of the conclusions of Chubb's (1991) study was that estimates of breeding stock based on catch-rate data from the commercial fishery were heavily biased, owing to underestimates of effective effort. Thus, indices based on commercial data have been corrected for the estimated increases in effective effort presented by Brown et al. (1995). To avoid the bias inherent within fishing industry catch-rate-based estimates it was decided to commence a breeding-stock survey in 1992 that was independent of the fishery. The survey requires chartered rock lobster boats to fish standard pots across a set grid pattern across known breeding grounds (and recorded on GPS) for a set period over the new moon phase at a similar time each year (the moon phase

The Status of Australia's Rock Lobster Fisheries

71

dictates the actual dates). The catch rates obtained provide relative indices of abundance after being standardized for year-to-year variations in catchability resulting from differing environmental influences (e.g. temperature and swell conditions, etc). The cost-effectiveness of a smaller programme (three survey locations instead of six) is being examined currently. Catch forecasts Catch predictions for the total fishery have been made since 1981 using puerulus settlement data (Hancock, 1981; Morgan et al., 1982; Caputi et al., 1995; Phillips, 1986; Phillips et al., Chapter 19). An index of abundance of pre-recruits 1 year prior to entering the fishery (Caputi & Brown, 1986; Caputi et al., 1995; Phillips et al., chapter 19) was obtained from the commercial monitoring data. This index became less reliable since most sublegal-sized lobsters were escaping capture following the introduction of the multiple escape gap regulation. Nowadays, the puerulus settlement data are used to give a 3±4 year forward estimate not only of total catch, but also of `whites' catches in the coastal management zones and `reds' catches in all zones (Caputi et al., 1995). Caputi et al. (1995) also examined the effect of nominal fishing effort levels on the catch forecasts. This investigation is continuing as longer time series of puerulus settlement data become available from six additional puerulus collection sites established in 1985. The usefulness of combinations of settlements from different locations to predict regional catches is being assessed. The forecasts are widely accepted by industry as accurate and are used in a general way for business planning and investment decisions. Movement, migration and growth Large- and small-scale tagging programmes were undertaken through the 1980s and 1990s to determine the extent and strength of the pre-breeding migration and to obtain estimates of growth for various sectors of the fishery. This information has been analysed and a description of migration by the western rock lobster provided (Chubb et al., in prep.). Growth data have been analysed to form the growth transition matrix (Cao et al., in prep.) in the value-optimization model and Hall and Chubb (pers. comm.) have examined other aspects of growth to include in the model assessing the effects of the individual components of the current management package. Effective fishing effort and fishing power estimates An ongoing core programme is to determine the rate at which fishing power has increased over the last 20 years owing to changes in boats, gear and fish-finding technology. The introduction to the fleet of GPS and other technologies, and changes in vessel size and power are monitored and components of fishing power and efficiency are being examined (e.g. Fernandez et al., 1997).

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Estimates of fishing efficiency increases will be used to adjust fishing effort data (pot lifts) to remove the bias from industry-based catch-rate data, which provide the basis for population abundance estimates and stock assessment (see Caputi et al., Chapter 18). Recreational fishing The first survey of recreational fishing conducted from 1976 to 1978 estimated the recreational catch at 174 t (1.6% of the commercial catch) (Norton, 1981). A followup large survey of the recreational fishery was conducted in 1988/89, using field and postal survey techniques. The results showed the recreational catch was 3±4% of the commercial catch from the fishery but, for the first time, highlighted that in the 0± 20 m depth range around the major population centres of Perth and Geraldton, intense competition for the rock lobster resource existed. In these areas, the recreational catch was estimated at 26% and 21%, respectively, of the total catch (recreational plus commercial) (Chubb et al., unpubl.). Annual mail surveys have been conducted since 1986/87 and form the basis of the assessment of recreational catch and fishing effort each season. In 1998/99 recreational landings totalled 626 t or 4.8% of the commercial catch (Melville-Smith & Anderton, 2000). The recreational data are taken into account in stock assessments. Modelling In the early 1990s, a fishery model was developed which enabled the assessment of a wide range of management options (Walters et al., 1993). Currently, a value optimization model is being developed to assess the biological and economic impacts of future management options on a regional basis. In addition, a model assessing the impacts of the components of the current management package has been developed (see Hall & Brown, Chapter 21). Both models use different but highly sophisticated approaches in which their sensitivity to the assumptions in the models is tested. These models, the culmination of our understanding of the biology and fishery for the western rock lobster, are already showing the limits to which the data can be used and will direct research towards improving data-collection procedures and providing hard data in place of sensitive assumptions.

1.5.6

Management proposals

While an assessment of the combined effects of the five seasons of stable management from 1993/94 to 1997/98 has been undertaken (Anon., 1998), a model has been developed to tease out the effects of the individual components of those management arrangements. This is an important step, since questions are being asked by industry as to whether an individual component such as the full protection of all breeding

The Status of Australia's Rock Lobster Fisheries

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females (setose, tar-spotted and egg-bearing) all season, by itself would maintain the breeding stock at the required level. All components of the current package would interact with the others to produce an impact on the stock. To ascertain the individual component impacts on the stock required a sophisticated modelling approach (see Hall & Brown, Chapter 21). With the fishery sustainability of the fishery now assured, both industry and management need to focus on achieving the maximum economic rent (profit) from the western rock lobster fishery and maximizing the benefits to Western Australia from the exploitation of this community-owned resource. To assist in the assessment of future management options, a value-optimization modelling approach is being developed. A biological model has been developed to assess the stock responses; these are then linked to a set of economic data, which will effectively cost out the proposed options, or combination of options, and provide an ability to rank options in terms of their economic benefit and their impact on the brood stock. Proposed arrangements that help to reduce fishing costs and at the same time achieve the management objectives, in general, would increase profits from the fishery. At the same time, the general philosophy of management is being debated; that is the issue of input controls versus output controls (quota). Total allowable catches (TAC) and individual transferable quotas (ITQ) are often touted as being the best option to maximize the economic benefits of a fishery. From a strictly theoretical, `rational economic' viewpoint this is true. However, in terms of value to the community at large, the judgement of which philosophy to embrace becomes a balancing exercise. The introduction of quotas, in time, would lead to adverse impacts on the economic and social fabric of the industry, especially in small coastal communities, and significantly increase research and enforcement costs (all fully cost-recovered from the fishery), all of which could defray the theoretical cost benefit of quota management. While it is true that many rock lobster fishers abhor restrictions of any nature, industry still favours input controls at this time. The RLIAC recently has introduced a proposal to package management advice to the Minister for Fisheries as a series of rolling 3-year plans. This involves assessing the management requirements for a 3-year period followed by periods where each year the first year is dropped from consideration and the fourth added, and so on. The current view is to continue the existing management arrangements (see Section 1.5.3) to maintain sustainability. Maximizing the benefits of other management options to the community of Western Australia will be assessed as the value optimization modelling proceeds.

1.5.7

Conclusions

The western rock lobster (P. cygnus) is fully exploited throughout its range and supports a substantial shallow-water recreational fishery. Modern, purpose-built commercial fishing vessels and sophisticated electronic fish-finding and navigation

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equipment have dramatically increased the effectiveness of commercial fishing effort (nominally measured as pot lifts) over the past 20 years (Brown et al., 1995, Caputi et al., Chapter 18). In particular, fishers now are able to target very precisely the dispersed deep-water fishing grounds that the breeding stock inhabits. Recognition of the fact that total egg production was dangerously low in the early 1990s and that recruitment overfishing was a real possibility led to the introduction of management arrangements that rebuilt the breeding stock within 5 years. This was achieved with a balanced combination of measures designed to reduce the overall exploitation rate and promote the survival of breeding females and recruits to the breeding stock. Effective fishing effort slowly continues to increase; however, the sustainability of the resource is currently assured. Management, along with maintaining the sustainability of the western rock lobster fishery, now has the task of maximizing the benefits from this community-owned resource to the industry and the people of Western Australia through the industry-preferred philosophy of input controls.

References Andrew, N.L., Reid, D.D. & Murphy, J.J. (1997) Estimates of the 1997 recreational abalone harvest in N.S.W. N.S.W. Fisheries Internal Report, 13 pp. Anon. (1989) Tagging trails for deepwater rock lobsters. Western Fisheries Magazine, July/August 1989, 18±20. Anon. (1992a) Torres Strait lobster. Fishery Status Report, February 1992. Prepared by Department of Primary Industry and Energy ± Bureau of Rural Resources, Canberra, Australia. Anon. (1992b) Report of the Rock Lobster Steering Committee, NSW Fisheries. Chairman B.K. Bowen, 7 July 1992, 33 pp. Anon. (1997a) Marine Recreational Fishing in New South Wales: A Brief Guide to Rules. New South Wales Fisheries, New South Wales, Australia. Anon. (1997b) Rock Lobster Fishery Policy Document December 1997. Department of Primary Industry and Fisheries, Tasmania, 83 pp. Anon. (1997c) Draft Fisheries Management Plan and Policy Document for the Rock Lobster Fishery for Public Consultation: June 1997. Department of Primary Industry and Fisheries, Tasmania, 63 pp. Anon. (1998a) Torres Strait Lobster fishery. Fishery Status Report, Bureau of Rural Sciences, Canberra, Australia, 175 pp. Anon. (1998b) NSW Fisheries Status of Fisheries Resources 1997/98. NSW Fisheries Research Institute, New South Wales, Australia, 214 pp. Anon. (1998c) The effects of five years (1993/94 to 1997/98) of stable management in the western rock lobster fishery. Commercial Fisheries Management Bulletin, Fisheries WA, 8 pp. Booth, J.D. (1994) Jasus edwardsii larval recruitment off the east coast of New Zealand. Crustaceana, 66, 295±317. Booth, J.D., Street, R.J. & Smith, P.J. (1990) Systematic status of the rock lobsters Jasus edwardsii from New Zealand and Jasus novaehollandiae from Australia. N.Z. J. Mar. Freshwat. Res., 24, 239±49. Brown, R.S. (1991) A decade (1980±1990) of research and management of the western rock lobster (Panulirus cygnus) fishery of Western Australia. Rev. Invest. Mar., 12, 204±22. Brown, R.S. & Caputi, N. (1986) Conservation of recruitment of the western rock lobster (Panulirus cygnus) by improving survival and growth of undersize rock lobsters captured and returned by fishermen to the sea. Can. J. Fish. Aquat. Sci., 43, 2236±42.

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Brown, R.S., Caputi, N. & Barker, E.H. (1995) A preliminary assessment of the effect of increases in fishing power on stock assessment and fishing effort of the western rock lobster (Panulirus cygnus George 1962) fishery in Western Australia. Crustaceana, 68, 227±37. Caputi, N. & Brown R.S. (1986) Relationship between indicies of juvenile abundance and recruitment in the western rock lobster (Panulirus cygnus) fishery. Can. J. Fish. Aquat. Sci., 43, 2131±9. Caputi, N. & Brown, R.S. (1989) The effect of environmental factors and spawning stock on the puerulus settlement of the western rock lobster. In Workshop on Rock Lobster Ecology and Management (Ed. by B.F. Phillips), 29 pp. CSIRO Marine Laboratories Ref. 207. Caputi, N. & Brown, R.S. (1993) The effect of the environment on the puerulus settlement of the western rock lobster (Panulirus cygnus) in Western Australia. Fish. Oceanog., 2, 1±10. Caputi, N., Brown, R.S. & Phillips, B.F. (1995) Prediction of catches of the western rock lobster (Panulirus cygnus) based on indices of puerulus and juvenile abundance. ICES Mar. Sci. Symp., 199, 287±93. Channells, P.C. (1986) History and development of the Australian rock lobster fishery for Panulirus ornatus. In Torres Strait Fisheries Seminar, Port Moresby, 11±14 February 1985 (Ed. by A.K. Haines, G.C. Williams and D. Coates), pp. 184±9. Australian Government Printing Service, Canberra, Australia. Chittleborough, R.G. (1976). Breeding of Panulirus longipes cygnus under natural and controlled conditions. Aust. J. Mar. Freshwat. Res., 27, 499±516. Chittleborough, R.G. & Thomas, L.R. (1969). Larval ecology of the Western Australian marine crayfish, with notes upon other panulirid larvae from the eastern Indian Ocean. Aust. J. Mar. Freshwat. Res., 20, 199±223. Chubb, C.F. (1991) Measurement of spawning stock levels for the western rock lobster, Panulirus cygnus. Rev. Invest. Mar., 12, 223±33. Chubb, C.F., Barker, E.H. & Dibden, C.J. (1994) The Big Bank region of the limited entry fishery for the western rock lobster, Panulirus cygnus. W.A. Fish. Res. Rep. No. 101, 1±20. Copes, P. (1978) Resource Management for the Rock Lobster Fisheries of South Australia. Report commissioned by the Steering Committee for the review of the Fisheries for the South Australian Government, 295 pp. CSIRO (1999) Research for Management of the Ornate Tropical Rock Lobster, Panulirus ornatus Fishery in Torres Strait, Progress Report to Torres Strait Protected Zone Joint Authority, 2 pp. Fernandez, J., Cross, J. & Caputi, N. (1997) The impact of technology on fishing power in the western rock lobster (Panulirus cygnus) fishery. In Proceedings of the International Congress on Modelling and Simulation (MODSIM 97), Vol. 4 (Ed. by A.D. MacDonald & M. AcAleer), pp. 1605±10. The Modelling and Simulation Society of Australia Inc., Canberra, Australia. Frusher, S.D., Kennedy, R.B. & Gibson, I.D. (1997) Precision of exploitation-rate estimates in the Tasmanian rock-lobster fishery based on change-in-ratio techniques. Mar. Freshwat. Res., 48, 1069±74. George, R.W. (1968) Tropical spiny lobsters, Panulirus spp. of Western Australia (and the IndoWest Pacific). J.R. Soc. W. Aust., 51, 33±8. George, R.W. (1972) South Pacific Islands ± Rock Lobster Resources, pp. 1±42. A Report prepared for the South Pacific Islands Fisheries Development Agency. FAO, Rome. Hancock, D.A. (1981) Research for management of the rock lobster fishery of Western Australia. Proc. Annu. Gulf Carib. Fish. Inst., 33, 207±29. Hobday, D.K. & Ryan, T.J. (1997) Contrasting sizes at sexual maturity of southern rock lobsters (Jasus edwardsii) in the two Victorian fishing zones: implications for total egg production and management. Mar. Freshwat. Res., 48, 1009±14. Hobday, D.K., Ryan, T.J., Thomson, D.R. & Treble, R.J. (1998) Assessment of the Victorian rock lobster fishery. FRDC Project 92/104 Final Report, 177 pp. Kennedy, R.B. (1989) More closures for rock lobsters. Fishing Today 2, 30±1.

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Kennedy, R.B. (1990) Juvenile crays: where do they settle and when? Fishing Today 3, 22±3. Liggins, G.W., Scandol, J., Montgomery, S., Craig, J. & MacBeth, W. (1999) An assessment of the NSW eastern rock lobster resource for 1999±2000. NSW Fishery Resource Assessment Series, 7, 51pp. Lyle, J.M. & Smith, J.T. (1998) Pilot survey of licensed recreational sea fishing in Tasmania ± 1995/ 96. Department of Primary Industry and Fisheries Tasmania, Marine Research Laboratories, Taroona, Technical Report 51, 55 pp. MacDiarmid, A.B. (1988) Experimental confirmation of external fertilisation in the southern temperate rock lobster Jasus edwardsii (Hutton) (Decapoda: Palinuridae). J. Exp. Mar. Biol. Ecol., 120, 277±85. McGarvey, R., Matthews, J.M. & Prescott, J.H. (1997) Estimating lobster recruitment and exploitation rate from landings by weight and numbers and age-specific weights. Mar. Freshwat. Res., 48, 1001±8. McGarvey, R., Ferguson, G.J. & Prescott, J.H. (1999) Spatial variation in mean growth rates at size of southern rock lobster, Jasus edwardsii, in South Australian waters. Mar. Freshwat. Res., 50, 333±42. Melville-Smith, R. & Anderton, S.M. (2000) Western rock lobster mail surveys of licensed recreational fishers 1986/87±1998/99. Western Australia Fisheries Research Report No. 122. Melville-Smith, R., Jones, J.B. & Brown, R.S. (1997) Biological tags as moult indicators in Panulirus cygnus (George). Mar. Freshwat. Res., 48, 959±65. Montgomery, S. (1991) The rock lobster fishery. In New South Wales Fisheries Department Biennial Report of Fisheries Research 1989±1991. New South Wales Division of Fisheries, Department of Agriculture, pp. 41±2. Montgomery, S.S. (1992) Sizes at first maturity and at onset of breeding in female Jasus verreauxi (Decapoda: Palinuridae) from New South Wales waters, Australia. Aust. J. Mar. Freshwat. Res., 43, 1373±9. Montgomery, S.S. (1995) Patterns in landings and size composition of Jasus verreauxi (H. Milne Edwards, 1851) (Decapoda, Palinuridae), in waters off New South Wales, Australia. Crustaceana, 68, 257±66. Montgomery, S.S. & Kittaka, J. (1994) Occurrence of pueruli of Jasus verreauxi (H. Milne Edwards, 1851) (Decapoda, Palinuridae) in waters off Cronulla, New South Wales, Australia. Crustaceana 67, 65±70. Montgomery, S.S., Chen, Y., Craig, J. & Diver, L. (1998) An assessment of the NSW eastern rock lobster resource for 1998/99. NSW Fishery Resource Assessment Series 4, 65 pp. Montgomery, S.S., Craig, J.R. & Tanner, M. (1996) The abundance of the eastern rock lobster, Jasus verreauxi, along the New South Wales coast. Fisheries Research and Development Corporation Project 92/14 Final Report, November 1996. Montgomery, S.S., Craig, J., Tanner, M. & Chen, T. (1997) An assessment of the NSW rock lobster resource for 1997/98. NSW Fishery Resource Assessment Series 2. Morgan, G.R. (1977) Aspects of the population dynamics of the western rock lobster and their role in management. Ph.D. thesis, University of Western Australia, Nedlands, Western Australia, 341 pp. Morgan, G.R., Phillips, B.F. & Joll, L.M. (1982) Stock and recruitment relationships in Panulirus cygnus the commercial rock (spiny) lobster of Western Australia Fish. Bull., 80, 475±86. Norton, P.N. (1981) The amateur fishery for the western rock lobster. Dept. Fish. Wildl. West. Aust. Report No. 46, 108 pp. Ovenden, J.R., Brasher, D.J. & White, R.W.G. (1991) Mitochondrial DNA analysis of the red rock lobster (Jasus edwardsii) supports an apparent absence of population subdivision throughout Australasia. Mar. Biol., 26, 53±8. Pearce, A.F. & Phillips, B.F. (1988) ENSO events, the Leeuwin Current and larval recruitment of the western rock lobster. J. Cons. Int. Explor. Mer., 45, 13±21.

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Pearce, A.F. & Phillips, B.F. (1994) Oceanic processes, puerulus settlement and recruitment of the western rock lobster Panulirus cygnus. In The Bio-physics of Marine Larval Dispersal. (Ed. by P. Sammarco & M. Heron), pp. 279±303. American Geophysical Union, Washington, DC, USA. Phillips, B.F. (1972) A semi-quantitative collector of the puerulus larve of the western rock lobster Panulirus longipes cygnus George (Decapoda, Palinuridea). Crustaceana, 22, 147±54. Phillips, B.F. (1981) The circulation of the south eastern Indian Ocean and the planktonic life of the western rock lobster. Oceanogr. Mar. Biol., 19, 11±39. Phillips, B.F. (1983) Migrations of pre-adult western rock lobsters, Panulirus cygnus, in Western Australia. Mar. Biol. 76, 311±18. Phillips, B.F. (1986) Predictions of commercial catches of western rock lobsters Panulirus cygnus George. Can. J. Fish. Aquat. Sci., 43, 2126±30. Phillips B.F. & Brown R.S. (1989) The West Australia rock lobster fishery: research for management. In Marine Invertebrate Fisheries: Their Assessment and Management (Ed. by J.F. Caddy), pp. 159±81. Wiley, New York, USA. Phillips, B.F., Brown, P.A., Rimmer, D.W. & Reid, D.D. (1979) Distribution and dispersal of the phyllosoma larvae of the western rock lobster, Panulirus cygnus, in the south-eastern Indian Ocean. Aust. J. Mar. Freshwat. Res., 30, 773±83. Phillips, B.F., Pearce, A.F. & Litchfield, R.T. (1991) The Leeuwin Current and larval recruitment to the rock (spiny) lobster fishery off Western Australia. In The Leeuwin Current: An Influence on the Coastal Climate and Marine Life of Western Australia (Ed. by A.F. Pearce & D.I. Walker). J. R. Soc., WA., 74, 93±100. Pitcher, C.R. (1991) Research for the sustainable development of the tropical rock lobster fishery in the Torres Strait. In Sustainable Development for Traditional Inhabitants of the Torres Strait Region. Proceedings of the Torres Strait Baseline Study Conference (Ed. by D. Lawrence and T. Cansfield-Smith), pp. 253±9. Australian Government Printing Service, Canberra. Pitcher, C.R., Dennis, D.M. & Skews, T.D. (1997) Fishery-independent surveys and stock assessment of Panulirus ornatus in Torres Strait. Mar. Freshwat. Res., 48, 1059±67. Pitcher, C.R., Skewes, T.D., Dennis, D.M. & Prescott, H.J. (1991) Catastrophic mortality of breeding tropical rock lobsters. Proceedings of the International Crustacean Conference, Brisbane, 1990. Pitcher, C.R., Skewes, T.D., Dennis, D.M. & Prescott, J.H. (1992) Estimation of the abundance of the tropical lobster Panulirus ornatus in Torres Strait, using visual transect-survey methods. Mar. Biol., 131, 57±64. Punt, A.E. & Kennedy, R.B. (1997) Population modelling of Tasmanian rock lobster, Jasus edwardsii, resources. Mar. Freshwater Res., 48, 967±80. Punt, A.E., Kennedy, R.B. and Frusher, S.D. (1997) Estimating the size-transition matrix for Tasmanian rock lobster, Jasus edwardsii. Mar. Freshwat. Res., 48, 981±92. RLIAC (1993a) Rock Lobster Industry Advisory Committee. Management proposals for 1993/94 and 1994/95 western rock lobster season. Fisheries Management Paper No. 54, 25 pp. RLIAC (1993b) Rock Lobster Industry Advisory Committee Chairman's report to the Minister for Fisheries on management recommendations for 1993/94 and 1994/95 western rock lobster. Fisheries Management Paper No. 55, 22 pp. Staniford, A. (1986) An economic assessment of effort reduction measures in the southern rock lobster fishery. A discussion paper. Department of Fisheries, South Australia, June 1986. Treble, R.J. (1996) The southern rock lobster, Jasus edwardsii: fisheries biology and abundance estimation. Ph.D. thesis, University of Melbourne, Melbourne, Australia, 435 pp. Walters, C., Hall, N., Brown, R. & Chubb, C. (1993) A spatial model for the population dynamics and exploitation of the Western Australian rock lobster, Panulirus cygnus. Can. J. Fish. Aquat. Sci., 50, 1560±2. Winstanley, R.H. (1977) Biology of the southern rock lobster. Victorian Southern Rock Lobster Fishery Seminar Papers; Portland Arts Centre, 9±10 June 1977, Paper 3: 1±9.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 2

New Zealand's Rock Lobster Fisheries J. D. BOOTH National Institute of Water and Atmospheric Research, P.O. Box 14-901, Kilbirnie, Wellington 6003, New Zealand

2.1

Introduction

The New Zealand spiny or `rock' lobster fishery is based primarily on the red rock lobster, Jasus edwardsii. Less than 1% of commercial landings are of the green or `packhorse' rock lobster, J. verreauxi. Red rock lobsters occur from the Three Kings Islands in the north to the Auckland Islands in the south, at the Chatham Islands in the east (Fig. 2.1) (Kensler, 1967), and on surrounding banks. The areas supporting major fisheries are shown in Fig. 2.1. Jasus verreauxi are widespread (Booth, 1986), but are commercially taken mainly in waters off the north of the North Island. Deepwater spiny lobster, Projasus parkeri, are taken as an occasional bycatch in trawling (Webber & Booth, 1988) but are not marketed. Jasus edwardsii also occurs in southern Australia (where it was previously known as J. novaehollandiae) and in the Tasman Sea. Jasus verreauxi also occurs in eastern Australia. The location of other Jasus species and fisheries is described by Holthuis (1991). The New Zealand commercial rock lobster fishery is managed as three stocks: the North and South Island (including Stewart Island) red rock lobster stock (NSI); the Chatham Islands red rock lobster stock (CHI); and the packhorse rock lobster stock throughout New Zealand (PHC). Within the NSI stock, there are three substocks: northern (NSN), central eastern (NSC) and southern (NSS) (Fig. 2.1). Rock lobsters are also important customary and recreational species. Programmes of aquaculture and stock enhancement are at an experimental stage. This review draws on and updates that of Booth & Breen (1994).

2.2

History of the fishery

Midden remains show that rock lobsters were taken by Maori well before early European arrivals in the late eighteenth century (Leach & Anderson, 1979). Maori used diving, pots, and hoop nets (Best, 1929). The potential size of the commercial resource began to emerge during government-sponsored exploratory fishing early in the twentieth century. Commercial fisheries were first centred near large towns, and later small lobster canneries were set up for short periods near more remote grounds. The commercial fishery expanded greatly soon after World War II, when a large market developed in the USA for frozen tails. Peak catches for the NSI stock were 78

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Figure 2.1 Map of New Zealand showing places mentioned in text, the main Jasus edwardsii fishing areas (shaded), and the J. edwardsii Quota Management Areas (CRA1±CRA10). The North, South and Stewart Islands make up the NSI stock. The northern substock, NSN, comprises CRA1 and CRA2; the central NSC substock CRA3±CRA5; and the southern NSS substock CRA7 and CRA8. The Chatham Islands J. edwardsii stock, CHI, is CRA6. The PHC1 (J. verreauxi) stock is New Zealand-wide.

made in the mid-1950s. Overall landings for the NSI stock were relatively stable at about 4000±5500 t from 1960 until the late 1980s (see Booth & Breen, 1994, Fig. 2.2). However, the fishing effort required to take the catch increased steadily, and landings declined. Catches since the early to mid-1990s have, in some areas, been constrained through Total Allowable Commercial Catches (TACCs). The Chatham Islands fishery began in 1965, peaked in 1968 at over 6000 t, and has yielded 300±600 t per year since the early 1980s. Annual landings of J. verreauxi have generally been less than 100 t, and less than 25 t during the 1990s. Currently, there are about 500 boats in the commercial fishery, most of the rock lobsters caught being exported (Roberts, 1994). In 1998, the major markets were

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Hong Kong (770 t), China (710 t), Japan (500 t), and Taiwan (160 t) for live lobsters, and the USA for frozen tails (60 t). These exports were worth US $55 million FOB (NZ Seafood Industry Council, pers. comm.). Maori are engaged in the commercial fishery and also, under customary fishing rights, are presently estimated to take about 50 t per year. Recreational fishers are estimated to catch about 350 t per year. The two northern substocks appear to be well above BMSY, the biomass associated with the maximum sustainable yield, but the NSS stock appears to be well below it. For the CHI and PHC stocks, there is either insufficient information to decide on the status of the stock, or there are difficulties with interpretation of data.

2.3

Biology

Breen & McKoy (1988) list more than 300 published articles on J. edwardsii biology and fisheries in their annotated bibliography. Booth (1989) summarized the history of biological research and listed biological publications by subject and location for both commercial species. Sexual maturity in female J. edwardsii is reached at 60±120 mm carapace length (CL) (Annala et al., 1980), 3±10 years after settlement, depending on locality. Mating takes place in autumn, and eggs hatch in spring into the short-lived naupliosoma stage. Most of the phyllosoma development takes place in oceanic waters tens to hundreds of kilometres offshore over a period of at least 12±22 months (Lesser, 1978; Booth, 1994). Near the edge of the continental shelf, the final-stage phyllosoma metamorphoses into the settling stage, the puerulus. Puerulus settlement takes place mainly at depths less than 20 m, but not uniformly over time or between regions (Booth, 1994). Post-larval recruitment levels can fluctuate widely from year to year. Depending on locality, most female J. edwardsii take 7±11 years to reach legal size, and males 5±7 years. Most females in the south and south-east of the South Island do not breed before recruiting. Some rock lobsters undertake long-distance migrations in certain areas. During spring and early summer, variable but small proportions of small males and immature females move various distances against the current from the east and south coasts of the South Island towards Fiordland and south Westland (Booth, 1997). There is anecdotal evidence for some movements against the current northward along the east coast of the North Island. Almost all juvenile J. verreauxi migrate north along the east coast of the North Island as they approach sexual maturity. Most apparently then enter the main breeding population off Cape Reinga (Booth, 1986). Females breed for the first time at around 160±180 mm CL.

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81

Stock structure

Based on mitochondrial (mt) DNA and biochemical genetic studies, there is no evidence for genetic subdivision of J. edwardsii within the NSI stock (Smith et al., 1980; Booth et al., 1990; Ovenden et al., 1992). The long larval life and long-distance migrations in some areas presumably contribute to genetic uniformity. Gene flow from Australia may occur, but Australia is probably a much less important source of larvae for New Zealand than the New Zealand breeding stock itself. Subdivision of the NSI stock on other than genetic grounds has been considered (Booth & Breen, 1992; Bentley & Starr, 2000). There are geographical discontinuities in the frequency of antennal banding, size at onset of maturity in females, migratory behaviour, fishery catch and effort patterns, phyllosoma abundance, and puerulus settlement levels. These were important in fixing the substock boundaries. Although considered separately for stock assessment purposes, the CHI stock may depend heavily upon NSI as a source of larval recruitment (Lesser, 1978). Jasus verreauxi forms one stock centred in northern New Zealand (Booth, 1986). From examination of mtDNA it appears to be genetically discrete from the Australian stock (Brasher et al., 1992).

2.5

Abundance of early life-history stages

Mid- and late-stage phyllosomas of J. edwardsii have, at least in recent years, been much more abundant off the east coast of the North Island south of East Cape than elsewhere around New Zealand. A very extensive larval pool (about 500  1500 km) is evident there (Booth et al., 1999), the high larval abundance probably determined by several factors including high annual fecundity (about 100 000 per female), the many years (about 8) of egg production before females recruit, and the oceanography. The region coincides with the East Cape Current system, a conspicuous area of circulation within which lies the Wairarapa Eddy. This eddy entrains larvae and helps to retain them nearshore (Chiswell & Booth, 1999). Puerulus settlement of J. edwardsii over the past 15 years has also been much higher in this area than in most others (Booth, 1994; Booth et al., 1999). Annual levels of settlement are correlated among several sites along the east coast of New Zealand, indicating that the factors which drive larval recruitment influence large areas of the coastline at any one time. The years 1981, 1983, 1987, 1991/92, and 1998 were moderate to high settlement years in the North Island from East Cape south. The settlement pattern is correlated with the frequency of southerly storminess, possibly through Ekman surface drift. There is a strong relation between puerulus settlement and subsequent juvenile abundance of J. edwardsii at Stewart Island and Wellington (Breen & Booth, 1989; Booth et al., 1999). There are significant correlations in CRA7, where the minimum legal size (MLS) is smaller than in other areas, between various indices of settlement

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and fishery landings (mainly immature animals) 4±5 years later. Similarly, recent trends in catch per unit effort (CPUE) in the commercial fishery along the east coast of central New Zealand are consistent with the pattern of previous settlement.

2.6

Management

Rock lobster became a limited-entry fishery for commercial fishers during 1980/81 (Annala, 1983). The next major change was on 1 April 1990, when each of 10 Quota Management Areas (QMAs; CRA1±CRA10, Fig. 2.1, each with a separate fishstock, in most instances corresponding to the previous Controlled Fishery Areas) for J. edwardsii was allocated a TACC and each fisher received a transferable term quota based on their recent catch history. (There is no commercial rock lobster fishery in CRA10, which was established for administrative reasons.) A quota is valid for 25 years and is tradeable (Annala, 1996). Commercial fishers must file records of catch, effort and fishing area for each day fished. The sum of the TACCs for the NSI stock of J. edwardsii was set at 3200 t for the 1990/91 fishing year. This was steadily reduced year by year until it reached 2382.5 t in 1995/96, but it increased to 2589.5 t in 1999/2000, following increases in TACC in CRA2±CRA5 (but decreases in CRA7 and CRA8). There are separate TACCs for the CHI and PHC stocks. The CHI TACC is now 360 t, after a high of 530.6 t in 1993/94. The PHC stock is the New Zealand-wide Fishstock PHC1, with a current TACC of 40.3 t, which is not attained. Total allowable catches (TACs) for J. edwardsii were set for the first time in 1997/98 for three QMAs, which is a new requirement under the 1996 Fisheries Act. TACs include not only the commercial catch, but also the customary, recreational, illegal and unreported catches. Fisheries in New Zealand must be managed so that stocks are maintained near BMSY. During each year, the Rock Lobster Working Group reviews any new information on stock structure, productivity and abundance, updates the status of each fishstock with respect to MSY and reports on the sustainability of catches. The group's conclusions are presented to the Mid-Year Fishery Assessment Plenary and are publicly available (e.g. Annala & Sullivan, 1998). Another group with representation from all sectors of the fishery, the National Rock Lobster Management Group, advises the Minister on management of the fishery. This has allowed the development of management proposals in a much less confrontational manner. Traps are not restricted in number or type, except that they must have gaps to allow escape of small lobsters. The most common trap is single-chambered and rectangular, with the largest dimension up to 1.2 m. Egg-bearing females and softshelled lobsters must be returned to the sea. Lobsters are landed live, except in CRA8 where many vessels fish for more than a day at a time and lobsters may be tailed at sea. There are seasonal restrictions on fishing only in CRA3, CRA6 and CRA7.

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Until 1988, the MLS was based on tail length: 152 mm for J. edwardsii and 216 mm for J. verreauxi. These corresponded roughly to 100 and 93 mm CL for male and female J. edwardsii, respectively, and to 163 and 155 mm CL for male and female J. verreauxi. Since 1988, the MLS for J. edwardsii has mainly been based on tail width, measured between the primary spine tips on the second abdominal segment. The change was designed to base MLS on a more solid body dimension. The MLS was 54 mm for males and 58 mm for females, based on morphometric conversions (Breen et al., 1988), but the female MLS was increased for most areas to 60 mm tail width in mid-1992. Special conditions applied to CRA3 since the 1993/94 fishing year have permitted commercial fishers to retain smaller males for part of the year (Breen & Kendrick, 1997a). Recent legislative change has allowed fishers to retire quota in the commercial fishery and, every year for every tonne retired, to take 40 000 (30 kg) pueruli and young juveniles for ongrowing. Recreational fishers use tail width (54 and 60 mm for males and females, respectively) for red rock lobsters and tail length (216 mm) for packhorse. No licence or reporting is necessary, but there is a bag limit of six lobsters per fisher per day. There are 15 widely distributed, mainly small (<1000 ha) marine protected areas, where no marine life, including lobsters, may be taken. Their total area is 760 000 ha; the first established was near Leigh in 1975, and the largest is the Kermadec Islands Marine Reserve (750 000 ha), north-east of mainland New Zealand. The greatest immediate benefit of these areas for lobster fisheries may be through cross-boundary movements of mainly large male lobsters into surrounding fished areas. Industry employs its own research scientists who contribute to the stock assessments. There is a monthly industry journal, Seafood New Zealand, in which management decisions are reported and analysed and research results made available.

2.7

Stock assessment

Catches have been recorded for NSI stock rock lobsters since the 1930s. Effort estimates are available since 1945 as the number of vessels fishing, and more recently as traps lifted (e.g. Sanders, 1988). Estimates of customary, recreational, illegal and unreported catches have also been made. Early stock assessments used surplus-production analyses (Saila et al., 1979; Annala & Esterman, 1986; Fogarty & Murawski, 1986; Breen & Stocker, 1993; Breen & Kendrick, 1994, 1995a, b, 1997b, 1998a) based on this long series of fishery data. Later assessments used age-structured models (e.g. Breen & Kendrick, 1997b, 1998b). The NSI substocks are now assessed using length-based models. Decision rules (e.g. Breen et al., 1994; Starr et al., 1997) based on the CPUE data dictate whether or

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not assessment of a substock is made. For NSS, the decision rule also directs whether or not the TACC is adjusted (Annala & Sullivan, 1998). The length-based models are dynamic; they are fitted to CPUE and to length frequency data; growth is represented through a transition matrix which specifies the probability of animals in every length class moving to any length class of the same size or larger in the next step (Annala & Sullivan, 1998). Five year forward projections are made, based on current TACCs and on increased or decreased TACCs. A suite of performance indicators is used as a measure of the status and risk for each substock. The two northern substocks appear to be well above BMSY, but NSS appears to be well below it. As a result, there were recent changes in some TACCs, as mentioned earlier. The yield-per-recruit estimates of Saila et al. (1979) were revised by Annala & Breen (1989) and Breen & Kendrick (1994), who also examined egg-per-recruit. Egg production estimates varied from very low in southern areas to reasonably high off the east coast of North Island. An intensive research programme of catch sampling in major areas of lobster fishing begun in 1989 has been supplemented with, or in places replaced by, a voluntary fisher logbook programme since 1993 (Starr & Vignaux, 1997). These provide a time series of size and sex composition data that allow exploitation rates to be monitored through time, and other data such as maturity of females and the effect of soak time on catch. The programme also collects detailed CPUE information for tracking stock responses to management actions.

2.8

Recent changes in the commercial fishery

The major management action in the recent history of the J. edwardsii fishery has been the introduction of the individual quota system in 1990. TACCs, with individual quotas, have provided managers with the means to reduce catches in order to allow stocks to rebuild, and has also given fishers a greater stake in the regulation of the fishery (Annala, 1996). Because the stock had been seriously depleted and TACCs too high in some areas, quotas were not immediately attained. More recently in most QMAs, quotas have been taken early in the fishing year, the TACCs were met and the fishery is rebuilding. Illegal catches are thought to be less of a problem at the time of writing than they were in the early 1990s, but are still estimated to be about 400 t a year. The establishment of special conditions for CRA3 is evidence of the trend towards more regional management of rock lobsters within the quota system. No new significant fishery areas for J. edwardsii have been discovered since the last review of the fishery. Rock lobster occur to depths of at least 275 m, but the main depth range fished is 10±100 m. Boat sizes remain about the same size, but there is now a greater proportion of larger, planing hulls over 10 m in length. There is increasingly widespread use of colour depth sounding and position-plotting technology.

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Trapping is still the major fishing method; commercial diving is confined to parts of the Chatham Islands. Trap designs remain the same. Vessels fish up to 400 traps, but more commonly 50±150, compared with 40±100 in the early 1980s. Fishing is still conducted mostly by day-boats, except in CRA8. Since 1985, an increasing volume of rock lobster has been exported overseas live; in 1998 this figure was 2250 t. Previously, most lobsters were exported as frozen tails to the USA, exports of tails now being only 80 t, most to the USA. The filling of quotas early in the season in northern and central parts of the NSI stock in recent years has meant that these fisheries have become largely winter and male based. (Females are egg bearing in winter.) This has led to high returns per unit weight on the Asian live market, New Zealand lobsters being available before other southern temperate countries can supply them. `Highgrading` ± selection during fishing of particular sized lobsters which have the highest market value at the time ± is still thought to take place, but the extent is unknown.

2.9

Current problems and research questions

The potential for widespread dispersal during the long larval life makes it difficult to determine larval sources and recruitment mechanisms. What areas are the most important larval sources, and do they vary from year to year? Fifteen years of puerulus settlement data, along with juvenile survey and catch sampling data, are leading to predictions of fishery recruitment trends. For much of the east coast of New Zealand, the last moderate or high settlement years were 1991, 1992 (1991/93 for the north-east coast of the South Island) and 1998. The NSN and NSC substocks appear to be rebuilding but it is not clear how much of this recovery has come about through the conservative TACCs and how much is due to any recruitment pulse from the high settlement in the early 1990s. The NSS substock appears to continue to decline and the settlement data offer no respite from that. The fishery has become largely a winter, male-based one in many areas. This means that there are likely to be fewer large males and more large females. What effect will this have on fertilization rates? This question, along with the associated issue of sperm limitation affecting egg production, is being investigated (MacDiarmid et al., 1998, 1999). Although commercial landings are well estimated, much less precise information is available for annual recreational and customary catches, and particularly illegal catches. Also poorly known is the mortality of discards during fishing. These all have an important bearing on the setting of TACs. The length-structured models are sensitive to growth inputs, and many of the growth data available for J. edwardsii come from the 1970s and 1980s. Since 1995, extensive new taggings have begun in many QMAs using T-bar tags applied dorsally between the carapace and the abdomen over a wide size range of lobsters.

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The destination of much of New Zealand's lobster is the live Asian market and this has generated research into live transport issues and the measurement of stress (Taylor et al., 1997). The need for a lively, intact product which can cope with the many hours out of water required to reach Asian destinations in good condition has also led to the development of a code of practice for handling rock lobster at sea and on shore (Harvie, 1993). There is research into phyllosoma culture, both Jasus species having now been cultured to settlement (Kittaka et al., 1988, 1997). Is aquaculture a way to further production? Hatchery production of post-larvae might be aimed at onshore ongrowing or ongrowing in sea cages, or for release in the wild. Small-scale experimental ongrowing of pueruli and young juveniles has now extended to commercial-scale collections of young settled lobsters for ongrowing onshore to marketable size in exchange for retired quota from the commercial fishery, but collection costs have been high and there have been problems with lobster mortality in recirculating water systems. The aim is to produce lobsters of optimal market size, a size which may or may not be over the MLS enforced in the wild fishery. Can wild production be increased by overcoming population survival bottlenecks, such as at settlement, or through habitat enhancement using artificial structures? To answer this, it needs to be demonstrated that artificial shelter does not simply concentrate animals but actually improves survival. World-wide, there is pressure to secure more areas as no-take reserves. The purposes of these are several, including, if widespread enough, providing a significant source of recruitment and negating any possible genetic consequences from fisheries selection in the harvested stock. Debate continues on their efficacy for the New Zealand rock lobster fishery.

2.10

Summary

The New Zealand rock lobster fishery is based on two species, the most important by far being the red rock lobster J. edwardsii, and is fully developed with respect to all stocks and substocks. It is tightly regulated and is the focus of considerable research. Most populations appear to be rebuilding. Possible opportunities for increased production lie with rebuilding all stocks to or above BMSY, reducing the impacts of survival bottlenecks, seeding of recruitment-limited places and aquaculture.

References Annala, J.H. (1983) The introduction of limited entry. The New Zealand rock lobster fishery. Mar. Pol., 7, 101±8. Annala, J.H. (1996) New Zealand's ITQ system: have the first eight years been a success or a failure? Rev. Fish. Biol., 6, 43±62.

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Annala, J.H. & Breen, P.A. (1989) Yield- and egg-per-recruit analyses for the New Zealand rock lobster, Jasus edwardsii. N.Z. J. Mar. Freshwat. Res., 23, 93±105. Annala, J.H. & Esterman, D.B. (1986) Yield estimates for the New Zealand rock lobster fishery. In North Pacific Workshop on Stock Assessment and Management of Invertebrates (Ed. by G.S. Jamieson & N. Bourne). Can. Spec. Pub. Fish. Aquat. Sci., 92, 347±58. Annala, J.H. & Sullivan, K.J. (Comps.) (1998) Report from the Mid-Year Fishery Assessment Plenary, November 1998: stock assessments and yield estimates. Unpublished report held in National Institute of Water and Atmospheric Research library, Greta Point, Wellington, New Zealand. Annala, J.H., McKoy, J.L., Booth, J.D. & Pike, R.B. (1980) Size at the onset of sexual maturity in female Jasus edwardsii (Decapoda: Palinuridae) in New Zealand. N.Z. J. Mar. Freshwat. Res., 14, 217±27. Bentley, N. & Starr, P.J. (2000) An examination of stock definitions for the New Zealand rock lobster fishery. N.Z. Fish. Assessment Rep. N.Z. Ministry of Fisheries. Best, E. (1929) Fishing methods and devices of the Maori. Dominion Mus. Bull., No. 12. Government Printer, Wellington, New Zealand. Booth, J.D. (1986) Recruitment of packhorse rock lobster Jasus verreauxi in New Zealand. Can. J. Fish. Aquat. Sci., 43, 2212±20. Booth, J.D. (1989) History of biological research into the rock lobsters of New Zealand. In Workshop on Rock Lobster Ecology and Management (Ed. by B.F. Phillips). CSIRO Mar. Lab. Rep., 207, 35±52. Booth, J.D. (1994) Jasus edwardsii larval recruitment off the east coast of New Zealand. Crustaceana, 66, 295±317. Booth, J.D. (1997) Long-distance movements in Jasus spp. and their role in larval recruitment. Bull. Mar. Sci., 61, 111±28. Booth, J.D. & Breen, P.A. (1992) Stock structure in the New Zealand red rock lobster, Jasus edwardsii. N.Z. Fish. Assessment Res. Doc. No. 92/20. N.Z. Ministry of Agriculture and Fisheries. Booth, J.D. & Breen, P.A. (1994) The New Zealand fishery for Jasus edwardsii and J. verreauxi. In Spiny Lobster Management (Ed. by B.F. Phillips, J.S. Cobb & J. Kittaka), pp. 64±75. Blackwell Scientific Publications, Oxford, UK. Booth, J.D., Forman, J.S., Stotter, D.R., Bradford, E., Renwick, J. & Chiswell, S.M. (1999) Recruitment of the red rock lobster, Jasus edwardsii, with management implications. N.Z. Fish. Assessment Res. Doc. No. 99/10. N.Z. Ministry of Fisheries. Booth J.D., Street R.J, & Smith P.J. (1990) Systematic status of the rock lobsters Jasus edwardsii from New Zealand and J. novaehollandiae from Australia. N.Z. J. Mar. Freshwat. Res., 24, 239± 49. Brasher, D.J, Ovenden, J.R., Booth J.D. & White, R.W.G. (1992) Genetic subdivision of Australian and New Zealand populations of Jasus verreauxi (Decapoda: Palinuridae) ± preliminary evidence from the mitochondrial genome. N.Z. J. Mar. Freshwat. Res., 26, 53±8. Breen, P.A. & Booth, J.D. (1989) Puerulus and juvenile abundance in the rock lobster Jasus edwardsii at Stewart Island, New Zealand. N.Z. J. Mar. Freshwat. Res., 23, 519±23. Breen, P.A. & Kendrick, T.H. (1994) Surplus production and yield-per-recruit analyses for the red rock lobster (Jasus edwardsii) fishery. N.Z. Fish. Assessment Res., Doc. No. 94/5. N.Z. Ministry of Agriculture and Fisheries. Breen, P.A. & Kendrick, T.H. (1995a) The 1994 stock assessment for the red rock lobster (Jasus edwardsii) fishery. N.Z. Fish. Assessment Res. Doc., No. 95/23. N.Z. Ministry of Agriculture and Fisheries. Breen, P.A. & Kendrick, T.H. (1995b) How useful is surplus-production analysis for assessing the red rock lobster (Jasus edwardsii) fishery? N.Z. Fish. Assessment Res. Doc., No. 95/24. N.Z. Ministry of Agriculture and Fisheries.

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Breen, P.A. & Kendrick, T.H. (1997a) A fisheries management success story: the Gisborne, New Zealand, fishery for red rock lobsters (Jasus edwardsii). Mar. Freshwat. Res., 48, 1103±10. Breen, P.A. & Kendrick, T.H. (1997b) Production analyses for two substocks of the New Zealand red rock lobster (Jasus edwardsii) fishery. N.Z. Fish. Assessment Res. Doc., No. 97/4. N.Z. Ministry of Fisheries. Breen, P.A. & Kendrick, T.H. (1998a) An evaluation of surplus production analysis for assessing the fishery for New Zealand red rock lobsters (Jasus edwardsii). In Proceedings of the North Pacific Symposium on Invertebrate Stock Assessment and Management (Ed. by G.S. Jamieson & A. Campbell), pp. 213±23. Department of Fisheries and Oceans, Nanaimo, Canada. Breen, P.A. & Kendrick, T.H. (1998b) The 1996 assessment for the New Zealand red rock lobster (Jasus edwardsii) fishery. N.Z. Fish. Assessment Res. Doc., No. 98/13. N.Z. Ministry of Fisheries. Breen, P.A. & McKoy, J.L. (1988) An annotated bibliography of the red rock lobster, Jasus edwardsii, in New Zealand. N.Z. Fish. Occ. Pub., No. 3. N.Z. Ministry of Agriculture and Fisheries. Breen, P.A. & Stocker, M. (1993) Evaluating the consequences of constant catch levels on the red rock lobster, Jasus edwardsii, population of New Zealand. In Proceedings of the International Symposium on Management Strategies for Exploited Fish Populations (Ed. by G. Kruse, D.M. Eggers, R.J. Marasco, C. Pautzke & T.J. Quinn) Alaska Sea Grant College Program Report No. 93±02, pp. 39±59. University of Alaska, Fairbanks, USA. Breen, P.A., Booth, J.D. & Tyson, P.J. (1988) Feasibility of a minimum size limit based on tail width for the New Zealand rock lobster Jasus edwardsii. N.Z. Fish. Tech. Rep., No. 6. N.Z. Ministry of Agriculture and Fisheries. Breen, P.A., Kendrick, T.H., Starr, P.J. & Maunder, M.N. (1994) Results of the implementation of the rock lobster decision rule in 1994. N.Z. Fish. Assessment Res. Doc., No. 94/3. N.Z. Ministry of Agriculture and Fisheries. Chiswell, S.M. & Booth, J.D. (1999) Rock lobster Jasus edwardsii larval retention by the Wairarapa Eddy off New Zealand. Mar. Ecol. Progr. Ser., 183, 227±40. Fogarty, M.J. & Murawski, S.A. (1986) Population dynamics and assessment of exploited invertebrate stocks. In North Pacific Workshop on Stock Assessment and Management of Invertebrates (Ed. by G.S. Jamieson & N. Bourne) Can. Spec. Pub. Fish. Aquat. Sci., 92, 228±44. Harvie, R. (1993) A Code of Practice for Rock Lobster Products. New Zealand Fishing Industry Board, Wellington, New Zealand. Holthuis, L.B. (1991) Marine lobsters of the world: an annotated and illustrated catalogue of species of interest to fisheries known to date. FAO Fish. Syn., 125, (FAO Species Catalogue 13). Kensler, C.B. (1967) The distribution of spiny lobsters in New Zealand waters (Crustacea: Decapoda: Palinuridae). N.Z. J. Mar. Freshwat. Res., 1, 412±20. Kittaka, J., Iwai, M. & Yoshimura, M. (1988) Culture of a hybrid of spiny lobster genus Jasus from egg stage to puerulus. Nippon Suisan Gakkaishi, 54, 413±17. Kittaka, J., Ono, K. & Booth, J.D. (1997) Complete development of the green rock lobster, Jasus verreauxi from egg to juvenile. Bull. Mar. Sci., 61, 57±71. Leach, B.F. & Anderson, A.J. (1979) Prehistoric exploitation of crayfish in New Zealand. In Birds of a Feather: Osteological and Archaeological Papers from the South Pacific in Honour of R.J. Scarlett (Ed. by A. Anderson). British Archaeological Reports, Int. Ser., 62, 141±64. Lesser, J.H.R. (1978) Phyllosoma larvae of Jasus edwardsii (Hutton) (Crustacea: Decapoda: Palinuridae) and their distribution off the east coast of the North Island, New Zealand. N.Z. J. Mar. Freshwat. Res., 12, 357±70. MacDiarmid, A.B., Butler, M.J. & Stewart, R. (1998) Is big always better? The effect of mate size on female fecundity in spiny lobsters. Seafood N.Z., July, 53±4. MacDiarmid, A., Stewart, R. & Oliver, M. (1999) Jasus females are particularly vulnerable to mate availability. Lobster Newslett., 12, 1±2.

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Ovenden, J.R., Brasher, D.J. & White, R.W.G. (1992) Mitochondrial DNA analyses of the red rock lobster Jasus edwardsii supports an apparent absence of population subdivision throughout Australasia. Mar. Biol., 112, 319±26. Roberts, P.R. (1994) Export marketing of Australian and New Zealand rock lobster. In Spiny Lobster Management (Ed. by B.F. Phillips, J.S. Cobb & J. Kittaka), pp. 510±16. Blackwell Scientific Publications, Oxford, UK. Saila, S.B., Annala, J.H., McKoy, J.L. & Booth, J.D. (1979) Application of yield models to the New Zealand rock lobster fishery. N.Z. J. Mar. Freshwat. Res., 13, 1±11. Sanders, B. (1988) The 1986 New Zealand rock lobster landings. N.Z. Fish. Data Rep., No. 32. N.Z. Ministry of Agriculture and Fisheries. Smith, P.J., McKoy, J.L. & Machin, P.J. (1980) Genetic variation in the rock lobsters Jasus edwardsii and Jasus novaehollandiae. N.Z. J. Mar. Freshwat. Res., 14, 55±63. Starr, P.J. & Vignaux, M. (1997) Comparison of data from voluntary logbook and research catchsampling programmes in the New Zealand lobster fishery. Mar. Freshwat. Res., 48, 1075±80. Starr, P.J., Breen, P.A., Hilborn, R.H. & Kendrick, T.H. (1997) Evaluation of a management decision rule for a New Zealand rock lobster substock. Mar. Freshwat. Res., 48, 1093±101. Taylor, H.H., Paterson, B.D., Wong, R.J. & Wells, R.M.G. (1997) Physiology and live transport of lobsters: report from a workshop. Mar. Freshwat. Res., 48, 817±22. Webber, W.R. & Booth, J.D. (1988) Projasus parkeri (Stebbing, 1902) (Crustacea, Decapoda, Palinuridae) in New Zealand and description of a Projasus puerulus from Australia. Nat. Mus. N.Z. Rec., 3, 81±92.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 3

Fisheries for Spiny Lobsters in the Tropical Indo-West Pacific J.L. MUNRO International Centre for Living Aquatic Resources Management (ICLARM), Caribbean/Eastern Pacific Office, Suite 158, Inland Messenger Service, Road Town, Tortola, British Virgin Islands

3.1

Introduction

The species of spiny lobster (genus Panulirus) inhabiting the tropical waters of the Indo-West Pacific have distributions which range, for the most part, from East Africa and the Red Sea, through the south-east Asian archipelagoes to French Polynesia. In higher latitudes the species composition changes and temperate water species have much more restricted ranges. Abundances are generally low and few countries within this vast region have highvolume fisheries. However, the high value of the product ensures that in almost all countries basic distribution systems exist for transporting lobster tails to the major urban centres, some of the product being subsequently exported.

3.1.1

Species and habitats

Six commercially important species in the genus Panulirus occur in the shallow waters of the tropical Indo-West Pacific (De Bruin, 1969; George, 1972; Bhatia, 1974; Williams, 1988; Pitcher, 1993). Panulirus penicillatus has by far the widest range, from East Africa and the Red Sea to the Galapagos Islands and Mexico (Williams, 1988). Panulirus polyphagus is essentially an Asian species, reported from Sri Lanka to Thailand, and as far eastwards as Papua New Guinea and Northern Australian (Pyne, 1970), and is confined to muddy soft-bottom shelves ± a habitat which is generally absent from the islands of Oceania or of the Indian Ocean. Panulirus longipes longipes is found in the Indian Ocean and extends eastwards at least as far as the Philippines (Juinio & Gomez, 1986). Further eastwards within the Pacific, the stripe-legged subspecies P. longipes femoristriga has been reported from all areas. Panulirus versicolor is fairly widespread in the Pacific and P. homarus is discontinuously distributed through the Indian Ocean to Papua New Guinea, northern Australia, New Caledonia and French Polynesia. Panulirus ornatus extends as far eastwards as Fiji (George, 1972). 90

Fisheries for Spiny Lobsters in the Tropical Indo-West Pacific

91

In addition to the six common species, P. pascuensis has been reported only from Easter Island and Pitcairn. Species of the genera Justita and Puerulus are generally found in deep water and are small and of no commercial value (Williams, 1988). The works of De Bruin (1969), Berry (1971), George (1972) and Bhatia (1974) have clearly identified the habitats of the six principal species, but there is a broad degree of overlap in their preferences. For example, George (1972) reported that P. homarus, P. penicillatus and P. longipes had been taken concurrently from a reef cave in French Polynesia. Soft-bottom habitats are exclusively occupied by P. polyphagus, which is not found on reefs. Panulirus ornatus lives in turbid, relatively calm waters with strong currents on the shelves of large islands and continents and has not been reported from atolls. Panulirus penicillatus, the most widely distributed species, occupies high-energy habitats of windward reefs of islands and atolls. Panulirus homarus also occupies relatively high-energy turbid, inshore habitats (Pyne, 1970; Berry, 1971; George, 1972) and De Bruin (1969) reported that this species outnumbered P. penicillatus on sandstone reefs in Sri Lanka and appeare to avoid coral formations. In more sheltered or deeper coralline areas P. longipes longipes predominates, while P. versicolor will be found in calm lagoonal areas of branching corals, and the juveniles are often found in areas of reduced salinity (Prescott, 1988)

3.1.2

Fisheries

A limited variety of fishing methods are used to capture spiny lobsters in the region, most being variants on either capture by hand or by spearing. Some are taken incidentally in tangle nets and some are trapped. Incidental catches of P. polyphagus are taken by trawlers in south-east Asia and Papua New Guinea and the P. ornatus stock in the Torres Strait area used to be targeted by trawlers during their annual spawning migration across the Gulf of Papua before this was prohibited (see Phillips et al., Chapter 1). The question of trapping is of particular interest. All temperate species of spiny lobsters are principally exploited by means of traps. the Hawaiian fishery for P. marginatus and P. penicillatus is based entirely on traps (see Chapter 4); the Caribbean stocks of P. argus and P. guttatus are highly vulnerable to wire-mesh fish traps or slatted lobster pots (Ehrhardt, Chapter 8; Briones-FourzaÂn & LozanoAÂlvarez, Chapter 9) and the Western Australian fishery for P. cygnus is based on trap fishing. However, in the central parts of the tropical Pacific no commercial trap fisheries exist. Mutagyera (1975) reported that fishing for spiny lobsters around Zanzibar was `by skin diving and harpooning'and that `only a few enter the local ``Dema'' traps set for fish'. Juinio & Gomez (1986) report that P. penicillatus and P. longipes longipes are commonly caught in traps in Samar on the Pacific coast of the Philippines, with occasional catches of P. versicolor and P. ornatus. the traps are cylindrical bamboo

92

Spiny Lobsters: Fisheries and Culture

structures with an entrance at either end, which are staked in position in surge channels, principally during the calm season. At the height of the north-east trade wind season, these habitats are usually inaccessible but trap fishing gives way to spear fishing at the height of the calm (south-west monsoon) season. However, they suggested that this was mostly because of interference with traps by divers and that improved trap designs should be investigated because traps would provide a better basis for management of the fishery. Charbonnier & Crosnier (1961) reported that P. longipes longipes could be captured in traps in Madagascar, whereas P. versicolor and P. ornatus were never so captured. In Sri Lanka, De Bruin (1969) reported that P. versicolor `avoided entering traps, no matter what design was used' but P. penicillatus could be captured in traps. In Palau, where fishing is exclusively by spearing, `P. versicolor could not be trapped readily'(MacDonald, 1982). In Fiji in 1961, attempts were made to use New Zealand lobster traps for capturing P. versicolor and P. penicillatus and, in 1963, a commercial group tested many pot designs in an area where P. versicolor were abundant, but both attempts were unsuccessful (George, 1972). George (1972) reported that lobsters, presumably P. penicillatus, used to be captured in small (46 cm) banana-shaped wicker baskets in Western Samoa. A similar trap was used in American Samoa. He also reported that in 1965, tests with rectangular traps (1.2  0.9  0.9) made of 7.6  10.2 cm welded metal mesh and baited with tuna heads produced catches of about 15 large P. penicillatus per haul in American Samoa. the experiment was terminated when the traps were stolen. No information was given on the depth at which the traps were set. A beehive-shaped pot, a `funaki', made of vines with a single opening in the top, was traditionally used in Tonga (George, 1972). these traps were placed in the landward ends of surge channels, baited with short-spined sea urchins and partially covered with limestone slabs. they appear to no longer be used (Prescott, 1990). Tasmanian beehive rock lobster pots were tested in relatively sheltered areas and yielded modest catches of P. longipes longipes. However, they were not tested in areas frequented by P. penicillatus (George, 1972). Felfoldy-Ferguson (1988) used Antillean fish traps to sample fish stocks on the Tongatapu shelf and captured scyllarid lobsters but no palinurids. Successful trapping of P. penicillatus and P. longipes longipes at depths between 19 and 122 m has been reported in Vanuatu, using beehive, wicker or cane pots, baited with chitons or sea urchins. Best catches were several hundred lobsters per month from 20 traps, set only during the neap tides (George, 1972). No indigenous trapping methods for spiny lobsters have been reported from Papua New Guinea, Solomon Islands, Micronesia (MacDonald, 1979) or French Polynesia. It is apparent that where exposed reef flats are accessible, gathering P. penicillatus by hand or by spearing has generally taken precedence over trap fishing and that the availability of skin-diving equipment has probably been a factor in the abandoning

Fisheries for Spiny Lobsters in the Tropical Indo-West Pacific

93

of traditional trapping methods. It is also clear that various types of baited traps could be expected to yield harvests of P. penicillatus and P. longipes in many areas but that P. versicolor, P. homarus and P. ornatus have never been successfully trapped on a regular basis anywhere in the region. The particular advantage of traps and the capture by hand over spearing is that the catch is unharmed and can be retained alive in cages in lagoons; in the case of P. penicillatus for up to 6 weeks (Prescott, 1980) and thereafter sold in bulk, possibly for live export. For these reasons, further investigations into trap-fishing technologies would appear to merit attention.

3.1.3

Biology

Other than the extensive work done in the Torres Strait and Gulf of Papua on P. ornatus (see references in Phillips et al., Chapter 1), there have been singularly few detailed biological studies of the principal species in the tropical Indo-Pacific. Zann (1984) undertook a substantial biological study in Tonga and also accumulated length-frequency data for P. penicillatus and P. longipes which were analysed by Munro (1988) to derive estimates of growth and mortality parameters. MacDonald (1979, 1982) undertook wide-ranging studies of P. penicillatus, P. versicolor and P. longipes femoristriga in Palau, and Prescott (1980, 1988) studied aspects of the biology of P. penicillatus in the Solomon Islands. Because of the sparsity of data there have been singularly few assessments made of the status of any stocks. In the case of P. penicillatus, estimates of growth and mortality have been made for stocks in Enewetak (Ebert & Ford, 1986), Tonga (Munro, 1988) and Solomon Islands (Prescott, 1988) and for P. longipes in Tonga (Munro, 1988). Rongmuangsart & Luvira (1973) present a comprehensive account of the biology of P. polyphagus in Thailand and Berry (1970) of the reproductive biology of P. homarus in South Africa. Mohammed & George (1968) tagged and recaptured P. homarus in India but obtained remarkably low estimates of growth rates. Pitcher (1993) has presented a set of yield-per-recruit estimates for P. penicillatus for Solomon Islands, Tonga, Samoa and the Phillipines, based on a variety of data sources, and has extensively reviewed available biological data on the species found in the South Pacific.

3.1.4

Stocks and populations

Data on landings and catch rates of tropical spiny lobsters are extremely sparse, are not usually partitioned by species and consequently yield very little information upon which management measures could be based. Table 3.1 shows data pertaining

94

Spiny Lobsters: Fisheries and Culture

Table 3.1 Landings (t whole weight) of Panulirus spp. in the tropical Indo-West Pacific: 1984±1996 1984

1987

1990

1993

1996

East Africa

Mozambique Tanzaniaa Kenya Somalia

++ ++ 55 552

++ ++ 117 500

675 ++ 74 543

756 ++ 47 350

463 ++ 117 370

Red Sea/Middle East

Ethiopia Djibouti Sudan Saudi Arabia Yemen

? 4 + 24 669

? 5 + ? 1248

? + + 5 1704

? + + 8 1021

? + + 13 345

Oman Pakistan India Sri Lanka

? 799 ? +

1557 214 ? +

1499 470 ? +

701 507 ? +

904 724 ? +

Burma Thailand Malaysia Singapore

+ + 392 94

+ + 628 89

+ + 691 110

+ + 1118 136

+ + 814 32

Indonesia Cambodia Vietnam Phillipines

473 ? ? 1361

965 ? ? 591

826 ? ? 612

1208 ? ? 1238

3700 ? ? 856

131 612 + + +

189 504 + + +

310 298 + + +

358 341 + + +

390 350 + + +

Mauritius N.W. Australia Palau Northern Marianas

60 2 2 5

48 2 5 2

14 + 5 2

13 + 5 1

12 + 8 2

Guamb Fed. States of Micronesia Marshall Islands N.E. Australia

1 7 + 2

2 10 + 2

+ 10 + 211

+ 10 + 174

+ 5 + 168

115 ++ +

138 ++ +

80 ++ +

90 ++ +

100 ++ +

South Asia

South-east Asia

Indian Ocean

Oceania

Madagascar Reunion Comoros Maldives Seychelles

Papua New Guineac Solomon Islands Vanuatu

Fisheries for Spiny Lobsters in the Tropical Indo-West Pacific Table 3.1

95

continued

Oceania (cont.)

Kiribatib Tuvalub Fiji New Caledonia Western Samoa American Samoab Tongad Cook Islands French Polynesia

Totals

1984

1987

1990

1993

1996

1 1

1 1

+ +

+ +

+ +

92 13 + 25

136 50 + 25

360 12 + ++

96 6 + ++

105 17 + ++

24 + 2 >5811

++ + 2 >7334

++ + 4 >8952

++ + 3 >8790

++ + 20 >10 115

Source: FAO (1998) plus other sources.a±d +, Modest catches; ++, substantial catches of unknown magnitude. a About 4 t/year around Zanzibar in 1973 (Mutagyera, 1975). b Pitcher (1993). c Australian Fisheries Service. d Zann (1984).

to the Indo-West Pacific region. Some significant producers have no recorded catches in the FAO statistics (FAO, 1998). Prescott (1988) suggested that catch rates in terms of catch per person-hour, either by swimming or wading along the reef edge at appropriate tides, should give reasonable estimates of relative abundance of stocks (other than P. ornatus). Depletion experiments conducted on relatively limited sectors of reefs could give some estimates of populations and biomass per kilometre of reef front but clearly would be inapplicable over wider areas of shelf with generalized cover of corals. None of the available parameter estimates is very securely based and, for example, is sufficiently divergent to have generated much uncertainty about the best management measures to adopt for the Tongan fishery (Prescott, 1990).

3.2

Conclusions

Spiny lobster catches in the tropical Indo-West Pacific are relatively small, but are a commercially important component of the catches of the small-scale fishers in the tropical Indo-West Pacific. The principal means of capture is by spearing but there is sufficient evidence of the vulnerability of P. penicillatus and P. longipes to traps to warrant further investigation.

96

Spiny Lobsters: Fisheries and Culture

Because of the relatively low volume and dispersed nature of landings, estimates of production in most countries are incomplete or non-existent and are probably gross underestimates in most cases. Few sustained attempts have been made to estimate the biological parameters regulating production. Consequently, apart from P. ornatus in the Torres Strait and Gulf of Papua (see references in Phillips et al., Chapter 1), no well-founded management plans are in place for any stock in the entire tropical Indo-West Pacific region.

References Berry, P.F. (1970) Mating behaviour, oviposition and fertilization in the spiny lobster, Panulirus homarus (Linnaeus). Invest. Rep. Oceanogr. Res. Inst., Durban, South Africa, 24, 16 pp. Berry, P.F. (1971) The spiny lobsters (Palinuridae) of the east coast of southern Africa: distribution and ecological notes. Invest. Rep. Oceanogr. Res. Inst., Durban, South Africa, 27, 23 pp. Bhatia, U. (1974) Distribution of spiny lobsters along the west coast of Thailand with observations on their fishing grounds. Phuket Mar. Biol. Ctr. Res. Bull., No. 5, 20 pp. Charbonnier, D. & Crosnier, A. (1961) Quelques donnees sur la peche des langoustes a Madagascar. Peche Marit., No. 994, 16±18. De Bruin, G.H.P. (1969) The ecology of spiny lobsters, Panulirus spp. of Ceylon waters. Bull. Fish Res. Stn. Ceylon, No. 20, 171±89. Ebert, .A. & Ford, R.F. (1986) Population ecology and fishery potential of the spiny lobster, Panulirus penicillatus at Enewetak Atoll, Marshall Islands. Bull. Mar. Sci., 38, 56±67. FAO (1998) Yearbook of fishery statistics. 1996 catches and landings. Food and Agriculture Organization of the United Nations, Rome (online database). Felfoldy-Ferguson, K. (1988) The collection and uses of inshore reef fisheries information to assess and monitor the shelf fisheries of the Kingdom of Tonga, using the ICLARM approach: summary of the first year's activities and results. South Pacific Commission Workshop on Pacific Inshore Fishery Resources. Noumea New Caledonia: March 1988. Background Paper No. 41, 13 pp. George, R.W. (1972) South Pacific islands rock lobster resources. FAO Rep. FI:RAS/69/102/9, 41 pp. Juinio, A.R. & Gomez, E.D. (1986) Spiny lobster fishery in eastern Samar, Philippines. In The First Asian Fisheries Forum. (Ed. by J.L. Maclean, L.B. Dizon & H.V. Hosillos), pp. 381±4. Asian Fisheries Society, Manila, Philippines. MacDonald, C. (1979) Management aspects of the biology of the spiny lobsters, Panulirus marginatus, P. penicillatus, P. versicolor and P. longipes femoristriga in Hawaii and the Western Pacific. Report to Western Pacific Regional Fishery Management Council, Univ. Hawaii. Acct. No. F-78±237-F-051-B-123, 126 pp. MacDonald, C.D. (1982) Catch composition and reproduction of the spiny lobster Panulirus versicolor at Palau. Trans. Am. Fish. Soc., 111, 694±9. Mohamed, K.H. & George, M.J. (1968) Results of tagging experiments on the Indian spiny lobster, Panulirus homarus ± movement and growth. Indian J. Fish., 15, 15±26. Munro, J.L. (1988) Growth and mortality rates and state of exploitation of spiny lobsters in Tonga. South Pacific Commission, Workshop on Pacific Inshore Fisheries Resources. Noumea New Caledonia: March 1988. Working paper No. 51, 34 pp. Mutagyera, W.B. (1975) A preliminary report on the spiny lobster fishery in Zanzibar. Afr. J. Trop. Hydrobiol. Fish., 4, 51±9

Fisheries for Spiny Lobsters in the Tropical Indo-West Pacific

97

Pitcher, R.C. (1993) Spiny lobster. In Nearshore Marine Resources of the South Pacific (Ed. by A. Wright & L. Hill), pp. 539±607. Institute of Pacific Studies, Suva, Fiji; Forum Fisheries Agency, Honiara, Solomon Islands & International Centre for Ocean Development, Canada. Prescott, J. (1980) Report on the South Pacific Commission Lobster Project in Solomon Islands. South Pacific Commission, Noumea, New Caledonia, 24 pp. Prescott, J. (1988) Tropical spiny lobster: an overview of their biology, the fisheries and the economics with particular reference to the double-spined rock lobster, P. penicillatus. South Pacific Commission, Workshop on Pacific Inshore Fishery Resources, Noumea, New Caledonia: March 1988. Working paper No. 18, 35 pp. Prescott, J. (1990) A survey of the lobster resources in the Ha'apai group, Kingdom of Tonga. South Pacific Forum Fisheries Agency, Rep. No. 90/93, 31 pp. Pyne, R.R. (1970) Tropical spiny lobsters Panulirus spp. of Papua and New Guinea. Search, 1, 248± 53. Rongmuangsart, S. & Luvira, O. (1973) Studies on the biology and population dynamics of the spiny lobster, Panulirus polyphagus (Herbst), of the West Coast of Thailand, with notes on experimental rearing of P. versicolor (Latrielle) in the laboratory. Phuket Marine Biological Center, Res. Bull. No. 2, 22 pp. Williams, A.B. (1988) Lobsters of the World. Osprey Books, New York, USA, 186 pp. Zann, L.P. (1984) A preliminary investigation of the biology and fisheries of the spiny lobsters (Palinuridae) in the Kingdom of Tonga. Institute of Marine Resources, University of the South Pacific Rep., 55 pp.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 4

The Lobster Fishery in the North-western Hawaiian Islands J.J. POLOVINA Honolulu Laboratory, Southwest Fisheries Science Center, National Marine Fisheries Service, NOAA, 2570 Dole Street, Honolulu, Hawaii 96822-2396, USA

4.1

Introduction

The North-western Hawaiian Islands (NWHI) are an isolated range of islands, islets, banks and reefs extending 1500 nautical miles north-west, from Nihoa Island to Kure Atoll (Fig. 4.1). Lobster concentrations in the NWHI were documented by research cruises in 1976 and commercial trapping had begun by 1977 (Uchida & Tagami, 1984). The fishery targets two species: the endemic spiny lobster Panulirus marginatus Quoy and Gaimard 1825 and the common slipper lobster Scyllarides squammosus Milne-Edwards 1837. Two other species ± the ridgeback slipper lobster S. haanii de Haan 1841 and the Chinese slipper lobster Parribacus antarcticus Lund 1793 ± are caught incidentally in low abundance. Since 1983, the lobster fleet has ranged from nine to 16 vessels (15±35 m long), each averaging three trips per year (Fig. 4.2). The vessels set about 800 traps per day and remain at sea for almost 2 months per trip. Landings and effort increased rapidly in the early 1980s to a maximum landing for spiny and slipper lobsters combined of about 2 million in 1985 with an effort of about 1 million trap-hauls (Fig. 4.3). However, by the late 1980s, as a result of the process of fishing down a previously unexploited population, combined spiny and slipper landings had dropped to about 1 million lobsters. In the early 1990s a change from open access to limited entry and harvest quota management, together with an environmental regime change which adversely impacted spiny lobster recruitment, has resulted in recent landings in the range of 200 000±300 000 lobsters (Fig. 4.3). The ex-vessel revenue of the fishery has ranged from about US $5±6 million in the late 1980s to US $1±2 million in the mid-1990s. For most of the 1980s and early 1990s the lobsters were landed and marketed as frozen tails, but beginning in 1997 a few boats explored landing and marketing live lobsters. Since 1988, 60±80% of the landings have been spiny lobster (Table 4.1). Fathoms Plus shellfish traps are used by all fishermen (Fig. 4.4). This trap is dome-shaped, single-chambered and made of moulded black polyethylene which measures 98  770  295 mm, with a mesh size of 45  45 mm (inside dimensions). Each trap has two entrance cones located on opposite sides. Each trap also has two escape vent panels each consisting of four circular vents, 67 mm in diameter, located on opposite sides to facilitate the escape of immature lobsters. The traps are typically baited with chopped mackerel (Scomber sp.), fished 98

The Lobster Fishery in the North-western Hawaiian Islands

Figure 4.1

99

The Hawaiian Archipelago, including the North-western Hawaiian Islands.

in strings of several hundred traps per string, and most frequently set in depths of 20±50 m.

Figure 4.2 A typical lobster vessel fishing in the North-western Hawaiian Islands.

100 Spiny Lobsters: Fisheries and Culture

Figure 4.3 Total lobster landings (millions of lobsters) and trapping effort (millions of traphauls) for the combined slipper and spiny lobster fishery in the North-western Hawaiian Islands, 1983±1997.

Figure 4.4 A lobster trap with an escape panel commonly used by the lobster fishery in the North-western Hawaiian Islands.

The Lobster Fishery in the North-western Hawaiian Islands

101

Table 4.1 Annual landings of spiny and slipper lobsters (thousands), trapping effort (thousand trap-hauls), CPUE (lobsters per trap-haul) and the percentage of spiny lobster in the landings, 1983±1990a Year

Spiny lobster

Slipper lobsterb

Total lobsters

Trapping effort

CPUE

Spiny lobster (%)

1983c 1984 1985 1986

158 677 1022 843

18 207 900 851

176 884 1902 1694

64 371 1041 1293

2.75 2.38 1.83 1.31

90 78 53 50

1987 1988 1989 1990

393 888 944 591

352 174 222 187

745 1062 1166 777

806 840 1069 1182

0.92 1.26 1.09 0.66

53 84 81 76

1991 1992 1993d 1994 1995

131 248 ± 85 34

35 163 ± 46 3

166 411 ± 131 37

295 685 ± 168 64

0.56 0.60 ± 0.79 0.58

79 60 ± 65 92

1996 1997

165 176

22 134

187 310

115 178

0.94 1.74

88 57

a Data were provided to the National Marine Fisheries Service as required by the Crustacean Fishery Management Plan of the Western Pacific Regional Fishery Management Council. b Slipper lobster landings for 1984±1987 are 72% of those reported, so they are comparable to landings after 1987 when a minimum size allowed the retention of about 72% of the catch. c April±December 1983. d Fishery closed.

4.2

Management

The NWHI lobster fishery has been managed under federal jurisdiction with a fishery management plan (FMP) administered by the Western Pacific Regional Fishery Management Council (WPRFMC) since 1983. The NWHI fishery is managed with a limited-entry system for a maximum of 15 vessels, an annual fleet harvest quota and a closed season from January to June to protect the spawning biomass before the summer spawning. An annual harvest quota is set for each region as 13% of the July estimated exploitable population (DiNardo & Wetherall, 1999). The constant harvest rate of 13% was selected based on a decision by managers that the corresponding annual fishing mortality have a probability of less than 0.10 of exceeding the fishing mortality, which results in a spawning potential ration of 20% (DiNardo & Wetherall, 1999). The region-wide quota is allocated geographically to prevent overfishing at the closest banks. There is no minimum size or prohibition on the retention of egg-bearing females. In fact, while all traps are required to have

102 Spiny Lobsters: Fisheries and Culture escape vents to reduce handling and release-induced mortality on immature lobsters, all lobsters which are caught are counted against the quota and must be landed. Finally, all vessels must submit logbooks recording daily catch and trapping effort. Currently, fishermen and managers are examining whether an individual quota would be an improvement over the current fleet quota.

4.3

Stock assessment

Stock assessment has used the annual catch of spiny and slipper lobsters and trapping effort data from the commercial logbooks since 1983 (Table 4.1). During 1983±1997, the proportion of spiny and slipper lobsters in the catches varied because of targeting by fishermen and variations in abundance. Trapping is a multispecies effort and logbooks do not specify when effort targets spiny or slipper lobster. Stock assessment of the lobster resource is hindered by the relatively short catch and effort time series, the inability to age lobsters and changes in management regulations. For example, the increase in catch per unit effort (CPUE) in 1996 and 1997 is primarily due to a management change eliminating a minimum size in favor of requiring the retention of all catch. However, the following population dynamics model has been used successfully since the early 1990s. The monthly total number of exploitable lobsters (Nt) is expressed as a function of the number of exploitable lobster in the previous month (Nt 1) adjusted for annual instantaneous natural mortality (m), monthly catch (Ct 1), and constant annual recruitment (R) as: Nt ˆ Nt 1 e

m=12

Ct

1

‡ R=12:

…4:1a†

The model-based estimate of Nt was then converted to a CPUE value by multiplying by the catchability (q): CPUEt ˆ qNt :

…4:1b†

Model-based parameters (m, q, R) were estimated using an iterative non-linear least squares method that minimizes the residual sums of squares between observed and estimated monthly CPUE. For several years the season harvest quota was set for the entire fishing ground, computed as 13% of the total number of exploitable lobsters (Nt) in the fishing ground, estimated from this model for the beginning of the fishing season. However, beginning in 1998 the harvest quota was determined separately for each of four regions in the fishing ground by application of the assessment model on a regional basis. Estimated regional exploitable population sizes were obtained and regional harvest quotas assigned as 13% of those numbers. The population dynamics model finds evidence of a 50% drop in mean annual recruitment after 1990, consistent with atmospheric and oceanographic data and NWHI ecosystem data indicating a regime shift in the late 1980s (Polovina et al., 1994, 1995; Polovina & Haight, in press).

The Lobster Fishery in the North-western Hawaiian Islands 4.4

103

Research

After the initial research cruises documenting lobster concentrations in the NWHI in 1976, research focused on the biology of the spiny lobster P. marginatus. Tagging studies at Kure Atoll and French Frigate Shoals estimated a von Bertalanffy growth curve for growth (in carapace length) to have a parameter k of 0.31/year with an asymptotic carapace length of 13.2 cm (MacDonald, 1984). Also obtained was a mean natural mortality estimate of 0.37/year, along with estimates for the ages at the onset of sexual maturity (2.7 years for males and 1.7 years for females; MacDonald, 1984). In 1998 over 3000 spiny lobsters were tagged at Necker Island as part of a study to update estimates of population parameters. Trapping surveys mapped the spatial distribution of P. marginatus in the NWHI and indicated that the highest catch rates ranged from depths of 55±73 m in the south-eastern portion of the NWHI to 19±54 m in the north-western portion of the Hawaiian Archipelago (Uchida & Tagami, 1984). Research conducted during 1984±1987 developed escape vents to reduce the catch and hence mortality of sublegal spiny lobster (<50 mm tail width) and sublegal slipper lobster (<56 mm tail width) without reducing legal catches. A circular vent design takes advantage of the differences in the morphology of spiny and slipper lobsters, allowing escape at different tail sizes for each species. Specifically, research found that traps equipped with two vent panels consisting of four 67 mm diameter circles placed at the bottom of the trap caught 83% and 93% fewer sublegal spiny and slipper lobsters than did non-vented control traps, without significantly reducing legal catches of either species (Everson et al., 1992). An estimated 2000 plastic traps are lost annually in the NWHI. Concern has been raised that lobsters entering those lost traps may be unable to exit and therefore die. Recent field and tank studies have investigated whether lobsters can escape unbaited lobster traps. The results indicate that lobsters using the traps for shelter are able to exit, and no mortality due to the retention of slipper or spiny lobster in traps was observed (Parrish & Kazama, 1992). Recently, the issues of spiny lobster larval metapopulation dynamics have been investigated using remote sensing. Specifically, satellite altimetry from the TOPEX/ Poseidon satellite has been used to compute geostrophic currents every 10 days around the Hawaiian Islands since 1993. An advection±diffusion model, driven by the geostrophic currents estimated from TOPEX/Poseidon data, is used to simulate the movement of lobster larvae over their 12-month pelagic period (Polovina et al., 1999). The simulations indicate that banks located in different positions in the archipelago differ substantially in both the proportion of larvae that they retain from resident spawners and the proportion of larvae that they receive from other banks (Polovina et al., 1999). One economic study (Clarke & Pooley, 1988) has examined the return on investment as a function of the vessel size. The most profitable vessels in the fleet are the midsized vessels. These vessels are 20±30 m long, have five to nine crew members

104 Spiny Lobsters: Fisheries and Culture and are able to set 600±820 traps per day. Larger vessels face cost constraints, while smaller vessels face operational problems.

References Clarke, R.P. & Pooley, S.G. (1988) An economic analysis of lobster fishing vessel performance in the Northwestern Hawaiian Islands. U.S. Dept. Commer., NOAA Tech. Memo. NMFSSWFC-106, 45 pp. Dinardo, G.T. & Wetherall, J.A. (1999) Accounting for uncertainty in the development of harvest strategies for the Northwestern Hawaiian Islands lobster trap fishery. ICES J. Mar. Sci., 56, 943±51. Everson, A.R., Skillman, R.A. & Polovina, J.J. (1992) Evaluation of rectangular and circular escape vents in the Northwestern Hawaiian Islands lobster fishery. N. Am. J. Fish. Manage., 12, 161± 71. MacDonald, C.D. (1984) Studies on recruitment in the Hawaiian spiny lobster, P. marginatus. In Proc. Second Symp. Resource Investigations in the Northwestern Hawaiian Islands, May 25±27, 1983, Honolulu, Vol. 1 (Ed. by R.W. Grigg & K.Y. Tanoue), pp. 199±220. University of Hawaii, HI, USA. Parrish, F.A. & Kazama, T.K. (1992) Evaluation of ghost fishing in the Hawaiian lobster fishery. Fish. Bull., U.S., 90, 720±5. Polovina, J.J. & Haight, W. (1999) Climate variation, ecosystem dynamics, and fisheries management in the Northwestern Hawaiian Islands. Proc. International Symp. on Ecosystem Considerations in Fisheries Management. Alaska Sea Grant College, AK-SG-99-01, 23±30. Polovina, J.J., Haight, W.R., Moffitt, R.B. & Parrish, F.A. (1995) The role of benthic habitat, oceanography, and fishing on the population dynamics of the spiny lobster, Panulirus marginatus, in the Hawaiian Archipelago. Crustaceana, 68, 203±12. Polovina, J.J., Kleiber, P. & Kobayashi, D. (1999) Application of TOPEX/Poseidon satellite altimetry to simulate transport dynamics of larvae of the spiny lobster, Panulirus marginatus, in the Northwestern Hawaiian Islands, 1993±96. Fish. Bull., U.S., 97, 132±43. Polovina, J.J., Mitchum, G.T. Graham, N.E., Craig, M.P., DeMartini, E.E. & Flint, E.N. (1994) Physical and biological consequences of a climate event in the central North Pacific. Fish. Oceanog., 3, 15±21. Uchida, R.N. & Tagami, D.T. (1984) Biology, distribution, population structure, and preexploitation abundance of spiny lobster, Panulirus marginatus (Quoy and Gaimard 1825), in the Northwestern Hawaiian Islands. In Proc. Second Symp. Resource Investigations in the Northwestern Hawaiian Islands, May 25±27, 1983, Honolulu, Vol. 1 (Ed. by R.W. Grigg & K.Y. Tanoue), pp. 157±97. University of Hawaii, HI, USA.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 5

The Commercial Fisheries for Jasus and Palinurus Species in the South-east Atlantic and South-west Indian Oceans D.E. POLLOCK, A.C. COCKCROFT, J.C. GROENEVELD and D.S. SCHOEMAN Marine and Coastal Management, Department of Environmental Affairs and Tourism, P. Bag X2, Rogge Bay 8012, South Africa

5.1

Introduction

Two closely related Jasus species occur in the South-east Atlantic region, the continental species J. lalandii and the insular species J. tristani. Jasus lalandii is widespread on the southern African west coast, while J. tristani is endemic to areas surrounding the Islands Tristan da Cunha and Gough, and to the Vema Seamount in the Cape Basin (Fig. 5.1). Similarly, two closely related Palinurus species occur in the South-west Indian region, P. gilchristi along the South African south coast, and P. delagoae off the south-eastern coasts of Africa and Madagascar (Fig. 5.1). Both are considered deep-water species, inhabiting waters deeper than 50 m. However, while the distribution of P. gilchristi is limited by the outer edge of the continental shelf, P. delagoae extends its distribution beyond the shelf-break, to depths exceeding 600 m. The only species to co-occur are J. lalandii and P. gilchristi; their distributions overlap at the southern tip of Africa (Fig. 5.1). Nevertheless, the fisheries for each of the four species are discrete. They are, however, not uncomplicated. Jasus lalandii and P. delagoae are straddling stocks shared with South Africa's north-western and north-eastern coastal neighbours, respectively (Fig. 5.1), but there is little co-operative management in either instance. The management of P. delagoae is further complicated because not only is this species the target of directed trap fishing in Mozambique, but it also forms an important component of a multispecies crustacean trawl fishery in both Mozambican and South African waters, the former by a multinational fleet. Conversely, P. gilchristi is confined to areas within the South African exclusive economic zone (EEZ), where foreign vessels are prohibited. Although this is a directed fishery, with restricted local participation, issues surrounding fishing behaviour have thus far confounded attempts at management. Commercial exploitation of J. tristani is complicated by its distribution across both international waters, where uncontrolled fishing has depleted stocks sustainably, and areas under British dependency, where it is fished by islanders and by a South African-based company. 105

106 Spiny Lobsters: Fisheries and Culture

Fig. 5.1 Spatial distribution of fishing grounds for the rock lobster species under consideration.

Pollock (1986) provided a comprehensive description of the fishery for and biology of J. lalandii in South Africa, and later both supplemented this and included information on J. tristani and P. gilchristi (Pollock, 1994). Wherever possible, duplication of details will be avoided here; the following sections serve to update information on J. lalandii, J. tristani and P. gilchristi, and to provide a concise description of the fisheries for P. delagoae. 5.2 The southern African fishery for Jasus lalandii: the role of the environment

The west coast rock lobster Jasus lalandii occurs in commercially exploitable densities from about 25 S in Namibia to approximately Cape Hangklip (34 230 S, 18 000 E), to the east of the Cape Peninsula, South Africa (Fig. 5.1), a distance of some 1055 km. Although aggregations of J. lalandii have been located at depths exceeding 400 m off Cape Point (D.E. Pollock, Marine and Coastal Management, unpubl. data), the majority of commercial catches is made in shallower water. Over the southern grounds, fishing is concentrated at depths between 5 and 100 m, while over the central and northern grounds, the maximum fishing depth decreases progressively to about 30 m. The South African and Namibian fisheries for J. lalandii are managed largely independently of one another. However, yields from the entire Namibian fishery and from the northern component (Namaqualand) of the South African fishery have declined dramatically, and more or less simultaneously, since the 1950s (Pollock, 1994). Owing to the collapse of these northern sectors, the overall annual yield from

Fisheries in the South-east Atlantic and South-west Indian Oceans

107

the resource declined from over 16 000 t prior to 1955 to less than 5000 t after the 1960s. Unfortunately, a series of changes to minimum size limits during the period of rapid decline has complicated interpretation of events (Pollock, 1987; Pollock & Shannon, 1987). Nevertheless, it is becoming increasingly clear that the J. lalandii resource could be more usefully divided using physical oceanographic characteristics than political boundaries. The nearshore shelf waters along the approximately 740 km of coast stretching south from central Namibia into Namaqualand are characterized by regular periods of oxygen depletion (Pollock & Beyers, 1981; Pollock, 1982; Beyers & Wilke, 1990; Grobler & Noli-Peard, 1997). The responses of J. lalandii populations to low oxygen levels are well documented, and include decreasing commercial catch rates (Newman & Pollock, 1971; Bailey et al., 1985; Beyers & Wilke, 1990), reduced growth rates (Pollock & Beyers, 1981; Pollock & Shannon, 1987; Beyers et al., 1994), smaller size at sexual maturity and reduced fecundity (Beyers & Goosen, 1987), decreased food consumption rates and higher mortality rates at moulting (Beyers et al., 1994), mass mortalities (Newman & Pollock, 1974; Pollock & Bailey, 1986; Matthews & Pitcher, 1996; Cockcroft et al., 2000) and, in particular, restricted depth distribution (Newman & Pollock, 1971; Bailey et al., 1985; Pollock & Shannon, 1987; Beyers & Wilke, 1990). Along this otherwise highly productive coastline, the relatively low local rates of rock lobster production are probably a direct result of the restriction of rock lobster to shallow waters (often <15 m depth) for much of the year (Pollock, 1987; Pollock & Shannon, 1987). However, there is anecdotal evidence that this was not always the case (Beyers & Wilke, 1990). Prior to the 1960s, fishermen reported making good catches in depths of up to 55 m off both the Namibian and Namaqualand coasts. There are also some suggestions that lobster sizes at maturity were larger then than nowadays. If correct, these assertions would suggest both that the distribution patterns and growth rates of rock lobster changed at about the same time as the catches declined, and that they have not since recovered. This hypothesis could be simply explained if an increase in the frequency of oxygen-depleted bottom waters further offshore forced the rock lobster population to occupy an increasingly restricted, shallow-water habitat. Density-dependent effects on growth and survival (Pollock, 1987; Pollock & Shannon, 1987), together with decreased catchability in the high wave-energy, shallow-water environment, could then account for the decreased fishery yields. The potentially large impact that changes in oxygen levels may have had on rock lobster stocks in the northern and central Benguela upwelling system (as well as possible related impacts on demersal and pelagic fish populations), have identified this phenomenon as a research priority. Ongoing investigations have been designed to seek an explanation of its origin and its apparent variability over time. Although conclusive results have yet to be obtained, current understanding is that a large increase in primary productivity must have taken place after the 1950s. This may have intensified the production of oxygen-depleted bottom waters in the diatom-rich coastal waters of northern Namibia (Pollock & Shannon, 1987), which could, in

108 Spiny Lobsters: Fisheries and Culture turn, have been spread southwards along the Namibian and Namaqualand coasts under the influence of the well-documented poleward undercurrent (De Dekker, 1970; Nelson, 1989). Preliminary analyses of the deposition patterns of large, chain-forming diatom species in coastal sediments within the so-called diatomaceous mud belt, between 19 S and 25 S, off the Namib Desert coast, point towards loci of nutrient enrichment unrelated to simple wind-induced upwelling (D.E. Pollock, Marine and Coastal Management, unpubl. data). These nearshore centres of nutrient enrichment are located adjacent to the points where major underground river systems meet the coast (Fig. 5.2), hinting that seepage of subterranean groundwaters from the ephemeral rivers draining the western escarpment may be the key to the enhanced productivity of the region. This idea is supported by chemical analyses of subterranean

Fig. 5.2 Distribution of ephemeral river systems in northern Namibia, the poleward undercurrent, and the lobster grounds most affected by oxygen-depleted subsurface waters (hatched area).

Fisheries in the South-east Atlantic and South-west Indian Oceans

109

groundwaters, which display exceedingly high levels of dissolved silicate (Marine and Coastal Management, unpubl. data), a key nutrient for diatom production (Officer & Ryther, 1980; Dugdale, 1983). Correspondingly, coastal upwelled waters within the 19±25 S region have been found to contain unusually high concentrations of dissolved silicate (Bailey, 1979; Boyd, 1983). Rainfall patterns in adjacent river catchments illustrate a marked change in the rainfall regime, which began during the 1960s (Fig. 5.3). Rainfall increased in all catchments during the late 1960s and throughout the 1970s, but decreased again during the 1980s and 1990s. This implies that a nutrient-driven change in ecosystem productivity may have commenced during the late 1960s. Amongst the consequences, the increased production of oxygen-depleted bottom waters in the region 19±25 S, the coincident collapse of the west coast pilchard stock, and its replacement by anchovies and pelagic gobies (Crawford et al., 1985) appear to have been the most significant. The lack of recovery, to date, of the Namibian and Namaqualand rock lobster stocks gives credence to the idea that the system has not reverted to its earlier, apparently less productive phase. Silicate recycling over the siliceous mudbelt in the region 19±25 S may currently be maintaining the system in a hypertrophic mode, with persistently high levels of diatom production and decay, and a southward advection of oxygen-depleted bottom waters. The fishing grounds to the south of Namaqualand continue to yield the highest catches, but even here, marked interannual variations in lobster growth rates have taken place, especially after 1989 (Melville-Smith et al., 1995; Cruywagen, 1997; Pollock et al., 1997). These events and their effects on fishery yields and on management strategies are described in the following sections.

Fig. 5.3 Example of temporal rainfall patterns in northern Namibia; annual data from Windhoek (see Fig. 5.2) expressed as deviations from the long-term average.

110 Spiny Lobsters: Fisheries and Culture 5.3

The Namibian fishery for Jasus lalandii

Because the history of the Namibian J. lalandii commercial fishery has been thoroughly reviewed (Matthews & Smit, 1978; Beyers & Wilke, 1990; Tomalin, 1993), this aspect will be only briefly outlined here. The exploitation of this resource in Namibia commenced in the early 1920s and annual catches remained relatively high (around 9000 t) until the mid-1960s. By 1967, the fishery was on the verge of collapse, and only the abolition of the minimum size limit during 1968 and 1969 could maintain landings at levels high enough to support the industry. In 1970, effort was drastically curtailed and a minimum size limit reintroduced. Subsequently, annual total allowable catches (TACs) were reduced in a stepwise fashion, stabilizing at 2200 t from 1979 to 1987. Despite these measures, the industry remained unable to land the TAC for two decades. Eventually, during the 1989/90 and 1990/91 seasons, landings and catch rates declined sufficiently to result in the reduction of the 1991/92 TAC to 100 t, a level which finally restricted catches (Grobler & Noli-Peard, 1997). The 1991/92 TAC heralded a management strategy aimed at rebuilding the resource by setting conservative TACs. This policy was continued throughout the 1990s (Grobler & Noli-Peard, 1997), with TAC levels increasing very slowly during this period, reaching 300 tons in 1998/99 (Table 5.1). As a result of the low TACs, most Namibian rock lobster fishing is currently conducted in the immediate vicinity of LuÈderitz (Figure 5.1), and all landings are offloaded at this desert port, a practice Table 5.1 Total allowable catches and commercial catches (t) from the fisheries for Jasus lalandii and Jasus tristani Namibiaa

South Africa

The Tristan/Gough Island groupb

Season

TAC

Landings

TAC

Landings

TAC

Landings

1989/90 1990/91

1800 1100

589 329

3900 3790

3491 3018

No TAC No TAC

450 428

1991/92 1992/93 1993/94 1994/95

100 300c 130 230

100 200 133 222

2200 2200 2200 2000

2430 2176 2199 1962

No TAC 342 338 352

368 364 304 333

1995/96 1996/97 1997/98 1998/99

250 260 260 300

251 257 260 302

1520 1675 1920 1909

1517 1679 1917

342 405 323 323

327 371 311

a

C.A.F. Grobler, Ministry of Fisheries and Marine Resources, Namibia (pers. comm.). J. Glass, Head of Natural Resources, Tristan da Cunha (pers. comm.). c Although a further 100 t were added to the original 200-t allocation, no attempt was made to land this addition owing to a delay in the season opening. b

Fisheries in the South-east Atlantic and South-west Indian Oceans

111

that simplifies management to some extent. With only one exception, the annual TAC has been caught in full since the introduction of the conservative TACs. Since Namibia attained independence from South Africa in 1990, research has focused on the influence of environmental factors (such as wind stress, swell height and dissolved oxygen content of bottom waters) on the seasonal trends in lobster abundance, size distribution and catch rates. Results from commercial and research sampling since the mid-1990s indicate improved recruitment and increased, although variable, catch per unit effort (CPUE). The conservative management regime therefore seems to be having the desired effect. Nevertheless, management of this resource will have to remain conservative over an extended period before a substantial recovery of the Namibian J. lalandii stock can be expected (Grobler & Noli-Peard, 1997).

5.4

The South African fishery for Jasus lalandii

In the most recent review on the topic, Pollock (1994) noted that the stability experienced by the South African J. lalandii commercial fishery during the 1980s ended in 1989. Previously, 3500±4000 t of rock lobster were landed annually, but in the 1989/90 season, only 3491 t of the allotted 3900 t TAC could be caught (Table 5.1). The situation deteriorated further during the 1990/91 season, when only 3018 t (including 270 t from outside the traditional fishing areas) were landed out of a reduced TAC of 3790 t. These poor catches are believed to have been caused by a decrease in recruitment to the harvestable biomass (that part of the resource larger than the minimum legal size) in direct response to a dramatic reduction in somatic growth rates (Pollock, 1994; Cockcroft, 1997). Average growth rates over five fishing grounds during the period 1989±1992 were about 50% lower than those recorded in 1987 and 1988 (Table 5.2), years believed to be representative of `normal' growth (Goosen & Cockcroft, 1995; Melville-Smith et al., 1995). The low growth rates recorded during this period were heavily influenced by the fact that large numbers of rock lobster failed to increase in size during their annual moult; some even becoming smaller (Cockcroft & Goosen, 1995). The causes of this slow growth are not yet clearly understood. However, its widespread nature was indicative of the role of a largescale environmental perturbation. This prompted Pollock et al. (1997) to postulate that the anomalous El NinÄo years of 1990±1993 may have been influential in changes in the productivity of the southern Benguela Current. Because the decline in growth rate had a major effect on the productivity of the rock lobster resource, it has also had significant repercussions for its management. In response to the continued poor catches during the early part of the 1991/92 season (Table 5.1), the minimum legal size was temporarily reduced from 89 to 75 mm carapace length (CL) for the remainder of the season. Although the minimum legal size was adjusted to 80 mm carapace length (CL) for the 1992/93 season, it was again

112 Spiny Lobsters: Fisheries and Culture Table 5.2 Mean annual moult increments (mm CL) of male Jasus lalandii at five fishing grounds along the South African coast Season

Cape Peninsula

Hout Bay

Dassen Island

Elands Bay

Oubeep Bay

1987/88 1988/89 1989/90

2.2 (88) 1.8 (122) 2.2 (96)

5.0 (41) 3.6 (7) 3.4 (10)

4.3 (47) 4.6 (54) 3.2 (54)

4.8 (9) 3.6 (33) 2.5 (13)

1.5 (72) 1.7 (41) 1.1 (16)

1990/91 1991/92 1992/93 1993/94 1994/95

1.3 1.1 1.1 0.8 1.4

1.0 2.0 1.7 1.4 3.2

1.5 1.0 1.1 2.5 2.5

0.8 3.2 2.1 ± 2.2

0.5 0.4 0.9 1.1 0.2

1995/96 1996/97 1997/98

1.5 (89) 1.5 (54) 1.4 (111)

(34) (87) (295) (74) (53)

(3) (9) (170) (48) (130)

3.3 (187) 3.2 (116) 2.2 (145)

(36) (40) (92) (53) (43)

3.7 (46) 3.7 (21) 3.0 (27)

(13) (80) (139) (94)

1.2 (45) 3.9 (21) 2.1 (14)

(66) (31) (57) (147) (47)

1.1 (66) 1.6 (54) 1.4 (42)

Number of observations (tag returns) is given in parentheses. Increments apply to specimens in the 80±89 mm CL size range only.

reduced to 75 mm CL for the 1993/94 season, and has remained as such since then. During the same period, the annual TAC was rapidly decreased, falling from 3790 t in 1990/91 to 1500 t in 1995/96 (Table 5.1). There has subsequently been a modest improvement in the growth rate, resulting in a gradual increase in TAC to just over 1900 t for the 1998/99 season. The slow growth phenomenon has also been an important catalyst for several other developments during the 1991/92±1998/99 review period. Of particular importance are the design and implementation of an annual fishery independent monitoring survey (FIMS) and the increased prominence of mathematical modelling in the provision of management advice. The FIMS was introduced at the beginning of the 1992/93 season and was principally designed to monitor the possible effects on the resource of changes in the size limit. Based on a stratified random sampling procedure, this trap survey simply provides annual indices of population structure and of relative abundance of rock lobster populations inhabiting those grounds fished commercially using traps. The FIMS has superseded its initial function and now represents an indispensable source of information regarding commercially fished rock lobster populations. Its value lies in the fact that the FIMS is independent of the operational idiosyncrasies of the commercial fishery, and hence provides an alternative to commercial CPUE for the interpretation of population trends. Mathematical modelling was introduced as a tool for the assessment of the South African J. lalandii resource in the late 1980s and rapidly led to the development of a size-based model (Bergh & Johnston, 1992). This allowed the investigation of the predicted temporal trends in various parameters thought to influence population

Fisheries in the South-east Atlantic and South-west Indian Oceans

113

dynamics. Such assessments suggest that the resource is heavily depleted, with the harvestable biomass (biomass of lobsters > 75 mm CL) at about 5% of its preexploitation level, and spawning biomass (females > 65 mm CL) at some 20% of its believed pristine level. Of major concern is that the decrease in spawning biomass might be associated with a decline in recruitment, and hence future sustainable yields. Model results tend to confirm this fear, suggesting that recruitment during recent decades has been substantially depressed in comparison with the average for the pristine stock, presumably as a result of the smaller parent population. This implies that the drop in biomass since the mid-1980s may have resulted in a further decline in recruitment. To compensate for this, scientific consensus stipulated that any medium-term strategy for the utilization of J. lalandii should incorporate a stock rebuilding strategy. The culmination of the extensive modelling conducted during the mid-1990s was the development of an operational management procedure (OMP). The OMP is a standardized procedure for incorporating and analysing data to be used when setting annual TACs. Revolving around a relatively simple mathematical formula, the OMP requires as input the previous year's TAC and indices of commercial CPUE, FIMS CPUE and somatic growth rate. Following comprehensive robustness tests and consultation with both the industry and other role players, this procedure was accepted and implemented for the 1997/98 assessment. The OMP fulfils many of the precautionary principle guidelines (Cockcroft & Payne, 1999) and in its aims includes a 20% increase in resource biomass by the year 2006, thereby satisfying the need for stock rebuilding. The management problems caused by low growth were compounded during the review period by a series of rock lobster mass mortalities resulting from localized strandings along the South African west coast. These events were all associated with the decay of intense phytoplankton blooms and ranged in magnitude from a 60-t stranding in 1994 (Matthews & Pitcher, 1996) to a 2000-t stranding over a protracted period in April and May 1997. The latter was the worst rock lobster mortality ever recorded in South Africa (Cockcroft et al., 2000) and was followed by a further 200-t stranding at the same location in April, 1999 (Marine and Coastal Management, unpubl. data). Notwithstanding the previous discussion, the recent event that has had the most profound ramifications both for the rock lobster industry and for management fora, has been the implementation of a new fisheries policy for South Africa, the Marine Living Resources Act of 1998. This Act aims to maintain sustainability and industrial stability, while introducing a far greater level of equity than was previously apparent (Cockcroft & Payne, 1999). Although it is too early to evaluate the full impact of these changes, ongoing monitoring programmes have been instituted for this purpose.

114 Spiny Lobsters: Fisheries and Culture 5.5

The South Atlantic Fishery for Jasus tristani

Jasus tristani is endemic to the Vema Seamount and to the isolated mid-ocean islands of Gough, Tristan da Cunha, Nightingale and Inaccessible in the South-east Atlantic (Fig. 5.1). While the small resource at the Vema Seamount was rapidly depleted after the inception of the fishery there in the early 1960s (Pollock, 1994), catches from the other populations remain substantial. Although British authorities provide management advice, the Islands are largely self-sufficient and depend heavily on revenue generated by the rock lobster fishery. In his most recent review of the fishery for J. tristani, Pollock (1994) suggested that this resource could sustain annual catches of approximately 450 t, given the TAC regulations introduced during 1991, the minimum legal size of 70 mm CL and restrictions on gear. However, since that time, the TAC has infrequently been landed in full and catches have declined somewhat, reaching 311 t in the 1997/98 season (Table 5.1). Nevertheless, this does not necessarily reflect a decline in population strength; the TACs have stabilized at about 323 t and the size-composition data have not recently displayed the marked diminution evident during the early phases of the fishery (Pollock, 1994). Instead, the influence of weather patterns on fishing behaviour and the change to a new concession holder in 1997, with a concomitant modification of the fishing season, have combined to confound the conventional indicators of fishing performance. The perception of scientists involved with research on this resource is that stocks are gradually recovering (James Glass, Head of Natural Resources, Tristan da Cunha, pers. comm.).

5.6

The South African trap-fishery for Palinurus gilchristi

Palinurus gilchristi is endemic to the southern coast of South Africa (Fig. 5.1), where it occurs on rocky substrata inshore of the shelf break between Cape Point (18 E) and East London (28 E). Locally known as the south coast rock lobster, it is found in commercial densities along the coast and up to 250 km offshore on the Agulhas Bank. It is a deep-water species and is fished between depths of 50 and 200 m. Females generally carry eggs during the austral winter (June±October), when the bottom water temperature is somewhat warmer than it is in summer (Groeneveld & Rossouw, 1995). After the eggs hatch in spring (October±November), the majority of both male and female rock lobster undergo their annual moult (November± February). However, the frequency of moulting is size dependent, and small specimens (<80 mm CL) may moult more often than once a year (Groeneveld, 1997). Conversely, large females may occasionally forgo their annual moult, thereby extending their breeding period and providing an opportunity to produce a second batch of eggs between March and November. This comparatively poor temporal definition of reproductive and spawning seasons precludes the use of closed seasons as a management measure. Fishing is therefore allowed to proceed all year round.

Fisheries in the South-east Atlantic and South-west Indian Oceans

115

Tagging studies have shown P. gilchristi to be a long-lived (>20 years) and relatively slow-growing species (Groeneveld, 1997). Growth rates are faster on the western fishing grounds than on fishing grounds east of 27 E, a pattern mirrored by both the overall average size and the average size of female rock lobster at sexual maturity (Table 5.3). These trends are thought to be caused by a gradient in competition for limited resources, which results from the higher rock lobster abundance in the east, coupled with the restricted space available on the narrower continental shelf in that area. Commercial exploitation of P. gilchristi commenced in 1974 and expanded rapidly during the following 2 years. With numerous local and foreign fishing vessels converging on the newly discovered fishing grounds, catches had escalated to 2000 t by 1975 (Pollock & Augustyn, 1982). The subsequent recognition of P. gilchristi as a sedentary species of the continental shelf, belonging to South Africa alone, forced the withdrawal of foreign fishing vessels from the South African EEZ in 1976. Many of the remaining local fishing vessels were later forced to withdraw from the fishery when catches declined suddenly to 260 t in 1979/80. The resulting period of reduced effort allowed the resource (and catches) to recover somewhat (Fig. 5.4). Although the initial phases of the fishery were regulated only by limiting the number of traps permitted per vessel, an annual TAC was eventually introduced as a management tool in 1984 and trap limitations were abolished in 1988. Being based primarily on the recent performance of the fishery, the TAC remained stable at approximately 1025 t per year until the 1993/94 fishing season. During 1994, a more rigorous procedure was developed for the assessment of the resource. This used a Bayesian approach to fit a surplus production model to Table 5.3 Size at sexual maturity (mm CL), average size (mm CL) and growth parameters for Palinurus gilchristi on the western (Agulhas Bank, St Francis Bay and Port Elizabeth) and eastern (Port Alfred) fishing grounds

Size at 50% maturity: Presence of ovigerous setae

Western grounds

Eastern grounds

Male

Male

Female

Source

Female

±

65

±

59

±

71

±

62

Groeneveld & Melville-Smith (1995)

Presence of eggs Average CL (mm): 1978±1980 1988±1992

84.3 ±

82.9 75.3

69.5 ±

67.5 69.4

Pollock & Augustyn (1982) Groeneveld & Roussouw (1995)

Growth parameters: L1 (mm)

111.2

96.1

95.8

78.5

Groeneveld (1997)

K/year

0.092

0.129

0.050

0.065

Groeneveld (1997)

116 Spiny Lobsters: Fisheries and Culture

Fig. 5.4 Trends in catch and relative indices of effort and CPUE from the Palinurus gilchristi fishery (effort and CPUE were normalized from set hours and kg/trap, respectively).

commercial catch and effort data, growth parameters from a long-term tagging programme and catch-at-size information. Both CPUE trends and the surplus production model indicated a continuous decline in resource biomass since the 1989/ 90 fishing season (Fig. 5.4). In response, a programme of phased TAC reductions was initiated in 1994/95, resulting in a TAC for the 1997/98 season of 865 t. Unfortunately, these reductions failed to impact on the trend of declining CPUE, which now stands at 50% of its value in 1989/90 (Fig. 5.4). Although CPUE is often used directly as an index of relative abundance, it is possible that the relationship between these variables may be obscured by changes in fishing techniques. In 1974, fishing gear comprised individually buoyed traps deployed by fairly small vessels, which could remain at sea for limited periods. The subsequent evolution of a long-line system (which employs up to 200 plastic traps attached to each of several bottom lines), the introduction of larger vessels (up to 60 m in length), the deployment of increasing numbers of traps for longer periods (Fig. 5.4), and the improvement in navigational equipment have substantially increased the efficiency of fishing operations. As a result, although the mass of rock lobster landed per trap (CPUE) may have decreased, the total catch is made more cheaply. This may, at least in part, explain the continual decline in CPUE. To investigate this possibility, an experimental trap-reduction programme was designed and implemented for the 1998/99 commercial season. The programme is pivotal to the fishery; should results be negative, further reductions in the TAC will be necessary.

Fisheries in the South-east Atlantic and South-west Indian Oceans

117

The trap and trawl fisheries for Palinurus delagoae off South Africa and Mozambique

5.7

The distribution of P. delagoae (Fig. 5.1) stretches southwards along the eastern African coast from northern Mozambique (17 S) to southern KwaZulu-Natal (32 S), South Africa, including the south-eastern coast of Madagascar between these latitudes (Holthuis, 1991; Cockcroft et al., 1995). Like P. gilchristi, P. delagoae occurs in a temperate (12 C), deep-water (100±600 m) environment, and is slow growing (K = 0.059 0.076/year; L1 = 155 ± 165 mm CL) and long lived (M = 0.09 ± 0.15/year), where K and L1 are parameters of the Von Botalouffy equation, and M is the instantaneous rate of natural mortality (Groeneveld, in press). The population is spatially segregated according to size, with small specimens (<70 mm CL) occurring at depths in excess of 350 m and the remainder of the population distributed shoreward to the 100 m isobath (Cockcroft et al., 1995). This implies that post-larvae recruit at considerable depth before migrating slowly inshore as they grow and mature. Because of its distribution across a range of substrates, including rock and organically rich mud mixed with coral and sand (Berry, 1971; Berry & Plante, 1973), P. delagoae is susceptible to both trawl and trap fishing. Palinurus delagoae has been targeted by trawlers in both South African and Mozambican waters since the early 1960s (Berry, 1972; Palha de Sousa, 1992). Although South African vessels fish in Mozambican waters alongside a multinational fleet, no foreign vessels participate in the South African fishery. Catches during the 1960s are largely undocumented, but it is known that a single South African company landed 110 t of P. delagoae in 1965. After 1969, trawlers stopped targeting rock lobsters alone, thereby allowing the industry to evolve into a mixed crustacean trawl fishery, which currently lands rock lobster, prawns (Haliporoides triarthrus and Aristaeomorpha foliaceae), langoustines (Metanephrops mozambicus and Nephropsis stewartii), and red crabs (Chaceon macphersoni). This has the advantage that participants in the fishery are not limited by the availability of any one species, but may instead optimize their catch by trawling on different substrates and at selected depths in order to land a desirable mixture of species (Groeneveld & Melville-Smith, 1995). This fishery has yielded between 10 and 60 t of P. delagoae from South African waters each year between 1985 and 1998. Few reliable records are available from the Mozambican or Madagascan fisheries. Since 1980, a directed trap fishery has supplemented the P. delagoae trawl fishery in Mozambican waters (Palha de Sousa, 1992). Although 200±300 t were initially landed each year, annual catches had declined to 81 t by 1997 (Anon., 1998). The initial success of this fishery prompted the development in 1994 of a trapping experiment in South African waters to investigate the local potential of a P. delagoae trap fishery (Groeneveld & Cockcroft, 1997). As anticipated, large catches of P. delagoae (89.5 t) were made in the first year of trapping, with a substantial bycatch (30 t) of the slipper lobster Scyllarides elisabethae (Groeneveld et al., 1995).

118 Spiny Lobsters: Fisheries and Culture However, within 4 years, catches of P. delagoae had declined to 7.4 t, and the CPUE had similarly fallen by 75%. The depth-dependent segregation of the P. delagoae resource, in combination with operational limitations of the respective gear types, contributed to the failure of the trapping experiment. High-profile reef is not conducive to trawling. Therefore, in order to avoid such substrates, and to concentrate on the most valuable mixture of crustacean species, most trawling is conducted at depths exceeding 350 m. This results in catches composed primarily of immature and small adult (<80 mm CL) rock lobster (Groeneveld & Melville-Smith, 1995). By contrast, the influence of currents on buoy lines precludes trapping in water deeper than 450 m, which results in catches over a wider range of sizes, including large adults. Exacerbated by the slow somatic growth rate, the selection by trawls of smaller rock lobster reduces the rate of recruitment to the adult stock, thereby increasing its vulnerability to trap fishing. The declines in both catches and catch rates bear witness to the fact that the combined impact of these gear types is not sustainable in South African waters. Based on these results, the experiment was terminated in 1997, thereby suspending P. delagoae trapping in South African waters. Nevertheless, the trawl fishery continues and is managed effectively by limiting the number of vessels permitted to fish on the deep-water fishing grounds.

References Anon. (1998) Fishing Industry Handbook: South Africa, Namibia and Mozambique (Ed. by M. Stuttaford) Marine Information, Stellenbosch, South Africa, 438 pp. Bailey, G.W. (1979) Physical and chemical aspects of the Benguela Current in the LuÈderitz region. M.Sc. dissertation, University of Cape Town, South Africa, 225 pp. Bailey, G.W., Beyers, C.J.d.B. & Lipschitz, S.R. (1985) Seasonal variation of oxygen deficiency in waters off southern South West Africa in 1975 and 1976 and its relation to the catchability and distribution of the Cape rock lobster Jasus lalandii. S. Afr. J. Mar. Sci., 3, 197±214. Bergh, M.O. & Johnston, S.J. (1992) A size-structured model for renewable resource management, with application to resources of rock lobster in the South-east Atlantic. S. Afr. J. Mar. Sci., 12, 1005±16. Berry, P.F. (1971) The spiny lobsters (Palinuridae) of the east coast of southern Africa. Invest. Rep. Oceanogr. Res. Inst. S. Afr., 27, 1±23. Berry, P.F. (1972) Observations on the fishery for Palinurus delagoae. Oceanographic Research Institute, Durban, South Africa, unpublished report, 5pp. Berry, P.F. & Plante, R. (1973) Revision of the spiny lobster genus Palinurus in the South-west Indian Ocean. Trans. R. Soc. S. Afr., 40, 373±80. Beyers, C.J.d.B. & Goosen, P.C. (1987) Variations in fecundity and size at sexual maturity of female rock lobster Jasus lalandii in the Benguela ecosystem. S. Afr. J. Mar. Sci., 5, 513±21. Beyers, C.J.d.B. & Wilke, C.G. (1990) The biology, availability and exploitation of rock lobster Jasus lalandii off South West Africa/Namibia, 1970±1980. Invest. Rep. Sea Fish. Res. Inst. S. Afr., 133, 1±56. Beyers, C.J.d.B., Wilke, C.G. & Goosen, P.C. (1994) The effects of oxygen deficiency on growth, intermoult period, mortality and ingestion rates of aquarium-held juvenile rock lobster Jasus lalandii. S. Afr. J. Mar. Sci., 14, 79±87.

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Boyd, A.J. (1983) Intensive study of the currents, winds and hydrology at a coastal site off central South West Africa, June/July 1978. Invest. Rep. Sea Fish. Inst. S. Afr., 126, 1±47. Cockcroft, A.C. (1997) Biochemical composition as a growth predictor in male west-coast rock lobster (Jasus lalandii). Mar. Freshwat. Res., 48, 845±56. Cockcroft, A.C. & Goosen, P.C. (1995) Shrinkage at moulting in the rock lobster Jasus lalandii and associated changes in reproductive parameters. S. Afr. J. Mar. Sci., 16, 195±203. Cockcroft, A.C. & Payne, A.I.L. (1999) A cautious fisheries management policy in South Africa: the fisheries for rock lobster. Mar. Pol 23, 587±600. Cockcroft, A.C., Groeneveld, J.C. & Cruywagen, G.C. (1995) The influence of depth, latitude and width of the continental slope on the size distribution and availability of spiny lobster Palinurus delagoae off the east coast of South Africa. S. Afr. J. Mar. Sci., 16, 149±60. Cockcroft, A.C., Schoeman, D.S., Pitcher, G.C., Bailey, G.W. & van Zyl, D.L. (2000) A mass stranding, or `walkout', of West Coast rock lobster Jasus lalandii in Elands Bay, South Africa: causes, results and implications. Crustacean Issues, 12, 673±688. Crawford, R.J.M., Cruickshank, R.A., Shelton, P.A. & Kruger, I. (1985) Partitioning of a goby resource amongst four avian predators and evidence for altered trophic flow in the pelagic community of an intense, perennial upwelling system. S. Afr. J. Mar. Sci., 3, 215±28. Cruywagen, G.C. (1997) The use of generalized linear modelling to determine inter-annual and inter-area variation of growth rates: the Cape rock lobster as example. Fish. Res., 29, 119±31. De Dekker, A.H.B. (1970) Notes on an oxygen-depleted subsurface current off the west coast of South Africa. Invest. Rep. Div. Fish. S. Afr., 84, 1±24. Dugdale, R.C. (1983) Effects of source nutrient concentrations and nutrient regeneration in production of organic matter in coastal upwelling centers. In Coastal Upwelling: Its Sediment Record. Part A. Responses of the Sedimentary Regime to Present Coastal Upwelling (Ed. by E. Suess & J. Thiede), pp. 107±22. Plenum Press, New York, USA. Goosen, P.C. & Cockcroft, A.C. (1995) Mean annual growth increments for male west coast rock lobster Jasus lalandii, 1969±1993. S. Afr. J. Mar. Sci., 16, 377±86. Grobler, C.A.F. & Noli-Peard, K.R. (1997) Jasus lalandii fishery in post-independence Namibia: monitoring population trends and stock recovery in relation to a variable environment. Mar. Freshwat. Res., 48, 1015±22. Groeneveld, J.C. (1997) Growth of spiny lobster Palinurus gilchristi (Decapoda: Palinuridae) off South Africa. S. Afr. J. Mar. Sci., 18, 19±29. Groeneveld, J.C. (in press). Stock assessment, ecology and economics as criteria for choosing between trap and trawl fisheries for spiny lobster Palinurus delagoae. Fish. Res. Groeneveld, J.C. & Cockcroft, A.C. (1997) Potential of a trap-fishery for deep-water rock lobster Palinurus delagoae off South Africa. Mar. Freshwat. Res., 48, 993±1000. Groeneveld, J.C. & Melville-Smith, R. (1995) Spatial and temporal availability in the multispecies crustacean trawl fishery along the east coast of South Africa and southern Mozambique, 1988± 1993. S. Afr. J. Mar. Sci., 15, 123±36. Groeneveld, J.C. & Rossouw, G.J. (1995) Breeding period and size in the south coast rock lobster, Palinurus gilchristi (Decapoda: Palinuridae). S. Afr. J. Mar. Sci., 15, 17±23. Groeneveld, J.C., Cockcroft, A.C. & Cruywagen, G.C. (1995) Relative abundances of spiny lobster Palinurus delagoae and slipper lobster Scyllarides elisabethae off the east coast of South Africa. S. Afr. J. Mar. Sci., 16, 19±24. Holthuis, L.B. (1991) Marine lobsters of the world. An annotated and illustrated catalogue of species of interest to fisheries known to date. FAO Fisheries Synopsis, 125, 292 pp. Matthews, J.P. & Smit, N.L. (1978) Trends in the size composition, availability, egg-bearing and sex ratio of the rock lobster Jasus lalandii in its main fishing area off South West Africa, 1958±1969. Invest. Rep. Sea Fish. Branch S. Afr., 103, 1±38.

120 Spiny Lobsters: Fisheries and Culture Matthews, S.G. & Pitcher, G.C. (1996) Worst recorded marine mortality on the southern African coast. In Harmful and Toxic Algal Blooms (Ed. by T. Yasumoto, Y. Oshima, & Y. Fukuyo), pp. 89±92. Intergovernmental Oceanographic Commission of UNESCO, Paris, France. Melville-Smith, R., Goosen, P.C. & Stewart, T.J. (1995) The spiny lobster Jasus lalandii (H. Milne Edwards, 1837) off the South African coast: inter-annual variations in male growth and female fecundity. Crustaceana, 68, 174±83. Nelson, G. (1989) Poleward motion in the Benguela Area. In Coastal and Estuarine Studies, Vol. 34 (Ed. by S.J. Neshyba, C.N.K. Mooers, R.L. Smith, & R.T. Barber), pp. 110±30, Springer, New York. Newman, G.G. & Pollock, D.E. (1971) Biology and migration of rock lobster Jasus lalandii and their effect on availability at Elands Bay, South Africa. Invest. Rep. Div. Fish. S. Afr., 94, 1±24. Newman, G.G. & Pollock, D.E. (1974) A mass stranding of rock lobsters Jasus lalandii (H. MilneEdwards, 1837) at Elands Bay, South Africa (Decapoda, Palinuridae). Crustaceana, 26, 1±5. Officer, C.B. & Ryther, J.H. (1980) The importance of silicon in marine eutrophication. Mar. Ecol., 3, 83±91. Palha de Sousa, B. (1992) Stock assessment of the deep-water spiny lobster Palinurus delagoae off Mozambique. Rev. Invest. Pesqueira Maputo, 21, 29±40. Pollock, D.E. (1982) The fishery for and population dynamics of west coast rock lobster related to the environment in the Lambert's Bay and Port Nolloth areas. Invest. Rep. Sea Fish. Inst. S. Afr., 124, 1±57. Pollock, D.E. (1986) Review of the fishery for and biology of the Cape rock lobster Jasus lalandii with notes on larval recruitment. Can. J. Fish. Aquat. Sci., 43, 2107±17. Pollock, D.E. (1987) Simulation models of rock-lobster populations from areas of widely divergent yields on the Cape west coast. S. Afr. J. Mar. Sci., 5, 531±45. Pollock, D.E. (1994) The fisheries for two Jasus species of the South-east Atlantic and for Palinurus gilchristi off the southern Cape coast of South Africa. In Spiny Lobster Management (Ed. by B.F. Phillips, J.S. Cobb, & J. Kittaka), pp. 91±102. Blackwell Scientific Publications, Oxford, UK. Pollock, D.E. & Augustyn, C.J. (1982) Biology of the rock lobster Palinurus gilchristi with notes on the South African fishery. Fish. Bull. S. Afr., 16, 57±73. Pollock, D.E. & Bailey, G.W. (1986) Rock lobster stranding at Elands Bay, March 1986. S. Afr. Shipping News Fishing Indust. Rev., June, p. 31. Pollock, D.E. & Beyers, C.J.d.B. (1981) Environment, distribution and growth rates of west coast rock-lobster Jasus lalandii (H. Milne Edwards). Trans. R. Soc. S. Afr., 44, 379±400. Pollock, D.E. & Shannon, L.V. (1987) Response of rock-lobster populations in the Benguela ecosystem to environmental change ± a hypothesis. S. Afr. J. Mar. Sci., 5, 887±99. Pollock, D.E., Cockcroft, A.C. & Goosen, P.C. (1997) A note on reduced rock lobster growth rates and related environmental anomalies in the southern Benguela, 1988±1995. S. Afr. J. Mar. Sci., 18, 287±93. Tomalin, J.B. (1993) Migrations of spiny rock-lobster, Jasus lalandii, at LuÈderitz: environmental causes, and effects on the fishery and benthic ecology. M.Sc. dissertation, University of Cape Town, South Africa, 99 pp.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 6

The State of the Lobster Fishery in North-east Brazil A.A. FONTELES-FILHO Instituto de CieÃncias do Mar, Universidade Federal do CearaÂ, Av. da AbolicËaÄo, 3207-Fortaleza, CE 60165-081, Brazil

6.1

Introduction

The continental shelf off the north-east region of Brazil is endowed with stable hydrological conditions characterized by high temperature and salinity (owing to small river drainage), and by the presence of reef formations on its inner band (below 20 m depth) and calcareous algae on its outer band, a substrate that makes up the ideal habitat for tropical spiny lobsters of the genera Panulirus and Scyllarides (Coutinho & Morais, 1970). It consists of a mixture of red algae (Rhodophyceae), mainly of the genus Lithothamnium, and green algae (Chlorophyceae), represented by the genera Halimeda, Udotea and Penicillus. This shelf is mostly narrow (average width 65 km), and in zones where there is hardly any river discharge the substrate of calcareous algae may be found fairly nearer the coast, providing excellent conditions for shelter, feeding and growth of juvenile lobsters (Paiva & Fonteles-Filho, 1968; Fonteles-Filho & Ivo, 1980). The occurrence of spiny lobsters off north-east Brazil had long been reported, but because of unfavourable economic and social conditions there was no commercial exploitation until 1955 and they were used only for home consumption or as bait in the finfish fisheries. Since then, lobster tail exportations (95% of total production) have had a manifold increase over the years, reaching a maximum of 3638 t (tail weight) and US $99.3 million in revenues in 1991. The chief commercial fishing grounds lie between longitudes 35 W and 47 W, and latitudes 2 300 N±18 S (Fig. 6.1), with a total surface area of 83 552 km2. In the regional context, Ceara state holds an outstanding position as the leading lobster producer, with 27.6% (23 088 km2) of the total area, 52.3% of the catch (4052 t) and 43.5% (7302 t) of the carrying capacity (Fonteles-Filho & GuimaraÄes, 1999). Four species of lobster are found in the catch: Caribbean spiny lobster, Panulirus argus, smoothtail spiny lobster, Panulirus laevicauda, spotted lobster, Panulirus echinatus, and flat lobster, Scyllarides brasiliensis. The first two make up almost the whole catch, but P. echinatus and S. brasiliensis are said to have become quite frequent in landings from the eastern and north-eastern grounds, respectively. Panulirus argus are bigger, more fertile, heavier and more abundant (56.5% in numbers and 70.6% in weight), but grow a little more slowly and are found over a much wider area than P. laevicauda, which are distributed mainly in the inner shelf (Fonteles-Filho, 1992). Moreover, in the northern and southern grounds, where the 121

122 Spiny Lobsters: Fisheries and Culture

Fig. 6.1 Chart of lobster fishery grounds (with surface area in parentheses) off North-east Brazil.

calcareous algae substrate occurs further off the coast, P. argus is overwhelmingly dominant (Buesa Mas et al., 1968; Buesa Mas & Paiva, 1969; Fonteles-Filho, 1992).

6.2

The fishery background

The fishery concentrated at first on the north-eastern and eastern grounds, with Fortaleza and Recife as the fleet's home ports, respectively. With the first signs of stock depletion and low catch rates following a very rapid fishing effort increase in 1965±1973, the fishery expanded westward to the northern grounds in 1976, and southward to the southern grounds, in 1982. Being the capital city of the most lobster-rich Brazilian state, Fortaleza, because of its strategic position, has taken the lead as an exporting outlet from which 78% of the catch is shipped to the international market (Fonteles-Filho & GuimaraÄes, 1999). The known distribution area of lobsters in Brazil has been undergoing constant increase, as the fleet moves further out to more distant, unexploited fishing grounds, in order to make up for the depletion of those nearer the busy fishing harbours of Fortaleza, Recife and IlheÂus (Fig. 6.1) and to meet the growing market demand for lobster tails. This expansion of the fishing area was accompanied by an evolution of fishing gear and craft. Until the early 1960s fishing was carried out from wooden rafts and sailing canoes in shallow, coastal waters, and the use of bully-nets was still rewarding. With the need for increased catches of lobsters, the fleet's deployment further to distant waters was inevitable and this called for larger, swifter boats, able

The State of the Lobster Fishery in North-east Brazil

123

to cope with rough weather conditions and to stay at sea for up to 50 days. Different types of gear, similar to the Florida pot, were tested, resulting in the present 0.25 m3 hexagonal one, made out of a wooden frame and galvanized chicken wire with 5-cm meshes, and a funnel-shaped passage entrance on the front side. In the late 1980s a double-entrance, larger and lighter trap went into operation in a few fishing communities, with the advantage of being much more durable (life span of 3 years, compared with 4 months of the conventional trap) and amenable to use in large numbers by sailcraft. A 24-h fishing operation is performed in two halves, the diurnal one for both laying down and retrieval of as many as 600 traps (by large boats) distributed in 20-unit lines, and the nocturnal one as the effective fishing time. The standard effort varies in proportion to the boat's gross tonnage (Fonteles-Filho et al., 1985) and is given in number of trap-days by considering that one trap is equivalent, in fishing power, to 13.5 m of gill net and 0.5 double-entrance trap (Castro e Silva & Rocha, 1999). In the mid 1970s still another type of gear, the gill net, was introduced, bringing considerable changes to the fishing strategy. A new contingent of sailing rafts came back into operation because of their suitability for working with a gear that does not require large deck space, as does the trap. As a consequence, the number of both large boats (bigger than 16 m in overall length) and sailing rafts in the fleet is constantly increasing, and artisanal techniques which had their heyday in the 1960s have come back into play. This is because while trap fishing is profitable only when the largest possible area can be covered in a single trip, gill-net fishing has lower operational costs in shorter trips, and is highly efficient in shallow, coastal waters where the nets can be adequately laid on the substrate (Paiva et al., 1973). Diving has also been a quite common, but illegal (hence the underestimation of its take) lobster-catching method, in the eastern grounds where there is a predominance of reef and rocky substrates, and clear waters. Fishers make use of an air compressor in diving operations and, as fishing gears, a tow net intended for large lobster aggregations, and a bag net for putting away individual lobsters dislodged from the crevices with the aid of a gaffe. Fishing effort is much heavier in zones up to 40 km off the coast in grounds with less than the average abundance of P. argus (Ig = 0.80) and in grounds with more than average abundance of P. laevicauda (Ig = 1.23), as measured by Gulland's (1956) concentration index, Ig = ‰…Ai †…Ci =fi †Š=‰…Ai Ci †=fi Š, where Ai, Ci and fi are surface area, yield and fishing effort, respectively, in a given geographical block i. The observed difference in catchability indicates that the latter species, having the inner shelf as the preferential habitat, is much more vulnerable to fishing than the former and therefore has a higher chance of being overexploited. Density [catch per unit effort (CPUE) per 2315 km2 geographical block] has a nearly symmetrical frequency distribution, with 95% of the observations in the range 0.066±0.870 kg/ trap-day (P. argus) and a positive asymmetrical distribution, with 95% of the observations in the range 0.027±0.491 kg/trap-day (P. laevicauda) (Fonteles-Filho, 1997).

124 Spiny Lobsters: Fisheries and Culture 6.3

Biological background

Given the shape of the Brazilian coastline (Fig. 6.1), with the South Equatorial Current moving westwards and the Current of Brazil moving southwards, and the presence on the shelf of a more or less permanent closed circulation which may reduce the loss of larvae to the deep-ocean waters (Chekunova, 1972), the catch may originate from at least two stock units. Thus, between them there should be differences in size composition, reproduction and growth parameters, feeding habits, yield and interspecific relationships. However, owing to the impossibility of sorting out the catch according to its origin, one management unit in the whole fishing area has been adopted for the purposes of research and management (Paiva, 1974). Sampling for size composition and biological features such as time and frequency of spawning, size at first sexual maturity, sex ratio and growth patterns has been undertaken since 1962, at Fortaleza, based on the assumption that the centralized landing system provides a good representation of the management unit. The catch landed at Fortaleza is composed of an assorted assemblage of individuals coming from the fishing grounds in unknown proportions. Optimum sample sizes of the landings were set up as 250 individuals (P. argus) and 200 individuals (P. laevicauda), and since 1976 only the lobster tails have been measured, their length being converted to total length (TL) by means of regression equations (Fonteles-Filho & Ferreira, 1990). Exportation data are given as lobster weight by grade categories from types 2 (71 g tails) to 20 (567 g tails). Types 2 and 3 figures, when converted to numbers, provide a rough estimate of the proportion of juveniles (especially of P. argus) in the catch. Several individual and population characteristics which are relevant to understanding the fisheries biology and dynamics of lobster stocks under fishing pressure are listed in Table 6.1. Moulting of lobsters can occur in all months, but individuals in the adult phase moult twice a year, with highest intensities in January and July±August. The main breeding seasons occur in January±April, September±October (P. argus) and January±May (P. laevicauda) (Mesquita, 1973; Mesquita & Gesteira, 1975). Considering a 120-day breeding cycle, the female's ovaries take 25.4 days to develop, 5.6 days to mature, 47.3 days to ripen, and 41.7 days to become spent and begin to recover (Soares et al., 1998). Sizes at first maturity are 202 mm TL (65 mm carapace length [CL]) for P. argus and 168 mm TL (59 mm CL) for P. laevicauda, which are also set as minimum legal sizes in fishery regulations (Soares & Cavalcante, 1985; Soares, 1998a, b). Recruitment takes place more intensively in the second quarter of the year (P. argus) and in the third quarter (P. laevicauda) ± see Fonteles-Filho (1986). It is thought that the overlapping, but not coincident, spatial distributions of the two species, and the high density of juveniles in the coastal zone work as adaptation processes enabling individuals to avoid direct competition for food and shelter, and to endure rates of fishing mortality as high as 79% (Table 6.1). Thus, while P. argus are significantly more abundant from February to July,

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Table 6.1 Biological characteristics of Panulirus argus and Panulirus laevicauda stocks off North-east Brazil, 1965±1997 Characteristics

P. argus

P. laevicauda

Size range (mm TL) Mean body length (mm TL) Mean body weight (g) Mean age (years)

114±393 217 415 4.2

101±335 184 255 3.9

Asymptotic length (mm TL) Asymptotic weight (g) Growth coefficient (K) Mean growth rate (mm/year) Mean absolute fecundity (no. of eggs)

438 3163 0.163 29 294 175

380 1805 0.171 27 166 036

Mean relative fecundity (eggs/g body weight) Reproductive potential (1012 eggs) Stock numbers (106) Stock biomass (t)

630 1.1 46.7 18 795

597 0.6 27.6 7128

Stock density (ind./km2) (kg/km2) Total mortality coefficient (Z) Natural mortality coefficient (M)

955 384.2 1.31 0.36

564 145.7 1.48 0.39

Rate of exploitation (E) Catch (t) Annual mean MSY

0.68

0.79

5690 6862

2186 2727

32.4 24.2

32.5 20.7

0.175

0.067

0.204

0.115

Fishing effort (106 trap-days) Annual mean fopt CPUE (kg/trap-day) Annual mean Uopt

P. laevicauda do not show a significant variation in abundance concerning time of the year (Fonteles-Filho, 1997). Soares et al. (1998) have provided clear evidence of batch spawning through the observation of females with ripe ovaries carrying eggs and intact/eroded spermatophores. Further, it was found that successful breeding is dependent on the female being inseminated as soon as it becomes sexually mature. Fecundity is size specific (Ivo & Gesteira, 1995), but owing to various factors (e.g. condition), 85.4% and 91.2% of the reproductive potential are concentrated in the intermediate size ranges of 200±280 mm TL (64±94 mm CL) in P. argus (L1 = 154 mm CL), and

126 Spiny Lobsters: Fisheries and Culture 170±220 mm TL (60±81 mm CL) in P. laevicauda (L1 = 136 mm CL) (Ivo, 1975; Ivo & Gesteira, 1986). Thus, removal of the larger, more fecund females by the fishery is not likely to bear significantly upon the reproductive potential of the population. No information is available on the timing of larval release or on how they come ashore as pueruli, but it is certain that coastal reefs are important nursery grounds for P. laevicauda (no data are available on P. argus), because 78.8% out of 635 lobsters sampled for size, in 1967, were up to 100 mm TL (33 mm CL) juveniles (Paiva & Costa, 1968). In both species, P. argus and P. laevicauda, males are slightly larger (219 mm TL, 71 mm CL and 184 mm TL, 66 mm CL, respectively) than females (217 mm TL, 70 mm CL and 183 mm TL, 65 mm CL, respectively). Males are predominant in the catch and more so in the legal sizes (53.0% and 58.4%) than in sublegal sizes (51.2% and 53.1%), in P. argus and P. laevicauda, respectively. The disproportion in number of males is even higher during the spawning season (Fonteles-Filho, 1979), which may imply either a reduced vulnerability of females while breeding, or that the need for more than one mating to ensure fertilization requires the intervention of different males. The catchable stock of P. argus and P. laevicauda is in the range of 114±393 mm TL (34±136 mm CL) and 101±335 mm TL (33±130 mm CL). The length distribution of both species is approximately normal, with mean lengths of 71 mm CL and 65 mm CL and positive asymmetry of 0.497 and 0.087. The commercial catch is maintained by three age groups in P. argus (3±5 years, 169±272 mm TL, 53±91 mm CL) and two age groups in P. laevicauda (3±4 years, 152±217 mm TL, 53±79 mm CL) accounting for 85.5% and 87.3% of the annual production, respectively. This implies that the fishery is supported by two or three intensively fished year classes which recruit into the legal size range every year (Fonteles-Filho et al., 1988). If variation in cohort strength can be assessed from annual variation of the proportion of sublegal lobsters in the catch (thought of as an index of recruitment strength), there seems to be a 5±6-year cycle in the peak contribution of recruitment to adult stock as inferred from data from the period 1965±1997 (Fig. 6.2). It is possible that as a consequence of high fishing mortality, the stock turnover rate has increased, with an equivalent decrease in the age at first maturity and an increase in mean fecundity (Fonteles-Filho & Maia, 1987).

6.4

Economic background

Brazilian fisheries have taken advantage of a large fishing area, so that deployment of the fleet has been useful for offsetting the decline in the near-water grounds, but at expense of increasing operational costs. However, since fishery is still looked upon as a socially rather than economically important activity, taxes have been reduced to allow for eventual economic losses by the fishing industry.

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127

Fig. 6.2 Proportion of sublegal lobsters Panulirus argus and Panulirus laevicauda, off Northeast Brazil, 1965±1997.

The Brazilian fishermen land the world's second largest catch of warm-water lobster species. Average annual catches for the period 1955±1997 of yield (live weight) and exportation (tail weight) were 4914 t and 1638 t (P. argus), and 1804 t and 601 t (P. laevicauda). Total landings show a trend for stabilization since 1969, despite rather low values in certain years, distributed in three production cycles peaking at 1962, 1978±1979 and 1991 (Fig. 6.3). The lobster fishery is ubiquitous along the coast of north-east Brazil and thousands of shore workers are associated with processing and shipping. Therefore, it is important for the Brazilian fishing sector to optimize the value of this industry by providing a strong harvest and an increased profitability. Its economic structure comprises the following elements: l l l

l

processing plants capable of overseeing the phases of catching, storing, processing and marketing individual boat-owners, sometimes organized as co-operatives, who supply the industry with lobsters middlemen, most of the time hired by the processing plants to supply them with small quantities of lobsters bought from boat-owners in the artisanal fishery communities fishermen, employed by the industry, or working as independent operators in the raft fishery.

128 Spiny Lobsters: Fisheries and Culture

Fig. 6.3 Annual yeild (live weight) of lobsters Panulirus argus and Panulirus laevicauda, off North-east Brazil, 1965±1997.

Operational costs make up 70.8% of total costs and vary in a direct proportion to boat size, labour being the single most expensive item with the highest participation independent of boat size and fishing craft (Carvalho et al., 1996). In recent years the processing plants have released their control of the production system in favour of individual boat-owners and middlemen, preferring to operate as mere buyers of lobster tails for processing and exportation. This change in economic strategy means that a given amount of lobsters arriving at the processors may represent either the catch of a large boat or a small amount brought by a middleman, or both, and may have been caught by different types of gear, including commercial diving. The difficulties of performing adequate sampling of the landings are very great, because it is virtually impossible to allocate the catch accurately to the different fishing grounds or gear. The world-wide interest in this luxury commodity, and resultant high prices, have caused a substantial increase in fishing effort in what is an open-entry fishery characterized by high economic inefficiency. The present catch could be more economically obtained with much smaller inputs of labour and capital investment. In Brazil, this situation has been further aggravated by two aspects: (1) a lack of alternative employment that has stimulated what might be called a `lobster rush' to capture by whatever means are at hand, namely traps, gill nets and diving; and (2) a centralized system of lobster production by large boats in long-distance fishing trips (Fonteles-Filho, 1994). Overall, the benefits of the high prices received for lobster

The State of the Lobster Fishery in North-east Brazil

129

tails have been outweighed by high operational costs in some years, and the economic equilibrium point may have even been passed. Nevertheless, the fact that fishing is a high-risk economic activity, generating ancillary industries and employment opportunities, has justified its classification as a socio-economic activity, which is thus entitled to government support such as tax and financial subsidies. A peculiarity of the Brazilian fishery is the tailing of lobsters at sea so that only the tail is returned for processing at the plants on shore, hindering the adaptation of the boats for bringing in live individuals and causing the loss of commercial value by Brazilian lobster tails in the US market, where they reach an average ex-warehouse price of US $11.00/kg lower than that of the similar Australian product. In 1990, a small but promising trade was started for exporting whole cooked lobsters caught by small boats on short trips.

6.5

Fisheries management and the state of the stocks

Lobster fishery management in Brazil is undertaken by a national body, the Institute for the Environment and Natural Renewable Resources (IBAMA), with agencies in all states, whose main task is to draw up the pertinent legislation and carry out its enforcement. Several steps have been taken since 1976 to protect lobster stocks in Brazil. It is illegal to land, sell and transport lobsters smaller than 65 mm CL (P. argus) and 59 mm CL (P. laevicauda). A closed season has been set up of different durations (45±130 days) and months (from November to April), but since 1987 it has been fixed from 1 January to 30 April (120 days) every year. The taking of egg-bearing females is prohibited (Fonteles-Filho, 1994). Fishing with bottom gill nets and by commercial diving (a very common practice nowadays) is forbidden on the grounds that both are non-selective fishing methods, and gill nets cause damage to the calcareous algae substrate during their hauling operations. Unlike most countries, in Brazil lobsters may be processed, cut up or dismembered on board (Paiva, 1967; Ivo, 1996). The minimum legal size for P. argus, equivalent to 65 mm CL, is smaller than that in USA (Florida) and Caribbean countries, but lobsters mature younger in warm climates, so this size is well above the smallest length (51 mm CL) at which P. argus females attain sexual maturity in Brazil. Thus, the spawning stock is fairly well protected against recruitment overfishing (Fonteles-Filho, 1986). The proportion of juveniles in the catch of P. argus decreased from 35.2% in the pre-regulation period (1962±1975) to 21.3% in the regulation period (1976±1997), and increased in P. laevicauda from 23.1% to 27.9%. The establishment of a minimum legal size seems to have been less efficient in preventing the catch of juvenile P. laevicauda because there has been a relatively higher rate in increase of gill-net fishing and diving, methods that are more effective in shallower waters,

130 Spiny Lobsters: Fisheries and Culture where that species is more abundant. This situation could lead to a process of replacement by its closer competitors, namely spiny lobsters P. argus and P. echinatus, flat lobsters (e.g. Scyllarides brasiliensis) and crabs (e.g. Carpilius corallinus). Despite the decrease in effective fishing time per year, which has varied from 215 to 320 days, through a closed season aimed at reducing fishing effort and protecting egg-bearing females by coinciding with the main spawning season, effort has increased at a significant linear proportion with time. Yield and effort grew harmonically from 1956 to 1975, but afterwards effort continued to rise and yield decreased, so that mean values of yield, effort and CPUE for 1980±1997 reached the following proportions, in percentages, of their respective optimum values: for P. argus, Y = 90.2, f = 134.5 and U = 66.7; for P. laevicauda, Y = 75.0, f = 191.8 and U = 39.1. Cohort analysis and surplus yield models have been used to assess the potential production of lobster populations in north-east Brazil. Maximum sustainable yields have been estimated at 6862 t (P. argus) and 2727 t (P. laevicauda), which are obtainable by different quantities of fishing effort, namely 33.8 million trap-days and 23.7 million trap-days (Fig. 6.4). Fonteles-Filho & GuimaraÄes (1999) assessed the effect of varying mortality factors, after the Thompson & Bell method (Sparre & Venema, 1997) and found that the maximum yield per recruit could be achieved by F values of 0.63 (P. argus) and 0.48 (P. laevicauda). A reduction of the fleet by 30.2%

Fig. 6.4 Surplus yield curves of lobsters Panulrius argus and Panulirus laevicauda, off Northeast Brazil, 1965±1997.

The State of the Lobster Fishery in North-east Brazil

131

would stabilize fishing effort around 37 million trap-days, and hence stabilize the optimum socioeconomic rent from the lobster fishing sector. It is a widespread, mistaken view that the main method of ensuring the attainment of the minimum sustainable yield (MSY) is by protecting reproducing lobsters by means of a minimum legal size and banning the catching of egg-bearing females. In Brazil, these precepts were totally disregarded until 1975 and even with the implementation of management action since 1976, egg-bearing females have continued to be caught and a high proportion of juveniles still appears in the catch (Fonteles-Filho & Mendes, 1989). However, the length structure of both species has managed to remain fairly stable over the years, as shown by the low coefficients of variation of the annual mean, namely 5.5% (P. argus) and 2.9% (P. laevicauda), around their long-term values: 217 mm TL and 184 mm TL, respectively (Fig. 6.5). This was possible through the fishery expansion whereby the traditional north-eastern and eastern grounds were partly forsaken for the more promising southern grounds, inhabited by individuals that had a larger mean size because they were in an unfished stock (Fonteles-Filho et al., 1988). From the analysis of length distributions by seasons of the year, recruitment is thought to be more intensive in the second quarter in P. argus, and in the third quarter in P. laevicauda. Although there is no evidence to indicate a decline in absolute recruitment, the lobster populations probably have become younger, so

Fig. 6.5 Mean total length values of lobsters Panulirus argus and Panulirus laevicauda, off North-east Brazil, 1965±1997.

132 Spiny Lobsters: Fisheries and Culture that the recruits ought to have diminished in terms of weight and reproductive potential. Thus, assuming that growth overfishing is bound to be the main cause of declining yield in long-lived species (Cushing, 1975), and given the difficulties in enforcing the pertinent regulations, namely closed season, minimum legal size and banning the catching of berried females, it has been suggested that a way to enhance production, boost exportation and give extra protection to recruiting P. laevicauda would be to move the closed season from January±April over to July±October. Although every report on the lobster fishery situation in Brazil has expressed concern over declining catches, all have concluded that the main problem is still of a socioeconomic nature, i.e. reduced productivity and low average income resulting from increased effort to meet full employment needs. Are the lobster populations in Brazil at a steady state? If this means a stabilization of annual production at an MSY of 8150 t for both species (15% below the MSY of 9589 t), the answer is `yes'. This has been achieved, from the biological viewpoint, through a relatively successful control of the catch of the reproductive and juvenile stocks and, from the economic viewpoint, by considering the fishery as a primary sector activity where a high employment level must be maintained even at the cost of granting subsidies to the fishing enterprises. Given the large size of the total fishing area a virgin share of the population becomes available to the fleet every time fishing hits unexploited grounds. Thus, a new management approach may be suggested whereby a year-round schedule of fishing operations is set up to protect bounded areas which would be exploited in turn, while the others were still in the process of recovery.

References Buesa Mas, R. & Paiva, M.P. (1969) Pesquerias de la langosta Panulirus argus (Latreille) en el Brasil y en Cuba. Arq. Cien. Mar., 9, 77±81. Buesa Mas, R., Paiva, M.P. & Costa, R.S. (1968) Comportamiento biologico de la langosta Panulirus argus en el Brasil y en Cuba. Rev. Bras. Biol., 28, 61±70. Carvalho, R.C.A., Ferreira, C.R.C., Vasconcelos, J.A., Oliveira, M.Y.S. & Campos, L.M. (1996) Custos e rentabilidade de embarcacËoÄes envolvidas na pesca da lagosta no Nordeste do Brasil, 1995. Bol. Tec. Cient. CEPENE, 4, 233±61. Castro e Silva, S.M. & Rocha, C.A.S. (1999) EmbarcacËoÄes, aparelhos e meÂtodos de pesca utilizados nas pescarias de lagosta no Estado do CearaÂ. Arq. CieÃn. Mar., 32, 5±25. Chekunova, V.I. (1972) Geographic distribution of spiny lobsters and ecological factors determining their commercial abundance. Tr. Vses. Nauchno-Issled. Inst. Morsk. Rybn. Rhoz. Okeanogr., 77, 110±18. Coutinho, P.N. & Morais, J.O. (1970) DistribucioÂn de los sedimentos en la plataforma continental norte y nordeste del Brasil. Arq. CieÃn. Mar., 10, 79±90. Cushing, D.H. (1975) Marine Ecology and Fisheries, xiv + 278 pp. Cambridge University Press, Cambridge, UK. Fonteles-Filho, A.A. (1979) Biologia pesqueira e dinaÃmica populacional da lagosta Panulirus laevicauda (Latreille) no Nordeste setentrional do Brasil. Arq. Cien. Mar., 19, 1±43.

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Fonteles-Filho, A.A. (1986) InflueÃncia do recrutamento e da pluviosidade sobre a abundaÃncia das lagostas Panulirus argus e Panulirus laevicauda (Crustacea: Palinuridae). Arq. Cien. Mar., 25, 13±31. Fonteles-Filho, A.A. (1992) Population dynamics of spiny lobsters (Crustacea: Palinuridae) in Northeast Brazil. CieÃnc. Cult., 44, 192±6. Fonteles-Filho, A.A. (1994) A pesca predatoÂria de lagostas no CearaÂ: causas e consequeÃncias. Bol. Tec. Cient. CEPENE, 2, 107±31. Fonteles-Filho, A.A. (1997) Spatial distribution of the lobster species Panulirus argus and P. laevicauda in northern and northeastern Brazil in relation to the distribution of fishing effort. CieÃn. Cult., 49, 172±6. Fonteles-Filho, A.A. & Ferreira, A.H. (1990) AnaÂlise do sistema de amostragem da captura de lagostas no Nordeste do Brasil. Caatinga, 7, 175±86. Fonteles-Filho, A.A. & GuimaraÄes, M.S.S. (1999) Ciclos de producËaÄo e capacidade de carga dos estoques de lagostas do geÃnero Panulirus na plataforma continental do Estado do CearaÂ, Brasil. Arq. Cien. Mar., 32, 27±38. Fonteles-Filho, A.A. & Ivo, C.T.C. (1980) Migratory behaviour of the spiny lobster Panulirus argus (Latreille). Arq. Cien. Mar., 20, 25±32. Fonteles-Filho, A.A. & Maia, L.R.E. (1987) Estudo da dinaÃmica populacional da lagosta Panulirus laevicauda (Latreille), pelo meÂtodo da AnaÂlise de Coortes, no Nordeste do Brasil. In Anais do V Congresso Brasileiro de Engenharia de Pesca (Ed. by M. Ogawa), pp. 575±89. Grafica Batista, Fortaleza, Brazil. Fonteles-Filho, A.A. & Mendes, G.M.S. (1989) Fishing of juvenile lobsters, Panulirus argus and Panulirus laevicauda, in coastal areas off Ceara State, Brazil. Proc. SIUEC, 2, 393±402. Fonteles-Filho, A.A., Souza, A.R., CoeÃlho, A.S. & Ximenes, M.O.C. (1985) ParaÃmetros teÂcnicos e õ ndices de rendimento da frota lagosteira do Estado do CearaÂ, Brasil. Arq. CieÃn. Mar., 24, 89±100. Fonteles-Filho, A.A., Ximenes, M.O.C. & Monteiro, P.H. (1988) Sinopse de informacËoÄes sobre as lagostas Panulirus argus (Latreille) e Panulirus laevicauda (Latreille) (Crustacea: Palinuridae), no Nordeste do Brasil. Arq. Cien. Mar., 27, 1±19. Gulland, J.A. (1956) On the fishing effort in English demersal fisheries. Fish. Invest., Ser. 2, 20, 1±52. Ivo, C.T.C. (1975) Novo estudo sobre o crescimento e idade da lagosta Panulirus laevicauda (Latreille), em aÂguas costeiras do Estado do Ceara (Brasil). Arq. Cien. Mar., 15, 29±32. Ivo, C.T.C. (1996) Biologia, pesca e dinaÃmica populacional das lagostas Panulirus argus e Panulirus laevicauda (Crustacea, Palinuridae), capturadas ao longo da plataforma continental do Brasil entre os estados do Amapa e Espõ rito Santo. Tese de Doutorado, Universidade de SaÄo Carlos, 279 pp., SaÄo Carlos, Brazil. Ivo, C.T.C. & Gesteira, T.C.V. (1986) Potencial reprodutivo das lagostas Panulirus argus e Panulirus laevicauda (Crustacea: Palinuridae), no Nordeste do Brasil. Arq. Cien. Mar., 25, 1±12. Ivo, C.T.C. & Gesteira, T.C.V. (1995) AvaliacËaÄo da fecundidade individual das lagostas Panulirus argus (Latreille) e Panulirus laevicauda (Latreille). Bol. Tec. Cient. CEPENE, 3, 149±68. Mesquita, A.L.L. (1973) Aspectos cronoloÂgicos da reproducËaÄo da lagosta Panulirus argus (Latreille), no Estado do Ceara (Brasil). Arq. Cien. Mar., 13, 77±82. Mesquita, A.L.L. & Gesteira, T.C.V. (1975) EÂpoca de desova, tamanho e idade na primeira desova da lagosta Panulirus laevicauda (Latreille). Arq. Cien. Mar., 15, 93±6. Paiva, M.P. (1967) Algunos problemas de la industria langostera en el Brasil. Arq. Est. Biol. Mar. Univ. Fed. CearaÂ, 7, 105±12. Paiva, M.P. (1974) DistribuicËaÄo do esforcËo e variacËaÄo da abundaÃncia na pesca de lagosta no Estado do CearaÂ. CieÃnc. Cult., 26, 365±9. Paiva, M.P. & Costa, R.S. (1968) Comportamento bioloÂgico da lagosta Panulirus laevicauda (Latreille). Arq. Est. Biol. Mar. Univ. Fed. CearaÂ, 8, 1±6.

134 Spiny Lobsters: Fisheries and Culture Paiva, M.P. & Fonteles-Filho, A.A. (1968) Sobre as migracËoÄes e õ ndices de exploracËaÄo da lagosta Panulirus argus (Latreille), ao longo da costa do Estado do CearaÂ. Arq. Est. Biol.Mar. Univ. Fed. CearaÂ, 8, 15±23. Paiva, M.P., AlcaÃntara Filho, P., Matthews, H.R., Mesquita, A.L.L., Ivo, C.T.C. & Costa, R.S. (1973) Pescarias experimentais de lagostas com redes-de-espera, no Estado do Ceara (Brasil). Arq. Cien. Mar., 13, 121±34. Soares, C.N.C. (1998a) Tamanho meÂdio de primeira maturacËaÄo sexual da lagosta Panulirus argus (Latreille), no litoral do Estado do CearaÂ, Brasil. Arq. CieÃn. Mar., 31, 5±16. Soares, C.N.C. (1998b) Tamanho meÂdio de primeira maturacËaÄo sexual da lagosta Panulirus laevicauda (Latreille), no litoral do Estado do CearaÂ, Brasil. Arq. CieÃn. Mar., 31, 17±27. Soares, C.N.C. & Cavalcante, P.L.P. (1985) Caribbean spiny lobster (Panulirus argus) and smoothtail spiny lobster (Panulirus laevicauda) reproductive dynamics. FAO, Fish. Rep., 327, 200±17. Soares, C.N.C., Fonteles-Filho, A.A. & Gesteira, T.C.V. (1998). Reproductive dynamics of the spiny lobster Panulirus argus (Latreille, 1804) off northeastern Brazil (Crustacea: Palinuridae). Rev. Brasil. Biol., 58, 181±91. Sparre, P. & Venema, S.C. (1997) IntroducËaÄo aÁ avaliacËaÄo de mananciais de peixes tropicais. Parte 1 ± Manual. FAO Doc. Tec. Pesca, 306/1, 404 pp.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 7

The Cuban Spiny Lobster Fishery J.A. BAISRE Ministerio de la Industria Pesquera, Barlovento, Santa Fe 19 500, La Habana, Cuba

7.1

Introduction

The fishery for Panulirus argus in the Western Central Atlantic is the largest spiny lobster fishery in the world and the most valuable single-species fishery in Cuba, accounting for 60±65% of the country's gross income from fisheries products. Cuba follows Australia as the second largest exporter of spiny lobster in the world More than 60% of the catch is processed as whole cooked lobsters in nine coastal locations and exported mainly to Japan, Canada, France, Spain and Italy. The rest of the catch is processed as frozen tails, also for export, although in the last few years there has been a growing interest in exporting live lobsters. Spiny lobsters are widely distributed in all shallow-water areas with sea-grass beds and coralline growth on sandy or rocky bottom, and fishing occurs mostly at depths from 3 to 15 m in the extensive shelves of the Cuban south coast and in the less extensive shelves of the north coast, There are 250 fishing boats and 1250 fishers involved in the fishery, operating in four large management zones or subfisheries. These are partitioned into nine smaller fishing districts which are controlled by the same number of fishing enterprises (Fig. 7.1). The assignment of exclusive fishing areas to each enterprise and even to each group of boats within the enterprise is an important feature of the Cuban lobster fishery. This chapter reviews the biology, fishery and management of the spiny lobster fishery in Cuba.

Fig. 7.1 Map of Cuba showing the lobster fishing areas (shaded), the limits of the fishing zones and the location of the fishing enterprises (light circles).

135

136 Spiny Lobsters: Fisheries and Culture 7.2

Life history

After mating in shallow waters, females of P. argus may move as far as several kilometres to the edges of the reefs or coastal shelves to incubate and/or release larvae (Buesa, 1965). The larvae are planktonic in oceanic water, where they spend 6±8 months (Baisre, 1976; Alfonso et al., 1991) before the metamorphosis to the puerulus stage that migrates inshore. Puerulis arrive at the coast during every month of the year, with two main recruitment peaks during spring±summer (May±July) and autumn (September±November) (Cruz et al., 1991a). Settlement in coastal waters occurs in algal clumps of Laurencia spp. (Max & Herrnkind, 1985; Herrnkind & Butler, 1986) and occasionally into the algal web attached to submerged mangrove roots (Witham et al., 1964; Baisre, unpubl.). There, the puerulus rapidly takes on a distinctive colour pattern and within days metamorphoses into the first benthic juvenile, 6±7 mm carapace length (CL) (Cruz et al., 1986). According to Baisre (1999), sexual maturity is attained at a size of 78.5 ‹ 1.5 mm CL and does not seem to be affected by either geographical differences or fishing pressure (Table 7.1). Mating takes place mainly in February±March and the female carries the black spermatophore until March±April when the eggs are extruded, fertilized and attached to the pleopods. Details of the ovoposition process are given by Sutcliffe (1952) and Buesa (1965). Hatching occurs after 3±4 weeks, mainly during April± May. The number of eggs ranges between 159 000 and 1 629 000 and has been shown to be related to CL (in mm) by the following equation: F = 0.5911 + CL2.9666 (Cruz & LeoÂn, 1991).

7.3 7.3.1

The fishery Historical background

The history of development of the fishery for spiny lobster (P. argus) in Cuba is shown in Fig. 7.2 and the four main phases of a fishery, described by Caddy (1984), are clearly distinguished. The commercial exploitation of the spiny lobster probably began in the Gulf of BatabanoÂ, on the south coast, in the early part of the twentieth century (GarcõÂ a, 1919), although data on landings are only available since 1928. In 1927, the Cuban tariff on canned goods was increased. This not only discouraged imports but also paved the way for Cuban canneries. The first processing plant was established at La Coloma in 1933 (MartõÂ nez, 1948) but landings during the first three decades remained low, under 1000 t/year (phase I). As in Florida (Labisky et al., 1980), the Cuban fishery experienced a rapid growth (phase II) during the 1950s, associated with an increase in lobster price and the attractive US market to which of the lobster was exported as canned meat (Baisre, 1987). In the 1920s, when the bully net was introduced, the lobster fishery was carried out using nets, harpoons, tridents, octopuses (to drive the lobster from the shelter), forked poles with a running knot

The Cuban Spiny Lobster Fishery

Fig. 7.2

137

Evolution of the spiny lobster catches showing the different phases of the fishery.

and unbaited traps made of vegetable fibres. Bully nets and Antillean S-traps were the predominant fishing gear until the end of the 1960s, when they were progressively replaced by more efficient fishing systems such as pesqueros (Chapter 22) and jaulones (Baisre & PaÂez, 1981). A minimum legal size of 69 mm CL, together with a closed season, have been management tools in the spiny lobster fishery from the early years. Between 1965 and 1977 the closed season was reduced to 45 days and large quantities of undersized lobsters, principally in the Gulf of BatabanoÂ, were landed. The effects of this growth in overfishing can be seen not only in the data on size composition of the catch, but also because the highest catches of 1969 and 1976 were both followed by severe drops in 1970 and 1977, respectively (Fig. 7.2). Since 1978 the closed season has been lengthened from 1.5 to 3 months (from 1 March to 31 May), the minimum legal size limit is now strictly enforced and landings have gradually increased, rising to a peak of 13 600 t in 1985 (phase III). As shown by Cruz et al., (1992b), these regulatory measures caused a change in the mean size at first capture. In 1990 the fishery declined (phase IV) owing to very poor recruitment (Puga et al., 1991), probably associated with a dramatic mortality of juveniles caused by Hurricane Gilbert in September 1988, which caused considerable damage to the fishing grounds. Evidence for this decline in recruitment comes from the analysis of the size composition (industrial grades) of the catches (Fig. 7.3). The low abundance of juveniles during 1989 was also confirmed, by fisheries independent data, by the monitoring of nursery areas in the Gulf of Batabano (Cruz et al., 1995). In 1991, the closed season was lengthened to 4 months to reduce the fishing effort further. Further reduction in the number of fishing gears was also implemented.

138 Spiny Lobsters: Fisheries and Culture

Fig. 7.3 Size (weight) composition of the spiny lobster annual catches, based on data from the industry, during 1980±1993. The data are expressed as anomalies (percentages) of the average size for each class and for the whole period. There is a clear drop of the smallest lobster (180/230) since 1989, which corresponds with a similar drop in catches in 1990.

7.3.2

Fishing gear and boats

The Cuba spiny lobster fishery is complex because of the large number of fishing gear and techniques used by the fishermen. The main fishing gears currently used include artificial shelters (pesqueros), trap-like jaulones, unbaited traps, and old car tyres (see Cruz & Phillips, Chapter 22), although the traditional bully nets (chapingorro) are still frequently used (Fig. 7.4). A major feature of the Cuban lobster fishery has been the introduction, since the 1940s (Buesa, 1965), of the artificial shelters known as pesqueros. The use of pesqueros expanded rapidly from the 1970s and about 250 000 of these devices are employed in the fishery (Chapter 22). The jaulones are rectangular trap-like gear made with chicken wire and with large leader nets (about 50 m long) attached at the two front corners in a V-pattern. They are place singly or several together in a zigzag pattern during the migratory season (15 September to 31 December). The fishing boats are mainly of the Cayo Largo type, which are about 18 m long and constructed of timber, steel or ferrocement, although the use of fibreglass in lobster vessel building has become important in recent years. Boats of this type

The Cuban Spiny Lobster Fishery

139

Fig. 7.4 Different types of fishing gears used in the Cuban spiny lobster fishery: (a) Pesquero; (b) JauloÂn; (c) Antillean trap; and (d) bully net.

account for 81% of the fleet but small boats, from 5 to 14 m long, are also used in very shallow water. All the boats have a holding tank to keep the lobster alive. Daily, or every 2 or 3 days, depending on the volume of the catch, lobster are landed at one of the 30 holding facilities constructed at sea close to the fishing districts.

7.3.3

Seasonality and depth distribution

There is a strong seasonality in the catches of P. argus which seems to be associated with the seasonal movements of this species (Fig. 7.5). The highest catch rate occurs in June just after the start of the fishing season, then there is a progressive decline and catches are the lowest in September, when lobsters migrate from shallow areas (Buesa, 1965): this premigratory build-up is described by Kanciruk & Hernkind (1978). In September there is also a shift in climatic conditions; the temperature drops, atmospheric pressure reaches minimum values, there is a decline in photoperiod and wind velocity is at its lowest (GarcõÂ a et al., 1991a). It has been postulated that the changing autumn photoperiod and perhaps long-term temperature changes prime the lobster populations for mass migration (Kanciruk, 1980). The second peak in the catches, which usually occurs in October±November, is explained by the massive return to the shallows of lobster that have performed the offshore migration after the first autumnal storm of the season. This phenomenon, known by the fisherman as recalos or arribazones (words that in Spanish mean something arriving or something which is thrown to the coast), has been reported since the earliest days of the fishery (MartõÂ nez, 1948). There is also a definite relation between depth and/or distance from shore and the size of individual lobsters. The average size of the lobsters increases with distance

140 Spiny Lobsters: Fisheries and Culture

Fig. 7.5 Daily catches of the spiny lobster during the 1988/89 fishing season. The series have been smoothed by 7 day moving average. Note the strong peak in early September, following the passage of Hurricane Gilbert.

offshore. This feature of P. argus in Cuba (Buesa, 1965; GonzaÂlez et al., 1991) also occurs throughout the distributional range of the species and has been reported in Bermuda (Sutcliffe, 1952), the Bahamas (Kanciruk & Herrnkind, 1976), Florida (Davis, 1978; Lyons et al., 1981) and Brazil.

7.4 7.4.1

Population dynamics Size at first maturity

Although early data from Cuba (Buesa, 1965, 1972) show that a small percentage of females below 69 mm CL were carrying eggs or spermatophores, Cruz & LeoÂn (1991) have estimated 81 mm CL to be the size at first (50%) maturity of P. argus. More recently, Baisre (1999) has shown that there is a remarkable uniformity in the size at 50% maturity throughout the whole area and that fishing pressure or latitudinal differences do not seem to exert any significant influence on this population parameter. For virtually unfished stocks and in deeper waters, size at 50% maturity is close to 90 mm CL, but this difference is associated with the size composition of the samples and particularly with the fact that small females are seldom found at these depths. These data correlate well with growth estimates from Hunt & Lyons (1986), which show that a dramatic decrease in growth rates occurred in P. argus between 74 and 76 mm CL, indicating that mean size at onset of maturation is 75 mm CL. This finding is also supported by studies of other

The Cuban Spiny Lobster Fishery

141

Table 7.1 Size at 50% maturity (in mm CL) estimated by fitting a logistic curve to the cumulative proportions of females carrying eggs (E), eggs and spermatophore (SE) or ovigerous setae (OS) Source of the data

CL (mm)

Criteria of maturity

nr

Localities

r

Buesa (1965) Buesa (1965) Buesa (1965)

80.3a 78.0a 76.3a

E E E

262 1310 108

Cuba (SE) Cuba (SW) Cuba (NW)

0.9530 0.9632 0.9718

Buesa (1965) Lyons et al. (1981) Lyons et al. (1981) Gregory et al. (1982) Gregory et al. (1982)

74.7 77.7 76.9 78.3 76.9

E E SE E SE

114

Cuba (NE) Florida Florida Florida Florida

0.9913 0.9917 0.9940 0.9806 0.9870

Gregory & Labisky (1981) Kanciruk & Herrnkind (1976) Kanciruk & Herrnkind (1978) Paiva & Costa (1963)

82.6 77.5 77.3 78.5b

OS E SE SE

1074

Florida Bahamas Bahamas Brazil

0.9713 0.9987 0.9992 0.9790

Paiva & Costa (1964) Paiva & Costa (1965) Paiva & Costa (1966) Aiken (1983)

78.1b 80.5b 82.9b 87.3

SE SE SE SE

1540 783 575 1074

Brazil Brazil Brazil Jamaica

0.9944 0.9448 0.9972 0.9523

Davis (1975) GonzaÂlez-Cano (1991) Baisre (unpubl.) Baisre (unpubl.)

90.6c 90.0 88.2c 89.6c

SE SE E SE

869

Dry Tortugas Mexico Cuba (deep) Cuba (deep)

0.9996

1794 268 299

1293 1896

0.9944 0.9947

a

CL calculated from the equation Y = 2.34 + 0.337X (Cruz et al., 1991b). CL calculated from the equation Y = 2.60 + 0.343X (estimated by the author). c A practically unfished segment of the stock. b

reproductive characters such as ovigerous setae (Gregory & Labinsky, 1981) and gonadal weight (Soares & Cavalcante, 1985).

7.4.2

Growth rates

Of all the parameters of adult palinurid populations, the growth rate of individuals is probably the aspect that has been most intensively studied; despite this effort, complete descriptions of growth of spiny lobsters are surprisingly rare (Morgan, 1980). The difficulty in separating the two components of the growth process in spiny lobsters: the molt increment and the moult frequency, has been stressed by many

142 Spiny Lobsters: Fisheries and Culture authors (Aiken, 1980; Cobb & Caddy, 1989) and has been a real problem for obtaining accurate growth estimates. As pointed out by Munro (1974), the growth rate of P. argus has been investigated in detail by several authors, with fairly divergent and sometimes conflicting results. In a more recent paper (LeoÂn et al., 1995), it can be appreciated that Munro's statement still holds true. Buesa (1972), using mark±recapture techniques and growth data from animals held in the laboratory, provided the first age and estimates for P. argus in Cuba. More recent age and growth estimates using the von Bertalanffy equation and based on the mark±recapture technique are given by BaÂez et al. (1991) and Phillips et al. (1992), while growth estimates using length-frequency analysis are provided by Cruz et al. (1981) and by BaÂez et al. (1991) (Table 7.2). Estimates from Buesa (1972) and BaÂez et al. (1991) do not show significant differences between the sexes, but data from Cruz et al. (1991b) and Phillips et al. (1992) revealed the contrary and are more in agreement with studies carried out in the Florida region (Hunt & Lyons, 1986). Data on asymptotic length and growth rates (Table 7.2) also revealed that estimates from mark±recapture techniques are consistently higher than those from length frequencies. Data from Buesa (1972) seem to be an exception, but his estimates appear to be biased, probably owing to inadequacies in the tagging techniques and too much pooling of the data. Phillips et al. (1992) pointed out that in P. argus growth seems to vary markedly between localities, probably because of differences in water temperature and the length composition of the animals examined. These authors also claim that in order to improve growth estimates in this species, it will be necessary to obtain data on the growth of lobsters less than 25 mm and also greater than 125 mm CL. While growth data on lobsters less than 25 mm CL (BaÂez et al., 1991) do not seem to change the Table 7.2 Comparative values of the von Bertalanffy growth curve for Panulirus argus using different methods and data from mark-and-recapture experiments (MR) and length-frequency analysis (LF) Males L1 K (mm CL) (years)

Females L1 K (mm CL) (years)

Other references Method to fit the curve

Source of the data Author(s)

164.4 250.0

0.15 0.289

157.6 209.0

0.15 0.305

Ford-Walford MR Munro MR

Buesa (1972) BaÂez et al. (1991)

289.7 250.3 178.0 225.0

0.219 0.270 0.222 0.12

144.2 170.9 171.0 193.0

0.511 0.390 0.207 0.134

Fabens Palmer ELEFAN Fournier

MR MR LF LF

Phillips Phillips BaÂez et BaÂez et

168.7 190.0 185.0

0.22 0.31 0.23

139.4 174.0 154.0

0.31 0.24 0.19

Bhattacharya ELEFAN ELEFAN

LF LF LF

Cruz et al. (1981) LeoÂn et al. (1995) LeoÂn et al. (1995)

et al. (1992) et al. (1992) al. (1991) al. (1991)

The Cuban Spiny Lobster Fishery

143

initial part of the growth curve, the problems with the last (asymptotic) part of the curve remain. This is the probable explanation for the differences between some of the estimates presented in Table 7.2 and the maximum sizes (between 180 and 200 mm CL) reported in the literature for P. argus (Sutcliffe, 1952, Peacock, 1974; LeoÂn et al., 1995). All the previous authors have used the von Bertalanffy growth function to fit their data, although there is growing evidence that empirical growth models using moult increment and moult interval allow a better interpretation of the data (Saila et al., 1979; Morgan, 1980) and permit the development of simulation models with a greater degree of biological realism (Cobb & Caddy, 1989).

7.4.3

Recruitment

Predicting stock size and catch of spiny lobster from various indices of recruitment can be extremely useful to the industry as well as to fisheries management. Using the catch prediction system developed in Western Australia as a model (Phillips & Cruz, 1990), puerulus collectors are now installed at several locations and operating successfully (Cruz et al., 1991a) (see also Phillips et al., Chapter 19). The ability to predict the level of recruitment to the fishery 1 year in advance using the catch rate of pre-recruits, as has been done in Australia (Caputi & Brown, 1986), is another important management tool for the spiny lobster fishery. Recruitment into the fishery occurs mainly during the closed season from March to May (Cruz et al., 1991a); hence, the catches during the fishing season, opened in June, will depend on the new recruits just becoming incorporated into the fishery. The relationship between the landings of smaller lobster (industrial grade 280/320) and the catches in the next year is shown in Fig. 7.6. Cruz et al. (1995) reported a significant relationship between a juvenile index and catches in the next year (r = 0.8302, p < 0.001). The index of juvenile abundance was obtained from monthly monitoring of 60 artificial reefs made from concrete blocks and placed in a nursery area. These authors also found that the index of puerulus settlement was significantly correlated with juvenile abundance. However, their belief that the principal factor determining the level of recruitment to the fishable stock is the level of larval recruitment seems to be premature. Larval recruitment is indeed a basic factor, but survival during the early juvenile stages can also be a very important factor. There is growing evidence that the availability of abundant shelter in nursery areas is one of the bottlenecks regulating population size in spiny lobsters (Caddy & Stamatopoulos, 1990). If the availability of settlement or post-settlement habitat truly limits spiny lobster population abundance, then a strong correspondence between the supply of post-larvae and recruitment of juveniles should only be evident in area containing prime nursery habitat (Forcucci et al., 1994). Since 1965 the effective fishing effort has increased, partly because of increased effort (in the form of more gear and greater efficiency), a shorter closed season and poor enforcement of the legal minimum size until 1978 (Baisre et al., 1983). Annual

144 Spiny Lobsters: Fisheries and Culture

Fig. 7.6 Relationship between the landings of small lobster (grade 210/325) and the annual catches: (a) same year; (b) next year.

fluctuations in spiny lobster landings, however, seem to be relative modest with an average annual coefficient of variation of only 16.8% in the last 37 years. Annual variation in landing from individual subfisheries is higher, with the annual coefficient of variation ranging from 17.3 to 28.4%.

The Cuban Spiny Lobster Fishery 7.4.4

145

Mortality

Estimates of natural mortality (M) of P. argus from mark±recapture data range from 0.26 to 0.44 (Buesa, 1972). Cruz et al. (1981) have also calculated values of M from 0.53 to 0.59 by the empirical formula of Rikhter & Efanov (1976). Estimating M directly without data on fishing effort and total mortality for a series of years is problematic (Cobb & Caddy, 1989), but it has been also suggested (Caddy, 1986) that although Pauly's (1980) empirical formulae could be further refined, the method may be broadly generalized, at least until estimates of M from more direct methods are available. Cruz et al. (1981) derived another empirical, but more specific, formula derived from data on 13 lobster stocks. The inputs for the formula (M = 0.0277 0.0004, L1 + 0.5397, K + 0.0119 T) are also data on growth parameters (L1 and K) and average water temperature (T) in degrees Celsius. The results from both empirical models are quite different and for P. argus, for example, if one uses the Pauly's formula, taking K values ranging between K = 0.20 and K = 0.30 (Anon., 1981; Cruz et al., 1981) and L1 = 500 mm TL (Cruz et al., 1991b), and assume a mean water environmental temperature of 27 C, values of M are obtained ranging from M = 0.39 to M = 0.53. With the formula from Cruz et al. (1981), M values are obtained ranging from 0.2 to 0.26, which are considerably lower than both previous estimates and other M values reported in the literature. Estimation of mortality rates is spiny lobster is complicated by the lack of accurate age-based data and by the bias introduced during sampling programmes by the migratory behaviour of these animals. Values of total mortality (Z) for P. argus from Buesa (1965) range between 0.63 and 077 depending on age, but the results seem to be biased by inappropriate age-based data. Total mortality estimates from this author, recalculated using his length-frequency data and Beverton & HoltÂs (1956) ± ± ± formulation Z =  (L1 L )/(L Lc), where L is the mean length in the catch and Lc is the smallest length of animals that are fully represented in catch samples, ranges from 1.9 to 2.0, which are more in agreement with data from other highly exploited lobster populations in the region, such as those of the Bahamas (Waugh, 1980), Jamaica (Munro, 1974) and Florida (Anon., 1981). Other attempts to use catch curves to calculate mortality rates were unsuccessful and a decrease in mortality was found which seemed to be related to a trend, with recruitment decreasing with time, as suggested by Caddy (1991).

7.5

Yield models

PeÂrez et al. (1978) presented the first stock±recruitment (S/R) curve for the southeastern lobster fishery. More recently, Puga et al. (1991) used cohort analysis and surplus yield models to assess the potential yield of lobster populations in each of the four main subfisheries. Maximum sustainable yield has been estimated at 12 300 t and the authors claim that fisheries are fully exploited and that a decrease in

146 Spiny Lobsters: Fisheries and Culture recruitment has taken place in the past few years. S/R curves of the Ricker type have been calculated for each subfishery and an S/R curve, incorporating several environmental parameters, was present for the Gulf of Batabano subfishery. Data on S/R previously mentioned must be viewed with caution because it is known that larvae of P. argus in the Caribbean are distributed throughout the region (Baisre et al., 1978); although preliminary biochemical studies indicate distinct subpopulations (Menzies, 1981) and larval distribution (Alfonso et al., 1991), coupled with oceanic circulation (Garcõ a et al., 1991b) indicating the existence of favourable mechanisms for larval retention in the Cuban south coast, no conclusive evidence for local recruitment has been demonstrated. However, there is growing evidence that S/R relationships in spiny lobster are more of the asymptotic (Beverton & Holt, 1957) than the dome-shaped (Ricker, 1954) type. According to Cobb & Caddy (1989), the asymptotic nature of the relationship may explain the stability of the lobster stock as well as its resilience to continued high exploitation rates, suggesting that relatively high levels of fishing mortality might be sustained without a demonstrable decrease in recruitment. The less heavily exploited segment of the lobster population, living in deeper water (GonzaÂlez et al., 1991), is also an unknown factor commonly neglected in the calculation of S/R curves. Analyses of alternative minimum size limits utilizing the Beverton & Holt (1957) model of yield per recruit (Y/R) have been also carried out, incorporating market values for each size class (Cruz et al., 1991b). This model, which does not consider the effect of variable recruitment, incorporates estimates of growth rates, based on the von Bertalanffy growth function, and mortality rates to estimate potential yield for any desired combination of fishing mortality (F) and minimum size. Although the reliability of Y/R analysis will depend on the quality of the input data, and estimates are greatly affected by both growth and mortality rates, the analysis may be considered adequate to sustain the conclusion that the present size limits do not result in maximum yield per recruit and that an increase in size limits (from 69 mm to 77 mm CL) would increase the yield per recruit. As suggested by Cobb & Caddy (1989), excessive reliance on Y/R analysis can be hazardous if the actual number of recruits is declining, and the development of some measure for annual recruitment is strongly recommended. According to Puga et al. (1996), the jaulones allow more escapes of small-sized lobsters and as a consequence, the length at first capture (L50% = 25.5 cm TL) is higher than the corresponding length in the pesqueros (L50% = 24.2 cm TL). These authors find that jauloÂn catchability is 2.3 times higher than pesquero catchability and while in the opening of the fishing season the catchability is higher for the 3±4year-old lobsters, for the winter season (jaulones) the catchability is higher for age groups 4 and 5. Puga et al. (1996) also assessed the effect of varying the fishing effort in both seasons using a Thompson and Bell model. According to these authors, the maximum yield per recruit could be achieved by decreasing the fishing effort in season 1 to 20% of the current level and increasing the effort in season 2 by 20±40%.

The Cuban Spiny Lobster Fishery 7.6

147

Management and fisheries forecasting

Besides the enforcement of fishery regulations and the limited entry to the fishery, successful management of the Cuban spiny lobster fishery will depend on an accurate database, the development of some measure for annual recruitment and a more precise measure of fishing effort. A detailed data-gathering system on the spiny lobster fishery has now been established. Each enterprise provides monthly information on the number of boats fishing, the gear fished and the catches made by each boat. In addition, a biologist stationed at each enterprise collects field data on the size composition, sex ratio stage of reproductive females, etc., of the catch. These data are then summarized at the Fisheries Research centre and rapid processing of data can be achieved (Phillips & Cruz, 1990). Enforcement of a legal minimum size together with the poor performance of the pesqueros, means that many undersized lobsters, depending on the zone and on the season, are caught, handled and returned to the sea. Unfortunately, the magnitude and adverse impact of such practices on survival and growth are poorly known and must be assessed in the future.

7.7

Problems and perspectives

Strict enforcement of fisheries regulations, the limited entry of new boats into the fishery, the regulation of the number of fishing gears, the assignment of exclusive fishing zones and the data-gathering system all point to the Cuban fishery being one of the best-managed spiny lobster fisheries in the world. Nevertheless, more intensive biological research together with new approaches to stock assessment are needed for the refinement of estimates of stock sizes and for improving the management system. Fishing capacity will continue to increase, both through technological improvements to boats and fishing gear, and through learning effects owing to improved skipper skills that will require continual effort calibration (Cobb & Caddy, 1989). To overcome difficulties to obtain accurate data on fishing effort, the long data series on size composition of the catch, together with data from the processing industry, can be used to estimate mortality rates for a long period, and production models (Csirke & Caddy, 1983) must be tested. These models also permit adjustments for departures from equilibrium (Caddy, 1986). A different and perhaps easier and less expensive approach could be the use of heuristic time-series analysis based on the long data series on catches and environmental parameters now available for the fishery. According to Fogarty (1989) it may be possible to obtain more accurate forecast using a heuristic model than a structural model. Using an autoregressive moving average (ARIMA) model, spiny lobster catches have been estimated and a simple moving average model for the

148 Spiny Lobsters: Fisheries and Culture differenced series (ARIMA 0,1,1) is capable of describing adequately the dynamics of the series (Fig. 7.7) (Baisre unpubl.). Although the mode of action of the pesqueros, the principal fishing gear, is not well understood, there is a common belief among fishermen that they not only concentrate the lobster but also provide shelter from predators, thereby increasing survival and hence yield. Although few experimental data are available to support this belief, there is growing evidence that the number and quality of available shelters limit the population density of lobsters (Eggleston et al., 1990; see Chapter 22). A reassessment of growth data and the development of empirical models that combine the separate elements of increment and frequency to drive the growth curves to the yield-per-recruit model are more realistic than the Beverton±Holt yieldper-recruit model, which incorporated the von Bertalanffy growth function (Saila et al., 1979) There is a remarkable stability in the Cuban lobster fishery, particularly given the high unit value and often growing and uncontrolled fishing effort. This stability seems to imply a considerable population resilience, perhaps owing to a high degree of density dependence somewhere in the system (Caddy, 1990). There is also a growing body of evidence suggesting that rates of both growth and reproduction in spiny lobsters are food limited and hence, at least in theory, density dependent. If food (and often shelter space) is assumed to be limited in the pristine lobster population and if food quantity and quality remain fairly constant, then lobsters with low stock density, caused by decades of intensive fishing, could have increased rates of growth and egg production owing to excess food (Pollock et al., 1991).

Fig. 7.7 Comparison of observed and estimated catches of spiny lobster (1935/1995), using an ARIMA (0,1,1) model (from Baisre, unpubl.).

The Cuban Spiny Lobster Fishery

149

However, at this moment, there is no scientific evidence for determining whether density-independent factors, acting on planktonic larvae in oceanic waters of the Caribbean Sea, are more important than density-dependent factors acting on juveniles in nursery grounds, in determining levels of recruitment into the Cuban fishery.

References Aiken, D.E. (1980) Molting and growth. In The Biology and Management of Lobsters, Vol. I., Physiology and Behavior (Ed. by J.S. Cobb and B.F Phillips), pp. 91±147. Academic Press, New York, USA. Aiken, K. (1983) Further investigations of the spiny lobster fishery of Jamaica. FAO Fish. Rep., 278 (Suppl.), 177±91. Alfonso, L., FrõÂ as, M.P., Campos A. & Baisre, J.A. (1991). DistribucioÂn y abundancia de larvas de la langosta Panulirus argus en aguas alrededor de Cuba. Rev. Inv. Mar., 12(1±3), 5±19. Anon. (1981) Environmental impact statement and regulatory analysis for spiny lobster in the Gulf of Mexico and South Atlantic Fishery Management Councils, January 1981. BaÂez, M., DõÂ az E., Brito, R. & Cruz, R. (1991) Edad y crecimiento de la langosta Panulirus argus (Latreille) en la plataforma suroccidental de Cuba. Rev. Inv. Mar., 12(1±3), 193±201. Baisre, J.A. (1976) DistribucioÂn de las larvas de Panulirus argus y Scyllarus americanus (Crustacea, Decapoda) en aguas alrededor de Cuba. Rev. Inv. Inst. Nac. Pesca, 2(3), 277±97. Baisre, J.A. (1987) La pesca en Cuba: apuntes para su historia. IV. La pesca desde 1902 hasta 1952. Etapa de al seudorepuÂblica. Mar y Pesca, 265, 34±9. Baisre, J.A. & PaÂez J. (1981) Los recursos pesqueros del archipieÂlago cubano. Estudios WECAF, 8, 79 pp. Baisre, J.A., Blanco, W., Alvarez, I. & RuõÂ z de Quevedo, M.E. (1978) DistribucioÂn y abundancia relativa de las larvas de langosta (Panulirus argus) en el Mar Caribe y Bahamas. Rev. Cub. Inv. Pesq., 3(1), 1±20. Baisre J.A., PeÂrez, A., ObregoÂn, M.H. & Cruz, R. (1983) Regulation of fishing effort in Cuban shelf fisheries the case studies of shrimp, lane and spiny lobster fisheries. FAO Fish. Rep., 289 (Suppl. 3), 365±90. Beverton, R.J.H. & Holt, S.J. (1956) A review of methods for estimating mortality rates in exploited fish population with special reference to sources of bias in catch sampling. Rapp. P. V. ReÂun. Cons. Int. Explor. Mer., 140, 67±83. Beverton, R.J.H. & Holt, S.J. (1957) On the dynamics of exploited fish population. Fish. Invest. (London) Ser. 2, 19, 1±533. Buesa, R.J. (1965) BiologõÂa de la langosta Panulirus argus Latreille 1804 (Crustacea, Decapoda, Reptantia) en Cuba. Inst. Nac. Pesca, Cuba, 230 pp. Buesa, R.J. (1972) La langosta espinosa Panulirus argus: su pesca y biologõÂ a en aguas cubanas. Cent. Inv. Pesq. Cuba, II ± ReunioÂn de Balance, pp. 29±78. Caddy, J.F. (1984) An alternative to equilibrium theory for fishery management. FAO Fish.Rep., 289 (Suppl. 2), 173±214. Caddy, J.F. (1986) Stock assessment data-limited situations. The experience in tropical fisheries and its possible relevance to evaluation of invertebrate resources. Can Spec. Publ. Fish. Aquat. Sci., 92, 379±92. Caddy, J.F. (1990) Population dynamics, stock assessment and management opportunities for future research: a personal overview. Lobster Newslett., 3(2), 9±11.

150 Spiny Lobsters: Fisheries and Culture Caddy, J.F. (1991) Daily rings on squid statoliths: an opportunity to test standard population models? In Squid Age Determination Using Statoliths (Ed. by P.Jereb, S. Ragonese & S. von Boletzky), pp. 53±66. Proceedings of the International Workshop held in the Istituto di Tecnologia della Pesca e del Pescato (ITPP-CNR), Mazara del Vallo, Italy, 9±14 October 1989. NTRITPP. Special Publ., 1. Caddy, J.F. & Stamatapoulos, C. (1990) Mapping growth and mortality rates of crevice-dwelling organisms onto a perforated surface: the relevance of `cover' to the carrying capacity of natural and artificial habitats. Estuar. Coastal Shelf Sci., 31, 87±106. Capputi, N. & Brown, R.S. (1986) Relationship between indices of juvenile abundance and recruitment in the Western rock lobster (Panulirus argus) fishery. Can. J. Fish. Aquat. Sci., 43, 2131±9. Cobb, J.S. & Caddy, J.F. (1989) The population biology of decapods. In Marine Invertebrate Fisheries: Their Assessment and Management (Ed. by J.F. Caddy), pp. 327±74. John Wiley and Sons, New York, USA. Cruz, R. & LeoÂn, M.E. de (1991) DinaÂmica reproductiva de la langosta Panulirus argus en el archipieÂlago cubano. Rev. Inv. Mar., 12(1±3), 234±45. Cruz, R., Brito, R., DõÂ az, E. & Lalana, R. (1986) EcologõÂ a de la langosta (Panulirus argus) al SE de la Isla de al Juventud II. Patrones de movimiento. Rev. Inv. Mar., 3(3), 19±35. Cruz, R., Coyula, R. & RamõÂ rez, A.T. (1981) Crecimiento y mortalidad de la langosta espinosa (Panulirus argus) en la plataforma suroccidental de Cuba. Rev. Cub. Inv. Pesq., 6(4), 69±119. Cruz, R., LeoÂn, M.E. de, DõÂ az, E., Brito, E. & Puga, R. (1991a) Reclutamiento de puerulus de langosta (Panulirus argus) a la plataforma cubana Rev. Inv. Mar., 12(1±3), 66±75. Cruz, R., LeoÂn, M.E. de & Puga, R. (1995) Prediction of commercial catches of the spiny lobster Panulirus argus in the Gulf of BatabanoÂ, Cuba. Crustaceana, 68(2), 238±44. Cruz, R., Sotomayor, R., LeoÂn, M.E. de & Puga, R. (1991b) Impacto en el manejo de pesquerõÂ a de langosta en el archipieÂlago cubano. Rev. Inv. Mar., 12(1±3), 246±53. Csirke, J. & Caddy, J.F. (1983) Production modelling using mortality estimates. Canad. J. Fish. Aquat. Sci., 40, 43±51. Davis, G.E. (1975) Minimum size of mature spiny lobsters, Panulirus argus at Dry Tortugas Florida. Trans. Am. Fish. Soc., 104, 675±6. Davis, G.E. (1978) Management recommendations for juvenile spiny lobsters, Panulirus argus, in Biscayne National Monument, Florida. U.S. Natl. Park Series. S. Fla. Res. Center Rep., M-530, 32 pp. Eggleston, D.B., Lipcius, R.N., Miller, D.L. and Coba-Cetina, L. (1990) Shelter scaling regulates survival of juvenile Caribbean spiny lobster Panulirus argus. Mar. Ecol. Progr. Ser., 62, 79±88. Fogarty, M.J. (1989) Lobster recruitment process. Lobster Newslett., 2(2), 4, 5. Forcucci, D., Butler, M.J. & Hunt, J.H. (1994). Population dynamics of juvenile Caribbean spiny lobster, Panulirus argus, in Florida Bay, Florida. Bull. Mar. Sci., 54(3), 805±18. GarcõÂ a, C.F. (1919) Junta Nacional de Pesca, su Historia, Trabajos realizados en Ella. Impr. El Siglo XX, Havana, 83 pp. GarcõÂ a C., HernaÂndez, B., Baisre, J.A. & Cruz., R. (1991a) Factores climaÂticos en las pesquerõÂ as cubanas de langosta (P. argus): su relacioÂn con las migraciones masivas. Rev. Inv. Mar., 12(1±3), 131±9. GarcõÂ a, C., HernaÂndez , B., Chirino, A.L. & RodrõÂ guez, J.P. (1991b) Corrientes geostroÂficas alrededor de Cuba. Rev. Inv. Mar., 12(1±3), 29±38. GonzaÂlez G., Herrera, A., DõÂ az, E., Brito, R., Gotera, G. & Arrinda, C. (1991) BioecologõÂ a y conducta de la langosta (Panulirus argus, Latr.) en las zonas profundas del borde de la plataforma en la regioÂn suroccidental de Cuba. Rev. Inv. Mar., 12(1±3), 140±53. GonzaÂlez-Cano, J. (1991). Migration and refuge in the assessment and management of the spiny lobster Panulirus argus in the Mexican Caribbean. Ph.D. thesis, Imperial College, University of London, 448 pp.

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Gregory, D.R. & Labisky, R.F. (1981) Ovigerous setae as an indicator of reproductive maturity in the spiny lobster Panulirus argus (Latreille). Northeast Gulf Sci., 4, 109±13. Gregory, D.R., Labisky, R.F. & Combs, C.L. (1982) Reproductive dynamics of the spiny lobster, Panulirus argus in south Florida. Trans. Am. Fish. Soc., III(5), 575±84. Herrnkind, W.F. & Butler, M.J. (1986) Factors regulating postlarval settlement and juvenile microhabitat use by spiny lobster. Panulirus argus. Mar. Ecol. Prog. Ser., 34, 23±30. Hunt, J.H. & Lyons, W.G. (1986) Factors affecting growth and maturation of spiny lobsters, Panulirus argus, in the Florida Keys. Can. J. Fish Aquat. Sci., 43, 2243±7. Kanciruk, P. (1980) Ecology of juvenile and adult Panuliridae (spiny lobsters). In The Biology and Management of Lobsters, Vol. II (Ed. by J.S. Cobb & B.F. Phillips), pp. 59±96. Academic Press, New York, USA. Kanciruk, P. & Herrnkind, W.F. (1976) Autumnal reproduction in Panulirus argus at Bimini, Bahamas. Bull. Mar. Sci., 26, 417±32. Kanciruk, P. & Herrnkind, W.F. (1978) Mass migration of spiny lobster, Panulirus argus (Crustacea: Palinuridae): behavior and environmental correlates. Bull. Mar Sci., 28, 601±23. Labisky, R.F., Gregory, D.R. & Conti, J.A. (1980) Florida's spiny lobster fishery: an historical perspective. Fisheries 5(4), 28±57. LeoÂn, M.E. de, Cruz, R. & Puga, R. (1995) ActualizacioÂn de la edad y el crecimiento de la langosta espinosa (Panulirus argus). Rev. Cub. Inv. Pesq., 19(2), 3±8. Lyons, W.G., Barber, D.G., Foster, S.M., Kennedy, F.S. & Milano, G.R. (1981) The spiny lobster, Panulirus argus, in the middle and upper Florida Keys: population structure, seasonal dynamics and reproduction. Fla. Mar. Res. Publ., 38, 39 pp. MartõÂ nez, J.L. (1948) Cuba's spiny lobster industry. U.S. Fish. Wild. Serv. Fish, Leaflet No. 294, 1± 29. Marx, J.M. & Hernkind, W.F. (1985) Macroalgae (Rhodophyta: Laurencia spp.) as habitat for young juvenile spiny lobsters, Panulirus argus. Bill. Mar. Sci., 36, 423±31. Menzies, R.A. (1981) Biochemical population genetics and the spiny lobster larval recruitment problem: an update. Proc. Gulf Caribb. Fish. Inst., 33, 230±43. Morgan, G.R. (1980) Population dynamics and management of the Western rock lobster fishery. Mar. Policy, 4, 52±60. Munro, J.L. (!974) The biology, ecology, exploitation and management of Caribbean reef fisher. Part V. I. The biology, ecology and bioeconomics of Caribbean reef fishes. Crustaceans (spiny lobsters and cabs). Res. Rep. Zool. Dep. Rep. Univ. West Indies, 3, 57 pp. Paiva, M.P. & Costa, R.S. (1963) Tamanhos de femeas de langostas en reproducao nas aguas costeiras de CearaÂ. Arq. Estud. Biol. Mar. Univ. CearaÂ, 3, 53±6. Paiva, M.P. & Costa, R.S. (1964). Estudos de biologia da pesca da langostas no CearaÂ. Dados de 1963. Arg. Est. Biol. Mar. Univ. CearaÂ, 4, 45±70. Paiva, M.P. & Costa, R.S. (1965). Estudos de biologia da pesca de langostas no CearaÂ. Dados de 1964. Arg. Est. Biol. Mar. Univ. CearaÂ, 5, 127±50. Paiva, M.P. & Costa, R.S. (1966). Estudos de biologia da pesca de langostas no CearaÂ. Dados de 1965. Arg. Est. Biol. Mar. Univ. CearaÂ, 6, 167±93. Pauly, D. (1980) On the inter-relationship between natural mortality, growth parameters, and mean environmental temperature in 175 fish stocks. J. Cons. Int. Explor. Mer., 39, 175±92. Peacock, N.A. (1974). A study of the spiny lobster fishery of antigua and Barbuda. Proc. Gulf & Caribb. Fish. Inst., 26, 117±30. PeÂrez, A., Blanco, W. & FernaÂndez, R. (1978) CaÂlculo preliminar de curvas stock-reclutamiento para la langosta Panulirus argus en la zona A y sus efectos sobre la administracioÂn pesquera, 1 Foro Cient. Cen. Inv. Pesq., La Habana, Cuba, 19 pp. Phillips, B. & Cruz, R. (1990) Predicting the catch of the Cuban spiny lobster fishery. In II Congreso de Ciencias del Mar, 18±22 Junio de 1990, La Habana, Cuba., p. 160. (abstract only).

152 Spiny Lobsters: Fisheries and Culture Phillips, B.F., Palmer, M.J., Cruz, R. & Trendall, J.T. (1992) Estimating growth of the spiny lobsters Panulirus cygnus, Panulirus argus and Panulirus ornatus. Aust. J. Mar. Freswat. Res., 43(5), 1177±88. Pollock, D.E., Melville-Smith, R. & Cockroft, A.C. (1991) On the apparent resilience of spiny lobster stocks to exploitation. Lobster Newslett., 3(12), 1, 5. Puga, R., LeoÂn, M.E. de & Cruz, R. (1991) EvaluacioÂn de la pesquerõÂ a de langosta espinosa Panulirus argus en Cuba. Rev. Inv. Mar.,12(1±3), 286±92. Puga, R., LeoÂn, M.E. de & Cruz, R. (1996) Catchability for the main fishing methods in the Cuban fishery of the spiny lobster Panulirus argus (Latreille, 1804), and implications for management (Decapoda Palinuridea). Crustaceana, 69(6), 703±18. Ricker, W.E. (1954) Stock and recruitment, J. Fish Res. Bd. Can., 11, 559±623. Rikhter, V.A. & Efanov, V.N. (1976) On one of the approaches to estimation of natural mortality of fish population. ICNAF Res. Doc. 76/Vi/8, 12 pp. Salia S.B., Annala. J.H., McKoy, J.L. & Booth, J.D. (1979) Application of yield models to the New Zeland rock lobster fishery. N.Z. J. Mar. Freshwat. Res., 12, 1±2. Soares, C.N.C. & Cavalcante, P.P.L. (1985) Caribbean spiny lobsters (Panulirus argus) and smooth tail spiny lobster (Panulirus laevicauda) reproductive dynamics on the Brazilian Northeastern coast. FAO Fish. Rep., 327 (Suppl.), 200±17. Sutcliffe, W.H. (1952) Some observations of the breeding and migration of the Bermuda spiny lobster, Panulirus argus. Proc. Gulf Caribb. Fish. Inst., 4, 64±9. Waugh, G.T. (1980) Population dynamics of juvenile spiny lobster Panulirus argus, near Grand Bahama island. M.Sc. thesis, University of Miami, 195 pp. Witham, R., Ingle, R.M. & Sims, H.W. (1964) Notes on postlarvae of Panulirus argus. Q. J. Fla. Acad. Sci., 27, 289±97.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 8

The Atlantic Spiny Lobster Resources of Central America N M. EHRHARDT Division of Marine Biology and Fisheries, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Florida, USA

8.1

Introduction

The Caribbean spiny lobster, Panulirus argus, resource off the coast of Central America sustains one of the most economically important fisheries in the region. Exploitation of this resource has varied greatly throughout the history of the fisheries. Until the end of the 1950s spiny lobster exploitation was sporadic and circumstantial owing to difficulties at that time in accessing the few international markets available for lobster products from mostly isolated coastal communities. However, since the mid-1960s the spiny lobster has ranked as the second most important marine species landed in this region, being surpassed only by shrimp in both commercial value and weight. According to FAO Year Books of Fishery Statistics, during the period 1975±1989 over 19% of the total Caribbean spiny lobster landings originated from the Central American region. This percentage increased to about 22% in the period 1995±1997. The species is intensively exploited both by artisanal and industrial sectors over some 2885 km of coastline from Panama to Belize, generating over $120 million to fishermen and fleet owners. Fishing pressure on existing stocks in different regions of the continental shelf has been highly variable owing to widely varying opportunities concerning fishery development under significant political and economic changes historically observed in the bordering countries. In spite of the importance of this resource, spiny lobster demographics and their status of exploitation are still poorly known. In effect, very limited accounts of its life history and fisheries from this region have been published. Management of the resource has been unilaterally attempted in some countries by implementing regulations on minimum size, spawning season closures, forbidding landing of ripe (berried) females, etc., but an overriding lack of enforcement and illegal fishing have prevented an orderly utilization of the resource. In this report, recently revised landing statistics available from the countries in the region are used to describe spiny lobster fishery trends since the mid-1960s to 1997, and to draw some general exploitation patterns, which may be of value when considering pan-Caribbean hypotheses regarding spiny lobster population structures. 153

154 Spiny Lobsters: Fisheries and Culture 8.2.

Characteristics of the area

Central America has a territorial extension of about 525 000 km2 distributed among seven countries, of which Guatemala, Honduras and Nicaragua are the largest, followed by Panama, Costa Rica, El Salvador and Belize. El Salvador is the only country that does not have access to the Caribbean Sea, while Guatemala has a limited coastline of only 128 km on the Caribbean Sea. The coastline consists of a generally broad, gently undulating platform of medium to extremely low profile, and only in Honduras does the presence of the Cordillera Nombre de Dios towards the west contrast notably with the coastal lagoons and low-profile limestone platforms in the east. The continental shelf area extends over some 128 000 km2 but varies significantly among countries (Fig. 8.1). The largest shelf extensions are off Honduras and Nicaragua, with more than 51 800 and 57 000 km2, respectively. The continental shelf narrows considerably off Costa Rica (2340 km 2), Belize (3500 km2), and Panama (12 000 km2). Bays, lagoons, offshore islands, barrier reefs and several large atolls comprise the most important physical features of the environment in which fishing activities are conducted in this region. Precipitation (3000±6000 mm/year) is in the form of torrential downpours during the rainy season (June±December) with numerous rivers discharging considerable

Fig. 8.1 Geographical coastal profile and general direction of ocean currents in the Caribbean Sea.

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quantities of turbid, silt-laden water into broad coastal lagoons or directly into the sea. These sediments have inhibited coral growth and have created a silty, shallowbottom coastal environment, which is not suitable as a habitat for lobsters. The strong, persistent, easterly trade winds are instrumental to the character of oceanic currents in the western Caribbean Sea (Fig. 8.1) and to the general ecology of the region. During the 1990s, several category 4±5 hurricanes have impacted the Nicaragua±Belize coastal zone, resulting in heavy losses of human lives (Nicaragua and Honduras suffered 10 000 dead and 6000 people disappeared during Hurricane Mitch in October 1998), as well as significant destruction of coastal structures and of the marine environment. (Hurricane Joan in October 1988 generated massive destruction along the Nicaraguan coastal zone with loss of most lobster and shrimpprocessing plants in the port of Bluefields.) These winds are temporarily interrupted during the period December±February when the passage of a series of frontal storms sweeping down over the Gulf of Mexico constitutes the most significant meteorological phenomenon affecting the westernmost regions of the Caribbean Sea. Schumacher (1940) noted that the intensity of counterclockwise currents in the Gulf of Honduras (Fig. 8.1) was maximal during summer (June±August) months to almost non-existent during winter (December±February). This seasonal change in ocean current patterns coincides with peak summer spiny lobster spawning over wide ranges of the continental shelf off Central America and, therefore, they may have a significant role in the local retention of lobster larvae drifting in the ocean at that time. A second counterclockwise current is formed permanently off Costa Rica, Panama and Colombia as a result of the interaction of the Caribbean Current with the coast and continental shelf off Nicaragua and Honduras (Fig. 8.1). This counterclockwise current may contribute to the migration and recruitment of lobster upstream along the coasts of Costa Rica and Panama, and to recirculate the longerlived spiny lobster pueruli back to the Nicaraguan±Honduran shelf. Productivity in the Caribbean Sea is generally low, with an average primary production between 50 and 100 g C/m2/year and secondary production with average volumes ranging from 50 to 100 mg/m3. However, there is localized seasonal upwelling resulting from oceanic circulation at the edge of the Honduras±Nicaragua continental shelf, which make possible the existence of areas of higher primary production on the shelf. This characteristic makes this shelf one of the prime areas where the most abundant fishery resources in the western Caribbean Sea are found.

8.3

The fisheries

The spiny lobster fisheries off Central America did not show any significant development until the 1960s. There is little evidence to indicate that either aboriginal inhabitants or settlers during the colonial period made any attempt to utilize the spiny lobster, probably owing to a lack of effective means of catching them. The first recorded successful attempt to introduce traps as means of exploiting this resource

156 Spiny Lobsters: Fisheries and Culture occurred in Belize in 1921 (Craig, 1966). The traps, which were of a design similar to those traditionally used in the Maritime Provinces of Canada, underwent several modifications to adapt them to local conditions. In spite of its initial success, this fishery was abandoned in 1935, primarily because of a lack of demand in the unsettled market in the USA following the depression years. Until 1956, spiny lobster landings in the region did not exceed 130 metric tonnes (t) of tails per year; however, starting in 1957 and until 1960, a slight increase in the landings was observed in response to new market opportunities in the USA (Fig. 8.2). After 1963, expansion of fishing operations in Florida as a consequence of an increased demand for spiny lobster tails in the US market and the closing of US fishing operations in the Bahamas in 1975 opened new opportunities for spiny lobsters from the Central American fisheries. Total landings during the 1963±1974 period increased from 435 to 1457 t of tails. After 1974, the landings expanded even more rapidly, reaching a maximum of 3880 t of tails in 1978. Since that maximum, total landings have varied widely, with no clear trend, around an average of 3431 t of tails (Fig. 8.2). In general, if fisheries development trends are discounted, a cyclic pattern in the overall landings has been observed since 1969; that pattern is also reflected in landings at the national levels, thus suggesting the possibility of cyclic trends in population abundance which have become more conspicuously observed at higher levels of exploitation.

8.3.1

Panama

The Caribbean spiny lobster fishery of Panama is artisanal and catch statistics are not being systematically recorded in this fishery; however, landings are believed to be

Fig. 8.2

Total historic landings of Panulirus argus in the Central American region.

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less than 20 t/year and illegal fishing by other nations is suspected in this area. Reduced lobster stock abundance on the Panama continental shelf may be due to the absence of suitable habitat in the very narrow shelf, the `downstream' character of the stocks in this area and, more importantly, the lack of effective larval retention mechanisms within the Costa Rica±Panama gyre.

8.3.2

Costa Rica

The Caribbean spiny lobster fishery of Costa Rica is artisanal, mostly using dinghies or cayucos and open boats to about 10 m, powered with outboard motors. Lobsters are caught in 2.2  1.5 m, Z-shaped traps of local design, made of chicken wire, and equipped with two entrances in the ends. Trap configuration and construction respond to strong ocean currents prevailing over the very narrow continental shelf off Costa Rica. The fishery is localized in the area around the Port of Limon, with operations extending to the Rio Colorado region in the border with Nicaragua in years when increased spiny lobster abundance is observed. Landings are characterized by significant periods with very low catches followed by periods of greater abundance (Fig. 8.3). Results from limited tagging studies carried out in the region in 1970 demonstrated a significant unidirectional migration of spiny lobster from the Nicaraguan shelf into Costa Rica at rates of 4.9 nm/day (Ellis et al., 1971). An analysis of landing statistics found in Vidal et al. (1971) corresponding to Nicaragua and Costa Rica for the period 1962±1969, and which are believed to be unaffected by annual changes in fishing effort, indicates that years with increased

Fig. 8.3

Landings in Costa Rica (tonnes of tails).

158 Spiny Lobsters: Fisheries and Culture landings in Costa Rica are preceded by large landings in Nicaragua in the previous year, and vice versa (Fig. 8.4). In addition, a plot of landing anomalies (observation minus mean divided by standard deviation) for the Honduras fishery and those observed in Costa Rica (Fig. 8.5) shows approximately similar trends during the period 1980±1997. These findings imply a potential linkage in population biomass between the resources in the Nicaraguan±Honduran shelf and those immediately to

Fig. 8.4 Spiny lobster landing anomalies in Nicaragua and Costa Rica during the period 1962±1969. (Data from Vidal et al., 1971.)

Fig. 8.5 Spiny lobster landing anomalies in Honduras and Costa Rica during the period 1980±1997.

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the east on the Costa Rican shelf. The migratory character of the spiny lobster in this area is further corroborated by fishermen's reports expressing significant lobster runs, or corridas, in an easterly direction with a minor peak in September and a maximum peak in December and January. Consequently, the spiny lobster fishery of Costa Rica appears to be based on a non-resident (migratory) population that impacts significantly on the economy of coastal communities and the sustainability of a formal fishery in the years of low stock abundance.

8.3.3

Nicaragua

The spiny lobster fishery in Nicaragua is a year-round fishery, with important industrial and artisanal sectors. Commercial fishing for spiny lobsters was initiated in the southern regions of the shelf in 1958 when the first lobster-processing plant was established in the Great Island of the Corn Islands by US interests. At that time, one vessel and six local dories began deliveries to the processing plant and in 1961 six more lobster vessels from Key West, Florida, were incorporated into the fishery (NORAD/OLDEPESCA/FAO, 1990); by 1972 there were 55 lobster vessels operating in Nicaragua, with sizes ranging between 12 and 24 m LOA. In 1973, the industrial fishery expanded its operations to the northern regions of the shelf and the fleet increased to 96 vessels in 1975 and to 100 vessels in 1978 (NORAD/ OLDEPESCA/FAO, 1991). Most of these vessels were transformed shrimp trawlers that could carry out longer fishing trips to fairly inaccessible areas of the outer shelf. Landings during that period increased accordingly from 229 t of tails in 1972 to a peak of 1751 t of tails in 1978 (Fig. 8.6). However, for political reasons the USA

Fig. 8.6

Landings in Nicaragua and Honduras (t of tails).

160 Spiny Lobsters: Fisheries and Culture boycotted all Nicaraguan products during the period 1980±1990; consequently, during the period 1980±1981 most of the industrial fleet left Nicaragua. Under these circumstances 14 vessels remained in the fleet in 1982 and in 1987 the fleet consisted of only eight vessels. Lacking access to the US market, spiny lobster landings declined drastically to 558 t of tails in 1982 and to the lowest level of 248 t in 1987. However, with the advent of a democratically elected government in 1990, a programme for rebuilding the lobster fleet was initiated in 1991 and 34 new fishing units were incorporated to the fleet in the following years. In the period 1996±1999, four fleets with over 100 vessels and several hundreds of boats participated in the Nicaraguan fishery. These fleets are: (1) artisanal (traps and diving) fleets landing about 50% of the catch in 1996 and 1997; (2) the foreign industrial trap fleet; (3) the national industrial trap fleet; and (4) the national industrial dive fleet. With the fleet rebuilding programme, total spiny lobster landings reached a new maximum of 1961 t of tails in 1996 and landings in 1997 were about 1719 t. The new fleets have distinctly different operational characteristics. For example, vessels in the national industrial trap fleet operate an average of four strings of 400 traps daily for a total of 1600 traps, while vessels in the foreign industrial trap fleet operate a total of 3000 traps in strings of slightly over 900 traps serviced per day. The national fleet operates from 10 to 12 days per trip, while the foreign fleet operates up to 25 days per trip to make an efficient use of expensive temporal fishing licences sold by the government. Contrasting with the previous fleets, the industrial national dive fleet employs about 23±25 divers per vessel in fishing trips that may last for up to 20 days. In contrast with the industrial fleets, the artisanal fleet concentrates most of its fishing operations on fishing grounds in the Corn Islands area, in the southern range of the continental shelf where protected areas for artisanal lobster fishing have been created. Landings from the artisanal sector accounted for approximately 20% of total landings at the peak of the fishery in 1978. However, with the decrease in industrial fishing operations and the concomitant decrease in total landings, artisanal landings accounted for approximately 67% of total landings in 1983 and about 52% during the period 1984±1989. Spiny lobsters in the industrial fishery of Nicaragua are principally caught in wooden slat traps, although harvesting by diving is also common. For this purpose the larger industrial vessels are used in mothership fishing operations with divers catching lobsters from dinghies. The artisanal fisheries use traps, gill nets and diving to capture lobsters in the shallower areas of the shelf, mostly around the Corn Islands. The artisanal fisheries are significantly affected by ethnic rivalries resulting from an unequal economic opportunity to access the lobster resources by Black± Creole (their self-referential term) communities and the Miskito Indians (Meltzoff & Schull, 2000). The rich Corn Island lobster fisheries are sharply divided along ethnic lines between two catch methods, trapping and diving. No Black±Creoles dive for lobsters and no Miskito Indians are owners or captains of lobster-trapping boats. Diving has resulted in a large number of accidental deaths since 1990 when the government permitted this dangerous fishing practice after its ban for the same

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161

reason in 1984. Diving was allowed by the Government to increase landings that could generate more revenues from exports. Ehrhardt & CastanÄo (1995) assessed the status of exploitation of the Atlantic spiny lobster resources of Nicaragua. These authors found that the international fleets were 90.3% as efficient than the national fleets on a per-trap-day basis. This difference is due to the more intensive operations carried out during shorter trips of the national fleet. However, as the international fleets operate over longer trips, their efficiency on a per-trip basis is about 120% of that of the national fleet. They also found that catchability decreases significantly as fishing effort (measured in daysfishing standardized to the national trap fleet) increases. In effect, they reported a significant negative power function between the catchability coefficient (q) and daysfishing ( f ) given as q = 3247.96  f 2.04693. The connotation of this finding is that fishing effort units in the trap fleet compete among each other for fixed seasonal spiny lobster abundance. This effect is expected in passive (e.g. trap) gear fisheries and in dive fleets as each fishing unit (trap or divers) interacts more intensively among the units as their number increases. The fishing mortality rates estimated for the stock varied between 0.17 and 0.59 per year. Although some of the fishing mortality values were considered high in some years, in general those years corresponded to low stock abundance while catches remained stabilized. One important aspect of the results reported by the previous authors is the fact that spiny lobster abundance on the Nicaraguan shelf varied significantly in 4±5-year cycles, showing rather low levels of abundance between 1988 and 1991 followed by a significant increase in abundance during 1991 and 1992.

8.3.4

Honduras

The spiny lobster fishery of Honduras is the largest in the region since 1980, owing to the incorporation of Nicaraguan fleets that left that country after the political conflicts of 1979. The fishery is fundamentally industrial, with a very small fraction (<4%) of the landings reported from the artisanal sector. The vessels are either shrimp trawlers dually equipped to operate as shrimp trawlers and as lobster catchers, or lobster vessels specifically designed for that purpose. Wooden traps measuring 100  60  50 cm are commonly used by the fleet, although diving is also an important way of capturing spiny lobsters. The fleet is numerous and their activities began in the early 1960s with vessels incorporated from the USA. In 1974 there were over 135 vessels operating in the lobster fishery and by 1989 this fleet had exceeded 190 vessels (SECPLAN, 1991). Statistics of fleet size are not accurate and are usually contradictory because it is believed that a significant fraction of the industrial fleet from Nicaragua may have operated from Honduras after 1979. In addition, the number of fishing licences authorized by the government is usually much higher than the number of vessels reported fishing. Lobster fleets operate from

162 Spiny Lobsters: Fisheries and Culture the offshore Bay Islands (Utilla, Roatan and Guanaja) and from the continental ports of Cortes, La Ceiba, Tela, Trujillo, Castilla and Caratasca Bay. Spiny lobster landings in Honduras have been variously reported in national statistical leaflets; however, more than 95% of the landings are exported to the USA and, therefore, imports of fishery products to the USA have been used to correct the existing landing statistics. Spiny lobster landings were rather modest varying between 22 and 80 t of tails during the period 1962±1969 (Fig. 8.6). This trend changed significantly, starting in 1970 when landings in Honduras reached 480 t followed by a decrease during the period 1972±1974, which appears to be a common feature affecting spiny lobster landings in all other countries in the region. A very significant and sudden increase in spiny lobster landings was registered in Honduras between 1977 and 1978. The increasing trend continued throughout most of the 1980s reaching maximum levels of production in 1986 when 3231 t of tails were landed in Honduras. Steady landings between 2300 and 3000 t of tails characterize the period that continued until 1992. However, starting in 1993, a significant decrease in landings has been observed. The previous trends in landings and those observed in Nicaragua (Fig. 8.6) appear to be the consequence of landings from the Nicaraguan displaced fleets in Honduras and illegal fishing in Nicaragua during the Sandinista regime of the 1980s (Marin, 1986). Privatization of the lobster fishery in Nicaragua and reconstruction of the lobster fleets in that country after 1990 may have caused the drop in landings in Honduras after 1992. Therefore, a significant fraction of the spiny lobster landings in Honduras may have originated in the Nicaraguan shelf and it is likely that the fisheries of Nicaragua and Honduras exploit a common spiny lobster population resident of the wide continental shelf off both countries.

8.3.5

Belize

The commercial spiny lobster fishery of Belize is probably the oldest in the region, and trap-fishing experience gained in the 1920s and 1930s was the basis of the artisanal spiny lobster fishery in Cay Caulker (Craig, 1966). The artisanal and industrial fisheries of Belize use a variety of open boats and adapted vessels, and although trapping supplanted skin diving and hooking (the use of a J-shaped metal hook to extract lobsters from crevices), diving is instrumental in those areas where Cuban casitas (or artificial lobster-gathering devices) are used for gathering lobsters. Trap molesting by other fishermen, especially in areas close to more densely populated areas, has been an impediment to the development of an efficient trap fishery in Belize. This has led fishermen to set the traps strategically in no particular order and with no visible identification to avoid detection and poaching by competitors. Lobster fishing in Belize is mainly carried out along the extensive reef track from the border with Mexico in the north to the border with Guatemala in the south,

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163

including the offshore reefs of Lighthouse and Clover and Turneffe Island. According to official statistics from the Belize Department of Fisheries, landings from these areas were stable at about an average of 243 t of tails per year during the period 1958±1980 (Fig. 8.7). A period of slightly higher landings is observed from 1981 to 1985 when landing reached about 400 t of tails, followed by a period when landings varied around 300 t.

8.3.6

Management

In all countries except for Panama, there are management regulations to enhance production. Thus, closed seasons have generally been implemented in Belize during the period March±July to protect berried females at the time of peak spawning. A minimum size between 22 and 24 cm carapace length (CL) or 13.5 cm tail length has been adopted in most countries to avoid growth overfishing; however, this measure has been more realistically implemented to comply with minimum sizes required in the international markets. Berried females are illegal in the landings in Nicaragua; however, violations to this measure are common. In Honduras, fleet size was limited to 66 vessels in 1982 (Marin, 1986). This regulation was strictly implemented during the period 1983±1985 when 59±70 vessels operated in the fleet. In 1986, however, a total of 128 vessels was licensed by the government of Honduras and by 1988 this number had increased to 190 (SECPLAN, 1990). To secure the availability of spiny

Fig. 8.7

Landings in Belize (t of tails).

164 Spiny Lobsters: Fisheries and Culture lobster to the large artisanal fleet of the Corn Islands, Nicaragua established a 16-km area closed to vessels larger than 8 m LOA around the Big and Small Islands in that island group. In Nicaragua the maximum number of traps that could be operated by a vessel is 1600; however, there are no restrictions on the size of the traps or regulations on the dangerous practice of dive fishing for lobsters. In general, there is a low rate of compliance with fishery regulations due to a lack of strict enforcement and lack of understanding by the fishing industry on the gains to be obtained from the regulations.

8.4

Population structure

A significant issue regarding implementation of management policies on spiny lobster fisheries in the Caribbean is the general concept that units of stock are difficult to define. The reason for this difficulty is based on the fact that P. argus larvae may remain in the water column for 6±10 months and up to a year (Lewis, 1951; Lyons, 1980) before settling in a suitable juvenile habitat. This peculiar larval dynamic, when coupled with strong ocean currents dominating the general environment where these larvae are found, make it plausible that spiny lobster larval resources from far upstream may colonize regions far downstream ± thus the pan-Caribbean theory of spiny lobster populations. Under these circumstances, any management action in one country's fishery may have consequences on other regional fisheries. Several earlier studies suggest the likelihood that spiny lobster stocks may originate from a single gene pool in the Caribbean Sea (Menzies & Kerrigan, 1980; Lyons, 1981). Caribbean-wide genetic studies based on mitochondrial DNA performed during the 1990s provide more conclusive evidences that sustain the pan-Caribbean origin of spiny lobster. In effect, results from those studies show a consistent lack of major geographical differentiation in adults of P. argus (Silberman et al., 1994a) and a lack of seasonal variation in genetics of pueruli arriving in the Florida Keys (Silberman et al., 1994b). The lack of significant differences in the genetic structures among the adult spiny lobster population analysed is an indication of high levels of mixing, while the lack of seasonal variation at the larval stages in a downstream area (e.g. Florida) is an indication of the constancy of the mixing. Furthermore, Sarver et al. (1998) suggest that the Brazilian P. argus may be a subspecies (defined by the authors as Panulirus argus westonii), while Sarver et al. (1999) found occasional intrusion of Brazilian P. argus in Florida in the genetic material analysed for the spiny lobster population of Florida. These latter findings on genetic mixing are indicative of the extraordinary distances that these larvae may travel before settling, hence supporting the old argument that extreme long-distance colonization is possible in this species. The mid- and outer continental shelf of Nicaragua and Honduras has extended areas of corals and of corals and sand, which provide an adequate habitat to sustain

The Atlantic Spiny Lobster Resources of Central America

165

an important spiny lobster population. Mature spiny lobsters spawn throughout this area during a protracted season from May to September. Spiny lobster larvae are dispersed from the Nicaraguan±Honduran shelf in the prevailing ocean currents (Fig. 8.1). The counterclockwise ocean circulations in the Gulf of Honduras and off Costa Rica and Panama may be important mechanisms for local retention of larval stock. If in fact spiny lobster larvae are capable of remaining in the pelagic environment for extended periods until they find suitable substrate for settling, then spiny lobster larvae spawned off Nicaragua and Honduras are likely to reach the coasts of North America through the Yucatan Passage, the Loop Current of the Gulf of Mexico and/or the Gulf Stream along the Florida Keys. Seasonal gyres on the Pourtales Shelf off the Florida Keys may be important for spiny lobster larval advection from the Gulf Stream into the Lower Florida Keys (Yeung & McGowan, 1991). Powers & Bannerot (1984) report that at high levels of exploitation, observed fluctuations in landings in the Florida spiny lobster fishery corresponded to fluctuations in recruitment because landings consist primarily of new recruits. Similar to the Florida case, exploitation in the Nicaragua and Honduras lobster fisheries is very high and fluctuations in the combined landings from the two countries may, therefore, represent recruitment variability. Similar to the Florida spiny lobster fishery, the Nicaraguan±Honduran fishery has been fully developed since 1980. Anomalies (as previously defined) in landings for the 1980±1997 period were calculated to express possible trends in abundance in both regions and are plotted in Fig. 8.8. In general, the trends show strikingly similar overall patterns of abundance. In the Figure, only those anomalies corresponding to 1985, 1986 and 1992 in the Nicaragua±Honduras trend are above the values that

Fig. 8.8 Spiny lobster landing anomalies in Nicaragua and Honduras and similar deviations in spiny lobster landings in west Florida.

166 Spiny Lobsters: Fisheries and Culture would have matched the Florida trend, and 1989 and 1994 are years when the Florida anomalies are significantly above the Nicaragua±Honduras trend. In an attempt to corroborate whether the previous trends were regional in character, landing anomalies in the Brazil P. argus fishery were also calculated and compared with those previously estimated for the Nicaragua±Honduras fishery. The results are shown in Fig. 8.9, where it can be seen that the overall patterns of abundance in these two far separated regions have extraordinary similitude. The 1986 anomaly in the Nicaragua±Honduras trend is the only point significantly deviating from the anomaly patterns. From these results, one can conclude that during the period 1980±1997 a significantly common annual trend in relative abundance characterized the three regional fisheries with only a few significant region-specific deviations. These trends can be explained either if spiny lobster larvae in these three regions (Brazil, Central America and Florida) underwent recruitment processes with similar interannual relative spawning potential, larval retention rates, and mortality and growth rates or if, in effect, the contribution of larvae from the upstream sources is sufficiently large as to mimic a generalized regional recruitment variability that is observed in the downstream fisheries. Since the oceanographic regimes influencing each of the three areas are very different, it cannot be easily explained that three different, and supposedly separate, populations could generate similar patterns in stock abundance over a timespan of two decades. It is plausible, therefore, that the observed patterns in abundance anomalies among regions are the result of high levels of regional larval mixing ± a fact that is coincident with the results of genetic studies on P. argus. Under these considerations, deviations of anomaly trends in some years might be the result of significant local events affecting local larval recruitment.

Fig. 8.9 Spiny lobster landing anomalies in Nicaragua and Honduras and similar deviations in spiny lobster landings in Brazil.

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167

The previous arguments prompt the need to establish regional spiny lobster population dynamic studies in support of research regarding regional fishery management frameworks that could be implemented to enhance spiny lobster production in the Caribbean region of Central America.

References Craig, A.K. (1966) Geography of Fishing in British Honduras and Adjacent Coastal Waters. Louisiana State University Press, Baton Rouge, LA, USA, 143 pp. Ehrhardt, N.M. & CastanÄo, O. (1995) Assessment of the spiny lobster resources of the Atlantic coast of Nicaragua. Technical Report. Norwegian Agency for International Development (NORAD), May 1995. Ellis,R.W., Nishimoto, R.T., Wolf, F.M. & Hughes, W.M. (1971) A description of the fishing activity on the Atlantic coast of Costa Rica with observations of the resource available. FAO Regional Fisheries Development Project for Central America. Tech. Bull., 4(2), 39 pp. Lewis, J.B. (1951) The phyllosoma larvae of the spiny lobster, Panulirus argus. Bull. Mar. Sci., 1, 89±103. Lyons, W.G. (1980) The postlarval stage of scyllaridean lobsters. Fisheries, 5(4), 47±9. Lyons, W.G. (1981) Possible sources of Florida's spiny lobster population. Proc. Gulf. Caribb. Fish. Inst., 33, 253±66. Marin, M. (1986) Technical Report on the Status of the Shrimp and Lobster Resources of Honduras, 1986. Ministry of Natural Resources, General Directorate of Renewable Resources, Applied Research Unit, Tegucigalpa, Honduras, 39 pp. Meltzoff, S.K. & Schull, J. (2000) Ethnic struggle over land and lobster: Miskito Indians' cultural conservation. Cult. Agricult., Special Vol. 21, No. 3. Menzies, R.A. & Kerrigan, J.M. (1980) The larval recruitment problem of the spiny lobster. Fisheries, 5(4), 42±6. NORAD/OLDEPESCA/FAO (1990) Diagnostic of Fishing Activities in Nicaragua. Nicaraguan Fisheries Corporation, Ministry of Economy, Industry and Commerce, Nicaraguan Fund, and Secretary of Planning and Budget, 249 pp. NORAD/OLDEPESCA/FAO (1991) Synopsis of the Fisheries in Central America. Regional Fishery Management and Planning Project, 410 pp. Powers, J.E. & Bannerot, S.P. (1984) Assessment of Spiny Lobster Resources of the Gulf of Mexico and Southeastern United States. National Marine Fisheries Service, Southeast Fisheries Center, Miami, FL, USA, 25 pp. Sarver, S.K., Freshwater, D.W. & Walsh, P.J. (in press) The occurrence of the Brazilian sub-species of the spiny lobster (Panulirus argus westonii) in Florida waters. Fish. Bull. U.S. Sarver, S.K., Silberman, J.D. & Walsh, P.J. (1998) Mitochondrial DNA sequence evidence supports the existence of two subspecies or species of the Florida spiny lobster Panulirus argus (Latrielle). J. Crust. Biol., 118, 177±86. Schumacher, A. (1940) Monatskarten der Oberflachenstromungen un Nordatlanschen Ozean (5oS±50oN). Ann. Hydr. Marit. Meteorol., 71, 209. SECPLAN (1990) Diagnostic of the Fishery Sector in Honduras. Secretary of Planning, Coordination and Budget. Secretary of Natural Resources, Tegucigalpa, Honduras, 341 pp. Silberman, J.D., Sarver, S.K. & Walsh, P.J. (1994a) Mitochondrial DNA variation and population structure in the spiny lobster, Panulirus argus. Mar. Biol., 120, 601±8. Silberman, J.D., Sarver, S.K. & Walsh, P.J. (1994b) Mitochondrial DNA variation in seasonal cohorts of spiny lobster (Panulirus argus) postlarvae. Molec. Mar. Biol. Biotechnol., 3, 165±70.

168 Spiny Lobsters: Fisheries and Culture Vidal, J., Couve, A. & Lopez, M. (1971) Fishery resources of Costa Rica: assessment and projections. FAO Regional Fishery Development Project for Central America. Tech. Bull., 6(2), 99 pp. Yeung, C. & McGowan, M.S. (1991) Differences in inshore±offshore and vertical distribution of phyllosoma larvae of Panulirus, Scyllarus, Scyllarides in the Florida Keys in May±June, 1989. Bull. Mar. Sci., 49(3), 699±714.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 9

The Spiny Lobster Fisheries in Mexico

P. BRIONES-FOURZAÂN and E. LOZANO-AÂLVAREZ Universidad Nacional AutoÂnoma de MeÂxico, Instituto de Ciencias del Mar y LimnologõÂa, Unidad AcadeÂmica Puerto Morelos, Ap. Postal 1152, CancuÂn Q.R. 77500, MeÂxico

9.1

Spiny lobster species in Mexico: distribution and general characteristics

Spiny lobsters occur throughout most of the coasts of Mexico. From 1985 to 1997, the total spiny lobster catch has fluctuated around 2328 t, 50% of which has been exported, mainly to the USA. In 1997, spiny lobster production was 2552 t, of which 1697 t were exported, yielding an income of US $25.7 million (Anon., 1998), occupying the fourth place in value among fishing resources exported by Mexico. Although there are seven species of spiny lobsters (Palinuridae) in Mexico (Gracia & Kensler, 1980), only four are of commercial importance. Together, Panulirus interruptus and P. argus constituted, on average, 91% of the national yearly catch during the period 1985±1997 (Anon., 1998), and P. inflatus and P. gracilis accounted for the rest of the production. The three species that are not of commercial importance are P. penicillatus, which occurs on certain islands on the Pacific (Briones-FourzaÂn & Lozano-AÂlvarez, 1982; Flores-CampanÄa & PeÂrez-GonzaÂlez, 1991); P. guttatus, a small, obligate reef-dweller species occurring on the Caribbean coast (Briones-FourzaÂn, 1995b), which accounts for about 5% of the lobster production in Quintana Roo (Padilla-Ramos & Briones-FourzaÂn, 1997), and P. laevicauda, also from the Caribbean coast, of which only a few specimens are sporadically reported in the commercial catch. Panulirus interruptus occurs along the west coast of the Baja California peninsula (Chapa, 1964) (Fig. 9.1b). Small populations of this species are also found in certain parts of the west coast of the Gulf of California (Ayala et al., 1988). Panulirus inflatus is endemic to Mexico, and coexists with P. gracilis from BahõÂ a Magdalena (Baja California Sur), throughout the Gulf of California and the west coast of Mexico to the Gulf of Tehuantepec (Holthuis & Villalobos, 1961; Chapa, 1964; Briones-FourzaÂn & Lozano-AÂlvarez, 1992). Panulirus argus occurs on the Caribbean coast of Mexico, along the coast of the state of YucataÂn, and in coral formations in front of the states of Campeche, Tamaulipas and Veracruz, in the Gulf of Mexico (Briones-FourzaÂn, 1995a) (Fig. 9.1a), but 98% of the catch of P. argus is obtained in the states of Quintana Roo and YucataÂn (Fig. 9.1c). 169

170 Spiny Lobsters: Fisheries and Culture

Fig. 9.1 (a) Map of Mexico, showing only the coastal states. (b) The Baja California peninsula, site of the fishery for Panulirus interruptus. Numbers in circles indicate zones of stepped closures; zone 5 encompasses from Sonora to Chiapas. (c) The YucataÂn peninsula, site of the fishery for Panulirus argus.

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171

History of the fisheries

Between 1950 and 1992, spiny lobsters were among a group of marine species whose exploitation was reserved for fishing co-operatives. A fishing co-operative is an organization that entitles its members to exploit valuable fishing resources collectively, through the utilization of common, non-negotiable (and hence, of national character) property (Medina, 1982). In 1992, the Federal Law for Fisheries was changed. Exclusivity to former reserved species was derogued and their exploitation became subject to a new scheme based on concessions and permits in defined areas to which, in theory, any proponents could apply. Up to now, concessions for exploiting spiny lobsters, lasting from 5 to 20 years, have been granted to those fishing co-operatives already existing that proved to have sufficient technical, organizational and economic capacity. Some co-operatives that did not fully meet the requisites have been granted permits for up to 4 years. The oldest and most important spiny lobster fishery in Mexico, dating from the end of the nineteenth century, is the P. interruptus fishery in Baja California, for which Ayala et al. (1988), Vega & Lluch-Cota (1992) and Vega et al. (1996), have provided a thorough history. The fishery for P. inflatus and P. gracilis is not fully developed. Most of the cooperatives that fish for them along the Pacific coast of Mexico also exploit other resources, and often spiny lobsters are only an incidental catch. In the Caribbean coast of Mexico, the fishery for P. argus started around 1955, when the first fishing co-operatives were founded in the state of Quintana Roo (Miller, 1982). In the state of YucataÂn, the fishery started later, during the 1970s. However, whereas in Quintana Roo spiny lobster is the target species for most of the co-operatives, in YucataÂn the fisheries are more diversified. This is due to the width of the continental shelf of YucataÂn, in contrast to the shelf of Quintana Roo which is narrow. In the early days of the fishery, wooden sailboats were used and lobsters were caught with a long-handled bully net, operated from the boat (Fuentes, 1988). During the 1960s, `ink-pot' lobster traps, SCUBA (self-contained underwater breathing apparatus) and `hookah' diving, as well as artificial shelters, called casitas (Chapter 23), were introduced into the fishery (Miller, 1982). During the 1980s, inkpot traps were replaced by rectangular, galvanized wire traps.

9.3

Fishing regulations

Fishing regulations, which had remained basically unchanged between 1960 and 1990, have undergone a number of modifications throughout the 1990s. However, the main regulations still include a closed season, a minimum legal size (MLS) and a prohibition on the catching of egg-bearing females. Table 9.1 summarizes the closures and MLS of all the lobster species in Mexico as of 1998. Some regulations

172 Spiny Lobsters: Fisheries and Culture Table 9.1

Summary of fishing regulations for the spiny lobster species in Mexico

Lobster species

Fishing zonea

Closed season

Panulirus interruptus

1 2

16 Feb.±15 Sept. 1 Mar.±30 Sept.

3 4 3 4

1 1 1 1

5 5 Gulf of Mexico and Mexican Caribbean

1 July±30 Oct. 1 July±30 Oct. 1 Mar.±30 June

P. inflatus, P. gracilis

P. penicillatus P. argus, P. guttatus, P. laevicauda

Apr.±30 June±15 Apr.±30 June±15

Oct. Nov. Oct. Nov.

MLS 82.5 mm CL

82.5 mm CL 75.0 mm CLb 82.5 mm CL 135 mm AL

a

Fishing zones 1±5 on the Pacific coast are indicated in Fig. 9.1b. Only from MichoacaÂn to Chiapas. MLS, minimum legal size; CL, carapace length; AL, abdominal length. Source: Anon., 1998. b

apply even to lobster species which are not commercially exploited, such as P. penicillatus and P. laevicauda. Until 1993, the closure for P. interruptus was the same throughout the western coast of the Baja California Peninsula. However, because of latitudinal variations in the reproductive cycle of P. interruptus along this coast, the fishery is now managed through stepped closures in four zones (Fig. 9.1b, Table 9.1). The MSL of P. interruptus, established at 82.5 mm carapace length (CL) since 1962, applies throughout the fishery. The closed season for P. inflatus and P. gracilis is currently stepped in three zones along their range of distribution (Table 9.1). The MLS for both species is 82.5 mm CL in zones 3, 4, and the portion of zone 5 from Sonora to Colima, but has been reduced to 75.0 mm CL from MichoacaÂn to Chiapas since 1993 (Fig. 9.1a). The closed season for P. argus underwent a number of changes during the 1980s, but since 1989 it has been set from 1 March to 30 June. Panulirus argus has historically been commercialized as lobster tails, and hence the MLS is set as abdominal length (AL). Between 1979 and 1998, MLS for P. argus was 145 mm AL, except for the bays of AscensioÂn and EspõÂ ritu Santo (Fig. 9.1c), which had a special MLS of 135 mm AL. In 1998, the MLS was unified as 135 mm AL for the whole fishery, mainly because of the higher market value of lobsters with 135±145 mm AL. Although the spotted spiny lobster, P. guttatus, is caught in very small quantities and is of a much smaller size, it has the same MLS and closure as P. argus (Table 9.1). Exportation of live lobsters, which for a long time was prohibited to protect the national lobster processing industry as a source for jobs, is currently not only permitted, but encouraged, owing to the great demand for live lobsters in some foreign

The Spiny Lobster Fisheries in Mexico

173

markets, with more attractive prices for the fishermen. Exportation of live lobsters began in 1996 in Baja California (P. interruptus) and Quintana Roo (P. argus).

9.4 9.4.1

The spiny lobster fisheries of the Pacific coast Biological features of Panulirus interruptus, P. inflatus and P. gracilis

Panulirus interruptus occurs in rocky areas from the low intertidal zone to depths of around 100 m (Lindberg, 1955; Vega et al., 1996). Females have one brood per year. Females breed earlier in the northern areas (June), than in the central (July) and southern parts (August) of Baja California (Lindberg, 1955; Pineda et al., 1981; Ayala, 1983; Vega et al., 1996). Fecundity also follows a latitudinal trend, with females producing fewer eggs per brood in the north than in the south of the peninsula (Pineda et al., 1981). Breeding and hatching occur in shallow areas (<20 m), into which adults move in the spring. Lobsters return to deeper waters in the autumn (Lindberg, 1955; Mitchell et al., 1969; Ayala et al., 1988). The duration of the larval period was estimated by Johnson (1956) as 7.75 months. In BahõÂ a Tortugas, Baja California Sur, pueruli settled on artificial collectors for most of the year, but with a major peak in autumn (September±October) and a minor peak in spring (March±June; GuzmaÂn del Proo et al., 1996). Recently settled pueruli and small juveniles commonly inhabit 0±4-m deep rocky habitats having dense plant cover (Engle, 1979; Ayala & ChaÂvez, 1985), particularly the surf grass Phyllospadix torreyi. Juveniles and subadults are highly gregarious (Parker, 1972; Zimmer-Faust & Spanier, 1987). Growth studies on P. interruptus in Mexico have been performed using a number of methods. Ayala (1976) estimated age at sexual maturity (65 mm CL) as 3 years for males and 5 for females, but the estimates of GuzmaÂn del Proo & Pineda (1992) are, respectively, 4.5 and 6 years. Similarly, the age of males and females at MLS (82.5 mm CL) was estimated by Ayala (1976) at 4 and 7 years, and at 6.5 and 8.5 years by GuzmaÂn del Proo & Pineda (1992). Studies on the biology of P. inflatus and P. gracilis in Mexico are scarce, owing to their low importance compared with P. interruptus or P. argus. Both species occur from the sublittoral zone to depths of 40 m (Weinborn, 1977; Briones-FourzaÂn et al., 1981). Whereas P. inflatus is restricted to rocky habitats with relatively clear waters, P. gracilis has a tolerance for a wider range of turbidity and inhabits both rocky and gravel±sand bottoms (Gracia & Kensler, 1980; Briones-FourzaÂn & Lozano-AÂlvarez, 1992). Size of females at first maturity is small: 45.6 mm CL in P. inflatus (Gracia, 1985) and 47.5 mm CL in P. gracilis (Weinborn, 1977). Although both species breed throughout the year, the time and number of broods per year is size dependent (Briones-FourzaÂn & Lozano-AÂlvarez, 1992). Repetitive breeding is common, and large females can have up to five broods per year, with an estimated incubation period of about 30 days (Briones-FourzaÂn & Lozano-AÂlvarez, 1992). Brood size of

174 Spiny Lobsters: Fisheries and Culture P. inflatus was estimated between 69 100 and 570 750 eggs for females 45.6±86.4 mm CL (Gracia, 1985), and of P. gracilis between 241 420 and 465 500 eggs for females 54.0±106.1 mm CL (FernaÂndez-LomelõÂ n, 1992). Pueruli of P. inflatus and P. gracilis have been found in the stomach contents of the catfish Netuma platypogon, and the labrids Umbrina xanti and Larimus acclivis (Gracia & Lozano-AÂlvarez, 1980). Juvenile and adult predators include lutjanids (snappers), serranids (groupers), and octopuses. In the state of Guerrero (Fig. 9.1a), density of P. inflatus throughout the year varied between 4.1 and 86.2 lobsters/ha and of P. gracilis between 6.6 and 43.1 lobsters/ha (Lozano-AÂlvarez et al., 1982). Molluscs, crustaceans and polychaetes were the most abundant food items in both species (Lozano-AÂlvarez & Aramoni-Serrano, 1996). Growth of both species is rapid, reaching 65 mm CL (size at which 30% of females are reproductive; BrionesFourzaÂn & Lozano-AÂlvarez, 1992), at approximately 2 years after hatching, allowing 7 months as the duration of the larval period (Johnson & Knight, 1966). 9.4.2

Fishing methods

Panulirus interruptus is caught with traps. The traps are rectangular and covered with galvanized, plastic-sheathed wire mesh. Wooden traps and occasionally tangle nets are used only in the southernmost part of the Baja California Peninsula (Vega et al., 1996). Traps are baited with fish or molluscs. Fibreglass boats now in use measure 5±7 m long and are propelled by outboard, 40±65 HP (i.e. 29.8±48.5 kW), motors. In the north and centre of the Peninsula, boats are equipped with hydraulic winches. Fishermen keep the lobsters alive for a few days in special floating wooden containers called recibas (Chapa, 1964; Ayala et al., 1988). Live lobsters are then transported to reception centres distributed along the coast, where most of them are steam-cooked whole, packed in boxes and frozen. A small proportion is processed as frozen lobster tails. Most of the catch is exported to the USA, and a part is consumed locally or in important cities within Mexico. More recently, a fraction of the catch is exported live, particularly to Asian countries. Panulirus inflatus and P. gracilis are caught using traps similar to those used for P. interruptus, as well as tangle nets (PeÂrez-GonzaÂlez et al., 1992a). The traps are more effective for catching P. inflatus, whereas P. gracilis is more abundant in catches obtained with nets. In the state of Nayarit and further south, SCUBA, hookah or skin diving is also used. In Guerrero, diving is the only fishing method used, and efforts to introduce traps or nets into the fishery have not been successful (LozanoAÂlvarez & Briones-FourzaÂn, 1982). Whole lobsters are boiled and sold locally. 9.4.3

Catch and CPUE trends

Figure 9.2 shows the production of spiny lobster from the Pacific coast from 1955 to 1997. Analysis of the production by species is difficult, because they are not

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separated in the fisheries records. However, from the 1950s through to the 1970s, most of the national production was obtained from this coast, and virtually all of it was P. interruptus, because production from the rest of the Pacific coast was negligible in this period (SecretarõÂ a de Pesca, 1987). In the 1970s and 1980s, production from the Pacific coast fluctuated around 1300 t, except for the period 1980±1982, when a peak in catches occurred. Catches of P. inflatus and P. gracilis during the same period also contributed to the peak in catches. P. interruptus made up an average of 54.9% of the national yearly catch between 1985 and 1997 (Anon., 1998), and a mean of 87.5% of the catch from the Mexican Pacific coast during the same period (Fig. 9.3). In Baja California, 26 fishing cooperatives exploit P. interruptus. However, 10 co-operatives operating on the central region of the Peninsula, from Punta Abreojos to Isla Cedros (Fig. 9.1b), produce around 80% of the total catch of this species (Vega et al., 1996). In this region, newly recruited lobsters (82.5±90.0 mm CL) represent around 70±75% of the catch (Vega et al., 1996). Fishermen follow the inshore±offshore lobster movements with their traps. Catch is highest during the first 2 months after the fishing season opens and declines over the rest of the season, particularly in the most productive zones (Pineda & DõÂ az de LeoÂn, 1976; Ayala et al., 1988). Catch per unit effort (CPUE) may fluctuate between 0.37 and 0.55 kg per trap per night (Vega et al., 1996). Females are usually more abundant than males in the catch.

Fig. 9.2 Total spiny lobster production of Mexico (solid circles), from 1955 to 1997, with contributions from the Pacific coast (open circles) and from the YucataÂn peninsula (solid triangles). Sources: SecretarõÂ a de Pesca (1987); Anon. (1998).

176 Spiny Lobsters: Fisheries and Culture

Fig. 9.3 Percentage of the annual catch of spiny lobster (live weight) of the Pacific coast (1985±1997) contributed by the Baja California peninsula (grey bars) and by the rest of the Pacific coast (black bars). Numbers above bars represent total catch for that year. Source: Anon. (1998).

Phillips et al. (1994) found that catches of P. interruptus in Baja California were higher 4 years after El NinÄo Southern Oscillation (ENSO) episodes that cause high sea levels and a strong poleward flow. Vega & Lluch-Cota (1992) found evidence of a relationship between sea surface temperature and lobster catch. By incorporating the thermal anomalies of surface waters along the central region of Baja California to a yield model, Vega et al. (in press) suggested that the stock of P. interruptus is still above the optimum level, i.e. the biomass is above the level of maximum productivity. However, after incorporating the uncertainty in the processes of evaluation and management, they found that an increase of 20% above the current mean catch would produce a decline in the biomass below the maximum exceeding yield, and advised against a catch of over 1239 t/year for this region. Between 1985 and 1997, the catch of P. inflatus and P. gracilis has fluctuated between a maximum of 295 t in 1986 and a minimum of 54 t in 1993, and has accounted for 5±18% of the catch from the Pacific coast (Fig. 9.3). During this period, the state of Sinaloa produced 24.6% of the combined catch of both species, followed by Guerrero (23.4%), Jalisco (16.4%) and MichoacaÂn (16.0%), although with ample yearly fluctuations. In Guerrero, males of both P. inflatus and P. gracilis

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are more abundant than females in the catch (Weinborn, 1977; Briones-FourzaÂn et al., 1981; Lozano-AÂlvarez et al., 1982), whereas in Sinaloa it is the other way around (PeÂrez-GonzaÂlez et al., 1992a). Depending on the year, the largest catches are obtained between November and December, and again between March and May. CPUE for southern Sinaloa fluctuates between 1 and 14 kg lobster/boat (PeÂrezGonzaÂlez et al. 1992b; Flores-CampanÄa et al., 1993). No stock assessments have been made for this fishery.

9.5 9.5.1

The Panulirus argus fisheries of the Yucatan Peninsula Biological features of Panulirus argus

Panulirus argus is the main fishing resource in the state of Quintana Roo (Caribbean coast) and is also largely fished in the state of YucataÂn (Fig. 9.1c). Studies on the biology and ecology of this species abound, but those produced in Mexico are still relatively scarce. In Mexican waters, P. argus occurs from sublittoral areas to depths of about 60 m (Briones-FourzaÂn, 1995a). Reproduction occurs during most of the year, with a peak in spring (March±May) and a second peak in autumn (August± October) (Fuentes et al., 1991; GonzaÂlez-Cano, 1991; RamõÂ rez, 1997). Reproductive activity is lowest during the winter. Brood size was estimated between 120 000 and 1 550 000 eggs in females 76±138 mm CL (Fonseca-Larios & Briones-FourzaÂn, 1998). In Quintana Roo, the smallest reported ovigerous female measured 133 mm AL (approx. 74.8 mm CL) (RamõÂ rez, 1997). The duration of the larval period has been estimated from 6 to 11 months (Lewis, 1951; Sims & Ingle, 1966; Lyons, 1980). Pueruli settle on shallow areas with seagrass or algal beds, particularly rhodophytes (Marx & Herrnkind, 1985). Pueruli settlement on artificial collectors (GutieÂrrez et al., 1992) has been monitored since 1987 in BahõÂ a de la AscensioÂn (Fig. 9.2c) and since 1990 in Puerto Morelos (BrionesFourzaÂn, 1993, 1994). Pueruli enter the coast all year round, but with a high temporal and spatial variability, although during most years there is a peak in autumn (September±November) (Briones-FourzaÂn, 1994). Juveniles of P. argus inhabit shallow bays and reef lagoons along the Quintana Roo coast, and the shallow vegetated areas of the YucataÂn shelf. In areas where shelter is apparently limited, artificial shelters called casitas attract large numbers of juvenile and subadult lobsters, and are the basis of an important local fishery (Chapter 23). Growth of juveniles in these areas is rapid, reaching 74 mm CL at 1.7 years after settling (Lozano-AÂlvarez et al., 1991b). When juveniles approach sexual maturity, they move accross the coral reefs to deeper waters, where reproduction takes place (Lozano-AÂlvarez et al., 1991a, 1993). In addition to these ontogentic migrations, a seasonal massive migration occurs in areas close to Isla Mujeres and Isla Contoy during late autumn or in the winter (Ramos, 1974; GonzaÂlez-Cano,

178 Spiny Lobsters: Fisheries and Culture 1991). Whether this migration also takes place in other parts of the Caribbean coast of Mexico remains controversial.

9.5.2

Fishing methods

In the state of YucataÂn, the spiny lobster fishery is relatively new and is not yet fully developed (Fuentes et al., 1991). Lobsters are fished in this state mainly by `hookah' or skin diving (Seijo et al., 1994), although in the early 1990s casitas were introduced in several areas (RõÂ os et al., 1995). Conversely, in the state of Quintana Roo, particularly around Isla Mujeres (Fig. 9.1c), fishing methods include lobster traps, SCUBA, hookah and skin diving (Fuentes, 1988). In addition, lobster tangle nets are used near to Isla Contoy during the winter migration. Casitas have been used in the bays of AscensioÂn and EspõÂ ritu Santo (Fig. 9.1c) since the late 1960s, and in more recent years their use has expanded to other parts of the coast. Lobsters that occupy the casitas are extracted with a gaff, a hoop net or a seine net. Further south, the only fishing method used is skin diving (Lozano-AÂlvarez, 1994; Sosa-Cordero et al., 1996). Currently, 19 co-operatives in Quintana Roo and 16 in YucataÂn are involved in the lobster fishery. The target species for fishermen from Quintana Roo is lobsters, but in northern and western YucataÂn, fishermen traditionally allocate their fishing effort to a large number of species during the year. They shift their target species even during the lobster fishing season (Seijo et al., 1991, 1994; RõÂ os et al., 1995). Bad weather and corresponding water turbidity limit diving for lobsters in this area (Fuentes et al., 1991; Salas et al., 1991). Some co-operatives in Isla Mujeres that use traps have equipped their boats with navigational devices and winches to haul the traps. The rest of the fishery is performed by means of open fibreglass boats, 5±8 m long, with outboard motors. Most of the catch is commercialized as lobster tails. Lobster tails are removed either on board the vessels or immediately after being landed, and frozen fresh (LozanoAÂlvarez et al., 1991b). Most of the lobster tails are sold locally and the rest is exported to the USA. Recently, commercialization of live lobsters began. Cooperatives in the areas of Isla Mujeres and BahõÂ a de la AscensioÂn are the main producers of live lobsters, which are taken in traps or from casitas. Live lobsters are kept in floating containers called recibas for a maximum of 5 days to minimize mortality. The buyers are then responsible for shipping the live lobsters, mainly to Asian markets.

9.5.3

Catch and CPUE trends

The states of Quintana Roo and YucataÂn produced 98.1% of the P. argus catch in the period 1985±1997. A strong decline in the catch (Fig.9.2) occurred in 1989/90,

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after Hurricane Gilbert struck the coast of Quintana Roo and crossed the YucataÂn Peninsula in September 1988, destroying a large amount of fishing gear and possibly disrupting the population structure of lobsters (Lozano-AÂlvarez, 1994). After this decline, the total catch of P. argus has shown a zigzag pattern (Fig. 9.1), caused mostly by variations in the catch of YucataÂn (Fig. 9.4), whereas in Quintana Roo variations in the catch have been smaller, but with levels inferior to those prior to 1989. The mean fishing depth for the various fishing methods fluctuates from 3 m for casitas to 35 m for traps. Size composition of the catch also varies according to fishing method used or to the fishing area surveyed (Lozano-AÂlvarez et al., 1991a, b, 1993; Seijo et al., 1991; Lozano-AÂlvarez, 1994). The use of so many fishing methods in the P. argus fishery has precluded the standardization of effort and, hence, the reliable estimation of CPUE. Because of this difficulty, many authors have used the nominal effort (i.e. number of fishermen or number of boats) to at least have a gross estimation of the CPUE. Arceo (1991) and Arceo & Seijo (1991) analysed the fishing effort exerted with different fishing gear, by considering effective fishing time, number of crew members, number of trap-lifts (where applicable) and fishing depth. Their results showed that, in the case of nets and traps, effective fishing time and depth were the most significant variables. In the casita fishery, the most important variables were effective fishing time and number of crew members. According to GonzaÂlez-Cano (1991), the fishery around Isla Mujeres reached an extreme crowding state during the late 1980s, with a concurrent increase in rent

Fig. 9.4 Catch of Panulirus argus from the states of Quintana Roo (solid circles) and YucataÂn (open circles) during the period 1985±1997. Source: Anon. (1998).

180 Spiny Lobsters: Fisheries and Culture dissipation. A main problem in this fishery is the technological interference caused by the use of disparate fishing methods on the same fishing grounds. More recently, GonzaÂlez-Cano et al. (in press) have suggested that, for north-eastern Quintana Roo, the optimum nominal effort producing the best CPUE should be about 75% of the amount reached in the 1986/87 fishing season. Seijo et al. (1991) conducted a comparative bioeconomic analysis of the P. argus fishery in seven fishing ports of the YucataÂn Peninsula. The highest fishing yield was obtained by traps, but with higher total costs. Tangle nets resulted in similar fishing yields with lower operating costs, but these nets are used only during the winter migration. Diving generated the lowest fishing yields, which varied from place to place. The highest benefits, in terms of costs and revenues, were obtained with the use of casitas (Arceo, 1991; Seijo et al., 1991). Because fishermen are aware of this, the use of casitas has recently expanded in northern Quintana Roo and YucataÂn, but there have been no controlled assessments of the effects of this expansion.

9.5.4

Stock assessments

During the 1990s, the stock of P. argus has been assessed by means of different methods in some particular areas of the fishery. In YucataÂn, four different models have been applied based on catch, nominal effort (number of boats), and lengthfrequency analysis. Despite the disparate results obtained through these models, they all seem to concur in that the fishery in YucataÂn is still below the maximum levels of exploitation (RõÂ os & Zetina, 1997; Zetina & RõÂ os, 1997). However, the models employed do not take into account the distribution of effort, and in some areas of YucataÂn the fishery has reached a rent dissipation, so these authors strongly recommend that the fishing effort be regulated in the future. In Quintana Roo, stock assessments have been conducted for the north-eastern area (around Isla Mujeres), BahõÂ a de la AscensioÂn, and Chinchorro Bank. For the north-eastern area, GonzaÂlez-Cano et al. (in press) conducted a cohort analysis based on length-frequencies for the fishing seasons 1982/83 to 1994/95. They found that in 1988/89 and further on, the number of new recruits to the fishery (MLS for that period was 145 mm AL) had declined to about 20% of the numbers before that season, thus explaining the low catches after 1988. To overcome this decline, these authors urged a reduction in nominal effort to 75% its value in 1986/87. GonzaÂlezCano et al. (in press) also attempted a global analysis for the whole P. argus fishery in Quintana Roo, despite the above-mentioned difficulties in standardizing effort. They concluded that, currently, the nominal fishing effort is about 330% above its optimum level, and proposed a progressive reduction in effort, because there are no further areas to expand the P. argus fishery in Quintana Roo. Lozano-AÂlvarez (1992) used CPUE and capture±recapture data to estimate lobster biomass in BahõÂ a de la AscensioÂn in two fishing seasons, one (Y1) when the catch from this bay was average (47 578 kg of lobster tails) and another one (Y2) when the

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catch was above average (67 071 kg of lobster tails). The total estimated biomass was 83 235 kg of lobster tails in Y1, and 130 515 in Y2, i.e. catch throughout the 8 months (June±February) of a fishing season amounted to about half of the total lobster biomass in this bay. Lozano-AÂlvarez (1992) also found a high turnover rate of lobsters in the bay, and concluded that the biomass of lobsters in a given fishing season might be related to the magnitude of post-larval recruitment into the bay 2 years before. This hypothesis is currently being explored. Sosa-Cordero et al. (1996) estimated some population parameters of P. argus from Chinchorro Bank based on length-frequency analysis. These authors concluded that the average exploitation rates in Chinchorro (0.71±0.83) are within the ranges that maximize the relative yield per recruit according to the model by Beverton and Holt, and warned against any increase in nominal effort (number of boats and fishermen) to avoid reductions in yield.

9.6

Discussion and perspectives

After the Federal Law for Fisheries was changed in 1992, the spiny lobster fisheries in Mexico have undergone many changes. Although concessions have so far been granted to formerly established co-operatives, not every co-operative has been able to obtain a concession. Before 1992, the government provided financial aid to cooperatives, but currently the private industry has, in many cases, replaced the government in this function (Salas & Torres, 1997). In certains areas of coastal Mexico, the strong development of tourism as a major industry during the 1980s and 1990s has had a number of effects on different fisheries. For example, in Sinaloa, Jalisco, MichoacaÂn, Guerrero and Oaxaca (Fig. 9.1a), the lobster catch increased from the late 1970s through to the early 1990s as a result of the development of large touristic resorts which increased the local demand for lobsters. However, in Quintana Roo, following the decline in catches after 1989, many former lobster fishers have turned to other, more profitable activities, such as taking tourists to sport fishing, diving or snorkelling. Management of the spiny lobster fisheries in Mexico has historically been complicated, partly because the goals of the managers have tended to favour shorttime yield and revenues instead of long-term benefits (Salas & Torres, 1997), and partly owing to the scarcity of biological studies on the lobster resources and longterm assessment of the fisheries. However, some progress has been achieved in the last few years. Information on the biology and ecology of lobster species has increased, and some studies, particularly on P. interruptus and P. argus, but also on the rest of the species, have been important to prompt changes in certain regulations. For example, the stepped closures for P. interruptus in Baja California were first introduced in 1995, based on the latitudinal progression in reproduction and size distribution of the lobster population along the peninsula (Vega et al., 1996). Since then, the catch has been recovering to its prior levels (Fig. 9.2), but it is still too soon

182 Spiny Lobsters: Fisheries and Culture to determine whether this is mainly due to the change in regulations. Vega et al. (1997) concluded that a sustainable fishery has apparently been achieved for P. interruptus and that there are no possibilities for its further expansion. However, fishing effort is highly concentrated in the central region of Baja California, and the fishing regime does not explain the changes in lobster abundance. New studies which take into consideration the effect of variability in oceanographic factors (such as those produced in ENSO years; Vega & Lluch-Cota, 1992; Vega et al., in press) on the availability of the resource are promising better tools for managing this fishery in the near future. The reduction in 1993 of the MLS of P. inflatus and P. gracilis from MichoacaÂn to Chiapas was based on a number of studies conducted mainly in Guerrero and Sinaloa, but it took the fishing authorities over 10 years to introduce this change after scientists first suggested it (Briones-FourzaÂn et al., 1981). So far, this change in MLS has not had any effect on the catches of these two species. Nevertheless, the fisheries for these two species are the least developed in Mexico, and some researchers believe that there are still unexploited fishing grounds throughout the Pacific coast, which should be explored to assess their potential. In the case of P. argus, the catch has remained erratic since 1989. In particular, Quintana Roo has suffered a significant decrease in the catch in 1989±1997, to around half the level in 1988. Fishing effort is also highly concentrated in northeastern Quintana Roo (GonzaÂlez-Cano, 1991), but the major problem to assess this fishery, and the YucataÂn fishery as well, is the use of such a variety of fishing methods, which has impeded the reliable estimation of fishing effort and hence its efficient control. As a consequence, only a few portions of the fishery have been assessed. These assessments, however, are of a limited extent because of the complex life cycle of P. argus, the highly migratory nature of its benthic populations, and the high variability in ecological and environmental factors surrounding the lobster populations, for which little information exists. Moreover, the fishery for P. argus in the state of YucataÂn is only one component of a multispecies fishery, further complicating the assessment and management of this particular fishery. However, despite the difficulties originated by the uncertainties in fishing effort, most scientists involved in this fishery agree that effort should not be allowed to increase. An additional problem in managing the Mexican spiny lobster fisheries is the chronic failure to enforce regulations efficiently. Penalties for infringing the regulations are severe, and some co-operatives also have their own enforcement agreements, but surveillance is not always strict. Therefore, the observance of regulations varies widly among areas and fisheries. This also affects the reliability of databases on catch and effort. As a consequence, data obtained from different sources seldom coincide, and scientists have a hard time in trying to decide which ones to use in their assessments. Some even design specific logbooks to obtain the best possible data directly from the fishers.However, the results of long-term research and monitoring, designed to understand the dynamics of the stocks, are

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seldom published in scientific or technical papers, and hence are of limited distribution. Co-operation between fishermen, researchers and managers, which is of major importance to reconcile the disparate interests of the different sectors involved in the lobster fisheries, as well as to evaluate the success of management programmes, has historically depended on political decisions, and does not exist for prolonged periods. Perhaps an exception to this situation is the fishery for P. interruptus, where fishers, scientists and industrials, have managed to keep their communication channels open. In other fisheries, the situation is different. For example, in 1993, the government issued a ban on the use of the gaff in the P. argus fishery to reduce mortality of undersize lobsters. This measure was opposed by most fishers, who refused to observe it, because a large percentage of fishers in YucataÂn and Quintana Roo were divers, and they used the gaff to extract the lobsters from their dens. To observe this measure fishers would require to change their fishing methods (to traps or casitas), for which they would need more credits to invest in gear and equipment, at a time when catches were poor and debts were already high. Finally, in 1998 this ban was derogued. Ironically, the development of the new live lobster industry since 1996, which is clearly more profitable to fishers because of the better unit value of live lobsters, has had the indirect consequence of a gradual abandonment of the use of gaffs, and the extended use of casitas or traps, at least in certain areas. To catch the lobsters in the best possible conditions for this industry, fishermen now extract lobsters from casitas with hoop nets or seine nets. Economic incentives worked better than biological concerns about the resource. Many authors (e.g. Sharp, 1997) have invoked the need for an ecosystem management of fisheries that should pay greater attention to the ecosystem where the species live, as well as to the environmentally driven variations of fisheries. Most of the spiny lobster species in Mexico inhabit tropical, complex benthic communities, but studies on these communities, and on their responses to climatic and oceanographic processes, are extremely scarce. For example, the low numbers of new recruits to the fishery of P. argus since 1989 estimated by GonzaÂlez-Cano et al. (in press) indicate a recruitment failure the causes of which are unknown, although these authors believe that it was an indirect cause of Hurricane Gilbert. Augmenting the knowledge on these issues will, in the long term, increase the possibilities for better management strategies. However, the tremendous amount of information needed to achieve the ecosystem management (Larkin, 1997), especially in tropical ecosystems, and its associated costs, make this approach currently unrealistic for the Mexican fisheries. Some more pragmatic approaches, such as truly limiting the access to the fisheries and effectively controlling fishing effort (the `precautionary principle'), would perhaps work better for managing the Mexican lobster fisheries at this stage. Even this approach, however, relies on a better co-operation among government, scientists, fishermen and industry, to obtain the critical data needed to develop sound management strategies on a long-term basis.

184 Spiny Lobsters: Fisheries and Culture

References Anon. (1998) Anuario EstadõÂstico de Pesca 1997. SrõÂ a. Medio Ambiente, Rec. Nat. y Pesca, MeÂxico, 241 pp. Arceo, P. (1991) AnaÂlisis bioeconoÂmico de funciones captura-esfuerzo de la pesquerõÂ a artesanal de langosta Panulirus argus (Latreille, 1804). Tesis de MaestrõÂ a, CINVESTAV-Unidad MeÂrida, Inst. PoliteÂcn. Nacional, MeÂxico, 84 pp. Arceo, P. & Seijo, J.C. (1991) Fishing effort analysis of the small-scale spiny lobster (Panulirus argus) fleet of the YucataÂn shelf. FAO Fish. Rep., 431 (Suppl.), 59±74. Ayala, Y. (1976) Aspectos bioloÂgicos de la langosta roja Panulirus interruptus (Randall 1846) del aÂrea comprendida entre Punta Malarrimo y La Lobera (5 km al sur de Punta Eugenia, B.C.S.). In Memorias del Simposio sobre Recursos Pesqueros Masivos de MeÂxico, Vol. Especial sobre AbuloÂn/Langosta, 28±30 Sept. 1976, Ensenada, MeÂxico (Ed. by A. Villamar), pp. 37±72. Inst. Nal. Pesca, MeÂxico. Ayala, Y. (1983) Madurez sexual y aspectos reproductivos de la langosta roja, Panulirus interruptus (Randall) en la costa oeste central de Baja California, MeÂxico. Ciencia Pesquera, Inst. Nal. Pesca SrõÂa. Pesca (Mexico), 4, 33±48. Ayala, Y. & ChaÂvez, H. (1985) Nota sobre la colecta de larvas y juveniles de langosta roja, Panulirus interruptus (Randall), en la costa occidental de Baja California, MeÂxico. Ciencias Marinas, 11(2), 93±100. Ayala, Y., GonzaÂlez-AvileÂs, J.G. & Espinoza-Castro, G. (1988) BiologõÂ a y pesca de langosta en el PacõÂ fico Mexicano. In Los Recursos Pesqueros del PaõÂs, pp. 251±86. SecretarõÂ a de Pesca, MeÂxico, D.F. Briones-FourzaÂn, P. (1993) Reclutamiento de postlarvas de la langosta Panulirus argus (Latreille, 1804) en el Caribe mexicano: patrones, posibles mecanismos e implicaciones pesqueras. Tesis Doctoral, Fac. Ciencias, Univ. Nal. AutoÂn. MeÂxico, 140 pp. Briones-FourzaÂn, P. (1994) Variability in postlarval recruitment of the spiny lobster Panulirus argus to the Mexican Caribbean coast. Crustaceana, 66, 326±40. Briones-FourzaÂn, P. (1995a) BiologõÂ a y pesca de las langostas en MeÂxico. In Temas Selectos de OceanografõÂa BioloÂgica en MeÂxico (Ed. by F. GonzaÂlez & J. De la Rosa), pp. 207±36. Univ. AutoÂn. de Baja California, Ensenada. Briones-FourzaÂn, P. (1995b) Diferencias y similitudes entre Panulirus argus y P. guttatus, dos especies de langosta comunes en el Caribe mexicano. Rev. Cubana Inv. Pesq., 19(2), 14±20. Briones-FourzaÂn, P. & Lozano-AÂlvarez, E. (1982) Nuevas localidades en la distribucioÂn de Panulirus penicillatus (Olivier) y P. inflatus (Bouvier) en MeÂxico (Crustacea: Decapoda: Palinuridae). An. Inst. Cienc. del Mar y Limnol. Univ. Nal. AutoÂn. MeÂxico, 9, 389±94. Briones-FourzaÂn, P. & Lozano-AÂlvarez, E. (1992) Aspects of the reproduction of Panulirus inflatus (Bouvier) and P. gracilis Streets (Decapoda: Palinuridae) from the Pacific coast of Mexico. J. Crustacean Biol., 12, 41±50. Briones-FourzaÂn, P., Lozano-AÂlvarez, E., MartõÂ nez, A. & CorteÂs, S. (1981) Aspectos generales de la biologõÂ a y pesca de las langostas en Zihuatanejo, Gro., MeÂxico (Crustacea: Palinuridae). An. Inst. Cienc. del Mar y Limnol. Univ. Nal. AutoÂn. MeÂxico, 8, 79±102. Chapa, H. (1964) ContribucioÂn al conocimiento de las langostas del PacõÂ fico mexicano y su pesquerõÂ a. Inst. Nal. Invest. Biol. Pesq. SrõÂa. Ind. Comercio, Publ. 6, 68 pp. Engle, J. (1979) Ecology and growth of juvenile California spiny lobsters (Panulirus interruptus Randall). Ph.D. diss., University of Southern California, Los Angeles, USA, 298 pp. FernaÂndez-LomelõÂ n, M. P. (1992) Potencial reproductivo de las langostas Panulirus gracilis Streets, 1871, y Panulirus inflatus (Bouvier, 1895). Tesis Prof., Fac. Ciencias, Univ. Nal. AutoÂn. MeÂxico, 52 pp.

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Flores-CampanÄa L.M. & PeÂrez-GonzaÂlez, R. (1991) New record of Panulirus penicillatus (Olivier 1791) in the southeastern Gulf of California, Mexico (Crustacea: Decapoda: Palinuridae). Rev. Biol. Trop., 39, 183±4. Flores-CampanÄa, L.M., PeÂrez-GonzaÂlez, R. & NuÂnÄez-PasteÂn, A. (1993) La pesquerõÂ a de las langostas Panulirus inflatus (Bouvier) y P. gracilis (Streets) en la costa sureste del Golfo de California. In Memorias del Taller la UtilizacioÂn de Refugios Artificiales en las PesquerõÂas de Langosta, Isla Mujeres, MeÂxico, 17±21 May 1993 (Ed. by J.M. GonzaÂlez-Cano & R. Cruz), pp. 113±21. SEPESCA, MeÂxico. Fonseca-Larios, M. & Briones-FourzaÂn, P. (1998) Fecundity of the spiny lobster Panulirus argus (Latreille, 1804) in the Caribbean coast of Mexico. Bull. Mar. Sci., 63, 21±32. Fuentes, D. (1988) Investigaciones pesqueras de la langosta en el Caribe mexicano. In Los Recursos Pesqueros del PaõÂs, pp. 441±62. SecretarõÂ a de Pesca, MeÂxico, D.F. Fuentes, D., Arceo, P. & Salas, S. (1991) Consideraciones preliminares para el manejo de la pesquerõÂ a de langosta en YucataÂn. In Taller Regional sobre Manejo de la PesquerõÂa de la Langosta (Ed. by P. Briones-FourzaÂn). Inst. Cienc. del Mar y Limnol. Univ. Nal. AutoÂn. MeÂxico Publ. TeÂcn., 1, 66±74. GonzaÂlez-Cano, J. (1991) Migration and refuge in the assessment and management of the spiny lobster Panulirus argus in the Mexican Caribbean. Ph.D. thesis, Imperial College, University of London, UK, 448 pp. GonzaÂlez-Cano, J., RõÂ os-Lara, V., RamõÂ rez-EsteÂvez, A., Zetina-Moguel, C., Aguilar-Cardozo, C., Cervera-Cervera, K., MartineÂz, J.D., Mena-Aguirar, R. & CobaÂ-Rios, M.T. Langosta del Caribe, Panulirus argus. In Sustentabilidad y Pesca Responsable en MeÂxico. EvaluacioÂn y Manejo 1997±98 (Ed. by P. Arenas & A. DõÂ az de LeoÂn). SEMARNAP/CONABIO, MeÂxico (in press). Gracia, A. (1985) VariacioÂn estacional en la fecundidad de la langosta Panulirus inflatus (Bouvier, 1895) (Crustacea: Decapoda: Palinuridae). Ciencias Marinas, 11, 7±27. Gracia, A. & Kensler, C.B. (1980) Las langostas de MeÂxico: su biologõÂ a y pesquerõÂ a. An. Inst. Cienc. del Mar y Limnol. Univ. Nal. AutoÂn. MeÂxico, 7, 111±28. Gracia, A. & Lozano-AÂlvarez, E. (1980) AlimentacioÂn del bagre marino, Netuma platypogon, y su importancia como indicador de reclutamiento de postlarvas de langosta (Decapoda: Palinuridae) en Guerrero, MeÂxico. An. Inst. Cienc. del Mar y Limnol. Univ. Nal. AutoÂn. MeÂxico, 7, 199±206. GutieÂrrez, D., SimonõÂ n, J. & Briones-FourzaÂn, P. (1992) A simple collector for postlarvae of the spiny lobster Panulirus argus. Proc. Gulf Caribb. Fish. Inst., 41, 516±27. GuzmaÂn del Proo, S. A. & Pineda, J. (1992) AnaÂlisis poblacional de la pesquerõÂ a de langosta roja (Panulirus interruptus) de 1971±1975 en la Bocana-Abreojos, B.C.S., MeÂxico. In Memorias del Taller MeÂxico-Australia sobre Reclutamiento de Recursos BentoÂnicos de Baja California, La Paz, B.C.S., MeÂxico, 25±29 November 1991 (Ed. by S. GuzmaÂn del Proo), pp. 167±77. SEPESCAIPN. GuzmaÂn del Proo, S.A., Carrillo-Laguna, J., Belmar-PeÂrez, J., Campa, S. de la & Villa, A. (1996) The puerulus settlement of red spiny lobster (Panulirus interruptus) in BahõÂ a Tortugas, Baja California, MeÂxico. Crustaceana, 69, 949±57. Holthuis, L. & Villalobos, A. (1961) Panulirus gracilis Streets y Panulirus inflatus (Bouvier), dos especies de langosta (Crustacea, Decapoda) de la costa del PacõÂ fico de AmeÂrica. An. Inst. Biol. Univ. Nal. AutoÂn. MeÂxico, 32, 251±76. Johnson, M.W. (1956) The larval development of the California spiny lobster, Panulirus interruptus (Randall), with notes on P. gracilis Streets. Proc. Calif. Acad. Sci., 22(1), 1±19. Johnson, M.W. & Knight, M. (1966) The phyllosoma larvae of the spiny lobster Panulirus inflatus (Bouvier). Crustaceana, 10, 31±47. Larkin, P.A. (1997) The costs of fisheries management information and fisheries research. In Developing and Sustaining World Fisheries Resources (Ed. by D.A. Hancock, D.C. Smith, A. Grant & J.P. Beumer), pp. 713±18. CSIRO Publishing, Australia.

186 Spiny Lobsters: Fisheries and Culture Lewis, J.B. (1951). The phyllosoma larvae of the spiny lobster, Panulirus argus. Bull. Mar. Sci. Gulf Carribb., 1, 89±103. Lindberg, R.G. (1955) Growth, population dynamics and field behavior in the spiny lobster, Panulirus interruptus (Randall). Univ. Calif. Publ. Zool., 59, 157±248. Lozano-AÂlvarez, E. (1992) PesquerõÂ a, dinaÂmica poblacional y manejo de la langosta Panulirus argus (Latreille, 1804) en la BahõÂ a de la AscensioÂn, Quintana Roo, MeÂxico. Tesis Doctoral, Fac. Ciencias, Univ. Nal. AutoÂn., MeÂxico, 142 pp. Lozano-AÂlvarez, E. (1994) AnaÂlisis del estado de la pesquerõÂ a de la langosta Panulirus argus en el Caribe mexicano. In Recursos faunõÂsticos del Litoral de la PenõÂnsula de YucataÂn (Ed. by A. YaÂnÄez), pp. 43±55. Univ. AutoÂn. Campeche-EPOMEX, Serie CientõÂ fica, Vol. 2. Lozano-AÂlvarez, E. & Aramoni-Serrano, G. (1996) AlimentacioÂn y estado nutricional de las langostas Panulirus inflatus y Panulirus gracilis (Decapoda: Palinuridae) en Guerrero, MeÂxico. Rev. Biol. Trop., 44, 453±61. Lozano-AÂlvarez, E., Briones-FourzaÂn, P. & GonzaÂlez-Cano, J. (1991a) Pesca exploratoria de langostas con nasas en la plataforma continental del aÂrea de Puerto Morelos, Q.R., MeÂxico. An. Inst. Cienc. del Mar y Limnol. Univ. Nal. AutoÂn. MeÂxico, 18(1), 49±58. Lozano-AÂlvarez, E., Briones-FourzaÂn, P. & Negrete, F. (1993) Occurrence and seasonal variations of spiny lobsters, Panulirus argus (Latreille), on the shelf outside BahõÂ a de la AscensioÂn. Fish. Bull. U.S., 91, 808±15. Lozano-AÂlvarez, E., Briones-FourzaÂn, P. & Phillips, B.F. (1991b) Fishery characteristics, growth, and movements of the spiny lobster Panulirus argus in BahõÂ a de la AscensioÂn, MeÂxico. Fish. Bull. U.S., 89, 79±89. Lozano-AÂlvarez, E., Briones-FourzaÂn, P., Santarelli, L. & Gracia, A. (1982) Densidad poblacional de Panulirus gracilis Streets y Panulirus inflatus (Bouvier) (Crustacea: Palinuridae) en dos aÂreas cercanas a Zihuatanejo, Gro., MeÂxico. Ciencia Pesquera, Inst. Nal. Pesca, SrõÂa. Pesca, 3, 61±73. Lyons, W.F. (1980) The postlarval stages of scyllaridean lobsters. Fisheries, 5(4), 47±9. Marx, J.M. & Herrnkind, W.F. (1985) Macroalgae (Rhodophyta: Laurencia spp.) as habitat for young juvenile spiny lobsters, Panulirus argus. Bull. Mar. Sci., 36, 423±31. Medina, H. (1982) MeÂxico en la Pesca. Editorial HMN, MeÂxico, 381 pp. Miller, D.L. (1982) Mexico's Caribbean fishery: recent change and current issues. Ph.D. thesis, University of Wisconsin-Milwaukee, USA, 250 pp. Mitchell, C.T., Turner, H. & Strachan, A.R. (1969) Observations on the biology and behavior of the California spiny lobster, Panulirus interruptus (Randall). Calif. Fish Game, 55(2), 121±31. Padilla-Ramos, S. & Briones-FourzaÂn, P. (1997) Biological characteristics of the spiny lobsters (Panulirus spp.) from the commercial catch in Puerto Morelos, Quintana Roo, Mexico. Ciencias Marinas, 23(2), 175±93. Parker, K.P. (1972) Recruitment and behavior of puerulus larvae and juveniles of the California spiny lobster, Panulirus interruptus. Master's thesis, San Diego State University, USA, 91 pp. PeÂrez-GonzaÂlez, R., Flores-CampanÄa, L.M. & NuÂnÄez-PasteÂn, A. (1992a) AnaÂlisis de la distribucioÂn de tallas, captura y esfuerzo en la pesquerõÂ a de langostas Panulirus inflatus (Bouvier, 1895) y P. gracilis Streets, 1871 (Decapoda: Palinuridae) en las costas de Sinaloa, MeÂxico. Proc. San Diego Soc. Nat. Hist., 15, 1±5. PeÂrez-GonzaÂlez, R., Flores-CampanÄa, L.M., NuÂnÄez-PasteÂn, A. & Ortega-Salas, A. (1992b) Algunos aspectos de la reproduccioÂn en Panulirus inflatus (Bouvier) y P. gracilis Streets (Decapoda: Palinuridae) en el sureste del Golfo de California, MeÂxico. Inv. Mar. CICIMAR, 7, 1±9. Phillips, B.F., Pearce, A.F., Litchfield, R. & GuzmaÂn del Proo, S.A. (1994) Spiny lobster catches and the ocean environment. In Spiny Lobster Management (Ed. by B.F. Phillips, J.S. Cobb & J. Kittaka), pp. 250±61. Fishing News Books, Blackwell Scientific Publications, Oxford, UK. Pineda, J. & DõÂ az de LeoÂn, A.J. (1976) Informe de la temporada de pesca 1973±74 de langosta roja (Panulirus interruptus). ComposicioÂn de la captura y esfuerzo de pesca en el noroeste de Baja California. In Memorias del Simposio sobre Recursos Pesqueros Masivos de MeÂxico, Vol.

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Especial sobre AbuloÂn / Langosta. 28±30 Sept. 1976, Ensenada, MeÂxico (Ed. by A. Villamar), pp. 103±44. Inst. Nal. Pesca, MeÂxico. Pineda, J., DõÂ az de LeoÂn A.J. & Uribe, F. (1981) Fecundidad de langosta roja Panulirus interruptus (Randall 1842) en Baja California. Ciencia Pesquera, Inst. Nal. Pesca SrõÂa. Pesca, MeÂxico, 1, 99±118. RamõÂ rez, A.E. (1997). ReproduccõÂ on de la langosta espinosa Panulirus argus (Latreille, 1804) en la costa noreste de Quintanca Roo. Tesis de MaestrõÂ a Fac. Ciencias, Univ. Nal. AutoÂn. MeÂxico, 85 pp. Ramos, R. (1974) El recaloÂn de Contoy. Est. Biol. Pesq. Isla Mujeres, Inst. Nal. Pesca, MeÂxico, Bol. No. 1, 1±7. RõÂ os, G V. & Zetina, C.E. (1997) EstimacioÂn de la poblacioÂn de langosta utilizando el meÂtodo de anaÂlisis de cohortes por longitudes. Informe ineÂdito, CRIP-YucalpeteÂn, Inst. Nal. Pesca, MeÂxico. RõÂ os, G.V., Zetina, C.E. & Cervera, K. (1995) EvaluacioÂn de `casitas' o refugios artificiales introducidos en la costa oriente del estado de YucataÂn para la captura de langostas. Rev. Cubana Inv. Pesq., 19(2), 50±6. Salas, S. & Torres, R. (1997) Factors affecting management in a Mexican fishery. In Developing and Sustaining World Fisheries Resources (Ed. by D.A. Hancock, D.C. Smith, A. Grant & J.P. Beumer), pp. 767±71. CSIRO Publishing, Australia. Salas, S., Seijo, J.C., Arceo, P. & Arce, M. (1991) DistribucioÂn espacio-temporal del esfuerzo pesquero de la flota artesanal de la langosta Panulirus argus en la plataforma yucateca. Rev. Inv. Mar. (Cuba), 12(1±3), 293±9. SecretarõÂ a de Pesca (1987) PesquerõÂas Mexicanas: Estrategias para su AdministracioÂn. Dir. Gral. InformaÂt., EstadõÂ st. y Document., SrõÂ a. Pesca, MeÂxico, 1061 pp. Seijo, J.C., Arceo, P., Salas, S. & Arce, M. (1994) La pesquerõÂ a de la langosta (Panulirus argus) de las costas de YucataÂn: Recurso, usuarios y estrategias de manejo. In Recursos faunõÂsticos del litoral de la PenõÂnsula de YucataÂn (Ed. by A. YaÂnÄez), pp. 33±41. Univ. AutoÂn. CampecheEPOMEX, Serie CientõÂ fica, Vol. 2. Seijo, J.C., Salas, S., Arceo, P. & Fuentes, D. (1991) AnaÂlisis bioeconoÂmico comparativo de la pesquerõÂ a de langosta Panulirus argus de la plataforma continental de YucataÂn. F.A.O. Fish. Rep., 431 (Suppl.), 39±58. Sharp, G.D. (1997) It's about time: rethinking fisheries management. In Developing and Sustaining World Fisheries Resources (Ed. by D.A. Hancock, D.C. Smith, A. Grant & J.P. Beumer), pp. 731±6. CSIRO Publishing, Australia. Sims, H.W. & Ingle, R.M. (1966) Caribbean recruitment of Florida's spiny lobster populations. Q. J. Fla. Acad. Sci., 29, 207±42. Sosa-Cordero, E., RamõÂ rez-GonzaÂlez, A. & DomõÂ nguez-Viveros, M. (1996) EvaluacioÂn de la pesquerõÂ a de langosta (Panulirus argus) de Banco Chinchorro, Quintana Roo, MeÂxico, con base en el anaÂlisis de frecuencia de tallas. Proc. Gulf Caribb. Fish. Inst., 44, 103±20. Vega, A., & Lluch-Cota, D. (1992) AnaÂlisis de las fluctuaciones en los voluÂmenes de captura de langosta en las principales aÂreas de pesca de Baja California Sur y su relacioÂn con factores ambientales durante el perõÂ odo 1970±1991. In Memorias del Taller MeÂxico-Australia sobre Reclutamiento de Recursos BentoÂnicos de Baja California, La Paz, B.C.S., MeÂxico, 25±29 November 1991 (Ed. by S. GuzmaÂn del Proo), pp. 191±212. SEPESCA-IPN. Vega, A., Espinoza, G. & GoÂmez, C. (1996) PesquerõÂ a de langosta Panulirus spp. In Estudio del Potencial Pesquero y AcuõÂcola de Baja California Sur, Vol. 1 (Ed. by M. Casas-ValdeÂz & G. Ponce-DõÂ az), pp. 227±61. CIBNOR, La Paz. Vega, A., Espinoza, G., GoÂmez, C. & Sierra, P. Langosta espinosa de la PenõÂ nsula de Baja California, Panulirus spp. In Sustentabilidad y Pesca Responsable en MeÂxico. EvaluacioÂn y Manejo 1997±98 (Ed. by Instituto Nacional de la Pesca). SEMARNAP/CONABIO, MeÂxico (in press).

188 Spiny Lobsters: Fisheries and Culture Vega, A., Lluch-Belda, D., MucinÄo, M., LeoÂn, G., HernaÂndez, S., Lluch-Cota, D., Ramade, M. & Espinoza, G. (1997) Development, perspectives and management of lobster and abalone fisheries off Northwest Mexico, under a limited access system. In Developing and Sustaining World Fisheries Resources (Ed. by D. A. Hancock, D.C. Smith, A. Grant & J.P. Beumer), pp. 136±42. CSIRO Publishing, Australia. Weinborn, J.A. (1977) Estudio preliminar de la biologõÂ a, ecologõÂ a y semicultivo de los PalinuÂridos de Zihuatanejo, Gro., MeÂxico, Panulirus gracilis Streets y Panulirus inflatus (Bouvier). An. Inst. Cienc. del Mar y Limnol. Univ. Nal. AutoÂn. MeÂxico, 4, 27±78. Zetina, M.C. & RõÂ os, G.V. (1997) EstimacioÂn de la biomasa y la mortalidad por pesca de la langosta espinosa en las costas de YucataÂn, utilizando un modelo de diferencia con retraso. Informe ineÂdito, CRIP-YucalpeteÂn, Inst. Nal. Pesca, MeÂxico. Zimmer-Faust, R.K. & Spanier, E. (1987) Gregariousness and sociality in spiny lobsters: implications for den habitation. J. Exp. Mar. Biol. Ecol., 105, 57±71.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 10

Status of the Fishery for Panulirus argus in Florida J. H. HUNT Florida Department of Environmental Protection, Marine Research Institute, South Florida Research Laboratory, 2796 Overseas Highway, Suite 119, Marathon, FL 330502227, USA

10.1

Introduction

The fishery for Panulirus argus has evolved from a small undercapitalized fishery to a large, economically important, heavily capitalized fishery during the course of the twentieth century. This growth has evoked considerable management concern and controversy, especially during the 1980s and 1990s. This chapter reviews two pivotal events in the development of the fishery, pertinent research that has led to the newly instituted management plan, the Lobster Trap Certificate Program (Florida Statutes, 1992), and then describes this plan, which will shape the course of spiny lobster management over the next decade.

10.2

Development of the fishery

The spiny lobster fishery in Florida has evolved from a fishery dominated by the use of bully nets (Crawford & De Smidt, 1922) in the early 1900s to a fishery that, by the 1950s, primarily used wooden slat-traps similar to those in use today (Labisky et al., 1980). Complete descriptions of the early fishery, landings and effort are provided by Labisky et al. (1980) and Simmons (1980). By the early 1960s, landings had reached 4±6 million kg annually (Fig. 10.1), harvested from 75 000 to 100 000 traps (Simmons, 1980). In addition to technological advances of vessels and in fishing capability, two pivotal events occurred that influenced the rapid increase of traps during the 1960s and 1970s. First, minimum size was reduced from a 2.2 kg lobster [about 79 mm carapace length (CL)] to a 76.2 mm CL lobster in 1965. Secondly, the Bahamian government no longer permitted American fishermen to fish for lobsters in Bahamian waters after 1975. Robinson & Dimitriou (1963), in their status report of the fishery, observed that lobster abundance and size structure were similar in 1945±1949 and in 1962±1963, but noted that the increasing effort occurring in the fishery at that time was not resulting in an equivalent increase in catch. They concluded that existing size regulations were appropriate, but recommended that the legal definition be changed from a 2.2 kg lobster to its CL equivalent,79 mm. Simultaneously, fishermen desired 189

190 Spiny Lobsters: Fisheries and Culture

Fig. 10.1 Spiny lobster landings from the commercial lobster fishery for Panulirus argus for the calendar years 1961±1991. West coast = Monroe County (Florida Keys) and northward along the west coast (Gulf of Mexico) of Florida. East coast = Dade County (Miami) and northward along the east coast of Florida. Most lobsters are landed in Monroe County. Data taken from Powers & Sutherland (1989) and the Florida Department of Natural Resources Marine Fisheries Information System (R. Muller, pers. comm.).

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191

a reduction in size to 70 mm. Robinson & Dimitriou argued that if the minimum size were reduced, any gains in harvest would be likely be to temporary. The Florida legislature selected a minimum legal size of 76 mm CL, a reduction of about 3 mm. This reduction, along with increased use of cowhide (Labisky et al., 1980), opened Florida Bay to fishing. The fishery thus entered those areas where sublegal-sized lobster comprise more than 80% of the population for most of the year (Lyons et al., 1981). The expansion of effort to Florida Bay probably began the development in the use of sublegal lobster as live attractants in traps. Landings in Florida increased throughout the 1960s and early 1970s (Fig. 10.1) as effort increased (Fig. 10.2; also Simmons, 1980). However, much of those landings were lobsters harvested from Bahamian waters, and listed under Florida east coast landings (Fig. 10.1) (Labisky et al., 1980; Powers & Sutherland, 1989). Florida east coast landings after 1975, the final year of fishing Bahamian waters, have fluctuated below 2.2 million kg, with the exception of 1977 (Fig. 10.1). Florida east coast landings in excess of 2.2 million kg were probably harvested from Bahamian waters. Consequently, Florida west coast (mostly Florida Keys) landings are considered the best barometer of actual harvest for those years (Powers & Sutherland, 1989). By the early 1970s, total traps had reached about 250 000 and total harvest (west coast) was averaging in excess of 11 million kg (Labisky et al., 1980).

Fig. 10.2 Spiny lobster landings from the commercial lobster fishery for Panulirus argus expressed as a function of the estimated number of traps fished. The line was drawn by eye through the approximate midpoint of the data and is used for illustrative purposes only. Data for 1961±1991 taken from same sources as in Fig. 10.1 (west coast landings only). Data prior to 1961 taken from Labisky et al. (1980).

192 Spiny Lobsters: Fisheries and Culture In 1975, the loss of Bahamian waters to fishing caused an explosion of effort in the Florida fishery. Trap numbers increased to over 500 000 (Labisky et al., 1980) but landings did not increase. Further increases in effort have resulted in no further increase in landings (Fig. 10.2). Post-1975 statewide harvest has fluctuated without trend around a mean of about 13 million kg; Fig. 10.1). The extremely low harvest during 1983 occurred during an El NinÄo year and appears to have been a Caribbeanwide phenomenon (W.G. Lyons, pers. comm.); the harvest relationship to El NinÄo may be coincidental. El NinÄo is thought primarily to influence recruitment events (Phillips et al., 1991). Other fishery and population measurements are also indicative of an intensive fishery. The fishery has shown an increasing trend towards a shorter effective season as traps numbers increase. The first 3 months of the season produced 55%, 57% and 74% of the total harvest in 1969, 1979 and 1988, respectively (Powers & Sutherland, 1989). In 1988, 93% of the total harvest had been landed by the end of November (the lobster season is August±March). Catch rates of legal and sublegal lobsters in research traps baited with shorts dropped precipitously within 2 weeks after the opening of the 1985 lobster season (Lyons & Hunt, 1992). The size structure of the trappable population has shifted towards an increasing proportion of smaller lobsters (Lyons et al., 1981). Consequently, the commercial fishery relies almost exclusively on new recruitment of legal lobsters in each fishing year (Powers & Sutherland, 1989). Clearly, the spiny lobster fishery in Florida is overcapitalized (Lyons, 1986).

10.3

Present status of the fishery

The commercial fishery of 1992 fishes throughout the Gulf and Atlantic waters of the Florida Keys and along the east coast of Florida northwards to midway up the state (Palm Beach area). During recent years, fishing effort has increased west of the Dry Tortugas (the westernmost islands of the Florida Keys, approx. 126 km west of Key West, FL). That fishing area was probably made continuously accessible upon the increased use of more sophisticated navigation and bottom locating devices. Harvests there often exceeded 6.6 kg per trap pull (approx. 7±10 day soak times) for 2 years, but now have returned to levels similar to the rest of the fishery (R. Beaver, Fisheries Statistics Port Sampler, Marathon, FL., pers. comm.). The mean size of lobsters harvested near the Dry Tortugas was 114.9 mm CL, about 30 mm greater than mean size from the rest of the fishery (Harper, 1991). The state of Florida now requires that all lobster traps display a numbered tag issued by the Florida Department of Natural Resources (FDNR); traps are not limited. The FDNR has issued in excess of 986 000 trap tags to 1870 individuals for the August 1992±March 1993 fishing season (M. Peart, FDNR Saltwater Licenses and Permits Section, Tallahassee, FL, pers. comm.). Individual fisherman fish up to 6000 traps; however, the average number of traps fished is about 520. The low

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average is heavily influenced by the large number of fisherman who supplement their income by fishing a small number of traps. About 800 of the 1870 individuals receiving trap tags are considered to be full-time professional fishermen. These fishermen typically fish in excess of 1000 traps. The larger fishermen begin returning their traps to shore as early as November of each year as they switch to fish other species, notably stone crab (Menippe mercenaria) and Spanish mackerel (Scomberomorus maculatus). An additional 1744 individuals have received spiny lobster endorsements for their saltwater products licence (M. Peart, pers. comm.) entitling them to sell spiny lobster, but they do not fish with traps. These individuals are shrimpers, who sometimes harvest spiny lobsters in their trawls as bycatch, commercial lobster divers, and individuals who do not sell their catch but request the lobster endorsement in order to exceed the recreational bag limit. The total harvest for this last group of fisherman may approach 2.2 million kg annually (R. Palmer, Florida Marine Fisheries Commission, Tallahassee, FL, pers. comm.). During the August 1991±March 1992 season, in excess of 120 000 recreational lobsters licences were purchased (Bertelsen & Hunt, 1991). The recreational licence permits fishermen to capture six lobsters per person during the special sport season and six lobsters per person or 24 per boat, whichever is greater, during the regular season (Florida Administrative Code, 1992). In total, 50 000 recreational licences were purchased during July 1991 prior to the 2-day special sport season and 44 000 recreational licences were purchased during August 1991 (first month of the regular season). Of the estimated 50 000 individuals who fished during the special sport season statewide, 66% or 33 030 fished in the Florida Keys and harvested 950 000 kg of the total 957 000 kg harvest estimated statewide during that season (Bertelsen & Hunt, 1991). During the first month of the regular season the recreational sector landed 41% of the total harvest; they landed 22% of the total harvest for the entire 1991/92 fishing season (Fig. 10.3). Their proportion of the total harvest was considerably greater during 1991 than during 1980, when the recreational sector was estimated to harvest 10% of the commercial harvest (Zuboy, 1980). However, the 1980 estimate was based on a panel of experts participating in a Delphi exercise (Zuboy, 1980), whereas the 1991 estimate was made directly using a mail survey (Bertelsen & Hunt, 1991).

10.4

Research leading to present management plan

During 1979, Florida Department of Natural Resources biologists first suspected that additional problems may exist related, in part, to the expansion of traps in the fishery and opening of Florida Bay when minimum size was reduced (W.G. Lyons, pers. comm.). During the Department's stock assessment study (Lyons et al., 1981), many fisherman that reported capturing tagged sublegal-sized lobsters, locally called shorts, stated that they were using them as `bait' in their traps. Bait lobsters are live

194 Spiny Lobsters: Fisheries and Culture

Fig. 10.3 Comparison of recreational and commercial harvests for Panulirus argus for the first month and entire season of the statewide lobster fishery for the 1991 fishing season.

lobsters placed in traps as attractants. The fisherman were to report again when each lobster was released; most of these fisherman were never heard from again. This experience led to a series of research efforts examining the ramifications of this fishing practice. Researchers mimicking the fishery practice of baiting with shorts found that 28.5% of these live attractants died within 4 weeks (Hunt et al., 1986); as many as 47% of all shorts died during the course of the fishing season either from exposure and handling or from causes related to extended confinement in traps (Kennedy, 1982). Mortality estimates of Hunt et al. (1986) were made directly by placing lobsters in traps and observing mortality on a weekly basis. Exposure-related mortality (that mortality occurring during the first week) was estimated at 18.2%; the remaining mortality was due to confinement. Mortality of confined lobsters increased during their fourth week of confinement at sites where lobster prey species were less abundant. Preliminary mortality studies were sampled longer and mortality was found to increase regardless of trap location beyond 4 weeks (Lyons and Kennedy, 1981). Mortality estimates of Kennedy (1982) were based on the differential return rates of tagged lobsters used as bait compared with lobsters tagged and released into the sea. Daily escape rates of bait lobsters from traps were about 1% (Lyons & Kennedy, 1981). Experiments testing a variety of possible baits, including shorts, found that the use of shorts enhances individual trap catches (Heatwole et al., 1988). Catch in empty (control) traps ranked second; but their catch rates were not significantly greater than those from traps baited with a variety of food-related baits (cowhide, fishheads, etc.). The use of shorts presumably takes advantage of visual, auditory or most likely, chemical (Zimmer-Faust et al., 1985) cues related to the gregarious behaviour of these spiny lobsters. Even though individual trap catch is enhanced, fisheryrelated mortality of bait attractants creates a loss of harvestable lobsters to the fishery (Hunt et al., 1986; Heatwole et al., 1988).

Status of the Fishery for Panulirus argus in Florida

195

Results from these studies led to the development of an escape-gap design appropriate for the Florida fishery. Based on extensive field tests, Lyons & Hunt (1992) concluded that a 52.4 mm escape gap is an appropriate width for fishery implementation. The use of this escape gap reduced the sublegal catch by 90%. Catch rates of legal lobsters in traps baited with cowhide and using this escape gap were 32% less than a standard trap baited with cowhide and 50% less than a standard trap baited with shorts. Lyons & Hunt (1992) concluded that escape gaps provide management's best option to improve spiny lobster harvest, at least within the authority presently provided to the Florida Marine Fisheries Commission. They estimated that 30% of the sublegal lobster population was unaffected (i.e. never trapped) by the fishery, while 70% was affected. If the observed escape rates were afforded to the approximately 8.55 million sublegal lobsters captured by the fishery (the 70% affected component), then the availability of legal-sized lobsters to be caught should increase by 49±62% at present fishery effort levels (Lyons and Hunt, 1992). Powers & Sutherland (1989), using the results from the above reviewed research, concluded in the National Marine Fisheries Service annual stock assessment that alternative fishery practices, notably the implementation of escape gaps, that reduced mortality of sublegal-sized lobsters would measurably increase yield from the commercial fishery. In contrast, Ehrhardt et al. (1991), using a similar yield-perrecruit approach, concluded that at present levels of effort, the use of escape gaps will not enhance yield per recruit. In other words, they conclude that the greater efficiency related to the use of shorts (Heatwole et al., 1988) offsets gains conferred through increasing survivorship through the use of escape gaps (Lyons & Hunt, 1992).

10.5

Present management plan

The 12 years of research and modelling reviewed above, plus a continual public workshop process incorporating fishing industry views and concerns, has led to the present management programme, passage of the spiny lobster trap certificate law and amendments (Florida Statutes, 1992). This law established an individual transferable certificate for the use of a trap, developed a formula to set the initial allocation of certificates, and established the management objective of the trap certificate programme, that being a reduction in the number of traps in the fishery. The law also specifically prohibited the Florida Marine Fisheries Commission from halting the placement of sublegal lobsters into traps or instituting the requirement that escape gaps be added to traps until after 1 April, 1998. Individual fisherman will be issued tags equal to their certificate allocation from the Florida Department of Natural Resources that must be attached to their traps. Traps without tags will be illegal gear. The total initial allocation of certificates is 700 000 and each individual's allocation will be based on their highest reported

196 Spiny Lobsters: Fisheries and Culture landings, subject to a maximum of 66 000 kg, during one of the three benchmark years, fishing seasons 1988/89, 1989/90 or 1990/91. The sum of each individual's highest year landings (using 66 000 kg as a cap) as reported to the Florida Department of Natural Resources was 17 million kg, resulting in a `trap/catch coefficient' of 10.93. Each individual fisherman's initial certificate allocation is calculated by dividing their highest year's harvest by the trap/catch coefficient. Fishermen with a highest year's harvest of 66 000 kg or greater will receive 2743 certificates and tags. The minimum number of certificates allocated to one individual will be 10, regardless of their reported landings. The law provides for individuals to transfer their certificates on a fair market basis. Each transfer must be reported to the Florida Department of Natural Resources and a transfer fee of US $2 per certificate shall be assessed to cover administrative costs and to recover an equitable natural resource rent for the people of the state of Florida. The Department may be asked to re-examine the value of equitable rent in light of the enhanced access that commercial lobster fisherman may receive to this species. To prevent monopolization in this fishery as trap numbers decrease, the law also limits any one entity from controlling, directly or indirectly, more than 1.5% of the total available certificates. The law established a Trap Certificate Technical Advisory and Appeals Board composed of fishermen who have accepted their certificate allocation and agree to serve. The primary purpose of this Board is to consider and advise the Department of Natural Resources on disputes concerning the initial allocation of certificates to fisherman. Disputes may focus on incorrect or lack of reporting of landings by wholesale seafood dealers during the benchmark years, possible hardships that may have limited landings during the benchmark years, and other issues. At the time of writing, the Board had been allotted up to 50 000 certificates to settle these disputes. However, given the number of appeals received up to 1 October 1992 (244) and additional certificates requested (in excess of 165 000), the Board appears likely to request that their allotment of certificates be increased to permit an equitable initial allocation for all legitimate appeals (John Hunt, Board Administrator, pers. obs.). Finally, the law requires that the Florida Marine Fisheries Commission establish a trap reduction programme, not to exceed 10% per year, based on maintaining or maximizing sustained harvest from the fishery. All certificate holders will have their certificates reduced by an equal percentage each year. The Florida Marine Fisheries Commission has set the first year's reduction at 10%. If that rate of reduction is continued, then total traps in the fishery will be reduced to levels that may be optimal in 8±10 years.

10.6

Prognosis for the future

The primary prediction is that lobster landings will remain cyclically stable as traps decrease; the direction of the landings curve will reverse (Fig. 10.2). As the ratio of

Status of the Fishery for Panulirus argus in Florida

197

lobsters to traps shifts towards more lobsters, catch per trap pull should increase while an equivalent total harvest is landed (Heatwole et al., 1988). The effective season (Powers & Sutherland, 1989) may increase; catch rates will remain higher longer. An increase in the effective season may confer the greatest advantage to those fishermen who are primarily spiny lobster fishermen, as opposed to those fishermen who switch to fish other species during the course of the fishing season. Furthermore, the cost of fishing will probably be reduced, thus generally improving the economic picture for the fishery. The number of sublegal lobsters residing in traps is likely to decrease, ameliorating any impacts of fishing practices even in the absence of active measures to reduce sublegal lobster mortality. This greater percentage of sublegal lobsters unaffected by fishery interactions may hasten the predicted shift towards increasing size structure in the lobster population, especially if fisherman shift their fishing activity away from regions where sublegal lobster comprise the bulk of trappable lobsters (e.g. Florida Bay) to other areas. The Florida Department of Natural Resources is developing a shipboard monitoring programme designed to evaluate changes in trappable population structure and changes in the fishery as trap reductions occur and will continue its fishery-dependent monitoring of landings at wholesale lobster dealers. Some concern has been expressed that a lack of understanding of the cyclical nature of lobster harvest may impede progress of the new management plan. Landings appear to fluctuate on a 4- or 5-year pattern (Fig. 10.4). To that end, Muller & Hunt (1992) have developed a preliminary model using Virtual Population Analysis (VPA; Pope, 1972) to track and predict landings in the fishery. This model

Fig. 10.4 Comparison of annual landings for Panulirus argus reported from Monroe County (Florida Keys) to landings predicted from the VPA model of Muller & Hunt (1992).

198 Spiny Lobsters: Fisheries and Culture utilizes catch-at-age tables estimated from length-frequency curves of the harvested catch by year class sequence to calculate the population sizes and fishing mortalities that would be necessary to produce the observed catch-at-age table. The predicted landings reproduced the key features in the observed landings, including the cyclical nature and range of the fluctuations and magnitude of the landings (Fig. 10.4). Although the model does not yet represent the range of dynamics of lobsters and the fishery, it is a positive first step towards understanding the cyclical nature of the fishery in Florida. Future versions will be used to help to evaluate the trap reduction schedule. Commercial fisherman have expressed considerable concern that the recreational fishery may reap most of the benefits of increased lobster availability as trap numbers are reduced. Most certainly, the de facto allocation to the recreational sector has increased during the 1990s (Bertelsen & Hunt, 1991). Mail surveys of the recreational sector will continue on an annual basis. The relative harvests of the commercial and recreational sector should be available should active management of their respective allocations be required. Once traps have been reduced to much lower levels, the efficacy of escape gaps in traps should be re-examined. In a fishing regime where lobsters are more abundant relative to traps in the present conditions in Florida, the likelihood of a lobster entering a trap shortly after deployment should increase (e.g. self-baiting), quickly increasing individual trap efficiency (Heatwole et al., 1988) even in the absence of pre-baiting with a short. In the western Australia rock lobster fishery, there are many fewer traps than in the Florida Keys; escape gaps are an effective management tool there (Brown & Caputi, 1986). Escape gaps may yet prove an effective management tool in the Florida fishery when trap numbers are reduced.

References Bertelsen, R.D. & Hunt, J.H. (1991) Results of the 1991 mail surveys of recreational lobster fishermen (Special Sport Season and Regular Season Surveys). Report to Florida Marine Fisheries Commission, 27 pp. Brown, R.S. & Caputi, N. (1986) Conservation of recruitment of the western rock lobster (Panulirus cygnus) by improving survival and growth of undersize rock lobsters captured and returned by fisherman to the sea. Can. J. Fish. Aquat. Sci., 43, 2236±42. Crawford, D.R. & De Smidt, W.J.J. (1922) The spiny lobster, Panulirus argus, of southern Florida: Its natural history and utilization. Bull. Bur. Fish., 38, 281±310. Ehrhardt, N.M., Legault, C., & Pike, C.S. III (1991) Evaluation of the use of sub-legal lobsters (shorts) as attractants (bait) in the Florida spiny lobster fishery. Report to the Lobster Trust Fund. University of Miami, Miami, FL, USA, 109 pp. Florida Administrative Code (1992) Florida Marine Fisheries Commission, Spiny Lobster Rules, Chapter 46, No. 24. Florida Statutes (1992) Spiny Lobster Trap Certificate Program, Chapter 370, No. 142. Harper, D.E. (1991) Trends in the Spiny Lobster Commercial Fishery of Florida, 1960±1990. National Marine Fisheries Service, Southeast Fisheries Center, Miami, FL, MIA-91/92±01, 29 pp.

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Heatwole, D.W., Hunt, J.H. & Kennedy, F.S., Jr (1988) Catch efficiencies of live lobster decoys and other attractants in the Florida spiny lobster fishery. Fla. Mar. Res. Publ., No. 44, 16 pp. Hunt, J.H., Lyons, W.G. & Kennedy, F.S., Jr (1986) Effects of exposure and confinement on spiny lobsters, Panulirus argus, used as attractants in the Florida trap fishery. Fish. Bull., 84, 69±76. Kennedy, F.S. (1982) Catch rates of lobster traps baited with shorts, with notes on the effects of confinement. In Proc. Workshop on Florida Spiny Lobster Research and Management (Ed. by W.G. Lyons), p. 20. Fla. Dept Nat. Resources, St Petersburg, FL, USA. Labisky, R.F., Gregory, D.R., Jr. & Conti, J.A. (1980) Florida's spiny lobster fishery: an historical perspective. Fisheries, 5, 28±36. Lyons, W.G. (1986) Problem and perspectives regarding recruitment of spiny lobster, Panulirus argus, to the south Florida fishery. Can. J. Fish. Aquat. Sci., 43, 2099±106. Lyons, W.G. & Hunt, J.H. (1992) Catch rates of spiny lobsters, Panulirus argus, in traps equipped with escape gaps, and potential benefits to the south Florida fishery. Proc. Gulf Caribb. Fish. Inst., 40, 452±70. Lyons, W.G. & Kennedy, F.S., Jr. (1981) Effects of harvest techniques on sub-legal spiny lobsters and on subsequent fishery yield. Proc. Gulf Caribb. Fish. Inst., 33, 290±300. Lyons, W.G., Barber, D.G., Foster, S.M., Kennedy, F.S., Jr. & Milano, G.R. (1981) The spiny lobster, Panulirus argus, in the middle and upper Florida Keys: population structure, seasonal dynamics, and reproduction. Fla. Mar. Res. Publ., No. 38, 38 pp. Muller, R.G. & Hunt, J.H. (1992) A model of spiny lobster, Panulirus argus, dynamics in the Florida Keys. Abstract. 7th International Coral Reef Symposium, Aguna, Guam (abstract). Phillips, B.F., Pearce, A.F. & Litchfield, R.T. (1991) The Leeuwin Current and larval recruitment to the rock (spiny) lobster fishery off western Australia. J. R. Soc. Western Aust., 74, 93±100. Pope, J.G. (1972) An investigation of accuracy of virtual population analysis using cohort analysis. Res. Bull. Int. Commission Northwest Atlantic Fisheries, 9, 65±74. Powers, J.E. & Sutherland, D.L. (1989) Spiny lobster assessment, CPUE, size frequency, yield per recruit, and escape gap analyses. NOAA/NMFS/SFC/CRD-88/89-24, 75 pp. Robinson, R.K. & Dimitriou, D.E. (1963) The status of the Florida spiny lobster fishery. Fla. State Board Conserv. Mar. Lab. Tech. Ser., No. 42., 27 pp. Simmons, D.C. (1980) Review of the Florida spiny lobster resource. Fisheries, 5, 37±41. Zimmer-Faust, R.K., Tyre, J.E. & Case, J.F. (1985) Chemical attraction causing aggregation in the spiny lobster, Panulirus interruptus (Randall), and its probable ecological significance. Biol. Bull., 169, 108±18. Zuboy, J.R. (1980) The Delphi technique: a potential methodology for evaluating recreational fisheries. U.S. Department of Commerce, NOAA Tech. Memo NMFS-SEFC-19, 25 pp.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 11

The French Fisheries for the European Spiny Lobster Palinurus elephas H.J. CECCALDI Ecole Pratique des Hautes EÂtudes, Centre d'EÂtudes des Ressources Animales Marines (CERAM), Faculte des Sciences et Technique de Saint-JeroÃme, Ave. Escadrille Normandie-Niemen, F-13397, Marseille Cedex 20, France

D. LATROUITE Institut FrancËais de Recherches pour l'Exploitation de la Mer, Direction Ressources Vivantes, Ressources Halieutiques, BP 70, F-29280 PlouzaneÂ, France

11.1

Introduction

The European spiny lobster Palinurus elephas (Fabricius, 1787) = Palinurus vulgaris Latreille (called red spiny lobster or crayfish in English, and langouste rouge or langouste royale in French) has a wide geographical distribution in Atlantic and Mediterranean waters, along a large part of western European coasts, and on the north-western part of the coasts of Africa (Fig. 11.1). It is found in the Atlantic Ocean from the Hebrides to Morocco (Richie, 1912), in Scotland (Wilson, 1952; Ansell & Robb, 1977), Ireland (Gibson & O'Riordan, 1965; Culley & Driver, 1972; Mercer, 1973a), Wales, Devon (Bouvier, 1914) and Cornwall (Hepper, 1966, 1977) as well as in the western part of the English Channel, along the coasts of Brittany (Latrouite, 1992), Spain, Portugal (De Vasconcellos, 1960), to the occidental coasts of North Africa. Its southern limit in the Atlantic is Cape Bojador, in Morocco. This species is also distributed in the Mediterranean Sea, mainly in its western part, on the Spanish, French and Italian coasts, as well as in the Adriatic Sea (Gamulin, 1955), coasts of Greece (Moraitopoulou-Kassimati, 1972), Aegean Sea, Libya, and Sicily. It also occurs around the islands of Corsica (Campillo & Amadei, 1981; Marin, 1987), Sardinia (Santucci, 1926, 1928), Baleares and La Galite Island in Tunisia. In exploitable quantities, it occurs in several zones, mainly in western Ireland, around Cornwall (Hepper, 1967, 1977; Hunter et al., 1996) and Britanny (Latrouite & NoeÈl, 1997), along Portugal and Morocco and all around Corsica (Fig. 11. 1). As well as P. elephas, two other species of Palinurus from the north-east Atlantic can occasionally be found on French markets: P. mauritanicus and P. charlestoni. Palinurus mauritanicus, called in France langouste rose (pink spiny lobster), is distributed in the Atlantic from Ireland (Mercer, 1973a) to Senegal (Vincent-Cuaz, 1958; Maigret, 1980) and in the western Mediterranean. It is found from 40 to 600 m, but occurs in greatest abundance between 150 and 300 m. The main traditional fishing areas are located off Mauritanian coasts, where catches exceeded 3600 t in 1960. Overexploitation led to a drastic decrease in catches at the end of 1980, and the total closure of the fisheries by Mauritanian authorities in 1991. 200

French Fisheries for the European Spiny Lobster

Fig. 11.1

201

Distribution of Palinurus elephas.

In other areas, landings are generally low and the result of catches by netters and trawlers. For about 3 years there has been a small exploitation of P. mauritanicus within the Gulf of Biscay (Fig. 11.2). Another species, P. charlestoni, called the pink Green Cape spiny lobster or langouste du Cap Vert occurs around the Cape Verde Islands at depths ranging from 100 to 400 m (Forest & Postel, 1964). This species is endemic to the Cape Verde Archipelago (600 km west of Senegal). Annual catches are lower than 100 t.

11.2

Ecology

Palinurus elephas lives mainly in rocky bottoms, on hard substrates, between the seashore and a maximal depth of 150±160 m (see review by Hunter, 1999). Maximal abundance is observed between 50 and 100 m. It is more frequent in places where microcaves and natural protective holes are numerous, and in coralligeÁne facies.

202 Spiny Lobsters: Fisheries and Culture

Fig. 11.2 Distribution of Palinurus mauretanicus and P. charlestoni.

Where the two species P. elephas and P. mauritanicus exist at the same latitude, there are differences in their ecological niches, e.g. in depth. More detailed studies are necessary to understand better their distribution in the natural environment. On Corsican coasts, several sites favourable to concentration of P. elephas have been found, especially on the western side; juveniles seem to be located more frequently in Posidonia seagrass beds, at depths between 15 and 25 m (Marin, 1987). Although the low occurrence of P. elephas from the landings in winter has been hypothesized to be the result of an offshore migration (Mercer, 1973a) and of trawlers sometimes landing large hauls of rock lobsters during the autumn (Hunter et al., 1996), no scientific data support the idea of offshore±inshore migrations. The day-to-day movements of P. elephas seem to be limited and motivated by foraging, a change of shelter and reproduction. Its activity is mainly nocturnal.

French Fisheries for the European Spiny Lobster 11.3 11.3.1

203

Biological cycle Mating

Mating occurs within a period of 2±4 weeks after ecdysis, when the carapace has hardened. When the female is ready to spawn, it emits a specific stridulation which attracts males (Mercer, 1973a). This specific noise stops as soon as a male touches her with his antennae. Other males then cease to be attracted. The male turns the female on her back and mates with her by transferring the spermatophores, which are gelatinous and whitish, placing them near the genital orifices, close to the propodite of the third walking leg (P3) After several days, the female finds a quiet and safe place, generally a rocky shelter. The whole body, curved and terminated by the tail, acts as a receptacle for attachment of the eggs. These form an orange or deep yellow cluster, fixed on the setae of the pleopods. The whole process takes 1±2 h but the female does not move for 2±3 days. A female bearing such an egg cluster is said to be berried. 11.3.2

Maturity

In the Mediterranean, the first berried females are found in August and spawning lasts until October. Hatching occurs from January to March. In the Atlantic, the first berried females are found in August and the frequency rises steadily to reach a peak in November±December. Hatching begins at the end of March, is maximal in May and ends at the beginning of June. Thus, incubation requires 5 months in the Mediterranean and 7±8 months in the Atlantic. The size at which the females begin to carry eggs varies depending on the geographical zone where they are caught. The smallest berried females observed have a carapace length (CL) of 67 mm in the Mediterranean Sea (Marin, 1987) and in the Atlantic, 70 mm in Ireland (Mercer, 1973b), 90 mm in Cornwall (Hunter et al., 1996), and 92 mm in Britanny (Latrouite & NoeÈl, 1997). The mean size at functional maturity has been found to be 86 mm in the Mediterranean (Marin, 1987), and in the Atlantic 82 mm off Ireland (Mercer, 1973) and around 95 mm off Brittany (Latrouite & NoeÈl, 1997). It is not yet clear whether the difference between Ireland and Brittany reflects sampling problems or a real change that could have occurred between the 1970s and the 1990s. Most (>90%) of the mature females spawn every year. In the Atlantic, males are able to reproduce at a cephalothoracic CL of 90 mm, i.e. at a weight of 500 g. In Corsica, the mean size at first sexual maturity is 76 mm CL (Marin, 1987). 11.3.3

Fecundity

The number of eggs depends on the female's size: 120 000 for a female of 1 kg, and 250 000 for a female of 3 kg. About 10±30% of the eggs die and are lost during incubation.

204 Spiny Lobsters: Fisheries and Culture 11.3.4

Hatching and larval life

Hatching and release of the larvae occur over 3±5 days. At their liberation, the phyllosoma measure 3 mm. They remain in the plankton, often near the surface (Cunningham, 1891±92) for a period of several months. The larvae moult several times and finally reach the puerulus stage, a true swimming nektonic stage. Bouvier (1914) reported P. elephas larvae off Cornwall. The first benthic form, the post-puerulus, measures 3 cm, and is red±brown. This form presumably lives on rocky bottoms. It is the benthic recruitment form.

11.3.5

Biometric relationships

A mean relationship between total length (Lt), measured from the rostrum to the posterior margin of the telson, and carapace length (Lc) measured from the rostrum to the posterior margin of the cephalothoracic carapace, has been established separately in males and in females from France, Cornwall, Scotland and Ireland. Males: Lt ˆ 2:34Lc ‡ 48:8 mm Females: Lt ˆ 2:62Lc ‡ 40:6 mm A mean relationship between carapace length (mm) and weight (g) is as follows: Males: w ˆ 13  10 4 L2:856 c Females: w ˆ 26  10 4 L2:726 c

11.3.6

Growth

Growth has been studied in Corsica by Marin (1987) using tagging±recapture experiments. The following growth parameters have been established according to the von Bertalanffy equation: for males, Lct = 166 mm, k = 0.151 and to 0.348; for females, Lct = 136 mm, k = 0.185 and to 0.342. Thus, calculated CLs are 92 mm and 86 mm, respectively, for males and females, at the age of 5 years; 131 mm and 117 mm at the age of 10 years and 150 mm and 130 mm at the age of 15 years. No extensive study has yet been carried out to describe the growth of P. elephas in the Atlantic, which is colder but more rich in food than the Mediterranean Sea. It is likely that differences would be found.

French Fisheries for the European Spiny Lobster 11.4

205

Exploitation

FAO statistics for the year 1996 show that the total catches of Palinurus sp. were : Portugal, 139 t; France, 108 t; Ireland, 62 t; England and Wales, 7 t; Italy 312 t and Spain, 120 t. The figures are 20 t for Algeria, 26 t for Morrocco and 40 t for Tunisia (FAO Yearbook). It is likely from these statistics that P. elephas is the main species taken, although there may be some P. mauritanicus for Portugal, but it is also likely that none of these data is very accurate. In France, for instance, there is a noticeable difference between available landing statistics as edited by various official bureaux. A large quantity of the spiny lobsters is sold directly to private customers and restaurants. The estimates made in 1983 and 1984 were 188 and 206 t, respectively (Marin, 1987), corresponding to 83 and 88 t in official statistics. The same problems occur in the data for other countries as well, especially during the tourist season. Since about 1970, the catches of P. elephas by French fishing boats have been estimated at 200±400 t in the French market (Table 11.1). This species represents around 4% of the total value of marine Crustacea landed and sold in France. The highest landings of P. elephas are observed at Ajaccio and Bastia in Corsica for the Mediterranean Sea, and at Brest, Audierne, Morlaix and Le Guilvinec in Britanny on the Atlantic coast. Fishermen from other ports also fish the langouste rouge P. elephas: Concarneau, Loctudy, Camaret in Britanny, and at least Nice, Toulon and Marseille on the Mediterranean coast. In the Atlantic, the fishery for the red spiny lobster has been very important in the past (Cadoret et al., 1983). During the nineteenth century, several hundred sailing boats using pots fished in the Gulf of Biscay and off Britanny. By the beginning of the twentieth century, traditional fishing zones had been impoverished and the fishing boats were obliged to look for new sites to fish. A new type of specialized vessel was introduced: the vivier boat. Several tonnes of live crustaceans, lobsters and Table 11.1 Official total landings (t) of Palinurus elephas in France, caught in the Atlantic and the Mediterranean Year

Landings (t)

Year

Landings (t)

Year

Landings (t)

Year

Landings (t)

1960 1961

809 720

1969 1970

402 404

1978 1979

156 142

1987 1988

(?) 200 175

1962 1963 1964 1965 1966

699 498 457 437 401

1971 1972 1973 1974 1975

346 335 249 170 191

1980 1981 1982 1983 1984

156 195 250 187 188

1989 1990 1991 1992 1993

204 199 222 202 178

1967 1968

477 356

1976 1977

187 161

1985 1986

192 (?) 200

1994 1995

156 118

206 Spiny Lobsters: Fisheries and Culture spiny lobsters, may be maintained on board, and so fishing trips can be extended to several weeks. In 1902, fishing boats from Britanny reached the Scilly Isles, near Cornwall, and in 1905, the Spanish coast. They bought spiny lobsters from Spanish fishermen in the open sea. In 1906, they reached the coast of Portugal, in 1908, the coast of Morocco and, in 1935, the Island of La Galite, in Tunisia. In 1914, the port of Camaret, at the extreme west of Britanny, had as many as 170 specialized fishing boats, and in 1937, 209 boats fished from May to November in all the preceding zones. With other ports, such as Audierne, Le Conquet or Locquivy, the boats landed in all as much as 3200 t of red spiny lobsters plus European lobsters in 1928. The 1939±1945 war limited fishing, allowing the natural stocks to recover. Record landings of 3350 t occurred in 1947. Since then, they have diminished gradually and continuously. Until 1960, P. elephas was traditionally fished by means of cylindrical pots called in France casiers-barriques (barrel pots). They were made of laths of chestnut wood, with an entrance hole located in the upper part. Their more or less ovoid form gave them good stability on the rocky bottoms. These pots were still in use for fishing P. mauritanicus off the Mauritanian coast until 1991. Since 1985, a fleet of netters has developed to catch monkfish, Lophius piscatorius, turbot, Psetta maxima, rays or skates, Raja sp., and the red spiny lobster. They also catch, incidently, large Crustacea such as true lobster Homarus gammarus, crabs Cancer pagurus and spider crab Maia squinado. The nets are usually tangle nets (filets maillants) with stretched meshes of 320± 360 mm, or trammel nets (treÂmails) with stretched meshes of 260 mm inside and 800 mm outside. These nets are set in strings or sets of about 2 km length, and a fishing boat may lift about 100 km of nets each month. In general, the nets are left in the water for 72 h (3 fishing days). A longer stay leads to better spiny lobster catches as they are attracted by fishes caught in the nets. At present, the total number of these polyvalent netters is around 100 boats. The length of boats is 10±18 m. They are well equipped, with an echosounder to detect the most appropriate bottoms and all the other electronic equipment, especially navigation systems, to locate buoys with an accuracy of a few metres. They use power blocks for handling the nets. The annual landings for the French fishery in the Atlantic are estimated to be around 150±200 t. These catches are mainly composed of large size spiny lobsters: 25% weigh less than 1 kg, 25% weigh between 1 and 1.5 kg, 35% weigh between 1.5 and 2 kg and 15% weigh more than 2 kg. The landings show a seasonality, characterized by low rates from December to April, and higher rates from May to November, as in the example shown in Table 11.2. In the Mediterranean, in 1870, the Corsican fisheries had more than 200 fishing boats using pots and trammel nets. They landed around 150 t of spiny lobster per year. In 1948, there were 331 small fishing boats, landing 229 t. In 1960, the increase in local demand, induced by the development of tourism and the improvement of

French Fisheries for the European Spiny Lobster

207

Table 11.2 Seasonality of landings of Palinurus elephas in different months (relative landings month by month) Jan. 4

Feb. 4

Mar. 5

Apr. 7

May 9

Jun. 10

July 11

Aug. 11

Sept. 13

Oct. 11

Nov. 8

Dec. 6

fishing techniques, increased the fishing power of the fleet and led to a drastic diminution of landings, to as little as 50 t annually. Since 1980, the fleet has been composed of 150 fishing boats between 5 and 14 m, called pointus and equipped with sonar and, on the largest, power blocks. These boats use trammel nets. In the Mediterranean Sea and more precisely in Corsica, the nets used are of trammel nets type, locally called bistinari. The stretched mesh measures 125± 160 mm. Each boat lifts about 150 km each year (Marin, 1987). Nets are set in a series of strings, of a total length of 400±800 m and remain in the water for 2±4 nights. The CL of the animal fished is from 4 to 14 cm in males and 4 to 12 cm in females. The modal CL is 6±8 cm for both sexes (250 g). After a couple of years with high landings in 1983 and 1984 (owing perhaps to a higher recruitment), the annual catches have decreased and are estimated at 100 t. Fishing methods include two types of net: the use of pots is not frequent. Legal minimal size has been set at 18 cm total length in the Mediterranean Sea and 23 cm total length in the Atlantic.

11.5

Regulations

In European waters, there is no unification of regulations and the rules for fishing may vary within the different countries. In France, for the Atlantic coasts, the only common rule is linked to the length of spiny lobster caught. They have to reach a total length of 23 cm. In the Mediterranean coasts, that minimal limit is 21 cm. Around the Corsican coasts, where the principal fisheries of the Mediterranean Sea occur, the regulations delimit nine sanctuaries with a total area of 90 km2 and a closed season from the beginning of October to the end of February. The aim of these rules is to limit the fishing effort. The period of inactivity coincides with a lower commercial demand from the local market, directly linked with the tourist activities. During the same period, the females are carrying their eggs, which are incubating. Therefore, the rules are well accepted by the community of fishermen. French and British scientists have been asking the European Community to establish a common rule on all European coasts and to increase the minimal legal

208 Spiny Lobsters: Fisheries and Culture size. A traditional rule also prohibits the landing and sale of females carrying eggs; although not repealed, it is falling gradually into obsolescence.

11.6

Conclusions

The European spiny lobster has been fished on a large scale in the past. Its high value has led fishermen to fish this species extensively, up to the point of overexploitation. Fishermen are beginning to realize that resource management and new methods of exploitation are necessary to preserve the resource. Detailed studies of the genetics of different populations need to be developed in the near future in Corsica, the Mediterranean Sea and the Atlantic Ocean.

References Ansell, R.O. & Robb, B.L. (1977) The spiny lobster Palinurus elephas in Scottish waters. Mar. Biol., 3, 63±70. Bouvier, E.L. (1914) Recherches sur le deÂveloppement post-embryonnaire de la langouste commune (Palinurus vulgaris). J. Mar. Biol. Ass. U.K., 10(2), 179±93. Cadoret, B., Duviard, D., Guillet, J. & Kerisit, H. (1983) Ar Vag. Voiles au Travail en Bretagne Atlantique. Les Langoustiers. Editions de l'Estran, Douarnenez, France, 300 pp. Campillo, A. & Amadei, J. (1981) PremieÁres donneÂes biologiques sur la langouste de Corse. Palinurus elephas Fabricius. Rev. Trav. Inst. PeÃches Marit., 42(4), 347±73. Culley, M. & Driver, P. (1972) The crawfish industry of Ireland. Fish. News Int., 32±36. Cunningham, J.T. (1891±92) On the development of Palinurus vulgaris, the rock lobster or sea crayfish. J. Mar. Biol. Ass. U.K., 2, 141±50. De Vasconcellos, G.M. (1960) On the size relation and fecundity of the stock of spiny lobster, Palinurus vulgaris Latr., at the coast of Portugal. ICES C.M. 1960/219, 6 (mimeo). FAO Yearbook, Fisheries Statistics, Catches and Landings, 65, March 1989. Forest, J. & Postel, E. (1964) Sur une espeÁce nouvelle de langouste des iles du Cap Vert, Palinurus charlestoni sp. nov. Bull. Mus. Nat. Hist. nat. Paris, 36(1), 100±21. Gamulin, T. (1955) Contribution a la connaissance de l'eÂcologie de la langouste (Palinurus vulgaris Latr.) dans l'Adriatique. Acta Adriatica, 7(9), 3±17. Gibson, F.R. & O'Riordan, C.E. (1965) Palinurus vulgaris (L.), the crawfish, in Irish waters, 1962. Rapp. P.-V. Cons. Int. Explor. Mer., 156, 47±9. Hepper, B.T. (1966) Crawfish investigations in Cornwall. Report of investigations made in 1965. Shellfish Inf. Leafl. Fish. Lab. Conway, 5, 8 pp. (mimeo). Hepper, B.T. (1967) Observations on a crawfish Palinurus vulgaris Latr. tagging experiment off Cornwall in 1966. C.I.E.M., C.M. 1967/K, 13, 4 pp. (mimeo). Hepper, B.T. (1977) The fishery for crawfish, Palinurus elephas, off the coast of Cornwall. J. Mar. Biol. Ass. U.K., 57, 925±41. Hunter, E. (1999). Biology of the European spiny lobster, Palinurus elephas (Fabricius, 1787) (Decapoda, Palinuridae). Crustaceana, 72(6), 545±65. Hunter, E., Shackley, S.E. & Bennett, D.B. (1996) Recent studies of the crawfish Palinurus elephas in South Wales and Cornwall. J. Mar. Biol. Ass. U.K., 76, 963±83. Latrouite, D. (1992) La langouste rouge: fiche technique. Equinoxe, 38, (May), 29±30.

French Fisheries for the European Spiny Lobster

209

Latrouite, D. & NoeÈl, P. (1997) PeÃche de la langouste rouge Palinurus elephas en France. EleÂments pour fixer une taille marchande. Conseil Internat. Explor. Mer, I.C.E.S. C.M. 1997/BB, 13, 1±13. Maigret, J. (1980) Contribution aÁ l'eÂtude des langoustes de la coÃte occidentale d'Afrique crustaceÂs deÂcapodes, palinuridae. Etat des stocks sur les coÃtes du Sahara en 1979. Bull. Cent. Nat. Rech. OceÂanogr. PeÃches Nouadhibou, 9(1), 84±101. Marin, J. (1987) Exploitation, biologie et dynamique du stock de langouste rouge de Corse, Palinurus elephas Fabricius. TheÁse, Univ. Aix-Marseille, Faculte Sciences Luminy, France, 328 pp. Mercer, J.P. (1973a) Studies on the spiny lobster (Crustacea, Decapoda, Palinuridae) of the west coast of Ireland, with particular reference to Palinurus elephas Fabricius 1787. Thesis, University College, Galway, Ireland, 331 pp. Mercer, J.P. (1973b) Littoral and benthic investigations on the west coast of Ireland ± 11. (Section B: Shellfish investigations). The occurrence of Palinurus mauritanicus Gruvel, 1911, on the west coast of Ireland (Decapoda, Palinuridae). Proc. R. Ir. Acad., 73B, 445±9. Moraitopoulou-Kassimati, E. (1972) Distribution and fishing of the lobster Palinurus vulgaris and Homarus vulgaris in Greek seas. Hel. Ocean. Limn. Praktika Inst. Ocean. Fish. Res., 11, 179±95. Richie, J. (1912) The thorny lobster, Palinurus vulgaris, in the outer Hebrides. Scot. Nat., 93, 166. Santucci, R. (1926) Lo stadio natante e la prima orma postnatante dell'aragosta (Palinurus vulgaris Latr.) del Mediterraneo. R. Com. Talas. Italiano, Mem., 127, 3±11. Santucci, R. (1928) La pesca dell'aragosta in Sardegna. Rev. Com. Talas. Italiano, Mem., 136, 3±21. Vincent-Cuaz, L. (1958) La langouste rose de Mauritanie Palinurus mauritanicus Gruvel. Rev. Trav. Inst. PeÃches Marit., 22(3), 345±52. Wilson, E. (1952) The spiny or thorny lobster, Palinurus vulgaris Latreille in Scottish waters. Scot. Nat., 64(3), 151±7.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 12

The GalaÂpagos Spiny Lobster Fishery R.H. BUSTAMANTE Charles Darwin Research Station, GalaÂpagos Islands, Ecuador G.K. RECK Institute of Applied Ecology, University of San Francisco of Quito, Quito, Ecuador

B.I. RUTTENBERG School of Forestry and Environmental Studies, Yale University, New Haven, CT, USA

J. POLOVINA Honolulu Laboratory, Southwest Fisheries Science Center, National Marine Fisheries Service, NOAA, 2570 Dole Street, Honolulu, Hawaii 96822-2396, USA

12.1

Introduction

Fishing for lobsters has been an important part of the economy of the fishing sector of the GalaÂpagos Islands since the establishment of an export-orientated spiny lobster fishery at the beginning of the 1960s. From then until the early 1980s, spiny lobsters were harvested for export by divers operating from large vessels based in mainland Ecuador and carrying a variable number of dinghies (Reck, 1983). The primary diving gear used for commercial harvest of spiny lobsters in the GalaÂpagos is hookah gear. Hookah gear consists of a small air compressor in a dinghy (called a panga in GalaÂpagos) supplying air to up to two divers via long low-pressure hoses to depths of up to 15 m. Fuelled by an increase in tourism and immigration during the 1980s and the retirement of the last remaining large vessel in 1984, the lobster fishery grew rapidly at the local level (Reck, 1983). Initially, divers operated mainly during daylight hours, catching lobsters either by hand in their dens or by handheld harpoons. In the late 1980s, night diving became more important, as lobsters are more easily taken at night as they forage outside their shelters, and the use of Hawaiian slings also increased. No traps are used, as early trials proved unsuccessful. The fleet currently consists of approximately 145 small pangas (3± 5 m) and 47 mother boats (up to 15 m), all based in the GalaÂpagos Islands (Bustamante, 1998; Bustamante et al., in press). Most of the mother boats carry two to four pangas with them as operation units and carry several chest freezers on board, operated by a generator that keeps lobster tails frozen for up to 15 days (Fig. 12.1) (BarragaÂn, 1993; Campos, 1993). Lobster fishing in GalaÂpagos occurs within the boundaries of the GalaÂpagos Marine Reserve (GMR), a marine protected area created in 1986 that includes all of the waters and shorelines of GalaÂpagos (Fig. 12.2). Until as recently as 1989, there were few conflicts between the three prominent activities within the reserve: fishing, conservation and tourism. However, in recent years the conservation and tourism 210

The GalaÂpagos Spiny Lobster Fishery

211

Fig. 12.1 A typical GalaÂpagos mother boat with a panga tied to the stern, used in the spiny lobster fishery.

sectors have raised concerns over the ecosystem impacts of fisheries within the GMR, especially the lobster fishery and shark fishery. Management goals are complicated by the fact that the spiny lobster fishery has been the most consistent and significant source of income for local fishermen, accounting for more than 50% of annual revenues over the past few years (Bustamante, 1998; Bustamante et al., 1999). Fishery management has been so contentious in recent years that an attempt to close another lucrative benthic fishery, the sea cucumber fishery, prompted local fishermen to storm the headquarters of the GalaÂpagos National Park Service (GNPS) and the Charles Darwin Research Station (CDRS). Fishermen threatened conservation workers and some of the wildlife, demanding that the fishery be reopened (Camhi, 1995; Merlen, 1995). The event ended without serious incident, but tensions have remained between fishermen and conservationists, and only in the past year or so have meaningful discussions about management resumed (Heylings et al., 1998). After the sea cucumber fishery was closed, the fishermen returned to the spiny lobster fishery as a replacement for lost sea cucumber revenues.

12.2

Catches and species composition

The earliest records of lobster exports from Ecuador date from 1960, peaking at nearly 95 t in 1964, decreasing steadily to around 30 t by 1980, and fluctuating

212 Spiny Lobsters: Fisheries and Culture 2 Darwin Wolf

1 N Pinta

10 nautical miles

Genovesa Marchena 0

Santiago Fernandina Rabida

Santa Cruz ´ San Cristobal

´ Pinzon Isabela Santa Fe´ 1

~ Espanola Floreana 92

91

90

89

Fig. 12.2 Map of the GalaÂpagos archipelago.

erratically between 15 and 100 t during the 1980s and 1990s (Fig. 12.3). This time series shows three drastic decreases in exports from 1964 to 1977, 1989 to 1993, and 1995 to 1998. The GalaÂpagos lobster fishery has contributed around 92% of the national exports, and the correlation between registered landings in GalaÂpagos and national exports is highly significant (Rs = 0.92, p < 0.05). A large proportion of the coast of the Ecuadorian mainland is sandy shore and mangrove swamp, which are not suitable habitat for spiny lobster. Therefore, it is not surprising that the mostly rocky shores of GalaÂpagos harbour most of the lobster populations exploited in the national fishery. The GalaÂpagos lobster fishery harvests primarily two species of spiny lobster, Panulirus penicillatus (Olivier, 1791), locally called the red lobster, and P. gracilis (Streets, 1871), locally called the green or blue lobster. Both species are almost

The GalaÂpagos Spiny Lobster Fishery 120

213

Galápagos catches National exports

100

Frozen tails (mt)

80

60

40

20

0 1960 1963 1966 1969 1972 1975 1978 1981 1984 1987 1990 1993 1996

Fig. 12.3 Total Ecuadorian exports and GalaÂpagos catches of frozen tails of lobster expressed in metric tons (t). In 1995 two fishing seasons were allowed. Data compiled from Reck (1983), Central Bank of Ecuador (1988±1998), and P. Ospina, unpubl. data.

entirely exported as frozen tails and middlemen pay the same price for both species. There is also a small incidental catch of slipper lobster, Scyllarides astori (Holthuis, 1960), which is consumed locally. In the 1960s and 1970s, catches were fairly equally divided between the two species of spiny lobster (Reck, 1983), but in recent years the catch has been sporadically dominated by one species or the other (Table 12.1). Discussions with fishermen suggest that these changes might be principally due to interannual fluctuations in recruitment, and to a lesser degree to changes in fishing activities. The slipper lobster has always been a minor contributor to the fishery, generally not exceeding 15% of the total catch. Recent ecological studies (Hickman & Zimmerman, in press) confirm previous observations that the red spiny lobster, P. penicillatus, dwells in groups in caves with multiple entrances and on exposed and wave-beaten rocky shores, usually in shallow waters of less than 2 m (Holthuis & Loesch, 1967; George, 1972; Reck, 1983). It feeds primarily on sessile invertebrates (especially barnacles), algae, detritus, and small crustaceans and molluscs (Hickman & Zimmerman, in press). In contrast, the blue spiny lobster, P. gracilis, generally prefers depths greater than 2 m in the calm and murky waters of bays and coves, and is often found under or between rocks rather than in caves. Large individuals of this species are normally solitary and feed on sessile invertebrates and detritus (Holthuis & Loesch, 1967; Reck, 1983; Hickman & Zimmerman, in press). The slipper lobster S. astori ranges from shallow waters to

214 Spiny Lobsters: Fisheries and Culture Table 12.1 Contribution of each species of lobster to total catches between 1994 and 1998 Year

Catch (t)

P. penicillatus (%)

P. gracilis (%)

S. astori (%)

1994a 1995a 1996a

12.14 34.20 61.83

18.14 45.8 71.79

81.86 54.2 28.21

± ± ±

1997b 1998b

76.20 33.84

73.8 46.7

22.0 36.6

4.1 16.6

a

Values taken from Fisheries Observer Program of the Ecuadorian National Institute of Fisheries (unpubl. data). b Values from the CDRS-GNPS Fisheries Monitoring Program.

depths of over 20 m, often living solitarily in dead-end caves and large crevices (Hickman & Zimmerman, in press). The white sea urchin Tripneustes depressus is one confirmed prey species of the slipper lobster in captivity, but little is known about dietary composition under natural conditions (C. Martinez, unpubl. data). Catches in GalaÂpagos have fluctuated greatly in recent years, but since 1995 local landings have decreased steadily (Fig. 12.3). During the June±December season of 1997, the fishery harvested an estimated 76.2 t of frozen tails and exported 65.2 t, valued at US $1.2 million. In contrast, the July±February season for 1998 yielded almost 34 t, valued at US $0.6 million. This drop appears to be due to the low abundance of the red spiny lobster, P. penicillatus. Lobsters are currently caught either from boats using several pangas on trips that range from several days to a few weeks or by lone pangas on daily excursions from the main harbours (BarragaÂn, 1993; Campos, 1993). These two types of operation are difficult to compare because the nature of the fishing is different. Although both carry divers using hookahs, boats can fish at a greater number of sites, move quickly between them and operate during the night, while pangas fish during the day at one or a few sites close to the harbours (Bustamante, 1998; Bustamante et al., 1999). To account for these differences, fisheries monitoring studies have used two measures of catch per unit effort (CPUE): (1) kilograms of frozen tails per trip for large boats; and (2) kilograms of frozen tails per day for pangas (BarragaÂn, 1978, 1993; Reck, 1983; Campos, 1993; Correa, 1994). Analysed separately, the annual CPUE for both boats and pangas decreased between 1994 and 1998 (Fig. 12.4). CPUE for boats has decreased more than fourfold from about 900 kg/trip in 1994 to only 200 kg/trip in 1998, while CPUE for pangas has been halved over the same time period, from 30 kg/day to 16 kg/day. Since the data over the last few years indicate that trip length has not changed, the observed drop in CPUE for boats (as measured by kg/ trip) clearly demonstrates a downward trend. A reduction in the abundance of lobster due to overexploitation is probably responsible for the declines in both measures of CPUE.

1200.0

30.0

1000.0

30.0

800.0

24.0

600.0

18.0

400.0

12.0

200.0

6.0

0.0 1993

1994

1995

1996

1997

1998

215

CPUE Pangas (kg/trip)

CPUE Boats (kg/trip)

The GalaÂpagos Spiny Lobster Fishery

0.0 1999

Fig. 12.4 Annual values of catch per unit effort (CPUE) for boats (solid circles) and pangas (open circles) between 1994 and 1998.

12.3

Fishery distribution

Between 1975 and 1979, approximately 74% of the catch came from the waters around Isabela, the largest island in the archipelago (Reck, 1983). In recent years, however, the other islands have been harvested more intensively, the most important of which are San Cristobal, Darwin and Wolf, and Santa Cruz (Table 12.2). For the inhabited islands of Santa Cruz and San Cristobal, this increase is the result of a growth in the number of pangas unable to operate far from the home port. As the largest island, with nearly half of the coastline of the entire archipelago, Isabela still accounts for more than 30±50% of the total catch. As in the rest of the archipelago, the fishing population and the fishing fleet of pangas and mother boats have grown in the single port on Isabela, further increasing fishing pressure around this island.

12.4

Research and management

Most biological and fisheries research of lobsters in GalaÂpagos was conducted by G.K. Reck in the late 1970s and early 1980s. These studies investigated a range of ecological and biological questions, including reproduction, morphometry and growth estimates, population dynamics, spatial distribution and fisheries biology such as total landings, CPUE and production modelling (Reck, 1983, 1984). Since then, scientists from the Ecuadorian Institute of Fisheries have made fisheries reports only sporadically (BarragaÂn, 1978; Campos, 1993; Correa, 1994; MoraÂn, 1997). During the 13-year period from 1983 to 1996, no biological or ecological work was conducted on lobsters in GalaÂpagos. However, in early 1997 an intensive fisheries monitoring programme was initiated by the CDRS and the GNPS, the new administrator of the GalaÂpagos Marine Reserve, to generate current information on the use of marine resources and the state of exploited populations. As part of this programme, researchers collect biological samples and catch, effort, distribution and economic data on a daily basis at each of the three main fishing ports. To

26.31 0.77 0.01 0.98 0.04

Isabela S. Cristobal Darwin & Wolf S. Cruz Santiago EspanÄola Floreana Santa FeÂ

NK, not known; NR, not recorded.

71.85

NR

28.15

Total

NR NR NR

NK NK NK

S. astori

NR NR NR NR NR

13.90 9.14 0.88 2.18

18.03 6.61 21.12

P. penicillatus

Fernandina PinzoÂn RaÂbida

0.04

P. gracilis

Islands

1996

62 000

9229 5690 546 1374

27 488 4571 13 102

Total (kg)

16.68

1.13 1.51 0.46

11.03 2.56

P. gracilis

78.81

0.99 1.65 1.15

2.71

5.18 15.54 8.41 1.06

15.87 26.27

P. penicillatus

1997

4.50

0.53 2.84

0.01 1.12

S. astori

24 500

241 405 281

665

1675 4873 2173 259

6592 7335

Total (kg)

Table 12.2 Catches of lobster per island between 1996 and 1998 expressed as percentages of the total

The GalaÂpagos Spiny Lobster Fishery

217

complement the fisheries monitoring programme, the CDRS has initiated a number of studies on the basic population biology and ecology of the lobsters, including intensive sampling of size at maturity, fecundity, gonad development, growth estimates and dietary preference to update population parameters and provide the basis of future management. After the El NinÄo event of 1997/98, a recruitment pulse was observed in both P. penicillatus and P. gracilis, and cohorts have been followed to improve the estimates of growth parameters. The CDRS has also begun a few studies to address the role of spiny and slipper lobsters in benthic community structure. It has been suggested that increases in the abundance of some sea urchins observed over the past few years may be partially explained by the release from predation, as the slipper lobster appears to be a predator of at least one species of sea urchin, T. depressus. It is expected that in the coming years substantially more ecological information will be available for the management and conservation of lobsters in GalaÂpagos. Fisheries management has also been complicated in recent years. Before 1998, fishing in GalaÂpagos was controlled and administrated by a centralized national fishing authority based in Guayaquil, the main mainland port, and with only weakly empowered and supported regional staff in the GalaÂpagos. This situation created conflicts and uncertainties for both the local fishermen and the GNPS as the local conservation authority when illegal actions occurred within the supposedly protected marine reserve. Differences in goals and policies and the lack of clearly stated and generally accepted principles for the management and conservation of marine resources precluded interinstitutional co-ordination and co-operation. These factors, combined with remote decision making and ineffective or absent enforcement mechanisms in GalaÂpagos, resulted in an extremely weak management authority. Historically, management regulations have included a minimum legal size (to date 26 cm total length for both species of spiny lobsters) and prohibitions against taking gravid females (in force since the beginning of the 1970s), a legal fishing season within each year (4±7 months), bans on harpoons and spearguns, and restrictions against fishing at night (BarragaÂn, 1993). A compulsory certification system for lobster exports was also imposed on merchants and dealers. However, none of these restrictions was controlled or enforced. A size limit several centimetres below the legal size was imposed by market constraints rather than by governmental authority. The slipper lobster fishery could not be restricted because of opposition by local fishing co-operatives, despite indications that its population was under strong pressure as a result of limited recruitment capacity, and slipper is now the main lobster served at local restaurants. In 1994, owing to the strong decline in total catch, a 5-year closure was imposed on the fishery to allow stocks to recover, only to be lifted 18 months later as a result of pressure from local fishermen who were supported by the dealers. The reopened fishery included a total allowed quota (TAQ) system for the first time, in addition to other regulations still in place. Preliminary results seem to support the general impression that quota systems are effective only under management regimes more

218 Spiny Lobsters: Fisheries and Culture developed than in Ecuador. In March 1998, Ecuador passed the Special Law for GalaÂpagos (SLG) that gave control and enforcement of the fisheries within the GMR to the GNPS under a multi-institutional supervisory board, the Marine Authority. The GNPS simplified the complicated system of multiple regulations, maintaining regulations only on season, minimum size, and protection for gravid females during the 1998 fishing season. The TAQ system was eliminated because of a lack of compliance and enforcement. Demographic modelling will hopefully be used to define quotas in the near future (Polovina et al., 1993). For now, restrictions on fleet size, fishing season and fishing permits will be easier for the GNPS to control with its limited management capacity. Even with the new SLG there are no effective procedures to limit the number of fishermen in GalaÂpagos and this may create problems for effort-based fishery management in the near future. The decision-making process for fisheries also changed with the SLG. An advisory board of stakeholders (a `junta' comprising representatives from the fishing sector, tourist industry, local authorities and conservation interests) was formed to analyse available data and discuss broader management strategies for the lobster and other fisheries in GalaÂpagos. The SLG also instituted for the first time the principles of participatory and adaptive management for the sustainable utilization of marine resources within a marine protected area, the GMR (Heylings et al., 1998).

12.5

Summary

The spiny lobster fishery in the GalaÂpagos has averaged around 35 t in tail weight over the past 40 years, with considerable interannual variation around this long-term mean (Fig. 12.3). The interannual variation in total catch, together with the recent declines in catch rate, suggests that the fishery operates in a pulse fishing manner, fishing down irregular recruitment pulses over several years. This strategy may result in suboptimal biological and economic yields and risks recruitment overfishing. Further management of the lobster fishery needs to account for the conservation and tourism value of the nearshore marine ecosystem. Based on local knowledge of the fishery and drawing on approaches to resource management and species conservation that are appropriate within a marine protected area (Dugan & Davis, 1993; Bohnsack, 1994; Roberts, 1997, 1998a), a new approach to the management of the GalaÂpagos lobster fishery is being developed. This approach consists of three key components: (1) no-take areas; (2) a tight limited entry system; (3) harvest quotas. Since long-term data are still lacking, a number of studies designed to improve stock assessment and understanding of population dynamics is needed before effective management of the lobster fishery can take place. Of vital importance is a re-evaluation of population parameters such as growth, mortality, age at maturity and measures of recruitment before any modelling is applied. In addition, fully protected areas that contain significant unexploited stocks will hopefully allow exploited stocks to recover (Roberts, 1998b). No-take zones, as suggested by Roberts

The GalaÂpagos Spiny Lobster Fishery

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(1998a), will allow marine ecosystems to rebuild the community-level relationships that may be important for the management of all exploitable resources. The new SLG and Management Plan for the GMR have created a unique opportunity for real participatory management in a marine ecosystem on a large scale. However, the history of conflict in fishery management in GalaÂpagos will not make this an easy goal to achieve. True involvement of the fishermen in both decision making and monitoring to validate decisions through knowledge and experience will be a necessary component to the success of this endeavour.

Acknowledgements We wish to thank all those who have contributed to the collection of the lobster fisheries data. The senior author thanks the US Agency for International Development (USAID), the David and Lucile Packard Foundation, and the EU INCO for funding the Charles Darwin Research Station Fisheries Monitoring Program. Dr Jeffrey J. Polovina thanks the Fulbright Program for supporting his collaboration with researchers at the Charles Darwin Research Station.

References BarragaÂn, J. (1978) Informe general de la pesca y problemaÂtica pesquera de la provincia de GalaÂpagos. Informe especial, Instituto Nacional de Pesca, 25 pp.BarragaÂn, J. (1978) Informe general de la pesca y problemaÂtica pesquera de la provincia de GalaÂpagos. Informe especial, Instituto Nacional de Pesca, 25 pp. BarragaÂn, J. (1993) Observaciones sobre la biologõÂ a de la langosta roja Panulirus penicillatus, Oliver, en las islas GalaÂpagos. Rev. Cienc. Mar Limnol. Inst. Nac. Pesca, 3, 151±70. Bohnsack, J.A. (1994) Marine reserves: they enhance fisheries, reduce conflicts, and protect resources. NAGA, 17, 4±7. Bustamante, R.H. (1998) The artisanal fishing sector of the GalaÂpagos and the 1997 fishing Season. In: Galapagos Report 1997±1998 (Ed. by WWF-FN), pp. 25±9. Trama Publishers, Quito, Ecuador. Bustamante, R.H., Espinoza, E, Nicolaides, F., Murillo, J.C., Chasiluisa, C., Ruttenberg, B., Andrade, R., Torres, S., Toral, V., Barreno J. & PiuÂ, M. (1999). Fishing in the Galapagos Marine Reserve: a summary for 1998. In Galapagos Report 1998±1999 (Ed. by WWF-FN), pp. 43±9. Trama Publishers, Quito, Ecuador. Camhi, M. (1995) Industrial fisheries threaten ecological integrity of the GalaÂpagos Islands. Conserv. Biol., 9, 715±24. Campos, J. (1993) Informe sobre la situacioÂn actual de la langosta en la regioÂn insular y continental del Ecuador. Informe especial, Instituto Nacional de Pesca, Junio 1993, 15 pp. Correa, J. (1994) Informe sobre el recursi langosta en la regioÂn insular y continental del Ecuador. Informe especial, Instituto Nacional de Pesca, Julio 1994, 32 pp. Dugan, J.E., & Davis, G.E. (1993) Applications of marine refugia to coastal fisheries management. Can. J. Fish. Aquat. Sci., 50, 2029±42. George, R.W. (1972). South Pacific islands ± rock lobster resources. Report prepared for the South Pacific Islands Fisheries Development, 42 pp.

220 Spiny Lobsters: Fisheries and Culture Heylings, P., Cruz, F., Bustamante, R.H., Escarabay, M., Granja, A., Martinez, W., Hernadez, J., Jaramillo, C., Martinez, P., Piu, M., ProanÄo, P., Valverde, F. & Zapata, C. (1998) Participatory and adaptative management for the Galapagos Marine Reserve. In Galapagos Report 1997± 1998 (Ed. by WWF-FN), pp. 14±16. Trama Publishers, Quito, Ecuador. Hickman, C. & Zimmerman, T. (in press) Crustaceans of Galapagos. A field guide to the common barnacles, shrimp, lobsters, and crabs of the Galapagos Islands. In Sea Life of Galapagos Series. Sugar Sping Press, Lexington, KY, USA, 112 pp. Holthuis, L.B. & Loech, H. (1967) The lobsters of the Galapagos Islands (Decapoda: Palinuridae). Crustacean, PI VIII±IX, 12, 214±22. Merlen, G. (1995) Use and misuse of the seas around the GalaÂpagos Archipelago. Oryx, 29, 99±106. MoraÂn, G. (1997) Informe general sobre la pesca de langostas en las islas GalaÂpagos. Informe especial, Instituto Nacional de Pesca, 16 pp. Polovina, J.J., Haight, W.R., Moffit, R.T. & Parrish, F.A. (1993) The role of benthic habitat, oceanography, and fishing on the population dynamics of the spiny lobster, Panulirus marginatus (Decapoda, Panuliridae), in the Hawaiian archipelago. In Proceedings of the fourth International Workshop on Lobster Biology and Management, 1993. Crustaceana, 68, 203±12. Reck, G.K. (1983) The lobster fishery. In The coastal fisheries in the Galapagos islands, Ecuador. Descriptions and consequences for management in the context of marine protection and regional development. Doctoral dissertation, Kiel University, pp. 123±92. Reck, G. (1984) La pesca de langostas en las islas GalaÂpagos 1974±1979. Bol. Cient. Tecnol. Nac. de Pesca, VI, 3, 49±77. Roberts, C. (1997) Ecological advice for the global fisheries crisis. TREE, 12, 35±8. Roberts, C. (1998a) No-take marine reserves: unlocking the potential for fisheries. Marine Environmental Management Review of 1997 and Future Trends, 5, 127±32. Roberts, C. (1998b) Sources, sinks and the design of marine reserve networks. Ecol. Appl., S8, S160±4.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 13

The Spiny Lobster Fishery in Japan and Restocking M. NONAKA Tokyo University of Fisheries, 4-5-7 Kounan, Minato-Ku, Tokyo 108-8477, Japan

H. FUSHIMI Fukuyama University, Sanzo, Gakuen-cho, Fukuyama, Hiroshima 729-0292, Japan

T. YAMAKAWA Fisheries Research Institute of Mie, Hamajima, Shima, Mie 517-0404, Japan

13.1

Introduction

The spiny lobsters commercially fished along the coasts of Japan are Panulirus japonicus, P. longipes femoristriga, P. homarus homarus, P. penicillatus, P. ornatus, and P. versicolor. Of these six species, P. japonicus is the most widely distributed and abundant. Spiny lobsters play an important role in the fisheries of rocky coastal areas. Many studies and practical investigations to promote the increase of this resource have been undertaken in Japan. This chapter seeks to present the main achievements in this field, providing details not only of the most recent experiences, but also of early developments related to efforts to restock lobster in Japanese waters. These efforts may not be well known abroad and the authors hope that the following information will help to document these activities.

13.2 13.2.1

Phyllosoma Rearing of phyllosoma

Rearing of phyllosoma larvae to post-larvae and subsequently releasing them into the sea constitutes a direct method of increasing the lobster resource. It also provides valuable materials for the study of the early life cycle of lobsters. In Japan, research on spiny lobster began with the experimental hatching and rearing of the phyllosoma of P. japonicus. Hattori & Oishi (1899) conducted the first rearing experiments in Shirahama, Chiba Prefecture. Following these, several additional experiments were carried out, but without success in growing the newly hatched larvae. Nakazawa (1917) provided additional information on the ecology of wild phyllosoma larvae and puerulus. Oshima (1936), after making observations on the features of the mouth of the newly hatched phyllosoma, presented suggestions regarding feeding 221

222 Spiny Lobsters: Fisheries and Culture activity. Nonaka et al. (1958) were the first to succeed in obtaining a second moulted individual under rearing conditions by using Artemia nauplii as feed. Additional research was performed by Saisho (1962), among many others, and then Inoue (1978, 1981) succeeded in rearing phyllosoma until the last stage by feeding macroplankton, fish fry and other feeds in a flow-through rearing system. Kittaka (1988) first succeeded in completing the development of larval stages in a palinurid species, rearing the larvae of Jasus lalandii to the puerulus stage. Yamakawa et al. (1989) in the Fisheries Research Institute of Mie Prefecture, and Kittaka & Kimura (1989) at Kitasato University both succeeded in attaining the puerulus stage of P. japonicus from larvae hatched under laboratory conditions. In addition, the puerulus stage was successfully attained at the Tasaki Institute for Marine Biological Research in 1989, and by the Minami Izu Station of the Japan Sea-Farming Association (JASFA) in 1990. Thus, a period of almost 90 years elapsed between the initial research and the achievement of this goal. In the following period from 1989 to 1997, 327 individuals of pueruli were obtained from the newly hatched phyllosoma of P. japonicus in the Minami Izu Station of JASFA. Sekine et al. (2000) indicated by this result the variations in the duration, the number of moulting and the size of the last stage in phyllosoma stage in the rearing condition, and presumed that these variations would be in the natural environment. Additional studies related to the completion of the larval rearing of P. longipes femoristriga succeeded in the Fisheries Research Institute of Mie Prefecture in 1997 (Matsuda & Yamakawa, 2000), and of the slipper lobster, Ibicus novemdentatus and I. ciliatus by Takahashi & Saisho (1978).

13.2.2

Collection of phyllosoma

In Japan, no systematic studies related to large-scale collection of phyllosoma have been conducted, but many other lobster research reports of importance are available. Yokoya (1919) reported on two palinurid phyllosoma larvae found in the stomach of a tuna. Oshima (1942a) noted various developmental stages of phyllosoma larvae of two palinurid species among 23 individuals collected in Japanese seas. Two types differed from the classification of Gurney, and were defined as types E and F. Murano (1971), among 11 palinurid larvae in late stage of phyllosoma, reported five types including the two types reported by Oshima, and suggested that the F type of Oshima and his A type were P. japonicus. Nakamura (1974, 1975) described three types of larvae among 300 palinurid individuals from early to late stages of phyllosoma collected on the coast of Tokushima Prefecture, and suggested the possibility of collecting phyllosoma from along the coasts. Kanamori & Yoshimura (1987) also found three types of larvae from 24 individuals collected off Wakayama Prefecture. Nonaka et al. (1989) investigated the allometric growth of 190 palinurid phyllosoma larvae and presented a preliminary classification of the phyllosoma of the six species of spiny lobster distributed in Japanese seas.

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An analysis of the relation between the Kuroshio Current and the availability of the stock of P. japonicus has been performed by Oshima (1976). Sekiguchi (1985a) examined the arrival to the coast of phyllosoma larvae and presented hypotheses on their dispersion mechanisms. Sekiguchi (1985b) also reviewed up-to-date information on the biology of phyllosoma larvae. Recently, Yoshimura et al. (1999) caught 89 later stage form F phyllosoma and 43 free-swimming pueruli of P. japonicus off the south coast of Kyushu Island. They reported that the highest densities of the final phyllosoma larvae were observed in or near the Kuroshio Current, where highsalinity (34.8) water exists at depths below about 80 m, and that moulting to the puerulus stage also occurred in the same area.

13.3

Puerulus

As mentioned previously, Nakazawa (1917) first presented information related to the ecology of the puerulus stage. Kinoshita (1934) collected 34 pueruli by a lighting technique and reared them to moult stage PL4 while observing their growth and pigment changes. This appears to be the first study reporting the use of a lighting method for collecting pueruli. Oshima (1948) collected pueruli before the spawning season in April and suggested that newly hatched phyllosoma could develop into the puerulus stage within 1 year. This was the first time that the duration of the larval period of phyllosoma was estimated. Okada & Kubo (1948, 1950) conducted intensive collections of pueruli and compiled previous information, highlighting the diversity of collection areas. They also described the morphology of the puerulus and post-puerulus of P. japonicus. Nonaka et al. (1980) examined 294 pueruli and estimated the time and mode of appearance, and the size and duration of the puerulus stage. Since 1975 the collection of pueruli has become popular throughout Japan with the adoption of the Phillips collector (Phillips, 1972) among other types. Information related to pueruli of the other five species of spiny lobsters distributed in the coastal areas of Japan has been presented by Kubo (1950) for P. versicolor, by Tanaka et al. (1984) and Tanaka (1987) for P. longipes femoristriga, P. homarus homarus and P. penicillatus, and by Aoyama (1987) for P. ornatus.

13.4 13.4.1

Ecology of the stock Growth, migration and release of tagged individuals

The growth of P. japonicus has been estimated from carapace length (CL) distribution by Nakamura (1940) and Oshima (1942b) for individuals up to 2 years after the puerulus stage, and by Fushimi (1976a) for males up to 5 years and females up to 4 years. Kanamori (1988) has evaluated growth up to 10 years by a mathematical formula using data obtained from a tag-and-release study.

224 Spiny Lobsters: Fisheries and Culture Based on the simultaneous analysis of multiple length±frequency data sets in a time series (Yamakawa & Matsumiya, 1997), Yamakawa (1997a) estimated growth, age composition, and recruitment of the Japanese spiny lobster, and compared the estimated growth rates with those from the literature (Figs. 13.1, 13.2). Males grew more quickly than females and conspicuous seasonal growth fluctuation was detected for each sex. Growth fluctuated from year to year, which suggested the presence of a density-dependent process. Oshima (1935) described the seasonal migration and outlined aspects of the habitat of puerulus, post-puerulus and adult stages. Fushimi (1976a) reported the peculiar mode of habitat use by age groups and the distribution pattern of populations in zones containing communities of agar-agar seaweeds, Gelidium amansii. Nonaka (1982) found that populations of particular ages occupied different areas, and suggested the existence of a relation between this and the yearly fluctuation of catches. Tag-andrelease programmes began by attaching a tag in the abdominal muscle (Kinoshita, 1932), while Takayama (1939) developed a technique for inserting the tag into the

Fig. 13.1 Estimated age composition for the catch of male Japanese spiny lobster Panulirus japonicus at Wagu, Mie Prefecture, Japan, from the multiple length±frequency analysis (Yamakawa, 1997a, 1997b; Yamakawa & Matsumiya, 1997). Columns correspond to the fishing seasons (1990/91, 1991/92, 1992/93, 1993/94, and 1994/95) from October (upper) to April (lower). Vertical arrows connect modes of the 1st age group, the second age group, and the third age group, respectively. n, total number of individuals measured for each month.

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225

Fig. 13.2 Comparison of the estimated growth rate of the Japanese spiny lobster Panulirus japonicus reported in the literature (Yamakawa, 1997a). Upper, males; lower, females. The initial date for reckoning age was set at 1 August. Results are based on: (a) simultaneous analysis of carapace length frequency data sets (Wagu, Mie Prefecture); (b) re-analysis of the carapace length frequency data sets of Nakamura (1940) (Kominato, Chiba Prefecture); (c) modes in carapace length frequency (Misaki, Kanagawa Prefecture), (d±f) analysis of carapace length frequency data by Harding's graphical method (d, e, Minamiizu, Shizuoka Prefecture; f, Ohara, Chiba Prefecture); (g) tag±recapture (Ohara, Chiba Prefecture); (h, i) rearing experiment (Chiba Prefecture); (j) tag±recapture (Kinan, Wakayama Prefecture); and (k) monthly samples of individuals sampled via diving surveys (Banda, Chiba Prefecture).

226 Spiny Lobsters: Fisheries and Culture branchiostegal suture in the lateral portion of the cephalothorax. Later, Fushimi & Matsubara developed a technique for attaching a banok tag to the muscle located in the dorsal portion between the cephalothorax and the first abdominal segment (anchor tag technique) (Fushimi, 1984). This technique has subsequently been widely employed. According to the 31 reports of tag release from 1931 to 1982, the rate of recovery fluctuated from 1.0 to 22.1%. The longest time to recapture was 1280 days, and the longest migration distance registered was 34 km (Tanaka et al., 1988).

13.4.2

Catches

In Japan, spiny lobsters are caught on the pacific coast of southern Honsyu, Sikoku and Kyusyu. The average of the total annual catches of spiny lobsters in Japan from 1912 to 1976 is 1314 t, and the coefficient of variation is 13.9%, a fairly stable figure compared with other fishery products. The coefficient of variation per region is higher, but regional differences offset each other to maintain the rather low national coefficient (Nonaka, 1982, 1988). In addition, in the areas influenced by the Kuroshio Current, a relationship between the circulation pattern and the recruitment of post-larvae has been documented (Fushimi, 1976a). The catches during the fishing season in a fishing area are related to the structure of the population in that particular area and show marked temporal changes. Catches reach their maximum level just after the end of the closed spawning season, decrease towards the winter and increase again by spring. The amplitude of seasonal variation depends on the fishing area (Nonaka, 1982). Catches are mainly made using tangle nets, with some other methods as trawling nets, round trap, and diving (Table 13.1). The use of cage traps is very rare. The lobsters are captured with the net twice daily, at dusk and dawn (Kubo, 1962), to coincide with their activity rhythm. After statistical analysis of catch-effort data of a tangle-net fishery for the Japanese spiny lobster using an expanded DeLury's method, Yamakawa et al. Table 13.1 Rate of spiny lobster catch with tangle net in Japan Tangle net

Other methods

Year

Total catch (t)

(t)

(%)

(t)

(%)

1981 1982 1983 1984

1061 1153 1179 1119

959 1058 1099 1018

90.4 91.7 93.2 91.0

102 95 80 101

9.6 8.3 6.8 9.0

1985

1118

1007

90.1

111

9.9

Based on Nonaka (1988).

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(1994a) clarified that the catchability coefficient greatly varies according to such environmental factors as water temperature, lunar cycle and the intensity of ocean waves. The catchability coefficient becomes large in conditions such as when (1) the water temperature is high, (2) the phase of the moon is around the new moon, and (3) ocean waves are intense. The variation in the catchability coefficient is attributable to changes in the activity of lobsters according to the fluctuation of the environmental factors. As for the statistical models for analysis, the negative binomial model was optimal, adequately reflecting the distributional nature of spiny lobsters in the field, which shows a marked degree of aggregation, coupled with other features in the fishing activity (Yamakawa et al., 1994a). Moreover, Yamakawa (1997b) simultaneously estimated the stock size by year, age and sex, catchability coefficient, and the selectivity curve of the tangle-net fishery using a statistical catchat-age analysis with auxiliary information on separability, which treats the multicohort analysis (VPA) and the expanded DeLury's method in a united form. The estimated selectivity curve indicates that recruitment commences at around 40 mm CL, then the selectivity greatly increases from 50 to 60 mm. The difference in recruitment rate by sex or year can be consistently explained by the interaction between the size selectivity of the gear and the difference in growth rate for each group by sex or year (Yamakawa, 1997a). Thus, the variation of catch per unit effort (CPUE) in a fishing season of the Japanese spiny lobster (Fig. 13.3) can mostly be described in a model using integrated information on the shift in stock density of each cohort according to the progress of fishing, changes in the activity of lobsters according to the fluctuation of the environmental factors, size selectivity of tangle nets, growth of each cohort, and the distributional nature of lobsters.

13.4.3

Habitat

During the daytime, spiny lobster hide usually in fissures and crevices of the rocky bottom, and shores with such shelter are better fishing grounds. According to the results of experiments conducted in a pond to investigate the habit of shelter selection, lobsters gather selectively in artificial shelter and pond corners depending on the density of lobsters and the size and construction of shelter (Nonaka, 1966). This hiding behaviour contributes to the establishment of fishing areas in artificial embankments or rocky beaches (Nonaka, 1968; Fushimi, 1976b).

13.5 13.5.1

Restocking Recruitment and catches

Rearing to post-puerulus has become a reality, but projects incorporating the release of artificially reared post-puerulus may not be feasible for a long time.

228 Spiny Lobsters: Fisheries and Culture

Fig. 13.3 Catch-effort data from tangle-net fishery for Japanese spiny lobster at Wagu, Japan, through one fishing season from October 1990 to April 1991, applied for the analysis by the expanded DeLury's method (Yamakawa et al., 1994b). (a) Daily fishing effort; (b) CPUE for each day ( ) and their 1-week moving average (ÐÐÐÐ); (c) water temperature at 30 m depth; (d) lunar cycle (l, new moon; , full moon); and (e) intensity index of ocean waves.

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229

In each prefecture of Japan the minimum size of spiny lobsters for capture is restricted by fishery regulations (Table 13.2). Therefore, netted individuals that have not attained the minimum body length are returned to the sea. The relationship between the appearance of puerulus stage and the catches will now be discussed. According to Fushimi (1976a), there is a relationship between the number of juvenile lobsters caught per year in Irozaki, located at the tip of the Izu Peninsula, and the distance between this site and the central Kuroshio Current (Fig. 13.4). This suggests a relationship between the number of pueruli recruited and the location of the stream axis of the Kuroshio Current. Accordingly, when the Kuroshio flows nearer to Irozaki the recruitment of pueruli is high, but when the Kuroshio withdraws from Irozaki recruitment is low. According to records of repeated collections of pueruli in the same areas, pueruli are intermittently collected (Fig. 13.5); thus, they appear to Table 13.2 in Japan

Local regulations on closed season (ÐÐ) and body size in spiny lobster fisheries Month

Prefecture

Apr.

Chiba Tokyo Ogasawara Kanagawa Shizuoka Mie Wakayama

Miyazaki Kagoshima Fjukuoka Saga

ÐÐ

Nagasaki Kumamoto Okinawa

ÐÐ

ÐÐ ÐÐ

ÐÐ

Sept.

Limiting size (cm)

ÐÐ ÐÐ ÐÐ

ÐÐ ÐÐ ÐÐ

BL 13 BL 13 BL 22a BL 13 BL 13 CL 4.2 BL 15

ÐÐ ÐÐ ÐÐ ÐÐ

ÐÐ ÐÐ ÐÐ ÐÐ

ÐÐ ÐÐ

ÐÐ ÐÐ ÐÐ ÐÐ

ÐÐ ÐÐ ÐÐ ÐÐ

ÐÐ ÐÐ ÐÐ

ÐÐ ÐÐ

Jun.

Jul.

ÐÐ ÐÐ

ÐÐ ÐÐ

ÐÐ

ÐÐ ÐÐ ÐÐ ÐÐ

ÐÐ ÐÐ ÐÐ ÐÐ

ÐÐ ÐÐ

ÐÐ ÐÐ ÐÐ ÐÐ

ÐÐ ÐÐ ÐÐ ÐÐ ÐÐ ÐÐ ÐÐ

ÐÐ ÐÐ ÐÐ

Tokushima Kochi Ehime Ohita

a

May

Aug.

BL BL BL BL

13 13 15 20

ÐÐ ÐÐ ÐÐ ÐÐ

BL BL BL BL

15 13b 20 15

ÐÐ ÐÐ

BL 15 BL 20 BL 18c

For P. longpies/penicillatus/versicolor/omatus. For P. japonicus/penicillatus/omatus/versicolor/longipes. c For P. japonicus/omatus/versicolor. Others for P. japonicus. BL, body length; CL, carapace length. b

Remarks

230 Spiny Lobsters: Fisheries and Culture

Fig. 13.4 Relationship between the distance from Irozaki, Japan, to the central stream of the Kuroshio Current and the abundance of juvenile Panulirus japonicus.

Fig. 13.5 Variation in the number of puerulus stage of Panulirus japonicus collected in southern Izu Peninsula, Japan, by the Minami Izu Station of the Japan Sea-Farming Association. (Collections were made year round, but individuals could not be caught before 15 June or after October.)

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be distributed in small groups. The number of collected individuals increases from the appearance of the new moon to the first quarter of the moon, and decreases after this time until the appearance of the full moon. However, even in these periods, sometimes pueruli cannot be collected (Ichiki et al., 1976). These observations are of importance for the capture of pueruli, and indicate that intermittent collections may not be appropriate for the estimation of the abundance of pueruli throughout the year.

13.5.2

Artificial reefs

Creation of fishing reefs It is well known that spiny lobsters gather in sunken ships. This is due to the typical behaviour of the lobsters, which hide in dark places during the day. Because of this, laying structures imitating lobster habitats may lead to the formation of fishing grounds. This assumption is supported by the results of a survey conducted by the Japanese Research Group of Fisheries Engineering (1976), where the predominant species to be gathered in coastal embankments was the spiny lobster. Function of artificial reefs Research on the creation of spiny lobster fishing grounds through the utilization of concrete blocks began in 1933 in the Shizuoka Prefectural Fisheries Experimental Station (1934). In the Mie Prefectural Fisheries Experimental Station, artificial reefs were built with concrete blocks for spiny lobster and abalone, and their effectiveness was evaluated (Suguri et al., 1966). Nonaka (1968) reported the use of stone beds and piers in communities of agaragar seaweeds as fishing grounds for the spiny lobster. Oshima (1976) indicated that for every 100 m3 of piers made of piled rocks, the annual catches of spiny lobster may be between 111 and 331 kg, and that it could take 2±3 years to recoup the expenses for bank construction. Fushimi (1976b) reported the harbour banks themselves can be the fishing grounds of spiny lobsters, and that not only did these supply habitats for adult lobsters but, in some places, they could also modify the current conditions. In this case, the banks promote the attachment of pueruli in a similar way, as in the project for the enhancement of coastal fisheries resources described below. artificial reefs function as shelters in which spiny lobsters gather unless usually dispersed. Thus, it can be said that artificial reefs themselves serve as fishing grounds. However, in terms of fisheries, there is no actual increase in the population, because commonly dispersed lobsters represent the supply source for the artificial reefs. From this point of view, further studies need to be carried out before general conclusions can be reached. Nevertheless, artificial reefs increase the yield of lobsters even in usually poor fishing grounds, and thus are extremely advantageous for the spiny lobster fishery.

232 Spiny Lobsters: Fisheries and Culture Enhancement of coastal fisheries resouces The project for the enhancement of coastal fisheries resources in Japan was initiated in 1976 with the ultimate aim of improving fishery production. Part of this project seeks to enhance spiny lobster resources by improving the conditions for recruitment of wild pueruli. At present, this project is being executed in more than 10 different places in eight prefectures. Each location consists of a fishing ground of about 100 ha and has a budget of hundreds of millions of yen. The project involves the setting of concrete blocks of different shapes on stone beds (Fig. 13.6). The large scale of this project should result in the concentration of lobsters and finally in the establishment of fishing grounds. Furthermore, after the creation of fishing grounds, the management of the fishery is to be carried out through appropriate regulations. The primary purpose of the project is to promote the settlement of pueruli. Thus the basic strategy is to collect the puerulus approaching the coast. The forms or places for gathering pueruli in Japan can be classified as follows: 1. 2. 3. 4.

sea surface at night (with or without lighting) in pearl oyster or common oyster rafts, floating cages used for fish culture, or other objects close to the surface midwater collectors and hand trawling areas of agar-agar, eelgrass or other species, and bottom collectors

Fig. 13.6 Example of a project for the enhancement of coastal fisheries resource of spiny lobster Panulirus japonicus.

The Spiny Lobster Fishery in Japan and Restocking 5. 6. 7.

233

tidal pools, encavated ponds, or other places with stagnant water (Tanaka et al., 1988) phorad holes in rock faces, predominantly of the species Lithophaga curta (Yoshimura & Yamakawa, 1988; Yoshimura et al., 1994; Norman et al., 1994) sandy bottoms (Matsuda et al., 1992).

These collection places are diverse in nature and water depth. From this, it can be conjectured that at the time of settlement, pueruli approaching the coast stick to a suitable object, or may sink to the sand if appropriate objects are not available. Excluding collection at the sea surface, the common characteristic of the collection places is the lack of current. The project hypothesizes that if an obstacle of considerable dimensions is placed on the sea bottom, then fluctuating compressions will occur against the current, so that the currents surrounding the obstacle may be disturbed in such a way as to provide the cue to the settlement of pueruli. The effectiveness of the project can be evaluated by examining the number of pueruli settled. However, this may be a difficult approach. Nonaka & Kageyama (1981) determined effectiveness by comparisons of the variation in occurrence of post-puerulus near the project area, and by surveying the increase in post-puerulus inside the project area.

13.6

Fisheries management

Spiny lobsters are highly sedentary resources. Therefore, spontaneous fisheries management plans by fishermen have been conducted at each locality in Japan from old times, based on negotiation for management measures, formation of agreement and mutual surveillance between fishermen. Management measures at present are considerably diverse, e.g. establishment of closed season or closed areas, limitation for catchable size, introduction of various constraints for gear (type of nets, mesh size, thickness or quality of the net yarn, number of nets), total fishing recess, fishing recess around the new moon, shortening of the fishing season, relocation of closed areas, rotation system of fishing grounds, and release of berried females or small individuals. The type of management measures in practice, cause of introduction and the process of establishment vary between different localities. Some representative management measures are detailed below.

13.6.1

Closed season

In Japan, closed seasons and body or carapace length limitations are established in all 17 prefectures operating spiny lobster fisheries (Table 13.2) for protecting the spawning stock. The closed seasons are designed for reproductive seasons, which usually start earlier in the south than in the north. The regulations on body and carapace lengths are arranged on biological minimum (Table 13.2), which tend to be larger in the south than in the north.

234 Spiny Lobsters: Fisheries and Culture 13.6.2

Closed areas

When some part of a fishing ground is kept closed to fishing, the spiny lobster density in that area gradually increases. The closed area of Kominato Marine Biological Station of the Tokyo University of Fisheries (formerly Imperial Fisheries Institute) was established in 1937, and catches in that area have been recorded since July 1936 (Oshima, 1962; Yamakawa & Nonaka, 1988). According to these data, the density of spiny lobsters in the closed area, measured by the catch in 20 tangle nets (each net about 45 m long), became saturated 5±15 years after the establishment (Table 13.3) and the CPUE in that area became 4.6±7.9 times higher than that in the standard fishing grounds. Thus, population density in the closed area increased owing to the prohibition of fishing. Closed areas like those mentioned above have been established in random locations within fishing grounds and function as resource reservations, while at the same time they can be exploited collectively to raise resources for common purposes. 13.6.3

Relocation of closed areas

Fishing grounds are divided into different areas, some of which are closed to fishing or exploited in rotation. Closed areas are reopened only a few years later, so that at any one time part of the fishing ground remains closed. This approach has been practised in two fishing villages in Mie Prefecture, Sugari and Nishiki, since 1934, and details of the initial report (Oshima, 1962) are presented in brief below. The fishing ground of Sugari was divided into seven areas, and in each year since 1934 different areas started a cycle of prohibition of fishing for 2 years followed by permission for 3 years. CPUE after the reopening of the closed Table 13.3 Lobster population density in the closed area of Kominato Population densitya Year

Years after prohibition

1936 1937

0 1

± 9

1938 1939 1940 1951

2 3 4 15

24 61 106 153

± ± ± 24.4

± ± ± 6.2

1952 1957

16 21

132 81

28.6 10.3

4.6 7.9

a

Closed area (A)

Fishing ground (B) ± ±

Population density is shown as number of individuals captured per 20 tangle nets.

A/B ratio ± ±

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235

areas for fishing and that of the ordinary areas not subjected to relocation are shown in Table 13.4. The CPUE of a relocated area is 2.0±3.9 times higher than that of an ordinary fishing ground (except for 1937 when operated days were scarce). Thus, population density appears to increase owing to the prohibition of fishing. In area A, in the third year after the opening of fishing, catches declined to half of the first year, showing that population density is reduced with continuous fishing. In Nishiki, the fishing ground was divided into 10 areas and the relocation procedure was employed as in Sugari. Table 13.5 shows the effectiveness of the relocation in terms of the average catches. As in Sugari, in the first year after the opening of fishing, the CPUE of relocated areas was 4.2 or 2.8 times as high as that of an ordinary fishing ground. These results also show an increase in population density owing to the prohibition of fishing. An evaluation of the relocation effects in Nishiki in 1950 exhibited similar results (Oshima, 1962). It must be mentioned, however, that in the case of the relocation of closed areas in Sugari and Nishiki, the numbers of boats and tangle Table 13.4 Effectiveness of relocation of closed areas in Sugari CPUE (kg per boat per night)a Area (ha)

1934

A (6.6) B (8.3) C (6.6)

PF ± ±

D (6.6) OFGc Daysd

± ± ±

b

1935

1936

1937

1938

PF PF ±

20.9 PF PF

19.1 28.9 PF

8.6 12.4 14.6

± ± ±

± 5.3 42

PF 1.2 6

PF 4.4 22

a

Data available for four areas only. Prohibition of fishing. c Ordinary fishing ground. d Days of operation. b

Table 13.5 Effectiveness of relocation of closed areas in Nishiki CPUE (kg per boat per night)a Area A B OFGc Daysd a

1934 PF ± ± ±

b

Data available for two areas only. Prohibition of fishing. c Ordinary fishing ground. d Days of operation. b

1935

1936

1938

PF PF ± ±

9.6 PF 2.3 55

± 5.4 1.9 73

236 Spiny Lobsters: Fisheries and Culture nets, as well as the operation period, stocking of post-puerulus and other parameters, were equally controlled. Although the contribution of each of these factors cannot be estimated separately, the observed improvements have to be considered to be the result of the fishing prohibition. In the case of the 2 years of prohibited fishing, a catch revenue three times higher than that of an ordinary fishing ground will be required during the first year of the reopening to justify the relocation.

13.6.4

Total fishing recess

Total prohibition of fishing for spiny lobster for one or more years was practised in the prefectures of Wakayama and Nagasaki as a strategy against the decrease in lobster catches (Oshima, 1962). Unfortunately, this practice was not continued thereafter because of financial circumstances rather than as a result of its effectiveness. In Asaraiki, Wakayama Prefecture, catches declined from 2.6 t in 1914 to 0.8 t in 1917. From 1918, a total fishing recess was declared for a period of 3 years. This fishing recess resulted in a significant accumulation of lobster, then fishing was reopened 1 year later (1919). These results indicated a substantial increase in catches (Table 13.6, Fig.13.7). After the reopening, the net standards were restricted and the number of nets used per person was limited to 42%. The effectiveness of this fishing recess was so remarkable that the practice was also adopted in neighbouring fishing villages and practised again in Asaraiki. From these data, it is important to observe the considerable decrease in catches in Shibara in 1922 and in the other two neighbouring fishing villages after fishing recesses. Such decreases contrast with the stable catches observed in Asaraiki after the first recess (1919±1923), when the

Fig. 13.7 Effectiveness of total fishing recess in Wakayama Prefecture, Japan. Symbols indicate catches for ( ) Asaraiki, (9) Shibara, (4) Hiki, (5) Satoro. Average and range of catches were not improved by fishing recess. Dashed lines indicate a period of fishing recess.

The Spiny Lobster Fishery in Japan and Restocking

237

restrictions on fishing effort mentioned above were imposed. The unexpected reduction in catches in the other areas may therefore be due to the lack of restrictions of fishing effort. Unfortunately, there is no further information on the fishing processes in other areas. From 1933 to 1941, fishing recesses of 2±3 years were established in eight different areas of Nagasaki Prefecture. Studies conducted at that time reported an increase of three times the usual catches, but no detailed data were presented.

13.6.5

Management model

Most of the management measures described above were spontaneously conducted by fishermen based on their experiences in each locality. In recent years, the effectiveness of the management measures has been discussed based on scientific management models, and some gaps between optimal and actual measures have been presented. Yamakawa (1997a) showed the necessity of raising the size limit for catch by a large margin in each locality in Mie Prefecture after close examination of the optimal utilization of recruited stocks. A management model based on the optimal in-season allocation of fishing effort considering the shifts in the market price, catchability coefficient, operating costs, etc., was presented, and also an optimal fishery model was proposed, which aims to combine the effective utilization of the recruited stock and the reproductive management, introducing a concept of the economic value of the spawning stock (Yamakawa, 1997b). In relation to the size selectivity of the gear, Mie Prefecture (1993, 1997) examined the changes in the size and number of the entangled lobsters through test operations using different types of tangle net (single nets or trammel nets) with different mesh size. The results indicated that single nets should be used instead of trammel nets and the mesh size should be enlarged for desirable management. Furthermore, a management model based on a manipulation of the operation areas was proposed (Tsuiki et al., 1999), utilizing the fact that small individuals inhabit shallower waters more abundantly. More detailed scientific examination should be conducted to clarify the effectiveness and the mechanism of the traditional management measures based on the establishment of closed season or areas, introduction of fishing recesses, etc.

13.7

Problems of restocking

The direct method for the restocking of spiny lobster is to rear larvae to postpuerulus and then release them into the sea. Even though it is now possible to rear lobsters successfully to the post-larval stage, it may still require a long time before mass production can be established. Considering that restocking may temporarily increase the catches, spiny lobsters possess extremely good characteristics from an ecological point of view. The most

238 Spiny Lobsters: Fisheries and Culture Table 13.6 Effectiveness of total fishing recess in Wakayama Prefecture Production (kg per year) per fishing village Shibara

Hiki

Average catcha

Year

Asaraiki

Satono

1914 1415 1916

2625 2138 975

± 2220 1058

± ± ±

± ± ±

1917 1918 1919 1920 1921

788 FRb 6079 6191 5449

709 1241 1646 2546 2175

784 930 1181 FR 6495

458 536 465 1391 1954

685 902 1097 1969 2065

1922 1923 1924 1925

5310 4710 FR FR

2700 1946 FR 6431

2115 1598 FR 2783

FR 4170 1725 713

2408 1722 (1725) (713)

1926

6405

2786

848

±

(848)

(2625) 2179 1017

a

Data from areas not affected by fishing recess. Single data are indicated within parentheses. FR, fishing recess.

b

important characteristic is that they select habitats. This behaviour makes the creation of fishing grounds effective. In this regard, two problems are considered, one regarding the resource and the other its economics. Regarding the resource issue, the creation of fishing grounds leads to the gathering of otherwise widely distributed lobsters which constitute the total fishery resource. Thus, increased fishing pressure on these populations may occur, with potential damages on resource maintenance. In order to solve this problem, further studies related to the resource structure need to be undertaken. The other problem is related to the economics: feasibility of the balance between investment and catch should be considered. At present, there are no criteria on which to base a solid analysis of the problem. The quantity of lobsters that gather in an artificial fishing bank depends on the interaction between lobster density and the availability of habitats in that area. Thus, the potential effectiveness of artificial fishing banks cannot be properly evaluated without information on these aspects. Besides continuation of research work on such aspects, efforts should be devoted to reorganizing the information already available. In any case, it can be said that knowledge on the structure and distribution of the resource is vital. An increase in the supply of pueruli should be the primary consideration for the restocking of spiny lobster. it is necessary to bear in mind the existence of some pueruli which, although approaching the coast, fail to recruit and join the resource. The large-scale project for the enhancement of coastal fisheries resources in Japan

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mentioned above has addressed some of these problems, but its effectiveness is still not completely solved. At present, it is not even possible to estimate the quantity of pueruli approaching the coast every year. In this regard, a study on P. cygnus may be a useful and encouraging reference. In addition, research institutes in Japan such as the Izu Branch of the Shizuoka Prefectural Fisheries Experimental Station (Aoyama, 1983), the Minami-Izu Station of the Japan Sea-Farming Association (Fig. 13.5), the Fisheries Research Institute of Mie, Tokushima Prefectural Fisheries Experimental Station, Kochi Prefectural Fisheries Experimental Station, and Seikai National Fisheries Research Institute have began systematic year-round sampling of pueruli, which may help to elucidate this problem. Furthermore, knowledge of the distribution of newly settled pueruli in the fishing ground would be valuable for restocking purposes, but this will require further studies.

References Aoyama, M. (1983) On puerulus collected through 1982. Izu Bunjo Dayori, 212, 13±14 (in Japanese). Aoyama, M. (1987) Puerulus larvae and early juvenile stages of the ornate spiny lobster, Panulirus ornatus (Fabricius). Bull. Shizuoka Pref. Fish. Exp. Stn, 22, 31±8 (in Japanese). Fushimi, H. (1976a) Ecological contribution to the natural population of Japanese spiny lobster, Panulirus japonicus, in the southern coast of the Izu Peninsula. Fish Eng., 12(2), 21±6 (in Japanese). Fushimi, H. (1976b) Artificial banks serve as habitat for the Japanese spiny lobster, Panulirus japonicus. Fish. Eng., 13(1), 9±16 (in Japanese). Fushimi, H. (1984) Problems related to the resource enhancing ground for Panulirus japonicus and the releasing into the sea of Penaeus japonicus ± a review of fishery engineering studies. Fish. Eng., 20(2), 59±67 (in Japanese). Hattori, T. & Oishi, Y. (1899) Experiments related to the artificial propagation of Panulirus japonicus Gray in Shirahama. Rep. Fish. Inst., 1(1), 76±131 (in Japanese). Ichiki, T., Tanemura, K., Tominaga K. & Shiokawa, T. (1976) A catching technique and ecological aspects of puerulus larva and early juvenile of Japanese spiny lobster. Fish. Eng., 12(2), 31±6 (in Japanese). Inoue, M. (1978) Studies related to the cultured phyllosoma larva of the Japanese spiny lobster, Panulirus japonicus: I. Morphology of phyllosoma. Bull. Jpn Soc. Sci. Fish., 44, 457±75 (in Japanese). Inoue, M. (1981) Studies on the cultured phyllosoma larvae of the Japanese spiny lobster, Panulirus japonicus (v. Siebold). Special Rep. Kanagawa Pref. Fish. Exp. Stn, 1, 1±91 (in Japanese). Japanese Research Group of Fisheries Engineering (1976) Report of observations on the aggregation of aquatic life on artificial coastal constructions. Fish. Eng., 13(1), 29±42 (in Japanese). Kanamori, K. (1988) Population estimation and fishing management of the spiny lobster in Kinan area, Wakayama Prefecture. Ann. Rep. Wakayama Pref. Fish. Exp. Stn, 1986, 109±209 (in Japanese). Kanamori, K. & Yoshimura, K. (1987) Palinurid phyllosoma collected off shore of Shiono Misaki. Ann. Rep. Wakayama Pref. Fish. Exp. Stn, 1985, 186±95 (in Japanese). Kinoshita, T. (1932) Propagation of the spiny lobster, Panulirus japonicus (v. Siebold). Bull. Jpn Soc. Sci. Fish., 1, 237±40 (in Japanese).

240 Spiny Lobsters: Fisheries and Culture Kinoshita, T. (1934) Studies related to the puerulus larval stage and the final metamorphosis of the spiny lobster, Panulirus japonicus (von Siebold). Zool. Mag., 46(551), 391±9 (in Japanese). Kittaka, J. (1988) Culture of the palinurid Jasus lalandii from egg stage to puerulus. Nippon Suisan Gakkaishi, 54, 87±93. Kittaka, J. & Kimura, K. (1989) Culture of the Japanese spiny lobster Panulirus japonicus from egg to juvenile stage. Nippon Suisan Gakkaishi, 55, 963±70. Kubo, I. (1950) Two types of puerulus larva in Japanese waters, with special reference to the lobster Panulirus versicolor. Bull. Jpn Soc. Sci. Fish., 16, 91±3 (in Japanese). Kubo, I. (1962) Bimodality found in the catches of Japanese spiny lobster, Panulirus japonicus. Bull. Jpn Soc. Sci. Fish., 28, 322±5 (in Japanese). Matsuda, H. & Yamakawa, T. (2000) The complete development and morphological changes of Panulirus longipes (Decapoda, Palinuridae) reared under laboratory conditions. Fish. Sci., 66(2), 278±93. Matsuda, H., Niahimura, A. & Nishimura, M. (1992) A catch record of puerulus by bottom trawl net. Saibaigiken, 20(2), 117±18 (in Japanese). Murano, M. (1971) Five forms of palinurid phyllosoma from Japanese waters. Publ. Seto Mar. Biol. Lab., 19(1), 17±25. Nakamura, K. (1974) Location, occurrence season and body length of palinurid phyllosoma collected off shore of Tokushima Prefecture. Saibaigiken, 3(1), 105±12 (in Japanese). Nakamura, K. (1975) Morphotypes of palinurid phyllosoma collected off shore of Tokushima Prefecture, Saibaigiken, 4(2), 1±8 (in Japanese). Nakamura, S. (1940) Ecological studies of the spiny lobster, Panulirus japonicus (v. Siebold), with special reference to its conservation ± I. J. Imp. Fish. Inst., 34(1), 101±13. Nakazawa, K. (1917) Studies related to the metamorphosis of Panulirus japonicus, with special reference to the larval behavior. Zool. Mag., 29(347), 259±67 (in Japanese). Nonaka, M. (1966) Experiments related to the habitat selection of the Japanese spiny lobster. Bull. Jpn Soc. Sci. Fish., 32, 630±8 (in Japanese). Nonaka, M. (1968) The effect of artificial reefs on the catch of spiny lobster in the coast of Shirahama, Izu Peninsula. Bull. Shizuoka Pref. Fish. Exp. Stn, 1, 43±51 (in Japanese). Nonaka, M. (1982) Characteristics of local stocks of the Japanese spiny lobster. Bull. Shizuoka Pref. Fish. Exp. Stn, 16, 31±42 (in Japanese). Nonaka, M. (1988) Catches of spiny lobster in Japan. Suisan Zoshoku, 36(3), 213±20 (in Japanese). Nonaka, M. & Kageyama, Y. (1981) Summary of reviews presented at the symposium of resource enhancement projects for spiny lobster held in Minami Izu. Fish. Eng., 17(2), 33±5 (in Japanese). Nonaka, M., Fushimi, H., Kageyama, Y. & Sasaki, T. (1980) Occurrence of Palinurid puerulus larva in Japanese waters. Bull. Shizuoka Pref. Fish. Exp. Stn, 14, 43±52 (in Japanese). Nonaka, M., Hatoya, M., Aoyama, M. & Yamamoto, K. (1989) The relative growth of Panulirus phllosoma larvae in Japanese waters. Nippon Suisan Gakkaishi, 55, 605±12 (in Japanese). Nonaka, M., Oshima, Y. & Hirano, R. (1958) Ecdysis and rearing of phyllosoma of Panulirus japonicus. Suisan Zoshoku, 5(3), 13±15 (in Japanese). Norman, C.P., Yamakawa, H. & Yoshimura, T. (1994) Habitat selection, growth rate and density of juvenile Panulirus japonicus (Von Siebold, 1824) (Decapoda, Palinuridae) at Banda, Chiba Prefecture, Japan. Crustaceana, 66, 366±83. Okada, Y. & Kubo, I. (1948) Studies related to the Japanese spiny lobster ± V: puerulus and juvenile stages. Short Rep. Inst. Nat. Res., 12, 20±4 (in Japanese). Okada, Y. & Kubo, I. (1950) Studies related to the Japanese spiny lobster ± VI: morphological comparison of puerulus, juvenile and adult. Short Rep. Inst. Nat. Res., 15, 41±6 (in Japanese). Oshima, Y. (1935) Study of the habitat of the Japanese spiny lobster. Yoshoku Kaishi., 5(5,6), 75±83 (in Japanese).

The Spiny Lobster Fishery in Japan and Restocking

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Oshima, Y. (1936) Feeding habit of Panulirus phyllosoma in early stage. Suisan Gakkaiho, 7(1), 16± 21 (in Japanese). Oshima, Y. (1942a) The phyllosoma genus Panulirus. Suisan Gakkaiho, 9(1), 36±44 (in Japanese). Oshima, Y. (1942b) Ecological observations of the Japanese spiny lobster. Suisan Gakkaiho, 8(3±4), 231±8 (in Japanese). Oshima, Y. (1948) Duration of metamorphosis and age estimation in the spiny lobster, Panulirus japonicus v. Siebold. Bull. Jpn Soc. Sci. Fish., 13, 210±12 (in Japanese). Oshima, Y. (Ed.) (1962) Resource Propagation in Coastal Waters ± Effects on Fishing Yields. Kaibun-Do, Tokyo, Japan, 133 pp. (in Japanese). Oshima, Y. (1976) A technique of resource propagation for the Japanese spiny lobster. Fish. Eng., 12(2), 1±3 (in Japanese). Phillips, B.F. (1972) A quantitative collector of the western rock lobster Panulirus longipes cygnus George (Decapoda: Palinuridae). Crustaceana, 22, 147±54. Saisho, T. (1962) Notes of the early development of phyllosoma of Panulirus japonicus. Mem. Fac. Fish. Kagoshima Univ., 11(1), 18±23. Sekiguchi, H. (1985a) Larval recruitment process of the Japanese spiny lobster Panulirus japonicus (Decapoda, Palinuridae): a fisheries perspective. Benthos Res., 28, 24±35 (in Japanese). Sekiguchi, H. (1985b) Life cycle of scyllarid and palinurid lobster (1). Aquabiology, 8(1), 13±18 (in Japanese). (See also the continuation of this series by H. Sekiguchi in following issues of Aquabiology.) Sekine, S., Shima, Y., Fushimi, H. & Nonaka, M. (2000) Larval period and molting in the Japanese spiny lobster Panulirus japonicus under laboratory conditions. Fish. Sci., 66(1), 19±24. Shizuoka Prefectural Fisheries Experiment Station (1934) An experiment on artificial shelter for spiny lobster. Ann. Rept. Shizuoka Pref. Fish. Exp. Stn, 1933, 151±2 (in Japanese). Suguri, A., Shibahara, N., Mitani, A., & Onishi, N. (1966) On artificial concrete bed for propagation of spiny lobster and abalone. Ann. Rep. Mie Pref. Fish. Exp. Stn, 1964, 200±6 (in Japanese). Takahashi, M. & Saisho, T. (1978) Complete larval development of Scyllarid lobsters, Ibacus ciliatus (von Siebold) and Ibacus novemdentatus Gibbes, under laboratory conditions. Mem. Fac. Fish. Kagoshima Univ., 27(1), 305±53 (in Japanese). Takayama, K. (1939) A tagging technique for the spiny lobster. Suisan Kenkyushi, 34(4), 1±2 (in Japanese). Tanaka, J., Inoue, M. & Nonaka, M. (1988) Guide for Planning Enhancement of Coastal Fisheries Resources: Sea Bream and Spiny Lobster. National Coastal Fishery Development Association (NCFDA), Tokyo, Japan, 362 pp. (in Japanese). Tanaka, T. (1987) Identification of three morphotypes of puerulus larvae (Palinuridae). Bull. Chiba. Pref. Fish. Exp. Stn, 45, 17±22 (in Japanese). Tanaka, T., Ishida, O. & Kaneko, S. (1984) Puerulus larvae of spiny lobsters (Palinuridae) collected from the coast of Chiba prefecture. Suisan Zoshoku, 32(2), 92±101 (in Japanese). Tsuiki, H., Yamakawa, T., Aoki, I. & Taniuchi, T. (1999) Fisheries management of juveniles of the Japanese spiny lobster. Nippon Suisan Gakkaishi, 65, 464±72 (in Japanese). Yamakawa, H. & Nonaka, M. (1988) Characteristics of conserved populations of Japanese spiny lobster Panulirus japonicus (von Siebold). Suisan Zoshoku, 36(2), 113±19 (in Japanese). Yamakawa, T. (1997a) Growth, age composition, and recruitment of the Japanese spiny lobster Panulirus japonicus estimated from multiple length frequency analysis. Bull. Jpn Soc. Fish. Oceanogr., 61(1), 23±32 (in Japanese). Yamakawa, T. (1997b) Stock assessment and fisheries management of the Japanese spiny lobster Panulirus japonicus. Bull. Fish. Res. Inst. Mie, 7, 1±96 (in Japanese). Yamakawa, T. & Matsumiya, Y. (1997) Simultaneous analysis of multiple length frequency data sets when the growth rates fluctuate between years. Fisheries Sci., 63, 708±14.

242 Spiny Lobsters: Fisheries and Culture Yamakawa, T., Matsumiya, Y. & Kitada, S. (1994a) Comparison of statistical models for expanded DeLury's method. Fisheries Sci., 60, 405±9. Yamakawa, T., Matsumiya, Y., Nishimura, M. & Ohnishi, S. (1994b) Expanded DeLury's method with variable catchability and its application to catch-effort data from spiny lobster gillnet fishery. Fisheries Sci., 60, 59±63. Yamakawa, T., Nishimura, M., Matsuda, H., Tsujigado, A. & Kamiya, N. (1989) Complete larval rearing of the Japanese spiny lobster Panulirus japonicus. Nippon Suisan Gakkaishi, 55, 745. Yokoya, Y. (1919) Palinurid phyllosoma. Suisan Gakkaiho, 3(2), 114±15 (in Japanese). Yoshimura, T. & Yamakawa, H. (1988) Microhabitat and behavior of settled pueruli and juveniles of the Japanese spiny lobster Panulirus japonicus at Kominato, Japan. J. Crust. Biol., 8(4), 524±31. Yoshimura, T., Yamakawa, H. & Norman, C.P. (1994) Comparison of hole and seaweed habitats of post-settled pueruli and early benthic juvenile lobsters, Panulirus japonicus (von Siebold, 1824). Crustaceana, 66, 356±65. Yoshimura, T., Yamakawa, H. & Kozasa, E. (1999) Distribution of final stage phyllosoma larvae and free-swimming pueruli of Panulirus japonicus around the Kuroshio Current off southern Kyushu, Japan. Mar. Biol., 133, 293±306.

Part 2 Research for Management: Case Studies

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 14

Reproductive Biology: Issues for Management c . F. CHUBB

Bernard Bowen Fisheries Research Institute, Western Australian Marine

Research Laboratories, P.O. Box 20, North Beach, Western Australia 6020, Australia

14.1

Introduction

The essence of fisheries management is to allow exploitation of the stock for economic and social benefit whilst maintaining its reproductive capacity at a level that provides adequate recruitment to the fishery each year. Combinations of conventional management approaches, i.e. input (fishing effort) controls, output (catch) controls and other regulatory measures such as size limits and seasonal and/ or area closures (Jamieson & Caddy, 1986), have led to different management regimes operating in different spiny lobster fisheries around the world. For example, limited entry fisheries exist in Western Australia and Cuba. In New Zealand and South Africa quota systems of management are applied. The Florida fishery is open access and in countries like Mexico, management is still evolving as the various spiny lobster fisheries develop. The value of spiny lobsters on world markets is high and, in general, stocks are heavily exploited. Thus, sound management decisions are required, their formulation relying upon a detailed knowledge of both the fishery (fishers, fishing techniques and patterns) and the biology of the animal. This knowledge is of particular importance with respect to the level of exploitation and its impact on spiny lobster breeding stocks and, hence, egg production. How high can exploitation be allowed to rise, or to what level can the breeding stock be reduced before recruitment overfishing is experienced? In spiny lobster fisheries, aggregations of lobsters providing the highest catch rates are sought continually, generally with increasing levels of fishing effort. The maintenance of good catches, therefore, may mask signs of recruit overfishing even if independent estimates of recruitment (e.g. puerulus settlement) are available. Wide fluctuations in recruitment due to varying environmental conditions (e.g. Pearce & Phillips, 1988; Phillips et al., 1991; Caputi & Brown, 1993) may hide a seriously declining trend in recruitment for a number of years. Thus, fisheries research on spiny lobster reproductive biology should have the ultimate goal of attempting to understand the fundamental relationship between parent stock and recruitment. This chapter reviews the information sought by fisheries biologists involved in reproductive biological research on the palinurid genera Punulirus and Jusus. Each section deals with a specific aspect of research and provides examples to explain the 245

246 Spiny Lobsters: Fisheries and Culture management implications of these data. Finally, the chapter examines how research advice of this type has been used in the current management of one of the world’s major spiny lobster fisheries, the western rock lobster fishery. Relatively few authors have reported aspects of reproduction in male spiny lobsters, so this chapter concentrates on female spiny lobsters, because research for management is concerned primarily with the effects of fishing on levels of egg production.

14.2 14.2.1

Reproductive biological research and management implications Determination of sexual maturity

An accurate definition of the sexually mature component of the population is required for the management of any stock. Maturity in male spiny lobsters may be defined as either physiological, where individuals produce spermatozoa but are incapable of copulation, or functional, i.e. having the capability to be actively involved in breeding (Aiken & Waddy, 1980). It is not possible to determine physiological maturity in male spiny lobsters simply from an examination of external characters (Lindberg, 1955; Fielder, 1964; Heydorn, 1965; Berry, 1971; Chittleborough, 1974; MacFarlane & Moore, 1986). Neither is it possible from the macroscopic appearance of the testes and vasa deferentia, at least for Jasus lalandii, J . novaehollandiae (= J . edwardsii , see Booth et al., 1990) and Panulirus ornatus (Fielder, 1964; Heydorn, 1965; MacFarlane & Moore, 1986). Chubb (1994) suggested that counts of spermatazoa in the seminal fluid from the vasa deferentia, as reported for P. homarus (Heydorn, 1969a; Berry, 1971), J . lalandii (Heydorn, 1965, 1969b) and J . edwardsii (MacDiarmid, 1989a), appeared to be the only valid method of determining physiological maturity in individual male spiny lobsters. However, Minagawa & Higuchi (1997) contend that physiological maturity (their gonadal maturation) should be determined by an examination of the testis for the presence of sperm. They reason that since a time lag may occur between gonadal maturity and the ability to copulate sucessfully, the presence of sperm and spermatophoric matrix in the vas deferens indicates functional maturity. Minagawa & Higuchi (1997) used the gonadosomatic index (GSI), the ratio of the lumen of the seminiferous tubule to that of the whole tubule (RAL) and sperm density to validate estimates of size of male functional maturity in Panulirus japonicus from morphometric data. Functional maturity in male spiny lobsters has been examined using the linear growth stage-intersect method of George & Morgan (1979) or variants of it. The method indicates the size at which measurable morphological differences (e.g. leg 1ength:carapace length ratio) begin to develop following the attainment of maturity. This technique has provided useful estimates of functional maturity in male P . versicolor (George & Morgan, 1979), P. penicillatus (Juinio, 1987; Plaut, 1993), P.

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longipes longipes (Gomez et al., 1994), P . argus and P. guttatus (Evans et al., 1995; Sharp et al., 1997) and P . japonicus (Minagawa & Higuchi, 1997). Female spiny lobsters are considered mature when they are capable of extruding eggs, with maturity readily determined from external secondary sexual characteristics (Aiken & Waddy, 1980) and the macroscopic and microscopic examination of ovaries. The commonly used terms size at maturity (SAM) and size at onset of breeding refer to functional maturity. The presence of well-developed pleopodal (ovigerous) setae has been regarded widely as indicating the attainment of functional maturity in females of many species of spiny lobster (Nakamura, 1940; George, 1958; Kensler, 1967; Street, 1969; Newman & Pollock, 1971; Beyers, 1979; Roscoe, 1979; Annala et al., 1980; Gregory & Labisky, 1981; Booth, 1984a; MacDiarmid, 1989a; Montgomery, 1989, 1992; Pollock, 1991a; Cockcroft & Goosen, 1995). For Jasus species, except for J. verreauxi (Booth, 1984a), this criterion appears particularly useful, with most females becoming setose at a ‘maturity’ moult and retaining welldeveloped setae at subsequent moults (Fielder, 1964; Newman & Pollock, 1974; Roscoe, 1979; Annala et al., 1980; Pollock, 1986, 1991a, b). However, MacDiarmid (1989b) noted that a proportion of mature female J. edwardsii inhabiting warmer waters loses the ovigerous setae during a second annual moult in summer. Similarly, Hobday & Ryan (1997) cautioned that the use of setae alone could lead to underestimates of egg production and a larger size at maturity because smaller female J . edwardsii are more likely to moult in late spring or summer in Victoria. Grobler & Noli-Peard (1997) in recent work on J. lalandii in Namibia have used the presence of setae or eggs to determine SAM. Some cooler water species of the genus Panulirus moult into a non-setose condition following breeding (Aiken & Waddy, 1980; Chubb, unpubl.), thus requiring at least one further moult prior to mating and the start of oviposition. Care must be exercised in using the presence of ovigerous setae for the estimation of the size at maturity because, at least for some species of Panulirus and J. verreauxi, the precocious development of filamentous setae in smaller females occurs (Chittleborough, 1974, 1976; Gregory & Labisky, 1981; Booth, 1984a; Montgomery, 1989; Fig. 14.1). Thus, unless the relationship between ovarian development and the presence of ovigerous setae has been investigated (e.g. Fielder, 1964; Juinio, 1987), or it can be demonstrated that very few setose females do not bear eggs (e.g. Annala et al., 1980), SAM is likely to be underestimated if based solely on the presence of ovigerous setae. Lyons et al. (1981) cautioned that estimates of size at maturity should be based only on the presence of berried (egg-bearing) females. This practice has been followed by a number of other researchers (Heydorn, 1965, 1969a, b; Berry, 1971; Chitty, 1973; Davis, 1975; Ebert & Ford, 1986; Polovina, 1989; Gomez et al., 1994; Briones-Fourzin, 1995; Sharp et al., 1997). Heydorn (1965) correctly reasoned that a female spiny lobster is sexually mature if she can produce viable eggs. However, this implies that Panulirus females with ovigerous setae and either an unused spermatophore, or remnants of a spermatophore, also are sexually mature because the former condition is pre-oviposition and the latter, post-hatching. Confirmation

248 Spiny Lobsters: Fisheries and Culture a

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Fig. 14.1 Estimates of size at maturity for (a) Punulirus cygnus, indicated by the presence of ovigerous setae on the pleopods (O),spermatophores (x) and eggs (El) at the Abrolhos Islands, Western Australia during the early part (Oct) and peak period (Dec) of the 1984/85 breeding season (lines were drawn by eye); and (b) Jusus verreauxi from the presence of pleopodal setae (0)and eggs (x). After Booth (1984a).

of this inference is possible from ovary staging if the animals are sacrificed (Fielder, 1964; Bell et al., 1987; Juinio, 1987). In some species the larger females in a population may commence mating and egglaying first (Berry, 1971; Lipcius, 1985; Lipcius & Herrnkind, 1987; Chubb, 1991; Briones-Fourzan & Lozano-Alvarez, 1992). Thus, estimates of size at maturity may vary with time, depending upon whether the indicator is the presence of setae, spermatophores or eggs (Fig. 14.la). The size of the smallest berried female found in samples is sometimes quoted as the SAM. Although of biological interest, it 'does little more than note the smallest size at which a small proportion of females become mature. This knowledge by itself is of little use in the formulation of management regulations' (Fielder, 1964, p. 140). The approach of estimating size at maturity from the incidence of mated but non-berried,

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and berried females, adopted by a majority of authors working with Panulirus species (Chittleborough, 1974, 1976; Peacock, 1974; Kanciruk & Herrnkind, 1976; Aiken, 1977; Warner et al., 1977; Gregory et al., 1982; MacDonald, 1982; Juinio, 1987; Lipcius & Herrnkind, 1987; Jayakody, 1989; Cavalcante Soares, 1990; Chubb, 1991; Briones-Fourzan & Lozano-Alvarez, 1992; Evans et al., 1995; Mohan, 1997), is the most appropriate for the purposes of providing management advice. Thus, the SAM ( = size at onset of breeding) for Panulirus should be taken as the size at which 50% of females have ovigerous setae and are mated (unused or eroded spermatophore) combined with those that are berried. For Jusus (except for J . verreauxz] the size at 50% maturity should be estimated from females possessing well-developed pleopodal setae together with those that are berried (e.g. Hobday & Ryan, 1997). For J. verreauxi the SAM is best estimated by the size at which 50% of females are berried (Booth, 1984a; Fig. 14.lb). If the ability to sample adequately over a significant part of the breeding season is curtailed for any reason (e.g. lack of funding), the relationship between the relative growth of body parts may be used to estimate the size at the onset of functional maturity for female spiny lobsters at any time of year. This has been demonstrated by Evans et ul. (1995) using the second walking legs; however, their results indicate a degree of variability compared with SAM estimates using secondary sexual characteristics. More accurate estimates are likely to be gained from intersect analyses using appendages that are intimately associated with the reproductive process such as the fifth pereiopod (George & Morgan, 1979) or the pleopods (Minagawa & Higuchi, 1997). It is important to understand that non-representative sampling may lead to biased estimates of SAM. For example, the estimate of first physical maturity of 69 mm carapace length (CL) for small numbers of trap caught male P . gultatus (Evans et al., 1995) differs from the estimate of 48 mm CL from SCUBA (self-contained underwater breathing apparatus) samples of the same species in Florida (Sharp et al., 1997). The data presented by the former authors lack lobsters smaller than 50 mm CL and the scatterplot does not show any obvious inflexion point. This led Sharp et al. (1997) to conclude that Evans et al. (1995) had sampled exclusively mature individuals, causing them to overestimate the size at functional maturity for this species in Bermuda. Beyers & Goosen (1987) reported two sizes at maturity for female J. lulandii from samples from the Port Nolloth area. Diver samples from deeper water mostly consisted of immature females, while hoop-net samples from shallow water were almost entirely mature females. The SAM calculated from the former sample was almost 10 mm larger than the true value. The selectivity of sampling methods should be understood together with the relative catchabilities of the lobsters (e.g. Kanciruk & Herrnkind, 1976). In addition, researchers should be aware of any offshore-onshore movement of breeding females (e.g. Booth, 1997) when determining the location of samples from which estimates of SAM are to be derived. It is important for managers to be made aware of any differences between

250 Spiny Lobsters: Fisheries and Culture research advice and conclusions drawn by experienced fishers based on traditional capture methods biased by selectivity, time of fishing or catchability problems.

14.2.2

Geographical variations in size at maturity

Geographical differences in SAM are evident in a number of species. Lyons et al. (1981) and Lyons (1986) demonstrated considerable variation in SAM for P. argus throughout the Caribbean region. Similar variations were noted for J. lalandii on the west coast of South Africa and Namibia (Pollock, 1986; Beyers & Goosen, 1987), for P. penicillatus throughout the Pacific (Juinio, 1987) and for J. edwardsii throughout New Zealand and southern Australia (Annala et al., 1980; Hobday & Ryan, 1997). SAM variations for J. tristani were evident between islands at the Tristan da Cunha group (Pollock, 1991a) and similarly for J. paulensis at the islands of St Paul and New Amsterdam (Grua, 1963). Large differences exist between the ‘ coastal’ and offshore Abrolhos Islands populations of P. cygnus in Western Australia (Chittleborough, 1976; Chubb, 1991), with smaller variations (
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Ryan, 1997), may be density-dependence driven. The region of smallest SAM is the centre of J . edwardsii’s distribution, which yields over 60% of the catch (Phillips et af.,Chapter 1). A SAM of 41 mm CL in southern Tasmania (Hobday & Ryan, 1997) reflects the very slow growth of J. edwardsii in this region (Punt et al., 1997). Variations in SAM may have management implications for the application of size limits. For example, the system of total allowable catches for J . falandii in South Africa’s west coast management zones allowed the experimental introduction of a smaller size limit of 75 mm carapace length (CL) in the northern areas (cf. 93 mm CL). In these areas, Cape rock lobsters have a much slower growth rate and a smaller SAM (59 mm CL cf. 66 mm CL) than in other sectors of the fishery (Pollock, 1986).

14.2.3

Effects of fishing and environment on size at maturity

The effect of fishing upon SAM, in general, has not been addressed in the literature, usually because of the inadequacy of data from a fishery’s early developmental period. However, data are available for some fisheries and the issue has been considered in a theoretical context by Pollock (1993, 1995a, b). He hypothesized that compensatory growth caused by a fishing-induced reduction in density would lead to a larger size at maturity. Under sustainable exploitation, fishing mortality is just another component of total mortality which, when varied, would lead to densitydependent changes in growth and SAM. Under extreme fishing pressure (i.e. overexploitation), populations appear to exhibit decreased SAM, perhaps as a result of rapid harvesting of faster growing lobsters. George (1958) noted a SAM for P . cygnus of 75-80 mm CL when densities were much higher, compared to the 90-95 mm CL recorded for the Western Australian ‘coastal’ stock in recent times. This prompted Chittleborough (1979) to hypothesize an increased SAM resulting from higher (density-dependent) growth rates as fishing reduced the abundance of the adult population. Later, Pollock (1987, 1991b, 1993) further hypothesized that, for a time, similar levels of egg production (population fecundity) would have been maintained by more fecund, but fewer, larger-sized females. However, a logical ceiling to these density-dependent compensatory mechanisms would exist and with continuing high rates of exploitation, population fecundity must decline. Investigation of this issue for P . cygnus revealed that George’s (1958) SAM was estimated from samples caught in a single inshore location and was not representative of the coastal breeding stock as a whole (R.W. George, Western Australian Museum, Perth, WA, Australia, pers. comm.), thus invalidating comparisons with more recent data. Furthermore, data collected from monitoring spiny lobster catches on-board commercial fishing vessels show a shift in the SAM of female P . cygnus in the southern sector of the coastal breeding stock from 97 to 93 mm CL between the 1970s and the early 1990s (Western Australian Fisheries Department, unpubl.). This decline occurred concomitantly with increasing effective

252 Spiny Lobsters: Fisheries and Culture fishing effort. In the Hawaiian Islands, Polovina (1989) recorded a significant decrease in the size of berried P. marginatus as the exploitation rate increased markedly over a 10-year period. DeMartini et al. (1992) have suggested that the greater decline in SAM at Necker Island than at Mar0 Reef, even though preexploitation densities were greater at Necker Island, was possibly due to the higher rate of depletion there. Both the Hawaiian and Western Australian experiences provide evidence that fishery-induced reductions in female SAM may occur in heavily exploited (overexploited) spiny lobster stocks. The influence of environmental factors on SAM has recently been documented by Cockcroft & Goosen (1995). They reported how negative growth (shrinkage) in J . lalandii populations significantly reduced SAM in the four locations studied. The widespread nature of this reduction in lobster growth rates indicated a large-scale environmental perturbation associated with the El Niiio years of 1990-1993 (Pollock et al., 1997). The view that the variation in size structure and SAM for P. homarus in regions of Oman resulted from differences in environmental conditions was subscribed to by Mohan (1997). Both Warner et aE. (1977) and Lyons et al. (1981) reported significant numbers of sublegal size berried P. argus in the heavily fished Florida Keys population, whereas in the virtually unfished population at Dry Tortugas, no breeding females were below the legal minimum size (Davis, 1975). While this may simply reflect variations in environmental effects on growth rates, since densities are likely to be greater at Dry Tortugas, and it may be further evidence of changes in SAM induced by very high fishing mortality. One interesting point here is that for P. cygnus and P. marginatus stocks, recruitment is sourced from endemic breeding populations, whereas, for P. argus and others (e.g. P. versicolor), pueruli are sourced from much wider geographical distributions, e.g. pan-Caribbean. The biological implications of recruitment dynamics and their effect on SAM are beyond the scope of this review. It is enough for managers to know the exploitation rate, how SAM has varied historically (if possible) and its relationship to legal size limits.

14.2.4

Size at maturity and size limits

Historically, size limits appear to have been set at the acceptable market size, with protection of the reproductive capacity of the stock a secondary consideration. They were often set during the infancy of a fishery when the stock was subject to low levels of fishing. If the legal size limit is set below the SAM, minimal protection of maturing and mature spiny lobsters is afforded. Increasing rates of exploitation lead to considerably reduced levels of egg production and, unless controlled, ultimately to recruit overfishing. An example is in the P. cygnus fishery, where the legal minimum size of 76 mm CL is well below the size at 50% maturity (90-95 mm CL) for a major portion of the stock. Thus, considerable fishing pressure is exerted on female western rock lobsters for 1-2 years prior to their becoming sexually mature. Maintenance of

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very high exploitation rates reduced population egg production to levels not previously experienced in the fishery. To halt the decline, the simple answer would have been to invoke a substantially larger minimum legal size. However, in an intensive, established fishery, with well-developed, lucrative markets based around the minimum size, it may be easier to institute significant reductions in fishing effort than to attempt to implement higher minimum size limits and disrupt the markets. Nevertheless, there may be some benefit in raising the minimum size in some cases. For example, Hunt & Lyons (1986) have suggested that an increase from 76 to 85 mm CL would allow P . argus in the Florida Keys to breed at least once and would increase yield to 95% of maximum yield-per-recruit. Alternatively, size limits may be set too high, relative to SAM, and protection may be too great, resulting in an unnecessary enforced reduction of catch and loss of income for fishers and government. In the P . gracilis and P . inflatus fishery on the Mexican west coast, the minimum size regulation introduced was simply that which applied to P . interruptus in Baja California. Briones-Fourzan & Lozano- Alvarez (1992) have reported that fishers believed the minimum size limit was too high, and thus they did not observe it at all. Briones-Fourzan & Lozano-Alvarez (1992) recommended a considerably reduced size limit, but still above the SAM. In developing fisheries, alterations to size limits are accommodated more readily. A rational recommendation based on sound research and consistent with industry’s views stands a good chance of success in meeting industry’s requirements, being enforceable and, therefore, conserving egg production. A similar situation occurs in Oman, where lack of enforcement has made management regulations, including an 80 mm CL minimum size, ineffective (Mohan, 1997). Mohan further reported that owing to the geographical variation in SAM, the size limit may not apply equally in all areas, and variable minimum sizes might be an option for managers, but in practical terms would prove difficult to enforce. Size limits in some fisheries are set above the SAM, resulting in the protection of practically all mature females. In these cases, egg production is more than sufficient to ensure adequate recruitment. Examples are the South African fishery for J. lalandii (Pollock, 1986) and (parts of) the Tasmanian fishery for J . novaehollandiae ( = J . edwardsii) in which Harrison (1988a, b) noted, that under the established limited entry regime, the stringently enforced minimum size limit obviated any need for further controls on fishing effort. The Tasmanian fishery now is controlled by quotas; the creep in effective effort in input-controlled fisheries should never be underestimated. Tools that assist in determining appropriate size limits include yield-per-recruit (YPR) and egg-per-recruit (EPR) analyses. For example, J. edwardsii in the Otago region have a SAM of 12&124 mm CL, which is amongst the largest in New Zealand (Annala, 1991). At the same time, Otago has a smaller legal minimum size for capture than the rest of New Zealand (equivalent of 79 mm cf. 93 mm CL for females), established without scientific basis in the 1950s (Annala, 1977). The raising of the size limit for females at Otago to 93 mm would result in an increase in YPR of

254 Spiny Lobsters: Fisheries and Culture 15-20% and a fivefold (but still small) increase in egg production (Annala & Breen, 1989). Theoretical treatment of the application of EPR analyses and size limits in relation to the resilience of lobster populations has been given by Pollock (1993). A management technique introduced into the P . cygnus fishery in the 1992/93 season is the implementation of a maximum size limit of 115 mm CL for females. This was followed in 1993/94 by a split maximum size limit of 105 and 115 mm CL to cater for differences in size distributions throughout the management zones. Because of their maturity, size and longevity, these larger, often less valuable lobsters were expected to exert a stabilizing influence on the downward trend in egg production and assist in reducing the dependency of the breeding stock upon one or two age classes. Consideration should be given to the impact of a maximum size limit upon total catch and the catch of individual fishers. In particular, any redirection of fishing effort towards smaller lobsters, which may reduce recruitment to the breeding stock, should be assessed and appropriate regulatory measures taken if necessary. Sources of recruitment are an interesting issue in the consideration of stock sustainability. Where parent stock and recruitment are managed by a single jurisdiction, e.g. the western rock lobster fishery, the 'health' of the breeding stock is vital to sustain recruitment and YPR and EPR analyses will assist in setting an appropriate legal minimum size. In fisheries where pueruli are sourced from breeding populations covering spatially huge distributions, e.g. P. argus fisheries in Florida and the Caribbean, the J . edwardsii fisheries in southern Australia and many species with Indo-Pacific distributions, the relative importance of the various breeding populations is unknown. Where it can be assumed that recruitment of a particular species will be sustained, the issue of minimum size becomes one of local depletion and maximizing YPR. However, in regions where fisheries are well developed and exploitation rates high, Hobday & Ryan (1997) rightly caution that until recruitment processes are defined, the various sectors of the fishery should aim to maintain suitable levels of egg production. With this in mind, (Hobday & Ryan, 1997) are suggesting a review of size limits for J. edwardsii in Victoria based on the geographical variation in SAM documented by them.

14.2.5

Breeding periods and seasonal closures

Breeding periods may be defined by temporal development of the ovaries (e.g. Gomez et al., 1994; Minagawa, 1997) and/or the seasonal or monthly presence of berried females and, for Panulirus, the presence and state of spermatophores. With one exception, all species of Jams inhabit cold waters between latitudes 35 and 45"s and have similar breeding cycles, with oviposition occurring during late autumn or winter and egg incubation taking 4-6 months, depending on water temperature (Pollock, 199 1b). Jasus verreauxi, however, is found further north along the Australian east coast to about 30"s latitude and breeds in the spring and summer (Booth, I984a). Temperate and subtropical species of Panulirus generally have a

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well-defined breeding season in spring-summer or summer-autumn, with eggs hatching within 1-2 months of oviposition (Nakamura, 1940; Wilson, 1948; Ino, 1950; Heydorn, 1969a; Mitchell et a[., 1969; Berry, 1971; Caillouet et al., 1971; Chitty, 1973; Nascimento, 1973b; Rongmuangsart & Luvira, 1973; Chittleborough, 1976; Marfin, 1978; Lyons et al., 1981; MacFarlane & Moore, 1986; Vega, 1991; Plaut, 1993; Minagawa, 1997). Panulirus species or populations with more tropical distributions may breed year round with pauses in reproductive activity for moulting (Creaser, 1950; Nascimento, 1973b; Aiken, 1977; Briones-Fourzan et al., 1981; MacDonald, 1982; Ebert & Ford, 1986; Juinio, 1987; Briones-Fourzan & LozanoAlvarez, 1992; Gomez et al., 1994; Sharp et al., 1997). Breeding seasons are under the influence of a suite of environmental conditions, e.g. temperature and photoperiod (Chittleborough, 1976; Lipcius, 1985; Lipcius & Herrnkind, 1987; Deguchi et al., 199l), and annual variations in these conditions will result in breeding commencing earlier or later by as much as 1 month in P. argus, P . cygnus, P . guttatus, P . interruptus, P . japonicus and J. lalandii (Nakamura, 1940; Sutcliffe, 1953; Chitty, 1973; Newman & Pollock, 1974; Vega, 1991; Chubb, unpubl.). Geographical variations in breeding period have been recorded for P. longipes longipes with continuous breeding in the Philippines but distinct seasonal breeding in Okinawa (Gomez et al, 1994). Similarly, P. guttatus breeds year round in Florida and Martinique, but in Bermuda berried females are absent during winter and spring, reflecting the cooler water temperatures and shorter photoperiod (Sharp et al., 1997). Seasonal closures, usually around the time of breeding, are another well-utilized regulatory measure in spiny lobster fisheries. In addition to reducing exploitation, closures prevent disturbance of the breeding population at a critical phase in their life cycle. Closures are most appropriate in populations where breeding is distinctly seasonal. Closed seasons of 3-5 months are not unusual in these fisheries (Lyons et al., 1981; Villegas et al., 1982; Lamadrid & Blanco, 1986; Pollock, 1986; Phillips & Brown, 1989; Vega, 1991). Research into variations in breeding periods and the sensible application of closed seasons can help industry to be more profitable, in addition to achieving a measure of protection for the breeding stock. For example, in the P. interruptus fishery on Mexico’s Baja California west coast, Vega (1991) described a request by the fishing co-operatives in the central and northern zones of the fishery for an adjustment to the closed season. Their argument was that considerable numbers of females ‘in an advanced state of reproduction’ were appearing in the catches in the last 2 months of the season. Research showed a distinct latitudinal variation in the commencement of breeding, on which Vega (199 1) based a recommendation for the application of zonal closed seasons allied to the timing of reproduction. Latitudinal variability in reproduction was noted also for P. marginatus, ranging from year-round reproduction in the main Hawaiian Islands to distinct seasonality at Midway Islands and Kure Atoll to the north-west (Anon., 1986). Although lobster fishers suggested a closed season to protect reproduction of spiny lobsters, managers felt that such a measure would provide only limited conservation of the breeding stock,

256 Spiny Lobsters: Fisheries and Culture and would have discriminatory economic impacts on some sectors of the fishery. Management considered that a more equitable and effective conservation measure was to make escape vents mandatory in all traps (Anon., 1986). This would increase survival of juveniles and promote recruitment into the breeding stock.

14.2.6

Brood size and egg production

Fecundity in spiny lobsters is often defined as the number of eggs carried externally on the pleopods of a female. Pollock & Goosen (1991) have used the term brood size, which is appropriate particularly for species that spawn repetitively during a breeding season. Fecundity thus may be considered as the total egg production from a single female, or the combined spawnings by an individual female in a single breeding season or breeding period. Brood size-CL relationships have been investigated routinely for many species of spiny lobster. The choice of method used to estimate brood size for individuals should be made cautiously. In laboratories where electronic egg counters (e.g. Bycroft, 1986) are not available, gravimetric methods are still employed and accurate estimates of brood size are calculated using counts from two or three weighed subsamples and the weight of the whole egg mass from individual females (e.g. Kensler, 1967, 1968; Morgan, 1972; MacFarlane & Moore, 1986; Beyers & Goosen, 1987). Volumetric methods have been used to estimate brood sizes (Marfin, 1978) but these appear to produce highly variable results in the brood sizes of females of comparative size and are considered to be less accurate than gravimetric techniques. In many cases a straight-line fit to the raw data may adequately describe the brood size-CL relationship over the range of data collected (e.g. Berry, 1971; McGinnis, 1972; Morgan, 1972; Chitty, 1973; Nascimento, 1973a; MacFarlane & Moore, 1986; MacDonald, 1988; Mohan, 1997). Honda (1980) reported a linear relationship for P . marginatus but suspected that it was curvilinear, as reported subsequently by De Martini et al. (1992). The linear relationship reported for P . cygnus by Morgan (1972) was revised by Chubb (1991), who showed it to be curvilinear after the addition of brood size information from a wider size range of animals. Geographical variations in the nature of the brood size-CL relationship have been reported for the same species. For example, in P . argus the relationship is linear in one part of its distribution (Nascimento, 1973a) but curvilinear in others (Mota Alves & Bezzera, 1968; Cruz et al., 1987; Cruz & de Leon, 1991). Similarly, MacDonald (1988) showed a linear relationship for P . penicillatus in Palau, but Juinio (1987) and Plaut (1993) demonstrated a curvilinear relationship in the Philippines and the Red Sea, respectively. Chitty (1973) reported a linear relationship for P . guttatus in Florida, whereas in the Mexican Caribbean it is curvilinear (Briones-Fourzan, 1995). These differences often appear to be a function of limited sampling of berried females because, in general, common CL will yield similar numbers of eggs regardless of the relationship. Several studies have

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concluded that brood size-CL relationships do not vary geographically (e.g. Morgan, 1972; Lipcius et al., 1997). However, distinct geographical differences do occur. Annala & Bycroft (1987) and Beyers & Goosen (1987) reported significant variations in brood size-body size relationships at the extremities of the fisheries for J. edwardsii (New Zealand) and J . lalandii (South Africa), respectively. De Martini et al. (1993) documented a 16% (significant) difference in size-specific brood size for P . marginatus at Necker Island compared with Mar0 Reef, which they consider to be a ‘biologically meaningful change’ resulting from heavy exploitation and several poor larval recruitment years. They point out that many studies have been unable to detect geographical variations because sample sizes are too small and statistical power is too low. They advise that future studies should report statistical power, particularly when tests are unable to reject the null hypothesis of no difference among populations. Care should be taken to ensure that berried females are sampled adequately over their entire size range. Failure to do so may well lead to the use of relationships, in the calculation of population fecundity (Section 14.3), which bias the contribution to egg production by some size classes. The question of which model best describes size-specific brood size in spiny lobsters (and other crustaceans) has been addressed by Somers (1991). He preferred the log-log allometric model for three reasons. Firstly, logarithmic transformations produce scale-independent regression slopes; secondly, they stabilize the variance in brood size, and thirdly, they contract interpoint distances among data for the largest females, which tend to be the most variable and influential in estimating regressions. Furthermore, analyses of covariance can be utilized to compare size-specific broodsize regressions from different regions or seasons (Bagenal, 1973), an approach which Somers (1991) laments is not used routinely by crustacean biologists. Significant differences between regressions may be pinpointed a posteriori using the Newman-Keuls test (e.g. Annala & Bycroft, 1987). Spiny lobsters may produce from one to four broods of eggs within the same breeding season or period. All Jams species are restricted to the oviposition of a single brood of eggs per breeding season (Pollock, 1991b). By contrast, P . argus, P. cygnus, P . guttatus, P . longipes longipes, P . penicillatus and P . japonicus breed twice (Creaser, 1950; Ino, 1950; Sutcliffe, 1953; Chitty, 1973; Gregory et al., 1982; Lipcius, 1985; Juinio, 1987; Chubb, 1991; Gomez et al., 1994). For species that breed repetitively, the newly matured females produce fewer broods. So for P. cygnus, P. iongipes longipes and P . guttatus the youngest breeding females spawn only once (Chubb, 1991; Gomez et al., 1994; Sharp et al., 1997). While the smaller females of P. gracilis, P. homarus, P . injlatus and P . ornatus breed twice, the larger females may hatch up to three or four broods during a single reproductive period (Berry, 1971; Briones-Fourzan et al., 1981; MacFarlane & Moore, 1986; Briones-Fourzan & Lozano-Alvarez, 1992). An ‘isolated’ population of P. penicillatus breeds from two to four times per breeding season (Plaut, 1993). Considerable reductions in brood size (occasionally up to 70%) for repeat spawnings within the same season were reported by Creaser (1950), Ino (1950) and

258 Spiny Lobsters: Fisheries and Culture Minagawa & Sano (1997), MacFarlane & Moore (1986) and Briones-Fourzan & Lozano-Alvarez (1992) for P . argus, P . japonicus, P . ornatus and P . inflatus, respectively. No evidence of significant variation in repetitive brood size has been reported for other species (Berry, 1971; Chitty, 1973; Juinio, 1987; Chubb, 1991; Plaut, 1993). Caution should be exercised in determining brood size-body size relationships in species where repetitive brood sizes are significantly reduced. Apparent reproductive senescence has been noted in the very large females of some spiny lobster species. Peacock (1974) and Davis (1975) both showed that reproductive activity declined in large female P . argus, thus implying the presence of large barren females in the populations. Reproductive senescence in the form of reduced brood size of very large J. verreauxi and J . edwardsii was reported by Kensler (1967, 1968). However, Annala (1991) offered another explanation for J . edwardsii, suggesting that an increase in egg size with increasing body size consequently resulted in reduced brood sizes for larger females. Regardless of the reasons, the presence of reproductive senility in very large female spiny lobsters, whether real or perceived, and its contribution to egg production is generally not an issue, because in highly exploited spiny lobster stocks, few of these individuals remain. However, if reproductive senescence occurs, overestimates of the spawning potential of the original unexploited stock may result when using fecundity-CL relationships from heavily fished populations, because this may involve extrapolation of the fecundity of very large females. The issue of reproductive senescence should be considered if maximum size limits are to be imposed on a fishery. Most size-specific brood size investigations have involved newly laid or early stage eggs to avoid problems of egg loss owing to dislodgement, fungal or nematode attack during the incubation period. Studies assessing egg loss (and infertility) in spiny lobsters are apparently restricted to those of Morgan (1972) and MacFarlane & Moore (1986), who reported insignificant levels of egg loss and generally very low levels of infertility for P . cygnus and P . ornatus, respectively, and Annala & Bycroft (1987) who estimated egg loss of 20% for J. edwardsii. Because the incubation period for the first two species is 1-2 months (Chittleborough, 1976; MacFarlane & Moore, 1986) and for the last species 4-6 months (Pollock, 1991b), egg loss is probably a function of the length of time for which the eggs are carried by the female. Both the variability of egg loss with size and its significance should be investigated when establishing brood size-body size relationships. This is important if sizespecific brood size information is to be used in stock and recruitment analyses where egg production from parent stock is quantified and related to puerulus settlement or recruitment to the fishable stock. Provided egg loss is approximately proportional to body size, then absolute brood size may be used to assess the relative reproductive potential of different size classes of breeding female spiny lobsters, and calculate annual indices of population egg production.

Reproductive Biology: Issues for Management 14.3

259

Fecundity, population egg production and stock and recruitment

Fecundity combines the number of broods, brood size, egg loss and senescence into a single value for egg production from various-sized spiny lobsters within a population. Some researchers have used mean fecundity at size to examine the reproductive potential (population fecundity) of breeding stocks. The relative fecundity measure of Berry (1971), index of reproductive potential (IRP) (Kanciruk & Herrnkind, 1976) and the reproductive rates of MacDonald (1988) may be used in a number of ways (Fig. 14.2). Firstly, they may serve to determine the size classes of breeding females contributing most to the egg production from the population (see also MacFarlane & Moore, 1986; Juinio, 1987; Briones-Fourzan & Lozano-Alvarez, 1992; Gomez et af., 1994; Hobday & Ryan, 1997; Mohan, 1997). They have been used to estimate how low P . argus egg production was driven by fishing by comparing IRPs from fished and unfished populations (Lyons et al., 1981). They provide the ability to examine egg production differences between different rock lobster species inhabiting similar areas (MacDonald, 1988). More sophisticated analyses involve the combination of reproductive information with growth and mortality data in EPR models (Annala & Breen, 1989; Annala, 1991) and fecundity-per-recruit models (Pollock, 1991b; Pollock & Goosen, 1991; Fig. 14.2d). These models are very useful for determining the fecundity of a female lobster over its lifetime (Pollock, 1991b), investigating the effects of SAM, fecundity and growth rate on EPR (Annala, 1991), and comparing estimates between fished and unfished EPR (Annala & Breen, 1989). In the absence of stock-recruitment data, the last comparisons allow judgement of whether egg production is sufficient to allow a fished population to be sustained (Annala and Breen 1989). An annual index of egg production has been calculated only for P. cygnus (Morgan, 1980). It was used as an indicator of trends in breeding stock abundance and in an attempt to examine stock and recruitment relationships in this species (Morgan et al., 1982). Subsequent assessments of the estimates of breeding stock abundance and egg production (Phillips & Brown, 1989; Chubb unpubl.) have shown that although the Morgan et al. (1982) breeding stock-recruitment relationship was useful as a first approximation, it is no longer an adequate description and should not be used. Stock-recruitment relationships for P . cygnus have been reassessed (Caputi et al., 1995a; see Section 14.6). Understanding the impact of fishing upon egg production from a spiny lobster population is crucial to maintaining a viable fishery. Increases in fishing efficiency lead to increases in fishing mortality (F), which must be taken into account, particularly when calculating annual population fecundity from catch-rate-based data. Failure to do so will cause a more optimistic conclusion about egg production than is actually the case (Fig. 14.3). EPR analyses, trends in annual indices of population fecundity and stock-recruitment relationships permit consideration of whether egg production is at a level that historically has generated adequate recruitment. The effect of environment on recruitment must not be neglected,

260 Spiny Lobsters: Fisheries and Culture a

3U

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270-

-

E 180-

0 Cn

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Fig. 14.2 Use of indices of reproductive potential (IRP) and relative fecundity. (a) Determination of the contribution of various size classes to population egg production, e.g. ‘coastal’ (TR, DO) and Abrolhos Islands (AI) populations of Panulirus cygnus (relative fecundities are not comparable between regions in this example). (b) Estimation of egg production between regions using standardized IRP, e.g. for Punulirus urgus at Dry Tortugas and the Florida Keys (shaded). After Lyons et ul. (1981). (c) Comparison of size-specific reproduction rates (S-SRR) between different species occurring in the same area, e.g. for Panulirus versicolor and Panulirus penicillatus at Palau, Western Caroline Islands. After MacDonald (1988). (d) Comparison of egg production per 10 mm size class from fecundityper-recruit calculations for Jusus tristuni (J.t.) at Inaccessible (0)and Nightingale ( x ) Islands and Jusus lalundii (J.1.) in South Africa, and Jasus edwardsii (J.e.) from New Zealand. After Pollock (1991b); Pollock & Goosen (1991).

because much of the variation in annual catches from spiny lobster fisheries can be attributed directly to the effects of a fluctuating environment. For example, Pearce & Phillips (1 988) established a correlation between El Niiio Southern Oscillation (ENSO) events, the strength of the Leeuwin Current system and puerulus settlement

Reproductive Biology: Issues for Management

l2 10

26 I

1

8

6 4

Season Fig. 14.3 Preliminary catch rate based spawning stock indices for the western rock lobster (Punulirus cygnus) calculated using nominal fishing effort (0)and standardized fishing effort (0) assuming a 2% increase in fishing efficiency each season.

in the western rock lobster. With little or no understanding of the role of environment, unnecessarily cautious management decisions have to be made. However, spurious correlations between environment and recruitment are misleading and dangerous in the management sense (Walters & Collie, 1988). If egg production has been reduced to low levels and recruitment is threatened, then hard decisions must be taken by the managers to stabilize the fishery and maintain its viability. Fortunately, with the advent of high-powered computers, length and agestructured population modelling has become routine in lobster research (e.g. Walters et al., 1993; Hail & Brown, 1994; Ennis & Fogarty, 1997; Muller et al., 1997; Punt & Kennedy, 1997). These models integrate all biological and fishery knowledge for a species and allow the assessment of the impacts of current management arrangements, or future options, on population egg production and catch, and often include risk analysis. For example, Punt & Kennedy (1997) found that egg production in Tasmanian stocks of J. edwardsii varied from as low as 6% of the unexploited equilibrium level in the north to more than 80% in the south-west. Where sufficient time-series of data, and contrast within the data exist, these models are invaluable tools for researchers providing advice to managers about the sustainability of spiny lobster fisheries. The form of the underlying stock-recruitment relationships, so often masked by compensatory growth and survival and wide

262 Spiny Lobsters: Fisheries and Culture interannual fluctuations in larval settlement (Pollock, 1993), can be assumed in the models and sensitivity of the population parameter estimates to the assumption can be assessed.

14.4

Migrations and recruitment to the breeding stock

Many spiny lobster species have complex local movement patterns and some, e.g. P. argus, P. cygnus, P . ornatus, J. edwardsii and J . verreauxi, undertake directional long-distance migrations (Herrnkind, 1980; Annala, 1983; Booth, 1984b, 1986, 1997; Moore & MacFarlane, 1984; Bell et al., 1986, 1987; Phillips & Brown, 1989; Chubb, unpubl.). These generally contranatant migrations (into the prevailing current) are by pre-mature or spawning lobsters (in the case of P. ornatus) distributing themselves into their breeding areas and thereby ensuring the best chances of larval survival and subsequent settlement of pueruli. Although some migrations may be on a broad front, e.g. P . cygnus and P . argus, others such as P . ornatus and J . verreauxi follow distinct pathways or routes (Moore & MacFarlane, 1984; Booth, 1986, 1997). The increased vulnerability to fishing of lobsters undergoing pre-spawning or spawning migrations is of particular importance to managers because relatively high exploitation rates on these individuals can substantially reduce recruitment to the breeding stock and hence population egg production. As an example, Booth (1986) has pointed out that the single major breeding population and migratory pathway for J. verreauxi in New Zealand may mean that this species is particularly vulnerable to overfishing. Similarly, P. ornatus undertakes an annual migration from juvenile areas in Torres Strait to breeding grounds off Yule Island in Papua New Guinea (Moore & MacFarlane, 1984; Bell et al., 1986, 1987). In the mid-l980s, in response to reduced catches in the artisanal fishery around Yule Island (at the time the only known major breeding area for this species), the Papua New Guinean and Australian governments banned trawling for P. ornatus across its migratory route (Williams, 1986; Nambiar, 1990). Subsequently, no connection was found between trawl catches and abundance at Yule Island (Phillips & Trendall, 1989). However, it was argued that protection of the breeding migration should remain, primarily because most spawning females breed for one season, then die from the combined physiological stress of migrating and breeding (Trendall & Prescott, 1989; Pitcher et al., 1991; Dennis et al., 1992).

14.5

Sanctuary and reserve areas

The establishment of sanctuary areas, provided they are sufficiently large and enforcement is effective, is extremely useful for understanding the impact of fishing on wild spiny lobster stocks. For example, the Dry Tortugas sanctuary in Florida, established since 1935 (Davis, 1975), provides a wonderful and unique opportunity

Reproductive Biology: Issues for Management

263

to examine fishing-induced differences in the size structure, reproductive potential and overall levels of egg production from fished and unfished P . argus spawning populations. Similar opportunities are available at more recently established marine reserves in South Africa (e.g. at Robben Island), in New Zealand near Leigh and at Laysan Island in the Hawaiian Islands, where research has shown that spiny lobster densities are greater and sizes larger within the sanctuary areas (Heydorn, 1969b; Anon., 1985; Cole et al., 1990). In addition to the benefits outlined above, Childress (1997) cited the potential for increased recruitment as well as increased egg production and the numerous ecosystem benefits from reduced disturbance as advantages of the establishment of marine reserves. In this context, Lozano-Alvarez et al. (1993) proposed that deep, currently unfished areas of the Caribbean should be left undisturbed as a means of preserving groups of reproductive P. argus that contribute larvae to the regional pool. Prior to establishing reserves, consideration should be given to the behavioural, ecological and spatial requirements of each life-history stage, appropriate experimental design and analysis to assess the reserve’ s effectiveness, economic and social implications, and the traditional use of resources by indigenous peoples (Childress, 1997). A considerable period is required before the research benefits of sanctuary areas become fully apparent. However, the foresight shown by establishing sanctuaries and reserves, perhaps under an adaptive management regime (Walters, 1986), will always be praised by future spiny lobster fisheries scientists and managers alike, as well as the general public who may well use these areas for recreation (Davis & Dodrill, 1980).

14.6

Case study: The Western Australian western rock lobster (Punulirus

cygnus) The western rock lobster fishery commenced in the 1890s but has operated under a policy of strictly limited entry since 1963 when the numbers of vessels and pots (traps) were frozen. The fishery now supports 596 (1998/99) vessels with 69 300 licensed pots landing an average annual catch of 10 800 t valued (ex-vessel) at around Aus $250 million (see Phillips et al., Chapter 1, and Caputi et al., Chapter 18, for a detailed description of the fishery). In the late 1980s and early 1990s, the western rock lobster fishery experienced considerable increases in effective effort despite a temporary 10% reduction in pot usage in 1986/87 followed by a permanent removal of 10% of licensed pots at 2% per season over the period 1987/88-1991/92. Despite this reduction in pot allocation, nominal fishing effort in this already fully exploited fishery continued to increase. At the same time new technology, in the form of global positioning systems (GPS), newgeneration colour and black-and-white echo sounders and the like, were being assimilated quickly into the fishery. Their effect was immediate and pronounced (Brown et al., 1995). Computer-simulation models showed the level of egg

264 Spiny Lobsters: Fisheries and Culture production to be at 15-20% of the unfished equilibrium level (Hall & Brown, 1994) with the potential for fishers to target deep-water habitat (breeding grounds) very effectively with the use of GPS and colour sounders. This potential was realized rapidly as fishers quickly became proficient in the use of the new technology and generated increases in catch rates of between 13 and 17% in waters deeper than 37 m (Brown et al., 1995). Effective fishing effort continued to rise, with the total catch sustained and population egg production declining to the lowest recorded levels (Caputi et al., 1995b). From the mid-1980s to early 199Os, research aimed at improving the spawning stock index (measure of population fecundity) used in the P. cygnus fishery was undertaken. Important findings were in contrast to previous beliefs. For example, size-dependent repetitive breeding is undertaken by at least two-thirds of the breeding female lobsters, the brood size-CL relationship is curvilinear, first and second broods contain the same number of eggs and a major contribution to egg production is made by the breeding population at the offshore Abrolhos Islands (Fig. 1.7) (Chubb et al., 1989; Chubb, 1991). Regional indices of spawning stock abundance were produced from the extensive fishery databases combined with the latest biological information. Comparisons of the regional indices indicated the importance of the contribution to population egg production of the high-density breeding population at the Abrolhos Islands, which Morgan et al. (1982) estimated to be 14%. Later (Chubb et al., 1989) indicated that it was of the order of 50%, due probably to the rapid fishery-induced declines in egg production by the coastal breeding populations. Spawning stock indices are currently based upon catch rates from the commercial fishery adjusted for increases in fishing efficiency (Fig. 14.3). This adjustment is necessary, particularly in the P . cygnus fishery, where modernization of the fleet and the introduction of the latest technologies occur continually. In 1991 it was decided to instigate a fishery-independent survey of the breeding stock of P. cygnus. This is a systematic survey of the breeding grounds conducted just prior to the start of the rock lobster season and at the beginning of the breeding season. These data have provided a calibration for the indices calculated from the fishery data. At the same time new technology was having an impact on the breeding stock, the puerulus settlement declined in 3 successive years to below-average levels with settlement of the offshore Abrolhos Islands from 1984 onwards, on average, 50% below that recorded from 1971/72 to 1978/79 (Caputi et al., 1995a, b). The existence of long time-series of data enabled stock-recruitment analyses to be undertaken for the coast and Abrolhos Islands populations (Caputi et al., 1995b). Those analyses produced relationships (Fig. 14.4) that are markedly different from and now supersede that described by Morgan (1980). Large fluctuations in coastal puerulus settlement were due to environmental factors, with spawning stock being insignificant after taking environment into account, whereas both spawning stock and environment were significant factors affecting the level of settlement at the Abrolhos (Caputi et al. 1995b). The very high, and increasing, exploitation rates; the

265

Reproductive Biology: Issues for Management

very low estimates of spawning stock abundance; the smaller SAM in some regions of the fishery; the significance of spawning stock as a factor determining the Abrolhos settlement; the fact that egg production was reliant upon one or two age classes, and the declining puerulus settlements, all combined to suggest strongly that (a)

*95(75) *89(78)

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266 Spiny Lobsters: Fisheries and Culture the first stages of recruitment overfishing in the western rock lobster fishery were in evidence. In a sense this was not surprising because the SAM for coastal breeding female lobsters is 90-95 mm CL and the legal minimum size is 76 mm CL, so immature females are fished for 1-2 years before they reach maturity. The offshore Abrolhos Islands, however, harbour high densities of sexually mature sublegal size lobsters which produce about 35% of the total fishery egg production (Chubb et al., 1989; Chubb, 1991). Berried females are protected and the contribution from sublegal size animals at the Abrolhos Islands is significant. Given this, and assuming that recruitment to the Abrolhos Islands will be maintained, in stock and recruitment terms there will always be a base level of egg production in the western rock lobster fishery. However, this level did not appear to be sufficient to sustain the levels of fishing mortality seen in the early 1990s. The issue of recruitment overfishing was partially addressed in 1992/93, but it was not until 1993/94 that a package of management measures was introduced in an attempt to promote lobster survival and rebuild the breeding stock to levels seen in the late 1970s to early 1980s - levels where it is known that only environment influenced the numbers of pueruli settling. The elements of the package included (1) a temporary pot reduction of 18% (pot usage of 82%); (2) having due regard for the lucrative export market where small lobsters achieved the best price, an increase in the legal minimum size of 1 mm CL from 76 to 77 mm CL for the first 2.5 months of the season; (3) a total ban on all female lobsters with either ovigerous setae or a spennatophore to complement the ban on berried females; and (4) the imposition of a maximum size limit of 115 or 105 mm CL, depending on the area being fished. This was due to population size-structure differences from north to south. The intent of the pot reduction was to reduce the overall exploitation rate and reduce fishing mortality. The increase in the legal minimum size served two purposes. The first was to allow more of the highly vulnerable, migrating, immature ‘whites’ to disperse into the deeper water breeding grounds, where they become less catchable and form part of the breeding stock in a year or two. The second reason was that the ‘whites’ catch traditionally had provided some 40-60% of the total annual catch, most of it landed in December. The increased minimum size allowed more ‘whites’ to survive and subsequently to moult, so a proportion would be caught at a larger size in the ‘reds’ fishery (second part of the season) and subsequent seasons. This had the effect of smoothing the catch over the season and gave processors the best opportunity to gain maximum return from the market. The ‘setose’ rule, as it became known, had a significant impact on the survival of all mature females and some immature females that had precocial development of ovigerous setae. This regulation allowed only a small window of opportunity for mature, female lobsters to be caught when they moulted into a ‘non-setose’ condition where ovigerous setae and spermatophore had been discarded with the old exuviae. The final element, the maximum size limit, was designed to boost the very low number of very large females in the population to reduce the dependence for egg production on the youngest mature age classes.

Reproductive Biology: Issues for Management

267

Since females require males of approximately equal, or larger, size for successful mating (Chittleborough, 1974), this measure raised the question of the impact of differential fishing mortality on mature male spiny lobsters. The judgement was that enough males would survive to reach the size required to mate with the growing number of females above the maximum size limit, for two reasons: the rapid growth of mature males (R.S. Brown, Western Australian Marine Research Laboratories, North Beach, WA, Australia, pers. comm.) and the ability of these males to mate with many females (Chittleborough, 1974). The at-sea commercial catch monitoring programme would provide early warning of any unmarked large females. Improved recruitment to the breeding stock and, essentially, full protection of mature females had spectacular results, with the target levels of egg production being attained over a 5-year period (Fig. 14.5). The target was reached with minimal noticeable decline in catch, even with reduced levels of recruitment to the fishable stock in four of the five seasons to 1997/98. Because all of the elements of the package operate in concert with one another, the effects of individual components are difficult to assess. Nonetheless, computer modelling has been undertaken to

0.25

X

3.- 0.15

I

!

)-North

+South

+BSS

Coast -Mn

Required Level

1

Fig. 14.5 Time series of spawning stock indices for the western rock lobster fishery. Indices from fishery data for the northern (+) and southern (W) coastal sectors of the fishery are compared with the fishery-independent breeding stock survey index (IBSS) (A)derived from research surveys. Solid horizontal line is the target level of egg production set with the introduction of the management arrangements in the 1993/94 season and which were extended through to the current season (1999/2000).

268 Spiny Lobsters: Fisheries and Culture

determine those impacts and the uncertainty around the estimates (N.G. Hall, unpubl.). The sustainability of the fishery is ensured, however, nominal fishing effort continues to creep to higher levels and the fishery still has considerable latent capacity to increase effective effort. No doubt there will soon be another quantum leap in technology that will be embraced by the fishery, further increasing the exploitation rate. It is useful to note that the introduction of quota management was mooted but the strong concensus throughout the lobster industry was to remain with input controls.

14.7

Conclusions

Competition between fishers generates more efficient fishing units taking a greater proportion of the available stock, which may in turn lead to severe reductions in the spawning potential of the stock. Specifically, in the field of reproductive biology, scientists must be able to determine the impact of fishing on population fecundity. They must also attempt to understand the underlying stock and recruitment relationship. Without these data fisheries managers must apply measures that will always be very conservative. The availability of results of research and modelling processes discussed in this chapter allows fisheries scientists to provide sound advice to the managers of spiny lobster resources.

References Aiken, D.E. & Waddy, S.L.(1980) Reproductive biology. In The Biology and Management of Lobsters, Vol. I, Physiology and Behaviour (Ed. by J.S. Cobb & B.F. Phillips), pp. 215-76. Academic Press, New York, USA. Aiken, K.A. (1977) Jamaica spiny lobster investigations. In Cooperative Investigations of the Caribbean and Adjacent Regions - II Symposium on Progress in Marine Research in the Caribbean and Adjacent Regions. F A 0 Fish. Rep. NO. 200, 11-22. Anndla, J.H. (1977) Effects of increases in the minimum legal size on the Otago rock lobster fishery. Fish. Res. Div. Occ. Publ. No. 13, 16 pp. Annala, J.H. (1983) New Zealand rock lobsters: biology and fishery. Fish. Res. Div. Occ. Publ. No. 42, 36 pp. Annala, J.H. (1991) Factors influencing fecundity and population egg production of Jasus species. In Crustacean Issues 7. Crustacean Egg Production (Ed. by A. Wenner & A. Kuris), pp. 3013 15. Rotterdam, The Netherlands. Annala, J.H. & Breen, P.A. (1989) Yield- and egg-per-recruit analyses for the New Zealand rock lobster, Jasus edwardsii. N . Z . J. Mar. Freshwat. Res., 23, 93-105. Annala, J.H. & Bycroft, B.L. (1987) Fecundity of the New Zealand rock lobster, Jasus edwardsii. N.Z. J . Mar. Freshwat. Rex, 21, 445-55. Annala, J.H., McKoy, J.L.,Booth, J.D. & Pike, R.B. (1980) Size at the onset of sexual maturity in female Jams edwardsii (Decapoda: Palinuridae) in New Zealand. N . Z . J. Mar. Freshwat. Res., 14, 217-27. Anon. (1985) Lobster catch rates compared. Southwest Fisheries Center, NMFS, NOAA, Report of Activities September-October 1985, p. 2.

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Trendall, J.T. & Prescott, J.H. (1989) Severe physiological stress associated with the annual breeding emigration of Panulirus ornatus in the Torres Strait. Mar. Ecol. Prog. Ser., 58, 29-39. Vega, A. (1991) Reproductive pattern of the spiny red lobster (Panulirus interruptus Randall 1840) on the west coast of the Baja California Peninsula and the variations of it in space and time in relation to the regulation of the exploitation of it (closed season). Secretaria de Pesca, Instituto Nacional de la Pesca, CRIP La Paz, Internal Document, 19 pp. Villegas, L., Jones, A.C. & Labisky, R.F. (1982) Management strategies for the spiny lobster resources in the western central Atlantic: a cooperative approach. N. Am. J. Fish. Manage., 2, 216-23.

Walters, C.J. (1986) Adaptive Management of Renewable Resources. McMillan, New York, USA, 374 pp. Walters, C.J. & Collie, J.S. (1988) Is research on environmental factors useful to fisheries management? Can. J. Fish. Aquat. Sci., 45, 1848-54. Walters, C.J., Hall, N.G., Brown, R.S. & Chubb, C.F. (1993) A spatial model for the population dynamics and exploitation of the Western Australian rock lobster, Panulirus cygnus. Can. J . Fish. Aquat. Sci., 50, 1650-2. Warner, R.E., Combs, C.L. & Gregory, D.R. (1977) Biological studies of the spiny lobster, Panulirus argus (Decapoda; Palinuridae), in south Florida. Proc. Gulf Carib. Fish. Inst., 29, 166-83.

Williams, G.C. (1986) Management of the Australian trawl fishery during tropical rock lobster migrations in Torres Strait 198C1984. In Torres Strait Fisheries Seminar, Port Moresby, 11-14 February 1985 (Ed. by A.K. Haines, G.C. Williams & D. Coates), pp. 200-11. Australian Government Publishing Service, Canberra, Australia. Wilson, R.C. (1948) A review of the southern Californian spiny lobster fishery. CaliJ Fish Game, 34, 71-80.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 15

Puerulus and Juvenile Ecology M.J. BUTLER IV Deparimeni

of Biological Sciences. Old Dominion University, Norfolk,

V A 23529-0266, USA

W.F. HERRNKIND Depariment

of Biological Science, Florida Siate University,

Tallahassee, FL 32306, USA

15.1

Introduction

The economics of commercial fisheries and the need for biological knowledge important for the effective management of those fisheries continue to fuel the majority of research on the ecology of palinurid early life stages. Recruitment dynamics and stock forecasting are of continued interest and obvious necessity for the sustainable management of spiny lobster populations world-wide, and our understanding of puerulus and juvenile ecology has benefited from these efforts. The need for practical fishery management solutions should not, however, overshadow the pursuit of basic scientific information. In his opening address at the Fifth International Conference and Workshop on Lobster Biology and Management in New Zealand in 1997, Professor J. Stanley Cobb said: ‘We have important things to learn in ecology, in physiology, and in evolution from lobsters, and this goes well beyond, while continually feeding back to, the fisheries that support much of the work’. This rings especially true for those life-history stages - phyllosoma, puerulus, and juvenile - that are not directly subject to fishing. Over the past few years, the development of new techniques in tagging and biochemical analysis of nutrition, among others, coupled with innovative experiments and careful statistical analysis, have shed new light on the many previously unanswered questions with respect to puerulus and juvenile ecology. However, most advances in our knowledge continue to come from only a few well-studied species. For example, there are intriguing new findings about some of the factors regulating puerulus transport, survival and settlement, particularly for Panulirus argus and P . cygnus. Despite these advances, for many species and in many regions, the kinds of habitats or microhabitats that serve as settlement substrates and subsequent juvenile nurseries remain a mystery. The success story in Western Australia where recruitment of juveniles to the fishery can be predicted from the supply of pueruli has continued with improved forecasting techniques. Similar puerulus monitoring efforts world-wide, initiated because of the successes in Western Australia, are now entering their second decade. Research on shelter-mediated post-settlement survival of new recruits has flourished, particularly on P . argus, where the relative importance of puerulus supply versus shelter in determining recruitment strength

276

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277

appears to vary considerably among areas. Evidence demonstrating the widespread occurrence of ontogenetic changes in juvenile sociality, mobility and shelter requirements has also come to light over the past few years, along with experimental and theoretical support for causal mechanisms and the adaptive significance of such changes. This review of spiny lobster puerulus and juvenile ecology updates the review in the first edition of this volume and again focuses primarily on information published some 20 years ago. However, some older references are included where appropriate for coherence or where little new knowledge is available. This revision includes over 75 new papers that have been published since 1994. More than half of these papers were on P . argus, and most of the rest focused on three other species: P . cygnus, P . japonicus and J. edwardsii. Thus, the bulk of the discussion is limited to a few species for which there is sufficient information with which to formulate reasonably accurate life histories. Selected data for other spiny lobster species regarding settlement habitats and growth rates has been compiled in Tables 15.1 and 15.2 for comparative purposes. The authors have undoubtedly overlooked some papers in their search of the literature, particularly those in publications that are not peer reviewed, and therefore not easily obtained, or are written in a language other than English. For those omissions the authors apologize. Throughout this chapter, the term ‘puerulus’ is used when refering to the post-larval spiny lobster stage, ‘early benthic juvenile’ when referring to the first few shelter-restricted, benthic juvenile stages, and ‘juvenile’ when discussing all of the subsequent non-reproductive juvenile instars. A number of alternative names for the various life-cycle stages described for palinurids appears in the literature (Felder et al., 1985), but a consensus on stage-specific terminology has yet to emerge (but see Lavalli & Lawton, 1996).

15.2 15.2.1

Settlement Factors affecting puerulus supply to coastal nurseries

Understanding the dispersal patterns of palinurid phyllosome larvae, which can be transported for enormous distances during their prolonged larval period, is a difficult proposition and the focus of continuing study. A summary of the current state of knowledge on the dynamics of larval lobster ecology lies beyond the scope of this chapter on puerulus and juvenile ecology. Recent reviews on that subject may be found in other chapters in this volume. If one assumes a sufficient source of phyllosome larvae to coastal waters, then coastal advective processes (e.g. coastal currents, gyres, upwelling, internal waves and wind-driven surface features and fronts) along with puerulus behaviour and nutritional condition undoubtedly influence the arrival of pueruli to coastal nurseries. It appears likely that metamorphosis of phyllosoma to pueruli occurs

278 Spiny Lobsters: Fisheries and Culture Table 15.1 Settlement and early post-settlement habitat of spiny lobsters Species

Habitat

Branched/foliose red or brown macroalgae; occasionally seagrass and fouled mangrove roots Rock crevices amidst Panulirus cygnus seagrass or macroalgae Rock or coral crevices Panulirus guttatus Rock or coral crevices Panulirus homarus Panulirus interruptus Surfgrass (Phyllospadix) shoots or rhyzomes; foliose macroalgae Panulirus japonicus Algal-covered rock crevices; red or brown macroalgae

Panulirus argus

Panulirus ornatus Panulirus versicolor Jasus edwardsii

Rock crevices amidst colonial invertebrates and macroalgae Rock crevices

Depth

Source

1-3 m

Marx & Herrnkind (1985b) Holmquist et al. (1989) Acosta & Butler (1997)

1-5 m

Fitzpatrick et al. (1989) Jernakoff (1 990) Sharp et al. (1997) Berry (1971) Engle (1979)

<10 m ?

1 4m <10 m

<25 m ?

Rock crevices; sometimes < l o m associated seagrass-covered rock reefs or caves with brown macroalgae

Harada (1957) Yoshimura & Yamakawa (1988) Yoshimura et al. (1994) Norman et al. (1 994) Norman & Morikawa (1996) Dennis et al. (1997) George (1968) Kuthalingam et al. (1980) Kensler (1 967) Lewis (1977) Booth & Bowring (1988) Edmunds (1995) Butler et al. (in press)

near the shelf break, often at the edge of prominent coastal currents (e.g. Leeuwin Current, Kuroshio Current, Florida Current). It is there where late-stage phyllosomes are most concentrated and pueruli first appear in the plankton, although in low numbers (Yeung & McGowan, 1991; Montgomery & Kittaka, 1994; Phillips & Pearce, 1997; Yoshimura et al., 1999). Metamorphosis does not appear to be triggered by environmental cues, but instead proceeds only after the accumulation of sufficient energetic reserves to supply the needs of the secondary lecithotrophic puerulus stage (McWilliam & Phillips, 1997). Histological examination of hepatopancreas and associated fat body tissues (Takahashi et al., 1994; Nishida et al., 1999, biochemical analysis of metabolic demands and stored energy reserves (e.g. C:N ratio, FWA:DNA ratio; Lemmens, 1994a, b, 1995), and examination of morphological changes in the feeding structures (Wolfe & Felgenhauer, 1991; Lemmens & Knott, 1994) of phyllosoma and pueruli confirm the long-held belief

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Table 15.2 Estimated growth rates of spiny lobsters during the first year post-settlement

Species

Growth rate (mmCL/month)

Panulirus argus

4.2 3 3

Laboratory/

Source

L L

Olsen & Koblick (1975)

field

F

Panulirus cygnus

1 1

Panulirus homarus Panulirus interruptus Jasus edwardsii

1.5 1S - 3 3

Jasus lalandii

1.5

F

I

L

L

F L L, F

F

Witham et al. (1968) Lellis & Russell (1990)

Forcucci e f al. (1994) Phillips et al. (1977) Fitzpatrick et al. (1989) Berry (1 97 1b) Engle (1979) Lewis (1977)

McKoy & Esterman (1981) Annala & Bycroft (1985) Pollock (1973) Grobler & Noli-Peard (1997) Pollock (1973)

(e.g. Sweat, 1968) that the puerulus stage does not feed and relies on internal energy stores sequestered during the larval stage. The duration of the puerulus stage varies among species, but is typically less than 1 month and is strongly influenced by water temperature. Laboratory studies show that P. polyphagus pueruli may moult in as little as 2 4 days, while J . edwardsii, among other species, can take nearly a month to moult during the winter (see Booth & Kittaka, 1994). Panulirus argus pueruli moult into the first juvenile benthic instars in 7-10 days in summer (at >29"C) and 14-28 days in winter (at <20°C; Butler & Herrnkind, 1991; Field & Butler, 1994). Although temperature dependent, the duration of the post-larval period for P . argus and J. edwardsii is unaffected by chemical or structural cues released by the settlement habitat, at least for pueruli captured from the inshore plankton (Butler & Herrnkind, 1991; Booth & Stewart, 1993). Biochemical analysis of energy stores and measurement of metabolic rates indicate that P . cygnus pueruli persist for 14-22 days, depending on swimming activity (Lemmens, 1994b). An increase from 18 to 23°C cuts the duration of this stage in half (Lemmens, 1994b). Along-shore coastal currents and wind-driven surface currents enhance the onshore movement of pueruli in some regions. In Western Australia, much of the spatial and temporal interannual variation in settlement is caused by shifts in the flow of the southerly Leeuwin Current, which in turn is influenced by El Niiio southern oscillation events (Phillips & Pearce, 1991). In El Niiio years, the Leeuwin Current is weaker and settlement of pueruli on artificial collectors declines (Phillips & Pearce, 1991). Elsewhere, it is speculated that meanders in the Kuroshio Current

280 Spiny Lobsters: Fisheries and Culture (Kittaka, 1994; Yoshimura et al., 1999) and coastal gyres off Florida and the Bahamas (Lee et al., 1994; Acosta et al., 1997; Lipcius et al., 1998) influence the magnitude of P . japonicus and P . argus puerulus supply, respectively. Winds that set up onshore surface water flow also increase the supply of pueruli to coastal areas. Rain events, associated with westerly winds, are correlated with changes in the supply of P . cygnus pueruli in Western Australia (Caputi & Brown, 1993; Caputi et al., 1995). Winter winds from the north-east resulting in an onshore movement of surface water explain a small ( ~ 6 % ) but , significant amount of the variance in P . argus puerulus supply to the Florida Keys, the coastal oceanography of which is dominated by the swift-flowing Florida Current (Acosta et al., 1997). Along-shore winds from the south-east within Exuma Sound explained nearly 50% of the variance in the supply of P . argus pueruli to sites near Lee Stocking Island in the Bahamas (Eggleston et al., 1998). Behaviour also plays an important role in the shoreward migration of pueruli. The nocturnally active pueruli are capable swimmers, exceeding speeds of 10 cm/s (Calinski & Lyons, 1983), but how they orientate towards the shore is still a mystery. Based on microscopic examination of the sensory setae on the antennae of P . cygnus pueruli, Phillips & Macmillian (1987) suggested that pueruli might orientate towards far-field vibrations caused by breaking waves. However, more recent examinations of sensory setae on P . cygnus, P . interruptus and J . edwardsii have yielded only limited evidence that these setae are used for detecting nearby vibrations and virtually no evidence that they are used for navigation by far-field vibrations (Macmillan et al., 1992; Jeffs et al., 1997). The inshore arrival of the fast-swimming pueruli of several species of Panulirus is also tied to the lunar cycle, peaking at or just after the new moon when tidal currents are at their maximum (e.g. P . argus: Little, 1977; Little & Milano, 1980; Marx & Herrnkind, 1985a; Heatwole et al., 1991; Bannerot et al., 1992; Acosta et al., 1997; Eggleston et al., 1997; but see Ward 1989; P . japonicus: Norman et al., 1994; Yoshimura et al., 1994; Norman & Morikawa, 1996). Pueruli of several species have also been observed swimming near the surface (e.g. J . edwardsii: Booth & Bowring, 1988) and collections of P . argus pueruli in plankton nets are greatest in the top 1 m of water (Little, 1977). These traits - nocturnal swimming near the surface during the new moon presumably serve to speed the pueruli across coastal currents and past risky habitats occupied by visually-hunting predators. However, little is known about sources or rates of mortality for pueruli. Gracia & Lozano (1980) reported finding P . gracilis and P . inflatus pueruli in the stomachs of a bottom fish (Netuma platypogon) off the Pacific coast of Mexico and pueruli of P . argus have been found in the stomachs of squirrelfish (Holocentrus spp.) off Bermuda (J. Ward, Bermuda Dept of Agriculture, Fisheries, and Parks, pers. comm.) and in the mouths of clupeid fish (Acosta & Butler, 1999). Acosta & Butler (1999) recently tested in field and mesocosm experiments whether the inshore migration of P . argus pueruli in surface waters during the new moon influenced their survival in various coastal habitats. Their

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results indicate that these behaviours do indeed reduce the risk of predation to pueruli in coastal waters, except over coral reefs where predator-prey encounter rates are high and the optimal strategy may be simply to avoid or rapidly transit that dangerous zone. However, not all species of spiny lobster capitalize on the fast tidal currents and low light levels present during the new moon. Jasus edwardsii, for example, arrives inshore in New Zealand and Australia during all lunar phases (Hayakawa et al., 1990; Phillips & Booth, 1994; Edmunds, 1995). Unfortunately, there is little published information on lunar settlement patterns for most other palinurids, and the data for some are contradictory. Serfling & Ford (1975), for example, found no lunar periodicity in the settlement of P . interruptus pueruli in California, whereas Guzman-Del Pro0 et al. (1996) report distinct settlement peaks just down the coast in Baja Mexico. Why some species exhibit distinct lunar periodicity in settlement while others do not is still an unresolved question. Physiological stressors related to poor water quality or nutrition may be another important source of mortality for pueruli. The pueruli of P . argus, for example, are intolerant of non-oceanic salinities, especially at extreme temperatures (i.e. below 22 or above 30°C; Witham et al., 1968; Field & Butler, 1994), which can be a problem in embayments that border large land masses where these factors might reach lethal levels. It is not known whether diseases affect pueruli.

15.2.2

Spatiotemporal patterns of puerulus supply

Settlement of many species is recorded by sampling pueruli and recently moulted early benthic juveniles on collecting devices ranging from artificial seaweed (Witham et al., 1968; Phillips. 1972) to artificial crevices (Booth, 1979a; Booth et al., 1991). Phillips & Booth (1994) provide a thorough review of the design, use and effectiveness of a variety of puerulus collectors, many of which have been used sucessfully to monitor spatial and temporal patterns of settlement. Although usually deployed in shallow water (<5 m deep), Booth et af.(1991) have recorded settlement of J . edwardsii on colectors at a depth of 50 m and there are records of P . argus settlement on collectors at 33 m depth (Heatwole et al., 1991; M. Butler & W. Herrnkind, unpubl. data). There have also been attempts to monitor settlement in natural habitat (Booth & Bowring, 1988; Fitzpatrick et al., 1989; Jernakoff, 1990; Herrnkind & Butler, 1994), but the high crypticity and low density of newly settled palinurids have prevented common use of such techniques. The development of puerulus collectors tuned to each species has been essential for monitoring post-larval supply and, ultimately, recruitment to fisheries worldwide. Often a device developed for one species is ineffective for another, but when new types of collectors are employed one must take care in standardizing methods to ensure quantitative comparisons of post-larval supply among localities (Phillips & Booth, 1994). This seems especially important for species like P . argus, P . ornatus, P .

282 Spiny Lobsters: Fisheries and Culture homarus, P . interruptus and J . edwardsii and others that range over wide geographical areas and political boundaries where numerous agencies and investigators are likely to work. The most abundant information on spatial and temporal settlement patterns again comes from studies of P. argus in the Caribbean, P. cygnus from Western Australia and J. edwardsii in New Zealand. For P. cygnus, an index of settlement is used to predict the commercial catch 4 years in advance (Phillips, 1986; Caputi et al., 1995). A knowledge of the patterns of P. cygnus supply is therefore vital to the wellbeing of the commercial fishery. Panulirus cygnus settles throughout the year with settlement peaks generally between September and January (spring-summer). In general, there has been a good correlation in puerulus supply among sites along the Western Australian coast (Phillips and Pearce, 1991), but following the poor prediction of the 1991/92 fishery catch based on puerulus catch measured in one region, a regional monitoring and catch estimation programme was established to account for regional variation in both post-larval supply and potential density-dependent post-settlement processes (Caputi et al., 1995). The seasonal supply of J . edwardsii pueruli to the New Zealand coast, monitored at up to 40 sites, has been relatively consistent over the past few decades (Booth, 1980, 1989; Booth & Tarring, 1982). Settlement is greatest along the east coast of the central North Island and varies considerably among regions along the coast, but shows remarkable concordance within a region. Most settlement typically occurs during winter, although the primary settlement season varies among regions. At Castle Point, for example, there are two seasonal peaks in J. edwardsii settlement, the stronger being in May-June (winter) with a weaker one between December and February (summer) (Booth & Tarring, 1986). The reasons for the regional and seasonal variations in settlement are unknown. However, puerulus settlement on nearshore collectors are associated with the abundance of mid- and late-stage phyllosomes in plankton samples and major offshore current patterns. These largescale ocean features probably influence puerulus supply in a similar manner along vast stretches of coastline. The supply of P. argus pueruli into nearshore areas was first monitored in south Florida over 30 years ago using ‘Witham’ collectors (Witham et al., 1968). Since then, various monitoring efforts have been conducted in Florida and elsewhere in the Caribbean and Western Atlantic (e.g. Antigua, Bermuda, Bahamas, Mexico, Jamaica, Puerto Rico and Martinique) (e.g. Little, 1977; Little & Milano, 1980; Mam & Herrnkind, 1985b; Herrnkind et al., 1988; Ward, 1989; Heatwole et al., 1991; Bannerot et al., 1992; Briones-Fourzan & Gutierrez-Carbonell, 1992; Butler & Herrnkind, 1992a; Briones-Fourzan, 1994; Forcucci et al., 1994; Acosta et al., 1997; Eggleston et al., 1998; Ricelet, 1998). When of sufficient duration, these studies indicate that P. argus pueruli arrive inshore year-round during or shortly after the new moon. The highest and most consistent catches are made in collectors anchored nearshore in shallow water (1-2 m depth) on the oceanic side of inlets or embayments separating long shorelines.

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Substantial spatial variation sometimes occurs among collector catches during a single lunar pulse over distances of 5-20 km (Marx, 1986; Bannerot et al., 1992; Herrnkind & Butler, 1994; Briones-Fourzan, 1994; Eggleston et al., 1998; Ricelet, 1998). Seasonal peaks vary considerably across the broad geographical range of this species (see Briones-FourzLn, 1994), although some of this variation is probably artefactual, due to insuficient sampling durations. Several years of data are typically needed to determine repeatable seasonal patterns. Time-series analysis of 8 years of data from a site in Florida (the longest data series available for P. argus) reveal distinct annual and lunar cycles with peak seasonal settlement occurring in March in the Florida Keys (Acosta et al., 1997). High influxes of pueruli can occur outside the characteristic seasonal or lunar cycle, due at least in part to wind-driven changes in the coastal currents transporting pueruli (Acosta et al., 1997; Eggleston et al., 1998). Catches of P . argus on collectors within shallow bays providing nursery habitat are typically low and recent studies demonstrate that there is no consistent correlation in catch between floating collectors and benthic collectors composed of the same material (Herrnkind et al., 1988; Herrnkind & Butler, 1994; Eggleston et al., 1997). This suggests that the behaviour of pueruli changes upon entry into nursery areas, presumably reflecting their search and preference for benthic settlement substrates. Estimates of settlement density within natural macroalgal habitat range from one individual per 36 m2 (Marx 1983, 1986) to one per 5 m2 (Butler et al., 1997), and densities as high as one per 3 m2 have been recorded in arrays of benthic collectors (Herrnkind & Butler, 1994). Despite the widespread use of artificial collectors for monitoring the influx and settlement of pueruli, rarely has the abundance of pueruli obtained on collectors been equated with the abundance of pueruli in the plankton, or with those settled in nearby natural substrates - and for good reason. The paucity of pueruli available in plankton tows, along with their scarcity and cryptic nature once settled, make this a daunting, if not impossible task in most circumstances. However, the existence of narrow channels between islands leading from the ocean into shallow nursery areas, along with the discovery of the essential settlement habitat (red macroalgae) of P. argus (Marx & Herrnkind, 1985a, b), permitted these comparisons at sites in Florida and the Bahamas. The relationships among puerulus catch on Witham collectors and from plankton nets, benthic settlement on artificial devices, settlement in natural habitat, and juvenile recruitment at individual sites and over larger regions were first evaluated by Herrnkind & Butler (1994) in the Florida Keys. Puerulus abundance on Witham collectors and in stationary plankton nets deployed nightly in the channels were highly correlated. Settlement of pueruli on artificial benthic collectors at sites several kilometres downstream of the Witham collectors were also highly correlated. Sites with abundant settlement habitat (i.e. red macroalgae) and shelters for juveniles (e.g. sponges) generally attained the highest settlement. However, settlement was patchy and locally unpredictable at individual sites, presumably owing to small-scale variability in the delivery of pueruli to optimal sites. Remarkably similar results were

284 Spiny Lobsters: Fisheries and Culture subsequently obtained for P . argus recruiting to the eastern Bahamas (Eggleston et al., 1998), confirming the generality of these patterns and the utility of appropriately placed Witham collectors for estimating the planktonic abundance of pueruli and their settlement within the Caribbean.

15.2.3

Settlement habitat

Relatively little is known of the natural settlement habitat of many species of spiny lobster, in contrast to more abundant information available for the fishable adults and older juveniles. The sparsity, small size and crypticity of pueruli and early benthic stage juveniles (EBJ), as well as the complex topography of the microhabitat in which they reside, conspire to make the early post-settlement phases of nearly all spiny lobsters challenging to study. In general, the natural habitats that newly settled pueruli and EBJ seek are either dense vegetation (e.g. red or brown macroalgae, seagrass) ( P . argus: Marx & Herrnkind, 1985a; Herrnkind & Butler, 1986; P . interruptus: Serfling & Ford, 1975; Engle, 1979) or small holes in rocks or reefs scaled to their body size ( P . cygnus: Jernakoff, 1990; P . homarus: Kuthalingam et al.,1980; P.japonicus: Yoshimura & Yamakawa, 1988; Norman et al., 1994; Norman & Morikawa, 1996; P . ornatus: Berry, 1971a, b; Dennis et al., 1997; P . versicolor: George, 1968; J . lallandii: Pollock, 1973; P . guttatus: Briones-FourzCn & McWilliam, 1997; Sharp et al., 1997; J. edwardsii: Kensler, 1967; Lewis, 1977; Booth, 1979b; Booth & Bowring, 1988; Booth & Phillips, 1994; Edmunds, 1995; Butler et al., in press) (Table 15.1). Pueruli and EBJ P . cygnus on the Western Australian coast have been found in relatively shallow coastal areas (4 m deep) in holes, crevices, ledges and caves of limestone reefs (Fitzpatrick et al., 1989; Jernakoff, 1990). These shelters are often covered by seagrass or macroalgae (Jernakoff, 1990). Fitzpatrick et al. (1989) also reported finding a few EBJ in deeper water (to 30 m) and between plates of coral at the Abrolhos Islands, about 100 km off the coast of Western Australia. Jernakoff (1990) determined that the presence of a seagrass or algal covering over holes drilled in limestone blocks was significantly preferred over bare holes by P . cygnus. In addition, P . cygnus EBJ preferred deep to shallow holes and there was a positive relationship between body size and size of shelter. The apparent preference of EBJ for closely fitting shelters has also been reported for P . japonicus (Fushimi, 1978; Yoshimura & Yamakawa, 1988; Norman et al., 1994; Norman & Morikawa, 1996), P . versicolor (Kuthalingam et al., 1980), P . guttatus (Sharp et al., 1997) and J. edwardsii (Edmunds, 1995; Butler et al., 1999). On most reefs and rocky substrates, the distribution of J . edwardsii and P . japonicus pueruli and EBJ dwelling in rock holes is random and, at least for J. edwardsii, unrelated to settlement density as measured on nearby crevice collectors (Edmunds, 1995; Norman & Morikawa, 1996; Butler et al., in press). Settlement of J. edwardsii and P . japonicus may be enhanced by the presence of vertical objects, such as kelps or artificial structures (e.g. piers,

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ropes for aquaculture) (Yoshimura et al., 1994; S . Frusher, University of Tasmania, Hobart, unpubl. data). In south Florida, P . argus pueruli settle primarily in clumps of red macroalgae, especially Lauenciu spp., which grow profusely in the region’s protected shallow waters (Marx, 1983; Marx & Herrnkind, 1985a; Herrnkind & Butler, 1986). Their preference for bushy macroalgae is in large part attributable to the complex architecture of this habitat (Herrnkind & Butler, 1986; Serpa-Madrigal & Areces, 1995), which also explains the effectiveness of a wide range of artificial materials used in various versions of the Witham collector (e.g. carpeting, burlap, frayed rope and plastic-coated hog’s hair filter media; Phillips & Booth, 1994). Macroalgae such as Laurencia also often contain chemicals that retard grazers (e.g. parrotfishes), thereby reducing the possibility of habitat destruction or incidental ingestion of algal-dwelling lobsters. Puerulus supply varies independently of changes in macroalgal availability, which can be dramatic. This tends to increase variability in settlement density among locations and times (Herrnkind & Butler, 1994; Butler et al., 1997). Panulirus argus pueruli settle randomly with respect to one another (Herrnkind & Butler, 1994), and they remain solitary and asocial as EBJ (Childress & Herrnkind, 1996; Butler et al., 1997). Sedimentation reduces the availability of macroalgal-dwelling prey, and heavily sedimented habitats are avoided by pueruli and EBJ alike (Herrnkind et al., 1988). Some settlement of P . argus pueruli also occurs in other habitats, such as seagrass meadows or among the spines of sea urchins, although these are not the preferred settlement habitat for P . argus (Khandker, 1964; Davis, 1971; Herrnkind & Butler, 1986; Holmquist et al., 1989). In some regions, the sheer abundance of seagrass habitat as meadows covering many square kilometres suggests that it may harbour appreciable numbers of new settlers (Acosta, 1999), although subsequent EBJ survival is lower there (Herrnkind & Butler, 1986). Heavily fouled mangrove prop roots are also important areas for settlement in places such as Belize where shallow, vegetated habitat is scarce (Acosta & Butler, 1997). The broad tendency to settle into deep interstices apparently makes P . argus recruitment opportunistically successful across a wide array of habitats.

15.3

15.3.1

Post-settlement events Shelter use and movement by juveniles

Following settlement and a variable period spent as EBJ dwelling within vegetation or in small holes, juveniles [typically > 15-20 mm carapace length (CL)] then seek nearby crevice shelters (e.g. rock crevices, holes and ledges; undercut coral heads and sponges) more appropriately scaled to their body size (e.g. P . argus: Eggleston et al., 1990, 1997; Butler & Herrnkind, 1992b; Forcucci et al., 1994; Childress & Herrnkind, 1997; Butler & Herrnkind, 1997; J. edwardsii: Edmunds, 1995; Butler

286 Spiny Lobsters: Fisheries and Culture et al., in press; P. ornatus: Dennis et al., 1997; Skewes et al., 1997; P . cygnus: Jernakoff, 1990). Several studies using variously sized artificial shelters (casitas) designed after those used by fishermen to concentrate lobsters have shown that appropriately scaled shelters and aggregations of lobsters generally enhance the survival of late-stage juvenile and subadult P . argus that occupy them (Eggleston et al., 1990, 1997; Mintz et al., 1994; Arce et al., 1997; Sosa-Corder0 et al., 1998). Changes in the availability of natural shelters for juvenile P. argus in Florida caused by the mass mortality of sponges in the area, resulted in dramatic declines in juvenile abundance and altered their patterns of shelter use (Butler et af., 1995; Herrnkind et al., 1997). Early benthic juveniles (EBJ), rarely venture far from shelter. Panulirus argus, P . japonicus, P . guttatus, and J. edwardsii EBJ often remain in the same holes or macroalgal clumps day after day, moving only short distances away to forage at night (Norman et al., 1994; Yoshimura & Yamakawa, 1994; Norman & Morikawa, 1996; Sharp et al., 1997; Butler et al., in press). The daily movement of larger, crevice-dwelling juveniles is also fairly restricted (<25 m) and non-directional, but increases as they grow larger, and their aggregate movement over several months can approach several kilometres ( P . argus: Andree, 1981; Forcucci et al., 1994; Acosta, 1999; Schratwieser, 1999; J. edwardsii: A. MacDiarmid, unpubl. data). The availability of crevice shelters may limit the local abundance of juveniles of some species in a density-dependent manner, presumably through predation. Changes in the availability of natural shelters (i.e. sponges) for juvenile P . argus in Florida brought about by large-scale ecosystem change resulted in dramatic declines in juvenile abundance and patterns of shelter use (Butler et af., 1995; Herrnkind et af., 1997). Similarly, experimental manipulations of artificial shelters designed to mimic small, widely distributed natural shelters (i.e. sponges and small coral heads) showed that the availability of crevice shelters for juveniles can limit the recruitment of juveniles to the local population (Butler & Herrnkind, 1997; Herrnkind et al., 1997). Field surveys in the north-west Hawaiian islands also suggest that the abundance of juvenile P . marginatus is linked to the availability of high-relief habitat (Parrish & Polovina, 1994). Although habitat bottlenecks to juvenile recruitment can be shown to exist at some sites and at small spatial scales for these two species ( P . argus and P . marginatus), regional recruitment patterns are tied to the levels of both puerulus supply and habitat structure (Forcucci et al., 1994; Polovina et al., 1995; Butler & Herrnkind, 1997; Lipcius et al., 1998). For P. cygnus, whose nursery habitat (rock crevices) is less dynamic, there seems to be little evidence for density-dependent regulation of juvenile abundance through habitat bottlenecks. Although most studies of P. cygnus have focused on older juveniles (e.g. Chittleborough, 1974, 1975, 1976), Chittleborough & Phillips (1975) proposed that density-dependent processes acted on EBJ to limit their numbers on nursery reefs. Because of very high concentrations of individuals on some inshore reefs, density-dependent mortality was expected to be highest on newly settled animals. This hypothesis has been downplayed in recent years because puerulus

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settlement is highly correlated with juvenile abundance on nearby reefs (Jernakoff et al., 1994) and is also highly correlated with commercial catches 4 years later (Phillips, 1990). Thus, the holding capacity of the reefs has apparently not limited the survival of juvenile and juvenile lobsters within the existing settlement levels and environmental conditions. Similar results have been noted for J . edwardsii in New Zealand, where the settlement of pueruli off Stewart Island is correlated with subsequent juvenile abundance a few years later (Breen & Booth, 1989). The situation for other species is unknown.

15.3.2

Sociality

The social nature of adult palinurids has long been recognized, but recent experimental studies on P . argus and J . edwardsii now show that juvenile palinurids undergo dramatic ontogenetic changes in sociality that alter their aggregation patterns and use of shelters (Berrill, 1975; Childress & Herrnkind, 1994, 1996, 1997; Butler et al., 1997, 1999; Ratchford & Eggleston, 1998). Early benthic juveniles are asocial and dwell solitarily in vegetation or small holes. The size at which they emerge from shelters in settlement habitat is influenced by the presence of larger conspecifics (Childress & Herrnkind, 1996), but is approximately 15-20 mm CL. At this time, they also become social and begin to congregate in crevice shelters, drawn by chemical cues released by conspecifics (Ratchford & Eggleston, 1998; Butler et al., 1999). The advantages and mechanisms by which juveniles aggregate may vary among species or with the distribution of crevice shelters (Zimmer-Faust et al., 1985; Zimmer-Faust & Spanier, 1987). Although clearly attracted by the scent of conspecifics (Ratchford & Eggleston, 1998), den sharing by small juvenile ( 4 0 mm CL) P . argus in Florida nursery habitats rarely occurs more often than expected by chance, and does not appear to enhance the survival of individuals over those that dwell alone (Childress & Herrnkind, 1994, 1996, 1997). In P . argus, attraction to conspecifics via chemoreception is believed to aid den-seeking individuals in rapidly locating the typically scattered shelters present in south Florida (Childress & Herrnkind, 1994, 1996, 1997). This presumably reduces their exposure in the open to predators. Juvenile J . edwardsii undergo a similar ontogenetic change in their receptivity to odours released by conspecifics (Butler et al., 1999), resulting in significantly greater aggregation of juveniles > 40 mm CL (Edmunds, 1995; Butler et al., 1999). Crevice shelters are plentiful in J. edwardsii nursery areas and increases in aggregation with juvenile size correspond with increased protection from predators. That is, small juveniles do not survive better in groups, but larger juveniles do. Anecdotal evidence suggests that similar ontogenetic changes in sociality probably occur in other aggregating palinurids.

288 Spiny Lobsters: Fisheries and Culture 15.3.3

Mortality

Potential factors causing mortality of juveniles include unsuitable shelter, lack of food, cannibalism during moulting, predation, disease and poor water quality. Very few studies have actualy identified significant sources of mortality for juvenile spiny lobsters and studies of P . cygnus and P . argus are again the most extensive. Predation has been strongly inferred as a major source of mortality for juvenile P . cygnus. Howard (1988) showed that several species of coastal reef fish were significant predators of EBJ. By sampling the stomach contents of fish, he found that predation on juvenile P . cygnus was concentrated on EBJ between 8 and 15 mm CL and that predation occurred at all times of the day. Although assessment of the proportion of mortality due to fish was restricted because of the lack of adequate information on densities of both fish and EBJ, Howard (1988) conservatively estimated that fish annually removed thouands of EBJ per hectare. Predation, mainly by fishes, is also thought to be the primary cause of mortality for juvenile P . argus. Predators of EBJ and juvenile P . argus include a wide array of fishes and elasmobranchs, as well as octopods and portunid crabs (Smith & Herrnkind, 1992). Along with the direct effect of predation, octopus can also indirectly affect the shelter use and local distribution of juvenile P . argus, which use chemoreception to detect and avoid octopuses (Hansen & Butler, unpubl. ms). Rubble areas adjacent to coral reefs and the reefs themselves are particularly dangerous places for new settlers (Acosta & Butler, 1997, 1999; Acosta, 1999), and recently settled, transparent and pigmented post-larvae are equally susceptible to benthic predators. Predation on EBJ P . argus residing in vegetation is minimized by the architectural complexity of the habitat, lobster camouflage and their solitary nature (Herrnkind & Butler, 1986; Smith & Herrnkind, 1992). Clumping of P . argus EBJ at scales <1 m, for example, nullifies the advantages of camouflage and crypticity, resulting in higher rates of predation (Butler et al., 1997). However, natural clumping of EBJ P . argus is rare, and mark-recapture experiments in areas where settlement was experimentally enhanced indicate that less than 5% of the settlers survive the EBJ stage and that survival is density-independent (Butler et al., 1997; Herrnkind et al., 1997). Predation rates decrease as juveniles grow, but larger juveniles ( 2 M O mm CL) remain a prominent component of the diet of larger fishes, especially bonnethead sharks (Sphyrna tiburo), nurse sharks (Ginglymostoma cirratum) and groupers (Epinephelus spp. and Mycteroperca spp.) (Cruz et al., 1986; Eggleston et al., 1990, 1997; Smith & Herrnkind, 1992; Schratwieser, 1999). Therefore, the availability of appropriate shelter continues to play an important role in the survival of large juveniles. In seagrass meadows mixed with macroalgae, even modest increases in algal biomass, which increases the architectural complexity of the habitat, greatly enhance the survival of juvenile lobsters (30-75 mm CL) off the Caribbean coast of Mexico (Lipcius et al., 1998). Increases in seagrass biomass alone, however, were ineffective in protecting large juveniles.

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Large-scale changes in environmental quality can also be detrimental to juvenile spiny lobsters, as the following two examples illustrate. Along the south-east tip of Africa in Namibia and South Africa, seasonal and interannual variations in coastal upwelling create periodic blooms of phytoplankton. With the subsequent demise of these blooms, increased bacterial decomposition of the resulting organic matter and low concentrations of dissolved oxygen in bottom waters ensue (Bailey et al., 1985; Grobler & Noli-Peard, 1997). These low dissolved oxygen events spark an offshore exodus of juvenile and adult J. lalandii and reduce the growth of juveniles that remain (Pollock & Beyers, 1981; Bailey et al., 1985; Beyers et al., 1994; Grobler & Noli-Peard, 1997). Extreme events result in the mass mortality of lobsters. In recent years, plankton blooms in south Florida have resulted in the mass mortality of sponges over large regions, where the abundance of juvenile P . argus has consequently plummeted in response to the loss of sponge shelters (Butler et al., 1995). Microwire tag results showed that survival of EBJ is up to six times lower where crevice shelter is reduced by sponge loss (Herrnkind et al., 1997, 1999). However, unusually high post-larval supply to the entire south Florida region and shifts in shelter utilization at sites affected by the sponge die-off have moderated the effect of this event on the population as a whole (Herrnkind et al., 1997).

15.3.4

Feeding

Dietary analyses of the natural prey of juvenile spiny lobster have undoubtedly been made for many species, but the present authors know of published reports for P . argus, P . cygnus, P . interruptus and J. edwardsii only. Fitzpatrick et al. (1989) studied the natural diet of juvenile P. cygnus and found that the three most numerous identifiable dietary components, as measured by per cent fullness of the foregut (Joll & Phillips, 1984), were coralline algae, molluscs and crustaceans. There appeared to be significantly fewer coralline algae in the guts of intermoult animals than in other moult stages. Juvenile J . edwardsii <30 mm CL eat mostly ophiuroids and isopods, with increasing numbers of bivalves found in their diet as they grow; juveniles larger than 60 mm CL also consume crabs and urchins (Edmunds, 1995). The natural diet of algal-dwelling EBJ P . argus consists mainly of small molluscs and crusaceans, but includes a wide array of other invertebrates (Marx & Herrnkind, 1985a; Herrnkind et al., 1988). Laboratory feeding experiments reveal that these EBJ display no preference among the most commonly eaten molluscs (largely gastropods) and crustaceans (various amphipods and isopods), and that over 50 individual prey are typically consumed within 24 h (Herrnkind et al., 1988). Older juveniles eat a similar array of organisms but of increasingly larger size and species composition, reflecting an expanded range of foraging habitats (Andree 1981). Captive EBJ P . argus can be effectively maintained on a diet of live adult brine shrimp and mixed chopped fish and shellfish (Lellis & Russell, 1990).

290 Spiny Lobsters: Fisheries and Culture 15.3.5

Growth

Growth of juvenile spiny lobsters has been measured in both the laboratory and the field for a number of species, including P . cygnus (Chittleborough, 1976; Phillips et al., 1977, 1992; Fitzpatrick et al., 1989), P . argus (Witham et al., 1968; Olsen & Koblick, 1975; Cruz et al., 1986; Lellis & Russell, 1990; Phillips et al., 1992; Forcucci et al., 1994; Lozano, 1996; Sharp et al., in press), P . interruptus (Engle, 1979), P . homarus (Berry, 1971b), P . ornatus (Phillips et al., 1992), P . versicolor (Kuthalingam et al., 1980), J. edwardsii (Lewis, 1977; McKoy & Esterman, 1981; Annala & Bycroft, 1985; James & Tong, 1997) and J . lalandii (Pollock, 1973; Grobler & Noli-Peard, 1997) (Table 15.2). The recent development and implementation of microwire tags has been particularly useful new technology that has yielded field estimates of growth for juvenile P . argus, P . cygnus, and P . ornatus and, for the first time, field estimates of EBJ growth for P . cygnus and P . argus (Butler et al., 1997; Sharp et al., in press). A number of promising indices of biochemical condition has been tested with adult spiny lobsters (e.g. lipids: Cockcroft, 1997; blood protein serum: R. Musgrove, South Australian Research and Development Institute, Adelaide, South Australia, pers. comm.) and may prove useful for studies of EBJ and juvenile growth. However, the distinct physiology of the fast-growing, but vulnerable EBJ and juvenile stages may complicate the use of biochemical storage markers as indicators of growth, if most of the energy available is used for growth and little is stored (Lemmens, 1994b, 1995; Robertson et al., in press). Phillips et al. (1977) studied the growth of P . cygnus from the puerulus stage to 3 years of age, and later applied non-linear random-coefficient models to laboratory and field data to estimate growth more precisely. They found that temperature markedly affected growth, animals grew best on a diet of mussel flesh, growth was similar for individuals raised alone or in groups, and growth for field- and laboratory-reared animals was similar. Field observations (Fitzpatrick et al., 1989) of estimated CL of juvenile P . cygnus suggest that growth is rapid (-3 mm CL/ month) and variable between sites. Lipofuscin-based estimates of juvenile age from natural populations agrees with previous cohort-based age estimates, both of which indicate that juvenile P . cygus take 3-5 years to reach 76 mm CL, whereupon they enter the fishery (Sheehy et al., 1998). Laboratory studies of growth and the moult cycle of P . argus juveniles have been conducted under differing conditions of diet, temperature, salinity and rearing environments (Witham et al., 1968; Witham, 1974; Olsen & Koblick, 1975; Lellis & Russell, 1990; Robertson et al., in press). These studies collectively indicate that growth is strongly affected by temperature and diet. As an example, Lellis & Russell (1990) found that the highest growth occurred at 30°C and resulted in a sixfold weight increase in 10 weeks, compared to a twofold increase over the same period at 24°C; optimal feed (live brine shrimp) conversion was at 27°C. Many studies on the growth of juvenile P . argus have been conducted in the field (Davis, 1975, 1981; Lyons et al., 1981; Lyons & Kennedy, 1981; Waugh 1981; Hunt

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& Lyons, 1986; Davis & Dodrill, 1989; Forcucci et al., 1994). Growth of juveniles varies greatly among these studies conducted throughout the Caribbean and it is strongly affected by water temperature and injuries, but not sex. Panulirus argus and P. ornatus (Skewes et al., 1994) may achieve the fastest growth of all the palinurids. Early benthic juvenile P . argus grow as rapidly as 0.82 mm CL/week (Sharp et al., in press) and juveniles at up to 1.25 mm CL/week (Forcucci et al., 1994). Several estimates suggest that juveniles can reach maturity ( 4 0 % mature at 76 mm CL) in about 1.5 years after settlement (Olsen & Koblick, 1975; Davis & Dodrill, 1980; Forcucci et al., 1994).

15.3.6

Population regulation via post-settlement processes

Ultimately, the abundance of all spiny lobsters is tied to the number of new recruits arriving from offshore. However, in some species, the suitability of the nursery habitat can have a significant impact on post-settlement mortality and recruitment. The high natural mortality of EBJ and small juveniles (e.g. 4 0 mm CL) compared with larger lobsters and their dependency on crevice shelters may limit the recruitment of these species (e.g. P . argus, P . marginatus) in a density-dependent manner, presumably through predation. In contrast, nursery habitat structure has little influence on the population dynamics of other species (e.g. P. cygnus). Field experiments with tagged P. argus indicate that providing appropriately scaled artificial shelters designed to mimic small, widely distributed natural shelters (i.e. sponges and small coral heads) at the critical period when juveniles vacate algae to dwell in crevices increases their survival, and thus local recruitment (Butler & Herrnkind, 1997). In the same study, the addition of newly settled EBJ to some experimental sites to enhance settlement did not significantly increase juvenile densities. Other experimental attempts at bolstering P . argus recruitment through stocking of microwire tagged EBJ have also failed to achieve measurable increases in population abundance, even though tagged individuals can be recovered (Butler et al., 1997; unpubl. data). In addition, the placement of artificial structures at sites with ample natural shelter (Mintz et al., 1994; Arce et al., 1997; M. Butler & W. Herrnkind, unpubl. data) or at sites where post-larval supply is minimal (Ricelet, 1998) has little or only a minimal effect on local abundances of juveniles. These and other experiments suggest that post-larval supply and nursery habitat interact over different spatial scales to control recruitment. Whereas post-larval supply ultimately determines the potential for recruitment, an upper limit on local population size might be imposed by shelter scarcity and perhaps by predators. Therefore, small-scale experiments may very well show that the abundance of juvenile lobsters can be increased through the addition of artificical structures, but these results, obtained from experiments conducted over a limited geographical range and thus a limited range of natural conditions, may yield misleading conclusions when extrapolated to large regions (Forcucci et al., 1994; Butler &

292 Spiny Lobsters: Fisheries and Culture Herrnkind, 1997; Herrnkind et al., 1999). The use of spatially explicit population models (Butler, 1997; Butler et al., unpubl. ms; Stockhausen et al., unpubl. ms) or metapopulation models is a way in which results from many experimental studies may be scaled up to predict the effect of altered post-larval supply or habitat structure at the population level.

15.4 15.4.1

Significance of puerulus and juvenile ecology in management Forecasting of stocks from puerulus and juvenile indices

For species with complex life cycles, such as spiny lobsters, understanding recruitment requires information on larval (or post-larval) settlement and ontogenetic shifts in habitat requirements and availability that alter post-settlement survival and growth. We cannot greatly impact oceanic transport of larvae or postlarvae, nor can we be certain to influence management decisions in other nations wherever palinurid populations cross geopolitical boundaries. However, fishery scientists and managers can act to protect nursery habitats essential for spiny lobster settlement and juvenile development, and can seek multinational management strategies where necessary. Whilst the ecological requirements of the puerulus and juvenile stages of many species are poorly understood, they nonetheless represent the most promising points in the life cycle from which adult year class strength can be predicted, and their use complements catch- or adult population-based methods for stock assessment (Breen, 1994; Addison, 1997; Hilborn, 1997; Medley & Ninnes, 1997). Without question, the best known and most successful example of how fishery predictions may be derived from a pre-recruit index is that for P . cygnus in Western Australia. For years, the abundance of pueruli obtained from artificial collectors deployed along the coastline of Western Australia has been used to predict the stock and regulate fishery catch 4 years later (Morgan et al., 1982; Phillips, 1986). Those estimates have been continually improved by incorporating the effects of spatial structure, meterological events and coastal oceanography on puerulus supply (Caputi & Brown, 1993; Caputi et al., 1995). As with P . cygnus, prediction of other spiny lobster stocks or fishery catch may be improved by incorporating meso-scale to large-scale oceanographic or meterological phenomena that undoubtedly effect larval and post-larval transport ( P . marginatus: Polovina & Mitchum, 1992; Polovina et al., 1995; P . argus: Lipcius er al., 1998). Where post-settlement processes potentially disrupt the relationship between puerulus supply and adult population size, indices of juvenile abundance may be more useful for stock prediction. Standardized surveys of juvenile abundance in natural habitats and shelters (Pitcher et al., 1997) or in habitats enhanced with artificial shelters (Cruz et al., 1995) may be used, but these methods are still in their infancy and as yet unproven.

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Artificial enhancement of natural populations

Natural populations of spiny lobsters may potentially be enhanced through stocking of EBJ collected from puerulus collectors or by the deployment of artificial structures to shelter vulnerable juveniles. The success of each approach depends on the natural ecological limits to recruitment of the species (see ‘Population regulation via post-settlement processes’, 15.3.6 above) and the economic practicality of obtaining and releasing sufficient numbers of pueruli or placing numerous artificial shelters on the seafloor. There has been extensive research on ways in which to collect and rear pueruli and juveniles (e.g. Witham et al., 1968; Phillips, 1972; Lewis, 1977; Little, 1977; Booth, 1979a; Little & Milano, 1980; Lellis & Russell, 1990), but there has been very little research on transferral techniques and their effect on post-transfer survival and growth. Jernakoff (1990) carried out preliminary field studies on the effects of transfer and found that post-pueruli of P . cygnus often refused to enter shelters after transfer, although their response was affected by the release technique. Given potentially high rates of post-transfer predation (Howard, 1988; Jernakoff, 1990; Butler et al., 1997) further study of transferral techniques that maximize postsettlement survival is needed. Determining the appropriate type of shelter to be deployed is also a requisite step in situations where shelter enhancement may be desirable. Although no published studies have specifically compared results among a suite of potential artificial shelters, the natural shelter preference for a particular species and comparisons among studies employing a single type of shelter will frame an appropriate starting point. Clearly, shelters scaled to the body size of developing lobsters and ones that accommodate the ontogenetic social shift towards aggregation at larger juvenile sizes will successfully concentrate lobsters and improve their survival (Davis, 1985; Eggleston et al., 1990, 1997; Mintz et al., 1994; Arce et al., 1997; Sosa-Corder0 et al., 1998). Small, scattered artificial shelters that mimic the types of shelter used by the most vulnerable, small lobsters are most likely to alleviate demographic bottlenecks to recruitment (Arce et al., 1997; Butler & Herrnkind, 1997; Herrnkind et al., 1997, 1999). The additional presence of fewer large shelters may offer the necessary protection and space for the gregarious large juveniles and subadults. However, there is no evidence that lobster recruitment is enhanced solely by the use of large artificial shelters, like those commonly employed by fishermen. This chapter closes by emphasizing that the ecological ramifications of large-scale artificial enhancement efforts are unknown. Potentially serious impacts on spiny lobster populations, as well as to ecosystem trophic and habitat structure, could ensue from widespread application of these measures. Further field research is needed to evaluate fully the efficacy of artificial population enhancement techniques and their impact on the surrounding ecosystem before this approach is advocated. Even if none of the enhancement approaches is deemed tenable, the evidence

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obtained might well save wasted investment or prevent irreversible environmental damage.

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Smith, K.N. & Herrnkind, W.F. (1992) Predation on early juvenile spiny lobsters Panulirus argus (Latreille): influence of size and shelter. J. Exp. Mar. Biol. Ecol., 157, 3-18. Sosa-Cordero, E., Arce, A.M., Aguilar-Davila, W. & Ramierz-Gonzalez, A. (1 998) Artificial shelters for spiny lobster Panulirus argus (Latreille): an evaluation of occupancy in different benthic habitats. J. Exp. Mar. Biol. Ecol., 229, 1-18. Sweat, D.E. (1968) Growth and tagging studies on Panulirus argus (Latreille) in the Florida Keys. Florida Board Conservation Marine Research Laboratory Technical Series, No. 57. Takahashi, Y., Nishida, S. & Kittaka, J. (1994) Histological characteristics of fat bodies in the puerulus of the rock lobster Jasus edwardsii (Hutton, 1875) (Decapoda, Palinuridae). Crustaceana, 66(3), 318-25. Ward, J. (1989). Patterns of settlement of spiny lobster (Panulirus argus) postlarvae at Bermuda Proc. Gulf Carib. Fish. Inst., 39, 255-64. Waugh, G.T. (1981) Management of juvenile spiny lobster (Panulirus argus) based on estimated biological parameters from Grand Bahama Island, Bahamas. Proc. GulfCarib. Fish. Inst., 33, 271-89. Witham, R. (1974) Preliminary thermal studies on young Panulirus argus. Q. J . Flu Acad. Sci., 36, 1568.

Witham, R.,Ingle, R.M. & Joyce, E.A., Jr (1968) Physiological and ecological studies of Panuirus argus from the St. Lucy estuary. Florida Board Conservation Marine Laboratory Technical Series, No. 53. Witham, R., Ingle, R.M.& Sims, H.W., Jr (1964) Notes on postlarvae of Panulirus argus. Q. J . Flu. Acad. Sci., 27, 289-97. Wolfe, S.H. & Felgenhauer,B.E. (1991) Mouthpart and foregut ontogeny in larval, postlarval, and juvenile spiny lobster, Panulirus argus Latreille (Decapoda, Palinuridae). Zool. Scripta, 20, 57-75. Yeung, C. & McGowan, M. (1991) Differences in inshore-offshore and vertical distribution of phyllosoma larvae of Panulirus, Scyllarus, and Scyllarides in the Florida Keys in May-June 1989. Bull. Mar. Sci., 49, 699-714. Yoshimura, T. & Yamakawa, H. (1988) Ecological investigations of settled puerulus and juvenile stages of the Japanese spiny lobster Panulirus japonicus at Kominato, Japan. J. Crust. Biol., 8, 524-3 I . Yoshimura, T., Yamakawa, H. & Kozasa, E. (1999) Distribution of final stage phyllosoma larvae and free-swimming pueruli of Panulirus japonicus around the Kuroshio Current off southern Kyushu, Japan. Mar. Biol., 133(2), 293-306. Yoshimura, T., Yamakawa, H. & Norman, C.P. (1994) Comparison of hole and seaweed habitats of post-settled pueruli and early benthic juvenile lobsters, Panulirus japonicus (Von Siebold, 1824). Crustaceana, 66(3), 3 5 M 5 . Zimmer-Faust, R.K. & Spanier, E. (1987) Gregariousness and sociality in spiny lobsters: implications for den habitation. J. Exp. Mar. Biol. Ecol., 105, 57-71. Zimmer-Faust, R.K., Tyre, J.E. & Case, J.F. (1985) Chemical attraction causing aggregation in the spiny lobster, Panulirus interruptus, and its probable ecological significance. Biol. Bull., 169, 106-18.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 16

Stock Identity of the Red (Jasus edwardsii) and Green (Jasus verreauxz) Rock Lobsters Inferred from Mitochondria1 DNA Analysis J.R. OVENDEN' and D.J. BRASHER' Department

ofzoology, University of

Tasmania, P.O. Box 252C, Hobart 7001, Tasmania, Australia

12.1

Introduction

This chapter describes the most recent attempts to understand the stock identity of three commercially valuable southern hemisphere lobster species: the red rock lobster (Jasus edwardsii), the southern rock lobster (J. novaehollanidae = J . edwardsii, Booth et al., 1990) and the green or eastern rock lobster ( J . verreauxi), using mitochondria1 DNA (mtDNA) analysis. As this genetic technique is comparatively novel, this chapter also provides some background information on the use of mtDNA analysis as an investigative tool for fisheries biology. A more detailed account of this topic is given by Ovenden (1990) and Ward & Grewe (1994). The success of genetic analyses applied to lobster species in the past has been limited. Prior to studies of lobster mtDNA genetics, geneticists generally were unable to find a measurable, variable 'signal' within the lobster genome. These previous studies relied on the technique of allozyme electrophoresis to reveal nuclear gene frequency differences among populations of lobsters. It is beyond the scope of this work to describe the practice and theory of allozyme electrophoresis for marine stock assessement, but interested readers may consult Richardson et al. (1 986) and Hillis et al. (1996). In possibly the most comprehensive analysis of lobster allozymes performed to date, Shaklee & Samollow (1984) sampled 1869 spiny lobsters (Panulirusrnargilzatus) from seven localities throughout the Hawaiian Islands to test the hypothesis of genetic stock homogeneity. Only seven of 46 enzyme-coding loci were shown to exhibit detectable allele frequency variation. Among these seven loci, genetic variation was limited to two or three alleles per loci, with frequencies being highly skewed to one allele per locus. The remaining loci showed no allelic variation, or exhibited rare alleles with a frequency less than 1%. Across all loci, the average

'Current address: Southern Fisheries Centre, PO Box 76, Deception Bay, Qld 4508, Australia. 'Current address: 53c Devonshire Drive, London SElO 852, UK.

302

Stock Identity of the Red and Green Rock Lobsters

303

number of heterozygous loci per individual was 0.021. With these data, Shaklee & Samollow were unable to disprove genetic homogeneity of lobster throughout the Hawaiian Archipelago. In a follow-up study 7-9 years later, the degree of overall genetic homogeneity, and of individual heterozygosity, had remained unchanged (Seeb et al., 1990). The small amount of allozymic variation found in the Hawaiian spiny lobster was similar to that discovered in the American lobster (Hornarus arnericanus) by Tracey et al. (1975). In a study of 290 lobsters from eight localities on the west coast of the USA, the average number of heterozygous loci per individual was 0.038, slightly higher than the Hawaiian spiny lobster (0.021). Tracey et al. (1975) found 30 loci which were either monomorphic or essentially invariable by the criteria of Shaklee & Samollow (1984). Genetic variation was concentrated into five of the remaining 14 loci that were assayed. At one of these loci, malic enzyme, the frequencies of the two alleles were reported to vary among localities. For example, at two offshore localities (GBS and LSA) the alleles had almost equal frequencies. At two inshore localities (WHP and MVS) one allele predominated over the other, while at another locality the reverse was found. The authors suggest that these data may disprove genetic homogeneity between inshore and offshore populations of lobsters. Low levels of measurable allozymic variation were the main problem encountered by Smith et al. (1980) in their analysis of genetic homogeneity within the New Zealand red rock lobster (J. edwardsii) and between the red rock lobsters in New Zealand and Australia ( J . novaehollandiae). Among 185 lobsters from four localities in the two countries, an analysis of 33 enzyme-coding loci found that 24 were essentially invariable, as judged by the criteria used above. The amount of heterozygosity for red rock lobsters measured (J. edwardsii, 0.012; J. novaehollandiae, 0.028) was even lower than the equivalent for the Hawaiian and American lobsters. The two most variable loci were esterase-1 and lactate dehydrogenase-1. The frequencies of the two alleles at each of these loci were similar across all four of the localities sampled, as were the frequencies of the alleles at the less variable loci. In a possible exception to the genetic homogeneity generally found in lobster species, the allele lactate dehydrogenase-1 was less frequent in the Australian sample (0.686) compared with the mean of the three New Zealand sites (0.981). The alternate allele, lactate dehydrogenase-2, was correspondingly more frequent in the Australian sample (0.314) than in the New Zealand samples (0.019). However, in a systematic study which confirmed the lack of species distinction between red rock lobsters from New Zealand and Australia, Booth et al. (1990) were unable to find a significant difference between the frequencies of the lactate dehydrogenase alleles in lobsters sampled from a further seven localities from New Zealand and two from Australia. These three studies of commercially important species of lobsters (Hawaiian: Shaklee & Samollow, 1984; American: Tracey et al., 1975); Australian and New Zealand red: Smith et al., 1980) have been characterized by low levels of genetic variation measurable by allozyme electrophoresis. Consequently, the authors have not been able to make definitive stock analyses. Other species of decapods have

304 Spiny Lobsters: Fisheries and Culture

shown varying levels of genetic variation. Stevens (1990) has demonstrated that pea crabs (Pinnotheres novaezelandiae) from the North Island of New Zealand were monomorphic at only 34% (8/23) of loci assayed. In contrast, a mean of 86% of 37 loci was essentially monomorphic amongst I3 species of penaeid prawns from northern Australia (Mulley & Latter, 1980). Owing to a general lack of detailed analyses, it is not possible to determine whether low levels of allozymic variation are a general feature of lobster populations.

16.2 16.2.1

Usefulness of mitochondrial DNA for genetic analyses of stocks

Technique of mitochondrial DNA analysis

MtDNA has become a popular genetic system for analysis for numerous reasons. The genome is simple in structure and function compared with the immensely complex nuclear genome. Unlike the nuclear genome, elements of the mitochondrial genome do not mutually recombine during meiosis and all individuals carry mtDNA which is identical to that of their female parent (Brown, 1985). These features mean that, barring mutation events, a single type of molecule is inherited by successive generations and can be used to assess relatedness between populations. The application of mtDNA analysis to marine stock assessment has been described in detail by Ovenden (1990) and a brief summary of the technique is given here. MtDNA is a relatively small (16 000-20 000 nucleotide pair) genome found in multiple, identical copies in organelles, the mitochondria, which are present in all the body cells of an individual. The molecule differs between individuals generally not in size or composition, but in the order or linear sequence of nucleotide pairs which are the building blocks of all DNA molecules. The basic premise behind the use of the molecule for fisheries stock assessment is that individuals with the most similar mitochondrial genomes are the most closely related. The similarity between mtDNA molecules, extracted from individuals appropriately collected throughout the range of the proposed stock or stocks, is assessed using indirect and direct measures of nucleotide sequence variation among individuals. Specialized enzymes, called restriction endonucleases, are used to detect the location of certain sequences of nucleotides within a genome. A comparison of the location of these sequences between pairs of genomes gives a statistical estimate, as well as a qualitative measure, of the overall sequence similarity between the mtDNA of two individuals. Alternatively, the nucleotide sequence of a gene region 200-1000 base pairs long, amplified by the polymerase chain reaction, is determined directly by manual or automated sequencing (Hillis et al., 1996). In a fishery analysis, data from many hundreds of individuals may be collected. Inferences about genetic relatedness between pairs of individuals among and within populations are made from patterns of sequence similarity analysed with techniques adapted from the fields of population genetics and numerical taxonomy.

Stock Identity of the Red and Green Rock Lobsters 16.2.2

305

Strengths

The measurement of genetic difference between fisheries stocks is the great strength of mtDNA analysis. Its power in this application is derived from certain features of the evolutionary biology of the molecule: maternal inheritance and an apparently rapid rate of evolution. As a result of these processes, fisheries stocks are likely to possess their own unique mixture of mitochondrial genotypes. The rate at which stocks acquire differences, and the degree of separation which is achieved, depend on the stochastic survival of maternal lineages, the inherent mutation rate of the genome and the long-term effective population size (Avise, 1989). The rate of mammalian mtDNA evolution was estimated to be five to 10 times more rapid than equivalent part of the nuclear genome (Brown et al., 1979) and it was proposed that mitochondrial genomes may have an inherently less accurate duplication and repair mechanism. However, subsequent studies on sea urchins and flies show no major discrepancies between the rate of mitochondrial and nuclear DNA evolution (Moritz et al., 1987). Larger amounts of variation in the lobster mitochondrial compared with nuclear genomes may be a function of the population dynamics, and not the molecular biology, of the species. The mitochondrial genome does not have any known interaction with the environment, so that genetic variation between classes of individuals is thought to reflect truly the presence of reproductive isolation. Nucleotide sequence variation in mtDNA is completely independent of variation in allozymes of nuclear loci. It can, therefore, provide independent validation, or otherwise, of fisheries stock hypotheses derived from allozyme studies. Using qualitative characteristics of the mitochondrial genome, hierarchical relationships between fisheries stocks can be tested using cladistic or Hennigean methods. Under certain circumstances, the mitochondrial genome has the potential to reveal the presence of one-way movement of genes between populations. This has been demonstrated in studies of the genetics of hybrid zones between closely related species (Avise & Saunders, 1984; Tegelstrom, 1987). In these examples, individuals on one side of the zone of hybridization, which are morphologically and allozymically members of one species, have been shown to possess the mtDNA of the species with which hybridization is occurring. The presence of a particular type of mtDNA in these individuals indicates the occurrence of backcrossing lineages which not only perpetuate the ‘wrong’ type of mtDNA, but represent the possible invasion of nuclear genes from the opposing species. In a fisheries context, the presence of individuals with the ‘wrong’ type of mtDNA may indicate the presence of a previously unknown zone of hybridization. For the detection of gene flow between fisheries stocks, the usefulness of mtDNA analysis is only just being realized. There is the potential for patterns in mtDNA variability to reveal specialized types of movement of individuals between groups. For example, using mtDNA analysis Brasher et al. (1992b) confirmed the genetic distinctiveness of four species of southern ocean lobster (Jasus lalandii, J. tristani, J .

306 Spiny Lobsters: Fisheries and Culture verreauxi and J . edwardsii, Fig. 16.1). These species maintain allopatric distributions despite the possibility of genetic interchange mediated by widespread and long-term larval dispersal around the southern oceans (Phillips & McWilliam, 1986). mtDNA analysis could be used to test for the presence of post-settlement selection, a mechanism which may reinforce their allopatry. This type of selection may be operating against foreign juveniles to ensure that they never recruit into an adult population of a different species. The presence of juvenile lobsters which were a different species to local adults would be strong evidence in favour of the hypothesis. However, it is impossible to identify juvenile Jusus spp. lobsters, with the exception of J . verreauxi, to the level of species with morphological characters only. As it has been previously determined that each of the Jasus species has a recognizably different mitochondrial genome, mtDNA analysis of juveniles and adults from the same locales provides an accurate and convenient test of the hypothesis. Another type of gene flow which could be tested using mtDNA analysis is that of unilateral movement. This is relevant to the analysis of lobster stocks, for in the southern hemisphere at least, westerly populations are thought to contribute to easterly populations via movement of larvae in the west wind drift, but not vice versa. The results of an mtDNA study on lobster would support this hypothesis if there were genotypes in the easterly populations which were not found in the westerly populations, and all of the genotypes identified from the westerly population were also found in the easterly population. Such results could only be obtained following a stringent sampling programme because of the naturally skewed nature of mtDNA genotype frequencies. The overall amount of mtDNA variation within the westerly population would be less than in the easterly population, a result

J. adwarddl J. novmhollandlae

J. Ialandll

J. trlstanl J. verreauxl I

A

1v

8.0

1

I

1

I

I

I

1

I

3.O 2.0 1.o Nucleotide Sequence Divergence (%)

4.0

1

1

0.0

Fig. 16.1 Phylogenetic relationship between five species of Jaws rock lobsters as estimated by the UPGMA according to mitochondrial DNA sequence divergence. The horizontal bars within each species represent a mitochondrial haplotype. Adapted from Brasher et al., 1992.

Stock Identity of the Red and Green Rock Lobsters

307

which would normally be assumed to reflect differences in relative population size or age. However, a phylogenetic analysis of genotype similarities would show that the genotypes unique to the easterly population formed a distinct clade to the exclusion of the remaining genotypes from both easterly and westerly populations. For mtDNA analysis to be able to support a hypothesis of unilateral movement from west to east under these circumstances, there must be stable equilibria, within the eastern population, of localized and western recruitment. It would be constructive to test the usefulness of mtDNA for the detection of unilateral movement in a species in which there was overwhelming, non-genetic evidence for this type of gene flow.

16.2.3

Limitations

Mitochondria1 DNA is essentially a single genetic locus, being composed of several thousand nucleotides in complete linkage disequilibrium. As such, it can provide only a fraction of the picture of overall genetic variation in a group of animals. Allozyme gene variation also provides only a limited picture of overall genetic variation, but a decrease in allozyme variability is often taken as an indication of a decline in the ‘genetic’ health of the population. Similarly, a relative decrease in mtDNA sequence variation among a group of animals has been shown to indicate a recent bottleneck in the history of the population. Such an event may reflect reproductive isolation from other populations and may make that group of animals vunerable to exploitation (Lande, 1998). Analysis of mtDNA does not provide any information about the type of genetic variation controlling commercially important features of the population. The phenotypic effects of mtDNA sequence variation have been partially described for only one vertebrate species, the cutthroat trout (Forbes & Allendorf, 1991). It is currently not possible to use mtDNA variation in the lobster genome to predict any aspect of their phenotype. Techniques of quantitative genetics, such as breeding experiments and the field assessment of variation of characters which are possibly under genetic control, are needed to fill this void. This area of research is mostly neglected by genetic stock assessment studies, but is vitally important for aquaculture ventures. The mitochondria1 genome could be used as a genetic marker for maternal lines in selective breeding experiments (Gyllensten & Wilson, 1987). Analysis of mtDNA does not provide a definitive test for the presence of reproductive isolation within or between fisheries stocks. If a group of animals composing a fisheries stock are shown to have an underlying pattern to their mtDNA variation, then it is likely that some degree of reproductive isolation is present between them. However, if no pattern can be demonstrated to explain mtDNA variation, or if there is little or no measurable mtDNA variation, it does not necessarily mean that groups of animal are not reproductively isolated. Unfortunately for the cause of fisheries genetics, there are many reasons why reproductive isolation can remain hidden despite a detailed and thorough investigation of

308 Spiny Lobsters: Fisheries and Culture

mtDNA variation (Ovenden, 1990). In brief, some of the more important reasons may be: that the magnitude of genetic differentiation between stocks is below the resolution of the type of mtDNA analysis used, that genetic divergence between stocks has occurred too recently for the event to be reflected by the mitochondrial genome or that genetic divergence is masked by natural selection favouring mitochondrial genotypes which may be common to both stocks. However, mtDNA is a powerful tool for stock discrimination, especially when combined with other techniques, such as microsatellite analysis (O’Connell & Wright, 1997). 16.3 Case study: Mitochondria1 DNA analysis of the red (Jusus edwurdsii) and green (Jusus verreuuxi) rock lobsters

This study uses the within-species genetic variation of the mitochondrial genome of the red and green rock lobsters to test the hypothesis of genetic homogeneity throughout their adult ranges and is a synthesis of Ovenden et al. (1992) and Brasher et al. (1992a). In particular, the presence of genetic homogeneity was tested for between geographically separated groups of adult and late juvenile lobsters in the same period. No attempt was made to compare the mitochondrial genomes from lobsters collected from the same, or different, localities throughout the year, or in successive years. Adult and late juvenile populations of the red and green rock lobsters have disjunct distributions on the eastern and western margins of the Tasman Sea. Red rock lobsters are distributed across the continental shelf of southern Australia and on most rocky shorelines in New Zealand, particularly on the south-west coast of the South Island and on the Chatham Islands (Holthuis, 1963; Kensler, 1967). Green rock lobsters have a more restricted and more northerly distribution. They are principally found along the coast of New South Wales, Australia (George, 1966), and on the north-east coast of the North Island of New Zealand (Kensler, 1967). Although the lobster larvae are long lived and have been found alive in the water column long distances from adult habitat, some authors have expressed doubt as to whether widely dispersed larvae successively recruit into distal adult habitat (Johnson, 1971; Phillips & McWilliam, 1986). The Tasman Sea may be a barrier to exchange between eastern and western red and green rock lobster populations, in which case they may not be genetically homogeneous. Similarly, localized mechanisms of recruitment may be responsible for creating and maintaining a lack of genetic homogeneity between adult populations of the red rock lobster across the expansive coastline of southern Australia. The absence of genetic homogeneity would imply the presence of partially or fully reproductively isolated populations of lobsters. From the spatial pattern of genetically defined populations it may be possible to map the locations of possible

Stock Identity of the Red and Green Rock Lobsters

309

barriers to gene flow. Genetic homogeneity hypotheses amongst populations of the red rock lobster have been the target of at least one other study (Smith et al., 1980), but the genetic system chosen, allozyme variation at nuclear genes, was unsuitable because of its inherent lack of polymorphism. Analysis of mtDNA was chosen for this study as Brasher et al. (1992a) had previously shown that mtDNA sequence polymorphism between and within four species of Jasus was comparatively high. The nature of reproductive barriers to gene exchange between lobster populations identified in this study, and their geographical range, would be an important target for future genetic and non-genetic analyses. The information gained would be essential raw data for long-term exploitation strategies. The red, and to a lesser extent, the green rock lobster forms the basis of an extensive capture fishery in southern Australia and New Zealand (Chapters 1 and 2).

Methods

16.3.2

Late juvenile and adult red and green rock lobsters were sampled once from 16 locations in Australia and New Zealand between April 1989 and June 1990 (Fig. 16.2). Red rock lobsters were taken from the western extent of their range (Esperance, Western Australia, n = 15). A single sample was taken from Spencers Gulf at Port Lincoln, South Australia (10). On the western coast of Victoria, lobsters were sampled at two localities (Bucks Bay, 8; Port Fairy, 10). Three locations in Bass Strait were chosen: King Island (10) and Temma (11) in western Bass Strait, and Flinders Island (10) to the east. Around the southern and eastern coast of Tasmania, lobsters were taken from Flying Cloud Point (16), Sullivans Point (13) and from Bicheno (6). Red rock lobsters from the most northerly extent of their range were sampled from Batemans Bay in New South Wales (4).In New Zealand, red rock lobsters were also taken from Gisborne (10) on the east coast of the North Island and from Moeraki (9) on the east coast of the South Island. Green rock lobsters were

AUSTRALIA

-

30°

Esperance 4O0

Port Lincoln Bucks Bay-

-

Point

Flying Cloud Point'

50" S

I 1200

I 140"

I 1800

0

I 180'E

Fig. 16.2 Locations from which red (Jasus edwardsii, 13 locations) and green ( J . verreauxi, three locations) rock lobsters were sampled for mitochondria1 DNA analysis.

3 10 Spiny Lobsters: Fisheries and Culture

sampled from Era Beach (8) on the coast of New South Wales and from Matakaoa Point (9) and North Cape (8) on the western coast of the North Island, New Zealand. From each freshly killed lobster, the pair of antenna1 glands was removed and stored in liquid nitrogen until needed for experiments. This tissue had previously been determined to yield mtDNA of the highest purity and concentration using an adaptation of the differential centrifugation, lysis and organic extraction method of Chapman & Powers (1984) and Brasher (1992). A map of the relative locations of six types of hexanucleotide sequences (restriction sites) was made for the red rock lobster mitochondria1 genomes using the double-digestion technique (Ovenden et al., 1992). The restricton enzymes which corresponded to those restriction sites were AfnI (recognition site CTTAAG), AvaI (CPyCGPuG), Ban1 (GGPyPuCC), BstYI (PuGATCPy), EcoRV (GATATC) and Hind111 (AAGCTT). During these experiments, lobster mtDNA was cleaved with the restriction enzymes, the fragments were radioactively labelled, separated according to size with agarose electrophoresis and visualized with autoradiography (Brasher et al., 1992b). Two methods for detecting a possible departure of red and green rock lobster genetics from overall homogeneity have been used. The first is gene diversity analysis, and the second involves the detection of a correlation between genetic similarity and geographical proximity. A brief outline of each method is given here for readers who are unfamiliar with either population genetic or phenetic clustering theory. A more thorough analysis of the data set, using a wider range of techniques, can be found in Ovenden et al. (1991) and Brasher et al. (1992a). Populations of animals are assumed to choose mates randomly. In reality, however, most animals have a limited choice of mates. An obvious feature of natural populations which affects mate choice is the division of the population into subunits which are created by physical or biological barriers to dispersal. Mating between individuals within each subpopulation will be more frequent than mating between individuals in different subpopulations. Such a mating system gives rise to an inbreeding-like effect. The principal effect of inbreeding is to increase the frequency of homozygotes, usually accompanied by a decrease in the degree of genetic variation. In a gene diversity analysis, the average amount of genetic variation within putative subpopulations of lobsters is compared with the overall amount of genetic variation among all individuals sampled. If the two quantities are equal, the index of gene diversity (GsT) is approximately zero. However, if overall genetic variation exceeds subpopulational variation, the GST is greater than zero (Hart1 & Clark, 1989). In this case, the assortment of samples into subpopulations for the purpose of the analysis may approximate the natural division of the population into subunits. An estimate of the significance of the GSTis obtained by randomly assigning samples to subpopulations, which are the same size as those used in the calculation of the index, and recalculating the GsT. This process of bootstrapping was repeated 1000 times for each index of diversity. The index of gene diversity is judged to be significant if it exceeds all of the bootstrapped estimates (Palumbi & Wilson, 1990).

Stock Identity of the Red and Green Rock Lobsters

31 1

Two possible population structures were tested for the red rock lobster. The first assumed that populations would be related if their larvae shared the same current systems, either offshore currents or inshore eddy systems. The second model assumed that populations would be related if they shared the same environmental parameters. A full description of the population models, and the groupings of samples for each model, can be found in Ovenden et af. (1991). For the green rock lobster, the Tasman Sea was assumed to be a likely barrier to gene flow. Consequently, for the purposes of gene diversity analyses, the lobsters sampled from the two New Zealand locations were grouped and tested against the Australian samples. In most animal populations, especially those which are subdivided into smaller units, there will be a positive correlation between geographical proximity and genetic relatedness between pairs of individuals. In this study of mtDNA variation in lobsters, a certain number of haplotypes, or lobster mitochondrial genomes, was identified. The approximate genetic relationship between pairs of these haplotypes can be determined by estimating their degree of nucleotide similarity (or nucleotide sequence divergence; Nei & Tajima, 1983). The resulting matrix of similarity values can be converted into a diagram of relatedness (tree) using a phenetic phylogenetic technique called the unweighted pair-group method with arithmetic means (UPGMA; Nei, 1987, p. 293). This does not result in a definitive description of haplotype relationships, and there are many alternative phylogenetic techniques which could also be used (Nei, 1987). If the haplotypes on the same branch of the relatedness tree are identified from lobsters collected from the same general, or specific, geographical location then it may be possible to infer that certain barriers to dispersal or random mating exist within the population.

16.3.3

Results

In total, 55 different mitochondrial haplotypes were identified among the 132 red rock lobsters sampled and 10 among the 20 green rock lobsters. The distribution of haplotypes across the collection locations in Australia and New Zealand is detailed in Table 16.1. As initially reported by Brasher et a f . (1992b), the number of haplotypes found amongst the lobsters included in this study confirms that, unlike the allozyme nuclear gene loci in this genus, the mitochondrial genome provides a variable genetic system with which to analyse stock structure. The amount of mtDNA variation found among lobsters from the same collection location appeared to be smaller for J . verreauxi (nucleotide sequence diversity was 0.24 for North Cape, New Zealand, ranging to 0.46 for Era Beach, New South Wales) than for J . edwardsii (nucleotide sequence diversity was 0.44 for Gisborne, New Zealand ranging to 0.96 for Port Fairy, Victoria; Table 16.2). The assortment of red rock lobster samples among variously defined subpopulations did not yield significantly large indices of genetic diversity. The GsT values

312 Spiny Lobsters: Fisheries and Culture Table 16.1 Mitochondria1 haplotypes of Jarus edwardsii and 3. verreawi specimens and their collection locations. Haplotypes are a compilation of letters, each of which signifies an O h N e d restriction site pattern for a particular restriction enzyme (restriction enzyme order: Afll, Avd. Bml, BsfYI. EcoRV and Hindlll). The number of individuals possessingeach haplotype i s indicated in parentheses Location

Sample size

Haplotypes

Jarus cdwardsii Western Australia Esperance

34'00's 122'00'E

15

South Australia Bucks Bay

A A A A A A (31, AAABAB (2). AAACAB (3), AAAEAA (l), AAAFAB (1). AAAMAB (I), AACAAA (1). AADAAA (1). ADABAH (1). CBANAN (1)

3F53'S 1 W 3 ' E

8

34-46's 135'52'E

10

Victoria Port Fairy

A A A A A A ( I ) , AAAAAJ (1). AAALAB (1). AAGKAA (1). AAJAAA (I), BBAJJA (I), H A A A A A (I). IAABAB (1) AAAAAA (2). AAABAA (1). AADAAA (I). AADCAG (1). AAEAAA (1). AAGAAA (I), ABAFAB (1). CAABAB (l), IAABAB (I),

3853's 142"18'E

10

Bas Strait King Island

A A A A A M (1). AAACAB (1). AAAEAA (l), AAAIAB (11, AADAAA (1). AAGAAA ( I ) , AAHCAB (1). ABAFAB (2), ABABAD (1)

39'52's 143'49'E

10

WOO'S 148"16'E

10

AAAAAA (1). AAABAB (l), AAABAL (l), AAACAB (1)- AAADAB (I), AAAMAB (1) AADAAA (1). AAFAAA (1). AAGAAA (1). CAACAB (1) A A A A A A (1). AAABAB (1). AAACAB (2) AAAEAA ( I ) , AACAAA (I), AADDAB (1) AAEAAA (I), ADAAAA ( I ) , BAFAAA (1)

41"14'S 144"35'E

I1

AAAAAA (2). AAAADA ( I ) , AAACAB (1). AAAEAA ( I ) , AADAAA (1). BAAAAA (1). BAABAB (1). CAADAB (1). DAAHBA (I), FCABEB (1)

Flying Cloud Point

43"31'S 145'55'E

16

Sullivans Point

43"33'S 146O55'E

13

Bicheno

41"57'S 148"19'E

6

A A A A A A (4). AAAACB (l), AAABAB (3). AAABAF (I), AAAEAG (1). AAAFAB (1). AAAIAB (1). AADAAE (I), AAGGAA (1). ADABAD (I), EBAFAC (1) A A A A A A (2). AAACAB (1). AAAIAB (Z), AABAAA (1). AACAAA (l), AAEAAA (1). ABAFAB (3). CAABAB (l), GCABAB (I), AAABAA (I), AAACAB (l), AADAAA (1). ADABAD (l), ADABAH (l), JEABAB (1)

35'45'5 15050'E

4

New Zealand Gisborne

3F37'S 17WO'E

10

Moeraki

4591'5 17W54'E

9

Jasus verreawi Australia Era Beach

34-11's 151WE

6

New Zealand North Cape Matakaoa Point

AAAAAA (Z), AAAABA (2). AAABBA (1). BAACAB ( I )

3426'5 173W'E 3734's 17850'E

5 9

AAAAAA (1). ABAAAA (I), AAAAAC (3) AAAAAA (4), ACAAAA (l).BAAAAA ( l ) , AAAAAC (1). CAAAAC (1). AACAAC (1)

Port Lincoln

Flinders Island Tasmania Temma

New South Wales Batemans Bay

AAAAAA (I), AAKCAB (1). AFABAB (1). IAABAB (1) AAAAAA (3). AAACAB (3). AADAAA (2). AAFAAA (1). AAFGAA (1) A A A A A A (3), AAAAAE (1). AAABAB (1). AAACAB (I), AAGAAK (I), CAACAB (l), EAABAB (1)

varied from 0.168 (current flow, grouping 1) to 0.238 (environmental, grouping 3). All of the GST values calculated for various groupings of red rock lobsters samples fell within the range of 1000 estimates from randomized data, although the index of gene diversity for one of the groupings (environmental, grouping 1; GST = 0.190) exceeded 92.2% of the randomized values. In this grouping, the sampled lobsters were divided into three groups: western Tasmania to western Australia, eastern

Stock Identity of the Red and Green Rock Lobsters

313

Table 16.2 Intrapopulational mean mtDNA nucleotide sequence diversity and standard errors (YO) for fifteen populations of the red (Jusus edwardsii) and green ( J . verreuuxi) rock lobster Collection location Jams edwardsii King Island, Bass Strait Flying Cloud Point, Tasmania Temma, Tasmania Sullivans Point, Tasmania Flinders Island, Bass Strait Port Lincoln, South Australia Gisborne, New Zealand Moeraki, New Zealand Bucks Bay, South Australia Bicheno, Tasmania Port Fairy, Victoria Batemans Bay, New South Wales Esperance, Western Australia Jams verreauxi North Cape, New Zealand Matakaoa Point, New Zealand Era Beach, New South Wales

Diversity

Standard error

0.69 0.78 0.89 0.92 0.77 0.73 0.44 0.71 0.85 0.86 0.96 0.88 0.77

0.25 0.24 0.25 0.26 0.25 0.24 0.24 0.26 0.22 0.27 0.25 0.33 0.25

0.24 0.33 0.46

0.19 0.17 0.23

Australia and New Zealand. In general, however, gene diversity analyses of the mitochondria1 haplotypes of the red rock lobster were unable to reject the hypothesis of overall genetic homogeneity of possible stocks. The indices of diversity for the green rock lobster populations suggest that the species may not be genetically homogeneous between Australia and New Zealand. When the lobster haplotypes from the two New Zealand samples (North Cape and Matakaoa Point) were grouped together and compared with the haplotypes from the Australian population (Era Beach) the GST value was 0.294. This value was greater than 99.3% of 1000 GST values calculated from random rearrangements of the same data set. Similarly, the GST value was 0.345 when each collection location of green rock lobsters was taken to indicate a separate subpopulation. The phenetic clustering analysis supports the results of the gene diversity analysis for the green rock lobster. The 10 green rock lobster haplotypes were shown to form three clusters of two, three and four haplotypes each, with one haplotype forming a branch alone (Fig. 16.3). The largest cluster contained the most common green rock lobster haplotype, AAAAAA, which was found twice in the Australian sample and five times in the two New Zealand samples. The remaining three haplotypes from that cluster were from lobsters sampled only in New Zealand waters. The cluster of

3 14 Spiny Lobsters: Fisheries and Culture n a

I

0.5

I

0.1 0 Nucleotide Sequence Divergence (%) 0.4

0.3

0.2

Fig. 16.3 Association between mitochondrial DNA haplotype similarity and geographical proximity for green rock lobsters (Jusus vevreuuxi) from New Zealand (n; Matakaoa Point and North Cape) and Australia (a; Era Beach). Each dot indicates the geographical occurrence of a particular lobster mitochondrial genome. The horizontal bars to the left of the dots show the hierarchical genetic relationship between genomes, according to nucleotide sequence divergence.

three haplotypes represented six lobsters also from New Zealand, and the cluster of two haplotypes represented three Australian lobsters. The haplotypes in these two clusters were further identified by the possession of restriction sites which were unique to either Australia or New Zeland lobsters. The occurrence of similar haplotypes on the same side of the Tasman Sea, in either Australia or New Zealand, and especially the possession by some of the samples of unique restriction sites, suggests that the green rock lobster may not be genetically continuous between the two countries. The phenetic clustering analysis of the red rock lobster samples did not show any association between the genetic similarity of the haplotypes and their geographical distribution. There were no clusters of haplotypes confined to any particular geographical region (Fig. 16.4).

16.3.4

Discussion

This analysis of the mitochondrial genome of red rock lobsters failed to detect any pattern in nucleotide sequence variation which could be linked to their geographical location. The lack of an underlying pattern to explain genetic variation does not provide evidence for extensive gene exchange within the species. As previously explained, mtDNA analysis provides only a one-way test for the possibility of restricted gene flow within a species. Consequently, despite the observed homogeneity in mtDNA sequence variation, mechanisms may be operating within

Stock Identity of the Red and Green Rock Lobsters

315

bc n r t w

n;

Jasus edwardsii

I 0.8

I

I

I

0.6

0.4

0.2

I

0

NucleoNde Sequence Divergence (%)

Fig. 16.4 Association between mitochondrial DNA haplotype similarity and geographical proximity for red rock lobsters (Jams edwardsii) from Bass Strait (b; Bucks Bay, South Australia; Port Fairy, Victoria; King and Flinders Island; Temma and Bicheno, Tasmania), eastern Australia (e; Batemans Bay, New South Wales), New Zealand (n; Gisborne and Moeraki), South Australia (s; Port Lincoln), southern Tasmania (t; Flying Cloud Point and Sullivans Point) and Western Australia (w; Esperance). Each dot indicates the geographical occurrence of a particular lobster mitochondrial genome. The horizontal bars to the left of the dots show the hierarchical genetic relationship between genomes, according to nucleotide sequence divergence.

3 16 Spiny Lobsters: Fisheries and Culture

the species which have caused, and continue to maintain, complete or partial barriers to larval exchange between geographical localities. For example, small-scale and presently undetected inshore eddy systems or the vertical movements of phyllosomas through currents flowing in different directions or at different speeds (Phillips & McWilliam, 1986) may ensure that the majority of phyllosomas is returned to the parental environment. In addition, Pollock (1990) has proposed that phyllosomas may have the ability to recognize and selectively settle in their 'home' environment, possibly by recognizing minute changes in water composition or temperature. If one or more of these mechanisms is operating within the red rock lobster, the resulting genetic patterns caused by restrictions to gene flow may be detectable in a more detailed and extensive analysis of their mitochondrial genomes. Alternatively, if red rock lobster larvae are freely exchanged between locations, as their widespread and prolonged survival suggests, it is most likely that they are dispersed from west to east in the prevailing west wind drift. If future studies are able to confirm this one-way movement, then westerly populations may deserve special conservation status. A similar study of the mitochondrial genomes of Punulirus argus from five locales in the Carribean was also unable to provide evidence for potential restrictions to gene flow (Silberman et al., 1994). In contrast to the data collected from the red rock lobster, the results of the mtDNA analysis of the green rock lobster provide preliminary evidence for restrictions to gene flow between New Zealand and Australian populations. Confirmation of these results will depend on a more extensive mtDNA analysis, which should include specimens from more widespread sampling. Assuming that the results from this analysis are taken at face value, there is an interesting paradox in the presence of genetic continuity between Australian and New Zealand red, but not green, rock lobsters across the Tasman Sea. The slightly more northerly distribution of the green rock lobster, in conjunction with complex circulation patterns within the Tasman Sea, may provide an explanation. The transTasman flow of water, which is most likely to disperse Australian green rock lobster larvae, leaves the Australian coast at approximately 34"s and moves in a northeasterly direction, departing the Tasman Sea well north of New Zealand (Hamilton, 1990). Consequently, any larvae within this flow will enter the Pacific Ocean and fail to contribute to Australian or New Zealand stocks. Waters south of this northeasterly flow, which contain larvae of the more southerly red rock lobster (Booth et al., 1990), move from the Australian coast and impinge upon the east coast of northern New Zealand (Heath, 1980), thus facilitating gene flow across the Tasman Sea. Strict genetic separation of planktonic animals by oceanic currents is not without precedent. Bucklin et al. (1989) found that the genetics of a planktonic calanoid copeopod, Metridia pacifica, differed significantly between coastal and offshore water flows off the northern California coast. The existence of an isolated, self-sustaining population of green rock lobsters in New Zealand is supported by tagging studies (Booth, 1984, 1986), which show that juveniles move from the east coast of the North Island to Cape Reinga, the major

Stock Identity of the Red and Green Rock Lobsters

311

Table 16.3 Indices of gene diversity (GsT)between putative subpopulations of the red (Jasus edwardsii)and green (Jasus verreauxi) rock lobsters. Jams edwardsii population groupings are described in Table 2 of Ovenden et al. (1990)

Grouping type

GsT

Rangea

Significanceb

Jams edwardsii Current flow 1 2

0.168 0.188

0.138-0.232 0.1640.246

12.3% 19.5%

0.190 0.193 0.238

0.127-0.222 0.135-0.250 0.212-0.279

92.2% 63.8% 26.9%

0.294 0.345

0.183-0.323 0.207-0.360

99.3% 99.0%

Environmental 1 2 3 Jams verreauxi Australian v. New Zealand All collection locations as separate subpopulations

aRange of 1000 G S T values calculated by randomly rearranging the data amongst subgopulations. Percentage of bootstrapped estimates which are exceeded by the GSTvalue. breeding area located at the extreme north of the North Island. This movement, which is against the prevailing current, appears to ensure larval recruitment back to the east coast and prevents larval wastage to the east and south of New Zealand. Australian populations of the green rock lobster are presumably sustained by recruitment of larvae from local, inshore eddy systems which have escaped northeasterly, trans-Tasman movement.

16.3.5

Future genetic research

An important task for the future is to confirm the unexpected break in the mitochondria1 genetics of green rock lobsters across the Tasman Sea. Although this species is not a large commercial resource, it shares features of larval and adult biology with other commercially valuable species, both in Australia ( J . edwardsii and P . cygnus) and world-wide (J. lalandii and P . argus). Consequently, further information about restrictions to gene flow in the green rock lobster could provide important hypotheses about general lobster dispersal and recruitment. Instances of restrictions to gene flow in marine species with planktonic larvae are rare, and thus a further study of the genetics of the green rock lobster in Australia and New Zealand may have important ramifications for the field of marine population biology. The most important aspect of an expanded study of the green rock lobster would be to increase the number of specimens collected and the number of sampling localities. It

318 Spiny Lobsters: Fisheries and Culture

may not be necessary to increase the resolution of the genetic analysis by using a more extensive array of restriction enzymes or by using a more advanced analysis technique, as the high level of mtDNA sequence variation in members of this genus ensures adequate results with a relatively small number of restriction enzymes. The overall magnitude of mtDNA sequence variation in the red and green rock lobsters, and its consistency between geographical locales, provide a stable baseline against which to measure possible future reductions in genetic diversity. A comparative reduction in mtDNA variation would indicate the prior occurrence of a bottleneck event. Such events may be induced by a severe reduction in population size due to factors such as excess fishing pressure or widespread disease. The occurrence of a bottleneck may be taken as evidence of a lack of significant gene flow into the affected population from other areas. The high level of mtDNA sequence variation found in Jasus species (Brasher et al., 1992b) provided the resolution required to confirm the proposed synomomy of the two nominal species of red rock lobsters, J . novaehollandiae (southern and southeastern Australia) and J. edwardsii (New Zealand: Booth et al., 1990). Recently, mtDNA analysis was used to test the specific status of two morphologically cryptic Jams species, J. tristani (Tristan da Cunha, Gough Island and Vema Seamount) and J . paulensis (St. Paul and New Amsterdam Islands). Ovenden et al. (1997) showed that J . tristani and J . paulensis are so genetically similar that further genetic, morphological and behavioural analyses are needed to assess their status as separate species.

Acknowledgements This research has been greatly assisted by the co-operation of colleagues from the fishing industry, government departments and universities both in Australia and overseas. They have been named and thanked in previous publications. This work was funded by the Australian Fishing Industry Development Corporation and the University of Tasmania.

References Avise, J.C. (1989) Gene trees and organismal histories: a phylogenetic approach to population biology. Evolution, 43, 1192-208. Avise, J.C. & Saunders, N.C. (1984) Hybridization and introgression among species of sunfish (Lepomis): analysis by mitochondria1 DNA and allozyme markers. Genetics, 108, 237-55. Booth, J.D. (1984) Movements of the packhorse rock lobsters (Jams verreauxi) tagged along the eastern coast of North Island, New Zealand. N.Z. J. Mar. Freshwat. Res., 18, 275-81. Booth, J.D. (1986) Recruitment of packhorse rock lobster Jasus verreauxi in New Zealand. Can. J . Fish. Aquat. Sci., 43, 2212-20. Booth, J.D., Street, R.J.& Smith, P.J. (1990) Systematic status of the rock lobsters Jams edwardsii from New Zealand and J. novaehollandiae from Australia. N.Z. J. Mar. Freshwaf. Res., 24, 23949.

Stock Identity of the Red and Green Rock Lobsters

319

Brasher, D.J. (1992) Methods for restriction enzyme analysis of mitochondrial DNA from adult and puerulus rock lobster, Jasus edwardsii (Crustacea: Decapoda: Palinuridae) M.Sc. Qual. Thesis, University of Tasmania, Tasmania. Brasher, D.J., Ovenden, J.R., Booth, J.D. & White, R.W.G. (1992a) Genetic subdivision of Australian and New Zealand populations of Jams verreauxi (Decapoda: Palinuridae). Preliminary evidence from the mitochondrial genome. N . Z . J . Mar. Freshwat. Res., 26, 53-8. Brasher, D.J., Ovenden, J.R. & White, R.W.G. (1992b) Mitochondrial DNA variation and phylogenetic relationships of Jasus spp. (Decapoda: Palinuridae). J. Zool. (Lond.), 227, 1- 16. Brown, W.M. (1985) The mitochondrial genome of animals. In Molecular Evolutionary Generics (Ed. by R.J. MacIntyre), pp. 95-130. Plenum, New York, USA. Brown, W.M., George, M. & Wilson, A.C. (1979) Rapid evolution of animal mitochondrial DNA. Proc. Nut1 Acad. Sci. U.S.A., 76, 1967-71. Bucklin, A., Rienecker, M.M. & Mooers, C.N.K. (1989) Genetic tracers of zooplankton transport in coastal filaments off Northern California. J. Geophys. Res., 94(C6), 8277-88. Chapman, R.W. & Powers, D.A. (1984) A method for the rapid isolation of mitochondrial DNA from fishes. Maryland Sea Grant Program Technical Report UM-SG-TS-84-05. Forbes, S.H., & Allendorf, F.W. (1991) Mitochondrial genotypes have no detectable effects on meristic traits in cutthroat trout hybrid swarms. Evolution, 45, 1350-9. George, R.W. (1966) Marine crayfish or spiny lobsters of Australia. Aust. Fish. Newslett., 25, 25-8. Gyllensten, U. & Wilson, A.C. (1987) Mitochondrial DNA of salmonids: inter- and intraspecific variability detected with restriction enzymes. In Population Genetics and Fisheries Management (Ed. by N. Ryman & F. Utter), pp. 301-18. Seattle, WA, USA. Hamilton, L.J. (1990) Temperature inversions at intermediate depths in the Antarctic Intermediate Waters of the south-western Pacific. Aust. .IMar. . Freshwat. Res., 27, 251-62. Hartl, D.L. & Clark, A.G. (1989) Principles of Population Genetics. Sinauer, Sunderland, MA, USA. Heath, R.A. (1980) Eastwards oceanic flow past northern New Zealand. N . Z . J. Mar. Freshwat. Res., 14, 169-82. Hillis, D.M, Moritz, C. & Mable, B.K. (1996) Molecular Systematics. Sinauer, Sunderland, MA, USA. Holthuis, L.B. (1963) Preliminary descriptions of some new species of Paninuridea (Crustacea, Decapoda, Macrura, Reptantia). Proc. K . Ned. Akad. Wet. (Sect. C ) , 66, 54-60. Johnson, M.W. (1971) The palinurid and scyllarid lobster larvae of the tropical eastern Pacific and their distribution as related to the prevailing hydrography. Bull. Scrips inst. Oceunogr. Univ. C a l g , 19, 1-36. Kensler, C.B. (1967) The distribution of spiny lobsters in New Zealand waters (Crustracea: Decapoda: Palinuridae). N . Z . J . Mar. Freshwat. Res., 1, 412-20. Lande, R. (1998) Anthropogenic, ecological and genetic factors in extinction and conservation. Res. POPUI.Eco~.,40, 259-69. Moritz, C., Dowling, T.E. & Brown, W.M. (1987) Evolution of animal mitochondrial DNA: relevance for population biology and systematics. Ann. Rev. Ecol. Syst., 18, 269-92. Mulley, J.C. & Latter, B.D.H. (1980) Genetic variation and evolutionary relationships within a group of thirteen species of penaeid prawns. Evolution, 34, 904-16. Nei, M. (1987). Molecular Evolutionary Genetics. Columbia University Press, New York, USA. Nei, M. & Tajima, F. (1983). Maximum likelihood estimation of the number of nucleotide substitutions from restriction sites data. Genetics, Austin, Tex., 105, 207-1 7. O’Connell, M. &Wright, J.M. (1997) Microsatellite DNA in fishes. Rev. Fish Biol. Fisheries, 7, 33163. Ovenden, J.R. (1990) Mitochondrial DNA and marine stock assessment: a review. Aust. J . Mar. Freshw. Res., 41, 835-53.

320 Spiny Lobsters: Fisheries and Culture Ovenden, J.R., Booth, J.D. & Smolenski, A.J. (1997) Mitochondrial DNA phylogeny of red and green rock lobsters (genus Jasus). Mar. Freshwat. Res., 48, 1131-36. Ovenden, J.R., Brasher, D.J. &White, R.W.G. (1991) Mitochondrial DNA analysis of the red rock lobster (Jasus edwardsii) supports an apparent absence of population subdivision throughout Australasia. Mar. B i d , 112, 319-26. Ovenden, J.R., Bywater, R. & White, R.W.G. (1992) A program for the estimation of restriction endonuclease site positions from restriction fragment size and number an aid for mitochondrial DNA analysis. J. Hered., 83, 24&41. Palumbi, S.R. & Wilson, A.C. (1990) Mitochondrial DNA diversity in the sea urchins. Evolution, 44,403-15. Phillips, B.F & McWilliam, P.S. (1986) The pelagic phase of spiny lobster development. Can. J. Fish. Aquat. Sci., 43, 2153-63. Pollock, D.E. (1990) Palaeoceanography and speciation in the spiny lobster genus Jasus. Bull. Mar. Sci., 46, 387405. Richardson, B.J., Baverstock, P.R. & Adams, M.A. (1986) Allozyme Electrophoresis. A Handbook for Animal Systematics and Population Studies. Academic Press, Sydney, Australia. Seeb, L.W., Seeb, J.E & Polovina, J.J. (1990) Genetic variation in highly exploited spiny lobster Panulirus marginatus populations from the Hawaiian Archipelago. Fish. Bull., 88, 713-18. Shaklee, J.B. & Samollow, P.B. (1984) Genetic variation and population structure in a spiny lobster, Panulirus marginutus, in the Hawaiian Archipelago. Fish. Bull., 82, 693-702. Silberman, J.D., Sarver, S.K. & Walsh, P.J. (1994) Mitochondrial DNA variation and population structure in the spiny lobster Panulirus argus. Mar. Biol., 120, 601-8. Smith, P.J., McKoy, J.L. & Machin, P.J. (1980) Genetic variation in the rock lobsters Jasus edwardsii and Jasus novaehollandiae. N.Z. J. Mar. Freshwat. Res., 14, 5543. Stevens, P.M. (1990) A genetic analysis of the pea crabs (Decapoda: Pinnotheridae) of New Zealand. I. Patterns of spatial and host-associated genetic structuring in Pinnotheres novaezeiandiae Filhol. J. Exp. Mar. Biol. Ecol., 141, 195-212. Tegelstrom, H. (1987) Transfer of mitochondrial DNA from the northern red-backed vole (Clethrionomys rutilis) to the bank vole ( C . glareolus). J . Mol. Evol., 24, 218-27. Tracey, M.L., Nelson, K., Hedgecock, D., Shleser, R.A. & Pressick, M.L. (1975) Biochemical genetics of lobsters: genetic variation and the structure of American lobster (Homarus americanus) populations. J . Fish. Res. Board Can., 32, 2091-101. Ward, R.D. & Grewe, P.M. (1994) Appraisal of molecular genetic techniques in fisheries. Rev. Fish Biol. Fisheries, 4, 300-25. ~

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 17

Spiny Lobster Catches and the Ocean Environment B.F. PHILLIPS

Curtin University of Technology, P . 0 . Box U1987, Perth, Western

Australia 6845, Australia

A.F. PEARCE

CSIRO Division of Marine Research, P.O. Box 20, North Beuch, Western

Australia 6020. Australia

R. LITCHFIELD SIR Pty Ltd, Sydney, Australia

s. G U Z M h DEL P R O 0

Instituto Polite'cnico Nacional, Escuela Nacional de Ciencius

Bioldgicas. Luboratorio de Ecologia Marine', Ap. Postal 26-375 02860, Mixico DF

17.1

Introduction

The western rock (spiny) lobster (Panulivus cygnus) fishery is one of the world's largest lobster fisheries, averaging over 10 500 t per year. Most of the catch is taken between latitudes 28 and 32"S, although the fishery ranges from 22 to 34"s along the coast of Western Australia (Phillips & Brown, 1989). The annual value of the catch is about Aus $250 million, making it the most lucrative single-species fishery in Australia. The fishery has been carefully, with both the Commonwealth and Western Australian State governments, committed to research into the life history of the lobster (Phillips, 1989). Much of the larval life of the lobster is spent in the open ocean where the larvae (phyllosoma) become widely distributed (Phillips, 1981). Larval recruitment depends on the successful return of sufficient phyllosoma to coastal waters. How they return can only be postulated, but about 9 months after hatching there are large numbers of final stage phyllosoma off the continental shelf of Western Australia (Pearce & Phillips, 1994). The final-stage phyllosoma metamorphoses into a puerulus stage somewhere near the shelf break, although neither the precise location nor the stimulus is known. The free-swimming puerulus stage completes the pelagic cycle and on settlement in the coastal reefs provides the basis for subsequent recruitment to the fishery. The puerulus moults into the juvenile stage, which remains in the nursery reefs for 3-5 years before migrating offshore into deeper water. Recruitment is defined as the entry of these legally sized animals (76 mm carapace length) animals into the fishery. In considering the relationships between the ocean environment and the catches of the fishery for P. cygnus there are two distinct aspects of interest: the factors responsible for variations in the level of puerulus settlement at the end of the oceanic phase, and the link between settlement of the puerulus and recruitment to the fishery. 32 1

322 Spiny Lobsters: Fisheries and Culture

Studies have shown a high correlation between the levels of settlement of the puerulus stage of the western rock (spiny) lobster and interannual variability in the flow of the Leeuwin Current, the anomalous poleward boundary current in the south-eastern Indian Ocean (see Fig. 17.1, modified from Pearce & Phillips, 1988). The strength of the Current is inferred from the coastal sea level at Fremantle which, in turn, is closely related to the southern oscillation index (SOI) and hence to El Niiio Southern Oscillation (ENSO) events. Other studies have shown a high correlation

H"

SEA LEVEL

68 70 72 74 76 78 80 82 84 86 88 90 92 94 96

Fig. 17.1 Annual mean data for the southern oscillation index, Fremantle sea level, the index of puerulus settlement at Seven Mile Beach, Dongara and annual catches of the western rock lobster Panulirus cygnus in Western Australia.

Spiny Lobster Catches and the Ocean Environment

323

between the levels of puerulus settlement and subsequent recruitment to the fishery, and the level of puerulus settlement can be used to predict future catches 4 years in advance (Phillips, 1986; Caputi et al., 1988). These data are summarized in Fig. 17.1. Pearce & Phillips (1988), Phillips and Pearce (1991) and Phillips et al. (1991) interpret this as fluctuations in the strength of the Leeuwin Current in phase with the southern oscillation. During ‘normal’ (or non-ENSO) years, coastal sea level is relatively high and the Leeuwin Current is correspondingly strong; the settlement index is also relatively high. Hydrographic measurements on the continental shelf off Perth confirm that there is warmer, less saline water along the outer shelf during these periods. In contrast, during ENS0 years sea level is lower, the Leeuwin Current is weaker and settlement is low. Phillips & Pearce (1991) showed a correlation between sea level and the total annual catch of P . cygnus 4 years later, indicating that in the absence of data on the levels of puerulus settlement, it might be possible to use other information such as sea level or SO1 to perform a similar, if perhaps less accurate, prediction function. Phillips et al. (199 1) showed that similar processes affect larval recruitment along the whole coast in the area of the fishery. In summary, the level of recruitment to the western rock lobster fishery in any year is related to levels of puerulus settlement, which in turn are linked with oceanographic processes operating towards the end of the oceanic migration of the larval and puerulus stages. The mechanisms involved are unknown, but with time, more extensive biological and environmental datasets will become available, which (with satellite imagery) should enable researchers to focus on the dominant physical processes involved. However, the critical point is that about half of the variation in puerulus settlement has been explained by environmental factors and these variations in the levels of puerulus settlement are subsequently reflected in the catch. This chapter examines environmental factors including SOI, sea level and sea surface temperature (SST), and annual data on spiny lobster catches from Western Australia, Baja Mexico, Brazil, Japan, Cuba and New Zealand, to determine the extent to which ocean environment affects catches in these spiny lobster fisheries. These were selected because of the long-term records that were available for lobster catches in these countries. The Western Australian fishery is included because some additional analyses have been undertaken against which the other regions can be assessed.

17.2

Data

Catch data for the lobster fisheries were obtained from several sources and do not necessarily coincide with the data published by FAO. The data on P . cygnus were obtained from the Western Australian Fisheries Department, courtesy of R. Brown and the Commercial Fisheries Production Bulletins of Fisheries Western Australia;

324 Spiny Lobsters: Fisheries and Culture Panulirus argus in Cuba from the Centro de Investigaciones Pesqueras, Cuba, courtesy of Dr R. Cruz; P . argus and P . laevicauda in Brazil from Dr A.A. Fonteles Filho, of Mar Universidade do Ceara; Jasus edwardsii in New Zealand from Breen (1988) and also courtesy of Dr J. Booth of MAFFISH, New Zealand; and Panulirus japonicus from the F A 0 Yearbooks of Fishery Statistics, up to Vol. 66. The environmental data used in these analyses have been obtained from a variety of sources of differing (and sometimes unknown) reliability. It has not always been possible to match the specific environmental dataset with the fishery. For example, long-term reliable sea-level information is available only from sites some hundreds of kilometres from the centre of the fishery. However, this should not be a major problem where examining interannual data with the implied large-scale variability. The SO1 was used as an index of global ocean-atmosphere variability, as the southern oscillation is associated with interannual climate fluctuations around the globe. Although the index itself (which is a measure of atmospheric pressure changes between the Indian and Pacific Oceans) is unlikely to influence directly any of the fisheries, other local oceanic or meteorological changes are likely to be linked in some way with the SOL It is therefore the one physical quantity that can be expected to be relevant to all fishery sites analysed here. Annual values of the SO1 were computed from monthly means listed in the Darwin Tropical Diagnostic Statement (Bureau of Meteorology, Australia). Whereas it is difficult to visualize a direct physical link between the SO1 and catches in a fishery, coastal sea levels can be used as an indicator of oceanic processes acting along the continental shelf and may therefore be expected to have an important influence on catch. Pearce & Phillips (1988) and Pattiaratchi & Buchan (1991), for example, have interpreted changes in monthly and annual mean sea levels off Western Australia as fluctuations in the Leeuwin Current, and Pearce & Phillips (1988) have shown that annual settlement of the western rock lobster is associated with such variations in sea level. Pearce & Phillips (1988) have also shown that interannual variations in coastal sealevel along the Western Australian coast are highly correlated with the SOI, implying that variations in the strength of the Leeuwin Current are linked with events in the Pacific Ocean. Sea-level data for Fremantle were supplied by the National Tidal Facility, The Flinders University of South Australia (Copyright reserved), while those for the New Zealand sites were kindly provided by Dr J. Hannah of the Department of Survey and Land Information (discussed in Hannah, 1990). Sea-level data for Ensenada (Mexico), Japan and Brazil were extracted from tapes supplied by the Permanent Service for Mean Sea Level (PSMSL), using the adjusted Revised Local Reference (RLR) dataset. Like sea level, SST may be considered an indicator of oceanic processes relevant to local recruitment to a fishery. SST changes linked with the Leeuwin Current are associated with interannual variations in larval recruitment to the western rock lobster fishery (Pearce & Phillips, 1988). SST data for Western Australia were obtained from the CSIRO coastal station off Rottnest Island (20 km west of

Spiny Lobster Catches and the Ocean Environment

325

Fremantle) (Pearce & Phillips, 1988). For this area as well as the other sites, SST data were also extracted from the Comprehensive Ocean-Atmosphere Data Set (COADS) on the World WeatherDisc (WeatherDisc Associates, 1990). The locations of the lobster fisheries and the sites at which the sea-level data were obtained are shown in Fig. 17.2. The areas for the COADS SST data were selected as appropriate for each fishery.

17.3

Results

Graphs of catches from the six sites (Western Australia, New Zealand, Cuba, Japan, Brazil and Baja Mexico) indicated strong linear trends in the Mexican, Cuban and New Zealand catch data, a weaker linear trend in the Brazil and Western Australian catch data, and non-linear trends in the Japanese catch data (Fig. 17.3a-f). Polynomial trends were removed from all catch data; these were mostly linear trends, although the Japanese trend was quartic. Autocorrelations of the environmental and catch series were calculated. The autocorrelations of the environmental series were mostly low, but there were some significant autocorrelation patterns for most catch series (after the trends had been removed). As expected, most of these significant autocorrelations occur with a 1-year lag, i.e. a high catch one year is likely to be followed by a high catch the next year,

30a

N

0 0

30' S

Fig. 17.2 Map showing the location of the spiny lobster fisheries and the sites (triangles) at which sea-level data were obtained.

326 Spiny Lobsters: Fisheries and Culture WESTERN AUSTRALIA 8000

8000

1

lOOO]

1 0 1050

1060

1070

1080

1000

Years

Fig. 17.3 Time-series of annual spiny lobster catches: (a) Panulirus cygnus in Western Australia; (b) Jasus edwardsii in New Zealand; (c) Panulirus argus in Cuba; (d) Panulirus juponicus in Japan; (e) P. argus and Panulirus laevicauda in Brazil; (f) Panulirus interruptus in Baja, Mexico.

suggesting that high recruitment levels tend to benefit the fishery over a couple of years rather than a single year. Cross-correlations were calculated between the environmental series (SOI, sea level and SST) and the lagged detrended catch series. The test statistics for crosscorrelations are only valid if each of the series has a zero autocorrelation function. Therefore, there are few valid tests. Diggle (1990) suggests the approximate formula [2/,/nl, where n is the total number of years, to assess the significance of the crosscorrelation function if the calculated value exceeds I2/Jnl. In the present study, n was modified to n*, the effective number of years, using the Bayley & Hammersley (1946) method. The conservative significance levels indicated in Table 17.1 were calculated by this technique. Comment is made mainly on the maximum correlation and the correlation patterns in each case because the correlation pattern is more informative than single correlations and their significance.

17.3.1

Southern oscillation index and catch

There was a negative correlation between SO1 and the Cuban catch of P . argus 2 years later (Fig. 17.4). There were also correlations between SO1 and the Western

Spiny Lobster Catches and the Ocean Environment 0.5

o.4[: CUBA

321

SO1 with catch

0.3 0.2 0.1 -

-

-0.6) 0

I

1

I

I

I

I

I

I

I

I

1

I

2 3 4 5 6 7 8 9 1 0 1 1 1 2 Lag in years

Fig. 17.4 Correlations between the southern oscillation index and catches of the spiny lobster Panulirus argus in Cuba.

Table 17.1 Maximum cross-correlations of environmental variables with catch and significance levels using the Bayley & Hammersley (1946) method Location

Series

Western Australia

so1 SST Sea level

Brazil

Cuba

Mexico (Baja)

so1

30 23 23

No data

SST Sea level

22 22 22

so1

so1

so1

SST Sea level New Zealand

30 21

SST Sea level

SST Sea level Japan

n (Years)

so1

SST Sea level

56 42

2/Jn*

Maximum correlation

0.527 0.615

0.466 -0.632

0.527 0.550

0.495 0.397

0.550

-0.333

0.510

-0.506 0.242 0.374 0.223

0.510 0.510 0.400

0.450

-0.333 0.341

32 36 36

0.510 0.530 0.530

36

0.530 0.660

0.294 -0.326

0.660

0.3 12

36 No data 36

SOI, southern oscillation index; SST, sea surface temperature.

0.324 0.291

(Lag, years)

328 Spiny Lobsters: Fisheries and Culture Australian catch of P . cygnus 3 years later and between SO1 and the Brazil catch of P . argus and P . laevicauda 4 years later (Table 17.1).

17.3.2

Sea levels and catch

There was a correlation between the Fremantle sea level and the Western Australian catch of P . cygnus 3 and 4 years later (Fig. 17.6). There was a weaker correlation between the sea level at Ensenada, Mexico and the Mexican catch of P . interruptus 4 years later (Fig. 17.5). The records of Brazilian sea levels (1949-1968) did not greatly overlap the Brazilian catch records (1 965-1990) and therefore were not used.

-

0.6

WESTERN AUSTRALIA Sealevel with catch

-0.8

1

0

I

I

2

4

I

I

I

I

I

6 8 1 0 1 2 1 4 Lag in years

Fig. 17.5 Correlations between sea level at Fremantle, sea-surface temperature and catches of the spiny lobster Panulirus cygnus in Western Australia. 0'5 0.4

[ MEXICO Sealevel with catch

::::I -0.5

0

I

2

4

I

I

I

6 8 10 Lag in years

I

I

12

14

,

16

Fig. 17.6 Correlations between sea level at Ensenada and catches of the spiny lobster Panulirus interruptus in Mexico, in Baja California.

Spiny Lobster Catches and the Ocean Environment 17.3.3

329

Sea-surface temperature and catch

There was a significant negative correlation between Western Australian SST (Rottnest Station) and Western Australian catch of P . cygnus 1 year later (Fig. 17.6). The correlation with the COADS data was lower (-0.426) with a lag of 2 years. There was a correlation between the Mexican SST and the Mexican catch of P . interruptus 2 years later. There were weaker correlations between the Brazilian SST COADS data and the Brazilian catch of P . argus and P. laevicaudu 2 years later (Fig. 17.7). The COADS SST data off New Zealand were too sparse to yield reliable annual means.

17.3.4

Sea levels and SOI

The relationships between sea level and SO1 were also examined. Western Australian sea level was correlated with SO1 (0.685) at zero lag, as discussed above. Mexico sea level was correlated with SO1 (-0.596) at zero lag. Japan sea level was correlated (0.485) with a 2-year lead, but the reason for this was not obvious. The Brazilian result was not significant (-0.258). Cuba was only just significant, with SO1 lagging sea level by 4 (-0.417) or 5 (-0.432) years. Cuba and Brazil are in the Atlantic Ocean and therefore further removed from the teleconnections of the Pacific/Indian region, so one would expect weaker relationships than in the Western Australian, Mexican and Japanese cases.

BRAZIL Sea surface temperature and catch

-0.5l

0

I

1

I

2

I

3

'

4

I

'

I

I

6 7 8 Lag in years

5

I

I

'

9 1 0 1 1

Fig. 17.7 Correlations between sea-surface temperature and catches of the spiny lobsters Panulirus argus and Panulirus laevicauda in Brazil.

330 Spiny Lobsters: Fisheries and Culture 17.4

Discussion

A whole range of relationships between the spiny lobster catches in the different countries and environmental factors is apparent in these analyses. Although they are at differing time scales between areas they provide a clear indication of the importance of the ocean environment in recruitment to the spiny lobster fisheries, and are thus a guide to more detailed studies in future. The present approach is exploratory and similar to that discussed by Drinkwater & Myers (1987). Relationships between environmental data and lobster catches have been examined by Dow (1977), Campbell et al. (1991) and Fogarty (1986), who showed that catches of both the American lobster Homarus americanus and the European lobster Homarus gammarus are correlated with SST. However, because lobsters are usually caught in traps, these correlations may be based on effects involved with the catching technique, such as the temperature causing changes in catchability of the lobsters. The types of correlation shown in the present study are on a longer time scale and are therefore suggested to indicate effects on recruitment, growth and/or survival of the lobsters. No attempt will be made to explain all the correlations shown here but comments are made on the more interesting of them. The correlations of sea level and catch in Western Australia at 3 and 4 years are clearly in line with previous published results and indicate recruitment times. The correlation of Mexican sea level with catch at 4 years probably also indicates a time to recruitment. Polovina & Mitchum (1992) have shown a relationship between sea levels and recruitment to the P . marginatus fishery in the north-western Hawaiian Islands, 4 years later. The weak Japanese correlations at 8 years are unlikely to be recruitment related, however, and suggest other possible links with fluctuations in the Kuroshio Current, which has a cycle of up to 9 years (Yamanaka et al., 1988). Fushimi (1976) has suggested that currents, particularly the Kuroshio Current, play a major role in the settlement of P . japonicus on the southern coast of the Izu Peninsula. Fogarty (1986) found a relationship between water temperature and catches of the American lobster H. americanus at a lag of 6 years, the approximate time to legal size. Harris et al. (1988) found a positive correlation between lobster catches off New Zealand and westerly winds over Tasmania, but no significant relationship between catch and SOI. However, stronger westerlies off South Australia were found by Pariwono et al. (1986) to occur during non-ENS0 periods (when the SO1 is high), so if similar wind variations apply to the New Zealand area, at about the same latitude, one might expect low New Zealand catches to be associated with ENSO years. In fact, the present results show a negative (although not significant) correlation between catch and SO1 at 4 years’ lag, suggesting that (if the New Zealand lobster takes 4 years to reach recruitment size, as for the Western Australian lobster) high puerulus settlement may occur in ENSO years. The interrelationships are obviously very complex.

Spiny Lobster Catches and the Ocean Environment

33 1

Western Australia and Mexico are linked by an oceanic teleconnection via the equatorial Pacific and the Indonesian throughflow (Godfrey & Ridgway, 1985), and Bye & Gordon (1982) have shown the inverse sea-level relationship that exists between Western Australia and California as a result of ENSO dynamics. Panufirus cygnus and P. interruptus have similar life cycles and, in both cases, high catches follow about 4 years after high sea levels. In non-ENS0 years, Western Australia has a high sea level, an inferred strong poleward current and a good lobster catch, while Mexico has a low sea level, implying a strong equatorward flow (or weaker poleward flow) and poor catch. In ENSO years, low sea levels off Western Australia imply a weak poleward flow and result in a poor catch, while off Mexico a high sea level and inferred stronger poleward flow give a good catch in that fishery. Therefore, in both fisheries, better catches follow high sea levels and stronger poleward (i.e. reduced equatorward) flow. Pringle (1986), who considered the question of the levels of recruitment in the northern portion of the range of the P. interruptus, similarly concluded that it may be episodic, influenced by large-scale, interannual El Niiio events. For the two SST datasets available off Western Australia, the oceanographic station gave a higher correlation with the lobster catches than that from the COADS data. This implies that the narrow Leeuwin Current was more adequately represented by the station data (situated on the outer shelf) than the 2" COADS square. It is possible, therefore, that finer-scale SST data in other fisheries (if available) may give higher correlations than the COADS data used in this analysis. The lack of correlations between some of the lobster catches and the environmental factors examined in this chapter may have been because: (i) there is no relationship (ii) the dataset is insufficiently long (iii) more appropriate datasets could have been selected (iv) there are constraints on the catches, such as quotas, which mean that they do not reflect natural fluctuations in lobster availability. Other researchers will probably be able to comment on points (ii) and (iii); however, this does not remove the overlying conclusions. With regard to (iv), the Japanese lobster catches may fall into this category, as it is known that effort in the fisheries is strictly controlled, but insufficient data are available to determine this point. The New Zealand catch from 1990 is set by quota, hence a larger dataset will not be available. However, the use of catch-per-unit-effort data could eliminate this problem. Other environmental factors could also have been examined. Rainfall has already been shown to affect lobster catches on a seasonal basis in Cuba (Cruz et al., 1986) and Brazil (Fonteles-Filho, 1986), but not the total annual catches. However, Caputi & Brown (1993) have suggested a link between settlement of the western rock lobster and seasonal rainfall at selected sites along the Western Australian coast. Doubtless,

332 Spiny Lobsters: Fisheries and Culture

many other environmental factors may also correlate with lobster catches, supporting the arguments raised in this chapter. Links between the environment and the lobster fisheries may have important implications under conditions of long-term climate change. Pattiaratchi & Buchan (1 99 l), for example, have suggested that under ‘enhanced greenhouse’ conditions, the Leeuwin Current is likely to be weaker at present. On the basis of the results in this chapter, this would indicate lower catches of P . cygnus under a greenhouse scenario. There could well be similar implications for the other fisheries.

References Bayley, G.V. & Hammersley, J.M. (1946) The effective number of independent observations in an auto-correlated series. J . R . Statist. SOC.,B8, 184-97. Breen, P.A. (1988) Rock lobster stock assessment. N . Z . Fish. Assess. Res. Doc. S S j l , N.Z. Ministry of Agriculture and Fisheries, Wellington, New Zealand. Bye, J.A.T. & Gordon, A.H. (1982) Speculated cause of interhemispheric oceanic oscillation. Nature, 296, 5 2 4 . Campbell, A., Noakes, D.J. & Elner, R.W. (1991) Temperature and lobster, Homarus americanus, yield relationships. Can. J. Fish. Aquat. Sci., 48, 2073-82. Caputi, N. & Brown, R.S. (1993) The effect of the environment on the environment on the puerulus settlement of the western rock lobster (Punulirus cygnus) in Western Australia. Fish. Oceanogr., 2,l-10. Caputi, N., Brown, R.S. & Phillips, B.F. (1988) Forecasting rock lobster catches: check and double check. FINS, 21(2), 18-22. Cruz, R., Brito, R., Diaz, E. & Lalana, R. (1986) Ecologia de la langosta (Panulirus argus) a1 SE de la Isla de la Juventud. I. Colonizacion de arrecifes artificiales. Rev. Inv. Mar. (Cuba), VII(3), 3-17. Diggle, P. ( 1990) Time Series: A Biostatisticul Introduction. Oxford Science Publications, Oxford, UK. Dow, R.L. (1977) Relationship of sea surface temperature to American and European lobster landings. J. Cons.. Cons. Int. Explor. Mer., 37, 186-90. Drinkwater, K.F. & Myers, R.A. (1987) Testing predictions of marine fish and shellfish landings from environmental variables. Can. J . Fish. Aquat. Sci., 44, 1568-73. Fogarty, M.J. (1986) Population dynamics of the American lobster (Homarus americanus). Ph.D. thesis, University of Rhode Island, Kingston, RI, USA, 227 pp. Fonteles-Filho. A.A. (1986) Influencia do recrutamento e da pluviosidad sobre a abundancia das lagostas Panulirus argus (Latreille) e Panulirus laevicauda (Latreille) (crustacea: palinuridae). N o Nordeste do Brasil Arq. Cien, 25, 13-31. Fushimi, H. (1976) Ecological contribution to the natural population of Japanese spiny lobster, Panulirus japonicus in the southern coast of the Izu Peninsula. Fish. Eng., 12(2), 2 1 4 . Godfrey, J.S. & Ridgway, K.R. (1985) The large-scale environment of the poleward-flowing Leeuwin Current, Western Australia: longshore steric height gradients, wind stresses and geostrophic flow. J. Phys. Oceanogr., 15, 481-95. Hannah, J. (1990) Analysis of mean sea level data from New Zealand for the period 1899-1988. J . Geophys. Res., 95(B8), 12 399-405. Harris, G.P., Davies, P., Nunez, M. & Meyers, G. (1988) Interannual variability in climate and fisheries in Tasmania. Nature, 333, 7 5 4 7 .

Spiny Lobster Catches and the Ocean Environment

333

Pariwono, J.I., Bye, J.A.T. & Lennon, G.W. (1986) Long-period variations of sea-level in Australasia. Geophys. J.R. Astr. SOC.,87, 43-54. Pattiaratchi, C.B. & Buchan, S.J. (1991) Implications of long-term climate change for the Leeuwin Current. J. R. Soc. W.A., 74, 13340. Pearce, A F & Phillips B.F. (1988) ENS0 events, the Leeuwin Current, and larval recruitment of the western rock lobster. J. Cons. Int. Explor. Mer., 45, 13-21. Pearce, A F & Phillips, B.F. (1994) Oceanic processes, puerulus settlement and recruitment of the western rock lobster Panulirus cygnus. In The Bio-physics of Marine Larval Dispersal (Ed. by Sammarco, P & Heron, M.), pp. 279-303. American Geophysical Union, Washington, DC. USA. Phillips, B.F. (1981) The circulation of the southeastern Indian Ocean and the planktonic life of the western rock lobster. Oceanogr. Mar. Biol. Ann. Rev., 19, 11-39. Phillips, B.F. (1986) Prediction of commercial catches of the western rock lobster Panulirus cygnus. Can. J. Fish Aquat. Sci., 3, 2126-30. Phillips, B.F. (1989) Rock lobster research in Australia. In Workshop on Rock Lobster Ecology and Management. (Ed. by B.F. Phillips). CSIRO Australia Marine Laboratories Report, 1989, Vol. 207, pp. 19-23. Phillips B.F. & Brown R.S. (1989) The West Australian rock lobster fishery: research for management. In Marine Invertebrate Fisheries: their assessment and management (Ed. by J.F. Caddy), Chap. 7, pp. 159-81. J. Wiley, New York, USA. Phillips, B.F. & Pearce, A.F. (1991) Inter-annual variability in ocean circulation and rock lobster recruitment in the south-eastern Indian Ocean. Proceedings of the Symposium on the Long-term Variability of Pelagic Fish Populations and their Environment, Tohoku University, Sendai, Japan, November 1989, p. 98. Phillips, B.F., Pearce, A.F. & Litchfield, R.T. (1991) The Leeuwin Current and larval recruitment to the rock (spiny) lobster fishery off Western Australia. In The Leeuwin Current: An Influence on the Coastal Climate and Marine Life of Western Australia (Ed. by A.F. Pearce & D.I. Walker). J. R . SOC.,W A . 74, 93-100. Polovina, J.J. & Mitchum, G.T. (I 992) Variability in spiny lobster Panulirus marginatus recruitment and sea level in the Northwestern Hawaiian Islands. Fish. Bufl., 90, 483-93. Pringle, J.D. (1986) California spiny lobster (Panulirus interruptus) larval retention and recruitment: a review and synthesis. Can. J. Fish. Aquat. Sci., 43, 2142-52. Weatherdisc Associates (1990) World WeatherDisc Version 2.0. Seattle, WA, USA. Yamanaka, I., Ito, S . , Niwa, K., Tanabe, R., Yabuta, Y. & Chikuni, S . (1988) The fisheries forecasting system in Japan for coastal pelagic fish. F A 0 Technical Paper 301, p. 72.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 18

Measurement of Catch and Fishing Effort in the Western Rock Lobster Fishery N. CAPUTI, C.F. CHUBB, N.G. HALL and R.S. BROWN Bernard Bowen Fisheries Research Institute, Western Australian Marine Research Laboratories, P.O. Box 20, North Beach, Western Australia 6020. Australia

18.1

Introduction

The fishery for the western rock lobster Panulirus cygnus George is one of the major rock (spiny) lobster fisheries in the world and the most valuable fishery for a single species in Australia, accounting for approximately 20-25% of the country’s gross income from fisheries exports. The range of P. cygnus extends from North West Cape (21’44%) to just south of Cape Leeuwin (3424%) on the west coast, from inshore reefs out to depths of 200 m, while the fishery is concentrated between Mandurah (32”43/S) in the south and Kalbarri (27’43’s) in the north a distance of 560 km (Fig. 18.1) and from the inshore reefs out to a depth of 160 m. The 596 boats currently (1998/99) licensed for the three management zones of the fishery (Fig. 18.1), vary in length from 6.6 to 21.5 m, with most boats being 10-18 m. The operators currently operate 56 800 traps (pots) (1998/99) during a 7.5 month season (15 November-30 June). Lobsters are taken with traps of traditional design: stick (or cane) beehive and wooden batten (lath) traps (Morgan & Barker, 1974). Traps are set individually and weather permitting are lifted, rebaited and reset each morning. In deep water greater than 40 m traps are generally left down for 1 4 days. This fishery is also important for recreational fishers. In 1998/99, 32 700 licensed recreational fishers caught about 600 t by potting and diving, equivalent to 4.8% of the commercial catch (see Chapter 24).

18.2

The need for accurate catch and fishing effort statistics

The western rock lobster fishery is considered fully exploited, with an exploitation rate through the entire life after recruitment to the fishery (about 4 years old) of at least 85% and an annual exploitation rate in excess of 60% (Phillips & Brown, 1989; Bowen & Hancock, 1989). At these very high levels of exploitation, researchers and managers depend heavily on annual stock assessments which are based on catch and fishing effort information collected from the commercial fishery. If the catch and/or effort estimates are inaccurate (e.g. underreporting of catch) or biased (e.g. 334

Catch and Fishing Effort in the Western Rock Lobster Fishery

335

W e s t e r n Australia

Indian O c e a n

14'24's

Fig. 18.1 Map of the Western Australian coastline showing the extent of the western rock lobster fishery and the main ports of landing. The fishery is divided into A (Abrolhos Islands) and B zones from 21'44' to 30"sand C zone from 30"s to 34'24'. The 200 m depth contour is also shown.

unmeasured increases in fishing efficiency due to improvements in fishing technology) then the stock assessment, which is based on abundance estimates (e.g. recruit and breeding stock abundance), could be seriously flawed. This could lead to overly optimistic estimates of, in particular, breeding stock levels. This

336 Spiny Lobsters: Fisheries and Culture

chapter examines the approach which has been taken to obtain catch and effort estimates for the western rock lobster; the problems associated with inaccuracies and bias in the long time series of catch and effort data are identified and the process to adjust the data is described. A dynamic spatial model, which uses the adjusted data, has been used to demonstrate the impact of bias in the catch per unit effort (CPUE) measurements (Walters et al., 1993).

18.3

History of the fishery

The fishery began in the 1930s supplying only 250 000 kg of lobster to the local market. An export market was developed in the 1940s and catches increased from 1.0 million kg in 1948 to an average of about 11 million kg/year. The catch for 1998/99 was a record at 13 million kg, worth about Aus $240 million to the fishers. During the 1960s and 1970s over 90% of the catch was exported as frozen tails to the USA. More recently, the largest consumer nations, apart from the USA (19%), have been Japan (31%), Taiwan (40%) and China/Hong Kong (10%) (Western Rock Lobster Development Association). The types of product have also diversified to frozen whole cooked (35%), frozen tails (21%), frozen whole raw (8%) and live (35%). The potential of the European market is being assessed to reduce reliance on the Japanese and Taiwanese market. Since 1963, entry to the fishery has been limited (‘limited entry’) (Hancock, 1981) with the objectives of optimal utilization of the resource, reasonable economic return to the fishers, and orderly exploitation to minimize conflicts among commercial fishers and between commercial and recreational fishers. Table 18.1 describes the chronology of major management regulations that control exploitation of the stock. The main thrust of management measures has been to contain the continued increases in fishing effort and efficiency that have occurred despite the early introduction of a strict limited entry management regime.

18.4

Biology and life history

Mating in P . cygnus takes place in winter-spring (July-November) and eggs are extruded and fertilized from October to December. The eggs are carried on the pleopods for 3-9 weeks before hatching, with the incubation period being inversely related to water temperature. On hatching, the larvae (phyllosoma) move to the surface, where wind-driven currents carry them offshore and distribute them over a wide area of the south-east Indian Ocean. Larvae spend 9-1 1 months feeding and developing through a series of instars before subsurface currents carry them back to the coast (Phillips et af., 1979). The puerulus stage completes the oceanic cycle by swimming across the continental shelf and settling in the shallow limestone reef areas along the coast (Phillips, 1981).

Catch and Fishing Effort in the Western Rock Lobster Fishery

337

Table 18.1 Major management regulations controlling exploitation of the stock Year/season

Regulation

1897

Minimum legal whole weight of 12 oz (340 g). This measurement is equivalent to, and eventually evolved into, the 76 mm carapace length minimum size currently in force in the fishery Females carrying spawn were given full protection by requiring them to be returned to the sea Closed seasons: coastal fishery 16 August-14 November; Abrolhos Islands fishery 16 August-14 March Limited entry introduced: boat numbers were fixed (858) and the number of traps per boat was limited to three per foot (0.9 mm) length of boat Boat replacement policy required a boat to be replaced with one of exactly the same length. This stopped fishers replacing a boat with a larger one and hence obtaining additional traps to use under the three traps/foot of boat length regulation. This froze the total number of traps in the industry at 76 623 A 51 x 305 mm escape gap was introduced into all traps to allow sublegal size lobsters to escape before the trap is brought to the surface Escape gap was increased to 54 x 305 mm Multiple entrances in traps were banned Fishing season was shortened by 6 weeks from 15 November-15 August to 15 November-30 June to protect newly mated females and to constrain fishing effort Boat replacement policy was changed to allow a boat’s trap quota (entitlement) to vary from seven to 10 traps per metre of boat length. This gave fishers flexibility in the size of the replacement boat that they could have for a given trap quota Maximum size for traps was established based on a maximum volume of 0.257 m3 Number of escape gaps (54 x 305 mm) in traps was increased (from one) to three or four (depending on the position of gaps) Trap numbers of all licence holders were reduced temporarily by 10% for the 1986/87 season. Total trap numbers were reduced from 76 623 to 68 961 for one season Trap numbers were reduced permanently by lo%, at 2% per year for 5 years 10% reduction in traps in zone B (1 5 November-9 January) Closure in zone B (10 January-9 February) Return of setose females (November-February) Maximum size for females (1 15 mm) Home porting in zone C 18% reduction in traps Minimum size increased to 77 mm in November-January Return of females which were setose or above a maximum size (105 mm zones A and B and 115 mm zone C)

~~

1899 1962 1963 1965

1966 1971/72 1973 1977178 1979

1984 1986 1986 1987-1991 1992/93

1993/94

See Brown (1991) for the reasons for trap reductions, pot dimension restrictions and increases in the number of escape gaps.

338 Spiny Lobsters: Fisheries and Culture During their first years as benthic juveniles they live in holes and crevices in the reef (Fitzpatrick et al., 1989). During daylight the older juveniles are found under the limestone reef ledges but at night they forage for food in the surrounding sea-grass beds (Joll & Phillips, 1984). When juveniles are between 4 and 6 years old, they emigrate offshore from the shallow reef areas into depths of 30-150 m (George, 1958). This migration occurs regularly in November-January each year and is made up of immature, very pale, newly moulted animals called ‘whites’ (Morgan et al., 1982). During the remainder of the year, February-October, the rock lobsters are non-migratory, having returned to their darker coloration and are known as ‘reds’. The minimum legal size for this fishery [carapace length (CL) 76/77 mm] is generally less than the size at first breeding of females, although this size varies along the coast (Morgan, 1972; Chubb et ul., 1989; Chubb, 1991). Reproductive maturity of females in the coastal situation generally occurs 1-2 years after the migration to deep water. However, at the offshore Abrolhos Islands, the majority of breeding females are below 76 mm CL (Chubb et al., 1989, Chubb, 1991, Chubb, Chapter 14).

18.5 18.5.1

Data used in stock assessment Commercial fishing information

There are three major sources of catch and fishing effort data available from the commercial fishery. 1. Compulsory monthly returns: since 1944/45 all fishers have provided monthly the weight of their landed catch (kg) by 1 x 1” statistical blocks, the number of days fished, and the average number of traps lifted per day. The number of traps lifted is used as the basic measure of fishing effort. 2. Voluntary research log books records: these have been completed by 20-40% of the fleet since 1964/65 and contain daily records of catch (kg) and fishing effort (number of traps lifted) by 10 x 30’ blocks for depths of 0-18 m, 18-37 m, 37-55 m, 55-73 m and over 73 m, soak time, numbers of females which are berried, setose and above the maximum size (regulations require their return to the sea). Estimates of the number of octopus caught, undersized rock lobsters caught and returned to the sea, and information on the wind, swell and current conditions are also recorded in an optional section. 3. Compulsory processors’ monthly returns: the 17 licensed (and operating) processors provide information on the weight of live catch supplied by each fisher and details of processed rock lobsters by weight and eight different grade (size) categories (Brown & Barker, 1985).

Catch and Fishing Effort in the Western Rock Lobster Fishery 18.6

339

Research programmes

There are two research monitoring programmes that provide data on the size and sex ratio of the commercial catch and abundance estimates of different life history stages. 1. Commercial catch monitoring: since 1971/72 research staff have undertaken an onboard commercial monitoring programme for each month of the season from four depth categories (CL18 m, 18-37 m, 37-55 m and greater than 55 m) at each of four coastal locations (Dongara, Jurien, Lancelin, Fremantle; Fig. 18.1) and the Abrolhos Islands. CL, sex and breeding state are recorded for each lobster caught. On occasion, sampling of the landed catch is done at various processing plants along the coast. 2. Puerulus settlement: the last oceanic stage, the puerulus, of P . cygnus can be captured using collectors constructed using artificial seaweed. Collectors stationed at 10 sites throughout the fishery are serviced monthly to provide an annual index of puerulus settlement. Data are available from some sites from 1968. The settlement index obtained from these collectors provides an understanding of the annual variation in recruitment and can be used to predict the catch 3 and 4 years later (Caputi et al., 1995a, b).

18.7

Abundance estimates

There are three life history abundance estimates, besides the puerulus settlement index, that are used to assess the status of the fishery. Abundance of pre-recruits: abundance estimates of pre-recruits are based on catch rates of undersize rock lobsters obtained from commercial monitoring data. These animals are 1 or 2 years away from entering the fishery. The estimates are used to confirm the catch predictions made using puerulus settlement (Caputi & Brown, 1986; Caputi et al., 1995b). The introduction of three or four escape gaps in 1986/87 has reduced the numbers of undersize and reduced the reliability of this index but they still provide a good indicator of the catch. Abundance of recruits to thefishery: during late November of each year, large numbers of immature, newly moulted, pale-coloured rock lobsters emigrate into deeper water from the shallow-water inshore reefs where they have spent the previous 3 or 4 years. This offshore movement normally continues into January, for about 6-8 weeks. Because the lobsters are newly moulted, food requirements are high (Chittleborough, 1975) and they are very catchable. The migration further adds to increased catchability by baited traps at this time (Morgan, 1974). Many of these animals have moulted from undersize to above legal size, or larger, which enables the catch rates to be utilized as a measure of recruitment to the fishery. In the same way, the catch rates during late February, March and

340 Spiny Lobsters: Fisheries and Culture early April can also be used as a recruitment index, following a second synchronized moult (no migration) in February. 3. Spawning stock abundance: an index of the spawning stock has been obtained each season from 1964 from the catch rates of berried females in 37-55 m during December and January, which are recorded in research log books. Other estimates of the abundance of the spawning stock have recently been developed (Chubb et al., 1989; Caputi et al., 199%; Chubb, Chapter 14) and are based on catch rates of mature size classes obtained from a commercial monitoring programme from various sectors of the fishery. An independent breeding stock survey at five coastal locations and at the Abrolhos Islands has also been developed (Melville-Smith et al., 1998).

18.8

Other programmes

Two detailed studies (Norton, 1981; Chubb et al., unpubl. data) and annual mail surveys have provided estimates of the recreational catch and effort. Numerous other research studies have been conducted on many aspects of the life history, biology and population dynamics of the western rock lobster. Extensive reviews of this literature are found in Cobb & Phillips (1980), Hancock (1981), Phillips & Brown (1989) and Brown (1991). Economic studies of the fishery were undertaken in 1974 and 1978 by the Australian Commonwealth Department of Primary Industry (Meany, 1981). Lindner (1994) examined the economic efficiency of input- and output-based management systems, while Monaghan (1989) and Marec (1994) examined some marketing aspects of the western rock lobster fishery.

18.9 18.9.1

Inaccuracies and bias in the data

Illegal fishing activities

During the 10-15 years after limited entry was introduced (1963 to the mid-1970s) some fishers adopted a cavalier approach to the regulations protecting undersize and spawning animals and to the number of traps they used. There are, for example, anecdotal reports from the early 1960s of large numbers of undersize rock lobsters being transported out of Western Australia, under the guise of ‘frozen chickens’. Fishers breaching regulations were possibly encouraged by the relaxed approach to enforcement during the early 1960s and by the limited resources available to fisheries enforcement officers at that time. In the early 1970s, better resourced fisheries enforcement officers became more innovative and, backed by harsher penalities, were able to enforce the regulations. By the mid-1970s the

Catch and Fishing Effort in the Western Rock Lobster Fishery

341

regulations were generally accepted by the industry and since that time few serious breaches have been detected. Such illegal activities in the early years of the fishery obviously affected the integrity of the data reported by fishers. Undersize rock lobsters were either not delivered to processing establishments or, if they were, they were not recorded by the processors, nor were they reported in fishers’ mandatory monthly returns. The reported catch landings, therefore, are understated. Egg-bearing females were landed to processing establishments after the eggs had been removed (scrubbed) from the tails. While the females that had their eggs removed were included in the reported landings and in the monthly returns, it is of value to note the quantities landed, in order that models of the fishery make appropriate use of the data. Use of traps in excess of the legal entitlement resulted in understated levels of effort on monthly returns. To assess the impact of these activities interviews were conducted and a questionnaire was circulated to fishers in 1985 and completed anonymously. Analysis of the responses is shown in Table 18.2. The time series of recorded catch and effort figures have then been adjusted using these estimates and the number of prosecutions, under the Fisheries Act, for various offences committed during this period.

18.10

Taxation considerations

A source of bias results from the understatement of catch on fishers’ compulsory monthly catch and effort returns in an attempt to minimize taxation. This bias is believed to affect only the catch component of the monthly return, not the fishing effort. However, these unreported catches have been reported by some processors as cash sales although not as a catch attributed to a particular vessel, and therefore do not result in a biased measure of the total catch from this source. On average, the difference between the processors’ total catch and total catch declared by fishers has been about 5%. Correction of the fishers’ monthly return data for cash sales to processors has been achieved by using the ratio of landings received by processors to the total catch recorded by all licence holders. An unquantifiable but insignificant proportion of the catch goes unrecorded through the very small local market by way of direct sales to retail outlets and consumers. Figure 18.2 compares the catch from the original database, as obtained from fishers’ monthly returns, to the catch adjusted for the illegal take of undersize rock lobsters and understated catches. Since the early 1990s processors have been required by the Australian Tax Office to record the vessel details for all receivals and this has significantly reduced the level of unreported cash sales.

342 Spiny Lobsters: Fisheries and Culture Table 18.2 Estimate of undersize rock lobsters as a percentage of the annual catch, the percentage of spawning rock lobsters in the annual catch and the percentage of traps used in excess of the licensed number of traps Fishing season 1957158 1958159 1959160 1960161 1961/62 1962163 1963164 1964165 1965166 1966167 1967168 1968169 1969170 1970171 1971172 1972173 1973174 1974175 1975176 1976177 1977178 1978179 1079180 1980181 1981/82 1982183 1983184 1984185

YOundersize

% spawners

NA NA NA NA NA 3.6 4.4 4.3 4.3 7.6 7.1 7.3 6.7 6.4 5.8 5.0 5.7 5.4 4.0 2.5 1.5 0.7 0.6 0.4 0.4 0.3 0.3 0.1

NA 1.2 1.1

1.o 0.4 0.4

0.4 0.4 0.3 0.0

0.0

0.0 0.0 0.0 0.0

0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

% traps

NR NR NR NR NR 19.4 17.0 21.5 19.6 23.8 19.1 14.2 7.3 4.7 2.9 1.8 1.o 0.0 0.0

0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

NA, not available; NR, no restriction (on trap numbers).

18.11

Adjustment using research log book

Data recorded on a monthly basis can be biased, since they are based on the accuracy of the records maintained by the licence holder. The monthly data are supplemented by the more detailed daily research log-book records provided by a

Catch and Fishing Effort in the Western Rock Lobster Fishery

0

1,. .#. .

1940

.,

,

,

. . . . ,. . , . . . . . . , .. , . . .

1950

1960

1970

, ,

...,,, ... ., , , ,

1980

343

~

1990

Year Fig. 18.2 Time series of catch (kg) for the western rock lobster fishery obtained from fishers' monthly returns (A) compared with the catch adjusted for illegal activities (sale of undersize animals) and underreporting of catch to avoid tax (B). subset (2&40%) of the licence holders. These log books are believed to reflect more accurately the catch rates observed in the fishery. These data can be merged with the data from the monthly returns. To do this, the daily data are first summarized to the same level of spatial and temporal resolution of the monthly data: that is, monthly log-book catch and effort are calculated for each 1" block (grid) square. The ratio of the monthly catch from the mandatory monthly returns (corrected using processor's returns) to the summarized log-book catch for the same block and time period is calculated, to provide a measure of the weighting that needs to be applied to each log-book record in that block when combining it with other data. The weighting is applied equally to log-book catch and effort. These data then represent the detailed catch and effort data derived from validated log books, corrected for the sampling intensity of the log-book programme and adjusted to agree with the total catch for the entire fishery.

18.11.1

Recreational catch

An assessment of the catch of rock lobsters by the recreational fishery has been estimated at 2 4 % of the total commercial catch, rising to 15% in shallow-water areas close to the two major centres of population (Perth and Geraldton; Fig. 18.1)

344 Spiny Lobsters: Fisheries and Culture (Norton, 1981; Chubb et al., unpubl. data). More recently, the recreational component of the total catch has been about 4 5 % (see Chapter 24).

18.11.2

Soak time

Morgan (1979), using research log-book data (up to the mid- 1970s), found no significant difference in the catch rates associated with traps lifted following I , 2 or 3 days soak time and, therefore, ignored the effect of soak time. Subsequent analysis of more recent research log-book data and specifically designed field programmes has shown significant variations in catch rates with soak time, especially in waters greater than 40 m. Table 18.3 shows the percentage difference in catch rate of a 2day soak compared to a 1-day soak, for the two depth ranges 0-18 m and 36-54 m for the northern and southern sectors of the fishery during 1989 and 1990. Overall, 2-day soaks give better catch rates than 1-day soaks, except in the shallow waters of the northern sector of the fishery. This difference is probably due to the much greater densities and smaller animals in this part of the fishery, paarticularly in shallow water. This may produce trap saturation and/or exhaustion of the bait, which reduces the catchability of the trap more rapidly than occurs with the lower densities of larger animals in the southern sector of the fishery and in deeper water. Other factors that may affect the catch rates of 2-day soaks are the types of trap used and the nature of the fishing grounds. Overall catch rates for soak periods greater than 3 days in both shallow and deep water, fell to the same levels as, or below those of 2-day soaks. The number of times that fishers leave traps unpulled for 3 days or greater is insignificant (<5%) compared with 1- and 2-day soaks. As yet, the significant increase in catch rates for the longer soak period has not been incorporated into the fishing effort database to increase the overall efficiency of the trap lifts. This correction will be needed by fishery sector and depth. The proportion of I-day soaks versus 2-day soaks over the time series of data will be required.

Table 18.3 Percentage difference (higher or lower) of the catch rate of a 2-day soak compared with a 1-day soak averaged for 1989 and 1990 Depth

Zone B (north; above 30"s)"

Zone C (south; below 30"s)"

0-1 8

-6% 18.5%

18.0% 46.5%

(m)

36-54

aSee Fig. 18.1.

Catch and Fishing Effort in the Western Rock Lobster Fishery 18.11.3

345

Calculation of effective effort and changes in fishing power

Morgan (1979) discussed the factors that might affect the catches of rock lobster, and concluded that the 'trap lift' provided an adequate measure of nominal effort. He argued that the method of fishing and design of traps had remained relatively unchanged since the fishery began through to the mid- 1970s. While acknowledging that the type of bait used had varied, he considered that this reflected availability of bait rather than improved catching power. Apart from the introduction of echo sounders in the 1950s and hauling winches in the 1960s, there had been little improvement in the ability of fishers to locate and fish rock lobster habitat. Morgan (1979) also described the method used to estimate effective effort for the Western Australian rock lobster fishery. The monthly effort in each 1 x 1" fishing block is first multiplied by the relative vulnerability for that month. The latter is calculated as the average monthly catchability, as estimated by Morgan (1974), relative to the average catchability for January, where the vulnerability is assumed to be 1. The monthly values of recorded catch and effort are then summed for each block to produce annual totals. The average catch rate for the fishery is then calculated, using the method described by Gulland (1969), as the weighted average catch rate over the fishing blocks, using the area of each block (grid) as a weighting factor: blocks used in this calculation represented those which had been fished intensively during the history of the fishery. Finally, effective effort is calculated by dividing the average catch rate into the total catch for the fishery. Subsequent review of this algorithm indicated that inclusion of data from some blocks fished infrequently resulted in undue influence on the estimate of effective effort (Phillips & Brown, 1989). Therefore, the method was revised to exclude blocks on the fringe of the fishery that sporadically produced small catches but high catch rates (Hall & Brown, 1995). Only parts of blocks where depth was less than 200 m were included, and the area associated with these waters in each block was calculated. Morgan (1980) noted that nominal effort in the fishery, which was closely related to the effective effort, continued to increase from 1964/65 to 1975/76, as a consequence of an increase in the mean number of boats working each month, mean number of days worked per boat per month, and mean number of traps worked per boat. During this period, latent fishing effort was activated. Morgan attributed the increase to personal (and financial) decisions by fishers rather than to technological improvements in boats and gear. Another factor was the significant increase in price, which made it profitable for fishers to operate during periods of lower catch rate. In the late 1940s when the rock lobster fishery started in earnest, fishers used small boats, with small motors and auxiliary sails. Traps were pulled by hand, which limited the area of fishing to shallow waters. Over the years, the fishing capability of the boats has increased as a result of better design, higher speeds, bigger size and the introduction of hydraulic trap winches. Since Morgan's work to the mid-l970s, dramatic changes have occurred in the rock lobster fleet, through vessel design,

346 Spiny Lobsters: Fisheries and Culture construction and materials, innovations in fishing gear and the application of satellite technology to fish finding and navigational equipment. The current rock lobster fleet is more efficient today than in the past, and the fishing effort is increasing despite the fact that boat and trap numbers have been reduced since 1963. The improved seaworthiness of boats allows fishers to pull all of their traps almost every day if they desire, and the number of days fished per month has increased steadily from 15.2 in 1964/65 to 17.5 in 1976/77, when the open season was from 15 November to 14 August, and from 19.7 in 1977/78 to 21.6 in 1990/91, when the open season was from 15 November to 30 June. The new boats can now move their entire trap quota quickly from one area to another with a higher catch rate. The electronic fishing aids now available include sophisticated colour echo sounders (providing greater definition of substrate type and bottom topography), radar, satellite global positioning systems (GPS) and computer plotting. In addition, despite measures taken in the past to limit more effective trap designs, traps are constantly being improved, e.g. with larger bait containers. The individual skill and rate of knowledge accumulation of the fishers has also increased over time, especially with the use of GPS and computerized catch databases. All of these improvements indicate that the catching power of a rock lobster trap is much greater than it was 20 years ago and the rate of efficiency increase over the past 5-10 years has been significant. Figure 18.3 shows the changes that have occurred in rock lobster boats from the 1950s to the 1990s. An example where the increases in effective effort and fishing power have had a marked impact on the fishery has been at the Abrolhos Islands. The Abrolhos Islands zone of the fishery (Fig. 18.1) is unique in that half of the fleet (148) in the northern sector (above 30"s) is authorized to fish there from 15 March to 30 June. The Abrolhos provides about 1618% of the total catch each season and is considered to be a reliable fishing area with only small fluctuations in catch (<20%). When the Abrolhos Islands season opens on 15 March, fishers work very hard to take advantage of the accumulated stock that provides high catch rates. As the season progresses the catch rates decline rapidly, until they reach relatively low levels by May. In the early 1970s the catch rate at the beginning of the season averaged 2.4 kg/trap lift (1969/70 to 1972/73) and 30 days later had declined to 1.4 kg/trap lift (Fig. 18.4). By the late 1980s this trend in catch rates for the first 30 days of the season had altered significantly. Figure 18.4 shows the average catch rates for the four years 1985-1987 and 1988-1990 combined. At the start of the season the average catch rate was 4.4 kg/trap lift and 30 days later had declined to 1.1 kg/trap lift. The Abrolhos Islands fleet of the late 1980s was able to deplete the legal size stocks at the Abrolhos Islands far more rapidly than the fleet of 16 years previous. A detailed study to quantify the changes in boats, gear and equipment was undertaken to determine the impact that they may have had on the effectiveness of fishing operations. Figures 18.5 and 18.6 show examples of the trends that have taken place in the fleet from 1971 to 1990, i.e. in boat length, area and engine HP, GPS and satellite navigation, colour echo sounder and bait usage. Fishing power

Catch and Fishing Effort in the Western Rock Lobster Fishery

347

Fig. 18.3 Typical western rock lobster boats used in: 1950s; 1960s; 1970s; and 1980s/90s (clockwise from top left).

analyses have shown that GPS, colour echo sounder and radar have had a significant impact on catch rates, particularly in deep water during the non-migratory part of the fishery (February-June) (Brown et al., 1995; Fernandez et al., 1998). From preliminary analysis of these data a schedule of estimated efficiency increases over the 21-year period, 1971-1991, was produced to allow adjustment of

348 Spiny Lobsters: Fisheries and Culture 4.6

4.0

3.5

2i

a

cn

Y

2.5

2.0

1.5

1.o

Days

Fig. 18.4 Catch rates (kg/trap lift) of western rock lobsters achieved at the Abrolhos Islands by the fleet of the early 1970s (A), compared with the fleet of the late 1980s (B).

the nominal trap lifts. Adjustments to the effective effort as measured by Morgan (1979) and Hall & Brown (1995) are currently in progress. Separate adjustments are now made to fishing effort expended in shallow water (0-40 m) and deep water (240m) at a rate of about 1-1.5% and 2-3% per year, respectively (Table 18.4). These estimates are considered to be conservative by researchers, managers and the fishing industry. Figure 18.7 shows nominal fishing effort (trap lifts) compared with fishing effort adjusted for illegal overpotting activities and increases in fishing efficiency. Table 18.4 Estimated increases in fishing efficiency used to adjust nominal fishing effort and model the fishery to determine the effect on egg production and catch

Shallow water ( 0 4 0 m) Deep water (240 m)

1971-199 1

1971-20 10

26% 54%

35% 69%

Catch and Fishing Effort in the Western Rock Lobster Fishery

/

1971

1973

1975

1977

1979

1981

1983

1985

349

Bait Usage

/'-,

1987

1989

Year

Fig. 18.5 Trends in boat length, boat area, engine horse power and bait usage (Abrolhos Islands area) in the western rock lobster fishery from 1971 to 1990.

18.12

Impact of increases in fishing efficiency on abundance estimates

The four major indices of abundance that are affected by the increases in fishing efficiency are pre-recruit and recruit abundance, spawning stock abundance, and total population abundance based on overall catch rates. It should be noted that the effect of increases in fishing efficiency may not be uniform throughout the fishing season, owing to changes in abundance. The effect of factors such as improved fish-finding devices (colour echo sounder, GPS, etc.) and the ability to be able to move traps rapidly to high catch areas are most effective when there are large differences in catch rates between areas. As the variance in catch rates between areas declines as a result of fishing down of the high-abundance areas, the effect of these factors should also diminish. The other aspect of increasing fishing efficiency, that is, the ability of the traps to catch animals (e.g. more attractive longlasting baits, trap designs reducing escape) is not affected in the same way by declining catch rates. Chubb (Chapter 14) shows how the estimates of spawning stock abundance, which appear stable when nominal (unadjusted) fishing effort is used, in fact, decline once

350 Spiny Lobsters: Fisheries and Culture

1971

1973

1975

1977

1979

lm

lge3

1985

1987

1-

Year Fig. 18.6 Trends in the aquisition of colour echo sounders and satellite navigation and global positioning systems in the western rock lobster fishery from 1971 to 1990.

the estimated increases in fishing efficiency are incorporated. This trend increased concern in the early 1990s amongst researchers, managers and the fishing industry as to the longer term maintenance of the spawning stock. This resulted in the introduction of a management package in 1993/94 (Table 18.1), which has caused a marked increase in the breeding stock. The overall catch rate, which can be used as an estimate of relative population abundance, is also affected by the estimated increases in fishing efficiency. Figure 18.7 shows the catch rate C [adjusted catch (kg)/trap lift] for the fishery using nominal (unadjusted) effort compared with the catch rate D obtained after adjusting the effort for increases in fishing efficiency and overpotting. While the trend in catch rate based on nominal effort indicates that the abundance of rock lobsters has remained stable since the mid 1970s, the catch rates based on estimates adjusted for efficiency show that there has been a gradual decline.

18.13

Assessment of the western rock lobster stocks

The extensive and adjusted database developed for the western rock lobster fishery has been used by Walters et al. (1993) to develop a complex spatiotemporal model to enable the status of the stock to be assessed and to test the impact of proposed management strategies on the breeding stock, catch, effort, etc. Various levels of

Catch and Fishing Effort in the Western Rock Lobster Fishery 2.0

16

g-

14 12

1.5

c

a"

. I -

351

3

h

c

0

10

a, ol

0

1.0

!28

.-0 c 6 r

0.5

g 4 w

9

a" r 8Y

2

0 1940

1950

1960

1970

1980

0.0 1990

Year

Fig. 18.7 (A) Nominal fishing effort (trap lifts), compared with (B) fishing effort adjusted for illegal over potting activities and increases in fishing efficiency. ( C ) Catch rate using adjusted catch (kg) and nominal fishing effort compared with (D) adjusted catch and adjusted fishing effort.

assumed efficiency have been incorporated to determine their potential impact on the estimates of spawning stock/egg production and catch. Using nominal fishing effort, with no adjustment for increases in efficiency (past or future), the model showed that egg production stabilized at about 20% of the virgin biomass production (Fig. 18.8) and catch remained steady (Fig. 18.9). When fishing effort was adjusted to reflect the increases in fishing efficiency that are estimated (conservatively) to have taken place

Year Fig. 18.8 Fishery model outputs showing egg production using: (A) nominal fishing effort (no adjustment for increases in fishing efficiency); (B, C) fishing effort adjusted for fishing efficiency increases as laid down in Tables 18.4 and 18.5, i.e. approximately 1.5% and 3.0% increase per season in 197 1-2010, respectively.

352 Spiny Lobsters: Fisheries and Culture

Y Y-

0

2

1412-

lo-

0 = 8-

5

v

.c

s 0

c.

6420)

1

4

I

1

Year Fig. 18.9 Fishery model outputs showing catch (kg) using: (A) nominal fishing effort (no adjustment for increases in fishing efficiency); (B, C ) fishing effort adjusted for increases in fishing efficiency as laid down in Tables 18.4 and 18.5, i.e. approximately 1.5% and 3.0% increase per season in 1971-2010, respectively.

(and will continue to take place) (Table 18.4), predicted egg production continued to decline slowly into the future (Fig. 18.8); however, predicted catches remained steady (Fig. 18.9). When larger increases in fishing efficiency are assumed (Table 18.5), the resulting decline in egg production is more rapid (Fig. 18.8) and reaches a level where it falls below that which is assumed to be required to maintain recruitment at historic levels and, hence, catches decline significantly (Fig. 18.9). To enable the catch trends from the model outputs to be seen more clearly, no environmental effect on predicted recruitment (i.e. constant recruitment is assumed) has been used, as defined by Walters et al. (1993). The current breeding stock size is adequate to sustain recruitment and it is the strength of the Leeuwin Current (Pearce & Phillips, 1988; Pearce, 1989) and winterspring storms (Caputi & Brown, 1993; Caputi et al., 199%) that are considered to be the main factors controlling the level of puerulus settlement. Therefore, the level of settlement varies widely from year to year, and this in turn affects the subsequent number of recruits in later years. A run of years with poor environmental conditions can reduce the level of recruits to the fishery and hence also the size of the subsequent breeding stock. Table 18.5 Large increases in fishing efficiency used to adjust nominal fishing effort and model the fishery to determine the effect on egg production and catch

Shallow water (0-40 m) Deep water (240 m)

1971-1991

1971-201 0

52% 84%

72% 150%

Catch and Fishing Effort in the Western Rock Lobster Fishery

353

Concern over the state of the breeding stock has been heightened in recent years owing to the advent of GPS, which enable fishers to fish the offshore deep-water breeding grounds and return to the exact location (within 15 m) at any time. Similarly, advanced colour echo sounders provide enhanced definition of sea-bed topography, which allows more accurate identification of lobster habitat. Both of these new technologies have the potential to focus greater and more effective fishing effort on the breeding stock in deep water, thereby further reducing the stock and bringing it closer to the point where average recruitment declines as a result of low spawning stock. This was one of the reasons for the introduction of the 1993/94 management package (Table 18.1) which, at the time of writing (1998/99), is still operating.

18.4

Discussion

The maintenance of accurate catch and fishing effort databases that incorporate increases in fishing efficiency which are not measured by the baseline (nominal) effort measurement (in this case trap lifts) is vital to realistic stock assessments. Without a fully validated time-series data set, it is likely that an overoptimistic and hence misleading assessment of the state of the stock (especially the breeding stock) will be made. Accurate assessment of catch and effort information involves more than just setting up a log-book system. It requires proper validation, an assessment of changes in distribution and timing of fishing and changes in fishing efficiency caused by innovations in boats, gear and technology. When fisheries databases are initially established, a number of independent sources of data needs to be cross-referenced so that the total catch, in particular, can be accurately estimated. Records of fishing effort need to document innovations and changes in all aspects of boats, fishing gear (including bait) and fish-locating technology. Since 1989, all rock lobster fishers have been required to supply details of gear and technology used on an annual basis. Details of boat replacements are also recorded. Hence, a detailed database on each boat’s characteristics and use of gear and technology is maintained. Indeed, fisheries managers and industry alike are of one mind to minimize the negative impacts of new technology on the breeding stock. The Rock Lobster Industry Advisory Committee (RLIAC), which is comprised of one recreational and eight commercial fishers, two processors and two government representatives, recommended to the Western Australian Minister of Fisheries that before fishers acquire new innovations in gear to technology, the industries management committee, which advises the Minister, should recommend whether or not it should be introduced into the fishery. If more efficient technology or gear is to be introduced into the fishery, a corresponding decrease in effort (fishing mortality) may be needed to protect the breeding stock.

354 Spiny Lobsters: Fisheries and Culture It must be remembered that the fishers are the vital link in the data-gathering process. Therefore, it is essential that the relevance and importance of the information that they supply is communicated to them so that they record data accurately. This feedback is achieved in the western rock lobster fishery by providing those fishers who participate (approximately 200 boats) in the log-book programme with three or four updates each season on how the catch (total) is progressing and an annual summary of their catch and effort by depth, compared with the average for their sector of the fishery. In addition, the RLIAC and research staff meet with commercial fishers before the start of each season, at five coastal locations, to discuss the status of the stock and to obtain feedback from the industry concerning proposed management measures. Research staff also attend regular meetings with fishers’ associations along the coast, and/or their management representatives, during the season, to bring them up to date with the latest assessment of the fishery and to explain how the data that they provide are used in the assessment.

Acknowledgements We thank our colleagues at the Western Australian Marine Research Laboratories for critically reading the manuscript and offering many helpful suggestions.

References Bowen, B.K. & Hancock, D.A. (1989) Effort limitations in the Australian rock lobster fisheries. In Marine Invertebrate Fisheries: Their Assessment and Management (Ed. by J.F. Caddy), pp. 375-93. Wiley, New York, USA. Brown, R.S. (1991) A decade (198g1990) of research and management for the western rock lobster (Panulirus cygnus) fishery of Western Australia. Rev. Invest. Mar., 12, 204-22. Brown, R.S. & Barker, E.H. (1985) The western rock lobster fishery 198g81. Fish. Dep. West. Aust. Rep., 72, 22 pp. Brown, R.S., Caputi, N. & Barker, E.H. (1995). A preliminary assessment of the effect of increases in fishing power on stock assessment and fishing effort of the western rock lobster (Panulirus cygnus George 1962) fishery in Western Australia. Crustaceana, 68, 227-37. Caputi, N. & Brown, R.S. (1986) Relationship between indices of juvenile abundance and recruitment in the western rock lobster (Panulirus cygnus) fishery. Can. J . Fish. Aquat. Sci., 43, 2 13 1-9. Caputi, N. & Brown, R.S. (1993) The effect of environment on puerulus settlement of the western rock lobster (Panulirus cygnus) in Western Australia. Fish. Oceanogr., 2, 1-10. Caputi, N., Brown, R.S. & Chubb, C.F. (1995a) Regional prediction of the western rock lobster, Panulirus cygnus, catch in Western Australia. Crustaceana, 68, 245-56. Caputi, N., Brown, R.S. & Phillips, B.F. (1995b) Prediction of catches of the western rock lobster (Panulirus cygnus) based on indices of puerulus and juvenile abundance. ICES Mar. Sci. Symp., 199, 287-93. Caputi, N., Chubb, C.F. & Brown, R.S. (199%) Relationship between spawning stock, environment, recruitment and fishing effort for the western rock lobster, Panulirus cygnus, fishery in Western Australia. Crustaceana, 68, 213-26.

Catch and Fishing Effort in the Western Rock Lobster Fishery

355

Chittleborough, R.C. (1975) Environmental factors affecting growth and survival of juvenile western rock lobsters Panulirus Iongipes (Milne-Edwards). Aust. J . Mar. Freshwat. Res., 26, 177-96. Chubb, C.F. (1991) A study of the spawning stock of the western rock lobster. Rev. Invesf.Mar., 12, 223-3 3. Chubb, C.F., Dibden, C. & Ellard, K. (1989) Studies on the breeding stock of the western rock lobster, Panulirus cygnus, in relation to stock and recruitment. FIRTA project 85/57 Final Report. Cobb, J.S. & Phillips, B.F. (Eds.) (1980) The Biology and Management of Lobsters, Vols. I and 11. Academic Press, New York, USA. Fernandez, J., Cross, J., Caputi, N. (1998). The impact of technology on fishing power in the western rock lobster (Panulirus cygnus) fishing. In Proceedings of the International Congress on Modelling and Simulation (Modsim 97) (Ed. A.D. McDonald and M. McAleer), 4, 1605-10. Fitzpatrick. J, Jernakoff, P. & Phillips, B.F. (1989) An investigation of the habitat requirements of the post puerulus stocks of the western rock lobster. Final Report to the Commonwealth Government of Australia Fishing Industry Research and Development Council, 80 pp. George, R.W. (1958) The status of the white crayfish in Western Australia. Aust. J. Mar. Freshwat. Res., 9, 53745. Gulland, J.A. (1969) Manual of methods for fish stock assessment. F A 0 Man. Fish. Sci., No. 4, 154 pp. Hall, N.G. & Brown, R.S. (1995) Delay - difference models for the western rock lobster (Panulirus cygnus) fishery of Western Australia. ICES Mar. Sci. Symp., 199, 399410. Hancock, D.A. (1981) Research for management of the rock lobster fishery of Western Australia. Proc. Guy Carib. Fish. Inst., 33, 207-29. Joll, L.M. & Phillips, B.F. (1984) Natural diet and growth of juvenile western rock lobsters Panulirus cygnus George. J. Exp. Biol. Ecol., 75, 145-69. Lindner, B (1994) Long term management strategies for the western rock lobster fishery. Economic efficiency of alternative input and output based management systems, Vol. 2. Fisheries Dept Western Australia, Fisheries Management Paper No. 68, 36 pp. Marec Pty Ltd (1994) Long term management strategies for the western rock lobster fishery. A market-based economic assessment for the western rock lobster industry, Vol. 3. Fisheries Dept of Western Australia, Fisheries Management Paper No. 69, 71 pp. Meany, T.F. (1981) The Western Australian Rock Lobster Fishery. A Report of an Economic Survey, Fish. Rep. 33. Economic Analysis Section, Fisheries Division, Dept of Primary Industry, Canberra, Australia, 84 pp. Melville-Smith, R., Chubb, C.F., Caputi, N., Cheng, Y.W., Christianopolous, D. & Rossbach, M. (1998) Fishery independent survey of the breeding stock and migration of the western rock lobster (Panulirus cygnus). FRDC Project 96/108, 47 pp. Monaghan, P.J. (1 989) Distribution and marketing of Western Australian rock lobster. Fisheries Dept of Western Australia Management Report No. 29, 125 pp. Morgan, G.R. (1972) Fecundity in the western rock lobster Panulirus longipes cygnus (George) (Crustacea: Decapoda: Palinuridae). Aust. J. Mar. Freshwat. Res., 23, 13341. Morgan, G.R. (1974) Aspects of the population dynamics of the western rock lobster Panulirus cygnus George 11. Seasonal changes in catchability coefficient. Aust. J. Mar. Freshwat. Res., 25, 249-59. Morgan, G.R. (1979) Trap response and the measurement of effort in the fishery for the western rock lobster. Rapp. P-v Reun. Cons. Int. Explor. Mer., 175, 197-203. Morgan, G.R. (1980) Population dynamics and management of the western rock lobster fishery. Mar. Policy, 4, 5240. Morgan, G.R. & Barker, E.H. (1974) The western rock lobster fishing 1972-1973. West. Aust. Dept. Fish. Wildl. Rep., 15, 22 pp. ~

356 Spiny Lobsters: Fisheries and Culture Morgan, G.R., Phillips, B.F. & Joll, L.M.(1982) Stock and recruitment relationships in Panulirus cygnus the commercial rock (spiny) lobster of Western Australia. Fish. Bull., 80(3), 475-86. Norton, P.N. (1981) The amateur fishery for the western rock lobster. Dept Fish. Wildl. West Aust. Rep., No. 46, 108 pp. Pearce, A.F. (1989) The Leeuwin Current and the rock lobster. In Workshop on Rock Lobster Ecology and Management (Ed. by B.F. Phillips). CSIRO Marine Laboratories Rep. No. 207, 29 PP. Pearce, A.F. & Phillips, B.F. (1988) ENS0 events, the Leeuwin Current and larval recruitment of the western rock lobster. J. Cons. Int. Explor. Mer, 45, 13-21. Phillips, B.F. (1981) The circulation of the southeastern Indian Ocean and the planktonic life of the western rock lobster. Oceanogr. Mar. Biol., 19, 11-39. Phillips, B.F. & Brown, R.S. (1989) The West Australian rock lobster fishery : research for management. In Marine Invertebrate Fisheries : Their Assessment and Management (Ed. by J.F. Caddy), pp. 159-8 1. Wiley, New York, USA. Phillips, B.F., Brown, P.A., Rimmer, D.W. & Reid, D.D. (1979) Distribution and dispersal of the phyllosoma larvae of the western rock lobster Panulirus cygnus, in the southeastern Indian Ocean. Aust. J. Mar. Freshwat. Res., 30, 773-83. Walters, C., Hall, N., Brown, R.S. & Chubb, C.F. (1993). A spatial model for the population dynamics and exploitation of the Western Australia rock lobster, Panulirus cygnus . Can. J. Fish. Aquat. Sci., 50, 165CL62.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 19

Predicting the Catch of Spiny Lobster Fisheries B.F. PHILLIPS

Curtin University of Technology, P . 0 . Box U1987, Perth. Western

Australia 6845, Australia

R.CRUZ

Centro de Investigaciones Marinas, culle 16 144 entre Avu. leva y 3 era. Miramnr

Playa, Ciudad de la Habana, Cuba

N. CAPUTI and R.S. BROWN

Bermrd Bowen Fisheries Research Institute. Western

Australian Marine Research Laboratories, P.O. Box 20, North Beach, Western Australia 6020,Australia 19.1

Introduction

The prediction of future catches is a desirable objective for both lobster fisheries managers and fishermen, to assist management in preventing overfishing, and to assist fishers in forecasting monetary and industry requirements (e.g. marketing, purchase of new equipment). To predict successfully the size of the lobster catch requires accurate catch and effort data, and careful research on relationships between life-history stages. A knowledge of population size, level of breeding stock, level of larval settlement, growth and mortality rates of juveniles to recruitment, abundance of recruits to the fishery, the eventual contribution to the breeding stock from these recruits and environmental effects at different life-history stages is also very desirable. However, such data are available for few species. The assessment of most lobster fisheries is based mainly on advice resulting from analysis of catch/ effort data, and management is usually by restrictions on the lobster size, fishing effort (usually a closed season), and the taking of berried females. In many cases, the catch data from the commercial fishery may be reasonably accurate. However, the measure of effort in the fishery may be of dubious quality and the catch taken by amateur fishermen is often unknown. This chapter examines the present state of the catch prediction systems for Punulirus cygnus in Western Australia and Panulirus ornatus in Torres Strait (Australia), and outlines similar developments in New Zealand for Jusus edwardsii. The plan for the prediction system for catches of the Cuban fishery for Punulirus urgus is described, including some details of the Cuban fishery and the problems of measuring effort in the fishery.

19.2

Western Australia

The western rock (spiny) lobster, P . cygnus, is currently the only spiny lobster species for which adequate data exist for accurate catch predictions several years in advance. 357

358 Spiny Lobsters: Fisheries and Culture The western rock lobster supports one of the world’s largest rock lobster fisheries and is the most valuable single-species fishery in Australia, accounting for approximately 20-25% of the country’s gross income from the export of fisheries products (see Chapter 1). Panulirus cygnus occurs in Western Australia from North West Cape (21’44%) to just south of Cape Leeuwin (34’24’S), while the fishery is concentrated between Kalbarri (27’43’s) and Mandurah (32”30’S), a distance of 560 km. The 596 boats licensed for the fishery in 1998/99 operate 65 800 pots (lobster traps) and take an average catch of around 10 700 t (over the past 18 years) during a 7.5 month season (15 November-30 June) with a record catch of 13 600 t being achieved in 1998/99. Since 1963, the fishery has been subjected to limited entry (Hancock, 1981) with the objectives of optimal utilization of the resource, reasonable economic return to fishermen, and orderly exploitation to minimize conflicts among professional fishermen and between professional and recreational fishermen. The major regulations that support this management regime are a minimum size of 77 mm (November-January) and 76 mm (February-June) carapace length (CL), escape gaps in each pot, return of undersize and mature and egg-bearing (berried) females to the sea, closed seasons and restrictions on pot numbers and pot design (Phillips & Brown, 1989; Brown, 1992). Data on the levels of larval settlement of P . cygnus have been recorded at Seven Mile Beach since 1968 and at Jurien Bay since 1969 by catching the puerulus stage on collectors composed of artificial seaweed (Phillips, 1972). The period of settlement varies from year to year but the peak settlement occurs between September and January. The index of annual settlement in P . cygnus is calculated as the mean number of puerulus per collector from May of one year to April of the next (Pearce & Phillips, 1988). Information on commercial catches of the western rock lobster fishery was taken from monthly catch returns, which are completed by all fishermen as a condition of their licences, and from the landing returns of the processing companies. Accurate catch data are available from 1964.

19.2.1

Predictions

The predictions of the recruitment to the fishery and the catch have been made since the early 1970s based on the indices of abundance of puerulus settlement. These predictions were initially based on the relationship between the puerulus settlement and the index of recruitment during November-December 4 years later (Morgan et al., 1982). Later, Phillips (1986) related the puerulus index to the recruitment and the total catch 4 years later, since the variation in recruitment during the migratory phase of the fishery in November-January strongly influences the total catch of the year: about 45% of the annual catch is taken during this period.

Predicting the Catch of Spiny Lobster Fisheries

359

Separate predictions are now determined for the two parts of the fishery: the migratory phase (November-January; this phase is locally referred to as the ‘whites’ fishery because the migrating lobsters are a paler colour) and the non-migratory phase (February-June). Moulting occurs at the start of each of these phases and lobsters reaching legal size at these times become new recruits to the fishery. By examining these two phases of the fishery separately, Caputi et al. (1995a) have shown that the recruits first reach legal size in significant quantities after the moult in February just over 3 years after puerulus settlement, and most of the remainder would probably reach legal size by the start of the following season in November. Thus, a combination of the puerulus settlements 3 and 4 years before provides a better predictor of total catch than just the puerulus settlement 4 years before (Fig. 19.1). The following relationship was fitted using a logarithmic transformation and linear regression:

+

LCATCH, = 15.142 0.229 LPUERULUS,-3,,-4

+

uI,

where LCATCH is the log-transformed catch in year t , LPUERULUS is the logtransformed puerulus index 3 and 4 years prior, and u, is the error term. This

NORTH COASTAL (ZONE B) : CATCH - PUERULUS (Blg Bank excluded)

(Mllllon Potllfts

Million Potlifts

5.01

I 4.5 :

.P

4.0 :

3 3.5:

--E

- 79(3.6)

9 3.0:

5

- nomlnal)

2.5 : 473(3.4) *72(3.3) 01

t

1.5

0

30

60

00

99 98

n

t

90

120

150

Puerulus (Dongara) - 3,4 Years before

T

180

Fig. 19.1 Catch-puerulus relationship for the north coastal management zone of the Panulirus cygnus fishery in Western Australia. The year of the catch is shown with the nominal fishery effort (million pot lifts) in parentheses. Puerulus is number per collector per year. The three curves indicate the relationship at three levels of fishing effort (3.5,4.0and 4.5 million pot lifts). Adapted from Caputi et al. (1997).

360 Spiny Lobsters: Fisheries and Culture relationship has an R2 of 0.76 and residual mean square (RMS) of 0.0066 for the 18 years of catch data to 1990/91. The Durbin-Watson statistic of 1.24 indicates a positive autocorrelation in the residuals. This can be incorporated into the above relationship by time-series analysis using transfer function modelling (Henstridge, 1982; Noakes et al., 1987). The addition of an autoregressive term and a moving average term: u, = pu+l

+ e l and u, = pel-l

+ el,

respectively, was examined, where e, is an independently normally distributed error term. This resulted in an R2 of 0.79 (RMS = 0.0061) and R2 of 0.87 (RMS = 0.0039), respectively, indicating that the first-order moving average term provided a better fit to the data. This resulted in the following fit:

+

LCATCH, = 15.109 0.237 LPUERULUS,-3,r-4 u, = 0.998e1-1

+

+ el

Predictions can also be further assessed based on catch rate of juveniles below legal size obtained from a monitoring programme conducted on board commercial fishing vessels (Caputi & Brown, 1986). This programme started in 1971. This index of juvenile abundance has subsequently been revised by determining the abundances (i.e. catch rate) of appropriate size classes in the two parts of the fishery, NovemberJanuary and February-June, which are likely to be reflected in the legal-size catch of the fishery in the following year (Caputi et al., 1995b). These relationships take into account the increase in the number of escape gaps required on pots which first started in the 1986/87 season. The additional escape gaps caused a 40-60% decrease in the catch rate of undersize lobsters, and combined with better handling of the undersize which are caught in the pots and returned to sea, should result in a small increase in the subsequent catch owing to increased survival and growth (Brown & Caputi, 1986). The indices of abundance of the puerulus and juveniles have also been combined in a multiple regression relationship in order to obtain an improved predictor of the catch (Caputi et al., 1988, 1995b). These relationships have multiple correlation coefficients in the order of 0.9 and have provided more accurate predictions of catches than either the puerulus or juvenile data alone. The puerulus and juvenile indices complement each other. The puerulus index provides a long-term indication, up to 4 years, of the likely trends in catch, while the juvenile index provides a more accurate prediction of the catch, 1 year ahead. The puerulus programme was expanded in 1985 to obtain .a better understanding of the variation in settlement along the coast (Phillips et al., 1'991).This programme, combined with a study of the comparative growth between regions, will provide a better understanding of the variation in recruitment to the fishery between the different regions. These data are now being used to make catch predictions for the

Predicting the Catch of Spiny Lobster Fisheries

361

three management zones of the fishery, including taking into account the effect of fishing effort (Caputi et al., 199513, 1997). The areas of research currently being undertaken which will impact on the prediction of catches and the use of predictions involves: (1) the effect of increased fishing power on the catch rates of rock lobsters and on the fishing effort; (2) environmental effects, such as swell and water temperature, on the catchability of rock lobsters; (3) spatial variation in puerulus settlement; (4)variation in growth between regions and possible effect of density dependence; and (5) modelling of the life history and the impact of fishing. An assessment of the changes in fishing power occurring in the fishery since the early 1970s indicates marked improvements in boat construction, engine capacity and technology (such as radar and satellite navigation systems), as well as an increase in the amount of bait being used (Brown et al., 1995; Fernandez et al., 1998). While these innovations are aimed at obtaining a greater share of the catch, they also result in an overall increase in effective fishing effort. Environmental effects, such as ocean swell and water temperature, are known to affect the catchability of both the juvenile and the legal-sized catch. A preliminary assessment with only a few years of data indicates that the height of swell and water temperature are positively related to the catch after taking into account the puerulus/ juvenile abundances. While this information does not assist in the prediction of the catches, it helps to explain the reasons for any differences between predicted and actual catches. The development of computer models on the life history of the rock lobster is also contributing to the prediction system and the ways in which the prediction system may be utilized. Walters et al. (1993) have developed a comprehensive model of the whole life history and the impact of fishing which enables a range of possible management changes to be investigated. The life-history model is currently being developed for the key regions of the fishery. The prediction of spiny lobster catches of the western rock lobster has to date been based on information on puerulus settlement and juvenile densities or a combination of both. In addition, the results of the study of Phillips & Pearce (1989) suggest that, in the absence of such data, it might be possible to use other information such as sea level, or even the southern oscillation index (SOI), to perform a similar, but less accurate, function.

19.2.2

Use of catch predictions

These predictions of catch using the puerulus and juvenile indices have proved of immense value to both fisheries managers and fishers. The ability to forecast recruitment accurately allows improved financial planning by fishers and the processing companies. Information on prediction is regularly sought by the fishing industry before major investment decisions are made.

362 Spiny Lobsters: Fisheries and Culture However, in the long term, a more important use for predictions is that it enables the fisheries manager to be proactive in fisheries management rather than reactive to, for example, a major reduction in recruitment. Fisheries managers and fishermen use these predictions in their consideration of management options in response to fluctuations in recruitment before fishing operates on a year class, rather than having to wait for fishing to commence. For example, when a low recruitment was expected in 1986/87 management measures (reducing pot numbers) were taken from the beginning of the 1986/87 season to ensure that the breeding stock was not placed in jeopardy (Phillips & Brown, 1989; Brown, 1992; Caputi et al., Chapter 18). Fisheries managers are currently considering using these predictions to reduce year-to-year fluctuations in catch. This can be achieved by reducing fishing effort in years when high catches are predicted and allowing a flowover of catch in subsequent years when lower catches may be predicted. This approach to fisheries management recognizes that optimal fisheries strategies need to take into account the effect of variability in catches as well as trying to optimize the overall mean catch. The fishing industry may prefer to trade-off a small reduction in the overall mean catch if it is associated with a smaller variation in catch. This would also result in a greater stability in price, as prices may be depressed during periods of large catches and some markets may not be able to be supplied during periods of low catches. Because the catch forecasts in this fishery are now recognized as reasonably sound, the relative efficacy of introducing variable input or output control in accordance with the catch forecast should be investigated.

19.3

New Zealand

New Zealand has three species of rock lobster. The most important species is the red rock lobster J . edwardsii, which is found all around New Zealand and at some offshore islands, and it makes up more than 99% of commercial landings. The commercial fishery has been a limited-entry fishery since 1980. About 600 vessels take an annual rock lobster catch of around 3000 t. Rock lobsters are mainly caught by commercial pot fishermen. Until 1990, there were no restrictions on either the total catch or the number of pots. Since 1990, an individual transferable quota (ITQ) management system has been introduced. Other management measures include a minimum legal size (based on tail width) and protection of egg-bearing females. The commercial catch has been fairly stable since 1960, except for large landings from early fishing at the Chatham Islands. The effort required to take the catch, however, increased steadily until the early 1990s. Analysis of fishery and biological data indicated that the resource was under heavy fishing pressure (Annala & Breen, 1989), but rebuilding has since taken place, at least in the northern and central parts (Annala & Sullivan, 1998).

Predicting the Catch of Spiny Lobster Fisheries

363

The Booth crevice collector (Booth & Tarring, 1986) was specifically designed to catch pueruli of J. edwardsii. The design was stimulated by the observation that large numbers of puerulus settled naturally under stones in depressions and holes (including pholad shafts) along the shore at Castlepoint on the North Island (Booth, 1979). Breen & Booth (1989) found significant correlations of 0.76 (n = 7 ) and 0.82 (n = 6) between the levels of puerulus settlement of J . edwardsii at Stewart Island and the densities of juveniles in this area, aged 2 and 3 years, respectively, since settlement. Juvenile densities were based on the number caught in annual diver collections at a number of reefs. There are similar results from Wellington (Booth et al., 1999) Analyses of 13 years of data indicate good correlations between levels of puerulus settlement, juvenile abundance and recruitment to the fishery in Otago, an area in which the legal size for lobsters is less than elsewhere in New Zealand, and where lobsters recruit at 4-5 years of age (J. Booth, pers. comm.). Further north, there is close accord between settlement trends and fishery catch per unit effort (CPUE), 5-7 years later (Booth et al., 1999), with the currently high CPUE probably reflecting high settlement in 1991/92.

19.4

Cuba

Cuba is the main producer of the spiny lobster P . argus and one of the principal lobster-exporting countries of the world. This fishery reached its maximum level during the 1980s, with record catches occurring in the fishing seasons of 1984/85 (12 748 t) and 1985/86 (14 092 t). Catches over 1992-1996 averaged 9364 t, resulting in exports worth about US $100 million per year. The catch in the fishery is taken with approximately 250 vessels, 1300 fishermen and 300 000 fishing gear units (see Chapter 7). The principal regulations governing the fishery are based on the strict enforcement of limited entry, fishing gear restrictions in each of several zones, a minimum legal size of 69 mm CL, a closed season of 90 days (March-May) and prohibition on taking ovigerous females. Strict control is also exercised on the number of boats and boat replacement (Cruz et al., 1991b). The catches in the zones vary considerably but all declined in the late 1980s, although the catches in the Gulf of Batabano fell in 1990 after being relatively stable at about 7000 t for a number of years (Fig. 19.2). The two zones on the south side of Cuba currently produce 80% of the total catch, with the Gulf of Batabano producing about 60%. A detailed data-gathering system on the spiny lobster fishery has been established. Each enterprise provides monthly information on the number of boats fishing, the gear fished and the catches made by each boat. In addition, the scientists and technician in biology collect data from the catch on size composition, sex ratio, stage

364 Spiny Lobsters: Fisheries and Culture 3500 I

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Fig. 19.2 Annual total catch of Panulirus argus in Cuba from 1962 to 1996 in the four fishing grounds. Note differing vertical scales. After Cruz (1999).

of reproductive development of females, etc. All of these data are then compiled in a computer system (Sotomayor & Cruz, 1990) for management and research purposes.

19.4.1

Catch and effort

A major problem in predicting the annual catch is the wide variation in the total catch over the past 20 years (see Chapter 7). Cruz et al. (1991b) examined the variations in the catch and the regulations concerning fishing seasons, and found that from 1965 to 1977, with a closed season of 45 days, and the presence in the catch of 18% of sublegal lobsters, a 9000 t average catch was produced, which included a high proportion of newly recruited lobsters. An extension of the closed season to 90 days (March-May) and a stricter observance of the minimum legal size after 1978 reduced the sublegal catch to 6% and resulted in an increase in the mean length at capture, and there was an increase in the average annual catch of about 3000 t. This increase was also partly due to the increasing use of pesqueros (Chapter 22) over this period. It would also appear that some of the fluctuations in the annual catches could be induced by environmental conditions, including heavy rainfall, that can affect the catchability of legal-sized lobsters or the levels of recruitment (Cruz et al., 1986a, 1991a). The problem of measuring effort in the fishery is complex since the lobsters are captured by a range of gears and techniques in a two-season fishery. A major feature of the fishery has been the introduction of the pesquero: 71 % of the catch is obtained using this technique in the season from June to September (summer season). During

Predicting the Catch of Spiny Lobster Fisheries

365

the mass migration period the main fishing device used is the fishing gear jauldn (trap-like net) which accounts for 55% of the landings during October to February (autumn-winter season). The main methods in use today are: pesqueros, which are lifted and checked by the fishermen, with the aid of a net placed around the pesqueros, and sometimes with bully nets. Using this gear, the fishermen take 71% and 28% of the total catch in summer and autumn-winter, respectively jauldns, rectangular traps joined by nets (usually 10 units in each long rope), are set principally during the mass migration. This gear accounts for 55% of the total catch in autumn-winter and only 9% during June to September nasa, unbaited traps, take between 11 and 12% of the total catch in summer and autumn-winter, respectively bully nets used in natural shelters take about 4-7% of the total catch in summer and autumn-winter, respectively Old car tyres, which are set as refuges and checked by the fishermen in some areas, take about 1-2% of the total catch. The catches and effort of the different gear types from 1980-1995 are presented in Fig. 19.3. Because of the range of fishing gear used at different times during the development of the fishery, it is not possible to have a single measure of effort. However, about 80-83% of the catch is now taken by either the pesqueros or jauldns in the two fishing seasons. It might therefore be possible to use estimates of the fishing effort index that were standardized to pesquero effort in the first season and jauldns in the second season (Cruz et al., 1993), in this case the total catch for each season being divided by CPUE (catch/number of gear checked by the fisherman). Puga er al. (1996) have shown that the fishing mortality is related to the number of pesqueros checked and the catchability is higher for the 3- and 4-year-old lobsters. For the season of mass migration, fishing mortality is related to the number of jauldns checked and the catchability is higher for the age groups 4 and 5. The results proved that higher proportions of young lobsters are caught in thepesqueros and the catchability tends to be constant, while in the juuldn it is more variable owing to the differential vulnerability to gear because of the mesh size (the smallest can escape while the larger cannot). The variation in total annual catch taken by the pesquero and juuldn is high because it depends on the variability in the vulnerability of the lobsters to the different fishing gears between years. Between 57% and 97% of the catch variation can be explained by the variation in catchability of the lobsters to the pesquero and jauldn, respectively (Cruz, et ul., 1994). The fishery showed a marked reduction in catch in 1990, due to a reduction in recruitment in a period of intense fisheries exploitation (Puga et ul., 1991; Cruz el al., 1995a), probably associated with the effect of Hurricane Gilbert in September 1998. Mooers & Maul (1996) reported that the hurricane caused profound mixed layer deepening of 30-35 m, with surface cooling of 3 and 4°C and strong upwelling and

366 Spiny Lobsters: Fisheries and Culture

6000 r

5000

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-

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-

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PESQUERO

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1000 -

o

l

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!

l

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~

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80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95

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YEARS

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YEARS

Fig. 19.3 Seasonal catch and standardized effort data on the principal gears, in the Punulirus argus fishery in the Cuban archipelago.

down-welling; however, the effects of wind stress on the oceanic circulation, phyllosoma larval drift and the metamorphosis of puerulus are some of the many unanswered questions about such tropical storms. The impact of the storm along the coast caused considerable disruption to the bottom and may have affected recruitment in the nursery areas (R. Cruz, unpubl. data). With the level of recruitment in 1988-1996, catches have been fluctuating around 9870 t on the Cuban shelf. Since 1990, the use of jaulbns has been confined to the period from 15 September to 15 January, and the closed season extended to 4 months in 1991, 1992 and 1993. It was also decided not to increase the total number of fishing gears, including pesqueros, in order to stabilize the fishing effort. It is important that the relationships between catch and effort in the Cuban spiny lobster fishery continue to be investigated, to determine the reasons for the fluctuations in the catch, and it is also essential that research into the mode of operation of the pesqueros is undertaken in order to increase confidence in the predictive system.

r

~

Predicting the Catch of Spiny Lobster Fisheries 19.4.2

361

Recruitment and predictions

Indices of abundance of puerulus, juveniles and pre-recruits were used to determine relationships between the main events in the life-history stage and subsequent recruitment to the fishery. Cuba installed a similar type of collector to that used to catch the puerulus stage of P . cygnus (Phillips, 1972), to catch the puerulus of P . argus (Cruz et al., 1991a). Collectors were placed at four sites in the Gulf of Batabano, one zone in the southeast and two zones in the north-east (Fig. 19.4) were checked monthly after each new moon from 1988. The catches on these collectors have been extremely satisfactory and there were variations in the pattern of settlement between these sites (Fig. 19.5). It would appear that when the level of puerulus recruitment was high it occurred at stations Hicacos and Matias and towards of the end of the settlement season. In contrast, the magnitude of larval recruitment in stations Cantiles and Diego Perez was lower than in the other locations. The south-eastern and north-eastern regions receive fewer pueruli than the Gulf of Batabano. The settlement of pueruli on the 6

iiotopo distribulionnvl*,..L’”~

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0 Coral reef +yq

Channel

Fig. 19.4 Map of Cuba showing the fishing grounds for Panulirus argus and the locations from which the indices of puerulus settlement, juvenile and pre-recruit abundance were obtained. Puerulus settlement: (1) Matias, (2) Hicacos, (3) Cantiles, (4)Diego Perez, (5) Boca Rica, (6) North Cruz del Padre, (7) North Cay0 Verde. Juveniles: (8) nursery area of Bocas de Alonso. Pre-recruits: (9) coast of Coloma, (10) North Juan Garcia, (11) North COCO,(12) Cay0 Dios.

368 Spiny Lobsters: Fisheries and Culture HICACOS

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collectors on the Cuban coast followed a very similar seasonal pattern at all locations studied, with maximum settlement occurring from September to December (Cruz et al., 1991a; Cruz, 1999). In Cuba, the juvenile data, as part of the predictive system, are obtained from monthly monitoring of artificial concrete block reefs designed by Cruz et al. (198613) and placed at a nursery area in the south-east of the Isle of Juventud from 1982. The annual index was calculated as the mean number caught per block per month. The seasonal cycle of juveniles (16-50 mm CL) shows a period of maximum recruitment between June and September. In the western region of the Gulf of Batabanb, size distributions of pre-recruits, based on the number of lobster below the minimum legal size (69 mm, CL), were obtained from monthly monitoring of commercial catch from the artificial shelters known as pesqueros (Chapter 22), starting in 1983. The annual index of pre-recruits to the fishery was calculated as the average number of undersize lobsters per pesquero per month. The seasonal pattern was similar in all 1 1

Predicting the Catch of Spiny Lobster Fisheries

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years (1984-1 994), with the maximum abundance of pre-recruits occurring between March and May. There was a strong relationships between the juvenile and pre-recruit indices, with correlation of r = 0.93, p < 0.001 (Cruz et al., 1995a). This suggests that variation in the pre-recruit index could be caused by the estimates of juveniles. Moreover, the pre-recruit index from 1983/84 to 1988/89 was larger than that obtained from 1989/ 90 to 1992/93; hence this system may contribute to the predictive system. Figure 19.6 illustrates the timing between the different recruitment phases of P . argus in the Cuban archipelago. The integration of the most recent results allows an update of the complex life cycle (Cruz, 1999). Using an estimated larval life of 7 months, it was estimated that individuals recruit to the fishery at an average of 2 years and 1 month (25 months) and to the fishing gear at about 2 years and 3 months (27 months, in June or at beginning of the season) (Cruz, 1999). Phillips et al. (1992) estimated that both sexes enter the fishery at 69 mm (CL) at 2 years and 3 months, which is similar to estimates based on length-frequency data by Cruz et al. (1991a) of 2 years and 1 month. In the Gulf of Batabano, the cross-correlation between monthly settlement and catch indicates that there is a weaker and negative correlation 27 months later (r = -0.36) and a significant correlation 32 months later (r = 0.56), coinciding with the group of 3-year-old lobsters, which is the most widely represented group in the landings (Puga et al., 1995, 1996). A method of catch prediction is being developed based on the index of juvenile abundance and their relationship with lobster catches in the next year. The first commercial catches predictions were made in 1992 (r2 = 0 . 6 9 , ~< 0.001, n = 10) in the Gulf of Batabano (Cruz et al., 1995a). Later, Cruz et al. (1995b) and Cruz (1999), using a regression of total catch against the juvenile index for 1982 to 1992, and the abundance of juveniles in 1993, predicted that the total catch in 1994 would be 5400 t. The catch was 5517 t. Based on the data for 1982-1994 and the level of juveniles in 1995, it was predicted that the total catch in 1996 would be 5407 t. The catch was 5332 t (r2 = 0.77, p < 0.001, n = 14). Nevertheless, other factors such as

J A I O N D J F Y A Y J J I ~ O N D

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310 Spiny Lobsters: Fisheries and Culture

environmental conditions, fishing period and fishing effort (Caputi & Brown, 1986), which may affect these relationships, have not been taken into account at this stage. An integrated series of data to determine their effect will be required. A model to predict the catch based solely on indices of puerulus settlement can provide up to 2 years’ early prediction, given the short data series (6 years, 1989/91 to 1994/96), and is effective only when the larval level of recruitment is very low. Catches by the fishery are still very variable, and hence it is necessary to have at least 10 years of data on indices of puerulus settlement and subsequent catches to provide a preliminary assessment, and about 15 years of data will be essential before researchers can have real confidence in the predictions.

19.5

Discussion

Recruitment of the spiny lobsters into the commercial fisheries represents the final stage of a series of life-history phases lasting for several years. There are two distinct phases of interest: (1) the larval phase and the factors responsible for variations in the level of puerulus settlement, and (2) the pre-recruit phase, linking settlement and recruitment to the fishery. (1) The mechanisms contributing to the level of puerulus settlement need to be understood. Studies of P. cygnus have clearly shown the involvement of the ocean environment in the recruitment process. Pearce & Phillips (1988) examined annual mean values of the SOI, Fremantle sea level and other environmental conditions off Western Australia and the annual puerulus settlement index for P. cygnus. Their analyses showed a clear correlation of the annual levels of larval settlement with the strength of the major current flowing down the coast of Western Australia, the Leeuwin Current, as measured by the annual mean sea level. The strength of this current is affected by El Niiio Southern Oscillation (ENSO) events. Recently, the variation in puerulus settlement has also been shown to be influenced by the strength and frequency of winterlspring storms that affect onshore movement of surface waters (Caputi & Brown, 1993; Caputi et al., 199%). The frequency of onshore winds during late winter and spring also affected the abundance of puerulus settlement of J. edwardsii in New Zealand (Booth, 1989). Correlations between ENSO events and catches of rock lobster fisheries have also been recently demonstrated between Jasus novaehollandiae ( = J. edwardsii in Tasmania and New Zealand) (Harris et al., 1988). Harris et al. (1988) suggested the implication of wind-driven transport in the larval recruitment processes of these and other Jasus spp. distributed around the Southern Ocean. Pollock (1992) also believes that a similar mechanism is responsible for larval transport in all Jams spp., but he emphasizes the effect of large-scale eddies and subgyres within the overall anticlockwise circulations of the three ocean basins adjacent to the Southern Ocean. In either case, the dispersal and recruitment of the Jasus spp. would appear to be very different from that of P. cignus. It seems that different species of spiny

Predicting the Catch of Spiny Lobster Fisheries

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lobsters have different mechanisms of larval recruitment. These mechanisms, depending on a variety of oceanic processes, are significantly affected by oceanographic events. All of these studies indicated that environmental factors acting on the larval stages are probably responsible for much of the variation in lobster catches. However, although there is a clear link between ocean climate and larval recruitment, the mechanisms that act on the larval or puerulus stage to bring this about are unknown. Pearce & Phillips (1 988) suggested that stronger current flows might provide increased stimulus for metamorphosis of late-stage phyllosomata to the puerulus stage, or perhaps increased mixing of shelf and offshore waters. Both of these hypothesis were recently examined by sampling programmes to examine the distributions of the phyllosomata and pueruli, and the physical environment, within and adjacent to sections through the Leeuwin Current off Western Australia. Sampling was concentrated on the area beyond the continental shelf. Shelf and offshelf waters are essentially separate and since the puerulus apparently swims across the shelf to settle in the coastal reefs, the mechanisms determining the number of puerulus available to settle almost certainly operate in this area. McWilliam & Phillips (1997) have hypothesized that it is the amount of food available to the latestage phyllosoma larvae which determines the number of larvae successfully resulting in the puerulus stage. They suggested that when the current is strong there is more mixing, which creates more food and therefore more larvae metamorphosing to the puerulus stage, resulting in a higher level of settlement. (2) The prediction of recruitment to a fishery needs to be based on the demonstration that the commercial catch in any year is highly correlated with the level of settlement of the puerulus phase of the lobster, and/or the abundance during the juvenile phase, prior to recruitment to the fishery. This still requires confirmation in New Zealand. In Cuba, a system to sample and estimate the abundance of juvenile P. argus has led to the development of a successful forecast of the catch 1 year in advance. This holds promise for advising industry and fishermen about future changes in catch and for matching catch to the likely level of effort required. Data will continue to be collected to test the robustness of the catch forecast and to extend it to other regions. If synchronous moulting occurs in a fishery, then dividing the catch into these moult phases may increase our understanding of the timing between the puerulus settlement and recruitment to the fishery (Caputi et al., 1995b). In addition, if growth is greatly different between regions of the fishery there will be a regional difference in the period between puerulus and recruitment. The expansion of the number of puerulus settlement collector sites in Western Australia and Cuba is not only assisting in the understanding of the variation in recruitment to the fishery between the different sectors of the fishery, but will also help in the understanding the effect of environmental factors and spawning stock on the level of puerulus settlement.

372 Spiny Lobsters: Fisheries and Culture

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Fig. 19.7 Annual catch of the Cuban fishery for Panulirus argus and the Western Australian fishery for Panulirus cygnus.

Current research on the New Zealand and Cuban spiny lobster fisheries is aimed at a better understanding of the relationships between these life-history stages. The possibility that density-dependent mechanisms are operating during the juvenile phase is evident from the curved relationship between puerulus and catch, with a stronger density-dependent impact evident in the high abundance region of the Abrolhos Islands, compared with the relatively low abundance in the south coastal region (Caputi et al., 1995b, 1997). However, the evidence to date suggests that the principal determinant of the level of recruitment is the level of puerulus settlement (Phillips, 1986). It is of interest that the variations in the catch of the Cuban spiny lobster fishery are of similar size to those in the rock lobster fishery in Western Australia (Fig. 19.7). In Western Australia, the fluctuations in the catch of P . cygnus are believed to reflect annual variations in recruitment to the catchable stock (Phillips, 1986), which is to be expected under conditions of high effort (Morgan, 1980; Phillips & Brown, 1989). The current areas of research in the Western Australian fishery will provide information on the effect of increases in fishing efficiency on estimates of indices of abundance of juveniles and recruitment and effective fishing effort. The environmental effects on catchability may help to explain some of the differences between predicted and actual catches, while the modelling of the fishery will enable the predictions to be better utilized by management.

References Annala, J.H. 8c Breen, P.A. (1989) Yield and egg-per-recruit analysis for the New Zealand rock lobster, Jaws edwardsii. N . Z . J. Mar. Freshwat. Res., 23, 93-105. Annala, J.H. & Sullivan, K.J. (1998) Report from the Mid-Year Fishery Assessment Plenary, November 1998: stock assessments and yield estimates. Unpublished report held in NIWA Greta Point Library, Wellington, New Zealand, 44 pp. Booth, J.D. (1979) Settlement of the rock lobster, Jusus edwardsii (Decapoda: Palinuridae), at Castlepoint, New Zealand. N.Z. J. Mar. Freshwnt. Res., 13, 395-406.

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Booth, J.D. (1989) Occurrence of the puerulus stage of the rock lobster Jasus edwardsii at the New Plymouth Power Station, New Zealand. N . Z . J . Mar. Freshwat. Res., 23, 43-50. Booth, J.D. & Tarring, S.C. (1986) Settlement of the red rock lobster, Jasus edwardsii, near Gisborne, New Zealand. N.Z. J . Mar. Freshwat. Res., 20, 291-7. Booth, J.D., Foreman, J.S., Stotter, D.R., Branford, E., Renwick, J. & Chiswell, S.M. (1999) Recruitment of the red rock lobster, Jasus edwardsii, with management implications. N Z . Fisheries Assessment Research Document, No. 99/10, 102 pp. Breen, P.A. & Booth, J.D. (1989) Puerulus and juvenile abundance in the rock lobster, Jasus edwardsii at Stewart Island. N.Z. J. Mar. Freshwat. Res., 23, 529-33. Brown, R.S. (1992) A decade of research and management for the western rock lobster (Panulirus cygnus) of Western Australia. Proceedings of International Workshop on Lobster Ecology and Fisheries, 12-15 June 1990, Havana, Cuba. Rev. Inv. Mar., 19(1-3), 204-22. Brown, R.S. & Caputi, N. (1986) Conservation of recruitment of the western rock lobster (Panulirus cygnus) by improving survival and growth of undersize rock lobster captured and returned by fishermen to the sea. Can. J . Fish. Aquat. Sci., 48, 2236-42. Brown, R.S., Caputi, N. & Barker, E.H. (1995) A preliminary assessment of the effect of increases if fishing power on stock assessment and fishing effort of the western rock lobster (Panulirus cygnus George 1962) fishery in Western Australia. Crustaceana, 68, 227-37. Caputi, N. & Brown, R.S. (1986) Prediction of recruitment in the western rock lobster (Panulirus cygnus) fishery based on indices of juvenile abundance. Can. J . Fish. Aquat. Sci., 43, 2131-9. Caputi, N. & Brown, R.S. (1993) The effect of the environment on the environment on the puerulus settlement of the western rock lobster (Panulirus cygnus) in Western Australia. Fish. Oceanogr., 2, 1-10,

Caputi, N., Brown, R.S. & Phillips, B.F. (1988) Forecasting rock lobster catches - check and double check. FINS, 21, 18-22. Caputi, N., Brown, R.S. & Chubb, C.F. (1995a) Regional prediction of the western rock lobster (Panulirus cygnus) catch in Western Australia. Crustaceana, 68, 245-56. Caputi, N., Brown, R.S. & Phillips, B.F. (1995b) Prediction of catches of the western rock lobster (Panulirus cygnus) based on indices of puerulus and juvenile abundance. ICES Mar. Sci. Symp., 199, 287-93. Caputi, N., Chubb, C.F. & Brown, R.S. (199%) Relationship between spawning stock, environment, recruitment and fishing effort for the western rock lobster, PanuZirus cygnus, fishery in Western Australia. Crustaceana, 68, 2 13-26. Caputi, N., Chubb, C.F., Hall, N. & Pearce, A. (1997) Relationships between life history stages of the western rock lobster, Panulirus cygnus, and their implications for management. In Developing and Sustaining World Fisheries Resources: The State of Science and Management (Ed. by D.A. Hancock, D.C. Smith, A. Grant & J.P. Beaumer), pp. 579-85. Second World Fisheries Congress, Brisbane, Australia. Cruz, R. (1999): Variabilidad del reclutamiento y pronostico de la pesqueria de langosta (Panulirus argus, Latreille, 1804) en Cuba. Tesis presentada en opcibn del grado cientifico de Doctor en Ciencias Biologicas. Ciudad de la Habana, CIM/UH, Cuba, 99 pp. Cruz, R., Brito, R, Diaz, E. & Lalana, R. (1986a) Ecologia de la langosta (Panulirus argus) al Sz de la isla de la Juvenitud. I. Colonizacion de arrecifes artificiales. Rev. Invest. Mar. (Cuba), 7(3), 3-17. Cruz, R., Brito, R., Diaz, E. & Lalana, R. (1986b). Ecologia de la langosta ( P . argus) a1 se de la Isla de la Inventud. 11. Patrones de Movimiento. Rev. Invest. Mar. (Cuba), 7(3), 19-35. Cruz, R., Leon, M.E. de, Diaz, E., Brito, R. & Puga, R. (1991a) Reclutamiento de puerulus de langosta (Panulirus argus) a la plataforma Cubana. Taller Internacional sobre Ecologia y Pesqueria de Langosta, Ciudad Habana, Cuba, 12-16 Junio de 1990. Rev. Invest. Mar., 12(1-3), 6675.

314 Spiny Lobsters: Fisheries and Culture Cruz, R., Leon, M.E. de & Puga, R. (1995a) Prediction of commercial catches of the spiny lobster Panulirus argus in the Gulf of Batabanb, Cuba. Crustaceana, 68, 238-44. Cruz, R., Leon, M.E. de, & Puga, R. (1995b) Pronbstico de la captura de langosta (Panulirus argus) por regiones de pesca, Cuba. Rev. Cub. Invest. Pesq., 19(1), 51-8. Cruz, R., Puga, R. & Leon, M.E. de (1993) Fluctuaciones de las capturas de langosta (Panulirus argus) en 10s refugios artificiales. Regibn del Golfo de Batabanb, Cuba. In Memorias del Taller Binacional Mkxico-Cuba sobre la utilizacidn ak refugios artificiales en las pesquerias de langosta: sus implicaciones en la dinamica y manejo del recurso, 17-21 mayo de 1993 (Ed. by J.M. Gonzalez & R. Cruz). Isla Mujeres, Q.R., Mexico. Cruz, R., Puga, R. & Lebn, M.E. de (1994) Aspectos de la dinamica de poblaciones de la langosta espinosa (Panulirus argus) en Cuba. Cambios en el coeficiente de capturabilidad. Rev. Cub. Invest. Pesq. lS(l), 6-9. Cruz, R., Sotomayor, R, Lebn, M.E. de & Puga, R. (1991b) Impact0 en el manejo de la pesqueria de langosta (Panulirus argus) en el archipielago cubano. Taller Internacional sobre Ecologia y Pesqueria de Langosta. La Habana, Cuba, 12-16 Junio de 1990. Rev. Invest. Mar., 12(1-3), 246-53. Fernandez, J., Cross, J. & Caputi, N. (1998) The impact of technology on fishing power in the western rock lobster (Panulirus cygnus) fishery. In Proceedings of International Congress on Modelling and Simulation (MODSIM 9 ) , Vol. 4 (Ed. by A.D. McDonald & A. NcAleer), pp. 1605-10. The Modelling and Simulation Society of Australia Inc., Canberra, Australia. Hancock, D.A. (1981) Research for management of the rock lobster fishery of Western Australia. Proc. Gulf Carib. Fish. Inst., 33, 207-29. Harris, G.P., Davies, P., Nunez, M. & Meyers, G. (1988) Interannual variability in climate and fisheries in Tasmania. Mature, 333, 754-7. Henstridge, J.D. (1982) TSAr An Interactive Package for Time Series Analysis. Numerical Algorithms Group, Oxford, UK, 165 pp. McWilliam, P.S. & Phillips, B. F. (1997) Metamorphosis of the final phyllosoma and secondary lecithotrophy in the puerulus of Panulirus cygnus George: a review. Mar. Freshwat. Res., 48, 783-90. Moaers, C.N.K. & Maul, G.A. (1996) Global coastal ocean volume. Revised and submitted to Sea Intra-Americas Sea Circulation, 8 Nov. 1996, pp. 1-56. Morgan, G.R. (1980) Increases in fishing effort in a limited entry fishery - the western rock lobster fishery 1963-1976. J. Cons. Int. Explor. Mer., 39, 82-7. Morgan, G.R., Phillips, B.F. & Joll, L.M. (1982) Stock and recruitment relationships in Panulirus cygnus, the commercial rock (spiny) lobster of Western Australia. Fish. Bull., 80(3), 475-86. Noakes, D., Welch, D.W. & Stocker, M. (1987) A time series approach to stock-recruitment analysis: transfer function noise modeling. Mat. Res. Modeling, 2(2), 2 13-33. Pearce, A.F. & Phillips, B.F. (1988) ENS0 events, the Leeuwin Current, and larval recruitment of the western rock lobster. J. Cons. Int. Explor. Mer, 45, 13-21. Phillips, B.F. (1972) A semi-quantitative collector of the puerulus larvae of the western rock lobster Panulirus cygnus George (Decapoda: Palinuridae). Crustaceana, 22, 147-54. Phillips, B.F. (1986) Prediction of commercial catches of the western rock lobster Panulirus cygnus George. Can. J. Fish. Aquat. Sci., 43, 2126-30. Phillips, B.F. & Brown, R.S. (1989) The Western Australian rock lobster fishery: research for management. In Marine Invertebrate Fisheries: Their Assessment and Management (Ed. by J.F. Caddy), pp. 159-82. Wiley and Sons, New York, USA. Phillips, B.F. & Pearce, A.F. (1989) Long-term variability of pelagic fish populations and their environment. In Proceedings of the International Symposium on the Long-Term Variability of Pelagic Fish Populations and their Environment, Sendai, Japan: 14-18 November 1989 (Ed. by T. Kanasaki, S. Tanaka, Y. Toba & A. Taniguchi), pp. 33945. Pergamon Press, Oxford, UK.

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Phillips, B.F., Palmer, M.J., Cruz, R. & Trendall, J.T. (1992) Estimating growth of the spiny lobsters Panulirus cygnus, Panulirus argus and Panulirus ornatus. Aust. J . Mar. Freshwat. Res., 43, 1177-88. Phillips, B.F., Pearce, A.F. & Litchfield, R.T. (1991) The Leeuwin Current and larval recruitment to the rock (spiny) lobster fishery off Western Australia. J. R. SOC. West. Aust., 74, 93-100. Pollock, D.E. (1992) Palaeoceanography and Speciation in the Spiny Lobster Genus Panulirus in the Indo-Pacific. Bull. Mar. Sci.,51(2), 13546. Puga, R., Leon, M.E. de & Cruz, R. (1991). Evaluacibn de la pesqueria de langosta espinosa Panulirus argus. Rev. Invest. Mar., 12(1-3), 28692. Puga, R., Leon, M.E. de & Cruz, R. (1995) Estado de explotacibn y estructura poblacional de la langosta Panulirus argus en Cuba. Rev. Cub. Invest. Pesq., 19(2), 41-9. Puga, R., Leon, M.E. de & Cruz, R. (1996) Catchability for the main fishing methods in the Cuban fishery of the spiny lobster Panulirus argus (Latreille, 1804), and implications for management (Decapoda, Palinuridae). Crustaceana, 69, 703-18. Sotomayor, R. & Cruz, R. (1991) Sistema automatizado de direccion para la investigacion y el manejo de la pesqueria de langosta en Cuba. Taller Internacional sobre Ecologia y Pesqueria de Langosta. La Habana, Cuba, 12-16 Junio, 1990 [Abstract], Rev. Invest. Mar., 12(1-3). Walters, C. (1993) A spatial model for the population dynamics and exploitation of the Western Australian rock lobster, Panulirus cygnus. Can. J . Fish. Aquat. Sci., 50, 1650-2.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 20

Bioeconomic Modelling of the New Zealand Fishery for Red Rock Lobsters (Jasus edwardsiz') P.A. BREEN and D.J. GILBERT

National Institute of Water and Atmospheric

Research, P.O.Box 14-901, Kilbirnie, Wellington 6003. New Zealand

K. CHANT New

Zealand Ministry of Economic Development, P . 0 . Box 1473. Wellington

6001. New Zealand

20.1

Introduction

This paper describes work carried out in 1992 to address what was perceived then as substantial overfishing of the main New Zealand stock (NSI) of red rock lobsters, Jams edwardsii (Breen, 1991; Booth & Breen, 1994). At that time, biomass was estimated to be about half that which would support deterministic maximum sustainable yield (MSY), and effort levels were about twice those that would produce MSY. More recent stock assessments have been conducted on smaller units of the NSI stock (e.g. Breen & Kendrick, 1997a, b; Starr et al., 1999). These indicated that some units of the stock are relatively healthy and they experienced recent quota increases as a result. Conversely, the southern part of the fishery has just experienced a quota decrease resulting from a pessimistic assessment (Starr et al., 1999) combined with a decision rule (Starr et al., 1997). The authors believe that the present chapter retains its general applicability to the stressed parts of the stock. If the fishery could obtain more revenue by taking a greater sustainable catch from a rebuilt stock, and could do so at less cost by expending less fishing effort, then economic return would be greater than it is now. Although the advantages of having a rebuilt fishery seem obvious, rebuilding the stock requires that catches be reduced for some period. Catch reductions would cause a further degradation of economic performance during the rebuilding period. In other words, possible future benefits can be obtained only at some immediate cost. Users legitimately ask whether the benefits from rebuilding outweigh those costs. This question is not simple. The stock could be rebuilt in many ways. One extreme would be to close the fishery for a relatively short period, then reopening when the stock had rebuilt. Another extreme would be to reduce catches slightly for a long period, to rebuild the stock slowly. In between, there is an infinity of possible strategies. 376

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A further complication is caused by the unpredictable variation common to all fisheries. For any proposed management action, the possible response of the stock varies, although the limits of probable variation can be estimated (see Fig. 6 in Booth & Breen, 1994). So the economic performance of a rebuilding strategy cannot be predicted with certainty; only a range of possibilities can be estimated. In this chapter, some of these issues are examined with respect to the NSI stock of red rock lobsters in New Zealand. The economic consequences of various quota management options were explored using a simple age-structured model. Population dynamics of the stock were simulated from estimates of growth and natural mortality rates and from an estimate of the 1987 position of the stock, using both deterministic and stochastic (with randomly varying recruitment) versions of the model. An initial economic description of the fishery was obtained from real data. A simple economic model described how revenue varies with the catch, how costs vary with fishing mortality, how capital is invested and how it depreciates; then estimated economic surplus from the fishery. The time series of economic surpluses were compared by using net present values (NPVs).

20.2

Methods

.Full details of the procedures used are given by Breen et al. (1992).

20.2.1

Biological model

The biological model contained one pre-recruited (less than legal size) and 15 recruited cohorts for each of five areas around the North and South Islands. Growth was incorporated through von Bertalanffy equations for males and females for each area. These growth parameters, also used by Annala & Breen (1989), were estimated from a variety of studies. In the model, to was manipulated so that lobsters were just above the legal size when they entered the second cohort in the model. The model calculated biomass from the length-weight relations of Saila et al. (1979). To initialize the model populations’ initial age structures, the fishery was assumed to have been at equilibrium with a constant total catch and constant area-specific instantaneous fishing mortality rates ( F ) for the period 1980-1982, a period when landings, effort and catch rates varied little (Breen, 1989). Fishing mortality for females was assumed to be half that for males (Annala & Breen, 1989) because females carrying eggs cannot be retained legally by the fishery. Mean catch for that period was 4193 t, and fishing mortality rate for males was assumed to be F = 0.80 for three model areas and F = 0.64 for the remaining two areas, based on mortality estimates of Annala (1979; 1980). Catches from each model area were calculated as a constant proportion of the total catch, equal to 1986 proportions (Sanders, 1988).

378 Spiny Lobsters: Fisheries and Culture Recruitment at the initial equilibrium was assumed to be constant. For each area, the model calculated the recruitment that produced the equilibrium catch at the assumed equilibrium value of F. Ricker’s (1975) version of the catch equation was used in the fishing portion of the model. The model’s control variable was annual catch. For a specified total allowable commercial catch (TACC), the model determined area catches, then used iterative estimation to determine the fishing mortality rate required to take the specified catch from each area. F was not permitted to exceed 1.50, so catches in some circumstances could be less than the TACC. Natural mortality rate was assumed to be M = 0.10 (Annala & Breen, 1989). Each year, numbers of individuals in all but the first cohorts for each area were calculated from the cohort abundance in the previous year. In the deterministic version of the model, recruitment remained constant at the initial equilibrium value. In the stochastic version, the model simulated log-normal recruitment with mean equal to initial equilibrium recruitment for each subpopulation and variance based on the observed variation in CPUE for 1979-1986 for each subpopulation. Neither model incorporated a stock-recruit function. After initializing to simulate the assumed equilibrium situation in 1980-1 982, the model was run for 4 model years to simulate the fishery from 1983 to 1987, using the real catch data from those years (Breen, 1989). At the end of this process, the model populations were in a non-equilibrium state that simulated the stock after fishing in 1987.

20.2.2

Economic model

The economic model also used the five area subpopulations used by the biological model. Each year for each area, the model calculated the catch in several size classes corresponding to commercial grades. Gross revenue was calculated from the catch and the grade prices, which were obtained in confidence from the industry. Economic surplus was calculated as gross revenue minus all costs. Costs were assumed to depend on fishing mortality rate and the value of capital invested in the fishery. The former (variable costs) include fuel, bait, wages, etc., and were assumed to vary in direct proportion with fishing mortality rate. Costs related to the value of capital investment (capital costs) were assumed to include depreciation, insurance and the opportunity cost of capital. Opportunity cost of capital was calculated as for ordinary annuities, using an interest rate of 10% and amortization period of 10 years. Depreciation of capital was assumed to occur at a constant fixed rate of 12%, based on data described below. It was assumed that the potential fishing mortality rate that could be generated was directly proportional to capital investment in the fishery. It was also assumed that if capital investment fell below the level required to produce the fishing mortality needed to take the specified catch, then sufficient new capital would be

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invested in the fishery. So the level of capital investment each year was determined either by depreciation, resulting in a still-adequate investment, or by new investment. The simple economic surplus each year was the sum, for each area, of the gross revenue minus the various costs. The model was run to a 25-year time horizon with specified TACCs. The economic surplus time series were compared by calculating NPVs, using a discount rate of 10%. Two economic constants were required for each area: the relation between fishing mortality and cost, and the relation between capital investment and potential fishing mortality rate. To initialize the model the capital investment for the first year was also required. Data were obtained from New Zealand Department of Statistics surveys of rock lobster fishermen for 1987/88. Costs were then apportioned into the variable and capital costs discussed above. There appeared to be no economic surplus for the financial year examined. Revenue for 1987 was estimated from the 1987 catch and landed price, then a zero economic surplus was assumed for 1987 and the variable and capital costs were estimated: together they equalled revenue, and their relative proportion could be estimated from the statistical data. Once capital costs had been estimated, capital investment could be estimated. Finally, the two required constants for each area were estimated from the estimates of variable cost, effort, investment and F for each area.

20.2.3

Examining management strategies

‘Strategies’ - patterns of TACC assigned over time - were defined in terms of three elements: (1) an initial TACC (usually low enough to allow stock biomass to increase); (2) a length of time for which the initial TACC remained in effect; and (3) a final TACC in effect to the end of the 25-year model run. This three-element definition was more tractable (and more realistic politically) than a continuously varying TACC. A constant TACC for 25 years is a special case, where elements (1) and (3) are the same. With the deterministic model, only one run of 25 model years was made for each management strategy examined. With the stochastic model, 100 runs of 25 years each were made with each specified management strategy in order to examine the effect of recruitment variability.

20.3 20.3.1

Results Deterministic model

Results from a single deterministic run made as an example are shown in Fig. 20.1. Biomass increased while the TACC was 3000 t (Fig. 20.la); after 5 years it could

380 Spiny Lobsters: Fisheries and Culture 20000

Catch

80

V

V

Y

- 0.2

5 million

I

60 -

40 -

20 -

0

87

(b)

88

89

QO

81

92

83

94

96

Model Year

86

Q7

88

QQ

4 100

Fig. 20.1 (a) Example from the deterministic model showing predicted catch, stock size and fishing mortality rate Ffor the initialization period through 1987, then an additional 13 years. The TACC was set at 3000 t for 5 years, then increased to 4000 t. (b) Predicted economic variables from the same 13 years of model runs shown in (a). Note the change in x-axis scale.

support a 40004 catch indefinitely. Fishing mortality rate (one area is shown) decreased during the first 5 years of constant TACC as the biomass increased, increased slightly to accommodate the increased TACC, then decreased steadily as stock biomass increased. Continuing with the same example, gross revenue was closely related to catch (Fig. 20.lb), remaining nearly constant during each period of constant TACC. A slight decrease was caused by the changing population structure: reduced fishing mortality resulted in larger numbers of larger individuals, which sell for a lower price. Capital value declined at the depreciation rate until year 8 (Fig. 20.lb), after which it was determined by the required fishing mortality. Capital costs are directly proportional to the capital value, and are not shown. Variable costs are directly proportional to fishing mortality rate (Fig. 20.la).

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In this example, simple economic surplus was slightly negative in the first year, then increased steadily. As the population increased the required fishing mortality rate decreased, so variable costs decreased. The required capital value decreased steadily, so opportunity and depreciation costs also declined. Revenue increased when the TACC was increased. Thus, surplus increased during the period shown. The estimated NPV resulting from the time series of surpluses in this example was NZ $286 million; annual surpluses from the rebuilt fishery were N Z $49 million. This example suggests that a large economic benefit could be realized by rebuilding the stock. Finding a strategy that maximizes NPV in the deterministic model is not straightforward. As a first approach, Fig. 20.2 shows the consequences of imposing a constant TACC indefinitely. NPV increased with increasing constant TACC to a maximum near 3400 t; at higher TACCs, NPV decreased rapidly to zero at the deterministic present sustainable yield of 3950 t. More complex strategies were then examined. The three-element strategy described above can be collapsed to two variables, because for any combination of initial and final TACC it is possible to find (empirically) the ‘rebuild time’ that maximizes NPV. (Lower initial TACCs allow the stock to increase at a higher rate, so NPV is maximized with a shorter rebuilding time for lower initial TACCs.) NPV was maximized in the model when fishing was stopped completely for 2 years and then a TACC of 4300 t imposed (Fig. 20.3). However, the NPV was nearly as high for less drastic strategies, e.g. 3000 t for 7 years followed by 4300 t. Finally, the negative economic surplus in the first year is shown as a function of initial TACC in Fig. 20.4. There was no initial TACC that returned an economic surplus in the first year. The minimum deficit occurred with a TACC of 3400 t; both higher and lower TACCs caused greater deficits.

NPV

(S millions)

300

1000

2000

3000

4000

constant TACC

Fig. 20.2 Net present value of the 25-year series of economic surplus from the deterministic model, plotted as a function of a single constant TACC.

382 Spiny Lobsters: Fisheries and Culture

3001 2000

0

1000

2000

Initial quota

3000

4000

Fig. 20.3 Contour plot of the response surface of net present value as a function of initial and final TACCs, using for each combination the optimum rebuilding time. The contour interval is NZ $10 million. These results were obtained from the deterministic model.

20.3.2

Stochastic model

Stochastic economic predictions became dramatically more uncertain as the TACC increased (Fig. 20.5). Variability was small for TACCs less than 3000 t, but at larger TACCs the 5th and 95th percentiles diverged rapidly. With a constant TACC of

-16' 1000

2000

3000

4000

TACC

Fig. 20.4 Negative surplus or deficit from the deterministic model, predicted for the first year after a TACC is imposed, as a function of the first-year TACC.

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Fig. 20.5 Summary of stochastic results. The bold line shows net present value as a function of a constant TACC as in Fig. 20.2. The lower, centre and upper lines are the 5% percentile, median, and 95% percentile, respectively of 100 runs of the stochastic model at each constant

TACC.

3500 t, NPV ranged from NZ $53.5 to 306.4 million. At higher TACCs, some large negative NPVs appeared but are not shown because under such conditions, other financial responses not modelled here would probably remove capital investment from the fishery.

20.4

Discussion

Several firm conclusions can be drawn. First, rebuilding an overfished stock would be highly profitable to New Zealand, despite short-term losses. There appeared to be no economic surplus in 1987 and the fishery was overcapitalized. In the short term, reductions in catch would cause reduced revenues while capital investment continued to incur costs; the result is a negative economic surplus. However, under most rebuilding strategies the economic deficit would persist for only 1-2 years. The NPVs of many rebuilding strategies were in the order of NZ $250 million. Second, stochastic variation in recruitment had no effect on median economic expectation, but greatly affected the range of possible results. At low TACCs most economic results were close to the deterministic result. At higher TACCs, economic performance of the fishery varied widely with recruitment (Fig. 20.5). For a manager attempting to obtain a good series of economic surpluses from the fishery, the deterministic prediction would become increasingly irrelevant with increasing TACCs. The manager might want to define the acceptable risk of obtaining a result at some defined level of risk, then using the stochastic approach shown in Fig. 20.5 to determine the highest TACC within the defined risk.

384 Spiny Lobsters: Fisheries and Culture Only the sensitivity to variation in recruitment was described above. Before using this approach, the manager would need to know how sensitive the conclusions were to variation in other variables and to uncertainties around estimates. It is important to define the economic goal of management carefully. NPV is a useful index for making comparisons, but the economic goal should probably not simply maximize NPV. The greatest NPV was obtained by setting catches to zero for 2 years; this is unlikely to be acceptable. It would cause a large initial deficit (Fig. 20.4) persisting for 2 years; the real economic, political and social implications are not captured in NPV. First-year losses are only a crude way to examine other effects; a better approach would be to define and model them explicitly. Individual enterprises vary widely in their investment, overall efficiency and response to changing conditions, so more detailed economic modelling must predict a range of human behaviour. A manager attempting to decide on a TACC strategy would have to consider at least four effects of the strategy: the likely NPV, the uncertainty associated with that estimate, the depth of short-term economic hardship, and the risk of further stock declines. There is probably no objective way to find the most acceptable strategy. The approach described here provides a tool for exploring the possible responses from particular strategies. Introduction of the rock lobster fishery into New Zealand’s system of management by individual transferable quotas, at about the time this article was written, has resulted in structural change within the fishery. The value of 1 t of quota is much higher than the value of 1 t of lobsters, reflecting the perception that quota represents a future stream of profits. This perception has led to greater willingness to accept short-term pain for long-term gain. When faced with inevitable quota reductions in a badly depleted part of the stock in 1993, the Gisborne fishers developed an unusual package that allowed the stock to rebuild and fishers to maintain economic viability (Breen & Kendrick, 1997a). In such systems, so long as appropriate biological safeguards are maintained, fishers may be the best judges of appropriate economic risk in the face of uncertainty.

Acknowledgements We thank Alex Duncan, Roger Falloon and Drs Robert Deacon and Raymond Clarke for comments on early versions of this project, and Ian Doonan and Chris Francis for comments on the manuscript.

References Annala, J.H. (1979) Mortality estimates for the New Zealand rock lobster, Jusus edwurdsii. Fish. Bull., 77. 471-80.

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Annala, J.H. (1980) Mortality estimates for the rock lobster, Jasus edwardsii, near Gisborne, New Zealand. N.Z. J . Mar. Freshwat. Res., 14, 357-71. Annala, J.H. & Breen, P.A. (1989) Yield- and egg-per-recruit analyses for the New Zealand rock lobster, Jams edwardsii. N.Z. J . Mar. Freshwar. Res., 23, 93-105. Booth, J.D. & Breen, P.A. (1994) The New Zealand fishery for Jasus edwardsii and J. verreauxi. In Spiny Lobster Management (Ed. by B.F. Phillips, J.S. Cobb & J. Kittaka), pp. 64-75. Blackwell Scientific, Oxford, UK. Breen, P.A. (1989) Rock lobster stock assessment 1989. N.Z. Fish. Assess. Res. Doc. 89/6, 35 pp. Breen, P.A. (1991) Assessment of the red rock lobster (Jasus edwardsii) North and South Island stock, November 1991. N . Z . Fish. Assess. Res. Doc. 99/16, 36 pp. Breen, P.A., & Kendrick, T.H. (1997a) A fisheries management success story: the Gisborne, New Zealand, rock lobster fishery. Mar. Freshwat. Res., 48(8), 1103-10. Breen, P.A., & Kendrick, T.H. (1997b) Production analyses for two substocks of the New Zealand red rock lobster (Jasus edwardsii) fishery. N.Z. Fish. Assess. Res. Doc. 97/4, 26 pp. Breen, P.A., Gilbert, D.J. & Chant, K. (1992) A bioeconomic analysis of the red rock lobster (Jasus edwardsii) NSI stock. N.Z. Fish. Assess. Res. Doc. 9211, 21 pp. Ricker, W.E. (1975) Computation and interpretation of biological statistics of fish populations. Bull. Fish. Res. Bd. Can., 191, xvii + 382 pp. Saila, S.B., Annala, J.H., McKoy, J.L. & Booth, J.D. (1979) Application of yield models to the New Zealand rock lobster fishery. N . Z . J . Mar. Freshwat. Res., 13, 1-1 1 . Sanders, B. (1988) The 1986 New Zealand rock lobster landings. N . Z . Fish. Data Rep., 32, 31 pp. Starr, P.J., Bentley, N. & Maunder, M.N. (1999) Assessment of the NSN and NSS stocks of red rock lobster (Jasus edwardsii) for 1998. N . Z . Fish. Assess. Res. Doc. 99/34, 45 pp. Starr, P.J., Breen, P.A., Hilborn, R. & Kendrick, T.H. 1997. Evaluation of a management decision rule for a New Zealand rock lobster substock. Mar. Freshwar. Res., 48(8), 1093-101.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 21

Modelling for Management: The Western Rock Lobster Fishery N.G. HALL and R.S. BROWN Bernard Bowen Fisheries Reseurch Institute, Western Ausiralian Marine Reseurch Laboraiories, P.O. Box 20, North Beach, Western Australia 6020, Australia

21.1

Introduction

Because of its importance to Western Australia, the fishery for western rock lobster, Panufirus cygnus, has been the subject of considerable research (Hancock, 1981; Phillips & Brown, 1989; Brown, 1991) and is actively managed on the basis of the results of the research. It is Australia’s largest single-species fishery, with a commercial value of approximately Aus $250 million per year. Of fundamental concern to the managers of this fishery is the need to ensure that levels of exploitation will not result in recruitment overfishing. Consequently, management strategies have sought to contain increases in effective effort and increase the survival of pre-recruits (Brown & Caputi, 1986). These measures ensure that the breeding stock is maintained at, or above, historical levels, which have provided adequate recruitment. Concern has been heightened by the current high level of exploitation (Phillips & Brown, 1989) and the potential for technological innovation to increase effective effort further and potentially, therefore, reduce the size of the breeding stock. The current level of egg production is estimated to have recovered from approximately 15-25% of that of the original unfished stock (Walters et af., 1993) to approximately 25-30%. The size at maturity of females lies well above the minimum legal size of 76 mm carapace length (CL) over much of the geographical range of the fishery. Only in the waters around the Abrolhos Islands do female rock lobsters attain maturity at lengths below the minimum size. Thus, if effective effort continues to increase, the fishery has the potential to reduce further the abundance of females reaching maturity. Modelling the dynamics of the western rock lobster fishery has been an essential element of the research programmes for this species. The structures of the models used have been determined by the level of research understanding available, the availability of data and the requirement to provide advice to the managers. Management strategies adopted for the fishery have therefore been strongly influenced by the assessments resulting from these models. This chapter aims to examine the history of model development for the western rock lobster fishery and to relate that development to management needs and 386

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actions. The structure imposed on current models through the requirements of managers and the characteristics of the fishery will also be discussed.

21.2

Introduction of limited entry

Following a very rapid increase in the number of pots (lobster traps) used in the P . cygnus fishery, without a corresponding increase in catch (Fig. 21.1), the Western Australian government limited the number of boats operating and the number of pots per boat from March, 1963 (Bowen, 1980). This action created a select group of licence holders with a vested interest in the management of the fishery, and imposed a requirement for an annual review of management strategies. This requirement has ensured that data are continuously collected and analysed to provide thorough and regular assessments of the state of the fishery.

21.3

Initial yield estimates and the introduction of escape gaps

The declining catch rates observed in some fishing areas in the early 1960s raised concern among fishery managers and scientists that a detailed assessment of the rock lobster stock was urgently required. This was undertaken by Bowen & Chittleborough (1966), who developed the first model to describe the P . cygnus fishery. By using the decline in monthly catch rates from the heavily exploited Abrolhos Islands, they estimated natural mortality, fishing mortality, annual exploitation rate and annual recruitment. A similar trend of seasonal catch rates was noted in all fishing areas; thus, the conclusions drawn from the study were applied to the entire fishery. This suggested that the annual rate of exploitation had 10 3

*.

*

59/60 *62/63 a

61162 58/59 -60/61

0

0

2

4

6

8

1 0 1 2 1 4

Nominal effort (million pot lifts)

Fig. 21.1 Annual catch and nominal effort for the period 1952/53 to 1962/63.Data presented by Phillips & Brown, 1989.

388 Spiny Lobsters: Fisheries and Culture risen sharply from 1944/45 to the early 1960% where it then levelled off, with approximately 60% of all lobsters larger than the minimum legal size being caught each fishing season. Bowen & Chittleborough (1966) concluded that the standing stock had declined to 16 million kg from the original unfished stock of 64 million kg of legal sized rock lobsters. They assessed the sustainable yield from the fishery to be 7.3 f 0.9 million kg, assuming that recruitment and effort were stabilized. Reduced recruitment was attributed to mortality of sublegal sized rock lobsters and a recommendation was made that escape gaps be introduced into all pots. Inclusion of a 50-mm wide escape gap became mandatory in 1966, and the gap was subsequently increased in 1972 to 54 mm (Hancock, 1981). From the 1986/87 fishing season, the number of escape gaps was increased to three (or four, depending on pot construction) gaps of 54 x 305 rnm (Brown & Caputi, 1986). Later, Morgan (1977) reviewed the method applied by Bowen & Chittleborough (1966). He concluded that their assumptions of constant catchability and no recruitment through the fishing season would result in inaccurate estimates.

21.4

Reduction in duration of fishing season

Despite limitations on vessels and trap numbers, the fishing effort in the fishery continued to increase. Concerned by this trend, fishery managers and industry requested the advice of scientists on the optimum level of fishing effort for the fishery. Morgan (1977) concluded from similarities in catch rates through the fishery that P . cygnus probably forms a single interbreeding stock. He noted, however, that some population parameters such as growth rates and size at first maturity varied in different areas of the fishery. He suggested that this variation might justify separation into a number of management regions. Morgan (1979) analysed the fishery using the Schaefer (1957) model, the generalized stock production model (Pella & Tomlinson, 1969; Fox, 1975), and a delayed recruitment model developed to study the Homarus americanus fishery by Marchesseault et al. (1976). Maximum yield was estimated to be 8-8.6 million kg, with an optimal level of fishing effort of 5.6-5.9 million effective pot lifts (Fig. 21.2). At that time, the effective effort recorded for the fishery was approximately 8 million pot lifts. Morgan (1977) also analysed the rock lobster data using a length-based cohort analysis (Pope, 1972; Jones, 1974) and a dynamic pool model of the form proposed by Ricker (1958), but later (Morgan, 1979) expressed the view that at that time there was ‘no species of rock lobster for which sufficient information is available on these aspects [recruitment, and density dependent growth and mortality] to enable a dynamic pool type of yield model to be applied with even a reasonable degree of confidence to estimate future total yields’. From the cohort analysis, Morgan (1977)

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Phillips and Brown (1989)

Hancock (1 981)

0

Morgan (1 979)

0

11

,

,

,

,

0

2

4

6

8

, , , 101214

Effective effort (million pot lifts)

Fig. 21.2 Annual catch and effective effort from 1944/45 to 1982/83, showing the Schaefer models fitted by Morgan (1979), Hancock (1981) and Phillips & Brown (1989). The data are presented in Phillips & Brown (1989).

concluded that the yield curve was almost asymptotic in shape and that increasing effort would bring about little, if any, decrease in yield. A similar result was obtained from the Ricker yield-per-recruit analysis. The results from this latter model also suggested that yield-per-recruit at the present levels of effort would not be improved by a change in minimum size. Complementing the assessment of yield per recruit, Morgan (1980) also examined the relationship between an index of abundance of the spawning stock and the resultant settlement of puerulus, using a Ricker (1958) stock-recruitment relationship. Although the model provided a good fit to the data, Morgan was conscious of the limitations of the data available (such as a time series representing a general decline in spawning stock over the period), and was aware of the potential bias resulting from environmental factors. While the magnitude of puerulus settlement appeared to be dependent on the abundance of the parent spawning stock, Morgan drew upon the earlier work of Chittleborough & Phillips (1975) to conclude that the assumption of constant recruitment to the exploited stock was realistic within the range of spawning stocks so far encountered. Accordingly, conclusions based on the yield-per-recruit analysis would be adequate in assessing total yield from the fishery. Morgan (1979) recommended that effort be reduced, as similar levels of catch could be achieved with reduced levels of effort. This advice was accepted and the duration of the fishing season was reduced by 6 weeks in 1977 (Morgan, 1979; Bowen, 1980). However, within 5 years the level of nominal effort had increased and was above the level recorded prior to the shortening of the season. Despite this, no further action has been taken regarding the length of the fishing season; effort limitations have taken other forms.

390 Spiny Lobsters: Fisheries and Culture 21.5

Reduction in pot quota

Research continued to improve the accuracy of the estimate of the optimum level of effort for the fishery. Expressing the logistic model in terms of the equilibrium value of annual mortality rate, Caddy (1986) refitted the Schaefer model to data from the western rock lobster fishery from 1954/55 to 1960/61, and 1967/68 to 1972/73. The estimate of maximum sustainable yield (MSY), 11.4 million kg, was considered by Caddy to be slightly high as a consequence of the missing data in his analysis. The value of MSY was achieved at an overall (whole of life) exploitation rate of 60%. Using data from 1944/45 to 1976/77, Fogarty & Murawski (1986) applied a delaydifferential model (Marchesseault et a/., 1976), and a delay-difference model (Deriso, 1980; Schnute, 1985) with a Ricker stock-recruitment function, to the western rock lobster fishery. The estimate of maximum equilibrium yield (MEY) obtained from the delay-differential model was 8.0 million kg at an effort of 5.8 million pot lifts, while the delay-difference model produced an estimate of maximum equilibrium yield of 8.8 million kg, with an effort of 6.3 million pot lifts producing a yield of 95% of the maximum equilibrium yield. Hancock (1981) refitted the Schaefer model to data to 1978/79, and Phillips & Brown (1989) included data to 1982/83 in a further reanalysis using the Schaefer model (Figure 21.2). Hancock’s analysis resulted in an estimate of MSY of 9.3 million kg with a fishing effort of 7.2 million pot lifts. The subsequent analysis by Phillips and Brown estimated MSY to be 9.8 million kg obtained with an effective effort of 8.2 million pot lifts, compared with the then current (1989) level of effective effort of about 10 million pot lifts. Advice to management resulting from these analyses (Hancock, 1981; Phillips & Brown, 1989) was that effort in the fishery might be reduced by as much as 30% without affecting long-term annual yield, and that this would be to the economic advantage of the fishing industry (Phillips & Brown, 1989). However, the effects of such a reduction on individual regions of the fishery were not considered. Morgan et al. (1982) continued to study the recruitment process, fitting a relationship of the Ricker form (Ricker, 1958) to the series of puerulus settlement indices and subsequent catch of rock lobsters during the period of annual migration, from November to December. They also refitted a Ricker relationship between an index of abundance of the spawning stock and subsequent puerulus settlement. While subsequent study suggested that the dome-shaped nature of the spawning stock to puerulus settlement relationship was probably an artefact of the data collection procedure (Phillips & Brown, 1989), the correlation between puerulus settlement and subsequent catch proved of great value in providing the basis of catch predictions for industry and management (Phillips, 1986). Fishery managers, industry and scientists saw the potential of these predictions of future recruitment to the fishery. Caputi & Brown (1986) and Caputi et al. (1995b) demonstrated that an improved prediction of recruitment to the fishery, and subsequent catch, might

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also be obtained using the abundance of sublegal sized rock lobsters or a combination of both sublegal sized rock lobsters and puerulus settlement indices. Within 5 years of the introduction of a reduced fishing season in 1977/78, fishing effort had increased to the level that preceded the reduction (Bowen & Hancock, 1989). The need to reduce effort was again being discussed by fisheries managers and the fishing industry. A prediction for 1986/87 of the lowest recruitment and catch to be experienced since 1973/74 provided the stimulus for action to be taken by the fishery’s managers. The decision was taken to reduce pot quotas temporarily in 1986/ 87 by 10%. A permanent pot reduction programme was also put in place for subsequent seasons, with the number of pots to be reduced by 2% per year (of the original 1985/86 level) from the 1987/88 season until the 1991/92 season when 90% of the original pot quota would be utilized (Hall & Brown, 1995).

21.6

Maintenance of breeding stock

It was recognized that the programme of pot reduction introduced in 1986/87 would not achieve a 10% reduction in ‘effective’ effort, as fishers would compensate by activating latent effort in the fishery. This would be achieved by lifting each pot on more days, by increasing mobility (allowing effort to be directed more rapidly to areas of higher catch rates), and by more careful positioning of pots on areas of rock lobster habitat. Through the period from 1986/87 to 1991/92, industry, research and management discussions were undertaken to consider future strategies for management of the fishery. Industry was concerned that additional restrictions might be imposed before an assessment was made of the benefits accruing from the new regulations (10% pot reductions, increases in the number of escape gaps and improved handling techniques for undersize lobsters). Hall & Brown (1995) re-examined the Schaefer and generalized production models, and delay-difference models of the fishery, in order to assess the increased survival of pre-recruits and the impact on yield from these management measures, including pot reductions and escape gap changes. The Schaefer model produced an estimate of MEY of 9 f 1 million kg with an effort of 9 million pot lifts, while the generalized production model produced a less precise estimate of MEY of 10.6 f 7 million kg at an extrapolated effort of 14 million pot lifts. It should be noted that the effective effort measure used in this calculation was based on a revised algorithm and results are not completely comparable with earlier results. Results from the delay-difference model were more optimistic, suggesting that an MEY greater than 12 million kg might be possible. This would be achieved, however, at an effort level considerably in excess of the current effort level. Such a conclusion is highly dependent on the very questionable assumption that recruitment would remain relatively independent of spawning stock at further reduced levels of spawning stock.

392 Spiny Lobsters: Fisheries and Culture While models used to describe rock lobster fishery dynamics inherit many of the features of the scalefish models from which they are derived (e.g. natural and fishing mortality, migration and stock-recruitment relationships), there are some notable differences, These differences are derived from the fact that growth in crustaceans occurs through a number of discrete moult steps, rather than as a continuous process. Age determination is not possible because a record, such as the annual growth checks laid down within scales, otoliths and fin rays of scalefish, is not available for crustaceans. Associated with the moult cycle are changes in activity and food consumption, which result in changes in the vulnerability of rock lobsters to baited pots. Models of rock lobster fisheries generally attempt to describe the dynamics of the population, rather than the individual rock lobster. While growth of an individual is stepwise in nature, the average growth of animals (of a particular size) in the population may be regarded as continuous if the time at which each moult occurs is not synchronized for all rock lobsters. Moulting activity for the western rock lobster does, however, peak at certain times of the year, and these periods correspond to times of more rapid growth for the population, for those categories of animals moulting at that time. There is a growing recognition that models applied to lobster fisheries should represent the growth process in a more realistic manner. Caddy (1977, 1979, 1987), Campbell (1985), Fogarty & Idoine (1988), Annala & Breen (1989) and others have extended the traditional models for scalefish to the study of crustaceans, by incorporating into models of yield per recruit and egg per recruit the processes of growth through moulting, and reproduction associated with the intermoult period. Recognizing that these processes characterize crustacean fisheries, Hall et af. (1990) applied a length-structured model to the western rock lobster fishery. This discrete, deterministic, simulation model reflected the effect of ecdysial growth on the recruitment process, catchability by baited traps, and the duration of the fishery for migratory animals (November-January). More recently, Hall & Brown (1991) applied a simple compartmental model to the rock lobster fishery. Recruitment to the fishery and catchability were modelled as seasonally varying functions, both related to the moult cycle. This continuous model calculated both the effort and resulting catch within each month, allowing the within-season effects of a number of closed season options to be evaluated. Among the proposals discussed by managers, industry and researchers were strategies that might redistribute fishing effort within each fishing season, which provided greater protection for spawning females and afforded protection for the larger mature rock lobsters. Advice regarding the effectiveness and impact of such strategies could not be provided from either the production models or the regression models linking stages of the life history. Biological parameters (e.g. growth, size at maturity), abundances of rock lobsters and exploitation rates differ between regions, and models were required to reflect these differences. Models were required that examined the impact within different management zones of within season changes in

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effort. Strategies affecting the level of effort on various sex and age classes were to be explored. Most existing models were not capable of providing such information. To address these requirements, a spatial model was developed for the western rock lobster fishery by Walters ef al. (1993). This length-structured model updated the system state at fortnightly time steps. Growth by moulting and synchronization of moulting (to simplify the real situation recorded in the field) were assumed. Biological parameters of growth and size at maturity used in the model differed between regions. Recruitment to the fishery was assumed to be of the Beverton-Holt form. Calculated values of recruitment were modulated by the observed deviations of puerulus settlement from their mean value, to reflect the annual variability imposed by environmental factors. Recruiting rock lobsters were distributed spatially over the range of the fishery. Migration occurred between the grid cells into which the fishery was divided. Within-season changes in vulnerability were allowed to vary, thus modifying the fishing mortality. Fishing effort was calculated by the model, and responded to the changing distribution and abundance of rock lobsters. Effectiveness of nominal fishing effort was increased from 1971 to 1992 at about 1% per year for shallow water (0-40 m) and at about 2.5% per year for deep water (>40m), to allow for increases in fishing efficiency due to improvements in boats, gear and fishing technology. The spatial model (Walters et al., 1993) was used to examine a wide range of strategies proposed by industry and management. These strategies included seasonal area closures, a maximum legal size, and reductions in pot quota for part of or the entire fishing period. The model predicted that reduction of the pot quota (i.e. the total number of pots that are used within the fishery) by 10% was likely to achieve only a 6% reduction in the effective effort (Fig. 21.3~).Long-term catch was expected to be reduced by only 0.5% (Fig. 21.3a), but egg production was increased by approximately 6% (Fig. 21.3b). The catch rate was expected to remain relatively unchanged (Fig. 21.3d), and the processors’ production of the most valuable ‘A’ grade (14&179 g tail weight) rock lobsters was expected to decline by 1% (Fig. 21.3e). Use of the Walters e f al. (1993) model enabled the managers of the fishery to identify clearly the major concern, that the breeding stock appeared to have been reduced to a level of between 15 and 25% of its original unfished level. Continued improvements in the technology utilized by the fleet suggested that effective effort would continue to increase, resulting in further erosion of egg production from the stock. As a consequence of this study, fishery managers decided that the limit reference point for the fishery should be set at 25% of the estimated egg production for the unfished stock, identifying this as the level of egg production and exploitation that existed in the fishery during the late 1970s to early 1980s. A strategy to achieve recovery of the breeding stock in each of the management zones of the fishery was introduced for the 1993/94 fishing season. The regulations that were imposed included a reduction of pot usage by l8%, a requirement to release mature female lobsters with visible setae, a maximum legal CL for retention

394 Spiny Lobsters: Fisheries and Culture

Fig. 21.3 Assessment of the impact of a 10% reduction in pot quota in 1991/92, compared with predictions from continued use of the current pot quota. The time series plotted are (a) annual catch (million kg) (b) egg production (billions of eggs), (c) effort (million pot lifts), (d) catch rate (kg per pot lift), and (e) proportion of catch by weight in each processing grade. The figure represents the standard form of output produced by the Walters et al. (1993) model.

of female lobsters (different sizes applying in the north and south of the fishery to reflect size composition within each area), and a 1-mm increase in the legal minimum CL for both sexes from November to January. The regulations were introduced at a time when short-term impact of the new regulations was likely to be offset by a strong recruitment predicted from puerulus settlement. The change in minimum size was intended to shift catch from the peak November-January period to later in the fishing season when prices were traditionally more favourable. A fisheryindependent survey of breeding stock was initiated to monitor the impact of the new regulations.

21.7

The current situation

Both fishery-dependent and independent observations from the fishery suggest that the 1993/94 management package has achieved the objective of increasing egg production to the level observed in the fishery during the early 1980s. With growing confidence that the breeding stock is now increasing, and that processes are in place to monitor and react to adverse trends in egg production, managers have turned

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their attention from sustainability towards achieving greater value from the available catch. Options are being explored to determine whether greater value can be achieved by utilizing the information available from forecasts of recruitment to reduce interannual variability in catches by appropriate adjustment to regulations, to reduce within-season variability in catch levels, to reduce the impact of the closed fishing season and to reduce costs of fishing. Forecasts of future recruitment are now available at a regional level (Caputi et al., 1995a). These predictions have been invaluable to fishers when considering investment decisions, and to processors when considering options for marketing product. While the predictions have been used by managers in considerations leading to the pot reductions in 1986/87 and subsequent seasons, in the advice resulting from fishery models, and in the timing of implementation of the 1993/94 management package, considerable opportunity exists for managers to use the available forecasts to improve the value of the fishery and the financial return to fishers. To provide the detailed advice needed for consideration of alternative management strategies, increasingly complex models are now required. Fundamental to these models is the need for a precise and accurate description of the growth of the lobsters within the different regions of the fishery. Individual variability in growth is a characteristic of lobster biology that must be assessed. A model of the growth of western rock lobsters, similar to that described by Punt et al. (1997), has been applied to tagging data for the western rock lobster, in order to estimate monthly transition matrices describing the probability of lobsters at each size growing to a new size class within the time step. Results from this study are consistent with available information on the moulting process and provide the basis for development of full length-structured models for the fishery. The model developed by Walters et al. (1993) has now been extended to a full length-based model structure, similar to that described by Bergh & Johnston (1992) and Punt & Kennedy (1997). Such models are necessary where advice is required on the likely change in size composition of catches or where controls such as minimum and maximum length are considered. For rock lobsters, where individual variability in growth is a feature of the biology, length-structured models accommodate the variability in growth explicitly through the use of transition matrices representing the probability of various growth increments. More recently, assessment of the impact of the 1993/94 management package has required analysis of the short-term response of egg production indices derived from the fishery-independent research surveys of breeding stock. The model that has been developed for this assessment estimates the fishing mortality decrease required to produce the observed response in egg production indices, and to produce the observations of discarded setose females, and female lobsters above the maximum size, recorded by fishers in their log books. Using this information, estimates have been produced of the impact of the various regulations within the management package. The major contribution to the increase in egg production has been associated with the regulation to protect setose lobsters. Effort reduction was of

396 Spiny Lobsters: Fisheries and Culture

slightly less importance in its contribution. The conclusion of the assessment is that the management package achieved its objective. Continued monitoring of breeding stock using the fishery-independent surveys should ensure that egg production is maintained at an appropriate level with respect to the limit reference point established by the fishery managers.

21.8

Discussion

Surplus production models have had a considerable influence on the early management of the western rock lobster fishery. Difficulty in obtaining information on growth, and other biological parameters, as a consequence of crustacean growth by ecdysis, has hampered the development of dynamic pool models. Therefore, advice given to managers and to industry has focused on the appropriate level of fishing effort to be used, on a total fishery basis. This limited advice is no longer sufficient for either managers or the fishing industry. There is a growing industry recognition that the western rock lobster stock is heavily exploited, and that technological advances, particularly global positioning systems (GPS), have the potential to reduce the breeding stock to a level that might impact upon future recruitment. There is also a general acceptance of the data showing that biological parameters vary through the spatial extent of the fishery, that recruitment to different sectors of the fishery varies and that exploitation rates in the sectors also vary. Management strategies such as size limitations, seasonal and area closures, and effort constraints, may impact differently in each sector of the fishery. There is a requirement that advice regarding the equity (throughout the fishery) of alternative management strategies be provided to complement the advice regarding the risk of adversely affecting the breeding stock under each strategy. A consequence of the high level of exploitation, and of the growing awareness by fishers of the potential impact of management initiatives on their harvest strategies, is a demand by industry for models that more accurately reflect the processes known to occur in the real fishery. The models used have therefore become increasingly complex, as they attempt to represent more realistically the biological processes, such as growth by moulting, and to reflect better the variation in biological parameters across the spatial extent of the fishery. Introduction of this spatial diversity has required that the models also include the migratory aspects of the rock lobsters’ life cycle. Only by introducing such detail is it possible to begin examining management strategies on a sector by sector basis. Because of the complexity of such spatial models, a thorough evaluation of their statistical behaviour is required, in order that uncertainty associated with model predictions is identified. As a consequence of their luxury status and the high prices received, most of the world’s spiny lobster stocks are heavily exploited and breeding stocks are significantly reduced from their original unfished levels. Managers of such fisheries therefore require a higher level of detailed advice, demanding the use of complex

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models such as that of Walters et al. (1993) (Fig. 21.3), if the impact of management changes is to be forecast with any accuracy. Such models place greater demands on research databases, relying on long time series of detailed catch and effort data, together with detailed research data on the biological processes that must be modelled.

References Annala, J.H. & Breen, P.A. (1989) Yield- and egg-per-recruit analyses for the New Zealand rock lobster, Jams edwardsii. N.Z. J. Mar. Freshwar. Res., 23, 93-105. Bergh, M.O. & Johnston, S.J. (1992) A size-structured model for renewable resource management with application to resources of rock lobster in the south-east Atlantic. S . Afr. J. Mar. Sci., 12, 1005- 16. Bowen, B.K. (1980) Spiny lobster fisheries management. In The Biology and Management of Lobsters, Vol. 11, Ecology and Management (Ed. by J.S. Cobb & B.F. Phillips), pp. 24364. Academic Press: New York, USA. Bowen, B.K. & Chittleborough, R.G. 1966. Preliminary assessments of stocks of the Western Australian crayfish, Panulirus cygnus George. Aust. J. Mar. Freshwat. Rex, 17, 93-121. Bowen, B.K. & Hancock, D.A. (1989) Effort limitation in the Australian rock lobster fisheries. In Marine Invertebrate Fisheries: Their Assessment and Management (Ed. by J.F. Caddy), pp. 37593. Wiley, New York, USA. Brown, R.S. (1991) A decade (198G1990) of research and management for the western rock lobster (Panulirus cygnus) fishery of Western Australia. Rev. Invest. Mar., 12, 204-22. Brown, R.S. & Caputi, N. (1986) Conservation and recruitment of the western rock lobster (Panulirus cygnus) by improving survival and growth of undersize rock lobsters captured and returned by fishermen to the sea. Can. J. Fish. Aquat. Sci., 43, 223-2. Caddy, J.F. (1977) Approaches to a simplified yield-per-recruit model for Crustacea, with particular reference to the American lobster, Homarus americanus. Manuscript Report 1445, Fisheries and Marine Service, Halifax, Nova Scotia, Canada. Caddy, J.F. (1979) Notes on a more generalized yield per recruit analysis for crustaceans using sizespecific inputs. Manuscript Report 1525, Fisheries and Marine Service, Halifax, Nova Scotia, Canada. Caddy, J.F. (1986) Stock assessment in data-limited situations - the experience in tropical fisheries and its possible relevance to evaluation of invertebrate resources. In North Pacific Workshop on Stock Assessment and Management of Invertebrates (Ed. by G.S. Jamieson & N. Bourne), pp. 379-92. Can. Spec. Publ. Fish. Aquat. Sci., 92. Caddy, J.F. (1987) Size-frequency analysis for crustacea: moult increment and frequency models for stock assessment. Kuwait Bull. Mar. Sci., 9, 43-61. Campbell, A. (1985) Application of a yield and egg-per-recruit model to the lobster fishery in the Bay of Fundy. North Am. J. Fish. Man., 5, 91-104. Caputi, N. & Brown, R.S. (1986) Prediction of recruitment in the western rock lobster (Panulirus cygnus) fishery based on indices ofjuvenile abundance. Can. J. Fish. Aquat. Sci., 43(1 I), 2131-9. Caputi, N., Brown, R. S . , & Chubb, C. F. (1995a) Regional prediction of the western rock lobster, Panulirus cygnus, commercial catch in Western Australia. Crustaceana, 68, 245-56. Caputi, N., Brown, R.S. & Phillips, B.F. (1995b) Predicting catches of the western rock lobster (Panulirus cygnus) based on indices of puerulus and juvenile abundance. ICES Mar. Sci. Symp., 199, 287-93.

398 Spiny Lobsters: Fisheries and Culture Chittleborough, R.G. & Phillips, B.F. (1975) Fluctuations in year-class strength and recruitment in the western rock lobster Panulirus Iongipes (Milne-Edwards). Aust. J. Mar. Freshwat. Res., 26, 317-28. Deriso, R.B. (1980) Harvesting strategies and parameter estimates for an age-structured model. Can. J. Fish. Aquat. Sci., 37, 268-82. Fogarty, M.J. & Idoine, J.S. (1988) Application of a yield and egg production model based on size to an offshore American lobster population. Trans. Am. Fish. SOC.,117, 350-62. Fogarty, M.J. & Murawski, S.A. (1986) Population dynamics and assessment of exploited invertebrate stocks. In North Pacijk Workshop on Stock Assessment and Management of Invertebrates (Ed. by G.S. Jamieson & N. Bourne), pp. 228-44. Can. Spec. Publ. Fish. Aquat. Sci., 92. Fox, W.W. (1975) Fitting the generalised stock production model by least squares and equilibrium approximation. Fish. Bull., 73(1), 23-36. Hall, N.G. & Brown, R.S.(1991) Modelling of the Western Australian rock lobster (Panulirus cygnus) fishery. Rev. Invest. Mar., 12, 255-60. Hall, N.G. & Brown, R.S. (1995) Delay-difference models for the western rock lobster (Panulirus cygnus) fishery of Western Australia. ICES Mar. Sci. Symp., 199, 399-410. Hall, N.G., Brown, R.S. & Caputi, N. (1990) A length-structured model of the western rock lobster fishery of Western Australia. In Dynamics of Complex Interconnected Biological Systems (Ed. by T.L. Vincent, A.I. Mees & L.S. Jennings), pp. 17-39. Birkhauser, Boston, MA, USA. Hancock, D.A. (1981) Research for management of the rock lobster fishery of Western Australia. Proc. Annu. Gulf Carib. Fish. Inst., 33, 207-29. Jones, R. (1974) Assessing the long term effects of changes in fishing effort and mesh size from length composition data. ICES Demersal Fish (Northern) Committee. CM 1974/F:33, 7 pp. Marchesseault, G.D., Saila, S.B. & Palm, W.J. (1976) Delayed recruitment models and their application to the American lobster (Homarus americanus) fishery. J. Fish. Res. Board Can., 33, 1779-87. Morgan, G.R. (1977) Aspects of the population dynamics of the western rock lobster and their role in management. Ph.D. thesis, University of Western Australia, Perth, Western Australia, Australia. Morgan, G.R. (1979) Assessment of the stocks of the western rock lobster Panulirus cygnus using surplus yield models. Aust. J. Mar. Freshwat. Res., 30, 355-63. Morgan, G.R. (1980) Population dynamics of spiny lobsters. In The Biology and Management of Lobsters, Vol. 11, Ecology and Management (Ed. by J.S. Cobb & B.F. Phillips), pp. 189-217. Academic Press, New York, USA. Morgan, G.R., Phillips, B.F. & Joll, L.M. (1982) Stock and recruitment relationships in Panulirus cygnus, the commercial rock (spiny) lobster of Western Australia. Fish. Bull., 80(3), 475-86. Pella, J.J. & Tomlinson, P.K. (1969) A generalised stock production model. Bull. Inter.-Am. Trop. Tuna Comm., 13, 421-96. Phillips, B.F. (1986) Prediction of commercial catches of the western rock lobster Panulirus cygnus. Can. J. Fish. Aquat. Sci., 43, 212630. Phillips, B.F. & Brown, R.S. (1989) The West Australian rock lobster fishery: research for management. In Marine Invertebrate Fisheries: Their Assessment and Management (Ed. by J.F. Caddy), pp. 159-81. Wiley, New York, USA. Pope, J.G. (1972) An investigation into the accuracy of virtual population analysis using cohort analysis. Res. Bull. Int. Comm. N W Atlant. Fish., 9, 65-74. Punt, A.E. & Kennedy, R.B. (1997) Population modelling of Tasmanian rock lobster, Jasus edwardsii, resources. Mar. Freshwat. Res., 48, 967-80. Punt, A.E., Kennedy, R.B. & Frusher, S.D. (1997) Estimating the size-transition matrix for Tasmanian rock lobster, Jasus edwardsii. Mar. Freshwat. Res., 48, 981-92.

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Ricker, W.E. (1958) Handbook of computations for biological statistics of fish populations. Bull. Fish. Res. Bd Can., 119, 300 pp. Schaefer, M.B. (1957) A study of the dynamics of the fishery for yellowfin tuna in the eastern tropical Pacific Ocean. Bull. Inter.-Am. Trop. Tuna Comm., 2(6), 245-85. Schnute, J. (1985) A general theory for analysis of catch and effort data. Can. J. Fish. Aquat. Sci., 42, 414-29. Walters, C. J., Hall, N., Brown, R. & Chubb, C. (1993) Spatial model for the population dynamics and exploitation of the Western Australian rock lobster, Panulirus cygnus. Can. J. Fish. Aquat. Sci., 50, 165e62.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 22

The Artificial Shelters (Pesqueros) used for the Spiny Lobster (Panrclirrcs argus) Fisheries in Cuba R. CRUZ Centro de Investigaciones Marinas, Calle 16 144 entre Ave. lera y 3era. Miramar Playa, Ciudad de la Habana, Cuba B.F. PHILLIPS Curtin Universiiy of Technology, P.0.Box U1987, Perth, Western Australia 6845. Australia

22.1

Introduction

The spiny lobster Panulirus argus is the most important fishery resource in the Caribbean and the species of highest commercial value in Cuba. It is the only lobster species in the world that is mainly caught by artificial shelters known as pesqueros in Cuba or casitas cubanas in Mexico (see Chapter 23). This artificial device is similar in construction in both Cuba and Mexico, and although the dimensions of the fibrocement plates or the number of tree trunks of which it is composed may vary, they generally they have a surface area of about 4 m2 (Fig. 22.1). Up to 200 lobsters are caught per shelter, which is a higher catch rate than with any other gear used in the fisheries. At present in Cuba, thepesqueros comprise 70% of the fishing gear and the catches made using them comprise 50% of the national total. Artificial shelters have greatly increased the catches from the tropical spiny lobster fisheries associated with shallow embayment and reef lagoons in Cuba and the Mexico Caribbean. They have now become more widespread in the Caribbean and there are plans to introduce them into other countries such as Australia (Phillips & Crossland, 1991), Sri Lanka and the Seychelles. In this chapter, aspects of the development, use, practical handling and impact of the pesqueros in the lobster fisheries in Cuba are presented and discussed.

22.2

History

The year when the first artificial structures were introduced in to Cuba is unknown, but there are indications that they have been used since World War I1 (Buesa, 1965; Cruz, 1982), especially in the Batabano Gulf. The original type of shelter was made by fishermen with the objective of increasing lobster concentrations and increasing catch, in areas lacking natural shelters. Fishers called these artificial sheltersjaulas or pesqueros de jata; they were made with trunks from the coastal palm tree called yuraguana, miraguano or guano (Coccothrinax miraquana). The dimensions and the

400

Artyicial Shelters used in Cuba

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(el

Fig. 22.1 Different types of pesquero in the Panulirus argus fishery in Cuba: (a) construction using the coastal palm tree Coccothrinax miraguana; (b) pesquero of fibrocement: construction using a fibrocement sheet and the trunk of a coastal palm tree or stick mangrove; (c) pesquero of fibercement; (d) pesquero of ferrocement; (e) pesquero of old car tyres.

number of tree trunks varied, although generally they covered a surface of about 4 m2 and sheltered up to 200 individuals per structure. The lobster net or chinchono was added as a method of harvesting the lobsters. This innovation produced a method of catching of lobsters that makes it one of the most productive gears in the lobster fisheries on a world scale (Cruz et al., 1990). In 1965, a campaign was initiated in Cuba to encourage the use of pesqueros and eliminate the other types of fishery equipment such as tridents or harpoons. In 1966, the lobster catch with pesqueros represented 20% of the total catch at the Batabano Gulf (Buesa, 1966). By the 1970s the lobster net withpesqueros and jauldns (trap-like set nets) had replaced the Antillean (fish) traps and bully nets (Baisre & Paez, 1981). In 1991, there were at least 250 000 pesqueros, and the pesquero and the jauldns took 50% and 30% of the total national catch, respectively. The use of this gear is variable in the different enterprises around Cuba, partly because of the characteristics of the zones and seasons, and partly because of local customs and ideas about how best to achieve the highest catch.

402 Spiny Lobsters: Fisheries and Culture 22.3 22.3.1

Pesqueros Construction

From the 1940s to the 1970s, the coastal palm (C. rniruguunu) was the main material used in the construction of the pesquero by the Cuban fishermen. It is a fibrous material, very resistant to the destructive action of the marine environment, and can last for an average of 3 years in the sea without repair. These palms grow in muddy, intertidal areas, and the felling, transportation and storage of the trunks was carried out in the months in which the lobster season was closed. The shelter’ s frame, made of the palm trunks, was joined by nails from 125 to 150 mm in length and the ends were reinforced by galvanized wire. The dimensions and the number of trunks were variable, but each pesquero had around 28 trunks, and such trunks were 1.8 m long, 1.60 m wide and 0.35 m high, with a surface area of about 4 m2. The roof of the pesquero was single or double but always constructed in such a manner that in any position on the bottom it would permit lobsters to use it as a refuge. In the 1960s, the cost of construction of a pesquero, including construction labour and placing it in the sea, was about US $2.00 (Buesa, 1965). At the beginning of the 1970s, zinc plates were added to the pesquero de juta, and later fibrocement plates were used, because of the scarcity of palms and the amount of time and physical effort that fishermen had to spend in the location and felling of trees in very widespread regions. In some regions they even began to use mangrove trunks and old car tyres. From 1980, because of a national protection policy for coastal vegetation and to industrialize the construction of the shelters, they began to be constructed mainly of fibrocement plates and to a lesser extent ferrocement plates (Cruz et al., 1990). Surveys carried out during 1984 and 1985 showed that a change in the composition of materials and technology used in the construction of the pesqueros had taken place. Sixty per cent of the pesqueros were then constructed of a mixture of fibrocement plates and coastal palm trunks, 14% of miraguana or jata, 13% of fibre or fibrocement, 12% of car tyres and mangrove sticks and 1% of other materials (Fig. 22.1). Ferrocement pesqueros are constructed by joining two plates of fibrocement manufactured specifically for this purpose. Two wooden trunks are located at the sides and the ends, which are fixed with nails and reinforced by galvanized wire. The cost of production is about US $25.00 and they measure 1.60 m long, 10 m wide and 0.35-0.40 cm high. These dimensions are smaller than those of the traditional pesquero, thus facilitating transportation and handling, and its construction is simple. Pesqueros constructed of tyres have a rectangular entrance 120 mm wide per 150 mm of height, plus two or three holes for drainage. The two lids that cover the

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tyre are usually of mangrove stems set in the form of a lattice and fixed to the tyre with monofilament nylon rope.

22.3.2

Fishing techniques

The main lobster grounds are located in shallow, very clear and calm areas, where the seabed is covered in seagrass (Thalassia testudinum). Fishermen place their pesqueros in groups of 15 to 20, on a line in a zigzag manner with about 25-30 m between each pesquero. The fishing operation begins when the skipper of the vessel, assisted by a fisherman who is standing at the mast and the rest of the crew at the bow, locates the pesqueros, orientating himself using natural features on the coast and keys or by a predetermined route with a compass. Fishing is carried out from a dinghy by two fishers who alternate the fishing operations. While one fisher rows to the pesquero, the other uses a wooden bucket with a flat glass on the bottom (waterglass); this allows him to observe the bottom and to detect lobsters in the pesquero. Later on, a ‘prickle’ is used (made with a stick of different sizes with an L-shaped wire at one end) to scare the lobsters out of the shelter and catch them with a lobster net, which is placed around the pesquero. In order to drop the lobster net, the boat is positioned favouring the current. Several metres from the pesquero the cod end is dropped; the fishermen rows the other way around in such a way that the pesquero is at the centre of the circle that forms the sides of the lobster net; to one end of the sides, a rope is fastened that is attached to the bow of the boat. The lobsters under thepesqueros are scared out with the prickle towards the cod end; the rope is joined to the end of the cod end, then the net is lifted and the cod end is lifted into the boat. This fishing operation lasts for around 1&15 min, during which time all of the lobsters in the pesquero are caught. An alternative method is to lift the shelter on one of its sides, from the boat, with a hook fixed at the end of a wooden stick and to support it on a second hook located 1.5 m from it, in order to set the pesquero in an inclined position and facilitate the rapid exit of the lobsters. The different types of auxiliary equipment used in the lobster fishery are illustrated in Fig. 22.2. The fishers of the south-eastern region carry out the previously described fishing operation through free diving at depths from 6 to 12 m. Two divers position the lobster net around the pesquero, then they lift it and later on scare out the lobsters into the cod end, lift the net into the boat and recover the lobsters. Two fishermen carry out this operation in approximately 10-12 min. The crews in this region are formed of four divers, a boatman and a skipper of the boat; these boats average 16 t of lobsters/diver per boat annually. The technique used by the fishermen of the north-eastern region is quite different. Their technique is to drop an unbaited trap, generally with one or two buoys, near the pesqueros. Fishing is carried out from an auxiliary boat with two fishermen on

404 Spiny Lobsters: Fisheries and Culture

Fig. 22.2 Different equipment used by the fishers to check and lift the pesqueros in Cuba: (a) glass-bottomed tub for observing; (b) the prickle, constucted with a stick and wire; (c) bully net; (d) lobster net.

board; while one manoeuvres the boat the other one lifts the traps. The lobsters are taken out of the trap by hand.

22.3.3

Seasonality

Fishing is seasonal and there is a high catch in June at the beginning of the fishing season. Around 1400-2700 t are taken annually in June in the four regions of the Cuban shelf, in which the catches of the pesqueros represent 95%. Because of the closed season from March to May, a colonization process takes place as the recruits (juveniles of about 2 years of age) enter the pesqueros in the fishing areas (Cruz et al., 1991a) which, together with lobsters of 3 and 4 years of age, form the main part of the catch from the pesqueros. In some years, appreciable variations in the availability of lobster that colonized the pesqueros have been observed owing to environmental factors. Heavy rain in June, associated with other hydrometeorological phenomena, may produce considerable decrease in catches (Cruz et al., 1986a), not only because of the limitations placed on the fishing effort, but also because they cause displacements of lobsters to other areas (Cruz et al., 1981).

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During the late summer months (July-August) a decrease in catches occurs in the pesquero, reaching minimum values in September. Buesa (1965, 1972) showed that this decrease in catches is associated with a migration of larger individuals, from shallow to deeper and cooler waters. In September a general change is observed in the weather conditions, characterized by a sudden decrease in air temperature, minimum values of atmospheric pressure and wind intensity, a significant decrease in insolation, an increase in the daily photoperiod and a change in wind direction (Garcia et al., 1991). These conditions trigger the pre-migratory behaviour of lobsters. During the last quarter of the year, catches in the pesqueros again increase, because of migrations during autumn-winter, when 3WO% of the total annual catch in Cuba is caught using jauldns (Fig. 22.3). The intensity of winter fronts, depressions, hurricanes and continental cold air masses have a great influence on the catches obtained. Herrnkind & Cummings (1964), Herrnkind & McLean (1971), Herrnkind et al. (1973), Kanciruk & Herrnkind (1976) showed that seasonal migrations of P . argus are characteristic of adult populations and the concentration and subsequent movements occur after a storm-induced decline in water

Fig. 22.3 Seasonality of the catch of lobster Panulirus argus on the shelf of Cuba.

406 Spiny Lobsters: Fisheries and Culture temperature. Garcia et al. (1991), however, suggest that this mass migration may be provoked by other meteorological processes such as the intensity of winter fronts, depressions, hurricanes or continental cold air masses; these can have a great influence on the catch volumes, without a decline in the temperature of the water.

22.3.4

Size and sex composition

The gregarious behaviour of juvenile and adult lobsters in natural shelters (Lindberg, 1955; Khaader, 1964; Fielder, 1965; Berry 1971a, b; Lipcius & Cobb, 1994) is shown in the individuals that colonize the pesqueros. Figure 22.4 shows the size and sex composition of the lobsters in the pesqueros of the Gulf of Batabanb. Lobsters from 20 to 170 mm carapace length (CL) are found under the pesqueros, although occasionally post-puerulus from 12 to 15 mm have been caught (Cruz, unpubl. data). A high colonization rate occurs during the period of maximum recruitment (MarchMay) in the fishing areas (Cruz, 1999). During these months of the closed season, 40-50% of the population in the fishing area are individuals lower than the legal minimum size (69 mm). No significant differences (p < 0.01) were found between the mean sizes of individuals that cohabit in the pesquero during March-June. From July, the mean size increases, as the number of recruits decreases, until December. In January, a new cohort begins its recruitment (Fig. 22.4). In each year, the mean CL by sex is lowest in March-May, as the number of recruits increases, and this feature of the population is very consistent in any year (Fig. 22.5). The number of lobsters found in the pesqueros is very variable and this probably reflects the population density in each area, the age structure and the type of artificial shelter used. Cruz et al., (1986b) reported that the mean size in a nursery area is significantly different (p < 0.01) between lobsters that colonize the pesqueros and lobsters inhabiting concrete blocks. The mean size of the lobsters increases with the depth of capture (r = 0.9262, p = 0.05; Fig. 22.6), with the mean CL length of the male being significantly higher (p < 0.05) than that of the female, from 6 m to the maximum depth. The mean size of females in reproductive condition remains relatively constant, averaging 87.1 mm CL, in depths from 3 to 9 m, but is higher (p < 0.05) at 13 m (Fig. 22.6). In natural shelters, Kanciruk & Herrnkind (1976) found the same relationship between lobster size and depth. The sex ratio of the lobster in the pesqueros does not differ significantly from 1:1, which is the same as P. argus in natural shelters (Creaser, 1952; Munro, 1974; Kanciruk, 1980; Lyons et al., 1981; Cobb & Caddy, 1989). However, males exceed females significantly in the 30-40 mm CL range and above 100 mm CL. At the larger sizes, males have a higher growth rate than females and/or a reduced mortality rate (Fig. 22.6). Similar differences occur in the Bahamas (Simpson, 1976). Lobster sampling using different artificial shelters (pesqueros, concrete block and seaweed collectors) to catch the lobster stages in the Gulf of Batabanb, permit the

401

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Fig. 22.4 Monthly sizefrequency distributions and mean carapace length (mm) by sex of Panulirus argus in the Gulf of Batabanb, Cuba.

408 Spiny Lobsters: Fisheries and Culture

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characterization of the main events in the complex life cycle of P . argus in Cuban waters (Cruz, 1999). The puerulus arrive at the coast every month with mean CL of 5.63 mm (between 4.24 and 6.09 mm) and settle in a complex substrate, especially hard-bottom habitat covered by red macroalgae Laurencia spp. (Marx & Herrnkind, 1985; Herrnkind & Butler, 1986; Lalana et al., 1989) and 29 other species of algae (Brito & Suarez, 1994). Pueruli becoming post-pueruli (algal phase) after settlement with a mean of 7.27 mm CL (between 6.0 and 16.5 mm, CL). Buttler & Herrnkind (1997) report that the algal phase remains within benthic algae in the range between

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Fig. 22.7 Sex ratios of the spiny lobster Panulirus argus in the pesqueros in the Gulf of Batabanb, Cuba, 1990.

410 Spiny Lobsters: Fisheries and Culture 5 and 15 mm CL, because they consider a puerulus stage as a post-larva and not a transitional pelagic stage. Post-pueruli become juveniles between 16 and 20 mm (1520 mm in Florida; Forcucci et al., 1994), the sexes can be distinguished and they emerge from the algae with gregarious behaviour. The mark-recapture results indicate that more than 40% of the juveniles between 45 and 50 mm CL become nomadic @re-recruits) and recruit to the fishery with a mean of 76.77 mm CL (74.07-79.32 mm); this is significantly larger (81 = 3; t = 24.57; p < 0.001) than the mean resident juveniles in the nursery area (51.04 mm CL). These data concur with the results of Forcucci et al. (1994) and Butler & Herrnkind (1997), who estimated that at about 45 mm CL the juveniles become nomadic and migrate at 76 mm CL to the fishing grounds (Davis, 1978). The adult phase starts at first maturity which ranges from 78 to 81 mm CL (Cruz & L e h , 1991; Baisre & Cruz, 1994). Figure 22.8 summarizes the recruitment process by CL.

Reproduction

22.3.5

In locations with high reproductive activity, such as near to the edge of the shelf, ovigerous females constitute 80% of the total females collected in the pesqueros. Females bearing eggs range in size from 70 to 139 mm CL. Cruz & de Leon (1991) were able to characterize different aspects of the reproductive dynamics of lobsters in their natural environment, through the study ofpesqueros at 42 locations in the Cuban shelf. Figure 22.9 shows the annual reproductive cycle of P.argus in the Cuban archipelago. 45

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Fig. 22.8 Summary of the life history of the spiny lobster (Panulirus argus) in Cuba.

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The authors observed, while diving on the pesgueros, that the gregarious behaviour of pre-adults is not affected by the presence of male or females in different reproductive stages. Different moulting stages have been observed, as well as females with mature ovaries, with spermatophoric mass in different stages of deterioration and ovigerous females in different development phases.

412 Spiny Lobsters: Fisheries and Culture 22.3.6

Predators

In the benthic phase, juveniles and adults, are predated by many species of fish. In Cuba 50% of the stomach contents of the nurse shark (Gingfymostoma cirratum) were found to be lobsters. Of a total of 21 sharks found in pesqueros, with a total length of approximately 68-132 cm, 60% had full stomachs and of those 50% of the remains were lobsters (Cruz et al., 1986b). The pesqueros are also occasionally inhabited by red grouper (Epinephelus morio) and other fish such as Cuvier’s burrfish, Cuban snapper (Lutjanus cyanopterus), grey snapper (Lutjanus griseus) and filefish (Balistidae), which are potential predators of lobster. The red-tail snapper (Lutjanus synagris) and the spotted moray (Gimothorax moringa) were observed to prey on juveniles (Buesa, 1965; Aitken, 1977). A great number of these species is reported as predators in the Cuban shelf, including the red snapper (Lutjanus synageris), red-tail snapper, yellowtail snapper (Ocyurus chrysurus) (Buesa, 1965), ray (Dasyatis sp.), different types of shark (Buesa, 1965), triggerfish (Bafistesvetula) and old wife (Kanciruk, 1980). The octopuses that are the lobster’s main predator in pots in Australia (Joll, 1977) are not abundant along the Cuban coasts, nor are the sea turtles and dolphins that are also important predators in other areas (Munro, 1974). The risk of predation is much higher in the juvenile than the adult. By providing more artificial shelter in the nursery areas, juvenile mortality is probably reduced and the local recruitment of P. argus may be increased by augmenting natural shelter with well-designed artificial structures.

22.3.1

Associated fauna

A great variety of organisms grows on the pesqueros, particularly those constructed with coastal palms, including gastropods (Cypraea zebra, Cepridufa oculeata), pelecypodos (Spondylus americanus, Pinctada radiata and Arca zebra) and polychaetes, which can form a food source for the lobsters. Around and inside the pesqueros there are often remains of molluscs (Cruz et al., 1986b). Lalana et al. (1987) and Herrera et al. (1991) examined the stomach contents of lobsters of sizes 70-168 mm CL, at different depths, and found that the most abundant food organisms were gastropods, Brachyura, Pelecypoda and sea urchins. Other invertebrates associated with the pesqueros are species of Brachyura (Portunus sebae, Mithrax spinossisima, Sternohyncus seticornis and portunus spinimanus), Echinoidea (Diadema antillarun and Lytechinus variegatus), corals (Porites porites and Siderastrea radians) and several species of sponges (Cruz et af., 1986b). The food potential of the pesquero may increase the occupation and growth rates of the lobster, owing to the similarity of the communities that inhabit the shelter to the food normally eaten by the lobsters.

Artificial Shelters used in Cuba 22.3.8

4 13

Ecology of the pesqueros

The mode of action of these shelters is not fully understood, although there is a common belief among fishermen that they not only concentrate the lobsters but also provide shelter from predators and therefore increased yields. Evidence from field observations and experiments suggests that shelter limits spiny lobster abundance in certain habitats such as reefs and seagrass beds, and that there is a dynamic interplay between shelter and food availability (Eggleston, 1991) (see also Chapter 23). Although the availability of shelter seems to be crucial, especially for immature lobsters, it seems improbable that available shelter is the sole factor determining population size because, as can be expected, natural mortality drops rapidly with size and age.

22.3.9

Catch and effort

The four shelves of the Cuban Archipelago are relatively geographically isolated because of the very narrow shelf separating them (Fig. 22.10), and appreciable differences are observed in yield per surface unit among zones and coasts. Tendencies in catch and effort are therefore treated as if these were independent population units, although it is unknown whether their fishing populations constitute a single or different stocks. Because of the range of fishing gear used in the fishery it is not possible to have a single measure of effort. However, about 48% of the catch from 1985 to 1990 was taken using the pesqueros. Overall, the pesqueros produced an average of 5706 t of lobster annually from 1985 to 1990, using around 23 OOOpesqueros,which was about 65% of the catch of the Batabanb Gulf, 20% of the south-eastern region, 11% of the north-eastern region and 4% of the north-western region. Fishing effort is now measured as the number of pesqueros checked by the fishers. It might have been possible to use the estimates of the number of pesqueros, but not all of these are checked on a regular basis.

Fig. 22.10 Map of Cuba showing the fishing zone for Panulirus argus and the yield per area of surface (mean of 340 kg/km2 in the shelf).

414 Spiny Lobsters: Fisheries and Culture Figure 22.1 1 shows the catch and fishing effort history of the Cuban lobster fishery. From 1970 to 1979, the annual catches of the pesqueros fluctuated around 3488 t. Between 1978 and 1985, the catch rose to 6450 t. This appears to have been correlated with the use of increasing numbers of pesqueros. The effect of strong fishing pressure, combined with natural fluctuations in the levels of recruitment, environmental conditions and variations in catchability of the lobsters (see also Chapter 23) were all involved in variations in the annual catch (Cruz et uf., 1989, 1991b). Fishing effort increased from 4 x lo5 pesqueros checked in 1975 to 12.5 x lo5 in 1987. The fishery showed a marked reduction in catch in 1990, owing to a reduction in the recruitment (Chapter 7) during a period of large increases in fishing effort, and the consequent decline in catch per unit effort (CPUE). It was decided, in 1990, to lengthen the closed season to 4 months and not to increase the number of pesqueros or juufdns, in order to contain the fishing effort. In the Gulf of Batabanb (Fig. 22.12a) 52% of the catch is currently with the pesqueros and 42% with juufins. Catches with the pesquero were relatively stable between 1979 and 1991, reaching a maximum in 1980 and 1982 of 5000 t and 4600 t, respectively, but decreasing to an average of 3625 t between 1983 and 1991, with the lowest catches of 2565 t in 1990. It is clear that there was a marked decline in the CPUE from 1979 to 1990, although it increased again in 1991, probably because the effort was constrained.

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416 Spiny Lobsters: Fisheries and Culture In the south-eastern region since 1985, the lobster catch increased more rapidly with the pesqueros than with the jauldns. During 1990, 54% of the catch was obtained using pesqueros and 27% using jauldns. Catches have fluctuated appreciably since 1982 and ranged between 1100 t and 1390 t (Fig. 22.12b), in contrast to the increased rates of fishing effort up to 1989. As a result, a significant decrease of more than 50% occurred in the CPUE. Because the fishing effort was stabilized between 1989 and 1991, the CPUE started to increase in 1990/91. On the south coast of Cuba, where 78% of the nation’s pesqueros were fished, the increase in effort was related to the number of pesqueros. It has been suggested that in this region the pesqueros significantly influence the fish mortality rate (Puga, et al., 1991). The unbaited trap is the main fishing gear in the north-eastern region, contributing 7 5 4 0 % of the catches of that area. Lobster fishing using pesqueros is carried out by dropping traps around the pesqueros. This technique only contributes about 15% of the catch of the region. Catches showed a tendency to increase until 1987, then fell during the last few years (Fig. 22.12~).No definitive tendency is observed in this region between fishing effort and CPUE, partly owing to the technique of combining traps and pesqueros. The pesqueros in the north-western region contributed 63% to the mean annual catch of the region during the past few years, followed by the jauldns with 35%. Catches with the pesqueros stabilized around 250 t between 1984 and 1986 (Fig. 22.12d) and then decreased as the gear increased.

22.4

Conclusions

The effects of the containment of effort including the number of pesqueros which occurred in the past few years have yet to be fully evaluated, but should lead to a stabilization of the Cuban fishery. However, continual changes in the design of the pesqueros are occurring even today, which will mean that the effort in the fishery is continuing to change. An integrated series of field studies is needed to determine how artificial shelters function to enhance commercial catches by aggregation of lobsters and/or by enhancement of lobster production for the long-term successful management of the fishery.

References Aitken, K.A. (1977) Jamaica spiny lobster investigations. F A 0 Fish. Rep., 200, 11-22. Baisre, J.A. & Cruz, R. (1994) The Cuban spiny lobster fishery. In Spiny Lobster Management (Ed. by B.F. Phillips, J.S. Cobb & J. Kittaka), pp. 119-32. Blackwell Scientific Press, Oxford, UK. Baisre, J.A. & Paez, J. (1981) Los recursos pesqueros del archipielago Cubano. Esrudios WECAF, 8, 79 PP.

ArtiJi:cial Shelters used in Cuba

417

Berry, P.F. (1971a) The biology of the spiny lobster Panulirus homarus (Linnaeus). Invest. Rep. Oceanogr. Res. Inst., 28, 1-76, Berry, P.F. (1971b) The spiny lobsters (Palinuridae) of the east coast of southern Africa: distribution and ecological notes. Invest. Rep. Oceanogr. Res. Inst., 27, 1-23. Brito, M., & Suarez, A.M. (1994) Algas asociadas a Laurencia implicata (Ceramiales, Rhodophyta) en la Cayeria de Bocas de Alonso, Cuba. Rev. Invest. Mar.,15(2), 93-8. Buesa, R.J. (1965) Biologia de la langosta Panulirus argus, Latreille, 1804 (Crustacea, Decapoda, Reptantia) en Cuba. INPP/CIP, Cuba (mimeogr.), 228 pp. Buesa, R.J. (1966) Bioecologia y pesca de la langosta Panulirus argus, Latreille, 1804 (Crustacea, Decapoda, Reptantia) en Cuba, Res. Invest. (ms), 164 pp. Buesa, R.J. (1972) La langosta espinosa Panulirus argus: su pesca y biologia en aguas cubanas. INP/ CIP, Cuba. Reun. Balance. Trab., 3(1), 29-78. Butler, M.J. & Herrnkind, W.F. (1997) A test of recruitment limitation and the potential for artificial enhancement of spiny lobster (Panulirus argus) population in Florida. Can. J. Fish. Aquat. Sci., 54, 452-63. Cobb, J.S. & Caddy, J.F. (1989) The population biology of decapods. In Marine Invertebrate Fisheries: Their Assessment and Management (Ed. by J.F. Caddy), Part 1, pp. 327-74. Wiley, New York, USA. Creaser, E.P. (1952) Sexual dimorphism in weight and length relationships of the Bermuda spiny lobster. Proc. Cur Carib. Fish. Inst., 4(1951), 59-63. Cruz, R. (1982) Los recursos langosteros en el archipielago cubano. En memorias del grupo de trabajo sobre la langosta. WECAF Rep., 36, 125-50. Cruz, R. (1999) Variabilidad del reclutamiento y pronbstico de la pesqueria de langosta (Panulirus argus, Latreille, 1804) en Cuba. Tesis presentada en opci6n del grado cientifico de Doctor en Ciencias Biologicas. Ciudad de la Habana, Cuba, 99 pp. Cruz, R. & Leon, M.E. de (1991) Dinimica reproductiva de la langosta (Panulirus argus) en el archipielago cubano. Taller Internacional sobre Ecologia y Pesqueria de Langosta. La Habana, Cuba, 12-16 Junio, 1990 Rev. Inv. Mar., 12(1-3), 23445. Cruz, R., Baisre, J.A., Diaz, E., Brito, R., Garcia, C. & Carrodeguas, C. (1990) Atlas biologico pesquero de la langosta en el archipielago cubano. Pub. ESP.Rev. Cub. Invest. Pesq. Rev. Mar Pesca, 125 pp. Cruz, R., Brito, R., Diaz, R. & Lalana, R. (1986a) Ecologia de la langosta (Panulirus argus) al se de la Isla de la Juventud. I. Colonizacion de arrecifes artificiales. Rev. Invest. Mar. (Cuba), 7(3), 3-17. Cruz, R., Brito, R., Diaz, R. & Lalana, R. (1986b) Ecologia de la langosta (Panulirus argus) a1 se de la Isla de la Juventud. 11. Patrones de mouimiento. Rev. Invest. Mar. (Cuba), 7(3), 19-35. Cruz, R., Coyula, R. & Roch, J. (1981) Analisis de la pesqueria de langosta: Resultados del levante de Veda y estudio de la distribucion de juveniles. CIPIMIP, 1, 1-33. Cruz, R., Leon, M.E. de, Diaz, E. Brito, R. & Puga, R. (1991a) Reclutamiento de langosta (Panulirus argus) a la plataforma Cubana. Taller Internacional sobre Ecologia y Pesqueria de Langosta, Ciudad de la Habana, Cuba 12-16 Junio de 1990, Rev. Invest. Mar., 12(1-3), 66-75. Cruz, R., Leon, M.E. de, Puga, R., Sotomayor, R., del Castillo, J., Salahange, P., Camejo, J., Molina, E., Rodriguez, A., Lopez-Trigo, T., Hernandez, H. & Santos, A. (1989) Estado actual y perspectivas de la pesqueria de langosta en aguas cubanas. Rep. Tec., 5, 1-40. Cruz, R., Sotomayor, R., Leon, M.E. de & Puga, R. (1992b) Impact0 en el manejo de la pesqueria de langosta (Panulirus argus) en el archipitlago cubano. Taller Internacional sobre Ecologia y Pesqueria de Langosta. La Habana, Cuba, 12-16 Junio 1990, Rev. Invest. Mar., 12(1-3), 246-53. Davis, G.E. (1978). Field evaluation of a tag for juvenile spiny lobster, Panulirus argus. Trans. Am. Fish. Soc., 107(1), 100-3.

418 Spiny Lobsters: Fisheries and Culture Eggleston, D.B. (1991) Stock enhancement of Caribbean spiny lobster, Panulirus argus Latrielle, using artificial shelters: patterns of survival and dynamics of shelter selection. D.Phil. thesis, School of Marine Science, 143 pp. Fielder, D.R. (1965) A dominance order for shelter in the spiny lobster Jams Ialandii (H. Milne Edwards). Behaviour, 24, 236-45. Forcucci, D., Butler, M.J. & Hunt, J.H. (1994) Population dynamics of juvenile Caribbean spiny lobster, Panulirus argus, in Florida Bay, Florida. Bull. Mar. Sci., 54(3), 805-18. Garcia, C., Hernandez, B, Baisre, J.A. & Cruz, R. (1992) Factores climaticos en las pesquerias cubanas de langosta (Panulirus argus): su relacion con las migraciones masivas. Taller Internacional sobre Ecologia y Pesqueria de Langosta, Ciudad de la Habana, Cuba, 12-16 junio, 1990. Rev. Invest. Mar., 12(1-3), 131-9. Herrera, A., Brito, R., Ibarzabal, D., Gonzalez-Sanson, G., Gotera, G., Diaz, E. & Foyo, J. (1990) Alimentacion natural de la langosta Panulirus argus en el area de 10s lndios y su relacion con el bentos. Taller Internacional sobre Ecologia y Pesqueria de Langosta, Ciudad de la Habana, Cuba 12-16 junio, 1990. Rev. Invest. Mar., 12(1-3), 172-82. Herrnkind, W.F. & Butler, M.J. (1986) Factors regulating postlarval settlement and juvenile microhabitat use by spiny lobsters. Panulirus argus Mar. Ecol. Prog. Ser., 34, 23-30. Hermkind, W.F. & Cummings, W.C. (1964) Single file migrations of spiny lobster Panulirus argus (Latreille). Bull. Mar. Sci. Gurf Carib., 14, 123-5. Herrnkind, W.F. & McLean, R. (1971) Field studies of orientation, homing, and mass emigration in the spiny lobster, Panulirus argus. Ann. N . Y. Acad. Sci., 188, 359-77. Herrnkind, W.F., Kanciruk, P., Halusky, J. & McLean, R. (1973) Descriptive characterization of mass autumnal migrations of spiny lobster, Panulirus argus. Proc. Gulf. Carib. Fish. Inst., 25, 79-98. Joll, L.M. (1977) The predation of pot caught western rock lobster (Panulirus fongipes cygnus) by octopus. W . Aust. Dept Fish. Will. Rep., 29, 1-58. Kanciruk, P. (1980) Ecology of juvenile and adult Palinuridae (spiny lobsters). In The Biology and Management of Lobster (Ed. by J.S. Cobb & B.F. Phillips), Vol. 2, Part 1, pp. 59-92. Academic Press, New York, USA. Kanciruk, P. & Herrnkind, W.F. (1976) Autumnal reproduction in the spiny lobster, P. argus, at Bimini, Bahamas. Bull. Mar. Sci., 26(4), 417-32. Khandker, N.A. (1964) Sponge as shelter for young spiny lobsters. Trans. Am. Fish. SOC.,93, 204. Lalana, R., Capetillo, N., Brito, R., Diaz, E. & Cruz, R. (1989) Estudio del zoobentos asociado a Laurencia intricata en un area de juveniles de langosta a1 se de la Isla de la Juventud. Rev. Invest. Mar., 10, 207-18. Lalana, R., Diaz, E., Brito, R., Kodjo, R. & Cruz, R. (1987) Ecologia de la langosta (Panulirus argus) al se de la Isla de la Juventud. 111. Estudio cualitativo y cuantitativo del bentos. Rev. Invest. Mar. (Cuba), 8, 31-53. Lindberg, R.G. (1955) Growth, population dynamics and field behaviour in the spiny lobster Panulirus interruptus (Randall). Univ. Calif. Publs. Zool., 59, 127-48. Lipcius, R.N. & Cobb, J.S. (1994) Introduction: ecology and fishery biology of spiny lobster. In Spiny Lobster Management (Ed. by B.F. Phillips, J.S. Cobb & J. Kittaka), pp. 1-30. Fishing News Books, Blackwell Scientific Publications, Oxford, UK. Lyons, W.G., Barber, D.G., Foster, S.M., Kennedy, F.S., Jr. & Milano, G.R. (1981) The spiny lobster, Panulirus argus, in the middle and upper Florida keys: population structure, seasonal dynamics and reproduction. Flu. Mar. Res. Publ., 38, 1-38. Marx, J.M., & Herrnkind, W.F. (1985) Macroalgae (Rhodophyt: Laurencia spp.) as habitat for young juvenile spiny lobsters, Panulirus argus. Bull. Mar. Sci., 36, 423-31. Munro, J.L. (1974) The biology, ecology, exploitation and management of Caribbean reef fishes: crustaceans (spiny lobsters and crabs). Res. Rep. Zool. Dept Univ. West. Indies, 3, Part VI, p. 51.

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Phillips, B.F. & Crossland, C.J. (1991) Rock lobster fisheries: enhanced commercial yields by artificial shelters? In Sustainable Development for Traditional Inhabitants of the Torres Strait Region: Proceedings of the Torres Strait Baseline Study Conference (Ed. by D. Lawrence & T. Cansfield-Smith), pp. 295-30 1. Australian Government Publishing Service for the Great Barrier Reef Marine Park Authority, Canberra, Australia. Puga, R., Leon, M.E. de & Cruz, R. (1990) Evaluacion de la pesqueria de langosta espinosa Panulirus argus en Cuba. Taller Internacional sobre Ecologia y Pesqueria de Langosta. La Habana, 12-16 Junio, 1990. Rev. Invest. Mar., 12(1-3), 286-92. Simpson, A.C. (1976) Size composition and related data on the spiny lobster (Panulirus argus) in the Bahamas in 1966. Crustaceana, 31(3), 225-32.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 23

The Use of Artificial Shelters (Casitas) in Research and Harvesting of Caribbean Spiny Lobsters in Mexico P.BRIONES-FOURZAN and E. LOZANO-ALVAREZ

Universidad Nacional

Autdnoma de Mexico, Instituto de Ciencias del Mar y Limnologia, Unidad Acadimica Puerto Morelos, Ap. Postal 1152. Canctin Q R 77500, Mexico

D.B. EGGLESTON

Department of Marine, Earth and Atmospheric Sciences. North

Carolina State University, Raleigh, NC 27695-8208, USA

23.1

Introduction

Artificial reefs are in use world-wide as a means of increasing local abundance of finfish and invertebrates (for reviews see Bohnsack & Sutherland, 1985; D’Itri, 1985; Conan, 1986; Bohnsack, 1989; Seaman & Sprague, 1991). However, only recently has there been a comprehensive approach, employing replicated and controlled field experiments and observations, to identify the ecological role of these shelters. Despite the absence of information on the function of artificial shelters, two spiny lobster fisheries have been based for several decades on the extensive use of artificial shelters: the Cuban fishery for Panulirus argus (Chapter 22), and the fishery for this same species in some areas of the Mexican Caribbean coast. The spiny lobster fishery in the Mexican Caribbean (coast of the state of Quintana Roo) is based on a wide variety of fishing gear and methods, including traps, nets, SCUBA, hookah, skin diving, and artificial shelters called casitas cubanas, sornbras or simply casitas. This array of fishing gear makes the fishery very complex and has precluded the application of standard surplus yield models, owing to the difficulty in standardizing units of effort (Lozano-Alvarez, 1992, 1994). Casitas are used extensively in the central part of the Quintana Roo coast, in two bays called Bahia de la Ascension and Bahia Espiritu Santo. In these areas, a highly efficient organizational structure, reminiscent of a closed-access fishery, has been developed by the fishermen. Both bays have long been recognized as nursery areas for juvenile P. argus, which comprises over 95% of the spiny lobster catch in the state. The production of this casita-based fishery between 1983 and 1999 has accounted for, on average, 26% of the total lobster catch of the state. However, in the late 1990s, the use of casitas has expanded to other areas of Quintana Roo, such as the mainland coast in front of Isla Mujeres, and also to the neighbouring state of Yucatan. 420

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This chapter reviews the current state of the research on the mode of operation of artificial shelters for spiny lobsters, with an emphasis on the Mexican casita-based fishery in Bahia de la Ascensih, where most of the research on this fishery has been conducted.

23.1.1

Evolution of casitas and the fishing technique

The first type of casita used in Bahia de la Ascension was similar to the first Cuban design, and consisted of a wooden frame about 2 m long x 1.5 m wide made of six poles cut from the trunks of a local palm (Thrinax radiata) and a wooden roof made of a number of poles nailed to the frame. The wood of this palm is very dense and sinks rapidly to the bottom, where it can last for up to 6 years. Some fishermen would nail an additional two poles to the top of the roof, in the event of the casita being overturned by dolphins which, fishermen claim, perform this task to prey on the lobsters. During the 1980s, large-scale exploitation seriously reduced the abundance of T. radiata (Olmsted & Ercilla, 1988), which was also used for construction purposes, and led to the utilization of different roofing materials for casitas, such as metal from discarded 200-litre drums, sheets of corrugated asbestos or plates of ferrocement (Miller, 1982). Through an agreement between the co-operatives fishing in the bays and local authorities, a ban on cutting T. radiata within the Sian ka’an Biosphere Reserve (which includes both bays) was established in 1988 and fishermen had to import the trunks of the palm from more distant locations. Until 1995, the most prevalent casitas were those built with ferrocement as the roofing material and palm trunks as the frame material (Fig. 23.la). These casitas measured 1.8 m long x 1.2 m wide x 6 8 cm high. However, in 1996, T. radiata was considered an endangered species and it was forbidden to cut or introduce any trunks of this palm into the Sian ka’an Biosphere Reserve. Hence, casitas are

Fig. 23.1 Schematic representation of the types of casitas currently in use in Bahia de la Ascension: (a) trunk-ferrocement casita, with a frame constructed with trunks of Thrinax radiata and a plate of ferrocement as the roof; (b) ferrocement ‘box’ casita, used on hard grounds; (c) ferrocement ‘caguamo’ casita, used on softer grounds.

422 Spiny Lobsters: Fisheries and Culture currently made entirely of ferrocement, and two types are built: the ‘box’ design (1.5 m long x 1.06 m wide x 13 cm high) (Fig. 23.lb), which is used mostly on hard bottoms, and the ‘caguamo’ design (1.6 m long x 1.22 m wide x 10 cm high) (Fig. 23.lc), which performs better on softer grounds. Old, deteriorated casitas of the ferrocement-trunk type, which have lost their trunk frame, are being recycled by lifting the ferrocement roof and bolting it over two sections of small construction trussed beams. The cost of casitas varies between US $35 and $45, depending on the materials employed. Casitas are typically placed on shallow (1-7 m) seagrass or algal beds, or over hard grounds; bare sand is avoided. When casitas were introduced, lobsters were first removed with bully nets. Later on, fishermen found it easier to dive down to the shelter and gaff the lobsters (Miller, 1982).Only the lobster tails were landed, and the heads were discarded. Skilled fishermen could estimate which lobsters were undersized and avoided gaffing them. Currently, however, the use of gaffs to extract lobsters from casitas is forbidden. If there is only a few lobsters beneath a casita, fishermen extract them with a bully net. When lobsters beneath a casira are abundant, fishermen encircle the casita with a seine net and lift one end of the casita with a pole. After disturbing the lobsters to force them out of the casita, they prod the lobsters into the conical end of the net and lift them into the boat. Undersized lobsters are returned to the water (Lozano-Alvarez et al., 1989). The abandonment of the use of gaffs in favour of bully or seine nets was triggered by the live-lobster industry, which has developed since the 1995/96 fishing season. Currently, about one-third of the lobster production in Bahia de la Ascensi6n is composed of live lobsters. After being caught, these lobsters are kept in cold running-water tanks to lower their metabolism, packed live in foam boxes of 10 kg capacity, containing wood shavings and artificial ice, and shipped to Asian countries, mainly Taiwan. Because of the higher value of live lobsters, it is expected that this industry will increase in the near future.

23.1.2

shelters

Hypotheses and current evidence of the mode of operation of artificial

The use of artificial reefs to increase fisheries production remains controversial because it is unknown whether these structures (1) provide critical resources that increase the environmental carrying capacity and eventually the biomass of reefassociated organisms (enhancement or production hypothesis), or (2) merely attract and aggregate organisms from surrounding areas without increasing total biomass (attraction hypothesis) (Bohnsack, 1989). If the enhancement hypothesis holds true, then artificial structures may provide a powerful means to mitigate the impacts of habitat loss or overfishing, and may also serve as an effective management tool to increase environmental carrying capacity and achieve sustainable resource use. Conversely, the attraction hypothesis implies that the use of artificial shelters could

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lead to overexploitation of the resource and eventual collapse of the fishery. The production-attraction hypothesis is extremely difficult to test experimentally at relevant spatial and temporal scales, and several recent reviews suggest that research efforts should instead focus on the function of artificial reefs (Bohnsack et al., 1997; Lindberg, 1997; Seaman, 1997). To ascertain whether or not artificial reefs enhance the production of reef inhabitants requires direct evidence of increased total regional catch or standing stock in proportion to the amount of artificial reef material deployed, while accounting for fishing effort, recruitment from surrounding areas and changes in year class strength (Bohnsack, 1989; Bohnsack et al., 1997). Suggested mechanisms underlying the enhancement hypothesis include: 0 0 0 0 0

increased feeding efficiency by the placement of shelters near foraging grounds provision of a refuge from predation provision of additional food provision of habitat for settling individuals that would otherwise have died or been eaten creation of space vacated by individuals moving to artificial reefs, which allows replacement by new recruits from outside the system (Bohnsack, 1989; Pickering & Whitmarsh, 1997, and references therein).

Conversely, artificial reefs that primarily concentrate individuals may potentially cause overharvest or fishery collapse by increasing the catchability of individuals normally dispersed over a wide area, particularly under high fishing pressure. The species most likely to benefit from the introduction of artificial reefs in terms of increased local biomass include obligatory reef species such as spiny lobsters. Relatively few studies have examined the concentration versus attraction hypothesis using spiny lobsters, particularly P . argus. Davis (1985) found that juvenile P . argus in Biscayne Bay, Florida, USA, merely moved from natural habitats to concrete block shelters with the introduction of the latter, with no increase in production. Cruz et al. (1986) found high colonization by early juvenile P . argus to concrete blocks in Cuba and inferred that lobster biomass increased owing to decreased predation-induced mortality. The studies by Davis (1985) and Cruz et al. (1986) were constrained by their lack of experimental controls and replication. Recently, several replicated experimental studies have addressed the production versus enhancement hypothesis with P . argus with mixed results. Working in macroalgal-dominated nursery areas within Florida Bay, USA, Butler & Herrnkind (1997) manipulated lobster settlement and shelter for juveniles.The number of small juvenile P . argus [<35 mm carapace length (CL)] increased significantly at six 0.05 ha sites where 12 artificial shelters, consisting of two stacked construction blocks, were added, but was unchanged on three unmanipulated sites. Adding over 150 new settlers to three of the shelter-enhanced sites did not increase juvenile lobster abundance above that attributed to shelter enhancement alone. A concurrent markrecapture study indicated that the observed increase in small lobster abundance in

424 Spiny Lobsters: Fisheries and Culture

the shelter-enhanced sites was not due to immigration (Butler & Herrnkind, 1997). These results support the notion that local recruitment of P. argus may be increased by augmenting natural shelter with appropriately designed artificial shelters (Butler & Herrnkind, 1997). In a related study in Florida Bay, Lipcius & Eggleston (unpubl. data) found that the abundance of P. argus increased in proportion to the numbers of casitas deployed, with no change in lobster abundance over time in control sites lacking casitas. Night-time band transects indicated that significantly more lobsters foraged within 1-ha sites containing casitas than in control sites. Thus, lobsters did not exploit available food resources in the control areas where shelter appeared limited. Lipcius & Eggleston (unpubl. data) concluded that shelter availability was limiting the abundance of juvenile P . argus in Florida Bay seagrass and macroalgal systems, and the use of casitas, combined with sensible management practices, would enhance lobsters fisheries production in this system. In a reef lagoon at Puerto Morelos, Mexico, where casitas had never been used, Lozano-Alvarez et al. (1998; unpubl. data) monitored the monthly density of juvenile P. argus (12.0-56.5 mm CL) throughout 12 months in nine 1 ha sites throughout the lagoon, prior to a controlled introduction of casitas. The lagoon is dominated by seagrass and a vast array of macroalgae. The sites were separated from each other by at least 200 m. In five sites, the density of juveniles was consistently close to zero, whereas in the remaining four, monthly density varied from two to 3 1 juveniles/ha. Tagged juveniles in any given site were never recaptured in other sites and movements recorded never exceeded 40 m. Because post-larval influx into this lagoon, as recorded monthly in artificial collectors since 1990, is high (BrionesFourzan, 1994; Briones-Fourzhn et al., 1998) and food for juvenile lobsters was abundant throughout the lagoon (Briones-Fourzh & Estrada, 1998; Castaiieda, 1998a), Lozano-Alvarez et al. (1998) hypothesized that a shortage of natural shelters was limiting juvenile abundance in the lagoon. Further on, 10 casitas were deployed in each of three ‘non-lobster’ and two ‘lobster’ sites, and the rest were left as controls. Juvenile density was then monitored bimonthly for an additional year. The results indicated a significant increase in the density of juveniles, in both the ‘non-lobster’ and in the ‘lobster’ sites, whereas density in control sites remained similar to previous values. Therefore, a bottleneck effect caused by the lack of proper shelters was proven in this reef lagoon. In the Exuma Cays, Bahamas, the results from the experimental manipulation of casitas were strikingly different than those observed in Florida Bay and in Puerto Morelos. Although lobster abundance was significantly higher in casita than in control sites, the casitas appeared primarily to concentrate relatively large juveniles (40-75 mm CL) that were migrating from inshore nursery areas to offshore patch reefs (Eggleston & Lipcius, unpubl. data). Lobster abundance in casitas was approx. 7-10% of that observed in Florida Bay (Eggleston & Lipcius, unpubl. data). The most likely explanation for the apparent difference in the function of casitas in Florida Bay versus the central Bahamas probably involves low settlement substrate

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availability for incoming post-larvae. For example, relative rates of post-larval settlement, as measured with floating, artificial settlement substrates, were similar between Florida Bay and the central Bahamas (Acosta et al., 1997; Eggleston et al., 1998; Eggleston, unpubl. data). The density of known settlement substrate such as complex macroalgae (Laurencia spp.), however, was extremely low or absent in most potential nursery areas in the Exuma Cays (Eggleston & Lipcius, unpubl. data). Eggleston & Lipcius (unpubl. data) concluded that available settlement substrate in Exuma Cays was generally below that at which the local population of P. argus might be limited by shelter. The contrasting results in the ecological function of casitas between Florida Bay and Puerto Morelos on the one hand, and the central Bahamas on the other, as well as recent evaluations of casitas and concrete block shelters for P. argus in various areas of Mexico (Lozano-Alvarez et al., 1994; Arce et al., 1997; Sosa-Corder0 et al., 1998), highlight the importance of considering habitat features in the successful application of artificial reef technology to fisheries enhancement.

23.2 23.2.1

Habitat features and ecology of spiny lobster in Bahia de la AscensMn Habitat features

Bahia de la Ascensibn is a large, open, shallow bay (about 740 km’) located within the Sian ka’an Biosphere Reserve in the state of Quintana Roo, on the Yucatan peninsula (19’45’N, 87’30’W; Fig. 23.2). The bay is surrounded by mangrove and wetlands. Several coral banks follow an ancient shoreline along the mouth of the bay, forming an interrupted reef. This coral reef reduces wave surge, resulting in relatively calm waters throughout most of the year (Lozano-Alvarez et al., 1991). The inner half of the bay is very shallow (<2 m) and the bottom is covered primarily with sparse seagrass patches (Thalassia testudinum) interspersed among coarse calcareous sand and coral rubble (Eggleston et al., 1990). The coral rubble is covered mostly by green and red algae (Dasycladus spp. and Laurencia spp., respectively). A thin sediment layer overlies a limestone foundation. The subtidal littoral fringe of the inner bay contains a band of detached clumps of Laurencia; this algal band probably serves as one of the major settlement habitats for pueruli entering this system. The inner bay is generally inhabited by small juvenile lobsters (9-90 mm CL, Eggleston et al., 1990; Lozano-Alvarez et al., 1991). The outer half of the bay is dominated by hard, sandy substrates and patch corals interspersed among moderate to dense seagrass beds (Thalassia testudinum) and calcareous algae, including Halimeda spp., Udotea spp. and Penicillus spp. Seagrass and algal habitats within Bahia de la Ascensibn provide the natural daytime refuge for juvenile P. argus in this system. The outer half of the bay is inhabited by large juvenile and adult lobsters (25-1 15 mm CL) (Eggleston et al., 1990; Lozano-Alvarez et al., 1991).

426 Spiny Lobsters: Fisheries and Culture

Fig. 23.2 (a) The coast of Quintana Roo, showing the main fishing localities for Panulirus urgus; (b) I-VI: sampling zones for tagging operations in Bahia de la Ascensibn. From LozanoAlvarez et al. (1991).

The coral reefs perpendicular to the mouth of the bay are inhabited by adult lobsters (70-172 mm CL) (Camarena-Luhrs et al., 1996; Eggleston, unpubl. data). Further offshore, at depths of 20-40 m, there are large juvenile and adult lobsters (52-162 mm CL) (Lozano-Alvarez et al., 1993). These observations are consistent with the known habitat requirements of different life-history stages of P. argus in other areas (see Kanciruk, 1980).

Population structure, growth and movements of lobsters in Bahia de la Ascensidn

23.2.2

Several population characteristics of P. argus in Bahia de la Ascensibn were studied by Lozano-Alvarez et al. (1991) and Lozano-Alvarez (1992). In six zones covering part of the inner and outer bay (Fig. 23.2b), 4800 undersized lobsters were tagged, of which 1250 were recaptured by fishermen in the following season, indicating a high rate of fishing mortality. Only 10 of the 2500 females showed signs of reproductive activity, and these were found in zones I1 and V (i.e. close to the reef). These results indicated that the population of lobsters in the bay consisted primarily of juveniles and subadults, which move outside the bay as they grow. The abundance and the size of the lobsters off the reefs, at depths of 20-40 m, differed significantly between

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summer and winter, indicating possible migrating pulses from within the bay (Lozano-Alvarez et al., 1993). Growth of juveniles within the bay is rapid. Allowing for a mean larval period of 6 months, males and females enter the fishery [135 mm tail or abdominal length (AL)] at approximately 2.15 and 2.2 years of age, respectively (Lozano-Alvarez et al., 1991). Because no fishing is exerted in the waters deeper than 15 m off Bahia de la Ascensibn, it is hypothesized that the continental shelf area in front of Bahia de la Ascensibn provides a refugium in space for reproductive lobsters (Lozano-Alvarez et al., 1993), as has been suggested for Homarus americanus in some parts of the Canadian coast (Anthony & Caddy, 1980; Campbell, 1989; Ennis & Fogarty, 1997).

23.2.3

Food and feeding

A seasonal study showed that juvenile P . argus fed largely on small crustaceans and gastropods throughout the year, with small amounts of other animal groups and plant material (Castaiieda, 1998). A tagging study of nocturnal foraging habits of juvenile P . argus in Bahia de la Ascensibn was conducted in the spring of 1991 (Ramos-Aguilar, 1992). Juveniles left the casitas at night to forage individually on the surrounding seagrass and sand flats. Feeding activity began at dusk and increased after 22:OO h. Juveniles foraged near the casita that they were occupying during the first few hours of darkness, and extended the foraging area later in the night. Not all lobsters under a casita would forage every night, a behaviour probably related to moulting (Lipcius & Herrnkind, 1982). Foraging movements were random, and although some juveniles returned to the same casita, others sought refuge in nearby casitas. The nocturnal foraging range of lobsters sometimes exceeded the limits of the surveyed area (about 12 ha), and some lobsters were recaptured at distances of 200-400 m only 1 day after being tagged. Lozano-Alvarez (1995) suggested that, in this bay, casitas allowed juvenile lobsters to exploit food resources successfully over extended areas by providing them with scattered shelters of similar size and shape throughout a large area, and thus reducing the exposure of juveniles during their foraging excursions.

23.2.4

Patterns of post-larval settlement on artificial collectors

A programme to monitor levels of post-larval influx into Bahia de la Ascensibn was started in 1987. An artificial surface collector was designed and tested for several key features, including cost of construction, efficiency and durability (Gutitrrez et al., 1992). After a 2-year survey for spatial and temporal settlement patterns (BrionesFourzPn & GutiCrrez, 1991, 1992; Briones-Fourzan, 1993) one site was selected for a long-term monitoring study, which is still underway.

428 Spiny Lobsters: Fisheries and Culture Pueruli enter the bay throughout the year, but variability is high. However, during most years there is a peak during the autumn (September-November) and a minimum in the winter months (Fig. 23.3). Variation in the annual index of pueruli settlement (mean number of pueruli per collector per year) from 1987 to 1998 has been high (1.50-5.51) (Briones-Fourzan, 1993, 1994, unpubl. data; Fig. 23.3). However, these values are low compared with other parts of the Quintana Roo coast (e.g. Puerto Morelos, 9.89-28.01 pueruli per collector per year; Briones-FourzLn, 1994, unpubl. data). Briones-Fourzan (1994) suggested that, in Bahia de la Ascension, the abundance of suitable habitats for pueruli settlement and subsequent juvenile growth allowed for the survival of the incoming post-larvae, and that the main factor regulating the abundance of juvenile P.argus in this bay was probably the variability in magnitude of pueruli recruitment.

Ecological role of artificial shelters

23.3

Casitas have been used in Bahia de la Ascension for nearly three decades but it has been impossible to test the enhancement versus concentration issue directly in this bay, because of a lack of quantitative information on the distribution and abundance of lobsters in the absence of casitas (Eggleston, 1991; Lozano-Alvarez, 1992).

5

0 iM7

1M

119

1690

+-Monthly

1691

1992

1993

199)

pueruli per collector +Annual

1995

lpPe

1997

1-

1888

index of settlement

Fig. 23.3 Indices of monthly post-larval settlement (mean catch of pueruli per collector) of Panufirus argus at Bahia de la Ascensibn, March 1987-June 1999, and annual average index of pueruli recruitment. From Briones-Fourzan (1993, 1994, and unpubl. data).

Research and Harvesting of Caribbean Spiny Lobsters

429

Experimental work in Bahia de la Ascensibn has now addressed one of the mechanisms underlying the production hypothesis - that artificial reefs provide protection from predators (Eggleston et al., 1990, 1992). Additional field experiments in this system have used casitas as a tool for examining the dynamics of lobster shelter selection under variable predation risk, social conditions and shelter size (Eggleston & Lipcius, 1992). Moreover, efforts are underway to examine the impact of casita-associated predators upon macrobenthic population dynamics and community structure (Eggleston, unpubl. data).

23.3.1

Patterns of survival

Increased predation pressure at or near casitas could outweigh the benefits from potential increases in production. For example, lobsters that were normally dispersed over a wide area could be concentrated by casitas and consumed by the local predator guild, which could also be concentrated by casitas. Tethering experiments were conducted in Bahia de la Ascension to examine the impact of different sized casitas, distance from casitas and lobster size class on survival of juvenile P. argus (Eggleston et a[., 1990, 1992). Observations indicated that the daytime predator guild, composed primarily of snappers (family Lutjanidae), seldom strayed more than 60 m from casitas and were typically within 15 m of casitas. In tethering experiments, spiny lobster survival was (1) higher in casitas than seagrass meadows 15 m away, irrespective of casita size; (2) generally higher in smaller than larger casitas, although the effect depended on the relationship between lobster and shelter size; and (3) higher for large (56-65 mm CL) than small (45-55 mm CL) juveniles tethered in seagrass 70 m away from casitas. The collective results from these tethering experiments (Eggleston et al., 1990, 1992) suggest that casitas in Bahia de la Ascensibn may increase lobster production through increased survivorship. Predator removal experiments conducted in the central Bahamas examined the effects of predation on the abundance of P . argus, reef fish and crabs inhabiting or residing near casitas placed in shallow (-3 m) seagrass meadows (Eggleston et al., 1997, 1998). These casitas concentrated high numbers of juvenile and adult Nassau grouper (Epinephelus striatus), as well as other potential lobster predators. A markrecapture study of Nassau grouper predators indicated high site fidelity, with no recorded movement of fish between casitas placed 30 m apart (Eggleston et al., 1997). The abundance of predatory grouper and the size of shelters from predation jointly explained the observed distribution and abundance patterns of spiny lobsters inhabiting casitas. For example, the abundance of small lobsters was highest in small reefs where Nassau grouper were experimentally removed (Eggleston et al., 1997). Eggleston et a f . (1990) proposed that several key physical properties of the casita that are likely to influence den choice and increase survivorship of P.argus are (1) a shaded cover provided by the wide roof; (2) low roof height, which excludes large

430 Spiny Lobsters: Fisheries and Culture

piscine predators; and (3) multiple den openings that are smaller than the inner roof height of the casita, which provide alternative escape routes and may facilitate social grouping with collective antipredator vigilance. However, large nurse sharks are often found in casitas in the wild, cohabiting with P . argus (Rios-Lara et al., 1995; Lozano-Alvarez, pers. observ.). Other smaller predators also cohabit with lobsters in casitas, but no attacks inside the casitas have ever been recorded. Based on experiments conducted with juvenile P . argus and a lobster predator (the triggerfish Balistes vetula) in enclosures provided with casitas, Lozano-Alvarez & Spanier (1997) concluded that casitas protect lobsters against fish predators, not because the latter are excluded from casitas, but because fish need open space to manoeuvre properly during their attack on the lobsters. The restricted vertical space inside a casita may prevent fish attacks and allow for cohabitation of prey and predator, both of which take advantage of the shade provided by the casita during the daytime.

23.3.2

Dynamics of den choice

Juvenile, subadult, and adult P . argus seek diurnal shelter following nightly foraging excursions. They often reside in crevices of rocky or coral reefs, in solution holes, under barrel sponges and branching octocorals, and beneath undercut seagrass banks (Forcucci et al., 1994; Lozano-Alvarez et al., 1998). Shelter use appears to be regulated by predation risk, the scaling between shelter and body size, the presence of conspecifics and familiarity with an area (Eggleston & Lipcius, 1992; Ratchford & Eggleston, 1998; Ratchford, 1999). These hypotheses were tested with a series of field enclosure experiments examining the effects of spiny lobster size, social condition (i.e. presence or absence of conspecifics), shelter size and predation risk (i.e. presence or absence of a nurse shark, Ginglyostoma cirratum, predator) upon den choice by juvenile and adult P. argus within Bahia de la Ascension, Mexico. To corroborate the findings from the enclosure experiments, seasonal size-specific abundance patterns of P. argus were quantified in Bahia de la Ascension by deploying casitas of different sizes in two habitats that differed primarily in the potential for gregarious habitation: an inner bay, sand seagrass flat with high lobster densities, and an outer bay, seagrass bed adjacent to coral reefs with sparsely distributed lobsters (Eggleston & Lipcius, 1992). The experimental and observational field results were similar: social condition and the scaling of lobster size to shelter size jointly regulated den choice patterns of adults and juveniles, particularly under high predation risk. When conspecific density and predation risk were low, lobsters resided primarily in scaled shelters; when conspecific density was high and predation risk was low, lobsters resided predominantly in large shelters offering the highest potential for gregariousness; when conspecific density and predation risk were high, lobsters shifted to gregarious habitation in smaller, scaled shelters; and when predation risk was high and conspecific density was low, lobsters occupied smaller shelters. In the field, large

Research and Harvesting of Caribbean Spiny Lobsters

43 1

casitus, which offer the highest potential for gregarious occupation with conspecifics, attracted significantly higher numbers and a broader size range of lobsters than medium or small shelters, particularly at the inner bay site where lobster densities were high. Medium cusitus were only effective at concentrating medium-sized juvenile lobsters at the outer bay site, while small cusitus were only occasionally inhabited by small juvenile lobsters. The frequency of gregariousness in the field was much higher at the inner bay site, where lobsters were numerous, than at the outer bay site, where lobsters were sparse, even accounting for the difference in lobster density between sites. These results indicated that the density of conspecifics in a given habitat can enhance gregariousness in spiny lobsters, which in turn influences the relative impact of lobster size, shelter size and predation risk upon den choice. In defining the critical determinants of den choice for P. urgus, Eggleston & Lipcius (1992) also provided an empirical and conceptual framework (Fig. 23.4) for identifying how variations in the availability of resources, such as conspecifics and appropriately scaled refuges, influence the distribution and abundance of social, shelter-dwelling species. A subsequent series of Y-maze and mesocosm shelter choice experiments, as well as a field mark-recapture study, were conducted in the central Bahamas. Ratchford & Eggleston (1998) and Ratchford (1999) examined the effects of conspecific odours, physical disturbance and familiarity with an area upon shelter fidelity in P. argus. In the field, lobsters returned to the shelter that they used the night before on 40% of occasions, a measure very similar to that displayed by P. urgus in other studies (Herrnkind et af., 1975). Lobsters that were unfamiliar with an area exhibited higher shelter fidelity than those with experience in an area (Ratchford, 1999). Physical disturbance, created by prodding lobsters from their shelters, had little effect on shelter fidelity among lobsters in Ratchford’s (1999) study. Conspecific scents emanating from a nearby shelter caused most lobsters to shift to that shelter. Conspecific scents appear to be important in shelter selection and shelter fidelity. Spiny lobsters may be using conspecifics as cues to locate a shelter and assess the ‘quality’ of a shelter, as described above. Results from a different field study also support the hypothesis that the local density of conspecifics can enhance gregariousness. During the closed season in 1985, 153 standard casitas in the six zones depicted in Fig. 23.3b were surveyed and the lobsters beneath each casita were counted. The overall distribution of lobsters per casita approached a Poisson distribution (Lozano-Alvarez, 1992; Fig. 23.5a), with 39.2% of casitas occupied by one to 10 lobsters. However, the number of lobsters per cusita differed according to site within the bay (Fig. 23.5b). Although these results were probably due to enhanced gregariousness owing to higher conspecific densities in certain zones, the mechanisms underlying these differences in lobster density between zones remain to be determined. Yet another study further demonstrated the importance of specific shelter features for den choice by juveniles in Bahia de la Ascension (Lozano-Alvarez et uf., 1994). The study was devised to test the assumption of the importance of shelter scaling and

432 Spiny Lobsters: Fisheries and Culture (a) Without predatorsllow predation risk

______

1 .o- mall shelters Proportional residency 0.5-

0-

z

large shelters

Low

limits set by shelter availability

,/

A

High

s= L Spiny lobster density

(b) With predatorslhigh predation risk

______ shelters Proportional residency

-

large shelters

Low

A

s= L

High

Spiny lobster density

Fig. 23.4 Model of the hypothesized relationship between shelter size, spiny lobster density and spiny lobster proportional residency in shelters. S, small shelter; L, large shelter. Although proportional residency is represented as a threshold (sigmoid) function at low to moderate lobster densities, the relationship between lobster density and proportional residency could also be represented as a linear increase (or decrease in small shelters) to an upper (lower) plateau, or as a hyperbolic increase (or decrease in small shelters) to an upper asymptote. From Eggleston & Lipcius (1992).

shelter properties for providing suitable dens for small ( 4 0 mm CL) and large ( > 50 mm CL) juvenile P . argus. The shelters, built with construction blocks, were categorized into four types. Shelter types 1 and 3 consisted of either 16 large (type 1) or 24 small (type 3) construction blocks, forming a quadrangular structure of eight blocks, with two and three layers of blocks, respectively, and an open central area. Shelter types 2 and 4 were similar to types 1 and 3, respectively, but with a plate covering the open central area. Three shelters of each type were deployed in each of eight sites in the bay and were investigated at irregular time intervals for 9 months. Shelters located close to the coral reef or in bare sand or sparsely vegetated areas attracted small numbers of large juveniles. Shelters deployed in an inner bay site (zone I11 of Fig. 23.2b)

Research and Harvesting of Caribbean Spiny Lobsters

r

433

(a)

40

30

0 6.Ascensi6n N = 153

Lc

0

a,

0) (II

60 2 a 50 40 a,

Zone II (N = 57)

0 ZonelV

(N=56)

30

20 10

n

0

Number of lobsters per casita Fig. 23.5 (a) Overall distribution of casita occupation (number of lobsters per casita) in the six sampling zones in Bahia de la Ascension, during April-May 1985 (total casitas surveyed: 153; total Panulirus argus found beneath casitas: 3955). (b) Distribution of casita occupation by lobsters in zone I1 (black bars) and zone IV (white bars) in Bahia de la Ascension, during April-May 1985 (total casitas surveyed in zone 11: 57; in zone IV: 56; total lobsters found beneath casitas in zone 11: 862; in zone IV: 2185). From Lozano-Alvarez (1992).

attracted high numbers of small juveniles. This site was located in a protected, moderate seagrass area known to contain high numbers of juvenile lobsters (LozanoAlvarez et al., 1991). Covered shelters did not significantly attract more lobsters, but showed less fluctuation in the number of residing lobsters throughout the study. Lozano-Alvarez et al. (1994) concluded that multiple den openings and a shaded cover were important features of communal dens for juveniles, but that, although block shelters were attractive to small juveniles, they only seemed to function adequately in areas where these juveniles were already concentrated. These results

434 Spiny Lobsters: Fisheries and Culture suggest that in addition to certain physical characteristics of the shelter, local habitat features may be important in determining the success of artificial shelters in attracting and concentrating lobsters. In a nursery area at Cayos Contoy, Quintana Roo, Arce et al. (1997) introduced scaled-down casitas in five sites differing in habitat structure and monitored the abundance of juvenile P . argus in these casitas for 12 months. These authors found that casitas were occupied mostly by size-specific groups of juveniles, influenced by the natural habitat type in each site: juveniles 16-35 mm CL occupied casitas placed on vegetated habitats, whereas larger lobsters (35-70 mm CL) occupied those deployed on hard grounds. In a concurrent study, Sosa-Corder0 et al. (1998) used normal-sized casitas in an additional six sites, differing in the relative availability of seagrass and hard bottom. Their results showed that seagrass availability was the determing factor in casita occupancy by lobsters (12.8-101.7 mm CL). Sosa-Corder0 et al. (1998) concluded that, for practical purposes, sites without, or distant from, habitats rich in lobster food (i.e. seagrass and algal beds) should be avoided when placing casitas.

23.4 23.4.1

Lobster production and management in Bahia de la Ascensibn Development of the fishery

Until 1992, fishing co-operatives in Mexico had exclusive rights to exploit eight fishing resources, among them spiny lobsters. In Quintana Roo, one fishing co-operative, based on the island of Cozumel, had the rights to fish for spiny lobsters in both Bahia de la Ascensibn and Bahia Espiritu Santo. As of 1968, a new co-operative based in Punta Allen was granted Bahia de la Ascensibn as its fishing ground. After the Federal Law for Fisheries was amended in 1992, fishing co-operatives lost exclusivity to fish for lobsters and currently they must apply for a concession to exploit fishing resources in a given area. The co-operative at Punta Allen has been granted a concession for 20 years to exploit all fishing resources in Bahia de la Ascensibn, between Punta Xamach and Punta Pajaros (Fig. 23. lb), including the coral reef in front of the bay and off the reef to a depth of 20 m. Because lobster is by far the most valuable fishing resource in this area, it is still the main target species for the fishers in the co-operative. However, owing to the fast development of tourism in the region, there are currently three touristic co-operatives in the bay area that take tourists for sport fishing. Members of the fishing co-operative can also be members of touristic co-operatives. The sport fishing season lasts from November to May, and fishers decide whether to fish for lobsters or to take tourists for sport fishing during that period. Casitas were first introduced into northern Quintana Roo in the late 1960s (Miller, 1982; Lozano-Alvarez et al., 1989), and extended to the bays of Ascension and Espiritu Santo by the early 1970s. The use of casitas as a ‘common-property’ resource resulted in the failure of this fishing technique in northern Quintana Roo

Research and Harvesting of Caribbean Spiny Lobsters

435

during the late 1970s. In contrast, fishermen in Bahia de la Ascension have devised a closed system, based on the division of the bottom of the bay into plots or parcels called campos, that has permitted the extended use of casitas in this area for more than 25 years. Campos warrant exclusive use of an area by a specific fishing team, thus precluding disputes over the ownership of casitas. During the spiny lobster closed season, fishermen construct new casitas and deploy them in their campos. It is up to the fishermen to construct as many casitas as they are willing to invest in each year. In 1985, there were approximately 20 000 casitas in the entire fishing grounds of Bahia de la Ascension (Lozano-Alvarez et al., 1991), but after hurricane Gilbert (14 September 1988), the number of casitas was reduced to about 10 000. In July 1999, there were 16 950 casitas. 23.4.2

Fishing regulations and enforcement

Regulations for the fishery of spiny lobsters in Quintana Roo include a minimum legal size (MLS), a closed season and a prohibition on the capture of egg-bearing females. Only lobster tails were commercialized, and therefore, the MLS was considered as tail length ( = AL) Up to 1978, the MLS for P . argus throughout Quintana Roo was 145 mm AL. However, in 1979, the fact that casitas in the shallow bays of Ascension and Espiritu Santo basically attract immature individuals was recognized by the fisheries managers, and led to a reduction in the MLS for spiny lobsters in both bays, from 145 to 135 mm AL. Socioeconomic factors also influenced this decision, including the higher market value of small lobsters and the need to maintain a profitable fishery for the co-operatives of the central coast of the state. The MLS for the rest of the coast (145 mm AL) remained effective until 1998, when it was also reduced to 135 mm AL. Up to 1987, the closed season was from 16 March to 15 July, but in early 1988, fishermen throughout Quintana Roo claimed that bad weather during the winter months had reduced their effective fishing days and applied for an extension of the fishing season. The fishing authorities agreed, and in 1988 the closed season lasted only from 8 April to 30 June. Since 1989, the closure has been from 1 March to 30 June. In addition to the official regulations, members of the co-operative are expected to respect the boundaries of each other’s campos. Fishing in someone else’s campo is considered a major offence; the penalty for this is severe, and can result in ejection from the co-operative. 23.4.3

Catch, fishing effort, and CPUE trends

The lobster catch from Bahia de la Ascension accounts for 17% of the total catch of the state of Quintana Roo and the local co-operative has the second highest catch of the 19 in the state.

436 Spiny Lobsters: Fisheries and Culture The total catch of lobster tails in Bahia de la Ascensibn between the 1975/76 and the 1998/99 fishing seasons is shown in Fig. 23.6. Data from 1995 onwards included lobster tails and whole live lobsters. Live lobster weight was transformed to tail weight with the equations provided by Lozano-Alvarez (1992). The maximum catch in this period (71.2 t) was obtained in 1979/80. In 1987/88, a second peak in production (65.7 t) was reached, followed by a sharp decrease, with the lowest recorded catch (19.6 t) in 1996/97. On 14 September 1988, Hurricane Gilbert (category 5 in the Saffir-Simpson scale) struck the coast of Quintana Roo. Fishermen in Bahia de la Ascensibn claim that they lost up to 50% of their casitas owing to the hurricane. In addition, vast areas of the bay were disturbed by the wave surge, which may also have had some effects on the lobster population inside the bay (Lozano-Alvarez, 1992). Fishermen blame Hurricane Gilbert for the reduction in lobster catch during 1990/91 and further on, both within Bahia de la Ascensibn and at numerous other locations within the state. However, other factors may help to explain the dramatic drop in landings during 1990/91 (Briones-Fourzan & Lozano-Alvarez, 1992), such as (1) the shorter closed season in 1988; and (2) the low indices of pueruli recruitment obtained in Bahia de la Ascensibn in 1987/88 (Briones-Fourzkn, 1993; see Fig. 23.3). Nevertheless, catches have remained low since 1990, despite the fact that the number 80

70

z

60

0 -

X

0

50

Y,

2 40

3

L

n

30

0

20

a

~

~

a

r

n

~

~

o

a

-

~

q ~q a e s~ s s s f

I

Fishing season

Fig. 23.6 Production (t of lobster tails) of Panufirus argus in Bahia de la Ascension, fishing seasons 1975/76 to 1998/99. Sources: Delegaci6n Federal de Pesca en Quintana Roo, Cooperativa ‘Pescadores de Vigia Chico’.

~

Research and Harvesting of Caribbean Spiny Lobsters

437

of casitas has increased again to almost pre-1988 levels. It is possible that a recruitment failure, caused by unknown factors, occurred between 1988 and 1990. However, there are no data on pueruli settlement prior to 1987 so, even though annual settlement indices have increased since 1988 (Fig. 23.3), it is impossible to know whether these indices were at a different, higher level, before 1987. Annual trends in the catch per unit effort (CPUE; catch per boat per day) have been similar since the 1981/82 fishing season. Within any year, the highest CPUE occurs during the first month after the opening of the season, followed by a sharp decline over the next few months (Lozano-Alvarez et al., 1991 and unpubl. data). This trend probably reflects both fishing and natural mortality, as well as emigration. A similar decline in CPUE from the beginning until the end of the fishing season has been reported for other P . argus fisheries (Warner et al., 1977; Lyons et al., 1981), but in the case of Bahia de la Ascension, the decline from the first to the second month of the season is sharp (e.g., July 1998 CPUE: 27.5 kg tails per boat per day; August 1998 CPUE: 19 kg tails per boat per day). It is possible that in the absence of fishing mortality during the closed season, the aggregation effect of casitas on juvenile spiny lobsters may result in a higher catch per casita during the first month of the season than in the remainder of the season (Lozano-Alvarez el al., 1991). Arceo & Seijo (1991) attempted to identify factors that may have influenced the spiny lobster catch per casita in the 1987/88 fishing season. Factors introduced in their multiple regression analysis were effective fishing time (in hours), number of crew members, fishing depth and number of casitas checked. When the analysis was broken down by month, there was a significant correlation between catch and fishing time, as well as the number of crew members. Seijo et al. (199 1) estimated a mean catch of 11.6 kg of lobster tails per fishing trip and a mean of 6.5 fishing days per month in Bahia de la Ascension, throughout the 1987/88 fishing season, with the highest values at the beginning of the season and the lowest values during December. Lozano-Alvarez (199 1) found a positive relationship between the fishing effort (number of fishing trips per day) and the CPUE (catch per boat per day), and concluded that this indicated that fishermen increase their effort when lobster abundance is high and, conversely, that they shift to other activities when lobster abundance is reduced. A bioeconomic analysis, which allowed the net return by fishing boat to be derived specifically for each of four fishing methods (diving, traps, nets and casitas), was performed by Seijo et al. (1991). These authors concluded that the use of casitas in delimited areas, versus more traditional harvesting methods, yielded the highest net returns, meaning that this casita-based fishing method is highly efficient.

23.4.4

Fisheries problems and alternatives

The local co-operative has a limit to the number of members, which can be considered a form of limited entry. The maximum number allowed is 108, but in

438 Spiny Lobsters: Fisheries and Culture 1999 there were only 80 members. Currently, only the children of former members may become new members. Limited entry has facilitated sustainable use in other spiny lobsters fisheries (e.g. Panulirus cygnus in Western Australia, Bowen & Hancock 1989; for a review, see Briones-Fourzan, 1991); however, it does not necessarily imply a limit in fishing effort (Bowen & Hancock, 1989). For example, although the number of fishermen has decreased in the last few years, they have ways of enhancing their fishing performance, through faster boats, better materials for the construction of casitas and the deployment of more casitas between fishing seasons. These variables affect the fishing effort and should be taken into account in future estimates of CPUE. The time series of puerulus settlement is currently long enough to explore its relationship with the catch. However, the relationship is not clear (Lozano-Alvarez & Briones-Fourzan, 1996). The lack of such a predictive capability has proved nearly fatal to the economic infrastructure of the fishery in Bahia de la Ascension. Because of the relatively high landings between 1979 and 1988, the fishermen assumed that they had reached a level of exploitation sufficient to back financially the application for a large sum of money to build an expensive, large, modern processing plant. After the plant was completed, in 1989, the lobster production in the bay and elsewhere declined dramatically (Fig. 23.6), making the operation of the plant unprofitable. By late 1991, the co-operative was unable to pay the debt and the plant was repossessed by the bank. Since then, the plant has been concessed to other proponents, but it has remained unprofitable and currently it is unused. Predictive models such as those that have been employed in Western Australia (Phillips, 1986) may have forecasted the very low catches obtained during the 19891996 seasons. Thus, although there is little doubt that casitas facilitate lobster harvest, both a longer time-series of annual pueruli influx, and especially a reliable measure of effort, are issues that need to be addressed in future management recommendations.

23.5 23.5.1

Perspectives on the use of artificial structures for spiny lobster fisheries

Future research needs

The main impediment precluding a solution to the problem of artificial shelter enhancement versus concentration concerns the lack of rigorous ecological experiments that test the two hypotheses, particularly experiments derived from conceptual models unifying the various critical components producing variation in recruitment (e.g. Rotschild, 1986, pp. 129-33). Although the progress recently achieved in a few issues related to this problem has been stressed, many other issues remain poorly understood. Future research on the impact of artificial reefs upon spiny lobster population dynamics at the local scale will require intensive, long-term monitoring of post-larval settlement, cohort density, growth and survival in

Research and Harvesting of Caribbean Spiny Lobsters

439

experimental and control habitats. Further ecologically based field experiments are required to determine the range of habitats capable of supporting enhancement through the addition of artificial shelters or other limiting resources (e.g. settlement habitat). Some indirect evidence supporting increased lobster production with artificial reefs could be provided by experimentally demonstrating the increased growth and survival at artificial reefs (e.g. Bohnsack, 1989). Research is also needed on the scale at which enhancement may be operating. The best direct evidence proving increased lobster production at a larger scale could be an increased total regional catch or standing stock in proportion to the amount of reef material deployed, while controlling for fishing effort, attraction from surrounding areas and changes in year class strength (Bohnsack, 1989; Bohnsack et al., 1997). Experimental studies are needed to determine which factors or combination of factors are important in the success or failure of artificial shelters. Such studies should determine optimum casita size, design (e.g. variations in the number of casita openings), density and placement. The use of artificial lobster reefs in marine sanctuaries (e.g. in seagrass and algal nursery habitats) to improve growth and survival of juveniles should also be examined. For example, the placement of casitas in food-rich seagrass beds allowed the exploitation of available food resources by lobsters (Ramos-Aguilar, 1992; SosaCorder0 et al., 1998) and concurrently reduced foraging distances to these areas (Lipcius & Eggleston, in press). These results suggest that growth rates should be higher in shelter-enhanced habitats. Moreover, given the relative importance of conspecific and shelter size to observed dynamics of spiny lobster survival (Eggleston et al., 1990) and shelter selection (Eggleston & Lipcius, 1992; Lozano-Alvarez et al., 1994), commercial harvesting of large juvenile and adult lobsters from nursery areas should be viewed with caution. Reduced conspecific densities in fished areas might cause small juvenile lobsters to search for and occupy a more limited range of shelters in the absence of the increased protection afforded by gregarious residency (Eggleston & Lipcius, 1992). Hence, predation-induced mortality rates of juvenile lobsters may be higher in fished areas than in protected areas. These hypotheses should be tested. Casitas are placed on vegetated areas to ensure good catches and to avoid the filling of the space beneath the casita with sand. The short- and long-term impacts of placing a high number of casitas on the benthic communities associated with seagrass, and on the stability and structure of the seagrass beds, are aspects that also need to be researched (Lozano-Alvarez et al., 1991). Efforts addressing these aspects are currently underway (Briones-Fourzhn et al., unpubl. data).

23.5.2

Application of technology to other geographical areas

Interest in the application of casitas for harvesting or enhancing lobster production is steadily increasing throughout the Caribbean as well as outside the Caribbean, in

440 Spiny Lobsters: Fisheries and Culture such areas as Bermuda (Evans et al., 1995), Israel (D.L. Miller, pers. comm.), Kenya (Okechi & Polovina, 1995) and Australia (B.F. Phillips, pers. comm.). For instance, in the Bahamas over the past 2-3 years, casita use has expanded dramatically, with conservative estimates yielding over 200 000 casitas in the northern Bahamas alone. The sudden adoption of an unconventional and novel mode of fishing - based on artificial shelters rather than traps - portends an unprecedented change in the character of the Caribbean spiny lobster fishery (Lipcius & Eggleston, in press). This transformation could lead either to a long-term sustainable resource use of the most valuable fishery in the Caribbean, or to a decline and eventual collapse of the fishery, with far-reaching consequences for all Caribbean nations. Casitas are very effective at concentrating spiny lobsters because of the gregarious nature of these species (Eggleston & Lipcius, 1992). Hence, without appropriate management regulations, such as closed-access fisheries (e.g. casitalcampo system) and minimum size limits for fishery capture, the use of casitas could lead to growth overfishing or recruitment overfishing, which produce submaximal yields and decline of the spawning stock, respectively (Pitcher & Hart, 1982). An additional preventive measure in this scenario would entail the deployment of casitas in sanctuaries as described above, thereby precluding the impact of harvesting. A different scenario, involving novel mechanisms of population control, could take place (Lozano-Alvarez, 1992). Fishermen throughout Quintana Roo and Yucatkn had requested, for over 10 years, the unification of the minimum size of P . argus for the whole fishery to that allowed in Bahia de la Ascensi6n (135 mm AL), on the grounds that it was unfair for the non-bay fishers to constrain their catch to lobsters over 145 mm AL, i.e. reproductive adults, which were less abundant. Fishing authorities were initially reluctant, invoking a possible recruitment overfishing, but finally, in 1998, they agreed to this reduction. The management strategy of exploiting the reproductive sector of a stock has been conventionally applied to a number of fishing resources, particularly piscine species, and is expected to maximize catch biomass and to ensure that individuals have at least one opportunity to reproduce. Hence, the underlying assumption of this strategy is some form of stock-recruitment relationship (SRR), a poorly known issue for most crustaceans, because environmental factors play a major role in determining spawning success and larval survival, and usually overwhelm any SRR present (Cobb & Caddy, 1989), although some evidence of its existence has been provided for Homarus americanus (Fogarty & Idoine, 1986; Ennis & Fogarty, 1997) and some shrimp species (Penn et al., 1989; Gracia, 1991). Alternatively, the SRR may be obscured by either favourable or unfavourable environmental conditions at the time of post-larval recruitment (Fogarty et al., 1991; Gracia, 1991). In addition, the catch of the most successful lobster fisheries in the world (i.e. P . cygnus in Western Australia, Bowen & Hancock, 1989; P . argus in Cuba, Cruz et al., 1987; and H. americanus in Canada, Campbell, 1989) includes a high percentage (> 50%) of newly recruited juveniles and subadults. In the case of H . americanus, the dramatic increase in landings during the 1980s challenged the traditional fisheries

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models based on concepts such as surplus production and stable recruitment (Elner & Campbell, 1991), and led to a revision of the recruitment overfishing reference points for this fishery (Ennis & Fogarty, 1997). This phenomenon seems more akin to the current supply-side paradigm where recruitment levels, controlled by unpredictable climatic phenomena, can change internal regulations normally operating within a system (Lewin, 1986; Underwood & Fairweather, 1989). Large environmental forces also are responsible for recruitment variations in P . cygnus (Phillips et al., 1991), and possibly in many other marine species with a complex life history (Fogarty et al., 1991). Thus, a different fishing strategy would involve intensively exploiting young recruits, and protecting nuclei of the spawning stock by means of refugia in space (i.e. spawning areas) or time (i.e. closed seasons) (Anthony & Caddy, 1980; Campbell, 1989; Ennis & Fogarty, 1997). This type of strategy has been effectively, if empirically, applied in Bahia de la Ascensibn, and in Cuba, through the use of casitas as fishing tools in nursery areas, and an absence of fishing in deeper, spawning areas (Gonzalez et al., 1991; BrionesFourzhn & Lozano-Alvarez, 1992; Lozano-Alvarez, 1992, 1994), in addition to a closed season during which some of the juveniles reach the critical size to exit the nurseries and move to the spawning areas (Lozano-Alvarez et al., 1991, 1993). A similar situation occurs in Western Australia, where the Abrolhos Islands, an important spawning ground with a fishing season shorter than in the mainland, provide a significant refugium in space for P . cygnus (B.F. Phillips, pers. comm.). However, the recent expansion of the use of casitas in other coastal areas of Quintana Roo should be closesly monitored to assess its effects on the whole fishery. In north-eastern Quintana Roo, around Isla Mujeres (see Fig. 23.2a) the fishery for P . argus has historically been the most intensive in the state. Five fishing cooperatives operate in this area and fishers use every possible method to extract lobsters from shallow areas to depths of over 60 m (Lozano-Alvarez, 1994). Since 1995, casitas have been introduced in the mainland shallow nurseries, which were the only habitats not fully exploited before. Because of the recent reduction in the MLS, the catch in north-eastern Quintana Roo now encompasses lobsters from small subadults to the largest adults in the fishery. In addition, the tremendous growth of the tourist industry in the same area, with the concurrent increase in coastal construction and modification, is endangering the shallow habitats where pueruli settle and small juveniles dwell. Given the high levels of fishing effort, the disparate techniques employed in this area, the impact on juvenile habitat and the low levels of lobster catch during the 1990s, the uncontrolled introduction of casitas in this area may contribute to overfishing in the long term, unless strict regulations are rapidly implemented. The issue is complex, and the application of casitas as a fishing technique elsewhere will not be successful unless key biological, habitat and management requirements are met. In the case of P . argus, Lozano-Alvarez (1995) suggested that the minimum biological and habitat requirements for successful use of casitas were an adequate supply of post-larval recruits, settlement habitat and food, shallow

442 Spiny Lobsters: Fisheries and Culture seagrass and hard bottoms, low water turbidity, and a lack or scarcity of adequate natural shelters. The minimum management requirements would be a system that ensures property of the casitas (such as the camp0 system), a sufficiently long closure each year to allow the recovery of the population and the exit of adult lobsters to unfished deeper habitats, the protection of habitats for pueruli settlement and juveniles, a strict control on fishing effort on adult populations in deep habitats, and an adequate minimum size to allow for a sufficient catch level without overfishing the resource (Lozano-Alvarez, 1995).

References Acosta, C.A., Matthews, T.R. & Butler, M.J. IV (1997) Temporal patterns and transport processes in recruitment of spiny lobster (Panulirus argus) postlarvae to south Florida. Mar. Biol., 129, 79-85. Anthony, V.C. & Caddy, J.F., Eds. (1980) Proc. Canada-US. Workshop on status of assessment science for N.W. Atlantic lobster (Homarus americanus) stocks. Can. J . Fish. Aquat. Sci., Tech. Rep., 932, 186 pp. Arce, A.M., Aguilar-Davila, W., Sosa-Cordero, E. & Caddy, J.F. (1997) Artificial shelters (casitas) as habitat for juvenile spiny lobsters Panulirus argus in the Mexican Caribbean. Mar. Ecol. Prog. Ser., 158, 217-24. Arceo, P. & Seijo, J.C. (1991) Fishing effort analysis of the small-scale spiny lobster (Panulirus argus) fleet of the Yucatan shelf. FA0 Fish. Rep., No. 431, 59-74. Bohnsack, J.A. (1989) Are high densities of fishes at artificial reefs the result of habitat limitation or behavioral preference? Bull. Mar. Sci., 44, 631-45. Bohnsack, J.A. & Sutherland, D.L. (1985) Artificial reef research: A review with recommendations for future priorities. Bull. Mar. Sci., 37, 11-39. Bohnsack, J.A., Eklund, A.M. & Szmant, A.M. (1997) Artificial reef research: is there more than the attraction-production issue? Fisheries, 22, 14-16. Bowen, B.K. & Hancock, D.A. (1989) Effort limitation in the Australian rock lobster fisheries. In Marine Invertebrate Fisheries: Their Assessment and Management (Ed. by J.F. Caddy), pp. 37593. Wiley Interscience, New York, USA. Briones-Fourzan, P. (1991) Marco teorico de la regulacion pesquera en langostas. In Taller regional sobre manejo de la pesqueria de la langosta (Ed. by P. Briones-Fourzan). Inst. Cienc. del Mar y Limnol. Univ. Nal. Autdn. MPxico. Publ. TPcn., 1, 1-10. Briones-Fourzan, P. (1993) Reclutamiento de postlarvas de langosta Panulirus argus (Latreille, 1804) en el Caribe mexicano: patrones, posibles mecanismos e implicaciones pesqueras. Tesis Doctoral, Fac. Ciencias, Univ. Nal. Auton, MCxico, 140 pp. Briones-Fourzan, P. (1994) Variability in postlarval recruitment of the spiny lobster, Panulirus argus (Latreille, 1804) to the Mexican Caribbean coast. Crustaceana, 66, 32WO. Briones-Fourzan, P. & Estrada, J.J. (1998) Fauna bkntica en zonas de vegetacion marina en la laguna arrecifal de Puerto Morelos. In Funcionamiento de refugios artificiales para langosta y su impact0 en habitats de pastizal marino (Ed. by P. Briones-Fourzin), pp. 76120. Informe Final, UNAM-CONACYT, I171-N, MCxico. Briones-Fourzan, P. & Gutierrez, D. (1991) Variaciones en el patron de reclutamiento de postlarvas de la langosta Panulirus argus en Bahia de la Ascension, Mkxico. Rev. Inv. Mar. (Cuba), 12(1-3), 45-56.

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Briones-Fourzan, P. & Gutierrez, D. (1992) Postlarval recruitment of the spiny lobster, Panulirus argus (Latreille, 1804), in Bahia de la Ascension, Q.R., MBxico. Proc. GulfCarib. Fish. Znst., 41, 492-507. Briones-Fourzin, P. & Lozano-Alvarez, E. (1992) La langosta en Bahia de la Ascension. Asociacidn de Amigos de Sian Kahn. Serie Cuadernos de Sian Ka’an, No. 3, 16 pp. Briones-Fourzan, P., Lozano-Alvarez, E. & Negrete-Soto, F. (1998) Reclutamiento de postlarvas (puerulos) de Panulirus argus en la laguna arrecifal de Puerto Morelos. In Funcionamiento de refugios artificiales para langosta y su impact0 en habitats de pastizal marino (Ed. by P. BrionesFourzbn), pp. 12142. Informe Final, UNAM-CONACYT, 1171-N, Mexico. Butler, M.J., IV & Herrnkind, W.F. (1997) A test of recruitment limitation and the potential for artificial enhancement of spiny lobster (Panulirus argus) populations in Florida. Can. J . Fish. Aquat. Sci., 54, 45243. Camarena-Luhrs, T., CobCCetina, L., Aguilar-Perer, A. & Aguilar-Davila, W. (1996) Densidad y abundancia de juveniles de langosta (Panulirus argus) en Bahia Ascension, Quintana Roo, Mexico. Proc. Gulf Carib. Fish. Inst., 44,579-93. Campbell, A. (1989) The lobster fishery of southwestern Nova Scotia and the Bay of Fundy. In Marine Invertebrate Fisheries: Their Assessment and Management (Ed. by J.F. Caddy), pp. 14158. Wiley Interscience, New York, USA. Castaiieda, V. (1998) Alimentacion natural de los juveniles de la langosta Panulirus argus (Latreille, 1804). Tesis profesional, Fac. Ciencias, Univ. Nal. Auton. Mexico, 67 pp. Cobb, J.S. & Caddy, J.F. (1989) The population biology of decapods. In Marine Invertebrate Fisheries: Their Assessment and Management (Ed. by J.F. Caddy), pp. 327-74. Wiley Interscience, New York, USA. Conan, G.Y. (1986) Summary of Session 5: Recruitment enhancement. Can. J . Fish. Aquat. Sci., 43, 2384-8. Cruz, R., Baisre, J., Diaz, E., Brito, R., Garcia, C., Blanco, W. & Carrodegas, C. (1987) Atlas Bioldgico-pesquero de la Langosta del Archipidago Cubano. Centro de Investigaciones Pesqueras, La Habana, Cuba, 125 pp. Cruz, R., Brito, R., Diaz, E. & Lalana, R. (1986) Ecologia de la langosta (Panulirus argus) al SE de la Isla de la Juventud. I. Colonization de arrecifes artificiales. Rev. Znv. Mar. (Cuba), 7 , 3-17. Davis, G.E. (1985) Artificial structures to mitigate marina construction impacts on spiny lobster, Panulirus argus. Bull. Mar. Sci., 37, 1514. DItri, F. (1985) Artificial Reefs: Marine and Freshwater Applications. Lewis Publishers, Chelsea, MI, USA. Eggleston, D.B. (1991) Stock enhancement of Caribbean spiny lobster, Panulirus argus (Latreille), using artificial shelters: patterns of survival and dynamics of shelter selection. Ph.D. dissertation, The College of William and Mary, Williamsburg, VA, USA, 143 pp. Eggleston, D.B. & Lipcius, R.N. (1992) Shelter selection by spiny lobster under variable predation risk, social conditions and shelter size. Ecology, 73: 992-101 1. Eggleston, D.B., Grover, J.J. & Lipcius, R.N. (1998) Ontogenetic diet shifts in Nassau grouper: trophic linkages and predatory impact. Bull. Mar. Sci., 63, I1 1-26. Eggleston, D.B., Lipcius, R.N. & Grover, J.J. (1997) Predator and shelter size effects on coral reef fish and spiny lobster prey. Mar. Ecol. Prog. Ser., 149, 43-59. Eggleston, D.B., Lipcius, R.N. & Miller, D.L. (1992) Artificial shelters and survival of juvenile Caribbean spiny lobster Panulirus argus: spatial, habitat, and lobster size effects. Fish. Bull. U.S., 90, 671-702. Eggleston, D.B., Lipcius, R.N., Miller, D.L. & Coba-Cetina, L. (1990) Shelter scaling regulates survival of Caribbean spiny lobster, Panulirus argus. Mar. Ecol. Prog. Ser., 62, 70-88. Elner, R.W. & Campbell, A. (1991) Spatial and temporal patterns in recruitment for American lobster, Homarus americanus, in the Northwestern Atlantic. Mem. Qld Mus., 31, 349-63.

444 Spiny Lobsters: Fisheries and Culture Ennis, J.P. & Fogarty, M.J. (1997) Recruitment overfishing reference point for the American lobster, Homarus americanus. Mar. Freshwat. Res., 48, 1029-34. Evans, C.R., Evans, A.J. & Lockwood, A.P.M. (1995) Scaled-down shelters (casitas) with predatorbarriers having potential for spiny lobster Panulirus argus nursery habitat enhancement. Rev. Cubana Invest. Pesq., 19(2), 3240. Fogarty, M.J. & Idoine, J.S. (1986) Recruitment dynamics in an American lobster (Homarus americanus) population. Can. J. Fish. Aquat. Sci., 43, 2368-76. Fogarty, M.J., Sissenwine, M.P. & Cohen, E.B. (1991) Recruitment variability and the dynamics of exploited marine populations. Trends Ecol. Evol., 6, 241-6. Forcucci, D., Butler, M.J. & Hunt, J.H. (1994) Population dynamics of juvenile Caribbean spiny lobster, Panulirus argus, in Florida Bay, Florida. Bull. Mar. Sci., 54, 805-18. Gonzalez, G., Herrera, A., Diaz, E., Brito, R., Gotera, G., Arrinda, C. & Ibarzabal, D. (1991) Bioecologia y conducta de la langosta (Panulirus argus, Lat.) en las zonas profundas del borde de la plataforma en la region suroccidental de Cuba. Rev. Invest. Mar., 12, 140-53. Gracia, A. (1991) Spawning stock-recruitment relationships of white shrimp in the southwestern Gulf of Mexico. Trans. Am. Fish. Soc., 120, 519-27. Gutierrez, D., Simonin, J. & Briones-Fourzin, P. (1992) A simple collector for postlarvae of the spiny lobster Panulirus argus. Proc. Gulf Carib. Fish. Inst., 41, 516-27. Herrnkind, W.F., Vanderwalker, J. & Barr, L. (1975) Population dynamics, ecology, and behavior of spiny lobster, Panulirus argus, of St. John, U.S. Virgin Islands: habitation and pattern of movements. Nat. Hist. Mus. Los Angeles Cty. Sci. Bull., 20, 3145. Kanciruk, P. (1980) Ecology of juvenile and adult Palinuridae (spiny lobsters). In The Biology and Management of Lobsters, Vol. 2, Ecology and Management (Ed. by J.S. Cobb & B.F. Phillips), pp. 59-96. Academic Press, New York, USA. Lewin, R. (1986) Supply-side ecology. Science, 234, 25-7. Lindberg, W.J (1997) Can science resolve the attraction-production issue? Fisheries, 22, 1C-13. Lipcius, R.N. & Herrnkind, W.F. (1982) Molt cycle alterations in behavior, feeding, and die1 rhythms of a decapod crustacean, the spiny lobster Panulirus argus. Mar. Biol., 68, 241-52. Lozano-Alvarez, E. (1991) Consideraciones sobre el manejo de la langosta Panulirus argus en Bahia de la Ascensibn, Quintana Roo. In Taller Regional sobre Manejo de la Pesqueria de la Langosta (Ed. by P. Briones-Fourzan). Inst. Cienr. del M a r y Limnol. Univ. Nal. Autdn. MPxico. Publ. Tern., 1, 3341. Lozano-Alvarez, E. (1992) Pesqueria, dinamica poblacional y manejo de la langosta Panulirus argus (Latreille, 1804) en la Bahia de la Ascension, Q.R., Mexico. Tesis doctoral, Fac. Ciencias, Univ. Nal. Auton. Mexico, 142 pp. Lozano-Alvarez, E. (1994) Analisis del estado de la pesqueria de la langosta Panulirus argus en el Caribe mexicano. In Recursos Faunisticos Litorales de la Peninsula de Yucatrin (Ed. by A. Yaiiez-Arancibia). EPOMEX-Univ. Autbn. Campeche, Mexico, Sene Cientifica, 2, 42-54. Lozano-Alvarez, E. (1995) Requisitos para la introduccion de refugios artificiales en pesquerias de langostas. Rev. Cubana Invest. Pesq., 19(2), 21-6. Lozano-Alvarez, E. & Briones-Fourzan, P. (1996) Fluctuations in population parameters of the spiny lobster Panulirus argus in a fishery based on artificial shelters. In Proceedings of the Second World Fisheries Congress, Brisbane. Australia, 28 July-2 August, 1996 (Ed. by D.A. Hancock & J.P. Beumer), Vol. 1, 24 (abstract). Lozano-Alvarez, E. & Spanier, E. (1997) Behaviour and growth of captive spiny lobsters (Panulirus argus) under the risk of predation. Mar. Freshwat. Res., 48, 707-13. Lozano-Alvarez, E., Briones-Fourzan, P. & Negrete-Soto, F. (1993) Occurrence and seasonal variations of spiny lobsters, Panulirus argus (Latreille), on the shelf outside Bahia de la Ascension, Mexico. Fish. Bull. US.,91, 808-15.

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Lozano-Alvarez, E., Briones-Fourzan, P. & Negrete-Soto, F. (1994) An evaluation of concrete block structures as shelter for juvenile Caribbean spiny lobsters, Panulirus argus. Bull. Mar. Sci., 54, 351-62. Lozano-Alvarez, E., Briones-Fourzan, P., Negrete-Soto, F. & Barradas-Ortiz, C. (1998) Atributos de la poblacibn de langostas Panulirus argus en la laguna arrecifal de Puerto Morelos, antes y despues de la introduccibn de casitas. In Funcionamiento de refugios artijiciales para langosta y su impact0 en hribitats de pastizal marino (Ed. by P. Briones-Fourzan), pp. 178-212. Informe Final, UNAM-CONACYT, 1 171-N, Mexico. Lozano-Alvarez, E., Briones-Fourzln, P. & Phillips, B.F. (1989) The spiny lobster fishery in Bahia de la Ascension, Q.R., Mexico. In Proc. Workshop Australia-Mexico on Marine Sciences, Mirida, MPxico, July 6-17, 1987 (Ed. by E. Chlvez), pp. 379-91. Centro Inv. Est. AvanzadosInst. Politec. Nal. Mexico. Lozano-Alvarez, E., Briones-Fourzan, P. & Phillips, B.F. (1991) Fisheries characteristics, growth, and movements of the spiny lobster Panulirus argus in Bahia de la Ascension, Mexico. Fish. BUN. U.S., 89, 79-89. Lyons, W.G., Barber, D.G., Foster, S.M., Kennedy, F.S., Jr & Milano, G.R. (1981) The spiny lobster, Panulirus argus, in the middle and upper Florida Keys: population structure, seasonal dynamics and reproduction. Flu. Mar. Res. Publ., 38, 38 pp. Miller, D.L. (1982) Construction of shallow water habitat to increase lobster production in Mexico. Proc. Gulf Carib. Fish. Inst., 34, 168-79. Okechi, J.K. & Polovina, J.J. (1995) An evaluation of artificial shelters in the artisanal spiny lobster fishery in Gazi Bay, Kenya. S. Afr. J. Mar. Sci., 16, 373-6. Olmsted, I. & Ercilla, M.J. (1988) Historia natural de las palmas ‘chit’ y ‘nacax’ en Quintana Roo. Asociacidn de Amigos de Sian kahn, Serie Cuadernos de Sian kahn, No. 2, 28 pp. Penn, J.W., Hall, N.G. & Caputi, N. (1989) Resource assessment and management perspectives of the Penaeid prawn fisheries of Western Australia. In Marine Invertebrate Fisheries: Their Assessment and Management (Ed. by J.F. Caddy), pp. 11540. Wiley Interscience, New York, USA. Phillips, B.F. (1986) Prediction of commercial catches of the western rock lobster Panulirus cygnus. Can. J. Fish. Aquat. Sci.,43, 2126-30. Phillips, B.F., Pearce, A.F. & Litchfield, R.T. (1991) The Leeuwin current and larval recruitment to the rock (spiny) lobster fishery off Western Australia. J . R. SOC.West. Australia, 74, 93-100. Pickering, H. & Whitmarsh, D. (1997) Artificial reefs and fisheries exploitation: a review of the ‘attraction versus production’ debate, the influence of design and its significance for policy. Fish. Res., 31, 39-59. Pitcher, T.J. & Hart, P.J.B. (1982) Fisheries Ecology. Chapman and Hall, New York, USA. Ramos-Aguilar, M.E. (1992) Busqueda de aliment0 y regreso a1 refugio de la langosta Panulirus argus en Bahia de la Ascension, Q.R., MBxico. Tesis profesional, Fac. Ciencias, Univ. Nal. Auton. Mexico, 64 pp. Ratchford, S.G. (1999) The influence of chemical communication on shelter selection, shelter sharing, and aggregation among spiny lobsters, Panulirus argus. Ph.D. dissertation, North Carolina State University, Raleigh, NC, USA, 82 pp. Ratchford, S.G. & Eggleston, D.B. (1998) Size- and scale-dependent chemical attraction contributes to an ontogenetic shift in sociality. Anim. Behav., 56, 1027-34. Rios-Lara, G.V., Zetina-Miguel, C.E. & Cervera-Cervera, K. (1995) Evaluacion de ‘casitas’ o refugios artificiales introducidos en la costa oriente del estado de Yucatan para la captura de langostas. Rev. Cubana Invest. Pesq., 19(2), 5 M 2 . Rotschild, B.J. (1986) Dynamics qf Marine Fish Populations. Harvard University Press, Cambridge, MA, USA. Seaman, W.J., Jr (1997) What if everyone thought about reefs? Fisheries, 22, &5.

446 Spiny Lobsters: Fisheries and Culture Seaman, W.J., Jr & Sprague, L.M. (1991) Artificial Habitatsfor Marine and Freshwater Fisheries. Academic Press, New York, USA. Seijo, J.C., Salas, S., Arceo, P. & Fuentes, D. (1991) Anilisis bioeconbmico cornparativo de la pesqueria de langosta Panulirus argus en la plataforma continental de Yucatan. F A 0 Fish. Rep., 431 (SUPPI.),39-58. Sosa-Cordero, E., Arce, A.M., Aguilar-Davila, W. & Ramirez-Gonzalez, A. (1998) Artificial shelters for spiny lobster Panulirus argus (Latreille): an evaluation of occupancy in different benthic habitats. J . Exp. Mar. Eiol. Ecol., 229, 1-18. Underwood, A.J. & Fairweather, P.G. (1989) Supply-side ecology and benthic marine assemblages. Trends Ecol. Evol.,4, 1619. Warner, R.E., Combs, C.L. & Gregory, D.R., Jr (1977) Biological studies of the spiny lobster, Panulirus argus (Decapoda: Palinuridae) in south Florida. Proc. Gulf Carib. Fish. Inst., 29, 16683.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 24

Recreational Spiny Lobster Fisheries Research and Management R.MELVILLE-SMITH

Bernard Bowen Fisheries Research Institute. Western Australian

Marine Research Laboratories, P.O. Box 20, North Beach, Western Australia 6020, Australia

B.F. PHILLIPS J. PENN

Curtin University. P.O.Box U1987, Perth, Western Australia 6845, Australia

Bernard Bowen Fisheries Research Institute. Western Australian Marine Research

Laboratories, P.O. Box 20, North Beach, Western Australia 6020, Ausrralia

24.1

Introduction

The vast amount of literature dealing with commercial spiny lobster fisheries worldwide, combined with seafood marketing hype, often leads us to forget that it has only been during the twentieth century that these animals have had any real economic value. Historically, spiny lobsters were harvested by the indigenous inhabitants of many parts of the world (e.g. Maori in New Zealand, Leach & Anderson, 1979; the Strandlopers in South Africa, Grindley, 1967; Parkington, 1976; and the Aboriginals in Australia, Gray 1992). In the late nineteenth and early twentieth century, this now highly priced commodity was considered to be food for the poor (van Sittert, 1992). The subsequent increase in catch and effort in the major spiny lobster fisheries since World War I1 and the development of particularly the US markets for the product (Bowen, 1980), have affected the access that recreational fishers have to spiny lobsters in different countries. In some countries lobster fishing is restricted to commercial fishers (e.g. Brazil: Fonteles-Filho, Laboratorio de Ciencias do Mar, Brazil, pers. comm.; Mexico: Vega et al., 1997; Oman: M.S.M. Siddeek, Sultan Qaboos University, Oman, pers. comm.; Japan: J. Kittaka, Research Institute for Marine Biological Science, Hokkaido, Japan, pers. comm.). In other countries recreational fishers are permitted to harvest a limited number of lobsters for their own use (e.g. Australia, New Zealand, USA, South Africa and Namibia) or for cultural ceremonial use (New Zealand). The aim of this chapter has been (1) to review the various management measures that have been adopted by a range of countries that have recreational spiny lobster fisheries; (2) to review the methods that have been used by those countries that have attempted to measure the impact of these non-commercial fishing operators; and (3) to compare the sizes of recreational fisheries with commercial fisheries in those countries where such data exist. The countries and regions which have been compared are by no means the only ones with recreational spiny lobster fisheries, however, they do include those with well-recognized fisheries. The authors 447

448 Spiny Lobsters: Fisheries and Culture

acknowledge that there are probably many other spiny lobster recreational fisheries, however, most of these are either very small, or in other cases, available data have not distinguished between catches made by commercial, subsistence and recreational fishers. It has been of interest to note the large quantity of unpublished or ‘grey’ literature dealing with recreational spiny lobster fisheries in various parts of the world. Much of this literature has dealt with spiny lobster recreational fishery assessments covering limited spatial and or temporal boundaries, with the result that these may often be considered as lower limits of a greater likely total catch. These incomplete assessments, often with wide confidence limits around estimated population parameters, have made their publication in the formal literature difficult. In this chapter, these data have been synthesized into a published form, thereby making them accessible to the scientific community.

24.2

Management regulations in recreational lobster fisheries

Unlike commercial fisheries, there is very little uniformity in the way that recreational spiny lobster fisheries are managed internationally. Even within countries there are frequently substantial regional differences in the way in which this sector is controlled. In those countries where recreational fishing is allowed, authorities generally have size, bag limits, seasonal and gear restrictions in place, but frequently do not require fishers to have a licence to fish for lobsters (Table 24.1). There is an understandable reluctance on the part of politicians to force recreational fishers to purchase licences for this pastime. Some argue that any marine resource is a common property and that it is the democratic right of a citizen to harvest lobsters, or any other fish for that matter, for personal consumption. However, this review shows that with few exceptions, reliable information on fishing activity or catches made by the recreational sector is only available in those countries in which rock lobster licences are sold (Table 24.1). Unlike commercial spiny lobster fisheries, landings made by the recreational component are difficult to regulate, and where these fisheries occur they are generally managed by a combination of input and output controls. Most areas covered by this review were shown to have well-defined spiny lobster fishing seasons and, with few exceptions, these were similar to the commercial fishing seasons (Table 24.1). In recent years, South African authorities have attempted to restrict recreational lobster fishers to only fish weekends and public holidays. However, attempts to legislate such changes for the 1997/98 season were thwarted by court actions that were brought about by recreational fishers (Cockcroft et al., 1999). Most spiny lobster fisheries are regulated by a legal minimum size, although there are exceptions such as in parts of Australia (Queensland and Northern Territory). In most countries with both recreational and commercial spiny lobster fisheries, the minimum size has tended to be the same for both sectors; however, in South Africa

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449

commercial fishers have a legal minimum size which is 5 mm smaller than the size for recreational fishers (Table 24.1). This smaller minimum size for commercial fishers was introduced in the early 1990s for economic reasons (Cockcroft & Payne, 1999). Most recreational fisheries allow passive fishing methods such as the use of lobster pots and/or drop nets, as well as active fishing in the form of diving. The Hawaiian recreational fishery was the only one that the authors could find reference to allowing the use of tangle netting by recreational spiny lobster fishers (Table 24.1). The number of traps, pots, hoop or drop nets which recreational fishers are permitted to use per person tends to be quite variable in different countries (Table 24. l), but is generally restricted to between one and four per person. Only in Hawaii and parts of New Zealand are there no restrictions on the amount of this type of gear that may be used per recreational fisher. All countries with recreational spiny lobster fisheries that were surveyed permitted snorkel or free diving for lobsters and a substantial number allowed artificial air supply methods (SCUBA and hookah). All permitted divers to use a gloved hand to catch the lobsters, but less common was the legal use by divers of nooses, crooks and hooks (Fig. 24.1). Queensland, Australia, was the only area covered by Table 24.1 that permitted the use of spears and spear guns by recreational spiny lobster fishers. In addition to having restrictions on the amount of gear that can be used, most recreational fisheries restrict the number of lobsters that can be landed per fisher. Numbers per fisher range from two per person per day (New South Wales, Australia; Table 24.1) to eight per person per day (Western Australia, Australia; Table 24. l),

Fig. 24.1 A noose and crook used for catching lobsters in a number of recreational lobster fisheries. That part of the equipment used for actively capturing the animal is shown in detail in the insert of the main photograph.

450 Spiny Lobsters: Fisheries and Culture Table 24.1 Comparative summary, for selected countries, of some kev recreational and commercial rock lobster legislation and exploitation statistics Ao.b.lMb

-

Firhins ~ ~ ~ w r c l d ~ m*,mm 11mI-ml)

nnmui~~or.iiim" lhlnmCL I Flblulum"

ImmmcLmkmm' Y(.J mm CL mmkn m d '

mrnc,, . N b . . h l " h " glwdh.nd.nrmr.r&?'

.Ilea., 1 8 $ ~ l S 9 1 N 6 ' ~ rars.,lmm I&*. wu"B na p""yd'~ 1 t I C U t 181m91M)"'

Recreational Spiny Lobster Fisheries

45 1

Table 24.1 continued.

Reference list I. Food and Agriculture Organization (1999) Fishstat Plus (v.2.19). CD-ROM. FAO, Rome. 2. R. Bertelsen, pers. comm., Florida Department of Environmental Protection, Florida, USA. 3. Chapter I. 4. Chakalall, B. (1995) Fisheries management in the lesser Antilles. In South Purific Commission and Forum Fisheries Agency Workshop on the Management of South Pacific Inshore Fisheries. Volume 11. (Ed. by P. Dalzell and T.J.H. Adams), pp. 185-219. Noumea, New Caledonia. 5. Montgomery, S., Chen, Y., Craig, J. & Diver. L. (1998) An assessment of the NSW eastern rock lobster resource for 1998199. Fish. Res. Assess. Ser., 4, 65 pp. 6. Bradford, E. (1999) Harvest of major recreational species: comparison of results from the regional and national diary surveys. NIWA Tech. Rep., 60, 20 pp. 7. Prescott, J. (cited in Tyrer, B.) (1994) A discussion paper on management options for the South Australian recreational rock lobster fishery. S. Aust. Fish. Manage. Ser., 2, 20 pp. 8. Cockcroft. A.C. & Mackenzie, A.J. (1997) The recreational fishery for west coast rock lobster Jusus lulandii in South Africa. S. Afr. J . Mar. Sci., 18, 75-84. 9. Cockcroft, A.C. & Payne, ALL. (1999) A cautious fisheries management policy in South Africa: the fisheries for rock lobster. Mar. Poliry. 23(6), 587400. 10. Tomalin B.J. & Tomalin, M. (1997) Estimated landings of coastal invertebrates by recreational collectors in Kwazulu-Natal, 1963-1995. Part 1: Annual totals. ORI Data Rep., 96.2. Oceanographic Research Institute, Durban, South Africa.

452 Spiny Lobsters: Fisheries and Culture 11. Tomalin B.J. (1995) Invertebrates harvested in Kwazulu Natal: their ecology, fishery and management. Oceanogr.

Res. Insf. Booklet No. I, 22 pp. Oceanographic Research Institute, Durban, South Africa. 12. B. Tomalin, pers. comm., Oceanographic Research Institute, Durban, South Africa. 13. Anon. (1997) Recreational Rock Lobsler Fishing 1998. Tasmania Department of Primary Industry and Fisheries,Tasmania, Australia. 14. Sharp, W.C., Bertelsen, R.D. & Hunt, J.H. (in press). The 1994 Florida recreational spiny lobster fishing season: results of a fisher mail survey. Proc. Gulf Carib. Fish. 15. Henry, F. & Hanan, D. (1997) Review of some California fishieries for 1996. Fisheries Review: 1996. CalCOFI Rep., 38, 7z21. 16. G. Liggins, pers. comm.. New South Wales Fisheries Research Centre, Cronulla, New South Wales, Australia. 17. B. Luckhurst, pers. comm., Division of Fisheries, Bermuda. 18. Anon. (1997) , Australia. Marine Recreational Fishing in New South Wales - A BriefGuide to Rules. NSW Fisheries, New South Wales. 19. Anon. (1998) Recreational Fishing Information Brochure. Sea Fisheries, South Africa. 20. J. Prescott, pers. comm.. South Australian Research and Development Institute, Adelaide, Australia. 21. Annala, J.H. & Sullivan, K.J. (comps.). (1998) Report from the mid-year Fishery Assessment Plenary, November 1998: stock assessments and yield estimates, 44 pp. Unpubl. Ministry of Fisheries Rep. 22. Anon. (1998) Vicorian Recreational Fishing Regulations Guide 1998-99,46 pp. Outdoor Empire Publishing, Victoria, Australia. 23. Lyle, J.M. & Smith, J.T. (1998) Pilot survey of licensed recreational sea fishing in Tasmania - 1995/96. Tech. Rep., 51, 55 pp. Department of Primary Industry and Fisheries Tasmania, Marine Research Laboratories, Taroona, Tasmania, Australia. 24. J. M. Lyle & C. Gardner, pers. comm., Tasmanian Aquaculture and Fisheries Institute, Hobart, Tasmania, Australia. 25. Anon. (1998) Fishing.for Rock Lobsters: Fish f o r the Future 1998/99 Season. Fisheries Western Australia, Australia. 26. Melville-Smith, R. & Anderton, S.M. (2000) Western rock lobster mail surveys of licensed recreational fishers 1986/ 87-1998/99. Fish. Res. Rep., 122, Fisheries Western Australia, Australia. 27. Teirney, L.D., Kilner, A.R.. Millar, R.B., Bradford, E. & Bell, J.D. (1997) Estimation of recreational harvests from 1991-92 to 1993-94. N . Z . Fish. Assess. Res. Doc. 97/15, July 1997, 43 pp. 28. Anon. (1999) South Australian Recreational Fishing Guide. Primary Industries and Resources SA, South Australia, Australia, 61 pp. 29. A. Cockcroft, pers. comm., Marine &Coastal Management, Department of Environment Affairs and Tourism, Cape Town, South Africa. 30. Hobday, D.K., Ryan, T.J., Thomson, D.R. & Treble, R.J. (1998) Assessment of the Victorian rock lobster fishery. Fish. Res. Dev. Co.final report, 921104, 177 pp. 31. C. Gardner, pers comm., TAFI, Marine Research Labs., Taroona, Tasmania, Australia. 32. S. Montgomery, pers comm., New South Wales Fisheries Research Institute, Cronulla, New South Wales, Australia. 33. Andrew, N.L., Reid, D.D. & Murphy, J.J. (1997) Estimates of the 1997 recreational abalone harvest in N.S.W. N . S . W . Fisheries infernal report, 13 pp. 34. W. Sumpton, pers. comm., Southern Fisheries Centre, Department of Primary Industries, Deception Bay, Queensland, Australia. 35. Anon. (1995) Fisheries Regulation 1995. Government Printer, Queensland, Australia. 36. R. Clarke. pers. comm., Northern Territory Department of Primary Industry and Fisheries, Darwin, Northern Territory, Australia. 37. J. Polovina, pers. comm.. National Marine Fisheries Service, Honolulu Laboratory, Hawaii, USA. 38. Erhardt, N.M., Legault, C.M. & Pike, C.S. (1991) An evaluation of the impact of fishing practices on the spiny lobster, Panulirus argus, fishery in South Florida. In Proc. 44th GulfCarib. Fkh. Inst. (Ed. by M.H. Goodwin & G.T. Waugh), pp. 75-102. Nassau, Bahamas. 39. Ward, J.A. & Luckhurst, B.E. (1991) Development of a lobster-specific trap in Bermuda and fisheries management considerations for the re-establishment of a commercial lobster fishery. In Proc. 44fh Gu/f Carib. Fish. (Ed. by M.H. Goodwin & G.T. Waugh), pp. 566-78. Nassau, Bahamas. 40. Muller, R.G., Hunt, J.H., Matthews, T.R. & Sharp, W.C. (1997) Evaluation of effort reduction in the Florida Keys spiny lobster, Panulirus argus, fishery using an age-structured population analysis. Mar. Freshwat. Res., 48, 1045-58. 41. Department of Environment Affairs and Tourism. Cape Town, South Africa, unpubl. data. 42. C.A.F. Grobler, pers. comm., Ministry of Fisheries and Marine Resources, Luderitz, Namibia. 43. D. Eggleston, pers. comm.. Department of Marine Earth and Atmospheric Sciences, North Carolina State University, NC, USA. 44. DSykes, pers. comm., New Zealand Rock Lobster Industry Council, Wellington, New Zealand. 45. D. Schoeman, pers. comm., Department of Sea Fisheries, Cape Town, South Africa. 46. R.B. Read, pers. comm., Department of Fish and Game - Marine Region, San Diego, CA. USA. 47. H.J. Ceccaldi, pers. comm., FacultC des Sciences et Techniques de Saint-Jerome, Marseille, France. 48. C. Turnbull, pers. comm. Northern Fisheries Centre, Department of Primary Industries, Cairns, Queensland, Australia.

Recreational Spiny Lobster Fisheries

453

and over a very limited period to 12 per person per day (Florida, USA; Table 24.1). In all areas where there were diver and trap recreational fisheries, fishers were allowed to retain the same number of lobsters regardless of the fishing methods being used (Table 24.1). There is little published research on the compliance characteristics of recreational and/or commercial lobster fishers. Compliance with fisheries regulations has been shown on parts of the Victorian (Australia) coast to be substantially lower among recreational divers fishing for rock lobster and abalone than among commercial marine and inland fisheries and marine and inland anglers (Smith et al., 1996). In South Africa, inadequate enforcement and illegal fishing have been identified as a major concern for the future of lobster and other inshore fish species (Cockcroft et al., 1999). In Western Australia a study has recently commenced aimed at ascertaining attitudes of recreational and commercial lobster fishers towards compliance, with a view to using this information to improve the monitoring of these two resource user groups (McKinlay, 1999).

24.3

Management strategies for recreational fishing

Recreational spiny lobster fishing is a pastime that is generally enjoyed by reasonably affluent communities usually living in developed countries in North America, Europe and Australasia. Subsistence and traditional fishing generally takes place in African and Indo-Pacific Island areas and, because of a lack of infrastructure in many of these areas, most of this fishing activity goes unreported. The problem of spiny lobster recreational fishers illegally selling their catch is one which has proved difficult for managers to control. To counter these illegal practices, recreational lobster fishers in Western Australia, South Australia and Tasmania (Australia) are required to mark their catch by either clipping or punching the central tail fan (telson) within a limited period of the animals being landed. The purpose of this procedure is to assist enforcement staff checking restaurants and fish sales outlets, to be able to identify lobsters that might have been obtained illegally through recreational instead of commercial fishers (Fig. 24.2). Few spiny lobster fisheries are managed with recreational fishers in mind. Usually, management is focused on sustainability issues in the commercial fisheries, and the recreational sector finds itself to be just another factor in the equation. However, this is likely to change in the future as the proportion of the total catch taken by recreational compared with commercial fishers becomes recognized as being substantial (Table 24.1) and is shown to be growing, as it has in those parts of the world with long-term data sets for the two sectors. Attention has moved in recent times to the economic value of recreational fisheries. No specific economic assessments of spiny lobster recreational fisheries have been published to date, but there is growing acceptance amongst managers that there can be substantial economic benefits to regional economies in promoting

454 Spiny Lobsters: Fisheries and Culture

Fig. 24.2 A lobster with the tail fan cut. A number of recreational lobster fisheries requires fishers to clip or punch the tail fan at, or shortly after capture. This legislation is used to enable recreationally caught lobsters to be identified if any attempt is made to sell them commercially.

general recreational fishing activities (Riechers et al., 1991; Lindner & McLeod, 1991). One of the more controversial aspects relating to recreational fishing activities which probably still needs to go some way towards being properly resolved in cost recovered fisheries, is the question of this groups responsibility towards the costs of managing and policing its own sector. A number of spiny lobster recreational fisheries requires participants to purchase a licence each season, and this could potentially offset in part the provision of management services.

24.4

Estimating recreational catch and effort

There is a vast amount of literature dealing with the estimation of catch and effort by recreational fishers, most of it directed at inland freshwater rather than marine

Recreational Spiny Lobster Fisheries

455

fisheries. The relatively widespread acceptance by administrators and fishers of the need for licences to fish in inland waters has made the task of assessing these fisheries more manageable than in the marine situation. It is no coincidence that those areas which have long-term spiny lobster recreational fisher data sets (Table 24.1) are also those with the longest history of having had a spiny lobster recreational licensing system in place. Many different survey methods are available to provide information on recreational fisher catches, and these often differ with respect to their underlying assumptions, biases and possible imprecision. Improper sample selection, noncoverage, recall bias, intentional misreporting and numerous other survey considerations have been detailed by, among others, Essig & Holliday (1991) and Cowx (1991). It is essential to have clear objectives in mind when deciding on which survey method is most appropriate. Since cost is frequently a limiting factor in deciding on an appropriate method and since spiny lobster recreational fishing areas are usually geographically widespread with many access points, most recreational fisher catch estimates to date have used mail and telephone survey assessment methods (Table 24.1). Recreational lobster fisheries have long been suggested as having a significant impact on the total catch, but estimates of the size of this catch have often been based on little more than opinion (e.g. the estimate by Frey, 1971, of the Californian recreational spiny lobster catch possibly being 50% of the commercial catch at that time). Such ‘opinion’ data can be useful if treated appropriately, as has been shown by Zuboy (1981) in his early estimation of the recreational diver catch of spiny lobsters in Florida waters using the delphi technique to develop a consensus of expert opinion. Where on-site (roving creel and access point) surveys of spiny lobster recreational fishers have been undertaken, their scope has generally been limited to a relatively small well-defined area over a limited period during the fishing season (e.g. Bergh & Barkai, 1991, in south-western South Africa; Harris et al., 1993, in southern California; Burke Marketing Research Inc., 1995, in southern California; Teirney, 1994, in southern New Zealand). Large-scale use of these methods has generally been found to be logistically complex and expensive, which is why, with the exception of Norton (198 l), all other spiny lobster-specific recreational fishing creel surveys that have interviewed fishers on the ground have been limited in their scope and outcome. Off-site methods of surveying spiny lobster recreational fishers have been much more widespread. Some studies (Harris et al., 1993; Hobday et al., 1998) have made use of the fact that many recreational spiny lobster fishers use diving shops to fill their diving cylinders, and charter boats to transport them to diving sites. They have used these collection points, together with information accessed through diving clubs, as a primary source of recreational lobster catch and effort information. In recreational spiny lobster fisheries for which licences are required to participate, researchers have been able to use random mail and telephone surveys to target permit holders. Varying degrees of success in quantifying catches in particular

456 Spiny Lobsters: Fisheries and Culture lobster fisheries have been achieved using mail surveys (Prescott, unpubl. data, cited by Tyrer, 1994; Tomalin & Tomalin, 1997; Melville-Smith & Caputi, 1996) as well as by telephone surveys (Cockcroft & Mackenzie, 1997). More common than the lobster-specific mail and telephone surveys of recreational fishers have been telephone surveys where spiny lobsters have been only one of a number of species being surveyed (e.g. Anon., 1989; Coleman, 1998; Andrew et al., 1997). In recent times, several states and countries have moved towards adopting the telephone survey/diary approach to quantify catches made by recreational fishers (e.g. New Zealand: Teirney et al. 1997; Bradford, 1998; Tasmania, Australia: Lyle & Smith, 1998; South Australia: MacGlennon, pers. comm.). This method involves the survey organizers randomly selecting households in a particular survey area and questioning those people on their fishing activities. Results from this type of survey provide information on the numbers of people per household that are involved in recreational fishing. All households that fish are asked to assist in a recreational fisher logbook programme which requires the participating householder to record accurately his or her catch on each fishing expedition over a given period. The benefit of this method is that it combines the flexibility of an offsite (telephone) survey method with the accuracy of an onsite (in this case a pseudo-access point) assessment method. Telephone and mail surveys, while they are relatively inexpensive to run, have a downside in that they generally require the participant to recall his or her fishing activity over an extended period. Numerous studies have shown that this can lead to biases associated with recall memory, angling prestige or exaggeration and enthusiasm (Brown, 1991; Cowx, 1991; Essig & Holliday, 1991). Telephone/diary surveys of the kind mentioned in the previous paragraph combine the positive aspects of telephone surveys while allowing the project manager to encourage the survey participants to keep good diary records. This dual approach to recreational fisher record keeping is considered to reduce the biases associated with many other recreational fishing survey techniques. An aspect of recreational spiny lobster fishing effort which has yet to be fully considered by workers in this research area is the effect that improvements in gear technology may have had on the fishing power of this sector. GPS, colour echo sounders, power winches, dive computers and underwater torches have become increasingly common items of equipment used by recreational lobster fishers, and surveys need to capture the increase in use of these fishing aids so that increases in effective fishing effort in this sector may be tracked over time. In Western Australia, mail surveys of recreational lobster licence holders for the 1998/99 season have specifically included questions about boat size and electronic navigational and fishing aids (Melville-Smith & Anderton, 2000).

Recreational Spiny Lobster Fisheries 24.5

457

The future of non-commercial spiny lobster fishing

Discussions regarding management policy have, in the past, been dominated by commercial fishing groups; however, this is rapidly changing in Australasia where the interests of recreational and environmental groups are increasingly being taken into account in decision-making processes. Human dimension (HD) studies, which examine peoples actions and motivations regarding fishery resources (Aas & Ditton, 1998) have become common, particularly in freshwater fisheries management (Brown, 1987; Ditton, 1996; Baker & Pierce, 1997; Aas & Ditton, 1998). There is a need for similar studies of spiny lobster resources in order to assist managers to establish appropriate balances between the different user and non-user groups in the future. One component of any H D study would compare the economic importance of recreational with commercial exploitation of lobsters. We are not aware of any such study of a spiny lobster fishery, despite the fact that several important spiny lobster producer countries have large recreational fisheries (Table 24.1). Furthermore, many of these producer areas have experienced substantial increases over time in the proportion of the total catch that is being taken by the recreational sector. Cockcroft & Mackenzie (1997), for example, have documented an increase in the number of recreational west coast rock lobster licences sold in South Africa from -28 000 in the early 1980s to -58 000 in the 1995/96 season. Norton (1981) showed the recreational catch in Western Australia in the late 1970s to be 1.6% of commercial spiny lobster catch, but in the late 1990s these catches were estimated to be in the order of 4 5 % (Melville-Smith & Anderton, 2000), or an increase in the overall recreational catch share of 300%. In many cases, simple comparisons of recreational and commercial catches underrepresents the impact that recreational catch share can have on localized fishing grounds. Most recreational catches tend to be made close to metropolitan areas and in inshore waters. Lyle & Smith (1998), for example, have shown that the effect of recreational fishing is only really on the shallow-water east coast of Tasmania. Although the overall recreational catch is only 5% of the commercial catch, the fact that most of the catch made by this sector is taken in shallow water (<20 m) on the east coast means that the proportion of the combined recreational and commercial lobster catch taken by the recreational sector in the shallow water on the east coast of Tasmania is likely to be around 40% of the commercial catch. Similarly, Hobday et al. (1998) have shown that while recreational fishers only harvest an estimated 3.9% of the total commercial catch in Victoria, Australia, their share from depths <20 m may be 20.8%. Their catch share of the Eastern Zone catch, which incorporates Melbourne and surrounding areas, for depths <20 m could be as high as 46.3% of the landed commercial catch. Recreational lobster catches in the Perth region of Western Australia are particularly localized and in some years landings made by that sector are similar to those made by the commercial fishery in depths of less than 10 fathoms (22 m) (Melville-Smith & Anderton, 2000).

458 Spiny Lobsters: Fisheries and Culture Increases in recreational fishing catch at the expense of commercial lobster fishing catch will undoubtedly create increasing conflict in the future between these two user groups. Concerns relating to this likelihood have formed the basis of certain survey studies and discussion articles, for example, in the southern Australian States (Smith et al. 1996), Western Australia (Chubb & Melville-Smith, 1996), South Africa (Bergh & Barkai, 1991), Florida (Beardsley el al., 1975) and New Zealand, (Sykes, 1999). Some recent changes to circumstances and legislation in different parts of the world may provide some pointers as to the likely future of recreational spiny lobster fishing. As has been shown, there are very obvious differences internationally in the way that various countries manage their recreational lobster fisheries, with some opting to preclude this sector altogether, while others, mostly in Australasia, America and southern Africa, encourage the recreational and commercial sectors to coexist. Based on recent trends it would seem that in the case of Australasia there may not be the political will to control growth of recreational fishing relative to the commercial sector. In terms of the commercial sector, a best-case scenario might see certain areas allocated to the recreational sector in return for exclusive fishing rights for commercial fishers in other areas. From a commercial fishing point of view, a worst-case scenario might see that sector being bought out by government on behalf of recreational fishers. In a recent case in Western Australia, for example, a commercial lobster fisher in the Dampier Archipelago was bought out so as to provide exclusive rights to the tropical lobster resource in that area to recreational lobster divers (Anon., 1997, 1998). In South Africa, it would seem that a reverse trend is taking place and that commercial fishers, particularly new entrants, may ultimately benefit at the expense of the recreational lobster fishing sector. The fishery for Panulirus homarus rubellus on the South African East coast has to all intents and purposes been unexploited by commercial fishers, while on the West Coast recreational lobster fishers have at times harvested up to 29.5% of the annual commercial Jasus lalandii catch during the 6.5month (at the time) recreational fishing season (Cockcroft & Payne, 1999). Since the 1997/98 season, a new semicommercial sector known as subsistence fishers has been recognized and licensed (Cockcroft et al., 1999). These fishers, of which 928 currently exist (Cockcroft et al., 1999), are permitted to harvest four lobsters per day for sale to the public. Since the introduction of this new sector, recreational lobster fishers have had their season shortened by a month and a moratorium was placed on recreational permit sales in the 1997/98 season in order to accommodate the new participants without exceeding the total allowable catch allocated to the fishery (Cockcroft et al., 1999). Proposals are currently being considered which may see a limited number of commercial fishers allowed to harvest lobsters on the South African east coast (B. Tomalin, Oceanographic Research Institute, Durban, South Africa pers. comm.). Since that area is currently restricted only to recreational fishing for lobsters, any introduction of commercial fishing would have to be at the expense of the non-commercial sector.

Recreational Spiny Lobster Fisheries

459

This review indicates that recreational commercial fishing for spiny lobsters is an increasingly common factor to be taken into account in managing these very valuable stocks. While a variety of political and management solutions has been adopted to deal with the complex issue of resource sharing, the major challenge facing resource managers in the future is to ensure that the combined catch remains within sustainable limits. The corresponding challenge for fisheries researchers is to develop reliable and accurate methods to monitor recreational catches for input to the stock assessment process needed to underpin management.

References Aas, 0. & Ditton, R.B. (1998) Human dimensions perspective on recreational fisheries management: implications for Europe. In Recreational Fisheries Social, Economic and Management Options (Ed. by P. Hickley & H. Tompkins), pp. 153-64. Fishing News Books, Blackwell Scientific Publications, Oxford, UK. Andrew, N.L., Reid, D.D. & Murphy, J.J. (1997) Estimates of the 1997 recreational abalone harvest in N.S.W. N.S.W. Fisheries Internal Report, 13 pp. Anon. (1989) Recreational fishing Western Australia July 1987. Australian Bureau of Statistics, Catalogue No. 7602.5, 64 pp. Anon. (1997) Changes for Dampier Archipelago. Western Fisheries, Spring 1997, p. 6. Anon. (1998) Govt payout settles Dampier dispute. ProWest Jan/Feb. 1998, p. 6. Baker, D.L. & Pierce, B.E. (1997) Does fisheries management reflect societal values? Contingent valuation evidence for the River Murray. Fish. Manage. Ecol., 4, 1-15. Beardsley, G.L., Costello, T.J., Davis, G.E., Jones, A.C. & Simmons, D.C. (1975) The Florida spiny lobster fishery. Florida Sci., 39(3), 144-9. Bergh, M.O. & Barkai, A. (1991) The impact of publicly operated small craft on the West Coast rock lobster resource. Unpub. Final Report for the South African West Coast Rock Lobster Industry, 36 pp. Bowen, B.K. (1980) Spiny lobster fisheries management. In The Biology and Management of Lobsters, Vol. I1 (Ed. by J.S. Cobb & B.F. Phillips), pp. 243-64. Academic Press, New York, USA. Bradford, E. (1998) Harvest estimates from the 1996 national marine recreational fishing surveys. New Zealand Fisheries Assessment Research Document 98/16, 27 pp. Brown, T.L. (1987) Typology of human dimensions information needed for Great Lakes sportfisheries management. Trans. Am. Fish. SOC.,116, 3 2 M . Brown, T.L. (1991) Use and abuse of mail surveys in fisheries management. In Creel and angler surveys in fisheries management (Ed. by D. Guthrie, J.M. Hoenig, M. Holliday, C.M. Jones, M.J. Mills, S.A. Moberly, K.H. Pollock & D.R. Talhelm), pp. 255-61. American Fisheries Society Symposium 12. Burke Marketing Research, Inc. (1995) Southern California Lobster Survey. Unpubl. Research Report conducted for California Seafood Council, 7 pp. Chubb, C.F. & Melville-Smith, R. (1996) Recreational rock lobster fishing . . . a community dilemma. Western Fisheries, Autumn 1996, pp. 26-9. Cockcroft, A.C. & Mackenzie, A.J. (1997) The recreational fishery for west coast rock lobster Jaws lalandii in South Africa. S. Afr. J. Mar. Sci., 18, 75-84. Cockcroft, A.C. & Payne, A.I.L. (1999) A cautious fisheries management policy in South Africa: the fisheries for rock lobster. Mar. Policy, 23(6), 587-600.

460 Spiny Lobsters: Fisheries and Culture Cockcroft, A.C., Griffiths, M.H. & Tarr, R.J.Q. (1999) Marine recreational fisheries in South Africa: status and challenges. In Evaluating the Benefits of Recreational Fisheries. University of British Columbia Fisheries Centre Research Reports, 7, 64-70. Coleman, A.P.M. (1998) Fishcount: a survey of recreational fishing in the Northern Territory. Northern Territory Government Department of Primary Industry and Fisheries, Fishery Report No. 41, 35 pp. Cowx, I.G. (1991) Catch and effort sampling strategies: conclusions for management. In Catch Eflort Sampling Strategies: Their Application in Freshwater Fisheries Management (Ed. by I.G. Cowx), pp. 4 0 4 1 3. Fishing News Books, Blackwell Scientific Publications, Oxford, UK. Ditton, R.B. (1996) Human dimensions in fisheries. In Natural Resource Management: The Human Dimensions (Ed. by A.W. Ewert), pp. 73-90. Westview Press, Boulder, CO, USA. Essig, R.J. & Holliday, M.C. (1991) Development of a recreational fishing survey: the marine recreational fishery statistics survey case study. In Creel and Angler Surveys in Fisheries Management (Ed. by D. Guthrie, J.M. Hoenig, M. Holliday, C.M. Jones, M.J. Mills, S.A. Moberly, K.H. Pollock & D.R. Talhelm), pp. 245-54. American Fisheries Society Symposium 12, American Fisheries Society. Fisher, M.R. (1996) Estimating the effect of nonresponse bias on angler surveys. Trans. Am. Fish. SOC.,125, 118-26. Frey, H.W. (1971) California’s living marine resources and their utilisation. Gal$ Dept Fish. Game, unnum. publ., 1-148. Gray, H. (1992) The western rock lobster Panulirus cygnus. Book I : A Natural History. Westralian Books, Geraldton, Australia. Grindley, J.R. (1967) The Cape rock lobster Jasus Ialandii from the Bonteberg excavation. S . Afr. Archaeol. Bull., 22, 94102. Harris, S.L., Haaker, P.L. & Taniguchi, I.K. (1993) Results of the 1992 California recreational spiny lobster opener intercept and mail surveys. California Department of Fish and Game, unpubl. internal research report, 8 pp. Hobday, D.K., Ryan, T.J., Thomson, D.R. & Treble, R.J. (1998) Assessment of the Victorian rock lobster fishery. Fisheries Research and Development Corporation final report 92/104, I77 pp. Leach, B.F. & Anderson, A.J. (1979) Prehistoric exploitation of crayfish in New Zealand. In Birds of a Feather: Osteological and Archaeological Papers from the South Pacific in Honour of R.J. Scarlett (Ed. by A. Anderson). Br. Archaeol. Rep., Int. Ser., 62, 141-64. Lindner, R.K. & McLeod, P.B. (1991) The economic impact of recreational fishing in Western Australia. Fisheries Department of Western Australia, Fisheries Management Paper 38, 44 pp. Lyle, J.M. & Smith, J.T. (1998) Pilot survey of licensed recreational sea fishing in Tasmania 1995/96. Department of Primary Industry and Fisheries, Tasmania, Marine Research Laboratories, Taroona, Technical Report 51, 55 pp. McKinlay, J.P. (1999) Achieving Positive Compliance outcomes in the Western Australian Rock Lobster Fishery. Conference proceedings, 26th Australasian Fisheries Law Enforcement Conference, 4-6 May 1999, Bunbury, Western Australia, 26 pp. Melville-Smith, R. & Anderton, S.M. (2000) Western rock lobster mail surveys of licenced recreational fishers 1986/87-1998/99. Fisheries Research Report No. 122, Fisheries Western Australia. Melville-Smith, R. & Caputi, N. (1996) Prizes boost survey results - the 1995-96 recreational rock lobster survey. Western Fisheries, Spring/Summer 1996, 32-3. Norton, P.N. (1981) The amateur fishery for the western rock lobster. Western Australia Department of Fisheries and Wildlife Research Report 46, 108 pp. Parkington, J.E. (1976) Coastal settlement between the mouths of the Berg and Olifants Rivers, Cape Province. S. Afr. Archaeol. Bull., 31, 127-40. Riechers, R.K., Matlock, G.C. & Ditton, R.B. (1991) A dual-survey approach for estimating the economic aspects of fishing. In Creel and Angler Surveys in Fisheries Management (Ed. by

Recreational Spiny Lobster Fisheries

46 1

D. Guthrie, J.M. Hoenig, M. Holliday, C.M. Jones, M.J. Mills, S.A. Moberly, K.H. Pollock & D.R. Talhelm), pp. 344-55. American Fisheries Society Symposium 12, American Fisheries Society. Sittert, L. van (1992) Labour, capital and the state in the St Helena Bay fisheries c. 1 8 5 6 ~ 1956. . Ph.D. thesis, University of Cape Town, South Africa, 420 pp. Smith, J.T., Winstanley, R. & Tyrer, B. (1996) Management of the Southern Rock Lobster (Jasus edwardsii) fishery for recreation in Tasmania, South Australia and Victoria. In Same Fish Different Rules: Proceedings of the National Fisheries Management Network Workshop, Rottnest Island, August 1995 (Ed. by F. Prokop), pp. 19-27. Fisheries Department of Western Australia, Fisheries Management Paper No. 87. Sykes, D. (1999) National Rock Lobster Management Group 1998 annual report and recommendations. Seafood New Zealand, March 1999, 13-16. Teirney, L. (1994) Determining the recreational share of New Zealand’s marine harvest. In Recreational Fishing: What’s the Catch? (Ed. by D.A. Hancock), pp. 3 1 4 . Australian Society for Fish Biology Workshop Proceedings, Canberra, August 3C31, 1994. Teirney, L.D., Kilner, A.R., Millar, R.B., Bradford, E. & Bell, J.D. (1997) Estimation of recreational harvests from 1991-92 to 1993-94. New Zealand Fisheries Assessment Research Document 97/15, 43 pp. Tomalin, B.J. & Tomalin, M. (1997) Estimated landings of coastal invertebrates by recreational collectors in Kwazulu-Natal, 1963-1995. Part 1: Annual totals. Oceanographic Research Institute Data Report 96.2, Durban, South Africa, 28 pp. Tyrer, B. (1994) A discussion paper on management options for the South Australian recreational rock lobster fishery. South Australian Fisheries Management Series Paper No. 2, Australia, 20 PP. Vega, A,, Lluch-Belda, D., Mucino, M., Leon, G., Hernandez, S., Lluch-Cota, D., Ramade, M. & Espinoza, G. (1997) Development, perspectives and management of lobsters and abalone fisheries off northwest Mexico, under a limited access system. In Developing and Sustaining World Fisheries Resources: The State of Science and Management (Ed. by D.A. Hancock, D.C. Smith, A. Grant & J.P. Beumer), pp. 1 3 M 2 . 2nd World Fisheries Congress Proceedings, Brisbane, 28 July-2 August, 1996, Australia. Zuboy, J.R. (1981) A new tool for fishery managers: the delphi technique. N. Am. J . Fish. Manage. 1, 55-9. ~

Part 3 Aquaculture and Marketing

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 25

Prospectus for Aquaculture J. KITTAKA

Research Institute for Marine Biological Science, Research Institutes for

Science and Technology, The Science University of Tokyo, Nemuro City, Fisheries Research Institute. Hokkaido 087-0166, Japan

J.D. BOOTH

National Institute of Water and Atmospheric Research, P . 0 . Box 14-901,

Kilbirnie. Wellington 6003, New Zealand

25.1

Introduction

Spiny lobsters are highly valued seafood and form extremely important fisheries in many countries. However, most fisheries are fully exploited or overexploited, and one of the few ways to expand production is through aquaculture. The greatest hurdle in the commercial culture of spiny lobsters is the difficulty in growing species through all their larval stages. Large-scale larval culture of spiny lobsters has still not been achieved despite significant advances in recent years. However, because spiny lobsters mature and breed in captivity, and because they grow communally, it seems likely that their commercial culture will be possible in the medium term. This chapter, which updates that of Kittaka & Booth (l994), examines progress, problems and future directions in the aquaculture of spiny lobsters. Many of the issues raised are taken up in more detail in the chapters which follow. Successful larval rearing to metamorphosis remains the achievement of just a few organizations, but optimal conditions for juvenile ongrowing in several species have now been broadly determined and some preliminary economic assessments made. Lobster physiology is now better known as many lobsters are delivered live to market, Still, little work has been directed towards essential technical design for large-scale commercial production.

25.2

Phyllosoma culture

Commercially important Panulirus species occur in tropical and subtropical waters. In Japan, there have been phyllosoma culture trials of P. japonicus for more than 50 years by prefectural fisheries experimental stations located along the Pacific coast washed by the warm Kuroshio Current. Other important genera are the cooltemperate Palinurus and Jasus. With the objective of achieving for the first time the culture of phyllosomas through all stages, Kittaka organized expeditions to North Atlantic coasts in 1979 (Kittaka, 1981), the South Atlantic in 1982 (Kittaka, 1984), and Australia and New Zealand in 1985 (Kittaka, 1987). He introduced Palinurus elephas from Ireland and France, Jasus lalandii from South Africa, and Jasus 465

466 Spiny Lobsters: Fisheries and Culture edwardsii and J . verreauxi from New Zealand and Australia for phyllosoma culture experiments at Sanriku, north Japan, where the ambient water temperature was suitable for these cool-temperate species. Phyllosomas are often referred to as delicate animals with an amazing life history in the wild and heavy mortality in culture. The first time any palinurid species was cultured through its entire larval development was in 1986/87, when Kittaka (1988) grew J . lalandii. The larvae were raised in a culture of microalga Nannochloropsis oculata and fed mussel (Mytilus edulis) gonad. The microalgae controlled nutrients and bacterial growth during the long phyllosoma development in a technique previously developed for prawn culture (Hudinaga & Kittaka, 1966, 1967). Using this method, the production of huge numbers of post-larvae has made penaeid shrimp culture a large aquaculture industry in several countries. The present status of phyllosoma culture is similar to that of penaeid larval culture in its early phase in the 1940s when post-larvae were cultured in small numbers using small containers up to tens of litres in volume (Hudinaga, 1942). In the commercialization of penaeid culture, there were two breakthroughs: (1) in 1960, the first use of 2 t tanks with the supply of the cultured diatom Skeletonema costatum as food; and (2) in 1964, the use of 100 t tanks with the penaeid larvae grown in a culture of wild diatoms and zooplankton (Hudinaga & Kittaka, 1967). Present phyllosoma culture containers have a capacity of less than 100 litres, so further development is required before similar scales of production are achieved for palinurids. Mussels are nutritionally satisfactory for phyllosomas. All species so far cultured to settlement, including P . japonicus, have been grown from the mid- and late phyllosoma stages on a diet of mussel gonad (Kittaka, 1988; Kittaka & Ikegami, 1988; Kittaka et al., 1988, 1997; Kittaka & Kimura, 1989; Yamakawa et al., 1989; Tong et al., 1991; Sekine, 1996; Moss, 1997). It appears that mussel gonad contains the essential amino acids and fatty acids necessary for phyllosoma development. Brine shrimp, however, have been used extensively in the culture of early phyllosoma stages. Cultured adult brine shrimp gave 80% survival to stage VIII phyllosomas of J . edwardsii before infection killed most of the larvae (Tong et al., 1991), suggesting that further improvement is required to enrich this food nutritionally for later stages (Nishimura, 1983). Nevertheless, J. verreauxi have now been grown to metamorphosis entirely on diets based on brine shrimp (G.A. Moss, NIWA, Wellington, pers. comm.). Larvae of fish, particularly cold-water species, are also nutritionally satisfactory for phyllosomas. Survival rate was improved for J . edwardsii, and the period of phyllosoma development shortened for P . elephas, by feeding with fish (Arctoscopus japonicus) larvae compared with feeding mussel gonad. Analyses of A. japonicus larvae showed high lipid content, particularly highly unsaturated fatty acids. Icosapentaenoic acid and docosahexaenoic acid content were 38 300 and 37 000 ng/ mg dry weight, respectively, while for Artemia nauplii they were much lower, at 4700 and 76 ng/mg dry weight, respectively (Ishikawa, Teshima & Kittaka, unpubl.).

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However, the use of mussels, Artemia and fish larvae as food will be difficult in large-scale culture and will probably be replaced by artificial feed. Much more work is needed here. An artificial food must be attractive to the phyllosomas, the phyllosomas must be able to snare it with their pereiopods, and the food must not break down in the water too much before it is eaten. A microencapsulated artificial food made up primarily of plant protein, lipid and carbohydrate was readily accepted by mid-stage J . edwardsii: the phyllosomas survived for 110 days and three moults (Otowa & Kittaka, unpubl.). The water-purifying activity of microalgae may be particularly important where artificial foods are used. Tank design is crucial. The tank should allow the larvae to remain in suspension but not cause physical damage. Loss of appendages, particularly the fourth and fifth pereiopods, can severely inhibit feeding and hasten the spread of infection. The tanks used most successfully so far have many tiny pores in the base to create circular water flow (Hughes et al., 1974; Illingworth et af., 1997). Development of large-scale tanks therefore requires hydrodynamic as well as biological considerations. Maintaining clean tanks is important. Problems experienced in phyllosoma tank culture include the formation of a bacterial film on the surface of the tank and the fouling of mesh screens with food remains which need to be periodically removed. A recirculating system with filtration through coral sand proved to control bacterial numbers more effectively than did the N . ocufata culture system, but there was no improvement in phyllosoma survival. Other water-quality issues need addressing: coral sand contains organic materials combined with calcium. Two-chambered tanks allow one chamber to be cleaned without the larvae being handled. Differences in hardiness of larvae within marine crustacean families is common (Kittaka, 1977). The best results for the larval culture of any palinurid species so far achieved have been with J . verreauxi, which may be the most primitive among Jasus species (George, 1969). Survival to puerulus stage of this species was around lo%, a rate similar to that of several commercially cultured prawns. At Sanriku during 1987-93, 168 pueruli of J . verreauxi (Kittaka et al., 1997) and 16 of J. edwardsii from New Zealand (Kittaka, Ono, Onoda & Booth, unpubl.), one each of J. edwardsii from Australia (Kittaka et af., 1988), J. lalandii from South Africa (Kittaka, 1988) and P . efephas from Europe (Kittaka & Ikegmi, 1988) and two P . japonicus from Japan (Kittaka & Kimura, 1989) were produced. Most mortality occurred at the early phyllosoma stages, probably through bacterial infection (Igarashi et al., 1990). In New Zealand, both J . edwardsii and J. verreauxi have now also been cultured to settlement in small numbers. Phyllosoma development takes place over many months: it took 64-132 days for P . efephas (Kittaka & Ikegami, 1988; Kittaka, 1997), 189-359 days for J. verreauxi (Kittaka et af., 1997), 303-319 days J . edwardsii (Kittaka, Ono, Onoda & Booth, unpubl.), 306 days for J . lalandii (Kittaka, 1988) and 304-391 days for P.japonicus (Kittaka & Kimura, 1989; Yamakawa et af., 1989). It may be possible to reduce these times by improved feeding and culture conditions. Culture of P . efephas, with the shortest larval period, appears particularly attractive for aquaculture. However, their

468 Spiny Lobsters: Fisheries and Culture survival rate during the phyllosoma stage was extremely low, perhaps because the nutritional requirement is different from that of other species. Disease is an ever-present problem in aquaculture. The density of phyllosoma larvae, and amount and type of feed, are important factors in the spread of pathogenic infections (see Chapter 29).

25.3

Puerulus culture

Mortality of cultured pueruli is high during and just after metamorphosis. Successful culture of phyllosomas to settlement has allowed the non-feeding status of the puerulus stage to be recognized for the first time (Kittaka & Kimura, 1989). This was evident by the atrophy of the mouthparts and foregut at the puerulus stage, while these organs are functional for feeding during phyllosoma and juvenile stages (Nishida et al., 1990). Nutrition during the non-feeding puerulus stage appears to depend entirely on nutrients stored during the preceding phyllosoma stages. The source and utilization of energy in the puerulus will be more readily clarified once mass culture is in place. The glaucothoe (metamorphosed form) of the king crabs Paralithodes camtschaticus and P . brevipes are similarly non-feeding (Abrunhosa & Qttaka, 1997a, b), and because they are easily mass cultured (Kittaka, 1999), glaucothoe may be a useful substitute for pueruli in laboratory experiments concerning the mechanism of coastal recruitment during the non-feeding metamorphosed stage.

25.4

Juvenile growout

The ongrowing of pueruli and small juveniles to market size has been viewed as more routine than phyllosoma culture. Lucrative markets exist in Japan, south-east Asia and Europe for whole live lobsters at least 200-300 g in weight. Several spiny lobster species have now been grown in captivity from puerulus or small juvenile to this weight. Optimum values for some factors, which affect growth and survival, such as water temperature, have been reported for several species and, since our last review, there have been significant additions to the literature. These have led to a broader understanding of optimal growing conditions for several commercially important species, more detailed knowledge of lobster physiology and some preliminary assessments of economic feasibility of lobster ongrowing. Nevertheless, knowledge of the optimal conditions for growout of juvenile spiny lobsters is still fragmentary and experimental results are sometimes contradictory. Pueruli and early juveniles are still not available from larval rearing in sufficient numbers for commercial ongrowing and most information has come from lobsters captured in the wild. New devices to capture pueruli in the wild continue to be developed, most being based on those used in studies of larval recruitment (Phillips

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469

& Booth, 1994) and some modified to take larger catches. The 30 000 P . argus pueruli taken around Antigua by a small number of collectors in 1 year (Lellis, 1990) is apparently still the record, but pueruli are also taken in large numbers in marine farms such as mussel farms. Late-stage phyllosomas and pelagic pueruli might be taken using large towed nets and purse-seine nets, or in nets moored in currents. The impact of removing pueruli from the sea has still not been well estimated for any fishery because of the difficulties of studying this cryptic stage in its often turbulent natural world. Conflict with the wild fishery is likely, particularly in years of low settlement. However, if survival of recently settled pueruli in nature is low, which seems likely, then the removal of some pueruli for ongrowing could result in greater overall production. The capture and ongrowing of wild-caught pueruli and small juveniles is still, however, conducted on only a small commercial scale. Probably the largest of these enterprises is in New Zealand, where thousands of pueruli and newly settled juveniles are collected for commercial ongrowing on shore in a ‘biologically neutral’ exchange for quota retired from the commercial fishery. An approach being considered in Australia is the return to the sea of some animals, particularly females, after culture to a larger size, to appease those who object to the removal of wild pueruli. It is likely, however, that in the long term pueruli cultured from eggs rather than taken in the wild will generally be more acceptable, and will also lead to a more regular and predictable supply of stock. Spiny lobsters are mainly tolerant and hardy animals. Their major advantage over clawed lobsters is that they are communal, and cannibalism is much less of a problem. Indeed, spiny lobsters often grow more rapidly in groups than in isolation. Ongrowing juveniles have therefore been viewed as relatively straightforward and growth rates exceeding those in the wild can be achieved. However, work published since our last review shows that ongrowing juveniles with high growth and survival is not always easy. It appears that several species can be cultured from puerulus to 200 g in 2 years (some in 1 year) and 300 g in less than 3 years, but the authors are more cautious about the prognosis for economic success for juvenile ongrowing than they were in 1994. Growth rates seen in the wild have not always been achieved in tanks. In addition, temperate species do not grow anywhere near as quickly, either in the wild or in captivity. Sourcing appropriate feeds, control of disease, and high infrastructure and labour costs also appear to be problematic, more so than had been previously thought. Food conversion ratios have often been poor. Disease outbreaks and high mortalities have occurred, particularly in recirculating systems with water-quality problems. There is still no suitable artificial feed. The most optimistic predictions for economic success tend to come from low labour cost economies using fast-growing tropical species. Successful commercial production of slower growing species may eventually come from shore culture for the first few months, followed by less expensive sea-cage ongrowing of the lobsters to market size.

470 Spiny Lobsters: Fisheries and Culture

Finding an effective food will be a major constraint in the development of commercial growout of spiny lobsters. Spiny lobsters are rather inefficient feeders; wet weight food conversion ratios (wet weight food c0nsumed:increase in body weight) between 3.6:l and 22:l have been reported with natural foods. Food may make up 50% of production costs, so the feeding level that optimizes growth rate and conversion efficiency needs to be found. Food must be high in nutritional value and acceptable to the lobsters, available all year round at reasonable cost, and easy to store and handle. Spiny lobsters will feed well on a wide range of natural marine foods, but natural items generally do not satisfy all of these requirements. Little work has been done on artificial diets, yet artificial diets will probably be more dependable and convenient to use than natural foods because of fewer problems with collection, seasonal variation in quality, and storage and handling. Not all crustacean reference diets have been useful for palinurids, although some prawn and fish diets appear promising. The development of measures of nutritional condition of the lobsters will continue to facilitate feed trials. Because natural exoskeletal colour is important in several markets, its maintenance in cultured juveniles may require the addition to the diet of carotenoid pigments such as astaxanthin. In the wild, spiny lobsters appear relatively free from disease and infection, but they may be subject to a range of disorders when intensively cultured. This has been found to be particularly the case for juveniles grown in recirculating systems with water-quality problems. Problems include build-up of external growths, infection of damaged limbs, fungal disease, bacterial shell disease, infection by Vibrio spp., and bacterial, nematode and ciliate infestation of the gills. Contributing factors include warm temperatures, stress, poor water quality and inadequate nutrition. Death at moulting, often with symptoms consistent with moult death syndrome (MDS) of homarids, has now been widely reported among captive spiny lobsters. Causes of MDS may include stress and poor nutrition, but may also be related to the protein source. It appears that casein-based diets for spiny lobster will require the addition of phosphatidylcholine to avoid MDS. Stressed animals also require extra oxygen and are susceptible to disease. Intrusions such as bright lights, unnecessary movement and handling (particularly near the moult) are all stressful. Indicators of stress used for crustaceans include haemolymph lactate, glucose, protein, hormone, ion, and pH levels, and rate of oxygen uptake. Although much less of a problem than in clawed lobsters, cannibalism is common among spiny lobsters, especially where there is shortage of food or shelter. Moulting or just moulted animals are most vulnerable. Panulirus spp. show remarkable growth after eyestalk ablation. For example, juvenile P. homarus homarus can be cultured to 200 g with good survival 5-6 months after ablation, and can double that weight in a further 2-4 months. This growth is three to seven times that of animals not ablated. Eyestalk ablation increases not only the moult frequency, but also the feeding rate and food conversion efficiency. However, survival of ablated lobsters of other species is often much lower than for

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471

those not ablated. Furthermore, the suitability for live sale of lobsters without eyes is unclear. Other techniques for enhancing growth of spiny lobster remain poorly explored. Potential techniques include the use of moulting and other hormones, electrical stimulation of moult, manipulation of feeding and other behaviour using light, and the management of moulting by the ‘downstream’ positioning of lobsters. Large-scale growout involves not only biological considerations but also technical factors: the design of facilities and the efficient use of space and water. These have been reported for clawed lobsters, but not all of these systems will be useful for spiny lobsters. Basic designs for lobster culture tank system designs for Panulirus spp. have been published. Because of disease problems, particularly in recirculated water systems, and because of the high costs associated with shore culture, sea cages may be an alternative for some situations. Enclosures are much less expensive than constructing ponds or tanks, do not need special infrastructure or costly maintenance, and can be easily moved. In a few places, larger lobsters (which may be below or above legal size) are captured for either shore or sea-cage ongrowing (‘fattening’) to market size, or for holding over for shorter periods to attain higher market return. While these methods have been practised for many years in countries such as India, they are quite new to places like Australia. There is the need for further appraisal of the economics of juvenile growout for each candidate species. Enough is known of the costs and likely returns for several species to allow preliminary evaluations to proceed. For J. edwardsii in Australasia to be profitable, there must be greatly reduced infrastructure and operating costs than at present, as well as lowered feed and labour costs, and lower lobster mortality.

25.5

Conclusions

Spiny lobster larval culture has progressed after much trial and error, in a similar manner to early penaeid larval culture. Culture to the puerulus stage has now been achieved for several spiny lobster species, but only small numbers of pueruli have been produced. Commercial-scale production of pueruli is therefore unlikely in the short term, and it is unclear how economic commercial larval culture can ever be, because of the long larval period. Genetic selection for desirable characteristics can follow once routine culture from the egg is achieved. This may be most rapid with the tropical Panulirus spp. which begin to breed when young, have more than one brood per year and have a short incubation period. Over the past 20 years there has been a great increase in biological information concerning growout conditions for juvenile spiny lobsters. It appears that several spiny lobster species can be ongrown from puerulus or small juvenile to market size in 1-2 years or less. Optimal culture conditions with regard to several factors are now broadly known for several species. However, ongrowing trials reported since

412 Spiny Lobsters: Fisheries and Culture

our last review have revealed problems, including high costs associated with puerulus capture, higher than expected incidence of disease, and high food and infrastructure costs. Commercial lobster production, after culture through all stages to commercial size, is still many years off.

References Abrunhosa, F.A. & Kittaka, J. (1997a) Functional morphology of mouthparts and foregut of the last zoea, glaucothoe and first juvenile of king crabs Paralithodes camtschaticus, P . brevipes and P. platypus. Fish. Sci., 63, 74654. Abrunhosa, F.A. & Kittaka, J. (1997b) Morphological changes in the midgut, midgut gland and hindgut during the larval and postlarval development of the red king crabs Paralithodes camtschaticus. Fish. Sci., 63, 923-30. Hudinaga, M. (1942) Reproduction, development and rearing of Penaeus japonicus, Bate. Jap. J. ZOO^., 10, 305-93. Hudinaga, M. & Kittaka, J. (1966) Studies on food and growth of larval stage of a prawn, Penaeus japonicus, with reference to the application to practical mass culture. InJ Bull. Planktol. Jpn. 13, 83-94. Hudinaga, M. & Kittaka, J. (1967) The large scale production of the young Kuruma prawn, Penaeus japonicus Bate. Inf Bull. Plankrol. Jpn. Commemoration Number of Dr. Y.Matsue, 546. Hughes, J.T., Shleser, R.A. & Tchobanoglous, G. (1974) A rearing tank for lobster larvae and other aquatic species. Prog. Fish. Cult., 36, 129-32. Igarashi, M.A., Kittaka, J. & Kawahara, E. (1990) Phyllosoma culture with inoculation of marine bacteria. Nippon Suisan Gakkaishi, 56, 17814. Illingworth, J., Tong, L.J., Moss, G.A., & Pickering, T.D. (1997) Upwelling tank for culturing rock lobster (Jasus edwardsii) phyllosomas. Mar. Freshwar. Res., 48, 91 1-14. Kittaka, J. (1977) Recent progress in penaeid shrimp culture. Acres Colloques du C.N.E.X.O., 4, 193-202. Kittaka, J. (1981) Ecological survey on lobster Homarus americanus and H . gammarus along the coasts of the North Atlantic Ocean. Report to the Ministry of Education, Culture and Science (Grant-in-Aid for Overseas Scientific Survey, No. 404152 and 504347), 77 pp. (in Japanese). Kittaka, J. (1984) Ecological survey of lobster Homarus along the coasts of the Atlantic Ocean: Ecology and distribution of Homarus capensis along the South Atlantic Ocean. Report to the Ministry of Education, Culture and Science (Grant-in-Aid for Overseas Scientific Survey, No. 56042009, 57041052 and 58043052), 118 pp. Kittaka, J. (1987) Ecological survey of rock lobster Jasus in southern hemisphere: Ecology and distribution of Jasus along the coasts of Australia and New Zealand. Report to the Ministry of Education, Culture and Science (Grant-in-Aid for Overseas Scientific Survey. No. 59042013, 60041066 and 61043061), 232 pp. Kittaka, J. (1988) Culture of the palinurid Jasus lalandii from egg stage to puerulus. Nippon Suisan Gakkaishi, 54, 87-93. Kittaka, J. (1997) Culture of larval spiny lobsters: a review of work done in northern Japan. Mar. di Freshwat. Res., 48, 923-30. Kittaka, J. (1999) Biological characteristics of Paralithodes camtschaticus and P.brevipes and their implication in marine restocking. In Strategies for Revival of Marine Fisheries in Cold Waters

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(Ed. by J. Kittaka, Y. Deguchi, H. Hirata & F. Yamazaki), pp. 83-1 10. Kouseisha-Kouseikaku, Tokyo, Japan (in Japanese). Kittaka, J. & Booth, J.D. (1994) Prospectus for aquaculture. In Spiny Lobster Management (Ed. by B.F. Phillips, J.S. Cobb & J. Kittaka), pp. 365-73. Blackwell Scientific Publications, Oxford, UK. Kittaka, J. & Ikegami, E. (1988) Culture of the palinurid Palinurus elephas from egg stage to puerulus. Nippon Suisan Gakkaishi, 54, 1149-54. Kittaka, J. & Kimura, K. (1989) Culture of the Japanese spiny lobster Panulirus japonicus from egg to juvenile stage. Nippon Suisan Gakkaishi, 55, 963-70. Kittaka, J., Iwai, M. & Yoshimura, M. (1988) Culture of a hybrid of spiny lobster genus Jams from egg stage to puerulus. Nippon Suisan Gakkaishi, 54,413-17. Kittaka, J., Ono, K. & Booth, J.D. (1997) Complete development of the green rock lobster, Jasus verreauxi from egg to juvenile. Bull. Mar. Sci., 61, 57-71. Lellis, W.A. (1991) Spiny lobster a mariculture candidate for the Caribbean? World Aquacult., 22( I), 60-3. Moss, G. (1997) Rearing rock lobster larvae. Aquacult. Update, Spring, 13. Nishida, S., Quigley, B.D., Booth, J.D., Nemoto, T. & Kittaka, J. (1990) Comparative morphology of the mouthparts and foregut of the final stage phyllosoma, puerulus, and postpuerulus of the rock lobster Jasus edwardsii (Decapoda, Palinuridae). J . Crust. Biol., 10, 293-303. Nishimura, M. (1983) Studies on larval production of Ise lobster-I. A. Rep. Mie PreJ Hamajima Fish. Exp. St., (1981), 6 6 9 . (in Japanese). Phillips, B.F. & Booth, J.D. (1994) Design, use, and effectiveness of collectors for catching the puerulus stage of spiny lobsters. Rev. Fish. Sci., 2, 255-89. Sekine, S. (1996) Present status on phyllosoma culture. Saibai (Marine Farming), 74, 22-6 (in Japanese). Tong, L.J., Pickering, T.D., Illingworth, J. & Paewai, M.P. (1991) Rock lobster culture. In MAF Fisheries Marine Research Annual Report 1990-91. NZ Ministry of Agriculture and Fisheries. Yamakawa, T., Nishimura, M., Matsuda, H., Tsujigado, A. & Kamiya, N. (1989) Complete larval rearing of the Japanese spiny lobster Panulirus japonicus. Nippon Suisan Gakkaishi, 55, 745.

SPINY SPINY L0BSTERS:FISHERIES L0BSTERS:FISHERIES AND AND CULTURE CULTURE B.F. B.F. PHILLIPS&J. PHILLIPS&J. KITTAKA KITTAKA CoDvriaht 00 2000 Cowriaht 200 bv bv Fishina Fishina News News Books Books

Chapter 26

Maturation K.NAKAMURA

Faculty of Fisheries, Universiiy of Kagoshima, 4-50-20 Shimoaruta,

Kagoshima-shi 890-0056, Japan

26.1

Introduction

Maturation and reproductive mechanisms in spiny lobsters have only been studied in a few species in detail. Several descriptions of their reproduction biology, basic information on the sexual maturity, annual cycles of reproduction, spawning time and fecundity have come mainly from data on the fisheries’ resources. The available knowledge related to brood stock control comes from rearing experiments accompanied by physiological studies designed to clarify the reproductive processes and the factors controlling them.

26.2

Reproductive system

The reproductive system of the Japanese spiny lobster Panulirus japonicus possesses similar structures to those of other Palinuridae and Nephropidae species. The external and internal reproductive organs as well as the arrangement of the genital apertures were described for P . penicillutus (Matthews, 195l), P . japonicus (Okamura, 1956) and Jusus lalandii (Paterson, 1968).

26.2.1

Male

The internal reproductive system of male P . japonicus is shown in Figure 26.1. The matured testis is a semitransparent or slightly yellowish organ, forming elongated lobes which are much smaller than the ovary of females. It is located on the median dorsal of the midgut gland, beneath the heart. It is H-shaped, similar to that in other lobsters (Fielder, 1964; Farmer, 1974; Hunter et al., 1996), with two anterior lobes extending to the dorsolateral stomach, and two posterior lobes lengthening backwards to the first abdominal segment. The posterior lobes lie between the dorso-abdominal muscle situated superficially and main segmental masses of the ventral abdominal muscles in parallel with the midgut. The paired vasa deferentia arise from each posterior lobe and pass downwards to an opening pore at the coxopodite of the fifth pereiopod. The opening site is provided with a special apparatus which is an ammonitoid protuberance. The tip portion is slightly raised as its axis is not parallel to the basal 474

Maturation

475

OD

Fig. 26.1 Male and matured female reproductive systems in the Japanese spiny lobster Punulirus juponicus. Upper: dorsal view (male body weight, 132 g; carapace length, 52 mm). Middle: ventral view (male body weight, 186 g; carapace length, 57 mm). Lower: dorsal view (female body weight, 200 g; ovary weight, 19.7 g; carapace length, 61 mm). The testis (T) sends out the vas deferens (VD) which connects to the ammonitoid apparatus (VA) at the coxopodite of the fifth pereiopod (CP). The ovary (OV) shows an H-shape, sending laterally the oviduct (OD) from the median level of the ovarian length.

plane of the proximal whirlpool. The degree of its sclerotization seems to decrease according to ageing of the male; in the intermoult male of 188 g body weight [carapace length (CL) 63 mm] it is completely sclerotized and pigmented like the hard exoskeleton of the thoracic sternum and pereiopod. However, in more aged and larger males, the apparatus is not as hard and pigmented as the neighbouring cuticle. Its arthrodial membrane is slightly thicker than that of the ventral abdomen. This organ was described as an epicuticular rim in the male J. lalandii (Paterson, 1968; Silberbauer, 1971b). However, in P . juponicus the male gonopore is still obscure, although it has been indicated to be at the distal of the apparatus (Okamura, 1956). The author’s histological observation in P . japonicus (Nakamura, 1993) has revealed that it opens at the bottom of the peripheral invagination inside the apparatus, similarly to the case of the epicuticular rim in J. lalundii. The above-mentioned characteristic of the apparatus observed in the young male seems to be unsuitable for copulation if it functions as a genital apparatus. However, it is possible that its hardness and shape change during the moult, which precedes copulation, and this post-moult male with a soft cuticle would copulate. In the case of aged and larger

476 Spiny Lobsters: Fisheries and Culture males there is a possibility that its distal portion of the apparatus is broken at copulation because two males of 400 g and 750 g (CL 80 mm and 90 mm) had the partially repaired apparatus of its medial portion near the tip. It is possible to divide the vas deferens into three parts: (1) a proximal portion of the highly coiled tube; (2) an intermediate portion of the thick tube of which the initial part is helical; and (3) a distal ejaculatory portion of the slender tube. The spermatophores seem to be produced in the secretory area of these proximal and intermediate vasa deferentia and stored there until copulation. In the case of P . elephas, the distal ejaculatory portion greatly enlarges and the spermatophores are stored therein (Hunter et al., 1996). The testis yields not only spermatids but also nutrient cells observable in the spermatophores. The swollen tube of the intermediate vas deferens changes its diameter according to the maturation cycle (Minagawa & Higuchi, 1997), owing to the quantity of internal matrix embedding the sperms. 26.2.2

Female

The internal reproductive system of female P . japonicus is shown in Figure 26.1. The ovary is located dorsally on the midgut gland, beneath the heart. It is H-shaped, similar to that in other lobsters (Fielder, 1964; Farmer, 1974; Talbot, 1981; Juinio, 1987; Hunter et al., 1996). Its anterior lobes extend to the cephalic area with their tips turning upwards. Its posterior lobes, in the matured condition, elongate to the fourth abdominal segment, parallel to the midgut. The posterior lobes differ in length from each other, the left one commonly being longer. An oviduct derives from the middle level of the ovary length on each side, posterior to the lobe connecting the two halves. It is a semitransparent and slender tube, and opens to the coxopodite of the third pereiopod. There is no genital apparatus at that opening site, differing from the case of the vas deferens. The thelycum is absent, as in J. lalundii (Paterson, 1968) but unlike Nephropidae species. There are a few reports on ovarian development during maturation in spiny lobsters. The ovary is externally white or weakly yellow in the immature condition, and changes to reddish orange or dark orange (Minagawa & Sano, 1997) in the completely mature condition. According to the stage of ovarian development, its shape and size will also change. However, detailed studies related to these processes are extremely limited (Minagawa & Sano, 1997). The author previously investigated this during the breeding season to reveal the relationship between the ovary’s weight and its maturation condition. The value for the gonadosomatic index was 9.5% in a fully matured female (200 g body weight, 61 mm CL).

26.3

Histology of the ovary and developmental oocytes

In P . japonicus, the histological structure of the ovary is as follows. The ovarian wall is composed of two layers, one a superficial connective tissue supplied with blood

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Fig. 26.2 Developmental process of ova in the Japanese spiny lobster Punulirus japonicus. Follicular cells are omitted in these figures. Scale bar = 125 pm; em, egg membrane; vo, vacuole; yg, yolk granules. Each combination of roman numeral and digit corresponds to the stage referred to in the text.

vessels and the other an inner germinal epithelium. Layers of the outer epithelium and smooth muscle are not prepared in this species, in contrast to other spiny or clawed lobsters (Bumpus, 1891; Herrick, 1909; von Bonde, 1936). The connective tissue varies periodically in thickness according to ovarian maturation. For example, its thickness decreases from 0.13 to 0.04 mm in individuals of 150-200 g body weight. The germinal epithelium forms inward folds running through the ovarian length, from which ova grow. They are enveloped in a single layer of flat cells, i.e. follicular cells. However, these follicular cells are difficult to be seen histologically until a certain developmental stage. Matured ova reach around 0.5 mm in diameter. Developmental stages of the ovary have been assigned by different researchers on the basis of oocyte size, ovary size and ovary colour. There are seven macroscopic stages for J . edwardsii and J. lalandii (= J. edwardsii) (Fielder, 1964), five for P . penicillutus (Juinio, 1987), and six for P . homarus rubellus (Berry, 1971) and P . elephas (Hunter et al., 1996).

478 Spiny Lobsters: Fisheries and Culture Development of the oocytes in P . japonicus may be classified morphologically into three phases or six stages in haematoxylin-eosin histological preparations (Fig. 26.2). Z Non-vitellogenesis phase: this is an initial and immature stage of development. The maximum diameter of oocytes is 120-130 pm. Each nucleus is around 30 pm, and contains commonly a nucleolus as well as dispersed chromatin. The cytoplasm is stained with haematoxylin. ZZ Primary vitellogenesis phase: this phase is divided into three stages. (1) The oocyte and nucleus diameters are 13&140 pm and 40-50 pm, respectively. The cytoplasm is haematoxylin positive, possessing a few vacuoles peripherally. (2) The diameters of the oocyte and nucleus are around 150 pm and 40-50 pm, respectively. The cytoplasm reduces its haematoxylin-positive character and becomes eosinophilic. The peripheral vacuoles increase distinctly in number and are distributed around the nucleus. (3) The maximum diameter of the oocytes is around 250 pm, with the nucleus of 40-50 pm diameter. Eosinophilic granules appear at the peripheral cytoplasm among the distributed vacuoles. The egg membrane appears between the oocyte and follicular cells. IZZ Secondary vitellogenesis phase: this phase corresponds to a period of yolk accumulation. It may be divided into two stages. (1) The oocytes have a diameter range of 260-480 pm and a nucleus of about 20 pm. In the cytoplasm, yolk appears abundantly as eosinophilic granules. (2) The maximum diameter of the oocytes reaches about 500 pm. The nuclei decrease in size and finally become difficult to see. The thickness of the egg membrane is measured as 4-8 pm. This stage corresponds to the completely mature period of the oocyte. The above-mentioned classification in P . juponicus needs to be examined in detail before its application to other species. Recently, light- and electron-microscopic observations detailed oogenesis and ovarian development in P . japonicus (Minagawa & Sana, 1997), and eight substages were distinguished.

26.4

Size at maturity

For P . japonicus, only female minimum size at maturity has been reported, with a CL of 38 mm (Inoko et al., 1979). In other cases, it corresponded to 42 mm CL and a body weight of 80 g, at which individuals were assumed to be 1.5-2 years old after the puerulus larvae (Ino, 1947; Kanamori, 1988) or 41.8 mm CL as the estimated size at 50% maturity (Minagawa, 1997). In P . homarus homarus, a value of 3 8 4 7 mm was reported and the size at onset of oviposition was estimated as 59.5 mm, both as rostra1 CL (Jayakody, 1989). For other female Punulirus, the CL at first maturity was 86 or 69 mm in P . argus (Evans et al., 1995; Pollock, 1997) and 59 mm in P . guttatus (Evans et al., 1995). In P . longipes longipes, the smallest females with eggs and mature ovaries were 41.8 and 41.4 mm CL, respectively (Gomez et al., 1994).

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479

For female P. gilchristi, the minimum size at maturity was 55 mm CL (Pollock & Augustyn, 1982; Pollock, 1997). For female J . lalandii on the west coast of South Africa, the minimum size at maturity was reported as 45 mm or 55-59 mm CL (Matthews, 1962; Heydorn, 1965; Pollock, 1997). For J . edwardsii, the value was between 70 and 97 mm (Bradstock, 1950). This size is known to vary according to a distribution difference of habitat, even when comparing the same species (Street, 1969). For example, female J. lalandii at Queap Bay in South Africa were significantly smaller (53.0 mm) at 50% maturity than those at the higher latitudes of Dassen Island (59.5 mm), Elands Bay (59.9 mm) and Olifantsbos (59.5 mm) (Cockcroft & Goosen, 1995). In J . edwardsii from east and west localities off North Island, New Zealand, the above values for females were 75-79 and 65-69 mm, respectively (Annala et al., 1980). Further, in P. penicillatus the values were 43 mm in the Saudi Red Sea (Hogarth & Barratt, 1996), 40.8 mm in the Philippines (Juino, 1987), 50 mm in the Gulf of Aqaba (Plaut, 1993) and 62 mm in Enewetak, Marshall Islands (Ebert & Ford, 1986). Practically, the body weight, total length, CL and rostra1 CL can be used as the maturity index. However, these indices are available only during the breeding season. An ovigerous setae method seems valid, although the estimated size at 50% maturity would be a little smaller than that obtained by an ovigerous female method (Groeneveld & Melville-Smith, 1994). As for internal indices of the maturity, the increased weight of the testis including accessory genital organs such as the vas deferens is useful in some species (Lindberg, 1955; Heydorn, 1969). In females, the weight, size and colour of the ovary indicate the maturation condition; the ovary changes from the immature colour of creamy white to light orange, then darker orange, and finally brick red in both Jusus and Panulirus species (Fielder, 1964; Berry, 1971).

26.5

Spawning time

The typical annual reproductive cycles of female spiny lobster are different among species. From the results of the ovary condition, two spawnings per year are indicated in P. japonicus (Ino, 1950). Of large females with over 47 mm CL, 93% were estimated to spawn twice during the spawning season (Minagawa, 1997). The natural spawning season of this lobster in Japan shows a tendency towards earlier spawning at lower latitudes with higher water temperature in winter, and its range shortens according to the increase in latitude (Inoue, 1981). This season in Japan ranges from early April to early October except in the southern area, Okinawa (Deguchi, 1988). At Okinawa, the spawning season ranges from early January to late October, with its zenith from early May to mid-June. For P. longipes Zongipes in the Philippines, at least two broods of individuals in rapid succession were reported, particularly during the warmer months of March to

480 Spiny Lobsters: Fisheries and Culture May (Gomez et al., 1994).For P . penicillatus in the Gulf of Aqaba, Red Sea, females spawned two to four times during the reproductive season from February to October (Plaut, 1993). For P . homarus rubellus in South Africa and P . polyphagus in the Indian Ocean, three to four broods were yielded annually (Berry, 1971; Kagwade, 1988). However, J . edwardsii in New Zealand and P . delagoae and P . gilchristi in South Africa produced only one brood (Sorensen, 1969; Berry, 1973; Groeneveld & Rossouw, 1995). From these references, it is considered that maturation of all spiny lobsters as well as their oviposition occur at least once in early summer, although there may be a few exceptions, then a second spawning follows, with intervals of 2.5-7 months according to the reproductive cycle of the lobster. It may be possible to regulate the spawning time by controlling the water temperature of the brood stock. This idea is supported by data on the effect of temperature on the moulting and spawning of the Japanese spiny lobster (Table 26.1) (Deguchi, 1988).

26.6

Copulation and spawning behaviour

For the Japanese spiny lobster, copulation behaviour has been reported in the laboratory (Nagai, 1956) and the procedure was as follows. In mid-May two males and three females were reared in a 16-21°C aquarium with dimensions of 78 x 52 x 70 cm. These sizes were not mentioned. All females were considered to have attained a mature condition, because examination of a dead specimen showed a completely ripe ovary. On 29 May, one female was found to be carrying eggs in the morning. A mucous substance of milky white spermatophore adhered to the ventral surface of its thorax. In the case of P . elephas, two spermatophores were normally deposited on either side of the distal portion of the female’s sternum, below the genital openings (Hunter et al., 1997). From the early morning of the previous day, the female had been observed combing the long and simple setae on each endopodite of the swimmeret with the fifth chelipeds. On the afternoon of 2 June, frequent combing occurred, and a male pursued the female at 21.00 h. The female escaped on several occasions but they finally clung together and copulation took place at 22.50 h. They were in an erect posture, being in contact along the ventral surface of the thorax. It took about 25 s from start until body separation after completion. Such copulation by the same pair occurred four times with 20 or 35 min intervals. The time required for copulation was always within 30 s. At 3.37 h on 3 June, the female spawned. The female supported her body axis perpendicularly, using the aquarium wall as a prop. Such a posture seems to be general among the spiny lobsters (Berry, 1970). The fourth to sixth segments of the abdomen were flexed and the expanded tail fan covered the gonopore. All swimmerets formed bilaterally temporary side-screens, as if to prevent the loss of extruded eggs. It took about 20 min to carry out the spawning. However, the zenith

Maturation

48 1

Table 26.1 Comparison of time schedules of moulting and spawning in the Japanese spiny lobster reared at water temperatures of 20°C and 25°C Year and conditionsa Critical dates 1986 WT 25°C CL6.8 cm BW 295 g 1986 WT 25°C CL 6.7 cm BW 270 g 1987 WT 20°C CL 4.2 cm BW 163 g 1987 WT 20°C CL 5.9 cm BW 314 g 1987 WT 20°C CL 4.6 cm BW 174 g

30 April

31 May

6 July

Moulting Spawning Hatching 7 May 8 June 12 July

Moulting 8 March

Spawning Hatching 7 May 9 May

3 August

Moulting

29 May

12 July

Moulting Spawning Eggs dislodged Eggs dislodged Moulting 6 May 26 June 25 July

Moulting Spawning Eggs dislodged 4 July 20 May 24 June

Moulting Spawning Died while carrying eggs

From Deguchi (1988). WT, water temperature; CL, carapace length; BW, body weight.

of oviposition seemed to have occurred within 10 min. This egg extrusion also took less than 1 h in P . homarus (Berry, 1970); however, it took 2-5 h in J . lalundii and J . edwardsii (von Bonde, 1936; Sorensen, 1969; Silberbauer, 1971a). Another male and the females in the same aquarium did not show any positive response to the activities during the above-mentioned behaviour of the couple.

26.7

Effect of eyestalk ablation

Regarding the endocrine control of spiny lobster maturation, a few studies have reported on eyestalk ablation experiments in P . argus and P . hornarus (Quackenbush & Herrnkind, 1981; Radhakrishnan & Vijayakumaran, 1984). The results indicated the presence of the moult and ovary-inhibiting factors in the eyestalk.

482 Spiny Lobsters: Fisheries and Culture The author investigated the physiological relation between the eyestalk and ovarian maturation in P . japonicus. Within 2 weeks after eyestalk ablation in early summer (water temperatures of 24-30"C), some of the females of 150-200 g body weight spawned. The number of eggs ranged from 90 000 to 120 000, which is less than the value in other Palinuridae species. For example, 300 000 eggs were reported in P . argus of 75 mm CL (Squires & Riveros, 1978). However, the number is reported to vary according to female body size. In P.japonicus, it ranges from 29 000 to 554 000 for female body lengths of 12.0-25.4 cm (Ino, 1947). The other females did not spawn or in several cases died. The oocytes in the ovary of the non-spawned individuals were at the secondary vitellogenesis phase, accompanying yolk reabsorption. Another non-spawned female of 244 g body weight had entered a pre-moult stage. Its gonadosomatic index was 0.61% and the ova were at the primary vitellogenesis phase. From these results, it can be deduced that the eyestalk not only relates to the ovary-inhibiting mechanism but also is involved in the physiological integration of the moulting metabolism and ovarian development.

26.8

Discussion

For crustacean rearing, similarly to other aquaculture, it is very important to have a basic knowledge of the biology of the species, especially information on growth and maturation. However, most attempts at mariculture of spiny lobsters have been made with insufficient information. This is due to a deficiency of basic data relating to the breeding physiology, because of the slow growth rate of spiny lobsters. Physiological data are as yet too fragmentary to reveal fully the maturation process and the mechanisms in spiny lobsters. The species-specific and geographical differences observed in the annual reproduction cycle of spiny lobsters suggest the necessity for a new approach from a comparative standpoint.

References Annala, J.H., McKoy, J.L., Booth, J.D. & Pike, R.B. (1980) Size at the onset of sexual maturity in female Jasus edwardsii (Decapoda: Palinuridae) in New Zealand. N.Z. J. Mar. Freshwat. Res., 14, 217-27. Berry, P.F. (1970) Mating behaviour, oviposition and fertilization in the spiny lobster Panulirus homarus (Linnaeus). Oceanogr. Res. Inst. (Durban) Invest. Rep., 24, 1-16. Berry, P.F. (1971) The biology of the spiny lobster Panulirus homarus (Linnaeus) off the east coast of southern Africa. Oceanogr. Res. Inst. (Durban) Invest. Rep., 28, 1-75. Berry, P.F.(1973) The biology of the spiny lobster Palinurus delagoae Barnard, off the coast of Natal, South Africa. Oceanogr. Res. Inst. (Durban) Invest. Rep., 31, 1-27. Bonde, C. von (1936) The reproduction, embryology and metamorphosis of the Cape crayfish (Jusus lakundii) (Milne-Edwards) Ortman. Invest. Rep. Fish. Mar. Biol, Surv. Div. S. Afr., 6, 1-25.

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Bradstock, C.A. (1950) A study of the marine spiny crayfish Jasus lalandii (Milne-Edwards), including accounts of autotomy and autopsy. Zool. Publ. Victoria Univ. CON.,7, 1-38. Bumpus, H.C. (1891) The embryology of the American lobster. J. Morphol., 5, 215-62. Cockcroft, A.C. & Goosen, P.C. (1995) Shrinkage at moulting in the rock lobster Jasus lalandii and associated changes in reproductive parameters. S. Afr. J. Mar. Sci., 16, 195-203. Deguchi, Y. (1988) Copulation and spawning; Japanese spiny lobster. In Seed Production of Decapod Crustaceans (Ed. by R. Hirano), pp. 64-75. Koseisya-Koseikaku, Tokyo (in Japanese). Ebert, T.A. & Ford, R.F. (1986) Population ecology and fishery potential of the spiny lobster Panulirus penicillatus at Enewetak Atoll, Marshall Islands. Bull. Mar. Sci., 38, 5 M 7 . Evans, C.R., Lockwood, A.P.M., Evans, A.J. & Free, E. (1995) Field studies of the reporductive biology of the spiny lobsters Panulirus argus (Latreille) and P. gutratus (Latreille) at Bermuda. J. Shellfish Res., 14, 371-81. Farmer, AS. (1974) Reproduction in Nephrops norvegicus (Decapoda: Nephropidae). J. Zool., 174, 161-83. Fielder, D.R. (1964) The spiny lobster, Jaws lalandii (H. Milne-Edwards), in South Australia. 11. Reproduction. Aust. J. Mar. Freshwat. Res., 15, 1 3 3 4 . Gomez, E.D., Juinio, M.A.R. & Bermas, N.A. (1994) Reproduction of Panulirus longipes longipes in Calatagan, Batangas, Philippines. Crustaceana, 67, 1 10-20. Groeneveld, J.C. & Melville-Smith, R. (1994) Size at onset of sexual maturity in the South Coast rock lobster Palinurus gilchristi (Decapoda: Palinuridae). S. Afr. J. Mar. Sci., 14, 219-23. Groeneveld, J.C. & Rossouw, G.J. (1995) Breeding period and size in the South Coast rock lobster, Palinurus gilchristi (Decapoda: Palinuridae). S. Afr. J. Mar. Sci., 15, 17-23. Herrick, F.H. (1909) Natural history of the American lobster. Bull. U S . Bur. Fish., 29, 149408. Heydorn, A.E.F. (1965) The rock lobster of the South Africa west coast, Jasus lalandii (H. MilneEdwards). I. Notes on the reproductive biology and the determination of minimum size limits for commercial catches. S. Afr. Div. Sea Fish. Invest. Rep., 53, 1-32. Heydorn, A.E.F. (1969) Notes on the biology of Panulirus homarus and on length/weight relationship of Jasus lalandii. S. Afr. Div. Sea Fish. Invest. Rep., 69, 1-26. Hogarth, P.J. & Barratt, L.A. (1996) Size distribution, maturity and fecundity of the spiny lobster Panulirus penicillatus (Oliver 1791) in the Red Sea. Trop. Zool., 9, 399408. Hunter, E., Shackley, S.E. & Bennett, D.B. (1996) Recent studies on the crawfish Palinurus elephas in South Wales and Cornwall. J. Mar. Biol. Ass. U.K., 76, 963-83. Ino, S . (1947) Spawning fecundity and spawning time in Panulirus japonicus De Haan. Nippon Suisan Gakkaishi, 13, 32-3 (in Japanese). Ino, S. (1950) Observation on the spawning cycle of Ise-ebi Panulirus japonicus v. Siebold. Nippon Suisan Gakkaishi, 15, 725-7 (in Japanese). Inoko, Y., Kawanishi, M., Hirata, S . & Takaba, M. (1979) Release and research of Gazami larvaeIX. Fisheries and resources analysis concerning the 50’ release group at Edajima Bay. Rep. Hiroshima Pref. Fish. Inst., 10, 51-5 (in Japanese). Inoue, M. (1981) Studies on breeding of phyllosoma larvae of the Japanese spiny lobster. Rep. Fish. Res. Inst. Kanagawa Pref., 1, 1-91 (in Japanese). Jayakody, D.S. (1989) Size at onset of sexual maturity and onset of spawning in female Panulirus homarus Crustacea Decapoda Palinuridae in Sri Lanka. Mar. Ecol. Prog. Ser., 57, 83-8. Juinio, M.A.R. (1987) Some aspects of the reproduction of Panulirus penicillatus (Decapoda: Palinuridae). Bull. Mar. Sci., 41, 242-52. Kagwade, P.V. (1988) Reproduction in the spiny lobster Panulirus polyphagus (Herbst). J. Mar. Biol. Assoc. India, 30, 3746. Kanamori, K. (1988) Studies on fisheries managements and resource ecology of Ise-ebi in the Kinann area at Wakayama Pref. Rep. Wakayama Pref. Fish. Inst., 109-209 (in Japanese). Lindberg, R.G. (1955) Growth, population dynamics, and field behavior in the spiny lobster, Panulirus interruptus (Randall). Univ. C a l g Publ. Zool., 59, 157-248.

484 Spiny Lobsters: Fisheries and Culture Matthews, D.C. (1951) The origin, development and nature of the spermatophoric mass of the spiny lobster, Panulirus penicillatus (Oliver). Pac. Sci., 5, 359-71. Matthews, D.C. (1962) The rock lobster of South West Africa, Jams lalandii (Milne-Edwards). Size frequency, reproduction, distribution, and availability. S. W.Afr. Mar. Res. Lab., Invest. Rep., 7, 1-66. Minagawa, M. (1997) Reproductive cycle and size-dependent spawning of female spiny lobsters (Panulirus japonicus) off Oshima Island, Tokyo, Japan. Mar. Freshwat. Res., 48, 869-74. Minagawa, M. & Higuchi, S. (1997) Analysis of size, gonadal maturation, and functional maturity in the spiny lobster Panulirus japonicus (Decapoda: Palinuridae). J. Crust. Biol., 17, 70-80. Minagawa, M. & Sano, M. (1997) Oogenesis and ovarian development cycle of the spiny lobster Panulirus japonicus (Decapoda: Palinuridae). Mar. Freshwat. Res., 48, 875-87. Nagai, H. (1956) Copulation and spawning behaviours observed in Panulirus japonicus. SuisanZosyoku, 4, 9-1 I (in Japanese). Nakamura, K. (1993) Structure of male accessory apparatus related to the gonopore in the Japanese spiny lobster. Bull. Jpn SOC.Sci. Fish., 59, 1489-93. Okamura, S. (1956) Anatomy of the Experimental Animals, pp. 141-71. Kazama-Syobou, Tokyo, Japan (in Japanese). Paterson, N.F. (1968) The anatomy of the cape rock lobster, Jasus Ialandii (H. Milne-Edwards). Ann. S. Afr. Mus., 51, 1-232. Plaut, I. (1993) Sexual maturity, reproductive season and fecundity of the spiny lobster Panulirus penicillatus from the Gulf of Eilat (Aqaba), Red Sea. Aust. J. Mar. Freshwat. Res., 44, 527-35. Pollock, D.E. (1997) Egg production and life-history strategies in some clawed and spiny lobster populations. Bull. Mar. Sci., 61, 97-109. Pollock, D.E. & Augustyn, C. (1982) Biology of the rock lobster Palinurus gilchristi with notes on the South African fishery. Fish. Bull. S. Afr., 16, 57-73. Quackenbush, L.S. & Herrnkind, W.F. (1981) Regulation of molt and gonadal development in the spiny lobster, Panulirus argus (Crustacea: Palinuridae): effect of eyestalk ablation. Comp. Biochem. Physiol., 69, 523-7. Radhakrishnan, E.V. & Vijayakumaran, M. (1984) Effect of eyestalk ablation in the spiny lobster Panulirus homarus 3. On gonad maturity. Indian J . Fish., 31, 209-16. Silberbauer, B.I. (1971a) The biology of the South African rock lobster Jasus lalandii (H. MilneEdwards). I. Development. S. Afr. Div. Sea Fish. Invest. Rep., 92, 1-70. Silberbauer, B.I. (1971b) The biology of the South African rock lobster Jasus lalandii (H. MilneEdwards). 2. The reproductive organs, mating and fertilisation. S . Afr. Div. Sea Fish. Invest. Rep., 93, 1-46. Sorensen, J.H. (1969) The New Zealand rock lobster or marine spiny crayfish Jaws edwardsii (Hutton): distribution, growth, embryology and development. N.Z. Mar. Dep. Fish. Tech. Rep., 29, 1 4 6 . Squires, H.J. & Riveros, G. (1978) Fishery biology of spiny lobsters Panulirus argus of the Guajira Peninsula of Colombian South America 1969-1970. Proc. Natl. SheNfish. Assoc., 68, 63-74. Street, R.J. (1969) The New Zealand crayfish Jasus edwardsii (Hutton, 1875): an account of growth, moulting and movements in southern waters, with notes on reproduction and predators. N.Z. Mar. Dep. Fish. Tech. Rep., 30, 1-54. Talbot, P. (1981) The ovary of the lobster, Homarus americanus. I. Architecture of the mature ovary. J. Ultrastruct. Res., 76, 23543.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 27

Breeding

A.B. MACDIARMID

National Institute of Water and Atmospheric Research, P . 0 . Box

14-901 Kilbirnie, Wellington 6003, New Zealand I

J. KITTAKA

Research Institute for Marine Biological Science, Research Institutes for

Science and Technology, The Science University of Tokyo, Nemuro City, Fisheries Research Institute, Hokkaido 087-0166, Japan

27.1

Introduction

Continuing interest in the aquaculture of spiny lobsters has been sustained by high market prices and heavy fishing of most natural stocks. While wild puerulus and juveniles are likely to be reared initially, ultimately two factors will bring about the establishment of captive breeding programmes. First, as natural stocks come under increasing pressure fishers are unlikely to agree to large-scale removal of pueruli or juveniles from the wild. Secondly, there will be strong economic incentives to establish breeding programmes using individuals with commercially desirable attributes as brood stock. While the 6-12-month duration of the larval phase has been seen as the main hindrance to captive breeding, successful mating and egg extrusion by adults is also critical. Learning to recognize and control the timing and duration of reproduction are the first goals of captive breeding so that phyllosoma larvae can be produced year round if required. A longer term goal will be the selective breeding of individuals with the fastest growing or most disease-resistant larvae and juveniles. There has been a substantial increase in the understanding of the reproductive biology and behaviour of palinurids in the two decades since the publication of review papers by Aiken & Waddy (1980), Atema & Cobb (1980), Kanciruk (1980) and Phillips et al. (1980) in The Biology and Management of Lobsters. Field and laboratory studies have proliferated partly in response to these reviews but also because of recent interest and success in breeding and rearing palinurids in captivity. Direct field studies have been important in clarifying aspects of earlier laboratory observations of reproductive activities and have suggested fruitful areas for further experimental investigation in the laboratory. Advances have been made in understanding the factors important in controlling the onset and duration of breeding of palinurids, and comprehensive descriptions of courtship, mating, oviposition and egg bearing now exist for a range of species in the genera Palinurus, Panulirus and Jasus. This chapter first reviews the reproductive behaviour of spiny lobsters as it applies to breeding in captivity and then reviews the culture conditions found to be 485

486 Spiny Lobsters: Fisheries and Culture successful for breeding a variety of species in breeding programmes and experiments in Japan, India, Australia, South Africa, New Zealand and the USA.

27.2

27.2.1

Reproductive behaviour Mating

Interval between moulting and mating

In spiny lobsters mating occurs some time after the mature female moults, providing her with fresh ovigerous setae on the endopods of the pleopods, on to which the eggs will later attach, and ensures that the moult does not occur during the egg-carrying period. However, there is no requirement for females of any species to be in the soft shell condition for successful mating to occur (Paterson, 1969a; Chittleborough, 1976). In some tropical species a second mating takes place either before or after before the release of larvae from the previous brood (Creaser, 1950; Gregory et al., 1982; MacFarlane & Moore, 1986; Juinio, 1987; Briones-Fourzan & LozanoAlvarez, 1992). The interval between moulting and mating is highly variable within and between species. In Panulirus cygnus the two events may be separated by 2 or up to 97 days (Chittleborough, 1976). In Jams species mating occurs between 2 h and 63 days after moulting, with smaller females mating sooner after moulting but later in the reproductive season than larger females (von Bonde, 1936; Paterson, 1969b; McKoy, 1979; Arana et al., 1985, MacDiarmid, 1989a). For J. edwardsii in Wellington, New Zealand, the day of mating can be predicted by the equation: Julian day of mating = 81.51 + (0.61 x Julian day of moulting) - (0.11 x female CL in mm), where the Julian day

=

day of year (r2 = 0.65) and CL

=

carapace length.

Female mating window

In Jasus species, which have a short-lived spermatophore (see below), egg extrusion by females must immediately follow mating. Consequently, the female must find a male to mate when her crop of eggs is ripe and ready to be extruded. How long are they in this condition? Is it a matter of hours, days or weeks? Experiments on J . edwardsii in New Zealand, where females were presented with males before, on or up to 20 days after the predicted day of mating (see above), indicate that peak fertility is achievable only within a narrow period of a day or two. Females presented with males 5 days after the predicted day of mating suffer a 55% reduction in fertilization, while after 10 days’ delay only 2% of the eggs remain viable (MacDiarmid, unpubl. data). In other species, such as P . cygnus, females may also be at peak fertility for only a short period, but because the male deposits a long-lived spermatophore (see

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below) the window of opportunity for mating may be as long as 69 days before egg extrusion (Chittleborough, 1976). In terms of breeding programmes, Jasus females need access to males only when their ovaries are fully ripe, whereas for species with a long-lived spermatophore males may be supplied at any stage in the month or so before egg extrusion. Peak egg ripeness may be detectable by hormonal blood assays, but as this is still unproven in spiny lobsters, in practice males should be introduced well before egg extrusion is anticipated. Environmental control of spawning

Photoperiod and temperature are the prime environmental controls of reproduction in Crustacea (Sastry, 1983). Latitudinal trends in reproduction in some species of spiny lobster strongly suggest that these factors are important (Kanciruk, 1980). For example, the Japanese spiny lobster P . japonicus inhabits the rocky shore washed by the warm Kuroshiwo Current. Their northern limit is in the Chiba Prefecture in the middle part of Japan and their southern limit is in Okinawa Prefecture, although they occur occasionally off Taiwan and the Philippines. The spawning season of P . japonicus begins early in the year (winter/spring) in southern Japan, where mean winter sea temperature is higher, and becomes gradually later (spring/summer) further north. However, the reproductive season ends in mid-September to October in all localities (Oshima, 1942; Ino, 1950; Nonaka, 1988). In the southern temperate spiny lobster J . edwardsii, New Zealand populations in cooler water at 46"s mate as early as late February (late summer) (Street, 1969), while in warmer water populations at 36"s mating first occurs in late May (late autumn) (MacDiarmid, 1989a). Tropical species such as P . gracilis P . inflatus, P . versicolour and P . penicillatus may breed more or less continuously throughout the year (MacDonald, 1982; Juinio, 1987; Briones-Fourzhn & Lozano-Alvarez, 1992). Laboratory experiments have determined that long days enhance female gonadal development and spawning frequencies in P . argus (Lipcius & Herrnkind, 1987) while warmer temperatures significantly accelerate these processes in P . cygnus, P . argus and P . japonicus (Chittleborough, 1976; Lipcius & Herrnkind, 1987; Deguchi, 1988; Nonaka, 1988; Deguchi et al., 1991). Male mating success

Mating in both the field and laboratory typically is preceded by intermale aggression, which in extreme cases may lead to an agonistic embrace lasting for several minutes and loss of limbs or death of the smaller male. This results in a polygynous mating system with the largest males doing the most mating (Berry, 1970; Lipcius, 1985; MacDiarmid, 1989b). Smaller males, unable to mate, may moult (Lipcius, 1985). Experimental removal of the largest male in laboratory tanks enables one of the smaller mature males to begin courting females (MacDiarmid, 1989b). In general, for successful copulation to occur the male must be at least as

488 Spiny Lobsters: Fisheries and Culture large as the female. Males in pre-moult stages will not participate in reproductive activities and must be replaced with a male in intermoult. In temperate species of spiny lobster in which most mature males moult well outside the reproductive period this is only an occasional problem. However, for tropical species in which mating activity occurs more or less continuously throughout the year this is a more common problem if only one male is provided per breeding tank. Determination of moult state is quickly achieved by removing a pleopod tip and examining it under a lowpower microscope, using the criteria of Lyle & MacDonald (1983) to assign the correct stage. Female choice

Mate choice by female J. edwardsii varies with their moult stage and reproductive state. Experiments in large outdoor tanks (100 m3) indicate that pre-moult and eggbearing females display no particular preference for empty shelters or shelters occupied by large or small males, or by other females. In contrast, post-moult, preovigerous females show strong selection for shelters containing the largest male available (MacDiarmid, unpubl. data). Female choice may also occur when unmated females approach mature males (e.g. Lipcius et al., 1983; Lipcius & Herrnkind, 1985) or during the early phase of courtship if females reject or flee from searching males (Lipcius & Herrnkind, 1985; MacDiarmid, 1989b). Female rejection of a male may not be possible in laboratory tanks and may lead to forced copulations (Lipcius et al., 1983). Females may become less selective in their choice of mate if they near the time of egg extrusion and no reproductively active male has been provided (Lipcius & Herrnkind, 1985, 1987). This is less likely to be a problem in species which deposit a long-lived spermatophore (see later) because the lengthy period between moulting and oviposition allows ample opportunity to introduce acceptable mates (Lipcius & Herrnkind, 1985). In Jams species, however, because the short-lived nature of the spermatophore (see later) determines that copulation must immediately precede egg extrusion, the timely choice of mate is crucial. Male choice

Male spiny lobsters have a limited supply of sperm (see below) and may be selective in the females that they mate. Female quality is variable, most obviously as a function of size. Larger females are either good survivors or fast growers, both evolutionary desirable qualities from the males’ (and the selective breeders’) perspective and have larger clutches of eggs available to be fertilized than do smaller females (see below). Moreover, recent experiments have determined that large female J. edwardsii have 20% larger eggs than small females, and hatch 20% larger larvae, which survive nearly 40% longer in median lethal dose (LDS0) starvation experiments (MacDiarmid, Kendrick & Stewart, unpubl. data). Laboratory choice experiments show that large male J . edwardsii prefer to cohabit with large

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post-moult pre-ovigerous females than with very small females, whereas small males display no such choice (MacDiarmid, unpubl. data). From a controlled breeding perspective this suggests that smaller females may remain unmated if large males have a choice of larger females to mate. Courtship

A distinct pre-copulatory courtship phase may last from several minutes to days, and in the laboratory has been observed up to 50 days before copulation (Lipcius & Herrnkind 1985). The male typically takes up a position in front of the female close enough to enable each lobster to touch the antennules and anterior body of the other (Fig. 27.1). As courtship progresses antenna1 touching and scraping increase in frequency and intensity until the female emerges from cover. The female is then pursued by the male and confronted head on. The female may then tail-flip away to shelter and the process is repeated or the copulatory phase may begin. Copulation

The basic process of copulation has been well described in four palinurid species; J . edwardsii, P . argus, P . japonicus and P . homarus rubellus (Nagai, 1956; Berry, 1970; McKoy, 1979; Lipcius et al., 1983; Lipcius & Herrnkind, 1985, 1987; MacDiarmid, 1987; Deguchi, 1988). In brief, the male and female move very close in the frontal approach position and rear up so that each is supported by the other, sternum to sternum, while standing on their fifth pereiopods and gripping the other’s body anteriorly with the other pairs of pereiopods. Still embracing with the ventral

Fig. 27.1 The frontal approach, typical of male (nearest camera) spiny lobsters (in this case Jasus edwardsii) during the early phase of courtship.

490 Spiny Lobsters: Fisheries and Culture surfaces apposed, the pair normally overbalances with the female uppermost. In male J . edwardsii the fifth pair of walking legs is tightly embraced around the female. Deposition of an external spermatophore from the gonopores at the bases of the fifth pair of walking legs on to the sternum of the female occurs within 5-90 s. Copulation ends with the female tail-flipping under shelter and the male righting himself. Mating in these four species is most co-operative in Jasus and least so in P. hornarus, but the differences are only in the degree to which agonistic behavioural elements are used in mating. Mating and aggression in spiny lobsters share some common postures (Atema & Cobb, 1980; Lipcius et al., 1983) and both behaviours peak in frequency at the same time of year (Berry, 1970; Lipcius & Herrnkind, 1985, 1987; MacDiarmid, 1989a, b). A frontal rush in P . homarus when the male attempts to lift and embrace the female (Berry, 1970), and the vertical embrace in all four species, use behavioural elements seen only during the most intense of agonistic interactions, usually between rival mature males (Atema & Cobb, 1980; MacDiarmid, 1989b). The extent to which confinement in laboratory tanks produces the high levels of male aggression and female submission during mating observed in P. homarus is unknown, but it is likely that females could evade aggressively approaching males in nature. Multiple mating

Up to four copulations by a single pair have been reported in J . edwardsii, P . argus and P . japonicus (Lipcius et al., 1983; Kittaka, 1987; Deguchi, 1988; Deguchi et al., 1991). Pairs copulated between one and four times at night. Lipcius et al. (1983) suggested that repeated copulations were necessary to lay down successive layers of the spermatophore (basal adhesive, middle sperm matrix and outer protective layers), but this seems unlikely given the arrangement of spermatophoric material in the distal end of the vas deferens (e.g. Matthews, 1951; Berry & Heydorn, 1970; Radha & Subramoniam, 1985). Alternatively, successive copulations may be required before a spermatophore is successfully ejaculated and attached to the female’s sternum (e.g. Deguchi, 1988; Deguchi et al., 1991). Multiple copulations of a female prior to spawning, as evidenced by up to three overlaying viable spermatophores, have been reported in three species of palinurid (Mota Alves & Paiva, 1976; Shaklee, 1983; Lipcius, 1985). In P. argus and P. luevicauda the frequency of multiple copulation reaches 43% and increases with female size (Mota Alves & Paiva, 1976). It is unknown whether the layered spermatophoric mass results from residual partially used spermatophores (often found in P . argus; Kanciruk & Herrnkind, 1976) deposited before previous egg-bearing periods, overlaid by a fresh spermatophore, or successive copulations by the same or different males before a single spawning, and whether all layers contribute equally to fertilization, but these factors are important to captive breeding programmes. Mota Alves & Paiva (1976) suggested that the larger females seek multiple copulations because more sperm is required to ensure fertilization of their eggs.

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Spermatophore

The spermatophore is deposited externally on the posterior two sternal plates of the female during copulation in the genera Panulirus, Palinurus and Jasus, and probably also in Linuparus and Puerulus (Nagai, 1956; Paterson, 1969a, b; Berry & Heydorn, 1970; Kittaka, 1987; MacDiarmid, 1988). It is composed of a basal adhesive layer, an internal gelatinous matrix containing the spermatozoa and in most species an outer protective crust which may turn brown or black after a few days’ exposure to seawater (Berry & Heydorn, 1970; Radha & Subramoniam, 1985) (Fig. 27.2). In Jams the spermatophore lacks the hard outer protective layer found in other genera and disintegrates within hours of exposure to seawater (Paterson, 1969; Berry & Heydorn, 1970; Kittaka, 1987). The size of the spermatophore deposited by the male varies depending on a number of factors. Laboratory experiments show that in P . argus there is a linear, positive relationship between the size of the female and the area the spermatophores deposited by a large male (MacDiarmid & Butler, 1999). Smaller males have less capacity to vary the size of their spermatophore and the trend of spermatophore size against female size is rather flat for these males (MacDiarmid & Butler, 1999). Prior matings can also deplete the amount of sperm that males have available to ejaculate (Mauger, unpubl. data) and therefore decrease the size of successive spermatophores after several ejaculations (Butler, unpubl. data). In P . argus large spermatophores may cover 22 cm2 and weigh over 11 g,

Fig. 27.2 Large female Panulirus argus from the Dry Tortugus, Florida, showing a new dark spermatophore on the sternum and a developing clutch of eggs fertilized by a previous spermatophore. Photograph by L. Cox.

492 Spiny Lobsters: Fisheries and Culture while the smallest spermatophores are 3 cm2 in area and weigh only 0.5 g (MacDiarmid, unpubl. data).

21.2.2

Fertilization and oviposition

Interval between copulation and oviposition

In the genus Jasus, in which males deposit a short-lived spermatophore, egg extrusion immediately follows successful copulation (Paterson, 1969a; Berry & Heydorn, 1970; McKoy, 1979; MacDiarmid, 1988). In other genera, where the spermatophore has an outer hard protective layer (Berry & Heydorn, 1970), egg extrusion may be delayed by as little as 10 min after copulation as in P . japonicus (Nagai, 1956; Deguchi, 1988; Deguchi et al., 1991) or as long as 69 days as in P . cygnus (Chittleborough, 1976). Female pre-spawning behaviour

In all genera in which the spermatophore has a hard protective layer, the female scrapes this away with the dactylus of the fifth walking leg up to 3 days before oviposition (Berry, 1970). Before oviposition the female uses the chelae of her fifth walking legs to ‘comb’ or ‘groom’ the ovigerous setae attached to the endopodites of the pleopods (Nagai, 1956; Berry, 1970; Deguchi et al., 1991). The function of this behaviour is unclear but it may help to remove any broken setae or attached debris and stimulate the cement glands a t the base of the pleopods. Egg extrusion and fertilization

Egg extrusion is very similar in all six species in which it has been observed (Nagai, 1956; Silberbauer, 1971; McKoy, 1979; Aiken & Waddy, 1980; MacDiarmid, 1987; Deguchi, 1988; Deguchi et al., 1991). The female usually clings in a vertical head-up position either on a rock wall inside a shelter in the field or on an artificial shelter provided in laboratory tanks. She then forms a brood chamber by flexing her abdomen forwards beneath her body, extending the exopodite of the pleopods, and spreading her telson and uropods into a fan covering the genital apertures at the base of the third walking legs as in Jusus (McKoy, 1979) or the posterior part of the spermatophoric mass as in P . homarus (Berry, 1970). The eggs are then extruded from the genital apertures and are drawn by gravity, and a current caused by the beating of the endopodites of the posterior pleopods, over the spermatophore and down into the brood chamber. Fertilization occurs either as the eggs pass over the spermatophore or in the brood chamber as eggs and spermatozoa are swirled around by the beating of the pleopods. The fertilized eggs then attach to setae on the endopodite of the pleopods. Egg extrusion and attachment usually takes 16-50 min (Nagai, 1956; McKoy, 1979; Aiken & Waddy, 1980; MacDiarmid, 1987; Deguchi,

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1988; Deguchi et al., 1991) but in J. lalandii may take 3 4 h (von Bonde, 1936; Silberbauer, 1971). The entire spermatophore is generally used to fertilize a brood of eggs (Aiken & Waddy, 1980). Partially spent spermatophores are often observed on P. argus females (Kanciruk & Herrnkind, 1976). Although field data suggest that they are rarely used to fertilize more than one brood, on one occasion in the laboratory a single spermatophore was observed to fertilize two successive broods (Lipcius, 1985). Egg bearing

After oviposition is complete the female continues to flex her abdomen forwards and also lifts it slightly to enable her to move around. Viewed from above, the expanded fan of the uropods in a position just posterior to the fifth walking legs is characteristic of egg bearing. The pleopods beat slowly, probably to maintain oxygen supply to the eggs, and intermittently the abdomen is extended to allow the female to inspect or clean the eggs using the chelate fifth walking legs (Ansell & Robb, 1977). Any unfertilized eggs are removed, but sometimes in the laboratory part of an entire fertilized brood is lost. This may be due to stress or could be a response to infestations of the egg mass by fungi, nemertian egg predators, other parasites or bacterial infection (Silberbauer, 1971; Shields & Kuris, 1989). Removal of the remains of the external spermatophore occurs during this period in some species (Berry, 1970). The duration of egg bearing varies greatly among species and with temperature. In tropical species such as P. homarus egg bearing may last as little as 7-9 days at 29°C (Radhakrishnan, 1977; Nair et al., 1981), while in P. penicillatus and P. argus egg bearing lasts 20-30 days (McGinnis, 1972, cited in Juinio, 1987; Kanciruk & Herrnkind, 1976). In the subtropical P . cygnus females carry eggs for 19 days at 25°C but 68 days at 19°C (Chittleborough, 1976). In southern temperate Jasus species the incubation period lasts between 92 and 103 days at 15°C and 150 days at 11°C (Paterson, 1969a; MacDiarmid, 1989a). It can be reduced to as little as 60-65 days in captivity at temperatures over 18°C (Silberbauer, 1971; Kittaka et al., 1988). Female Palinurus elephas in cool Scottish waters carry eggs for over 200 days (Ansell & Robb, 1977). In P . japonicus the incubation period is 50 days at 21°C and 32 days at 25°C (Ino, 1950; Deguchi et al., 1991). In this species the relation between the duration of the egg-bearing period D (days) and mean water temperature T ("C) is shown by the formula (Oshima, 1942):

D = 152.0 - 4.75T(r = -0.96) Brood size

Female spiny lobsters brood a large number of small eggs, the amount varying depending on a number of factors and across species. Female body size is often the only variable considered. Brood size increases in female P . japonicus from 50 000

494 Spiny Lobsters: Fisheries and Culture eggs at 40 mm CL to 800 000 at 95 mm CL while in P . interruptus this higher number is not carried until a body size of 160 mm CL is reached (Nonaka, 1988). In J. edwardsii brood size is lower again with only 407 000 eggs produced at 157 mm CL (Annala & Bycroft, 1987). Over two million eggs are brooded by the largest spiny lobster, J. verreauxi (Kensler, 1967). In species that spawn more than once between moults brood size may decrease in successive broods (Creaser, 1950; Juinio, 1987). Female brood size may also vary dependent on the amount of sperm transferred by the male. This is often a function of male size, but the number of recent previous matings can also be important. In at least two species of spiny lobster, J . edwardsii and P . argus, small males do not generally transfer enough sperm to fertilize all the eggs that a large female can extrude, resulting in reduced rates of fertilization (MacDiarmid & Butler, 1999). This effect is exacerbated by any recent previous matings (MacDiarmid & Butler, 1999). Another factor affecting brood size in a female Jasus is her mating history. If she had no mate available in one year then ovarian scarring during egg resorption (see below) can limit the number of eggs produced by the ovaries in successive years (MacDiarmid, unpubl. data). Further information on brood size and fecundity is found in Chapter 14. Unmatedfemales

The effect of not providing mates for female spiny lobsters varies among genera. In P . argus, for example, any female that does not have a male available to mate will ultimately extrude her current batch of ripe eggs and start the next cycle of reproductive activity with little apparent additional loss of reproductive function (MacDiarmid & Butler, pers. obs.). Although the extruded and unfertilized eggs may adhere to the pleopodal setae for a few hours they soon dislodge or are removed by the female, leaving a white ropy residue adhering to the pleopods. In contrast, in female J . edwardsii the effect of not mating is more significant. Unmated females attempt to resorb eggs in the ovary, resulting in strong reddishpink staining of the haemolymph and muscle tissue with egg-derived pigments (Gibson & Frusher, 1997). They are also weak and lethargic, possibly because the large mass of eggs in the body cavity prevents feeding and normal organ function. In contrast, mated females which extrude a full batch of eggs have a clear white abdomen with normal coloured haemolymph (MacDiarmid, unpubl. data). One year after mating, female J. edwardsii normally have large ovaries packed with developing oocytes. In contrast, one year after their predicted day of mating, the ovaries of non-mated female J . edwardsii show evidence of scar formation with only small regions of normal egg development. Although most non-mated females will mate in the subsequent breeding season, their clutches are typically very small compared with normally breeding females (MacDiarmid, unpubl, data). Timely provision of mates for every female in a breeding programme is crucial for Jasus species but less important in other genera in which the signal for egg extrusion is independent of the mating event.

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495

Egg development

Freshly spawned eggs are spherical in shape and just after attachment are a fresh red colour and 0.5 mm in diameter in P . juponicus and pale yellow and about 0.8 mm in diameter in Jusus (Silberbauer, 1971). The fertilized eggs are centrolethical and the cells divide independently of the yolk. Embryonic development of P . juponicus is summarized in Table 27.1 (Shiino, 1950). Silberbauer (1971) used gross morphological changes as criteria for five stages of development in Jusus. The embryos develop into the nauplius stage within the egg before hatching as a brief lasting naupliosoma stage in Jams (MacDiarmid, 1985) or as stage I phyllosoma larvae in other genera. Egg size in J . edwurdsii varies as a function of female size (Kendrick & Stewart, unpubl. data). Eyed eggs from a 143 mm CL female are 0.78 mm2 in plan area, while those from a 75 mm CL female cover only 0.57 mm2. Tong et ul. (2000) derived a formula which enables the number of days to hatching for J . edwurdsii to be calculated once the eyes begin to form and can be measured to form an index (eye length x width/2): Days to hatch = where EAT

=

EAT at hatch (699) - EAT on day eye index measured Rearing teperature - Biological zero (7.53)

effective accumulated daily temperature ("C).

Number of broods

In temperate and subtropical species one annual brood is normal with a well-defined breeding season. Tropical species such as P. versicolour, P. injlutus, P . gracilis and P. Table 27.1 Embryonic development of Panulirus japonicus at 24°C Stage

I I1 I11 IV V VI VII VIII IX X XI From Shiino (1950).

Time after spawning Blastula Molura Blastodisc formation Pre-nauplius Nauplius Post-nauplius 7 pairs of appendages 1 1 pairs of appendages Pigmented ocellus Pigmented compound eye Pre-hatching

0-72 h 72-1 30 h 5.5-6.5 days 6.5-8 days 8-10 days I s 1 3 days 13-15 days 15-17 days 17-20 days 20-25 days 25-31 days

496 Spiny Lobsters: Fisheries and Culture penicillatus breed more or less continuously throughout the year and may have more than one brood between moults (MacDonald, 1982; Juinio, 1987; Briones-Fourzan & Lozano-Alvarez, 1992). In species with a wide latitudinal range such as P . argus and P . japonicus the number of broods generally increases from one to between two and four per year with decreasing latitude, but with some obvious regional variation (Ino, 1950; Kanciruk, 1980). In P . inflatus and P . gracilis the number of broods per year increases with body size (Briones-Fourzan & Lozano-Alvarez, 1992). The number of broods is also related to environmental influence. Only 12% of wild female P . cygnus spawned twice per year, while in the laboratory, with surplus food supply, 77% spawned twice annually. At elevated temperatures and abundant food females averaged three moults and six spawnings per year (Chittleborough, 1976).

27.2.3

Hatching

In the wild, egg-bearing females of many spiny lobster species migrate to the deep seaward edge of reefs or beyond on to deep sand flats, and may form aggregations consisting almost entirely of females to hatch their larvae (Berry, 1971; Ansell & Robb, 1977; Fonteles-Filho & Ivo, 1980; Herrnkind, 1980; Gregory et al., 1982; McKoy & Leachman, 1982; MacFarlane & Moore, 1986; MacDiarmid, 1991; Kelly et al., 1999). Captive females successfully hatch larvae in tanks just deep enough to allow the female to stand on the tips of her pereiopods, often on the side or top of the shelter, and extend the abdomen vertically into the water current (Silberbauer, 1971; MacDiarmid, 1985). Hatching occurs as the female violently beats the pleopods for a few seconds, releasing a ‘swarm’ of larvae which typically are strongly photopositive and swim towards the brightest light source. This behaviour can be used to concentrate newly hatched larvae at a convenient collection point and ensure that they move away from the water outlet. Knowing the daily timing of hatching allows prompt transfer of larvae from hatching tanks to rearing facilities. In J . edwardsii, the majority of eggs hatches at sunrise in both the laboratory and field (MacDiarmid, 1985). Beating of pleopods and associated hatching of larvae takes place at 1-2 min intervals for the first 15 min but continues intermittently for1 h. In other species anecdotal reports suggest that hatching occurs some time during the night (Silberbauer, 1971; Kittaka, pers. comm.). After the 3-5 days taken to complete hatching of a brood the female removes the empty egg cases and any remaining undeveloped eggs using the chelae of her fifth walking legs. This tears and breaks the ovigerous setae, resulting in a ragged fringe on the pleopods characteristic of the post egg-bearing stage (Silberbauer, 1971).

Breeding 27.3 27.3.1

497

Captive breeding Culture conditions

Tank size and shape

Spiny lobsters are very flexible in the style and size of tank in which they will successfully court and mate. Some workers have set up large (3500-4500 litre) naturalistic tanks with natural rock shelters, algae and benthos and a large viewing window (eg. Paterson, 1969a; Berry, 1970; McKoy, 1979), while others have used small (200-1000 litre) or very large (10 000 litre) concrete, fibreglass or plastic troughs, bare except for concrete block shelters (Chittleborough, 1976; Radhakrishnan, 1977; Lipcius & Herrnkind, 1985; MacDiarmid, 1989b; MacDiarmid & Butler, 1999) (Fig. 27.3). The size of the tank should reflect the size and numbers of breeding pairs. A 40-litre aquarium suitable for 300 g adult P . guttatus will not suit 4-5 kg J. verreauxi. Water quality

Although the water supply to breeding tanks has usually been a flow-through system, closed or partially closed recirculating systems have also been used successfully to breed spiny lobsters (e.g. Lipcius & Herrnkind, 1985, 1987; Kittaka, 1988). Spiny lobsters are sensitive to hypoxia and water flows need to be sufficient to support the biomass of lobsters in a tank at the culture water temperature. As

Fig. 27.3 Part of a flow-through seawater circulation system used to breed successfully 9 G 2 10 mm carapace length Jasus edwardsii. The circular concrete troughs measure 1.8 m x 0.6 m.

498 Spiny Lobsters: Fisheries and Culture oxygen saturation in seawater decreases and lobster metabolism increases with increasing temperature, water flows for the same biomass of lobsters needs to be higher for tropical species than for temperate species (Beard & McGregor, 1991; Crear & Forteath, 1998). Water entry pipes should be placed to ensure that water circulation close to the tank bottom is as vigorous as possible. Poor circulation here can lead to a build-up of chitinoclastic bacteria or fungi, resulting in blackening of the exoskeleton and necrosis of the cuticle (Evans & Brock, 1994). Aeration should be used to ensure good circulation in all parts of the tank and to enhance lobster survival in the advent of inevitable breakdowns in the main water circulation system. Although spiny lobsters will tolerate somewhat reduced salinities (Stead, 1973; Booth & Kittaka, Chapter 30) the water supply should be as close to oceanic salinities as possible to minimize stress to breeding animals. Care should be taken in recirculating systems that evaporation does not lead to hypersaline conditions. Ammonia is the main nitrogenous waste product of lobsters and can prove fatal if left to accumulate in systems with a low turnover of water. Water exchange high enough to maintain oxygen levels in flow-through systems will generally be sufficient to prevent build-up of ammonia (Beard & McGregor, 1991). Recirculation systems must have biological filters of sufficient volume to cope with the expected ammonia production. Light levels and shelter

The light levels should approximate that found in the natural habitat. If direct sunlight enters the tanks this can be achieved by a combination of shading at least half the tank surface with an opaque material (wood or plastic) and provision of shelters into which the lobsters can fully retreat. Hollow concrete building blocks or ceramic waste pipes are ideal. These structures are also crucial in providing vertical surfaces to which females in the process of egg laying can adopt the most suitable posture. Diet

A wide range of diets has been used successfully to condition and maintain brood stock. Live foods are the best as they can be feed ab libitium and will stay alive until eaten by the lobsters. In temperate localities with easy access to farmed mussels or wild clams, these make an ideal food (MacDiarmid, 1989b; MacDiarmid & Butler, 1999). In tropical localities fiddler crabs and bivalves have been used successfully (Radhakrishnan, 1977; Lipcius & Herrnkind, 1985, 1987). If obtaining sufficient live food is a problem, a combination of frozen squid and fish may be substituted with good results (MacDiarmid & Butler, 1999). Care should be taken not to underfeed lobsters as they rapidly loose breeding condition especially at high tropical water temperatures (MacDiarmid and Butler, pers. obs.). Correspondingly, attention should also be paid to prompt removal of any uneaten food as it will rapidly foul the tanks, especially in recirculation water systems.

Breeding

499

Brood stock

Egg-bearing females for use in aquaculture or hatching experiments can be obtained from the wild or by breeding lobsters in captivity. If wild ovigerous females are used as brood stock then hatchery sites and the culture species will be limited to those available locally, as transportation of berried females is difficult and often results in bacterial infection, causing severe loss of eggs or hatching of vulnerable phyllosoma larvae. Transportation of live males and females around the world is now a wellestablished commercial operation to supply live lobsters to Asian markets, and this same technology can be used to transport brood stock of any species. For example, for breeding experiments at Sanriku, in northern Japan, mature males and females of five northern and southern temperate species of spiny lobster were obtained from wild populations. The species were P. japonicus from Japan, P. elephas from France and Ireland, J . edwardsii from New Zealand and Australia, J. lalandii from South Africa and J. verreauxi from New Zealand. Specimens were transported by air and road in expanded foam boxes with coolant. They tolerated about 3 days’ travel without seawater at about 5°C for the cold temperate species of the genera Jasus and Palinurus and about 10°C for the temperate species of genus Panulirus. Mortality due to air transportation was usually very low unless flights did not connect properly in summer. Sex ratio

In wild populations there are normally many mature males for every female ready to mate, and operational sex ratios as high as nine males to every female during the peak of the mating season have been reported (MacDiarmid, 1989b). However, some males reside with multiple mature females during the mating period and probably secure many copulations (MacDiarmid, 1994). A 1:l sex ratio is not always ideal in captive breeding because of aggressive behaviour among males during the mating season will often result in limb loss and other injuries (e.g. MacDiarmid, 1989b). In captive breeding programmes sex ratios are usually skewed heavily towards females, with ratios of one to 12 females per male resulting in successful reproduction in different species (Berry, 1970; Chittleborogh, 1976; McKoy, 1979; Lipcius & Herrnkind, 1985, 1987; Gibson & Frusher, 1997; MacDiarmid & Butler, 1999).

21.3.2

Reproductive cycles in captivity

Panulirus japonicus

Mating experiments were conducted for seven successive years using two tanks initially stocked with a total of 20 females and five males in both tanks. The number of females and males decreased to 15 and two, respectively, after 6 years, owing to mortality. Mortality of males was higher than females because of aggressive

500 Spiny Lobsters: Fisheries and Culture interactions during the mating season. Mating occurred in June-July when about 70-80% of females carried eggs (Kittaka & Kimura, 1989). Sixteen of a total of 17 females mated successfully and carried eggs. Hatching of phyllosomas occurred from early July to mid-September with a peak in midJuly. The hatching period was late compared with wild populations because of lower water temperatures in the laboratory. Females moult once a year, sometime in a 6-month period following the reproductive season, while males moult twice per year, both before and after the mating period. Palinurus elephas

Mating experiments were conducted in Japan for 10 successive years (Kittaka & Ikegami, 1988). Two tanks were initially stocked with four females and two males. Six additional females were introduced later. In a 10-year period, mortality was about 50% for both males and females. Aggressive behaviour between males was observed. Males moulted mainly in the period November to February, prior to the females which moulted between March and May. Frontal approaches characteristic only of courting behaviour occurred from September to November. Egg-bearing females were first found in September. Eggs hatched between late January and April. Approximately 40 000 phyllosomas hatched from each female. This species carries larger but fewer eggs than species in the genera Panulirus and Jams (Kittaka & Ikegami, 1988; Kittaka & Kimura, 1989). Jasus edwardsii and Jasus lalandii

Both species have similar moulting and mating schedules in the wild and in captivity in the southern hemisphere. Females moult in autumn (March to early June), mate 9-40 days later, inversely dependent on size, carry eggs during the austral winter and spring and hatch their larvae from mid to late spring (late October-November) after an incubation period of 3-5 months, inversely dependent on temperature (Heydorn, 1969; Newman & Pollock, 1981; MacDiarmid, 1989a). Individuals transported to Sanriku, in northern Japan, and maintained at local ambient light cycles and temperatures of 10-20°C rapidly underwent a phase shift of about 6 months. Peak moulting of female J . edwardsii occurred in August-September, especially in the first year of captivity, while females bearing freshly spawned eggs were found from October through to April (autumn to spring), with hatching occurring from December to June (winter/late spring) (Kittaka, 1987). Captive Australian J. edwardsii spawned in July and hatched their larvae in September (Kittaka, 1987) while J. lalandii spawned their eggs in December and May and larvae hatched in May and August (Kittaka, 1988). For New Zealand-derived J. edwardsii the period from moulting to spawning was 19-38 days (average 24) and eggs were incubated for 51-81 days (average 58.5). Moult-spawn and incubation periods were 15-24 days

Breeding

501

and 59-64 days, respectively, for Australian J. edwardsii and 22-25 days and 37-124 days for J. lalandii (Kittaka, 1987, 1988). Jasus edwardsii and J . lalandii are closely related (George & Kensler, 1970; Ovenden er al., 1997). This was confirmed in hybridization experiments where female J. lalandii which moulted in the period late October to early January mated with Australian sourced male J. edwardsii between December and mid-January. Two of five females were observed to carry fertilized eggs, although these were subsequently lost before hatching, probably because of a water quality problem. Jasus verreauxi

In New Zealand mature females mate in October-November and carry eggs until they hatch in December-January (Booth, 1984). Egg-bearing females obtained from the wild hatched small larvae with poor survival (Moss, unpubl. data). In Japan this species had a very regular reproductive cycle approximately 6 months out of phase with the wild populations in New Zealand (Fig. 27.4). Females moulted in December

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502 Spiny Lobsters: Fisheries and Culture

and January, except in their first year of captivity when some also moulted in July. Males moulted from October to January. Females with early stage eggs were found in April and May, while hatching occurred in July and August. At maturity captive females changed colour from brownish green to pale pink. Although males become rather aggressive towards one another during the mating season several males were cultured with females. Panulirus homarus

Breeding experiments on this species have been carried out in two localities. In South Africa, Berry (1970) observed the reproductive activity of 30 lobsters in a large (4500 litre) naturalistic aquarium. One male dominated matings in two consecutive breeding seasons. Although it was only the third largest male, it displayed very high levels of aggression towards the other 14 males in the tank and prevented them from proceeding beyond the very earliest stages of courtship with receptive females. Seventeen matings were recorded and all resulted in a fertilized brood of eggs. In India, juvenile P . homarus have been successfully raised to maturity and bred in large, 10 000-litre tanks at 26-30°C and on a diet of bivalves and fish (Radhakrishnan, 1977). It took 14 months for juveniles of 35 mm CL to reach sexual maturity at 58 mm CL and start to reproduce. The effects of eyestalk ablation on reproduction have been investigated in this species (Radhakrishnan & Vijayakumaran, 1984). Removal of the eyestalks accelerated gonadal growth in both males and females, but also had negative effects on reproductive behaviour. Ablated males deposited spermatophores indiscriminately on other males and immature females. Ablated females would sometimes moult while brooding a clutch of eggs, resulting in its loss. Panulirus argus

In the wild this northern warm-water species reproduces seasonally from late winter through to early autumn, although this season is much longer in equatorial regions (Lyons et al., 1981). In the laboratory long daylengths and warmer temperatures enhance courtship, spawning frequencies and female gonadal development, but not male gonadal development (Lipcius & Herrnkind, 1985, 1987). Conversely, reproductive activity can be suspended in lobsters held at short daylengths and low temperatures (Lipcius & Hermkind, 1987), thereby allowing breeding to take place under controlled conditions at any time of year. Reproduction and moulting are size dependent with the largest mature individuals mating early in the reproductive season and the smallest moulting, while the intermediate sized ones either mate or moult before mating (Lipcius, 1985; Lipcius & Herrnkind, 1987). Mating activity peaks near crepuscular periods and is usually initiated by large dominant males, although females will approach males if they have not copulated and are near the time of spawning (Lipcius & Herrnkind, 1985).

Breeding

503

Panulirus cygnus

In the wild, P. cygnus mate in the austral spring and early summer (October to early January) and incubate eggs for about 30 days at 23°C (Chittleborough, 1976). About two-thirds of the mature female population have two successive clutches per season, with the probability of this increasing with female size (Chubb, 1994). In the laboratory under 12:12 light/dark cycles, mating occurs as early as June, with the first broods starting incubation by early August and the last broods hatching in February (Chittleborough, 1976). When wild mature females are first brought into captivity about half undergo only a single moult between breeding seasons, while the remainder moults twice with a loss of ovigerous setae on the pleopods after the first moult, regaining them on the second. After a year in captivity all females undergo the two-moult cycle, perhaps in response to improved nutritional state (Chittleborough, 1976). In captivity, juveniles can be raised from pueruli to maturity in about 5 years and bred repetitively at 25°C with up to three broods between successive moults and up to six broods per year (Chittleborough, 1974, 1976).

27.4

Conclusions

Spiny lobsters are physically robust and have many behavioural features which make them amenable to captive breeding and may compensate for difficulties in larval culture (Chapters 28 and 29). Breeding has been achieved for all species examined under laboratory conditions. Adults are easily transported live around the world if necessary. Brood stock is able to be conditioned on live or frozen diets and in a wide variety of tanks as long as water quality is high. Moulting and mating schedules are readily controlled by changes in daylength and water temperature to yield year-round production of larvae if required. Although it is clear from an increasing number of field and laboratory observations that mating behaviour, egg extrusion, fertilization, egg bearing and hatching are fundamentally the same amongst spiny lobster species, female Jams spp. are particularly vulnerable to mate availability and need to be managed more carefully than female Panulirus spp. Males also need careful management to ensure that they have time to recover sperm supplies after repeated matings. Observation of the reproductive behaviour of spiny lobsters in the wild has been important in clarifying many aspects of breeding and has suggested other areas where more laboratory investigation is necessary. More detailed observations of reproduction in wild populations will, without doubt, enhance our knowledge of reproductive behaviour and assist in the production of ‘seed’ for aquaculture.

References Aiken, D.E. & Waddy, S.L. (1980) Reproductive biology. In The Biology andktanagernent of Lobsters, Vol. 1 (Ed. by J.S.Cobb & B.F. Phillips), pp. 215-76. Academic Press, New York, USA.

504 Spiny Lobsters: Fisheries and Culture Annala, J.H. & Bycroft, B.L. (1987) Fecundity of the New Zealand red rock lobster, Jams edwardsii. N.Z. J . Mar. Freshwat. Res., 21, 591-7. Ansell, A.D. & Robb, L. (1977) The spiny lobster Palinurus elephas in Scottish waters. Mar. Biol., 43, 63-70. Arana, P., Dupre, E. & Gaete, V. (1985) Ciclo reproductivo, talla de primea madurez sexual y fecundidad de la langosta de Juan Fernandez (Jasusfrontalis). In Investigaciones marinas en e Archipelago de Juan Fernandez (Ed. by P. Arana), pp. 187-211. Escuela de Ciencias del Mar, Universidad Catolica de Valparaiso, Valparaiso, Chile. Atema, J. & Cobb, J.S. (1980) Social behaviour. In The Biology and Management of Lobsters, Vol. 1 (Ed. by J.S. Cobb & B.F. Phillips), pp. 409-50. Academic Press, New York, USA. Beard, T.W & McGregor, D. (1991) Storage and Care of Lobsters. MAFF, Directorate of Fisheries Research, Laboratory Leaflet No. 66, 33 pp. Berry, P.F. (1970) Mating behaviour, oviposition and fertilization in the spiny lobster Panulirus homarus (Linnaeus). Oceanogr. Res. Inst. (Durban) Invest. Rep., 24, 1-16. Berry, P.F. (1971) The spiny lobsters (Palinuridae) of the east coast of southern Africa: distribution and ecological notes. Oceanogr. Res. Inst. (Durban) Invest. Rep., 21, 1-23. Berry, P.F. & Heydorn, A.E.F. (1970) A comparison of the spermatophoric masses and mechanisms of fertilisation in southern African spiny lobsters (Palinuridae). Oceanogr. Res. Inst. (Durban), Invest. Rep., 25, 1-18. Bonde, C. von (1936) The reproduction embryology and metamorphosis of the Cape crawfish (Jasus lalandii) (Milne Edwards) Ortmann. Invest. Rep. Fish. Mar. Biol. S u n . Div. Un. S. Afr., 6, 1-25. Booth, J.D. (1984) Size at onset of breeding in female Jams verreauxi (Decapoda: Palinuridae) in New Zealand. N.Z. J. Mar. Freshwat. Res., 18, 15949. Briones-Fourzin, P. & Lozano-Alvarez, E.(1992) Aspects of reproduction of P . inflatus (Bouvier) and P.gracilis Streets (Decapoda: Palinuridae) from the Pacific coast of Mexico. J. Crust. Biol., 12,41-50. Chittleborough, R.G. (1974) Western rock lobsters raised to maturity. Aust. J. Mar. Freshwat. Rex, 25, 221-7. Chittleborough, R.G. (1976) Breeding of Panulirus longipes cygnus George under natural and controlled conditions. Aust. J. Mar. Freshwat. Res., 21, 499-516. Chubb, C.F. (1994) Reproductive biology: issues for management. In Spiny Lobster Management: Current Situation and Perspectives (Ed. by B.F. Phillips, J.S. Cobb & J. Kittaka), pp. 181-212. Blackwell Scientific Publications, Oxford, UK. Crear, B.J. & Forteath, G.N.R. (1998) A physiological investigation into methods of improving post-capture survival of both the southern rock lobster, Jasus edwardsii, and the western rock lobster, Panulirus argus. Fisheries Research and Development Corporation, Final Report for Project 94/134.03, University of Tasmania, 165 pp. Creaser, E.P. (1950) Repetition of egg laying and number of eggs of the Bermuda spiny lobster. Proc. Gulf Carib. Fish. Inst., 2, 30-1. Deguchi, Y. (1988) Spiny lobsters Part 11, Section 4. In Seed Production of Decapod Crustaceans (Ed. by R. Hirano), pp. 64-76. Koseisha-Koseikaku, Tokyo, Japan. Deguchi Y., Sugita H. & Kamemoto F. (1991) Spawning control of the Japanese spiny lobster. Mem. Qld Mus., 31, 449. Evans, L.H. & Brock, J.A. (1994) Diseases of spiny lobsters. In Spiny Lobster Management: Current Situation and Perspectives (Ed.by B.F. Phillips, J.S. Cobb & J. Kittaka), pp. 461-72. Blackwell Scientific Publications, Oxford, UK. Fonteles-Filho, A.A. & Ivo, C.T.C. (1980) Migratory Behaviour of the spiny lobster Panulirus argus (Latreille), off Ceara State, Brazil. Arq. Cien. Mar., 20, 25-32. George, R.W. & Kensler, C.B. (1970) Recognition of marine spiny lobsters of the Jams lalandii group (Crustacea: Decapoda: Palinuridae) N.Z. J. Mar. Freshwat. Res., 4, 292-31 1.

Breeding

505

Gibson, I.D. & Frusher, S. (1997) How large a harem can one rock lobster handle? Lobster Newslett., 10(1), 6-7. Gregory, D.R., Labisky, R.F. & Coombs, C.L. (1982) Reproductive dynamics of the spiny lobster Panulirus argus in south Florida. Trans. Am. Fish. SOC.,111, 575-84. Herrnkind, W.F. (1980) Spiny lobsters: patterns of movement. In The Biology and Management of Lobsters, Vol. 1 (Ed. by J.S. Cobb & B.F. Phillips), pp. 349407. Academic Press, New York, USA. Heydorn, A.E.F. (1969) The rock lobster of the South African west coast Jams lalandii (H. MilneEdwards) 2. Population studies, behaviour, reproduction, moulting, growth and migration. Invest. Rep. Div. Sea Fish. S. Afr., 71, 1-52. Ino, S . (1950) Observations on the spawning cycle of Ise-ebi (Panulirusjaponicus v. Siebold). Nippon Suisan Gakkaishi, 15, 725-7. Juinio, M.A.R. (1987) Some aspects of the reproduction of Panulirus penicillatus (Decapoda: Palinuridae). Bull. Mar. Sci., 41, 242-52. Kanciruk, P.(1980) Ecology ofjuvenile and adult Palinuridae (spiny lobsters). In The Biology and Management ofLobsters, Vol. 2 (Ed. by J.S. Cobb & B.F. Phillips), pp. 59-96. Academic Press, New York, USA. Kanciruk, P. & Herrnkind, W.F. (1976) Autumnal reproduction in Panulirus argus at Bimini, Bahamas. Bull. Mar. Sci., 26, 417-32. Kelly, S., MacDiarmid, A.B. & Babcock, R.C. (1999) Characteristics of spiny lobster, Jasus edwardsii, aggregations in exposed reef and sandy areas. Mar. Freshwat. Res., SO, 409-16. Kensler, C.B. (1967) Fecundity in the marine spiny lobster Jasus verreauxi (H. Milne Edwards) (Crustacea: Decapoda: Palinuridae). N.Z. J. Mar. Freshwat. Res., 1, 143-55. Kittaka, J. (1987) Ecological survey of rock lobster Jasus in the southern hemisphere. Ecology and distribution of Jasus along the coast of Australia and New Zealand. Report to the Ministry of Education, Culture and Science, pp. 1-232. Kittaka, J. (1988) Culture of the palinurid Jasus lalandii from egg stage to puerulus. Nippon Suisan Gakkaishi, 54, 87-93. Kittaka, J. & Ikegami, E. (1988) Culture of the palinurid Palinurus elephas from egg stage to puerulus. Nippon Suisan Gakkaishi, 54, 4 13-1 7. Kittaka, J. & Kimura, K. (1989) Culture of the Japanese spiny lobster Panulirusjaponicus from egg to juvenile stage. Nippon Suisan Gakkaishi, 54, 1149-54. Kittaka, J., Iwai, M. & Yoshimura, M. (1988) Culture of a hybrid of spiny lobster genus Jasus from egg stage to puerulus. Nippon Suisan Gakkaishi, 54,413-17. Lipcius, R.N. (1985) Size dependent reproduction and moulting in spiny lobsters and other longlived decapods. In Crustacean Issues, Vol. 3, Factors in Adult Growth (Ed. by W.A. Wenner), pp. 12948. Balkema Press, Rotterdam, The Netherlands. Lipcius, R.N. & Herrnkind, W.F. (1985) Photoperiodic regulation and daily timing of spiny lobster mating behaviour. J. Exp. Mar. Biol. Ecol., 89, 191-204. Lipcius, R.N. & Herrnkind, W.F. (1987) Control and coordination of reproduction in the spiny lobster Panulirus argus. Mar. Biol., 96, 207-14. Lipcius, R.N., Edwards, M.L., Herrnkind, W.F. & Waterman, S.A. (1983) In situ mating behaviour of the spiny lobster Panulirus argus. J. Crust. Biol., 3, 217-22. Lyle,W.G. & MacDonald, C.D. (1983) Molt stage determination in the Hawaiian spiny lobster Panulirus marginatus. J. Crust. Biol., 3, 208-16. Lyons, W.G., Barber D.G., Foster, S.M., Kennedy, F.S. & Milano, G.R. (1981) The spiny lobster of the middle and upper Florida Keys: population structure, seasonal dynamics and reproduction. FI. Mar. Res. Publ., 38, 1 4 5 . MacDiarmid, A.B. (1985) Sunrise release of larvae from the palinurid rock lobster Jams edwardsii. Mar. Ecol. Prog. Ser., 21, 313-15.

506 Spiny Lobsters: Fisheries and Culture MacDiarmid, A.B. (1987) The ecology of Jasus edwardsii (Hutton) (Crustacea: Palinuridae). Ph.D . thesis, University of Auckland, New Zealand. MacDiarmid, A.B. (1988) Experimental confirmation of external fertilisation in the southern temperate rock lobster Jasus edwardsii (Hutton) (Decapoda: Palinuridae). J. Exp. Mar. Biol. Eco~.,120, 277-85. MacDiarmid, A.B. (1989a) Moulting and reproduction of the spiny lobster Jasus edwardsii (Decapoda: Palinuridae) in northern New Zealand. Mar. Biol., 103, 303-10. MacDiarmid, A.B. (1989b) Size at onset of maturity and size dependent reproductive output of female and male spiny lobsters Jams edwardsii in northern New Zealand. J. Exp. Mar. Biol. Ecol., 127, 22943. MacDiarmid, A.B. (1991) Seasonal changes in depth distribution, sex ratio and size frequency of spiny lobster Jusus edwardsii on a coastal reef in northern New Zealand. Mar. Ecol. Prog. Ser., 70, 12941. MacDiarmid, A.B. (1994) Cohabitation in the spiny lobster Jasus edwardsii. Crusfaceana, 66, 341-55. MacDiarmid, A.B. & Butler, M.J. (1999). Sperm economy and limitation in spiny lobsters. Behav. Ecol. Sociobiol., 46, 14-24. MacDonald, C.D. (1982) Catch composition and reproduction of the spiny lobster Panulirus versicolor at Palau. Trans. Am. Fish. Soc., 111, 694-9. MacFarlane, J.W. & Moore, R. (1986) Reproduction of the ornate rock lobster Panulirus ornatus (Fabricius) in Papua New Guinea. Aust. J. Mar. Freshwater Res. 37, 5 5 4 5 . McKoy, J.L. (1979) Mating behaviour and egg laying in captive rock lobster, Jasus edwardsii (Crustacea: Decapoda: Palinuridae). N.Z. J. Mar. Freshwat. Res., 13, 407-13. McKoy, J.L. & Leachman, A. (1982) Aggregations of ovigerous female rock lobsters Jasus edwardsii (Decapoda: Palinuridae). N.Z. J. Mar. Freshwat. Res., 16, 141-6. Matthews, D.C. (1951) The origin, development and nature of the spermatophoric mass of the spiny lobster, Panulirus penicillatus (Oliver). Pac. Sci., 5, 359-71. Mota Alves, M.I. & Paiva, M.P. (1976) Freqencia de acaslamentos em lagostas do egenero Panulirus White (Decapoda, Palinuridae). Arq. Cien. Mar., 16, 61-3. Nagai, H. (1956) Copulation and spawning of the Japanese spiny lobster. Suisan Zoshoku, 4,9-11. Nair, R.V., Soundararajan, R. & Nandakuma, G. (1981) Observations on growth and moulting of spiny lobsters Panulirus homarus (Linnaeus), P . ornatus (Fabricius) and P . penicillatus (Olivier) in captivity. Ind. J . Fish., 28, 25-35. Newman, G.G. & Pollock, D.E. (1981) Biology and migration of rock lobster Jasus lalandii and their effect on availability at Elands Bay, South Africa. Invest. Rep. Div. Sea Fish. S. Afr., 94, 1-24. Nonaka, M. (1988) Spiny lobster, Part I, Section 2. In Seed Production of Decapod Crustaceans (Ed. by R. Hirano), pp. 28-38. Koseisha Koseikaku, Tokyo, Japan. Oshima, Y . (1942) Ecological observations of the Japanese spiny lobster. Suisan Gakkaiho, 8,231-8. Ovenden, J.R., Booth J.D. & Smolenski, A.J. (1997) Mitochondria1 DNA phylogeny of red and green rock lobsters (genus Jasus). Mar. Freshwat. Res., 48, 11314. Paterson, N.F. (1969a) Behaviour of captive cape rock lobsters, Jaws lalandii (H. Milne Edwards). Annul. S. Afr. Mus., 52, 22544. Paterson, N.F. (1969b) Fertilization in the Cape rock lobster, Jasus lalandii (H. Milne Edwards). S. Afr. J. Sci., 65, 163. Phillips, B.F., Cobb J.S. & George, R.W. (1980) General biology. In The Biology and Management of Lobsters, Vol. 1 (Ed. by J.S. Cobb & B.F. Phillips), pp. 1-82. Academic Press, New York, USA. Radha, T. & Subramoniam, T. (1985) Origin and nature of spermatophoric mass of the spiny lobster Panulirus homarus. Mar. Biol., 86, 13-19.

Breeding

501

Radhakrishnan, E.V. (1977) Breeding of laboratory reared spiny lobster Panulirus homarus (Linnaeus) under controlled conditions. Ind. J. Fish., 24, 269-70. Radhakrishnan, E,V. & Vijayakumaran, M. (1984). Effect of eyestalk ablation in the spiny lobster Panulirus homarus (Linnaeus): 3 . On gonadal maturity. Ind. J. Fish., 31, 209-16. Sastry, A.N. (1983) Ecological aspects of reproduction. In The Siorogy of Crustacea, Vol. 8, Environmental Adaptations (Ed. by F.J. Vernberg & W.B. Vernberg). Academic Press, New York, USA. Shaklee, J.B. (1983) Mannosephosphate isomerase in the Hawaiian spiny lobster Panulirus marginatus: a polymorphic, sex linked locus useful in investigating embryonic and larval sex ratios. Mar. Biol., 73, 193-201. Shields, J.D. & Kuris, A.M. (1989) Carcinonemertes wickhami n. sp. (Nemertea), a symbiotic egg predator from the spiny lobster Panulirus interruptus in southern California, with remarks on symbiont-host adaptations. Fish. Bull. US.,88, 279-87. Shiino, S. (1950) Studies on the embryonic development of Panulirus japonicus (von Siebold). J . Fac. Fish. Univ. Mie., 1, 1-168. Silberbauer, B.I. (1971) The biology of the South African rock lobster Jasus lalandii (H. Milne Edwards) 1. Development. S. Afr. Div.Sea Fish. Invest. Rep., 92, 1-70. Stead, D.H. (1973) Rock lobster salinity tolerance. NZ Fisheries Technical Report, No. 122, 10 pp. Street, R.J. (1969) The New Zealand crayfish Jasus edwardsii (Hutton). Fish. Tech. Rep. N . Z . Mar. Dep., 30, 1-24. Tong, L.J., Moss, G.A., Pickering, T.D. & Paewai, M.M. (2000) Temperature effects on embryo and early larval development of the spiny lobster Jasus edwardsii, and a description of a method to predict larval hatch times. Mar. Freshwat. Res., 51, 243-8.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 28

Culture of Larval Spiny Lobsters J. KITTAKA Research Institutefor Marine Biological Science, Research Institutesfor Science and Technology, The Science University of Tokyo, Nernuro City. Fisheries Research Institute. Hokkaido. 087-0166,Japan 28.1

Introduction

Spiny lobsters are a valuable marine resource in many countries. The world-wide supply is limited in relation to demand. However, an increase in production in the near future is unlikely owing to the intense fishing pressure, which takes a large proportion of the available stocks, and the lack of appropriate technology for aquaculture. The major impediment for aquaculture is the supply of cultured larvae. Once developed, larval culture will be able to supply large numbers of juveniles to growout systems. The phyllosoma larva of spiny lobsters has a flat and leaf-like body, which at hatching is about 1.5-2.0 mm long. Phyllosomas grow continuously by a series of moults until they reach the final instar at a length of about 30 mm. The final-stage phyllosomas metamorphose into the puerulus stage, which is the transitional stage from the pelagic phyllosoma to the benthic juvenile. It is estimated that the period from the first instar to metamorphosis into the puerulus stage of Panulirusjaponicus is about 1 year, because settlement of the pueruli is observed in the following summer after hatching. Phyllosoma larval culture experiments have been carried out for more than 50 years in Japan (Hattori & Oishi, 1899; Oshima, 1936; Nonaka et al., 1958; Saisho, 1962, 1966a, b; Inoue & Nonaka, 1963; Inoue, 1965, 1978, 1981; Nishimura, 1983; Nishimura & Kawai, 1984; Nishimura & Kamiya, 1985, 1986; Kamiya et al., 1986). The first published record of successful larval culture was of phyllosomas of P . japonicus, which moulted to stage I1 when fed Artemia nauplius (Nonaka et al., 1958). The period of the phyllosoma culture gradually extended to 178 days (Saisho, 1966b) and 253 days (Inoue, 1978). However, complete larval development was not achieved until it was demonstrated for Jasus lalandii by Kittaka (1988). In addition, culture has been achieved of a hybrid between Jasus novaehollandiae and Jasus edwardsii (Kittaka et al., 1988), and of the species Palinurus elephas (Kittaka & Ikegami, 1988), P . japonicus (Yamakawa et al., 1989; Kittaka & Kimura, 1989; Fushimi et al., Japan Sea Farming Association, Minami-Izu, Shizuoka Pref., pers. comm.; Tsutsumi et al., Tazaki Pearl Co., Ltd., Hiwasa, Tokushima Pref., pers. comm.; Sekine, 1996) and Jasus verreauxi (Kittaka et al., 1997). For J. edwardsii, complete larval development was shown in Japan (Kittaka, Ono, Onoda, Webber & Booth, unpubl.) and New Zealand (Booth, 1996). Research has also been conducted on culturing spiny lobsters from the egg to the puerulus stage in several other species including Panulirus argus in Florida (Moe, 508

Culture of Larval Spiny Lobsters

509

1991), J . lalundii in South Africa (Silberbauer, 1971), Panulirus interruptus in California (Dexter, 1972) and Panulirus homarus in India (Radhakrishnan & Vijayakumaran, 1995). Archer & Nickell (1997) reviewed the studies on P . elephas. Because of the difficulty in growing phyllosomas from hatching to metamorphosis little has been known about the early life history of spiny lobsters. Recent progress in complete development from phyllosomas to puerulus has revealed much about the ecology and behaviour of these unique marine life stages (Kittaka, 1990). Phyllosoma culture was reviewed, based mainly on the experiments carried out in Japan, by Kittaka (1994a, b, 1997a, b). Success of culture depends on the culture method by which environmental and nutritional requirements for the phyllosomas can be satisfied. These requirements link each other; therefore, research has to be carried out with deep insight into water quality and foods in the phyllosoma culture. In this chapter, recent developments in phyllosoma culture are reviewed, with particular emphasis on foods and feeding. The feasibility of large-scale larval culture of spiny lobster will also be discussed. Details of the environmental requirements for phyllosomas are presented in Chapter 29. 28.2

Selection of species

Spiny lobsters used for culture experiments were initially limited to local species. In Japan, enormous efforts were concentrated on P . japonicus but with limited success. Biological information on reproductive characteristics indicates that the species is highly adapted to Japanese waters, suggesting that P . japonicus may be a difficult species to culture. Recent progress in methods of transportation has made it possible to ship adults of any species to any locality. Thus, culture experiments need not be limited to a native species, and much effort has been devoted to several exotic species (Kittaka, 1981, 1984, 1987b). As the ambient seawater temperatures at Sanriku (the experimental site during the period from 1982 to 1995) ranged between 6 and 2WC, cool temperate species of the genera Jams and Palinurus were selected (Kittaka, 1981, 1984, 1987b). For some of these species, larval culture may be easier than that for the subtropical P . japonicus. Surveys of populations and habitats of P . elephas in Ireland and France in 1979 (Kittaka, 1981), J . lulandii in South Africa in 1982 (Kittaka, 1984), and J . edwardsii and J. verreauxi in New Zealand and Australia in 1985 (Kittaka, 1987b) helped to elucidate the optimal environmental conditions for these species. Several mature females and males of each species were airfreighted from these countries to Sanriku, Japan, for breeding experiments (Kittaka & MacDiarmid , 1994) (Table 28.1). 28.3

Culture system

Phyllosomas can be cultured in still, running or recirculating water. Phyllosomas are not cannibalistic, therefore, they can be cultured communally or individually.

5 10 Spiny Lobsters: Fisheries and Culture Table 28.1 Species of spiny lobster that have been cultured through their complete larval development at Sanriku, Japan

Species

Origin

South Africa Tasmania and New Zealand Jusus edwardsii North New Zealand Jasus verreauxi North New Zealand Palinurus elephas Ireland and France Jasus lalandii Jasus hybrid

Panulirus japonicus

Japan

No. of Reference Date of metamorphosis puerulus 2 Jun 1987

1

31 Jul 1987

2

18 Oct 1990 7Feb 1991 16 Jul 1987

16 168 1

22 Jun 1988

2

Kittaka (1988) Kittaka et al. (1 988) Kittaka et al. (unpubl.) Kittaka et al. (1997) Kittaka & Ikegami (1988) Kittaka & Kimura ( 1989)

For J. edwardsii, a single puerulus was cultured in New Zealand (Booth, 1996; Tong, pers. comm.). Pueruli of P. japonicus were cultured at Mie Prefectural Fisheries Technology Center (Yamakawa er al., 1989), Tazaki Pearl Co. Ltd (Tsutsumi, pers. comm.) and Japan Marine Farming Association (Nonaka, 1996; Sekine, 1996).

Usually, still water has been used for small numbers of larvae and running water for mass culture. However, because of the planktonic life of phyllosomas, scale-up of the still-water culture system would not be suitable even if the culture water were changed daily. The larvae must be kept suspended, because sinking to the bottom is fatal. A circular tank is the most effective to create a circular current with varying velocities for culture with running water. Inoue (1978) designed a circular tank with water supplied through tiny holes in the wall and the bottom to create currents of 2-4 cm/s. A single phyllosoma of P . japonicus was cultured to the final stage (Inoue, 1978). Better results were obtained using tanks with an upwelling system, which were modified from a plankton-kriesel designed for clawed lobster larval culture by Hughes et al. (1974) (Kittaka & Yawata, unpubl. data). Tanks of 16, 30 and 100 litres were used for rearing the phyllosomas. The 16-litre tanks with concave bottoms are made of glass, whereas the 30-litre and 100-litre tanks with flat bottoms are made of transparent plastic to permit convenient viewing of the phyllosomas. At present, those with concave bottoms are manufactured commercially. The 30-litre tanks are used for culture of small numbers of larvae, particularly for the advanced stages. The 100-litre tanks are used for culture of the first instar in large numbers. The velocity of the current is controlled by adjusting the water supply to the tank. Usually, it is maintained at about 5 cm/s on the bottom and about 3 cm/s on the surface. Screens fitted to the drainpipe have a mesh of 100 holes/2.5 cm, which prevents the escape of Artemia nauplii, the food at the initial stage. The mesh of the screen ranges from 100 to 25/2.5 cm, and the screen is replaced with coarser mesh as the phyllosomas grow. The screens are replaced every 2-4 weeks due to fouling and choking of the mesh. Dead phyllosomas and food

Culture of Larval Spiny Lobsters

51 1

remains are removed daily. Such complicated procedures may be a problem for large-scale culture systems in the future. Illingworth et al. (1997) designed an upwelling tank with ports, which allow the transfer of phyllosomas during the cleaning of tanks. The first breakthrough in phyllosoma culture was achieved by feeding mussels, Mytilus edulis, at Sanriku (Kittaka, 1988). The phyllosoma culture tanks (capacity 30-100 litres) were combined with the microalgae culture tank (capacity 300500 litres), and the microalgae recirculated in the culture system as shown in Fig. 28.1. The microalgae are considered to play a role in water quality control and microflora control (Kittaka, 1994a; Igarashi & Kittaka, 2000). The microalga, Nannochloropsis oculata has been used because of its long-term growth (referred to as the microalga method). As an alternative to N. oculata, Tetraselmis sp. and marine diatoms Phaeodactylum sp., Nitzschia sp., Chaetoceros sp. and Thalassiosira sp. (Kittaka, 1994a; Kittaka & Abrunhosa, 1997) were tested. The following nutrients were added in algal cultures: ammonium sulphate at 100 ppm, calcium dihydrogen phosphate at Sfreen

Water supply-

Culture lamp Air supply

i

1I

l

i

Algal culture tank

m

.

Fig. 28.1 Tank for the culture of the phyllosoma larvae of spiny lobsters. A tank using the microalga method is shown. The culture system is modified to a tank using the recirculatefilter method after installation of a coral sand layer on a double-bottomed structure in the ‘algal culture’ tank. For the latter method, microalgae are not cultured and the culture lamp is turned off.

5 12 Spiny Lobsters: Fisheries and Culture

10 ppm, urea at 30 ppm and Clewat-32 (EDTA metals complex salt) at 4 ppm for N . oculata and Tetraselmis sp. culture (Okauchi, 1987) and potassium nitrate at 200 ppm, sodium phosphate dibasic 3.6 ppm, sodium metasilicate enneahydrate at 2.8 ppm, sodium molybdate dihydrate at 0.13 ppm, iron chloride hexahydrate at 0.39 ppm, vitamin BI2at 0.002 ppm, sodium bicarbonate at 60 ppm, boric acid at 3.4 ppm and EDTA-2Na at 6 ppm for diatom culture (Shigueno, 1992). In the microalga method, particular caution is necessary concerning the possible effect of the residue of nutrients on phyllosomas. Another method for water quality control is to use a recirculate-filter system. Saisho (1966b) cultured phyllosomas of P . japonicus in a flat-bottomed aquarium with recirculating water through a sand filter for about 90 days with 12 moults. The result was better than those obtained in his still-water culture. Recently, in Nemuro, a new experimental site in north Japan, phyllosoma culture tanks (capacity 100 litres) were combined with a coral sand filter tank (capacity 300-500 litres; capacity of coral sand 90-150 litres; referred to as the recirculate-filter method) (Kittaka, Kudo & Onoda, unpubl. data). Ammonium-N was never detectable in the culture water of either method. Total numbers of bacteria were about 100 times higher in the microalga method than in the recirculate-filter method (Igarashi & Kittaka, 2000). Phyllosoma culture results were compared between both methods for J . verreauxi. The phyllosomas metamorphosed into pueruli with a survival rate of 12.6% for 189-273 days in 1991 using the microalga method (Kittaka et al., 1997). A comparable result was achieved by the recirculate-filter method with a survival rate of 5.3% for 189-295 days in 1998 (Kittaka et al., unpubl. data). The culture water was changed at intervals of about 2 weeks for the microalga method and about 1 month for the recirculate-filter method.

28.4

Food and feeding

The most important factor in phyllosoma culture is considered to be food and feeding to provide adequate nutrition for the larvae. A wide variety of foods has been tried for different larval instars of both spiny and slipper lobsters by many researchers (Tables 28.2 and 28.3). However, only a few food types have shown promise.

28.4.1

Artemia salina

Artemia nauplii have been the most common food used for phyllosomas, particularly for the early instars, because of their size, movements and nutritional value (Nonaka et al., 1958; Inoue and Nonaka, 1963; Saisho, 1962, 1966a, b; Inoue, 1978, 1981). The first-instar phyllosomas moulted into the second stage within 10 days when fed exclusively with Artemia nauplii, indicating the high food value of Artemia at the first stage (Saisho, 1966a, b; Inoue, 1978). As the phyllosomas grew, a preference for

Culture of Larval Spiny Lobsters

513

Table 28.2 Food used for phyllosomas of spiny lobsters (Panulirus spp.) Food species Panulirus japonicus (instars 1-12) Artemia salina (early nauplii) Echinometra marhaei (gonad) Palaemon pacificus (minced flesh) Daphnia pulex (dried matter) Acartia (alive) Moina macrocopa (alive) Sagitta (alive) Olizias latipes (alive) Lebiztes reticulatus (alive)

Fish larvae"

Food value

Reference

+ + (for instar <1)

Saisho (1966a, b) Saisho (1966a, b) Saisho (1966a, b) Saisho (1966a, b) Saisho (1966a, b) Saisho (1966a, b) Saisho (1966a, b) Saisho (1966a, b) Saisho (1966a, b) Inoue (1978, 1981)

+ (for instar 2) + (for instar 3) + (for instar 3)

+ (for instar 3)

+ (for instar 3) + (for instar 5 ) +

(for instar 5 )

+ (for instar 7) + (for instar 210)

Panulirus argus (instars 1-3)

Angel fish (alive) Mangrove snapper (alive) Dolphinb (flesh, - 1 mm) Dolphinb (boiled) Artemia (juveniles, 7 days old) Conch (fresh, grated) Jewelfishc (larvae) Coral banded shrimpd (larvae, alive) Jellyfish (fresh, strips) Panulirus interruptus (instar 1)

+ + (7-10 days)

++

+ (21-27

days, instar 3)

-

+

+ (6-7 days, instar 2)

+ + +

Tubijkx Mytilus (gonad)

- (insufficient nutrition)

Sea urchine (gonad) Chaetognaths Ctenophores Fish larvae Artemia nauplii Artemia juveniles

- (insufficient nutrition)

- (insufficient nutrition)

+ (good) + (good) + (good)

+ + (as major food)

++

Moe (1991) Moe (1991) Moe (1991) Moe (1991) Moe (1991) Moe (1991) Moe (1991) Moe (1991) Moe (1991) Dexter (1972) Dexter (1 972) Dexter (1972) Dexter ( 1972) Dexter (1972) Dexter (1972) Dexter (1972) Dexter (1972)

aMarbled sole (Limanda yokohamae), stone flounder (Kareius bicoloratus), finespotted flounder (Pleuronichthys cornutus), marbled rockfish (Sebastiscus marmoratus), yellowfin goby (Acanthogobius flavimanus), pinkgray goby (Amblychaeturichthys hexanema), brown goby (Bathygobius fuscus), whitebait goby (Favonigobius gymnauchen), silver whiting (Sillago japonica), largescale blackfish (Girella punctata), red sea bream snapper (Pagrus major), black porgy (Acanthopagrus schlegeli), rock porgy (Oplegnathus fasciatus, Parapristipoma trilineatum), Japanese seaperch (Lateolabrax japonicus), chub mackerel (Scomber japonicus), Japanese anchovy (Engraulis japonica), Ayu (Plecoglossus altivelis). bCoryphaena hippurus. 'Microsapathodon chrysurus. dStenopus hispidus. eCassiopea sp. Source: Kittaka (199713). Food value: + + , excellent; + , usable; -, poor.

5 14 Spiny Lobsters: Fisheries and Culture Table 28.3 Food given to phyllosomas of spiny lobsters (Jasus sp.) and slipper lobsters (Ibacus spp.)

Food species

Food value

Jasus edwardsii (instar 1) Artemia (nauplii) - (not eaten) Obelia (medusae) - (not eaten) Calanoid copepods - (not eaten) Crab (zoeas) - (not eaten) Trochophore/Velliger - (not eaten) Mytilus muscle - (not eaten) Tadpole (Ascidian larvae) - (not eaten) Capitellid polychaete + (purposefully eaten) Ibacus ciliatus and I . hovemdentatus (instars < 1) Sebastiscus marmoratus + (moult to instars 3, 4) (larvae, 3.5 mm) Sebastes innermis + (moult to instars 3, 4) (larvae, 5.0 mm) Sebastes pachycephalus + (moult to instars 3, 4) (larvae 7.0 mm) Tridentiger trigonocephalus + (moult to instar 3) (larvae 3.0 mm) Tridentiger obscurus + (moult to instar 3) (larvae 3.0 mm) Artemia (nauplii) - (not eaten) Penagrellus silusiae (Nematoda) - (not eaten) Artemia (nauplii) + (complete development) Tapes philippinarum (flesh) + (complete development)

Source: Kittaka (1997). Food value: + +, excellent;

Reference Batham (1967) Batham (1967) Batham (1967) Batham (1967) Batham (1967) Batham (1967) Batham (1967) Batham (1967) Doutsu et al. (1966) Doutsu et al. (1966) Doutsu et al. (1966) Doutsu et al. (1966) Doutsu et al. (1966) Doutsu et al. (1966) Doutsu et al. (1966) Takahashi & Saisho (1978) Takahashi & Saisho (1978)

+, usable; -, poor.

large-sized food was observed for P. juponicus (Oshima, 1936; Inoue, 1978), P . interruptus (Mitchell, 1971) and J. edwurdsii (Tong et al., 1997). Cultured Artemiu juveniles are often used as food for older phyllosomas, in addition to mussels. In contrast, no feeding behaviour on Artemiu nauplii was reported in J. edwurdsii (Batham, 1967), P . urgus (Moe, 1991) or Ibucus ciliutus and Ibacus noverndentutus (Doutsu et al., 1966).The availability of Artemiu nauplii as a food source seems to be dependent on their concentration in the culture water. The optimum density of Artemiu nauplii for the first and third instar phyllosomas of P.juponicus was tested by Inoue (1978, 1981). The size of Artemiu used was 0.47 and 1.12 mm for the first and third instar phyllosomas, respectively. The number of Artemiu nauplii (density l/ml) eaten per hour for the first and the third instars was about 0.4 and 0.3,

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respectively. The number of Artemia nauplii eaten increased to 1 and 0.8/h with an increase in Artemia density up to 4/ml. At this level, the number eaten became stable regardless of increased Artemia density. In the culture experiments at Sanriku, the initial density of Artemia nauplii was maintained at 1-3/ml (Kittaka, 1988; Kittaka et al., 1988; Kittaka & Kimura, 1989). Tong et al. (1997) experimented with the effect of Artemia of 2-3 mm on the growth and survival of early-stage J. edwardsii phyllosomas. The threshold below which food became limiting, measured as a significant delay in moulting, was <2,4, 8 and 12 Artemia nauplii per day for instars 1 and 2, instar 3, instars 4 and 5 and instar 6, respectively.

28.4.2

Mytilus edulis

The gonad of the mussel M . edulis is one of the most effective foods for phyllosomas. Oshima (1936) observed a phyllosoma to ingest mussel flesh into the midgut gland after feeding. However, the results of the early studies were pessimistic as mussel flesh tangled in the pereiopods and water quality subsequently deteriorated (Oshima, 1936; Dexter, 1972). Until recently, in some hatcheries phyllosomas were cultured in a finger bowl by placing a piece of mussel on their mouthparts and with frequent water changes. Marine crustaceans are unable to synthesize 10 kinds of amino acids: arginine, methionine, valine, threonine, isoleucine, leucine, lysine, histidine, phenylalanine and tryptophan, and the highly unsaturated fatty acids: linoleic (18:2n-6), linolenic (18:3n-3), icosapentaenoic (20:5n-3) and docosahexaenoic (22:6n-3) acids (Kanazawa, 1994). Marine bivalves contain essential amino acids and fatty acids. Babynecked clams, Tapes philippinarum, were used as food for growout of penaeids prior to formulation of artificial diets (Hudinaga & Kittaka, 1966). Feeding experiments on penaeids with mussels showed the high food value of mussels because of their balanced and high contents of essential amino acids and fatty acids (Kittaka, 1987a). Mussels inhabit fairly clean environments such as rocky shores or aquaculture rafts, unlike baby-necked clams which inhabit muddy bottoms. Mussels were used as food in the culture system (Fig.28.1). Mussel pieces of about 2 mm3 are suitable food for the advanced instars as they catch food with their well-developed pereiopods as shown in Fig. 28.2 (Kittaka, 1994a, b). Pereiopods develop with each instar. The third pereiopods are functional in the first phyllosoma instar. The fourth pereiopods become functional to catch food from about the sixth instar for P .japonicus until the final stage, whereas for Jams spp. the fifth pereiopods become the most functional after about the seventh instar. The pereiopods of J. edwardsii are equipped with setae with a pore on the tip or median part; conoid type setae were observed on the base of the dactylus and short spine setae on the dactylus and propodus (Otowa & Kittaka, unpubl.). These are presumed to be chemosensory sensilla, and their distribution and location seem to be related to the feeding actions of the pereiopods (Kittaka, 1994a, b).

5 16 Spiny Lobsters: Fisheries and Culture

Fig. 28.2 Midstage phyllosoma larva of Panulirusjaponicus. The animal is catching a piece of mussel with the fourth pereiopod and its midgut is full of food.

28.4.3

Fish larvae

A variety of fish larvae was used for phyllosoma culture in the early years. Doutsu et af. (1966) and Moe (1991) were able to culture the phyllosomas for a short period by feeding with fish larvae. Predacious feeding on fish larvae was observed for the slipper lobster I. ciliatus and I. novemdentatus (Doutsu et al., 1966) and P . argus (Moe, 1991). The fish larvae were stabbed with dactyls of the third pereiopods (the fourth pereiopods are not yet developed at the first instar) and then were transferred to the mouthparts. The prey was grazed on from the tail by holding it with the second and third maxillipeds (the first maxillipeds are rudimentary). The feeding behaviour of the phyllosomas shows that they are primarily predators with the pereiopods, and secondarily plankton (such as Artemia nauplii) feeders with the maxillipeds and maxillae (Kittaka & Abrunhosa, 1997). Inoue (1978) suggested the best sequence of food to be: Artemia nauplii and juveniles for phyllosomas from the first to the fifth stage, field-caught arrow worms Sagitta and fish larvae to 137 days old, and then artificially cultured fish fry Lateolabrax japonicus of body length 4.5-7.5 mm and Limanda yokohamae of 4.5-9.5 mm. Two groups of the phyllosomas of J . verreauxi (185 days old after hatching) were cultured separately, feeding with the newly hatched larvae of sailfin sandfish

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Arctoscopus japonicus and mussels in combination for one group, and mussels exclusively for another group. The rate of metamorphosis was 77.3% for the former and 34.1% for the latter group, with an average duration of 116 and 136 days (301 and 321 days after hatching), respectively (Kittaka, 1997b). The fact that late-stage phyllosomas fed fish larvae and mussels in combination showed a better survival rate and shorter period before metamorphosis than those fed with mussels strongly suggests that fish larvae have a high nutritional value.

28.4.4

Food organisms found in the wild

In nature, interesting ‘riding’ behaviour by phyllosomas on jellyfish has been reported by several researchers (Shojima, 1963; Thomas, 1963; Herrnkind et al., 1976). This was observed for Scyllaridae but not for Palinuridae. Because of the absence of food particles in the gut of phyllosomas, it has been hypothesized that they are adapted for eating soft-bodied forms such as jellyfish (e.g. Phillips & Sastry, 1980). Feeding experiments showed that phyllosomas prey on jellyfish in a similar manner to mussels. The food value of jellyfish was compared with mussels for a 2-month period using the second instars of J.edwardsii phyllosoma. Jellyfish Aurelia aurita and Dactylometra pacijlca were given for the first month, and then Staurophora mertensi and Aequorea coerulescens for the second month. Survival rates of phyllosomas fed with jellyfish and mussels, separately, were 57.2% and 74.5% with moult frequencies of 2.30 and 3.45 times per individual during the 2month period, respectively (Kittaka, 1997a). The intermoult period from the third to the fourth instars was shorter for the jellyfish-fed group than for the mussel-fed group. A delay in moulting occurred in the former group, at the time when the jellyfish diet was changed. Staurophora mertensi and A . coerulescens may be less nutritious than A. aurita and D . pacijka. The water content of D. pacflica is 96%, and 21% of the dry weight is protein (Shinagawa et al., unpubl. data). Fatty acid analysis for Aurelia sp. showed that 2.0% of the dry weight is lipid and 22% of this lipid is highly unsaturated fatty acids (Holland et al., 1990). This suggests that jellyfish may be nutritionally satisfactory for phyllosomas. Studies on the chemical components and texture of gelatinous organismas in the ocean may be useful in formulating artificial foods for phyllosomas (Kittaka, 1997a).

28.5

Stage and instar

Development of the phyllosoma is expressed as either stage or instar. The former is determined by morphological changes and the latter relates to the number of moults. The relation between stage and instar is not known precisely. Based on plankton

5 18 Spiny Lobsters: Fisheries and Culture samples, 11 stages were described for P. argus (Lewis, 1951), P . interruptus (Johnson, 1956), P . inflatus (Johnson & Knight, 1966) and J . edwardsii (Lesser, 1978), nine stages for P . cygnus (Braine et al., 1979) and 10 stages for P . elephas (Bouvier, 1913). For P . japonicus, 11 stages were described from larval rearing by Inoue (1978). It was presumed that a series of stages or instars observed under laboratory condition may not be normal (Saisho, 1966b; Ong, 1967; Robertson, 1969; Inoue, 1978). However, examination of a series of moults by J . verreauxi suggests that it may be better to use instars as the sequence of the development, instead of the arbitrary staging, because metamorphosis was observed to occur consistently at the 17th instar (Kittaka et al., 1997). Appearance of phyllosomas is characterized by the development of pereiopods for the early-stage, abdomen for the midstage, and pleopods, uropods and gills for the late stage. Compared with Jusus spp., phyllosomas of P . juponicus have about 10 more instars at the midstage. Kittaka & Kimura (1989) examined the relation between stage and instar by monitoring five eighth-stage individual phyllosomas of P .japonicus. Most phyllosomas have six instars at the eighth stage, three at the ninth stage and three at the 10th stage. The eighth stage may be separated into two substages: pleopods were absent and uropods appeared as low buds in the first three instars, and pleopods appeared as low buds and uropods became bifid in the latter three instars. The intermoult period of the instars was stable at 11.5 (range 1&13) days for the eighth stage, 12.4 (range 11-15) days for the ninth stage, and 12.6 (range 1&16) days for the 10th stage. Exceptionally, one phyllosoma had nine instars at the eighth stage with the longer intermoult period of 16.1 (range 10-20) days. This phyllosoma repeated moulting without significant morphological change and died at the fourth instar of the ninth stage. From these results, it may be presumed that phyllosomas in good condition moult at regular intervals, while delay of moulting occurs in unhealthy individuals. The number of instars varies between species. In general, cool-temperate species have fewer instars with longer intermoult periods compared with warm-temperate species. Seventeen instars were confirmed for J . verreauxi (Kittaka et al., 1997), and presumably the same for J. edwardsii (Kittaka et al., unpubl. data) and J . lalandii (Kittaka, 1988). In contrast, two P . japonicus phyllosomas metamorphosed into pueruli after an estimated 29 instars (Kittaka & Kimura, 1989). Because observations were made using delicate moult shells of phyllosomas in a communal culture tank with very low survival of phyllosomas, further observations are required to elucidate the sequence of instars. Yamakawa et al. (1989) observed 28 instars for an individually cultured phyllosoma at Mie Prefecture, and Nonaka (1996) estimated an average 27 (range 20-31) instars for a total of 219 metamorphosed individuals at Minami-Izu, Shizuoka Prefecture. For P . elephas, Bouvier (1913) described 10 stages using wild-caught phyllosomas. The phyllosomas of P . elephus hatched out at a more advanced stage with a larger size compared with Jasus and Punulirus species. The initial total length is about 2.8 mm long for P . elephas, which is much longer than about 1.6 and 2.0 mm in P.

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japonicus and J . edwardsii, respectively. In the first instar of P . elephas, the third pereiopods elongate, while they appear as a segment in Jams and Panulirus species. The uropods are observable as swellings in the second instar of P . elephas, but do not reach this level of development until the 11th instar in Jusus spp. (Kittaka & Ikegami, 1988; Kittaka, 1994a, b). In the laboratory, a phyllosoma of P . elephus at the ninth instar metamorphosed into the puerulus after a period of 132 days in 1988 (Kittaka & Ikegami, 1988) and at the seventh (estimated) instar only 65 days after hatching (Kittaka, 1997). The repeated moulting found in the midstage phyllosomas of P . japonicus is considered to be a kind of ‘moratorium’ in their development, which controls the timing for their coastal recruitment. In contrast, phyllosomas of P . elephus shorten the developmental stages in order to settle within 1 year of hatching.

28.6

Metamorphosis

Moulting begins with separation of the new cuticle from the old cuticle. This is observable as whitening in the antennae (Kittaka et al., 1997), increasing thickness of the abdomen (Kittaka, 1988; Kittaka et ul., 1988, 1997; Kittaka & Kimura, 1989), occasional scraping of the pleopods with the third maxillipeds (Kittaka, 1988) and atrophy of the midgut gland (Kittaka & Kimura, 1989; Kittaka et al., 1997) about 1 week before moulting. The phyllosomas cease feeding (Kittaka et al., 1988, 1997; Kittaka & Kimura, 1989), the midgut gland becomes transparent (Kittaka et al., 1997), and pleopods and uropods show development a few days before moulting (Kittaka, 1988). On the day of metamorphosis, the body looked whitish and opaque (Kittaka, 1988), and swimming activity decreased (Kittaka et al., 1997). The phyllosomas bent their abdomens occasionally and beat their pleopods vigorously (Kittaka et al., 1997). The eyestalks became flaccid (Kittaka, 1988; Kittaka et al., 1988; Kittaka & Kimura, 1989), then they ceased swimming (Kittaka et al., 1997) and began to moult. First, absorption and removal of new cuticle occurred in the cephalothorax region (Kittaka & Kimura, 1989; Kittaka et al., 1997). The newly formed cephalothorax emerged from the fused portion of the old head and thorax (Kittaka et al., 1997). The abdomen then emerged as it bent back and forth, followed by emergence of the pereiopods (Kittaka et al., 1997). Finally, the antennae emerged as the puerulus flexed against the water current (Kittaka et ul., 1997). Metamorphosis occurred for J. lalandii at 00.20 h on 3 June 1987 (Kittaka, 1988), which was the first success in the complete development for palinurid species. The Jusus hybrid moulted at 19.30 h on 31 July 1987 (Kittaka et al., 1997). The body was almost colourless and transparent except for eyes and gills (Kittaka, 1988). The puerulus swam in a rotating progression with the second antennae extended forward (Kittaka, 1988). Swimming was directed from the bottom to the surface, or in the reverse direction (Kittaka, 1988). Sometimes, the puerulus lay on its back and moved forwards with vigorous beating of pleopods (Kittaka, 1988). The pueruli of J .

520 Spiny Lobsters: Fisheries and Culture verreauxi have long antennae relative to body length compared with other species (Kittaka et al., 1997). As they swam with extended second antennae and pereiopods, their long antennae often twisted in a 30-litre tank (Kittaka et al., 1997). This malformation did not occur in a 100-litre tank. Panulirus japonicus metamorphosed in similar manner to Jasus spp.

28.7

Puerulus culture

Results of observations on the feeding behaviour of the puerulus stage are contradictory. Moulting of the puerulus into the post-puerulus stage was reported for P . japonicus by Kinoshita (1934), who reared wild-collected pueruli in the laboratory using fish or shrimp flesh for food. In contrast, the wild-caught pueruli for P . argus (Herrnkind & Butler, 1986) and P. cygnus (Chittleborough & Thomas, 1969) appear not to feed. However, these reports lack observations on the early puerulus stage. Non-feeding during the puerulus stage was elucidated by complete development in laboratory for J . lalandii (Kittaka, 1988), Jusus hybrid (Kittaka et al., 1988), P . elephas (Kittaka & Ikegami, 1988), P . japonicus (Kittaka & Kimura, 1989), J . verreuuxi (Kittaka et al., 1997) and J. edwardsii (Kittaka et al., unpubl. data). This is supported by the developmental changes in morphology of mouthparts and foregut of J . edwardsii (Nishida et al., 1990) and mouthparts of P . argus (Wolfe & Felgenhauer, 1991) and P . cygnus (Lemmens & Knott, 1994) in comparison with the late-stage phyllosomas and the first-moult post-puerulus. In the early-stage puerulus of J. edwardsii, the presence of paired fat bodies, in contact with the midgut gland, were found in the haemocoel (Takahashi et al., 1994). In the advanced-stage phyllosomas, the fat bodies became much smaller than in the early stage. The epithelial cells of the midgut gland showed absorption of the lipid, presumably from the fat bodies. These histochemical results suggest that the puerulus uses materials stored in the fat bodies as an energy source during its nonfeeding stage (Takahashi et al., 1994). Lemmens (1994) also found high levels of ashfree dry weight, carbon and carbon:nitrogen ratio in late-stage phyllosomas and early-stage pueruli compared with late-stage pueruli for P . cygnus. These facts indicate that nutrients stored during the phyllosoma stage are consumed for swimming and development during the non-feeding puerulus stage. Better survival rates were shown for the wild-caught pueruli (Kinoshita, 1934), while poor survival rates were common for the pueruli which metamorphosed in the laboratory (Kittaka, 1994a, b). For J. verreauxi, 168 pueruli were artificially cultured in 1991. Only 29 pueruli moulted into the first juvenile, with a poorer survival rate of 17.2%. Most pueruli died within 2 days after metamorphosis (Kittaka et al, 1997). Similarly, a relatively poor survival rate of 37.5% was reported during the puerulus stage of P . japonicus produced at Minami-Izu spiny lobster hatchery in a 5-year period from 1989 to 1993 (Sekine, 1996). These facts suggest that nutrient storage in

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these cultured pueruli may be not sufficient to support energy consumption and development during their non-feeding stage. In contrast, out of 49 pueruli only 12 died, with a 75.5% survival rate for J . verreauxi in 1997 (Kittaka, 1997b). The better survival rate in 1997 is considered to be the result of improved nutritional conditions during the phyllosoma stage (as mentioned in Section 28.4) and of using larger culture containers: 30-litre containers were mainly used in 1991, whereas 100-litre containers were used in 1997. Because newly metamorphosed pueruli drifted, rotating with the current in the small containers, their long paired second anntenae were often twisted together. This problem was solved by using the large culture containers. The puerulus settles within a few days after metamorphosis. Selection of the substrate differs with the species (Herrnkind et al., 1994). The collecting device of artificial seaweed is applied for P . cygnus (Phillips, 1972), and artificial crevices for J . edwardsii (Booth, 1979). As the puerulus is a non-feeding stage and exhibits gregarious behaviour, its substrate preference is considered primarily to be an adaptation to escape from predators. As they are not cannibalistic, the presence of shelters is not essential. However, installing shelters in culture tanks seems to be effective in providing sufficient settling space for the puerulus. The design of a puerulus culture tank is shown in Fig. 28.3. The puerulus stage lasts for about 14 days for warm-temperate P . japonicus and 25 days for cool-temperate J . verreauxi. The juveniles begin to take food, but they are cultured in the same tank with the pueruli. Their environmental requirements and growth patterns are discussed in Chapter 30.

Air supply

Screen

Shelter Fig. 28.3 Tank for the culture of the puerulus stage of spiny lobster.

522 Spiny Lobsters: Fisheries and Culture 28.8

Case studies

Research by the present author has attempted to clarify the environmental and nutritional requirements for phyllosomas by trial and error under laboratory conditions. The basic technology used so far was temperature control at 20°C for the cool-temperate Jams and Palinurus species and 25°C for the warm-temperate Panulirus species, water quality control with inoculation of microalgae, such as Nannochloropsis sp. (marine bacteria showed some success) and supply of mussels (Mytilus edulis) as food for the entire period except for the initial instars. A general overview of the culture results is given in the above sections. In this section, some details of the culture experiments are given for several of the species. Culture technology is progressing on an experimental scale. A review of each step in development may be useful to others as they attempt to develop culture methods and to establish commercial-scale aquaculture of spiny lobsters. Water quality and food requirements for the culture of phyllosomas are shown in Table 28.4.

28.8.1

Jasus species

The genus Jasus is divided into two subgenera: the lalandii group and the verreauxi group. The larvae of Jaws spp. hatch out as naupliosoma before proceeding to the phyllosoma stage (Gilchrist, 1916; von Bonde, 1936; Silberbauer, 1971). After hatching, the larvae swim to the surface with rapid beating of the second antennae. About 10-20 min after hatching their folded appendages are extended and they enter the phyllosoma stage. The number of instars during the phyllosoma stage of development was determined to be 17 for J . verreauxi, although only slight morphological changes were observable after the 15th instar. Jams lalandii

The initial number of first-instar phyllosomas introduced was 15 800 into a 100-litre culture tank. The number decreased to 92, two and one individuals at 63,96 and 224 days after hatching, respectively. The remaining single individual metamorphosed into the puerulus stage 306 days after hatching. Thus, survival rate during the early stage was very low, but after midstage development, a 50% survival rate was obtained (Kittaka, 1988). Eleven stages were reported for this species by Silberbauer (1971) and Lesser (1978). In the culture experiment, the relationship between stage and instar became clear after the eighth stage, and there were observed to be two, three, two and a single instar at the eighth, ninth, 10th and 11th stage, respectively (Kittaka, 1988). This succession of instars was also confirmed for J . verreauxi (Kittaka et af., 1997). Because of the similarity of development between the Jasus species, the total number of instars in J . lalandii may be also estimated to be 17 (Kittaka et al., unpubl. data).

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Table 28.4 Culture conditions for phyllosomas by the microalga method and the recirculatefilter method Conditions

Reference

Culture water: filtered through 5-10 pm Water temperature: 20°C for Jasus and Palinurus; 25°C for Panulirus Salinity: 33-36 pH: 8.c8.6 Density of phyllosoma: 1&20/ml Food: Arternia nauplii (initial stage); mussels and fish larvae (mid- and late stage) Ammonia-N: < 1.4 mg/l (microalga method) COD: < 1.2 mg/l (microalga method) <1.8 mg/l (recirculate-filter method) Nunnochloropsis density: 2 x lo6 (initial) to 20 x lo6 (maximum) cells/ml Bacterial number: around 103-104 CFU/ml (microalga method)

Kittaka (1994b) Kittaka (1994b)

around 10'-102 CFU/ml (recirculate-filter method) Bacterial composition: dominated by Pseudornonas and Vibrio Change of culture water: every 2 4 weeks (microalga method)

Kittaka (1994b) Kittaka (1994b) Kittaka et al. (1997a) Kittaka (1997a, b) Kittaka (1994) Kittaka (1994a, b) Kittaka et al. (unpubl.) Shioda et al. (1997)

Kittaka (1994a, b), Igarashi

& Kittaka (2000)

Kittaka (1994a, b), Igarashi

& Kittaka (2000)

Kittaka (1994b), Kittaka et al. (1997), Shoida et al. (1997)

every 4 8 weeks (recirculate-filter method) COD, chemical oxygen demand; CFU, colony-forming units.

Final-stage phyllosomas underwent a drastic change in appearance and behaviour as they approached metamorphosis. The body became whitish and developed pleopods, and uropods beat frequently. The newly metamorphosed puerulus was about 20 mm body length [lo mm carapace length (CL)], almost colourless and tranparent. The puerulus swam with the second antennae and the pereiopods extended forward. About 8 days after metamorphosis, the puerulus began to cling on to rocks. No feeding behaviour was observed on the mussels or seashore stones with fouling organisms introduced into the tank. The puerulus gradually changed its swimming behaviour, namely jumping backwards and walking with pereiopods. Pigmentation of the body became more pronounced. The puerulus survived for 31 days, perhaps near to moult (Kittaka, 1988).

524 Spiny Lobsters: Fisheries and Culture A hybrid of the genus Jasus A mating experiment between a female of J. novaehollandiae and a male J. edwardsii was successful (Kittaka et al., 1988). This fact is one of the bases on which both are now considered the same species (Booth et al., 1990). Rearing the phyllosomas began with an initial number of 1000, and two individuals survived 51 days after hatching. Of these two individuals one metamorphosed into the puerulus stage 319 days after hatching and the other survived for 325 days. The former became malformed during metamorphosis and died several days later, while the latter died without moulting into the final instar. The rearing conditions were similar to the case of J. lalandii (Kittaka et al., 1988) during the early and midstages. However, N . oculata was not added to the culture water for the last 2 months. This might be a reason for the unsuccessful metamorphosis in the culture of this species.

Jams edwardsii In 1991, a total of 12 000 first instars was cultured at initial densities of 30 and 90 per litre in two 100-litre tanks. Survival rates of phyllosomas were 2.9, 1.2 and 0.3% at 100, 200 and 300 days after hatching, respectively. Two groups of 30 third instars were selected about 30 days after hatching and cultured separately in two 100-litre tanks. In one tank, six individuals metamorphosed into the puerulus 21 1-274 days after hatching at the 15th instar. These individuals died during metamorphosing or on the day of metamorphosis. In another tank, a total of 10 individuals metamorphosed 224-302 days after hatching:one, two, six and one individual at the 13th, 14th, 15th and 17th instar, respectively. The 13th and 14th instars died during metamorphosing, and the 15th instars died within several days after metamorphosis. Only a single 17th instar successfully metamorphosed and moulted into the juvenile stage (Kittaka et al., unpubl. data). In 1998, 1500 first instars were cultured in a recirculatefilter system. At the fifth instar, 127 fifth instars survived. They were fed with hatched larvae of red sea bream (Pagrus major), and goldstriped amberjack (Seriola lalandi). Newly hatched larvae of tidepool gunnel (Pholis major) were fed for 33 days in combination with mussels, from the ninth to the 12th instar. For this 33-day period, the survival rate was 90%, and the average intermoult period was 10 days. Fish larvae were not fed after the 12th instar. The numbers of surviving phyllosomas were 1 15, 115, 110, 106, 86 and 66 at the 12th, 13th, 14th, 15th, 16th and 17th instars, respectively. Six final-stage phyllosomas metamorphosed into the puerulus stage. All of them died during metamorphosis or within a single day after metamorphosis. These culture experiments suggest that nutritional requirements for the late-stage phyllosomas of J . edwardsii may differ from their early and midstages.

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Jams verreauxi

Approximately 190 and 1500 first instars were cultured in a 30-litre tank and a 100litre tank, respectively, in 1991 by the microalga method. Culture water was changed about every 22-24 days (Kittaka et al., 1997). A total of 24 and 144 final instar phyllosomas metamorphosed to pueruli after 17 (less often 16) moults, with survival rates of 12.6% and 9.6% after 189-273 (average 234) days and 224-359 (average 263) days, respectively. The survival rate from the first instar to the puerulus stage was 12.6% and 9.6%, respectively. A comparative result was obtained in 1996 with an average survival rate of 6.8% and an average duration of 270 days for the phyllosoma stage (Kittaka, 1997b). These results suggest that commercial-scale culture of J. verreauxi may be feasible. The most useful feature to distinguish mid- and late-stage phyllosomas from other Jasus species was the development of a biramous fifth pereiopod seen only in J . verreauxi (McWilliam & Phillips, 1987). Culture of phyllosomas revealed that an exopod appeared as a bud in the fourth instar and that a setose exopod developed on the third maxilliped (Kittaka et al., 1997).

28.8.2

Punulirus juponicus

A relatively high culture density of 200 first instars per litre was used in the previous experiments. Owing to heavy mortality, the density decreased rapidly during the early stages. Survival rate was very poor up to midstage development, but became higher by the late stage. Three phyllosomas reached the final instar. Two phyllosomas metamorphosed into pueruli 340 and 39 1 days after hatching (Kittaka & Kimura, 1989). An improvement on the low survival rate was achieved in 1991 by changing the culture water every 2-week period. A total of 2000 and 1500 first instars was cultured in 30-litre containers, with a survival rate at about 15% for the initial 150 days in culture (Shioda et al., 1997). The intermoult period was relatively constant at about 6 and 7 days for the first to the second instar, and the second to the third instar, respectively. The third stage is composed of two instars and lasts for about 18 days. After this stage, precise determination of the instars was difficult because phyllosomas were cultured communally. The elongation and bifurcation of the fourth pereiopods, the number of setae on the exopods of the fourth pereiopods, and development of uropods are the characteristics used to identify the instars at the midstage of development. After the eighth stage, individual monitoring became possible. Development of uropods and pleopods is the characteristic used to separate the stages. Phyllosomas from the eighth to the 1 lth stage were observed to have six, three, three and a single instar, respectively. The intermoult period ranged between 10 and 21 days (average 12.9 days) (Kittaka & Kimura, 1989).

526 Spiny Lobsters: Fisheries and Culture Phyllosomas of P . japonicus were often found to lose the endopods of the fourth pereiopods. The lost endopods were regenerated at the following moult. However, these regenerated endopods seemed to be fragile and the growth of phyllosomas was retarded owing to repeated loss of the endopods. This might be a reason for the conflicting information about the number of instars. The period of the final instar was 12 days. The puerulus moulted into the first juvenile about 15 days after metamorphosis (Kittaka & Kimura, 1989).

~ 8 . 3

Palinurus elephas

Between 1000 and 5000 first-instar larvae were cultured in a 100-litre culture tank. Although the phyllosomas hatched out at an advanced stage, the survival rate was very low during the early instars. The survival rate for the first instar was lower than 5% when they were fed Artemia nauplii only. Only one and two phyllosomas metamorphosed into the puerulus stage from 132 to 148 days after hatching (Kittak & Ikegami, 1988; Kittaka & Kanamaru, unpubl. data). In 1996, 300 first-instar phyllosomas were cultured fed with both mussels and newly hatched sailfin sandfish larvae. Three phyllosomas survived to the final stage. One metamorphosed to the puerlus stage only 65 days after hatching, through the preceeding six moults that occurred 7, 18, 26, 33, 44 and 57 days after hatching (Kittaka, 1997b). The diatoms Thalassiosira sp. and Nitzschia sp. were propagated in the culture water, beginning at the fourth instar and continuing until the final stage. In the previous experiment, it was found that the survival rate was improved when they were raised in the culture water inoculated with the diatom Chaetoceros sp. (Kittaka & Abrunhosa, 1997). Although Thalassiosira sp. had a high content of total fatty acids (18.5% of dry weight) with a high percentage of icosapentaenic acids (approximately 27% of the total fatty acids) (Ishikawa, Teshima & Kittaka, unpubl. data), it is unclear whether the diatoms were used as food, or whether their only role is to control water quality.

28.9

Discussion

Seed, water and food are three important factors in aquaculture. Because of the difficulty in phyllosoma culture of spiny lobster, seed (pueruli) were not available in the hatchery for many years. Recent developments in larval culture have made it possible to rear phyllosomas from egg stage to metamorphosed form, and then the juvenile stage. The species so far showing complete development comprise three genera: Jasus, Panulirus and Palinurus. However, progress in phyllosoma culture is very slow, and culture of phyllosomas to pueruli has not yet been achieved on a large scale.

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527

Phyllosomas were successfully cultured under laboratory conditions with seawater inoculated with microalga, N . oculata, and fed with mussels, M . edulis. Neither Nannochloropsis nor mussels have been found offshore where the nursery is formed for phyllosomas with oceanic currents. The role of microalgae is particularly important for the control of both bacteria and water quality. When the physiological condition of N . oculata worsened, the microflora had a tendency to change to less suitable bacteria, associated with an increase in bacterial number (see Chapter 29). Once attachment of bacteria had occurred in the phyllosomas, their chemoreceptive and mechanoreceptive functions appeared to be impaired, probably because their sensory organs are distributed on the surface of the trunk and the pereiopods. Phyllosomas can be cultured successfully in small numbers without microalgae. In such cases, bacterial numbers were kept lower and suitable bacterial strains predominated in the microflora (see Chapter 29). The recirculate-filter system with coral sand seemed to be more effective in controlling bacterial numbers than Nunnochloropsis. Nevertheless, the culture results were no better than the microalga method, owing to eventual infection by pathogenic bacteria. This implies that undesirable bacterial growth may occur under conditions with a small number of bacteria. In commercially important crustacean species, penaeid shrimp aquaculture is established as an important food industry in Japan (Shigueno, 1975) and in tropical and subtropical zones. The breakthrough for mass culture was achieved by development of an effective larval culture method. Penaeid shrimp hatch out as nauplius and undergo zoea, mysis and post-larval stages. They begin to take food at the zoea stage. The type of food is phytoplankton and zooplankton for zoea, mysis and early post-larval stages, and then detritus for the mid- and late post-larval stages and juvenile stage (Hudinaga & Kittaka, 1966, 1967). The duration from hatching until metamorphosis into the post-larvae is about 10 days, and the post-larval stage is about 20 days. The large-scale culture method developed by Hudinaga & Kittaka (1967) establishes a series of food chains in accordance with the developmental stage of the larvae. Although the bacterial number in penaeid culture water was much higher than in phyllosoma culture water (Igarashi & Kittaka, 1991), very short moult intervals for penaeid larvae make them free from the risk of contamination and disease. It will be apparent that the difficulty in phyllosoma culture is caused by both their relatively long intermoult intervals and their long larval life. Survival rates shown for P . juponicus phyllosoma culture were suggestive: about 11.5% for initial survival, about 150 days in 1991 (Kittaka et a[., 1997), and about 28.6% for late survival, about 250 days in 1988 (Kittaka & Kimura, 1989). When combined, these survival rates give an estimated survival rate of 3% for the phyllosoma stage. Once a 3% survival rate has been attained, it is not so difficult to achieve a 10% survival rate, as already shown in J. verreauxi. The most drastic effects in improving survival rate and intermoult period were evident for the phyllosomas fed with larvae of cold-water fish species. Hatched

528 Spiny Lobsters: Fisheries and Culture

larvae of the sailfin sandfish A . japonicus contained icosapentaenoic acid (EPA) at levels 10 times higher and docosahexaenoic acid (DHA) at 500 times higher than Artemia, which are commonly used in phyllosoma culture (Ishikawa, Teshima & Kittaka, unpubl. data). From the culture results described previously, it is apparent that nutritional requirements differ between species. The late-stage phyllosomas of J. verreauxi metamorphosed when fed with mussels only, while the majority of J . edwardsii did not succeed in metamorphosis when fed with mussels only. This may indicate that the late-stage phyllosoma of J. edwardsii requires highly unsaturated fatty acids (HUFA) in larger amounts than does J . verreauxi. Improvements in survival rate have been shown for the early instars of the most species. The only exception is P . elephas, even though they hatch at a larger size and more advanced developmental stage, and metamorphose after a shorter period than other species. Artemia nauplii were consumed by the first instar, but the survival rate was very poor, with prolonged intermoult days compared with other species. However, they showed vigorous feeding behaviour on sailfin sandfish larvae and moulted into the second instar with a much better survival rate and shorter intermoult period. This fact indicates that phyllosomas of P . elephas also have a high requirement for HUFA beginning at the first instar. However, it is prudent for feeding fish larvae to be limited to experimental purposes only. Analysis of the biochemical composition, and measurement of the shape and texture of fish larvae as well as gelatinous marine organisms will be helpful in developing formulated artificial food. At present, effective phyllosoma culture tanks have a capacity of only 30100 litres. The scale of the culture system could be enlarged with the microalga method with microflora control, while it is limited in the recirculate-filter system. One advantage with the latter method is the easy viewing of the appearance and behaviour of phyllosomas because of the transparency of the culture water. Therefore, the recirculate-filter method will be effective for experimental purposes, particularly to clarify the relationship of stages and instars which has remained unconfirmed for many species. However, for the microalga method no species of microalgae other than N . oculat and some diatom species has been examined. Selection of more suitable species of microalgae and bacterial strains will be important to establish commercial-scale larval production of spiny lobster.

References Archer, S . & Nickell, L. (1997) An Evaluation of the Aquaculture Potential of the Spiny Lobster Palinurus elephas. Dunstaffnage Marine Laboratory, Oban, Scotland, UK, 62 pp. Batham, E.J. (1967) The first three larval stages and feeding behaviour of phyllosoma of the New Zealand palinurid crayfish Jusus edwardsii (Hutton 1875). Trans. R. Sot. N . Z . , 9(6), 53-64. Bonde, C. von (1936) The reproduction, embryology and metamorphosis of the Capecrawfish Jams lalandii (Milne Edwards) Ortman. Invest. Rep. Fish. Mar. Biol. Surv. S. Afr., 6, 5-25.

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Booth, J.D. (1979) Settlement of the rock lobster, Jams edwardsii (Decapoda: Palinuridae), at Castlepoint, New Zeland. N.Z. J. Mar. Freshwat. Res., 13, 395-406. Booth, J.D. (1996) Phyllosoma raised to settlement. Lobster Newslett., 8(2), 1, 12. Booth, J.D., Street, R.J. & Smith, P.J. (1990). Systematic status of the rock lobsters Jams edwardsii from New Zealand and J. novae-hollandiae from Australia. N . Z . J. Mar. Freshwat. Res, 24, 239-49. Bouvier, M.E.-L. (I91 3) Observations nouvelles sur le development larvaire de la langouste commune (Palinurus vulgaris Latr.). C.R. Acad. Sci. (Paris), 157, 45743. Braine, S.J., Rimmer, D.W. & Phillips, B.F. (1979) An illustrated key to the phyllosoma stages of the western rock lobster Panulirus cygnus George, on the notes on the length frequency data. CSIRO Div. Fish. Oceanogr. Rep., No. 102, pp. 1-13. Chittleborough, R.G. & Thomas, L.R. (1969) Larval ecology of Western Australian marine crayfish, with notes upon other palinurid larvae from the eastern Indian Ocean. Aust. J. Mar. Freshwat. Res., 20, 199-223. Dexter, D.M. (1972) Moulting and growth in laboratory reared phyllosomas of the California spiny lobster, PanuZirus interruptus. Calif. Fish. Game, 58, 107-15. Doutsu, Y . , Seno, K. & Inoue, S. (1966) Rearing experiments on early phyllosomas of Ibacus ciliatus (von Siebold) and I. novemdentatus Gibbies (Crustacea: Reptantia). BUN. Fac. Fish. Nagasaki Univ., 21, 181-94 (in Japanese). Gilchrist, J.D.F. (1916) Larval and post-larval stages of Jasus lalandii (Milne Edwards) Ortmann. J. Linn. Soc., 33, 101-25. Hattori, T. & Oishi, Y. (1899) Hatching experiment on Ise lobster. No. 1. Rep. Imp. Fish. Inst., 1, 76132 (in Japanese). Herrnkind, W.F. & Butler, M.J. IV (1986) Factors regulating postlarval settlement and juvenile microhabitat use by spiny lobster, Panulirus argus. Mar.Eco1. Prog. Ser., 34, 23-30. Hermkind, W.F., Halusky, J. & Kanciruk, P. (1976) A futher note on phyllosoma larvae associated with medusae. Bull. Mar. Sci., 26, 11tk12. Herrnkind, W.F., Jernakoff, P. & Butler, M.J. IV (1994) Puerulus and post-puerulus ecology. In Spiny Lobster Management (Ed. by B.F. Phillips, J.S. Cobb & J. Kittaka), pp. 213-29, Fishing News Books, Blackwell Scientific Publications, Oxford, UK. Holland, D.L., Davenport, J. & East, J. (1990) The fatty acid composition of the leatherback turtle Dermochelys coriacea and its jellyfish prey. Journ. Mar. Biol. Ass. U.K., 70, 761-70. Hudinaga, M. & Kittaka, J. (1966) Studies on food and growth of larval stage of a prawn, Penaeus japonicus, with reference to the application to practical mass culture. In$ Bull. Planktol. Jpn, 13, 83-94. Hudinaga, M. & Kittaka, J. (1967) The large scale production of the young Kuruma prawn, Penaeus japonicus Bate. In$ Bull. Planktol. Jpn, Commemoration Number of Dr Y . Matsue, 546. Hughes, J.T., Shleser, R.A. & Tchobanoglous, G. (1974) A rearing tank for lobster larvae and other aquatic species. Prog. Fish. Cult., 36, 129-32. Igarashi, M.A. & Kittaka, J. (1991) Bacteriological character in the culture water of penaeid, homarid and palinurid larvae. Nippon Suisan Gakkaishi, 57, 2255-60. Igarashi, M.A. & Kittaka, J. (2000) Water quality and microflora in the culture water of phyllosomas. In Spiny Lobsler: Fisheries and Culture (Ed. by B.F. Phillips & J. Kittaka), pp. 533-5. Fishing News Books, Blackwell Scientific Publications, Oxford, UK. Illingworth, J., Tong, L.J., Moss, G.A. & Pickering, T.D. (1997) Upwelling tank for culturing rock lobster (Jasus edwardsii) phyllosomas. Mar. Freshwat. Res., 48, 935-40. Inoue, M. (1965) On the relation of amount of food taken to the density of size of food in phyllosoma of the Japanese spiny lobster Panulirus japonicus (von Siebold). Nippon Suisann Gakkaishi, 31, 902-6 (in Japanese).

530 Spiny Lobsters: Fisheries and Culture Inoue, M. (1978) Studies on the cultured phyllosoma larvae of the Japanese spiny lobster Panulirus japonicus I. Morphology of the phyllosoma. Nippon Suisan Gakkaishi, 44,457-75 (in Japanese). Inoue, M. (1981) Studies on the cultured phyllosoma larvae of the Japanese spiny lobster, Panulirus japonicus (von Siebold). Special Report Kanagawa Prefectural Fisheries Experimental Station, No.1, pp. 1-91 (in Japanese). Inoue, M. & Nonaka, M. (1963) Note on the cultural larvae of the Japanese spiny lobster Panulirus japonicus (von Siebold). Nippon Suisan Gakkaishi, 29, 21 1-18 (in Japanese). Johnson, M.W. (1956) The larval development of the California spiny lobster, Panulirus interruptus (Randall), with notes on Panulirus gracilis Streets. Proc. C a l g Acad. Sci., 29, 1-19. Johnson, M.W. & Knight, M. (1966) The phyllosoma larvae of spiny lobster Panulirus inj7ufus (Bouvier). Crustaceana, 10, 3147. Kamiya, N., Yamakawa, T. & Tsujigado, A. (1986) Studies on larval rearing of Ise lobster. Annual Report. Mie Prefectural Fisheries Technological Centre, 1985, pp. 3G7 (in Japanese). Kanazawa, A. (1994) Nutrition and food. In Spiny Lobster Management (Ed. by B.F. Phillips, J.S. Cobb & J. Kittaka.), pp. 483-94, Fishing News Books, Blackwell Scientific Publications, Oxford, UK. Kinoshita, T. (I 934) Observations on puerulus of Japanese spiny lobster Panulirus japonicus. Doubutsugaku Zasshi (Zool. Mag.), 46, 391-9 (in Japanese). Kittaka, J. (1981) Ecological survey on lobster Homarus americunus and H. gummarus along the coasts of the North Atlantic Ocean. Report to the Ministry of Education, Culture and Science (Grant-in-Aid for Overseas Scientific Survey, Nos. 4041 52 and 504347), 77 pp (in Japanese). Kittaka, J. (1984) Ecological survey of lobster Homarus along the coasts of the Atlantic Ocean: ecology and distribution of Homarus capensis along the South Atlantic Ocean. Report to the Ministry of Education, Culture and Science (Grant-in-Aid for Overseas Scientific Survey, Nos. 56042009, 57041052 and 58043052), 118 pp. Kittaka, J. (1987a) Attaching organisms as feed. Utilization of attaching organisms for aquaculture. In Attaching Organisms and Aquaculture (Ed. by T. Kajihara), pp.108-18. KouseishaKouseikaku, Tokyo, Japan (in Japanese). Kittaka, J.( 1987b) Ecological survey of rock lobster Jaws in southern hemisphere: ecology and distribution of Jasus along the coasts of Australia and New Zealand. Report to the Ministry of Education, Culture and Science (Grant-in-Aid for Overseas Scientific Survey. Nos. 59042013, 60041066 and 61043061), 232 pp. Kittaka, J. (1988) Culture of the palinurid Jusus lalandii from egg stage to puerulus. Nippon Suisan Gukkuishi, 54, 87-93. Kittaka, J. (1990) Ecology and behaviour of puerulus of spiny lobster. La Mer, 28,255-9. Kittaka, J. (1994a) Culture of phyllosomas of spiny lobsters and its application to studies of larval recruitment and aquaculture. Crustaceana, 66, 2-17. Kittaka, J. (1994b) Larval rearing. In Spiny Lobster Management (Ed. by B.F. Phillips, J.S. Cobb & J. Kittaka.), pp. 402423, Fishing News Books, Blackwell Scientific Publications, Oxford, U.K. Kittaka, J. (1997a). Application of ecosystem culture method for complete development of phyllosomas of spiny lobster. Aquaculture, 155, 3 19-33 1. Kittaka, J. (1997b) Culture of larval spiny lobsters: a review of work done in northern Japan. Mar. Freshwat. Res., 48, 923-30. Kittaka, J. & Abrunhosa, F.A. (1997) Characteristics of palinurids (Decapoda; Crustacea) in larval culture. Hydrobiologia, 358, 305-1 1. Kittaka, J. & Ikegami, E. (1988) Culture of the palinurid Palinurus elephas from egg stage to puerulus. Nippon Suisan Gakkaishi, 54, 1149-54. Kittaka, J. & Kimura, K. (1989) Culture of the the Japanese spiny lobster Panulirus japonicus from egg to juvenile stage. Nippon Suisan Gakkaishi, 55, 963-70.

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Kittaka, J. & MacDiarmid, A.B. (1994) Breeding. In Spiny Lobster Management (Ed.by B.F. Phillips, J.S. Cobb & J. Kittaka.), pp. 384401, Fishing News Books, Blackwell Scientific Publications, Oxford, UK. Kittaka, J., Iwai, M. & Yoshimura, M. (1988) Culture of a hybrid of spiny lobster genus Jasus from egg stage to puerulus. Nippon Suisan Gakkaishi, 54, 413-17. Kittaka, J., Ono, K. & Booth, J. D. (1997) Complete development of the green rock lobster, Jams verreauxi from egg to juvenile. Bull. Mar. Sci., 61, 57-71. Lemmens, J.W.T.J. (1994) Biochemical evidence for absence of feeding in puerulus larvae of the western rock lobster, Panulirus cygnus (Decapoda: Palinuridae). Mar. Biol., 118, 383-91. Lemmens, J.W.T.J. & Knott, B. (1994) Morphological changes in external and internal feeding structures during the transition phyllosoma-puerulus-juvenile in the western rock lobster (Panulirus cygnus, Decapoda: Palinuridae). J . Morphol., 220, 2 17-80. Lesser, J.H.R. (1978) Phyllosoma larvae of Jasus edwardsii (Hutton) (Crustacea: Decapoda: Palinuridae) and their distribution off the east coast of the North Island, New Zealand. N.Z. J . Mar. Freshwat. Res., 12, 357-70. Lewis, J.B. (1951) The phyllosoma larvae of the spiny lobster Panulirus argus. Bull. Mar. Sci. Gurf Carib., 1, 89-103. McWilliam, P.S. & Phillips, B.F. (1987) Distinguishing the phyllosoma larvae of rock lobster species of the genus Jasus (Decapoda, Palinuridae) in the waters of Australia and New Zealand. Crustaceana, 67, 65-70. Mitchell, J.R. (I97 1) Food preference, feeding mechanisms, and related behaviour in phyllosoma larvae of the California spiny lobster, Panulirus interruptus (Randall). Master’s thesis, San Diego State University, San Diego, CA, USA. Moe, M.A., Jr. (1991) Lobsters - Florida, Bahamas, the Carribbean. Green Turtle Publications, Plantation, FL, USA, 511 pp. Nishida, S., Quigley, B.D., Booth, J.D., Nemoto, T. & Kittaka, J. (1990) Comparative morphology of the mouthparts and foregut of the final stage phyllosoma, puerulus, and postpuerulus of the rock lobster Jasus edwardsii (Decapoda, Palinuridae). J . Crust. Biol., 10, 293-303. Nishimura, M. (1983) Studies on larval production of Ise lobster - I. Annual Report, Mie Prefectural Hamajima Fisheries Experimental Station, 198 1, pp. &69 (in Japanese). Nishimura, M. & Kamiya, N. (1985) Studies on larval production of Ise lobster - 111. Results of phyllosoma culture in 1983. Annual Report, Mie Prefectural Fisheries Technological Centre, 1983, pp. 1 4 (in Japanese). Nishimura, M. & Kamiya, N. (1986) Studies on larval production of Ise lobster - IV. Results of phyllosoma culture in 1983. Annual Report, Mie Prefectural Fisheries Technological Centre, 1984, pp. 38-9 (in Japanese). Nishimura, M. & Kawai, H. (1984) Studies on larval production of Ise lobster - 11. Food value of Artemia cultured with yeast enriched with fat on phyllosomas. Annual Report, Mie Prefectural Hamajima Fisheries Experimental Station, 1982, pp. 1 4 (in Japanese). Nonaka, M. (1996) Aquaculture with particular emphasis on Ise lobster. In Aquaculture qf Prawn, Lobster and Crabs (Ed. by J. Kittaka, F. Takashima & A. Kanazawa), pp. 204-25. KouseishaKouseikaku, Tokyo, Japan (in Japanese). Nonaka, M., Oshima, Y. & Hirano, R. (1958) Rearing of phyllosoma of Ise lobster and moulting. Suisan Zoshoku (Aquiaculture), 5, 13-1 5 (in Japanese). Okauchi, M. (1987) On Tetraselmis tetrathele. Food Organisms Series, No. 6. Text for Course of Marine Farming Technology Course in 1987, Fisheries Agency and Japan Sea Farming Association, Tokyo, Japan. 38 pp. (in Japanese). Ong, K.S. (1967) A preliminary study of the early larval development of the spiny lobster Panulirus polyphugus (Herbst). Malay. Agric. J., 46(2), 183-90. Oshima, Y. (1936) Feeding habit of Ise lobster. Suisan Gakkai Ho (Bull. Fish. Sci.), 7 , 1 6 2 1 (in Japanese).

532 Spiny Lobsters: Fisheries and Culture Phillips, B.F. (1972) A semi-quantitative collector of the puerulus larvae of western rock lobster Panulirus longipes cygnus George (Decapoda, Palinuridae). Crustaceana, 22, 147-54. Phillips, B.F. & Sastry, A.N. (1980) Larval ecology. In The Biology and Management of Lobsters, Vol. 2, Ecology and Management (Ed. by J.S. Cobb & B.F. Phillips), pp. 11-57. Academic Press, New York, USA. Radhakrishnan, E.V. & Vijayakumaran, M. (1995) Early larval development of thespiny lobster Panulirus homarus (Linnaeus, 1758) reared in the laboratory. Crusfaceana, 68, 151-9. Robertson, P.B. (1969) The early larval development of the scyllarid lobster Scyllarides aequinoctialis (Lund) in the laboratory with a revision of the larval characters of the genus. Deep-sea Res., 16, 557-86. Saisho,T.( 1962) Note on the early development of phyllosoma of Panulirus japonicus. Mem. Fac. Fish. Kagoshima Univ., 11, 18-23. Saisho, T. (1966a) A note on the phyllosoma stages of spiny lobster Panulirus japonicus. Inj: Bull. Planktol. Japan., 13, 67-71. Saisho, T. (1966b) Studies of the phyllosoma larvae with reference to the oceanographic conditions. Mem. Fac. Fish. Kagoshima Univ., 15, 177-239. Sekine, S.(1996) Present status on phyllosoma culture. Saibai (Marine Farming), 74, 22-6 (in Japanese). Shigueno, K. (1975) Shrimp Culture in Japan. Association for International Technical Promotion, Tokyo, Japan, 153 pp. Shigueno, K. (1992) Shrimp culture industry in Japan. Development in Aquaculture and Fisheries Science, Vol. 23. In Marine Shrimp Culture: Principles and Practices (Ed. by A.W. Fast & L.J. Lester), pp. 641-52. Elsevier, Amsterdam, The Netherlands. Shioda, K., Igarashi, M.A. & Kittaka, J. (1997) Control of water quality in the cultureof early-stage phyllosomas of Panulirus japonicus. Bull. Mar. Sci., 61, 177-89. Shojima, Y. (1963) Scyllarid phyllosoma’s habit of accompanying jellyfish. Bull. Jpn. Soc. Sci. Fish., 29, 349-53. Silberbauer, B.I. (1971) The biology of the South African rock lobster Jasus lalandii (H. Milne Edwards). I. Development. S. Afr. Div. Sea Fish. Invest. Rep., 92, 1-70. Takahashi, M. & Saisho, T. (1978) The complete larval development of the scyllarid lobster, Zbacus ciliatus (von Siebold) and Zbacus novem-dentatus (Gibbies) in the laboratory. Mem. Fac. Fish. Kagoshima Univ., 27, 305-53. Takahashi, Y., Nishida, S . & Kittaka, J. (1994) Existence of a fat body in the hemocoel of the puerulus stage of the red rock lobster Jasus edwardsii (Decapoda, Crustacea). Crustaceana, 66, 62-70. Thomas, L. (1963) Phyllosoma larvae associated with medusae. Nature, 198, 208. Tong, L.J., Moss, G.A., Paewai, M.M. & Pickering, T.D. (1997) Effect of brine-shrimp numbers on growth and survival of early-stage phyllosoma larvae of the rock lobster Jusus edwardsii. Mar. Freshwat. Res., 48, 93540. Wolfe, S.H. & Felgenhauer, B.E. (1991) Mouthpart and foregut ontogeny in larval, postlarval, and juvenile spiny lobster, Panulirus argus Latreille (Decapoda, Palinuridae). Zool. Scripla, 20, 5775. Yamakawa, T., Nishimura, M., Matsuda, H., Tsujigado, A. & Kamiya, N. (1989) Complete larval rearing of the Japanese spiny lobster Panulirus japonicus. Nippon Suisan Gakkaishi, 55, 745.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 29

Water Quality and Microflora in the Culture Water of Phyllosomas M.A. IGARASHI

Department of Fisheries Engineering, University of Cearrj, Fortuleza-

CE. Brazil

J. KITTAKA

Research Institute for Marine Biological Science, Research Institutes for

Science and TechnoIogy, The Science University of Tokyo, Nemuro City, Fisheries Reseurch Institute. Hokkaido 087-0166, Japan

29.1

Introduction

Since 1984, J. Kittaka has expedited his efforts towards the development of methods for phyllosoma culture of spiny lobster. He confirmed the importance of using microalgae in the phyllosoma culture water was confirmed for the first time in 1986. He observed that the early-stage phyllosomas of Panulirus japonicus succeeded in prolonging their lives for 1 month in culture water containing the microalgae Nannochloropsis oculata changed every day in 100 ml glass containers, while the phyllosomas survived for only a few days in the culture water without N . oculata (Kittaka, unpubl. data) The capacity of the culture container was then scaled up to a 100-litre cylindrical container with an upwelling system. Upon pressing out the juice of the mussel Mytilus edulis on the surface of the culture water, the third and fourth instars of the phyllosomas of Jusus edwardsii swam up to the surface of the culture water. The phyllosomas of J. edwardsii succeeded in prolonging their lives for approximately 2 months by feeding on M . edulis in the unchanged culture water with N . oculata. After exchange at approximately 50% of the water volume, mortality occurred, presumably owing to the abrupt increase in total viable counts of bacteria and a change in the culture water to an unsuitable bacterial composition associated with the decrease in the number of microalgal cells (Kittaka, unpubl. data). These facts suggest that the water quality of the culture water was maintained in a good condition for the phyllosomas by propagation of the microalgae. Phyllosomas of spiny lobster have a long and complex larval development. They go through many instars before they metamorphose into the puerulus stage. Culturing phyllosomas in the laboratory is proving to be very difficult, although several species of palinurid have been raised to the settlement stage (Kittaka, 1988; Kittaka et al., 1988; Kittaka & Ikegami, 1988; Yamakawa el al., 1989; Kittaka & Kimura, 1989). Efforts with those species have continued and the most successful culture species was the green rock lobster Jams verreauxi, with about 10% survival of phyllosomas to the puerulus stage (Kittaka et al., 1997). Integrated phyllosoma culture methods were characterized by combination of three principal factors:

533

534 Spiny Lobsters: Fisheries and Culture 0 0 0

providing good water circulation in the culture tanks in order to maintain the suspension and even distribution of both the phyllosomas and their foods growing phyllosomas in a microalgae culture in order to maintain water quality and microflora feeding with mussels M . edulis, in order to supply essential nutritional requirements for the phyllosomas.

Nannochloropsis oculata have been widely used in phyllosoma culture because this microalga grows at high concentrations for a relatively long period and contributes significantly to improving water quality. However, N . oculata produces organic materials, which result in both water quality deterioration and the occurrence of harmful bacteria. Thus, the period needed between changes of the culture water was studied with the early-stage phyllosomas of P . japonicus to alleviate the problem of water quality deterioration (Shioda et al., 1997). Recently, the use of coral sand filters has been studied as an alternative to water quality control in phyllosoma culture (Kittaka et al., unpubl. data). This chapter examines the changes in the water quality and microflora of the culture water which control the growth and survival rate of the phyllosomas.

29.2

Water quality management

According to Kittaka (1997), the change in feeding of the phyllosomas from living Artemia nauplii to non-living mussel ovary apparently increases the risk of contamination of culture water. Fouling organisms are the eventual cause of larval mortality. These commonly include the ciliata Vorticella spp., fungi Saprolegnia spp., benthic diatoms Navicula spp. and filamentous bacterium Leucothrix sp. These fouling organisms can attach themselves to the body surface of the early instars of phyllosoma. The fouling can seriously damage phyllosomas after the normal intermoult period has elapsed (Kittaka, 1997). Treatment with 1 x formaldehyde and 10 ppm streptomycin sulphate was shown to be an effective remedy in controlling Vorticella spp. (Matsuda et al., 1987) and Leucothrix sp. (Nishimura & Kamiya, 1985), respectively. Kittaka (1997) reported that an unknown shell disease was observed in a culture tank with a filter system for J. verreauxi phyllosomas (see Section 29.2.3), beginning about 100 days after hatching. Treatment of diseased phyllosomas with antibiotics or formaldehyde was not effective. The mortality decreased after removal of the filter system and supply of the cultured N . oculata but continued until the final instar (Kittaka, 1997). Shioda et al. (1997) showed the importance of the use of cultured N . oculata at the growth phase before ageing for controlling the culture water. The culture water of P . japonicus phyllosoma was changed on average every 83.5 days in 1987 (group D); 18.3 days with an initial 34 days in 1990 (group C) and 13.8 and 13.2 days for two groups (groups A and B), respectively, in 1991 (Table 29.1). The survival rate was

Water Quality and Microflora in the Culture Water of Phyllosomas

535

very poor in 1987 and slightly better in 1990. The highest survival rate was shown in 1991, in accordance with shortening water change intervals (Fig. 29.1).

29.2.1.

Microalgae

Because the spiny lobster larval life lasts for about 1 year, the microalgae are required to propagate all year round. The question of which species is most suitable for this purpose depends on its physiological and ecological characteristics. Inoculation of culture water with diatoms can be effective in controlling water quality during the rearing of larval stages of Penaeusjaponicus (Hudinaga & Kittaka, 1967). However, the growth period for diatoms is rather short. Wickins (1972) found that prawn larval growth and development were improved by the presence of microalgae, and Jones (1970) showed an improvement in growth and survival for 40 species of fish in the presence of Chlorella. The microalga N . oculata has been used in Japan in artificial rearing of marine fish and shrimp because of its water quality controlling activity (Fujita, 1979; Hirata, 1979; Oda & Yamanoi, 1982), and growth and survival of phyllosomas were significantly better in the culture with N . oculata (Kittaka, 1994). In a culture system, ammonia-N occurs in water from two sources, the ammonification of unconsumed foods by heterotrophic bacteria, and transamination of catabolic products of organic nitrogen ingested and assimilated by cultured animals (Armstrong, 1979). These substances may stimulate the growth of microalgae such as N . oculata with a reduction in the ammonia-N level. However, immediate removal of excreted inorganic nutrients by phytoplankton (natural samples: Chaetoceros sp., Thalassiosira sp. and Eucampia sp.; cultured samples: Nitzschia delicatissima and Skeletonema costatum) cultured with zooplankton (Euphasia pacijica and Metridia pacijka) has been shown (Takahashi & Ikeda, Table 29.1 Characteristics of the phyllosoma culture water for Panulirus japonicus Year and group"

Phyllosomas cultured

(4

Days using culture medium (days)

Initial concentration of Nannochloropsis (lo6 ceIIs/ml)

Daily % concentration increase

1987 D 1990 C 1991 A 1991 B 1991 (total)

2 7 12 10 40b

83.5 18.3 13.8 13.2 13.9

15.28 f 1.08 0.34 f 0.23 0.96 rt 0.39 1.12 f 0.64 1.19 f 0.48

0.4 64.9 47.6 33.5 16.7

f 24.5

rt 9.4 f 1.6 f 1.8

f 3.0

f 0.4

f 41.6 f 112.1 f 34.2 f 11.5

From Shioda et al. (1997). "Hatching dates: A, 17 July 1991; B, 18 July 1991; C, 12 July 1990; D, 18 July 1987. b18 cultures of mixture of groups A and B.

536 Spiny Lobsters: Fisheries and Culture

0

50

100

150

200

Days Fig. 29.1 Survival rate of phyllosomas of Punulirus juponicus in 1987 (group D), 1990 (group C) and 1991 (groups A and B). Hatching dates: A, 17 July 1991; B, 18 July 1991; C , 12 July 1990; D, 18 July 1987. From Shioda er ul. (1997).

1975). Diatoms can utilize organic nitrogenous substances such as peptone, trypticase, urea and several kinds of amino acids (Yamada et al., 1983). Hanaoka (1977) showed that ammonia accumulated in a closed system of cultivation is absorbed by Chlorella, i.e. nutrient recycling in the tank was carried out by Chlorella. Nannochloropsis culture

The N . oculata was grown outdoors or indoors. For the nutrient medium, ammonium sulfate, calcium dihydrogen phosphate and urea were added at 100, 10 and 30 ppm, respectively. Cell numbers of N . oculata, ammonia-N and chemical oxygen demand (COD) of the culture water were measured from the beginning of the culture for about 300 days by Shioda et al. (1997). After about 60 days, the N . oculata cell number reached a peak, and then decreased slightly to 50 x lo6 cells/ml. Consequently, COD increased from 1 to 9 ppm while ammonia-N decreased from 22 to 6 ppm during the initial 70 days, and then gradually decreased to 1 ppm. These

Water Quality and Microflora in the Culture Water of Phyllosomas

537

results suggest the importance of inoculation in the phyllosoma culture water with N . oculata cultured for about 60 days, because stock of newly cultured N . oculata can contain a high concentration of ammonia-N.

Nannochloropsis in phyllosoma culture water To control contamination problems associated with feeding mussel gonad, mass subcultures of N . oculata of about 50 x lo6 cells/ml were introduced into the phyllosoma culture water to give an initial concentration of about 2 x lo6 cells/ml (Kittaka, 1988; Kittaka & Ikegami, 1988; Kittaka et al., 1988, 1997; Kittaka & Kimura, 1989). The N . oculata cell number increased rapidly for a period of about 10 days, followed by stable cell numbers for several days and then a decrease, as shown in Fig. 29.2 (for group A in 1991; Fig. 29.1), Fig. 29.3 (for group B in 1991; Fig.29.1) and Fig. 29.4 (for group C in 1990; Fig. 29.1) (Shioda et al., 1997). The percentage of average daily increase of N . oculata cells was 14.0 and 19.5% at the initial cell number of 1.22 x 106/mlfor groups A and B, respectively. A higher daily percentage increase of 22.0% occurred with the lowest initial cell number at 0.9 x 1O6/m1for group C, while the lowest daily percentage increase of 0.4% occurred with the highest initial cell number at 15 x 106/ml for group D in 1987 (Table 29.1).

Carotenoid/chlorophyN a ratio Phyllosoma culture water was light green just after the introduction of N . oculata. Measurement of chlorophyll is well documented by Strickland & Parsons (1968) and Jeffrey & Humphery (1975). The quantity of chlorophyll contained within cells is dependent on the physiological state of the microalgae (Austin, 1988). Chlorophyll a, b and c and total carotenoids of N . oculata in the phyllosoma culture water were extracted with 90% acetone from 1 litre of culture water after concentration on a membrane filter. The quantity of pigment was then determined spectrophotometrically at 663, 645 and 630 nm for chlorophyll a, b and c, respectively, and at 480 nm for carotenoids. The green colour gradually deepened, and then changed to a range of yellows. The relation between colour and Cd/Ca (carotenoid/chlorophyll a ) of the phyllosoma culture water is shown in Table 29.2 (Shioda et al., 1997). Only the ratio of carotenoids and chlorophyll a was calculated because chlorophyll b and c were much lower than chlorophyll a. A change in colour of the phyllosoma culture water from green to yellow occurred with consumption of ammonia-N along with the increase of carotenoids rather than chlorophylls. The Cd/ Ca ratio in the phyllosoma culture was initially 0.30 and increased to 0.50 over about 2 weeks. Green colour dominated at the lower Cd/Ca ratios ( ~ 0 . 3 3 )and yellow colour at the higher Cd/Ca ratios( > 0.42) (Shioda et al., 1997).

538 Spiny Lobsters: Fisheries and Culture r

0

50

100

150

Days Fig. 29.2 Growth of Nannochloropsis oculata with carotenoids and chlorophyll a ratio and change in chemical oxygen demand (COD) and ammonia-N concentration in culture water of phyllosomas of Panulirusjaponicus hatched on 17 July 1991 (group A) with total amount of food supply. Dotted lines indicate that measurements were made at the beginning and the end of the cultures. From Shioda et al. (1997).

29.2.2

Water quality parameters

Water temperature

Water temperature affects phyllosoma growth, and various species of spiny lobster require different temperature ranges. Water temperature was maintained at around 20°C for the cool-temperate Jasus spp. and Pulinurus elephas, and at around 25°C for the subtropical species P . juponicus (Kittaka, 1994). The temperature of the culture water was controlled by means of both heaters and coolers in combination.

Water Quality and Microjiora in the Culture Water of Phyllosomas

0

50

100

539

150

Days Fig. 29.3 Growth of Nannochloropsis oculata with carotenoids and chlorophyll a ratio and change in chemical oxygen demand (COD) and ammonia-N concentration in culture water of phyllosomas of Panulirusjaponicus hatched on 18 July 1991 (group B) with total amount of food supply. Dotted lines indicate that measurements were made at the beginning and the end of the cultures. From Shioda et al. (1997).

Temperatures fluctuated within a range f 1 ST.No special effect was observed on the behaviour of the phyllosomas under these temperature conditions (Kittaka, 1994). Salinity

Salinity is one of the most basic parameters of the culture environment for phyllosomas. The salinity in the oceans is generally between 33 and 37%0 (Sverdrup et al., 1942). Ambient seawater with salinity fluctuating between 35.5 and 33.5%0 has

540 Spiny Lobsters: Fisheries and Culture

---- Nannochloropsis TetraselrnisSP.

8-

4-

20 lo

F j f i-a/-/-/P

0

----

I'

.-b

SP.

Myti/us edulis Artemia nauplius

0

8-

20

0-

0

r

I0.4

a 0

100

50

0

150

Days Fig. 29.4 Growth of Nannochloropsis oculata and change in chemical oxygen demand (COD) and ammonia-N concentration in culture water of Panulirus japonicus hatched on 12 July 1990 (group C) with total amount of food supply. Dotted lines indicate that measurements were made at the beginning and the end of the cultures. From Shioda et al. (1997). Table 29.2 Relation between colour and concentration of Nannochloropsis oculata and chemical oxygen demand (COD) and ratio of total carotenoids/chlorophyll a (Cd/Ca) in phyllosoma culture water of Panulirus japonicus

Coloura

Culture no.

Nannochloropsis ( 1o6 cells/mI)

COD (PP4

Cd/Ca

G1 G2 G3 Y1 Y2 Y3

17 29 11 9 10 1

1.43 2.38 3.74 3.58 3.13 4.71

0.60 0.77 0.86 0.89 1.00 ND

0.311 f 0.027 0.317 f 0.038 0.338 f 0.043 0.424 f 0.009 0.451 f 0.072 0.54

~

f 0.96

f 1.20

1.66 1.35 f 1.62 f f

f 0.20

0.26 f 0.15 f 0.14 f 0.16 f

From Shioda et al. (1997). aG1, light green; G2, medium green; G3, deep green; Y1, light yellow and G3, Y1; Y2, medium yellow and G3, Y2; Y3, deep yellow and G3, Y3. ND, not detectable.

Water Quality and Microflora in the Culture Water of Phyllosomas

541

been supplied in the culture tank.However, salinity increased due to evaporation of the culture water caused by the heaters in winter. High salinity was adjusted by the addition of ion-exchange water, which caused a lowering of 1.0-1.5%0.No significant effect was observed on inducing moult for phyllosomas due to sudden changes in salinity (Kittaka, 1994).

PH Although the optimum pH for phyllosomas has not yet been determined experimentally, it is apparent that the pH value found in the ocean will be suitable for phyllosoma culture. The phytoplankton culture keeps the pH in larval culture water within the suitable range for decapoda crustaceans (Cohen et al., 1976). The pH of phyllosoma culture water during the growth phase of microalgae fluctuated diurnally within a relatively wide range between 8.0 and 8.6 (Kittaka, 1994). The most serious effect of pH is associated with the ammonia-N content of the water. Ammonia in water can be either ionized (NH4+) or non-ionized (NH3), i.e. ammonia = NH3 + NH4+. If the pH value is high, this signifies increased levels of non-ionized ammonia (NH3), which is the toxic component of ammonia. No effect of ammonia toxicity linked to pH was obseved in phyllosomas in culture experiments using microalgae (Kittaka, 1994).

Ammonia- N Ammonia-N is the most common toxicant in aquaculture systems. Accumulation of ammonia and its toxicity are of fundamental concern in phyllosoma culture. The initial ammonia-N was probably produced from the residue of nutrients (ammonium sulphate and urea) in the N . oculata culture water introduced into the phyllosoma culture water. Another source of ammonia-N is through excretion by the phyllosoma. According to Shioda et al. (1997) the ammonia-N level in the phyllosoma culture water declined rapidly during the N . oculata growth phase (Fig. 29.2- 29.4). The initial concentration of ammonia was <0.4 mg/l when cultured N . oculata were inoculated into the phyllosoma culture water (5-10% of the total volume of the phyllosoma culture water). In many cultures, ammonia-N decreased to a negligible amount within a few days while there was less increase in the number of cells of N . oculata; ammonia-N increased gradually to a maximum of 1.4 mg/l. In this case the toxic non-ionized ammonia-N was calculated at a concentration equivalent to 0.084 mg/l. No effects on growth and food consumption were observed in the phyllosomas at this ammonia concentration. The phyllosoma culture water was exchanged at around this level, because of an associated increase in organic materials, measured as COD (Kittaka, 1994). The median lethal dose (LDS0)of ammonia-N for a 72-h period was 8 mg/l for the 13th to 15th instar of P. japonicus (Kittaka, 1994).

542 Spiny Lobsters: Fisheries and Culture Chemical oxygen demand

Chemical oxygen demand (COD) is considered an indicator of accumulated organic material, and in due course as an indicator of culture water quality. COD was measured by the alkaline method using potassium permanganate as the oxidizing agent (Japanese Industrial Standards Committee, 1933). The initial value of COD in the phyllosoma culture water was 0.2-0.6 ppm, which was caused by the introduction of N . oculata. According to Shioda et al. (1997), analyses of P . japonicus phyllosoma culture water indicated that COD increased with time. Maxima were 1.2 and 1.5 ppm after 14 and 19 days in culture groups A (Fig.29.2) and B in 1991 (Fig. 29.3), respectively, and 1.4 ppm after 15 days of culture for group C in 1990 (Fig. 29.4). However, the increase was not influenced by the mussel pieces fed to the phyllosomas (Kittaka, 1994). The daily percentage increase in N . oculata cell numbers for groups A and B was calculated from the total percentage increase divided by the number of days during each time interval. The data were subdivided into two groups based on the daily percentage increase; the low growth group had daily percentage increase values above the median (Shioda et al., 1997). There was no significant relationship between the number of mussel pieces fed and COD for all data ( F = 1.221, p = 0.280, n = 27) for the high growth group of N . oculata ( F = 0.036, p = 0.854, n = 11) or for the low growth group of N . oculata (F = 0.847, p = 0.379, n = 12), as shown in Figs. 29.5 and 29.6, respectively.

Pieces of mussel gonad fed daily Fig. 29.5 Relation between pieces of mussel gonad fed and daily increase in chemical oxygen demand (COD) in the phyllosoma culture water for Panulirus japonicus in 1991 (groups A and B). 0: low-growth group for Nannochloropsis oculata; 0: high-growth group for Nannochloropsis oculata. From Shioda et al. (1997).

Water Quality and Microfora in the Culture Water of Phyllosomas

543

0

h

a

0.08

Y

3

3

0.06-

.-c .-

0.04-

Q)

0

m

U

n

8

0.02-

0.00 ! 0

0

0

0

I

I

I

I

I

10

20

30

40

50

60

Nannochloropsis sp. daily increase (%) Fig. 29.6 Relation between daily percentage increase in Nannochloropsis oculata and daily increase in chemical oxygen demand (COD) in the phyllosoma culture water for Panulirus japonicus in 1991 (groups A and B). From Shioda et al. (1997).

The origin of COD is believed to be mainly through the decomposition of dead algae (Parsons et al., 1973) and the release of photosynthetic products by algae (Fogg, 1966). The results shown in Figs. 29.5 and 29.6 demonstrate a negative relationship between COD increase and the daily percentage increase of N . oculata. This is evidence of the purification activity by microalgae on water quality. The relationship was expressed as the following formula: COD daily increase (mg/l) = 0.06364000853 x (daily YOincrease in N . oculata) ( F = 7 . 1 8 3 , ~= 0.014, n = 23; r2 = 0.2549). According to Kittaka (1994), the survival of J. verreauxi phyllosoma was significantly lower after midstage when they were exposed to relatively high COD at 3.8 mg/l at the early stage, while successful culture of pueruli has been achieved in large numbers for J. verreauxi (Kittaka et a1.,1997). In the latter case, COD showed an increase to 1.9 mg/l. Analysis of phyllosoma culture water indicated an allowable upper limit for water quality of 1.2 mg/l COD for J. verreauxi and P.japonicus, which was the COD value normally occurring after about 2 weeks of phyllosoma culture (Kittaka, 1997). However, substances measured as COD have not yet been completely determined. Therefore, 1.2 mg/l COD may be the standard for phyllosoma culture with N. oculata. The COD value may be changeable depending on the culture method. Heavy metals

The presence of high levels of heavy metals in the water was shown to be harmful and may cause mortality. The toxicity of heavy metals is related primarily to the

544 Spiny Lobsters: Fisheries and Culture dissolved, ionic form of the metal, e.g. Cu2+ or Zn2+, rather than to adsorbed, chelated or complexed forms (Boyd, 1989). Thus, culturists should avoid sites that may be contaminated with heavy metals from the facilities and equipment used. According to Kittaka’s (1994) analysis of phyllosoma culture water in the laboratory at Sanriku, the copper concentration was at levels of 0.0043 mg/l for ambient seawater, 0.03-0.05 mg/l for filtered and sterilized seawater, and 0.04-0.06 mg/l for the phyllosoma culture water. Zinc levels rose from 0.002-0.03 mg/l for filtered and sterilized seawater to 0.02-0.05 mg/l for the phyllosoma culture water. The LDS0 over about a 24-h period was determined as 0.3 mg/l of cooper and 6 mg/l of zinc for midstage phyllosomas of P . japonicus (Kittaka, 1994).

29.2.3

Recirculating culture system with a coral sand filter

In the phyllosoma culture using the microalga N . oculata, accumulation of microalgae during the declining phase may cause deterioration of water quality which results in difficulty in controlling microflora. A new culture system has been tried, with the introduction of a biological filter with coral sand. The coral sand filter decreased the concentration of ammonia-N in the water. The concentration of ammonia was measured at <25 pg/l. A bacterial film was reduced on the wall and bottom of the culture tank (see Section 29.3). These facts suggest that the coral sand filter could not only removed ammonia-N but also produced better water quality. While COD varied, and was at a relatively high level between 1.4 and 1.8 mg/l, this may be a characteristic of the water quality produced from a coral sand filter system. The coral sand filter may constitute a good alternative to microalga for the maintenance of microflora.

29.3

Microflora

The microflora in the culture water of palinurids was analysed by Igarashi et al. (1990, 1991, 1999 and unpubl. data). Production of phyllosomas is often limited by water quality degradation, and elevated numbers of bacteria may occasionally cause disease or mortality among cultured phyllosoma. Microalgae are believed to play important roles in the maintenance of microflora for water quality control. Culture experiments showed that presumably N . oculata produce the inhibitory substance for cell growth to certain species of bacteria. The first recognition that plants produce selective inhibitory substances may be Pasteur’s observation in 1857 (Burkholder et al., 1960). Katayama (1962) reported that seaweeds show antibacterial properties. Sieburth (1968) showed that the abundance of bacteria on seaweeds varies seasonally, showing a reduction in numbers during growth periods of the algae. Phytoplankton may release substances inhibitory to bacterial growth (Cole, 1982). Maximal antibiosis was shown by Roos (1957) to occur during periods of active algal

Water Quality and Microjlora in the Culture Water of Phyllosomas

545

growth. Rheinheimer (1971) reported that vigorously growing algae are usually free from bacteria on their surface, and while the phytoplankton bloom is building up, bacteria occur in very small numbers. Although the significance of microalgae in the phyllosoma culture water is not yet fully understood (Kittaka, 1997), it is well known that cultured penaeid shrimps are less susceptible to bacterial or viral disease in a pond with a stable growth of diatoms (e.g. Limsuwan, 1992). According to Lewis et al. (1988) the maintenance of stable bacterial numbers is due partly to the log-phase state of microalgal growth. Some species of microalgae such as marine Chlorella inhibit the development of contaminants in dense cultures (Spektorova et al., 1986), while several workers (Mayer et al., 1964; Blasco, 1965; Vela & Guerra, 1966) reported that in general most pathogens do not survive well in Chlorella cultures. The first antibiotic to be isolated from an autotroph (Chlorella) was effective against both Gram-positive and Gramnegative bacteria including Staphyllococcus aureus, Streptococcus pyogenes, Bacillus subtilis and Pseudomonas aeruginosa (Pratt et al., 1944). The present authors showed that in the phyllosoma culture water, in general most bacteria which form yellow, orange and swarming colonies do not survive well at the initial phase of N . oculata culture. Hameed (1993) related that the addition of mixed phytoplankton into the tank water, as a feed for the penaeid larvae, might suppress bacteria, especially Vibrio sp. in water and larvae. Such a conclusion was also reported by Bell et al. (1974), Jolley & Jones (1974) and Kogure et al. (1979).

29.3.1

Bacteria in Nannochloropsis culture

The concentration of bacteria in N . oculata culture water ranged from 1.2 x lo3 to 2.8 x lo5 and 4.5 x lo2 to 1.4 x lo5 CFU/ml (CFU = colony-forming units on ZoBell's 22 16E agar medium inoculated aerobically at 20°C for 2 days), respectively, with bacteria which form pale white and white colonies exclusively (Igarashi et al., 1990, 1991 and unpubl. data).

29.3.2

Bacteria in phyllosoma culture

Bacterial number and microflora for group A in 1991 and for group C in 1990 are shown in Figs. 29.7 and 29.8 (Igarashi et al., 1990, 1991). The initial bacterial count was 10' CFU/ml, which increased rapidly to 103-104 CFU/ml after 1-3 days, and then the bacterial number decreased to lo3 CFU/ml. The bacterial number ranged between 4 x lo3 and 3 x lo4, with an average of 1.37 x lo4 CFU/ml for group A in 1991, and 5 x lo2 and 9 x lo4, with an average 1.74 x lo4, for group C in 1990. The percentage of pale white and white colony forming bacteria ranged from 12.0 to 67.5% (average 43.4%) and from 12.0 to 54.5% (average: 33.6%) for group A, and ranged from 10.0 to 84.5% (average

546 Spiny Lobsters: Fisheries and Culture

-.-m 1 L

Days Fig. 29.7 Colony characteristics and total bacterial counts in culture water of phyllosomas for Panulirus japonicus in 1991 (group A). From Shioda et al. (1997).

47.8%) and from 11.0 to 75.0% (average 33.5%) for group C,respectively. Other bacterial strains, swarming, yellow and orange colony-forming bacteria, averaged 18.0, 3.5 and 0 % for Group A, and 14.0, 4.9 and 0 % for Group C, respectively. Better survival rate was shown for group A than for group C . The culture water was changed after a shorter interval for group A than for group C . The phyllosoma culture water with N . oculutu occasionally changed from green to turbid white, and eventually became transparent. In green water phyllosomas were very active and the bacterial number was significantly low compared with the

Water Quality and Microjlora in the Culture Water of Phyllosomas

547

106-

102

1

I

I

I

I

I

I

I

Days Fig. 29.8 Colony characteristics and total bacterial counts in culture water of phyllosomas for Panulirusjaponicus in 1990 (group C). From Shioda et al. (1997).

bacterial population of turbid white in which phyllosoma were inactive. The phyllosomas recovered their activity in transparent water. It is likely that N . oculata controls bacterial propagation. In green water, Pseudomonas was the most dominant genus. Aeromonas and Cytophaga-Flexibacter increased in turbid white water. In the transparent water Vibrio became the predominant bacterial group (Table 29.3) (Igarashi et al., 1990).

548 Spiny Lobsters: Fisheries and Culture Table 29.3 Change of microflora in phyllosoma culture water with Nannochloropsis sp. Viable countsa Genus

Green waterb

Turbid white water'

Vibrio Aeromonas Pseudomonas Moraxella Cytophagu-Flexibacfer Staphylococcus Micrococcus Acinetobacter TVC

1.0 x 6.0 x 4.4 x 8.0 x 1 .O x ND ND ND 6.0 x

10' (1.5) 10' (10.0) lo2 (73.5) 10' (13.5) 10' (1.5)

5.0 x 7.5 x 1.3 x 3.7 x 1.8 x 5.0 x 5.0 x 5.0 x

lo2

2.8

10' (1.5) lo2 (26.5) lo3 (46.5) lo2 (13.5) lo2 (7.5) 10' (1.5) 10' (1.5) 10' (1.5) lo3

Transparent waterd 4.0 x 4.0 x 4.0 x 1.0 x NDe ND ND ND 4.9 x

lo3 (81.5) lo2 (8.5) lo2 (8.5) lo2 (1.5)

lo3

aColony-forming units (CFU/ml): numbers in parentheses indicate percentage. bCulture of Nannochloropsis sp. 'About 15 days after beginning phyllosoma culture. dAbout 30 days after beginning phyllosoma culture. ND, not detected; TVC, total viable count (CFUlml).

29.3.3

Effect of microflora on phyllosomas

In some cases, phyllosoma culture of P . japonicus showed good results, with a survival rate of 90% up to about 90 days. In this case, total viable counts of bacteria in the culture water ranged from 6 x lo3 and 9 x lo4 with an average of 3.1 x lo4 CFU/ml. The percentage of pale white colony-forming bacteria (mainly Pseudomonus spp.) and white colony-forming bacteria (mainly Vibrio spp.) ranged from 8 to 78% (average 47%) and from 22 to 54% (average 35%), respectively. The activities of phyllosomas were enhanced by the elevated percentage of bacteria which form pale white and white colonies. The percentage of other bacterial strains, swarming, yellow and orange colony-forming bacteria, ranged from 0 to 39% (average 11.3%), 0 to 13% (average 2.6%), and 0 to 22% (average 2.4%), respectively. When swarming colony-forming bacteria occurred, less feeding activity was observed for the phyllosomas of J . edwardsii (Kittaka, 1994). Swarming bacteria can be considered as an indicator of poor water quality. The genera Pseudomonas and Vibrio which were isolated from green and transparent culture water, respectively, were grown in mass culture in ZoBell's 2216 E liquid medium at 20°C for 2 days. The cultured bacteria were added to the J . edwardsii phyllosoma culture water, separately, at a concentration of lo5-] O6 CFU/ ml. The bacterial number decreased to 102-103 CFU/ml after several days and became stable (Igarashi et al., 1990). The phyllosoma culture water was renewed and cultured bacteria were inoculated at intervals of about 10 days. The microflora was composed of bacteria which produce pale white and white pigment, exclusively.

Water Quality and Microflora in the Culture Water of Phyllosomas

549

Bacteria which form yellow, orange and swarming colonies were not detected in 100 days of culture. This suggests that yellow, orange and swarming colony-forming bacteria were repressed by bacteria such as Pseudomonas sp. and Vibrio sp. (Table 29.4), which can probably control certain bacterial proliferations. The survival rate was between 100 and 90% and moult frequency (average number of moults per individual for 48-day period) was 2.8 and 2.2 for the tanks inoculated with Pseudomonas sp. and Vibrio sp., respectively. Phyllosomas showed good survival rates, although moult frequency was higher in the culture tank inoculated with N . oculata sp. (Table 29.5) (Igarashi et al., 1990). The culture water with Pseudomonas or Vibrio showed lower pH values of 7.827.89 compared with N . oculata with an average pH of 8.24. One factor which may affect the growth of phyllosoma may be the difference in pH of the culture water. Better control of pH will be necessary to permit the use of selected bacterial strains in phyllosoma culture water.

29.3.4

Bacteria in recirculating culture water through a filter system

The bacterial number in the culture water through a coral sand filter ranged between 6.0 x lo2 and 1.4 x lo5 with an average of 1.0 x lo3 CFU/ml. The pale white and white colony-forming bacteria averaged 64.5% (range 46.5-80.5) and 35.5% (range 19.5-53.5), respectively (Igarashi & Kittaka, unpubl. data). No yellow, orange or swarming colony-forming bacteria were detected. This is a characteristic of the recirculating system with a coral sand filter. However, as with pseudomembranous Table 29.4 Rearing conditions for Jaws edwardsii phyllossomas in the culture tank inoculated with marine bacteria Vibrio sp.

Pseudomonas sp.

Composition YO

Composition % Days 29 39 49 59 69 78 89 97

CFU/ml 6.9 8.5 2.1 8.3 1.5 2.2 1.0 4.6

x lo2 x 104 x lo4 x 103

103 lo4 x lo4 lo3

P

14.0 100.0 100.0 80.5 93.5 13.5 15.5 95.5

W

CFU/ml

26.0 0.0 0.0 19.5 6.5 26.5 24.5 4.5

1.3 x 3.2 x 6.6 x 8.2 x 1.4 x 6.9 x

lo3 lo2 lo3 lo2 lo2 lo3

P 86.5 100.0 97.0 72.0 64.5 72.5

W 13.5 0 3.0 28.0 35.5 27.5

CFU, colony-forming unit; P, Pale white colony-forming bacteria; W, White colony-forming bacteria.

550 Spiny Lobsters: Fisheries and Culture Table 29.5

Rearing results for Jasus edwardsii phyllosomas in media inoculated with bacteria Mortality"

Moult frequency

Davs

Pseudomonas

Vibrio

Controlb

Pseudomonas

Vibrio

Controlb

29-38 3948 49-58

0 0 0 0 0 0

0 0 2 0 1 3

0 1 0

6 19 24 21 13 83

4 22

23 33 23 18 13 110

5948 69-71 Total

0 0 1

14

13 12

65

"Initial number of phyllosomas: 30 per tank. bControl: phyllosomas were cultured with Nannochforopsissp.

colitis in humans, reduction in the diversity of the bacterial flora in the rotifers/ turbot culture ecosystem can result in unregulated growth of opportunistic pathogens (Larsen et al., 1978). In the case of J. verreauxi culture, growth of opportunistic pathogens occurred on the carapace of phyllosomas after about 200 days in culture (Kittaka et al., unpubl. data). The occurrence of shell disease signifies that the external surface of phyllosoma can be an ideal habitat for bacterial colonization. However, non-sterile culture with coral sand filter suffered the disadvantages that it may become contaminated with bacteria that can injure or kill the phyllosoma. The culture results in Nemuro (Hokkaido, north Japan) showed that a number of J . edwardsii phyllosomas died in the final stage (Kittaka 8z Onoda, unpubl. data). It is probable that in order to control opportunistic pathogens the development of a more stable number of bacteria and bacterial types is needed to ensure healthy phyllosomas. However, the health of phyllosomas is improved by the elimination of pathogens, or at least minimizing the effect of pathogens by improving water quality. These disease problems are considered to result from the interaction of microbes and their environment. Therefore, the author's culture practice suggests the use of both methods, with cultured Nannochloropsis and with a coral sand filter, alternatively and efficiently, in order to establish a better culture method for phyllosomas.

29.4

General considerations

At the new facility in Nemuro, swarming, yellow and orange colony-forming bacteria have been rare in the culture water compared with the old facility at Sanriku. This may be due to differences in water temperature and water quality between these sites and to improvements in the facilities and equipment at the new

Water Quality and Microflora in the Culture Water of Phyllosomas

551

site, although there is always a risk of contamination in the culture system and there is no way to exclude pathogenic microorganisms (Kittaka, 1997). In general, the phyllosoma culture water showed an increase in bacterial number after about 2 weeks. It is likely that dead cells of N . oculata in the culture water are decomposed by bacteria. This may suggest that rich nutrition in the phyllosoma culture system may have some influence on the total bacterial numbers as well on the patterns of generic composition of bacterial population. However, in general, living cells of N . oculata were not attacked by the bacterial population of the culture water. The presence of bacteria which form yellow, orange and swarming colonies is often indicative of an unsuitable environment. In addition, during the studies on Chlorella pyrenoidosa 71 105 by Sorokin & Myers (1953), a characteristic association was observed between poor algal growth and the presence of bacterial contaminants. It is clear that some of the organic matter from a dead cell will be metabolized by bacteria. Otherwise, water quality would be worsened owing to rapid fermentation of organic materials by bacteria, resulting in a poor survival rate of phyllosomas. These studies indicate the need for examination of productive aquatic habits for pathogenic organism that can grow by using algal organic matter. The effects of both microflora and accumulated substances on the survival of phyllosomas have not been fully analysed with the ageing N . oculata. However, culture practice has shown the importance of changing the culture water of phyllosomas of P . japonicus every 14 days before ageing of the cultured N . oculata, and every 20 days for phyllosoma of J. verreauxi. This is important to alleviate the problem of mortality in the phyllosoma culture. Experiments have also shown that J . verreauxi tolerates high bacterial levels and swarming bacteria in the culture water better than phyllosoma of P . japonicus. In the marine system, bacteria usually number near lo6 cells/ml, when counted by direct microscopic methods (Cole, 1982). However, the bacterial number in the culture water of Penaeusjaponicus larvae ranged from lo3 to lo6 CFU/ml (Igarashi et al., 1991). Yasuda & Kitao (1980) reported the maximum count of 1.8 x lo5 CFU/ml, while in the larval culture water of P . monodon it ranged from lo2 to lo5 CFU/ml (Llobrera & Gakutan, 1977) similar to the culture water of P . indicus larvae which ranged from 9.0 x lo2 to 1.0 x lo5 CFU/ml (Hameed, 1993). In the case of the homarid lobster Homarus americanus, the bacterial number was stable, ranging from 1.4 x lo5 to 8.8 x lo5 CFU/ml during 13 days of larval culture (Igarashi et al., 1991). Bacterial counts in the culture water of the Hanasaki king crab Paralithodes brevipes larvae ranged from lo3 to lo4 CFU/ml (Watanabe et al., 1998a), while in the culture water of red king crab Paralithodes camtschaticus the bacterial number was varied from 3.6 x lo3 to 1.8 x lo5 CFU/ml (Igarashi & Kittaka, unpubl. data). In the case of horse hair crab Erimacrus isenbeckii larvae the bacterial number was comparable with that of the red king crabs, ranging from 1.3 x lo4 to 8.0 x lo4 CFU/ml (Watanabe et al., 1998b). The effectiveness of using bacteria was demonstrated for penaeid larvae and portunid larvae by Maeda & Nogami (1989) and Maeda et al. (1991). Bacterial

552 Spiny Lobsters: Fisheries and Culture

strains which showed good results in larval growth of the prawn Penaeus monodon also promoted the growth of crab larvae, Portunus tridendatus. This bacterium and several other strains repressed the growth of Vibrio alginolyticus, a swarming bacterium, and several species of fungus (Maeda & Nogami, 1989). These data suggest that controlling the microflora of phyllosoma culture water using bacteria is possible, and the bacteria will keep the phyllosoma culture water in better condition, which will increase the production of phyllosoma. In general, the bacterial number in the culture water of phyllosomas ranged from lo3 to lo4 CFU/ml. In simulations of culture without phyllosoma, the bacterial number was higher at 103-105 CFU/ml in the water inoculted with N . oculata, compared with 102-104 CFU/ml in the recirculated water through a coral sand filter. Seasonal variations do not seem to alter these bacterial numbers. The quantitative flutuactions observed in the bacterial population in the culture water of crustacean larvae were probably related to differences in the culture method. In the phyllosoma culture, high bacterial growth has been rare, probably owing to hygienic practices such as feeding with washed M . edulis and removal of food remains before each feeding. In general, M . edulis was served to the phyllosomas twice per day; part of the feed remained uneaten for hours, during which time nutrients could leach out, but the feed did not disintegrate. Such procedures to remove food particles have not been used for homarid, penaeid and lithodid larvae. Observation of the bacterial population in the culture water indicates that the phyllosomas were more sensitive to the presence of bacteria, and the low bacterial number is very characteristic of good phyllosoma culture water. In addition, mortality is more frequent in palinurid than in homarid, penaeid and lithodid during the larval period, probably owing to the thin and soft exoskeleton of phyllosomas. Phyllosomas can be cultured successfully in small numbers without microalgae. In such cases, bacterial numbers were low, and pale white and white colony-forming bacteria predominated in the culture water. The inoculation of these bacterial strains can improve the survival rate of phyllosomas. This fact suggested that the culture water can be controlled microbiologically. It is suggested that phyllosoma culture on a large scale could be established if more attention were directed towards the design of a system that would assure excellent water quality via inoculation of selected bacterial strains and microalgae which can provide a suitable environment.However, bacteria will be found to be useful not only as food but also as biological controllers of fish disease and activators of the rate of nutrient regeneration (Yasuda & Taga, 1980). Phyllosomas are planktonic, requiring a culture system capable of producing currents to keep them suspended, separated and fed without physical injury. An important aspect of the phyllosoma culture system is a balanced, non-flutuating ecological system, which will favour phyllosoma growth and development. In order to establish such a balance, it is necessary to control the activity of each of the participating elements. The culture system for these phyllosomas must allow for the removal of waste and toxic metabolites. Frequent cleaning of tanks for the removal

Water Quality and Microjlora in the Culture Water of Phyllosomas

553

of wastes is not practical in commercial culture. The major desirable considerations in the phyllosoma culture system involve the maintenance of proper water quality through the self-purification potential of microalgae or bacteria. This offers a new perspective on successful commercial operations involving the culture of phyllosomas.

References Armstrong, D.A. (1979) Nitrogen toxicity to Crustacea and aspects of its dynamics in culture system. In 2nd Bienal Crustacean Health Workshop (Ed. by D. Lewis & J. Liang), pp. 329-60. Texas A&M, Sea Grant, TAMM-SE-79-114, Texas, USA. Austin, B. (1988) Microbiological Methods in Marine Microbiology, pp. 12-30. Cambridge University. Press, New York, USA. Bell, W.H., Lang, J.M. & Mitchell, R. (1974) Selective stimulation of marine bacteria by algal extracellular products. Lirnnol. Oceanogr., 19, 833-9. Blasco, R.J. (1965) Nature and role of bacterial contaminants in mass cultures of Chlorella pyrenoidosa. Appl. Microbiol., 13, 473-7. Boyd, C.E. (1989) Water quality management and aeration in shrimp farming. Fisheries and Allied Aquacultures Departmental Series No. 2, Alabama Agricultural Experiment Station, Auburn University, Auburn, AL, USA, 83 pp. Burkholder, P.P., Burkholder, L.M. 8t Almodovar, L. (1960) Antibiotic activity of some marine algae of Puerto Rico. Bot. Mar., 2, 149-56. Cohen, D., Finkel, A. & Sussman, M. (1976) On the role of algae in the larviculture of Macrobrachium rosenbergii. Aquaculture, 8, 199-207. Cole, J.J. (1982) Interactions between bacteria and algae in aquatic ecosystem. Annu. Rev. Ecol. Syst., 13, 291-314. Fogg, G.E. (1966) The extracellular products of algae. Oceanogr. Mar. Biol. Annu. Rev., 4, 195-212. Fujita, S. (1979) Culture of seabream, Pagrus major, and its food. In Cultivation ofFish Fry and its Live Food. Proc. Con$ Szymbark, Poland, 23-28 September 1977 (Ed. by E. StyczynskaJurewich, T.E. Jasper & G . Persoone). European Mariculture Society, Bredene, Belgium, Spec. h b l . , 4, 183-97. Hameed, ASS.( 1993) Study of the aerobic heterotrophic bacterial flora of hatchery-reared eggs, larvae and post-larvae of Penaeus indicus. Aquaculture, 117, 195-204. Hanaoka, H. (1977) Harmful effect of ammonia on growth of the brine shrimp Artemia salina and inhibition of ammonia accumulation with an alga Chlorella. Bull. Plankton Soc. Jpn, 24, 99-107. Hirata, H. (1979) Rotifer culture in Japan. In Cultivation ofFish Fry and its Live Food. Proc. Con$ Szymbark, Poland, 23-28 September 1977 (Ed. by E. Styczynska-Jurewich, T. Backiel, E. Jaspers & G. Persoone). European Mariculture Society, Bredene, Belgium, Spec. Publ., 4, 361-77. Hudinaga, M. & Kittaka, J. (1967) The large scale production of the young kuruma prawn, Penueus japonicus ate. Inform. Bull. Planktol. Jpn. Commemoration No. of Dr Matsue, 35-46. Igarashi, M.A., Kittaka, J. & Kawahara, E. (1990) Phyllosoma culture with inoculation of marine bacteria. Nippon Suisan Gakkaishi, 56, 1781-6. Igarashi, M.A., Romero, S.F. & Kittaka, J. (1991) Bacteriological character in the culture water of penaeid, homarid and palinurid larvae. Nippon Suisan Gakkaishi, 57, 2255-60.

554 Spiny Lobsters: Fisheries and Culture Jeffrey, S.W. & Humphrey, G.F. (1975) New spectrophotometric equations for determing chlorophylls a, b, cl and c2 in higher plants, algae and natural plankton. Biochem. Physiol. Pflanzen, 167, 1 9 1 4 Jolley, E.T. & Jones, A.K. (1974) The interaction between Navicula muralis Grunnow and an associated species of Flavobacterium. Br. Phycol. J., 12, 3 15-28. Jones, W.E. (1970) Chlorella for rearing of marine fish larvae. F A 0 Fish. Cult. Bull., 2, 3. Katayama, T. (1962) Volatile constituents. In Physiology and Biochemistry of Algae (Ed. by R.A. Lewin), pp. 467-73. Academic Press, New York, USA. Kittaka, J. (1988) Culture of the palinurid Jasus lalandii from egg stage to puerulus. Nippon Suisan Gakkaishi, 54, 87-93. Kittaka, J. (1994) Larval rearing. In Spiny Lobster Management (Ed. by B.F. Phillips, J.S. Cobb & J. Kittaka), pp. 402-23. Fishing News Books, Blackwell Scientific Publications, Oxford, UK. Kittaka, J.(1997) Culture of larval spiny lobster: a review of work done in northern Japan. Mar. Freshwater Res., 48, 923-30. Kittaka, J. & Ikegami, E. (1988) Culture of palinurid Palinurus elephas from egg stage to puerulus. Nippon Suisan Gakkaishi, 54, 1149-54. Kittaka, K. & Kimura, K. (1989) Culture of the Japanese spiny lobster Panulirus japonicus from egg to juvenile stage. Nippon Suisan Gakkaishi , 55, 963-70. Kittaka, J., Iwai, M. & Yoshimura, M. (1988) Culture of a hybrid of spiny lobster genus Jasus from egg stage to puerulus. Nippon Suisan Gakkaishi, 54, 413-17. Kittaka, J., Ono, K. & Booth, J.D. (1997) Complete development of the green rock lobster, Jasus verreauxi from egg to juvenile. Bull. Mar. Sci., 61(1), 57-71. Kogure, K., Simidu, U. & Taga, N. (1979) Effect of Skeletonema costatum (Grev.) Cleve on the growth of marine bacteria. J. Exp. Mar. Ecol, 36, 201-15. Larsen, H.E., Price, A.B., Honour, P. & Borriello, S.P. (1978) Clostridium d i f f i t e and the aetiology of pseudomembranous colitis. Lancef, i, 1063-6. Lewis, T.E., Garland, C.D., O'Brien, T.D., Fraser, M.I., Tong, P.A., Ward, C., Dix, T.G. & McMeekin, T.A. (1988) The use of 0.2 pm membrane-filtered seawater for improved control of bacteria level in microalgal cultures fed to larval Pacific oyster (Crassostrea gigas). Aquaculture, 69, 241-51. Limsuwan, C. (1992) Disease of black tiger shrimp, Penaeus monodon Fabricius in Thailand. Tech. Bull. Am. Soybean Assoc., pp. 1-15. Llobrera, A.T. & Gakutan, R.Q. (1977) Bacteria from seawater used in Penaeus monodon larval culture. Q. Res. Rep., Aquaculture Department, SEAFDEC, 1, 3840. Maeda, M. & Nogami, K. (1989) Some aspect of the biocontrolling method in aquaculture. In Current Topics in Marine Biotechnology (Ed. by S. Miyachi, I. Karube & Y. Ishida), pp. 395-8. Japanese Society for Marine Biotechnology, Tokyo, Japan. Maeda, M., Nogami, K. & Liao, I.C. (1991) Promotion of growth and prevention of disease of fish and shellfish using microorganism as biocontrol agents. In Microbiological Agents in Agriculture and Fisheries (Ed. by S . Egusa, H. Komada & H. Iwahama), pp. 178-93. CMC, Tokyo, Japan (in Japanese). Matsuda, H., Yamakawa, T., & Tsujigado, A. (1987) Larval production of slipper lobster. Annual Report, Mie Prejectural Fisheries Technological Centre, 1986, pp. 78-82 (in Japanese). Mayer, A.M., Zuri, U., Shain, Y & Ginzburg, H. (1964) Problems of design and ecological consideration in mass culture algae. Biotech. Bioeng., 6, 173-90. Nishimura, M. & Kamiya, N. (1985) Studies on larval production of Ise lobster. 111. Results of phyllosoma culture in 1983. Annual Report, Mie Prefectural Fisheries Technological Centre, 1983, pp. 1-6 (in Japanese). Oda, T. & Yamanoi, H. (1982) Mass culture of marine Chlorella sp. and rotifer Brachionusplicatilis. Proc. Fish. Inst., Okayama, 56, 233-5 (in Japanese).

Water Quality and Microjlora in the Culture Water of Phyllosomas

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Parsons, T.R., Takahashi, M. & Hargrave, B. (1973) Biological Oceanographic Processes. Pergamon Press, Oxford, UK. 332 pp. Pratt, R., Daniels, T.C., Eiler, J.J., Gunnison, J.B., Kumler, W.D., Oneto, J.F., Strait, L.A., Hardin, G.J., Milner, H.W., Smith, J.H.C. & Strain, H.H. (1944) Chlorellin: an antibiotic substance from Chlorella. Science, 99, 35 1-2. Rheinheimer, G. (1974) Microorganisms inhabiting plants and animals. In Aquatic Microbiology, pp. 107-17. Wiley, London, UK (trans. from German). Roos, H. (1957) Untersuchungen uber das Vorkommen antimicrobieller subtanzen in meeresalgen. Kieler Meeresforsch, 13, 41-58. Shioda, K., Igarashi, M.A. & Kittaka, J. (1997) Control of water quality in the culture of early stage phyllosoma of Panulirus japonicus. Bull. Mar. Sci., 61, 177-89. Sieburth, J.M. (1968) The influence of algal antibiosis on the ecology of marine microorganisms. In Microbiology of the Sea (Ed. by M.R. Droop & E.J. Ferguson Wood), pp. 63-94. Academic Press, New York, USA. Sorokin, C. & Myers, J. (1953) A high temperature strain of Chlorella. Science, 117, 33@1. Spektorova, L.V., Nosova, L.P., Goronva, O.I., Albistskaya, O.N. & Filippovskij, Yu. N. (1986) High-density culture of marine microalgae - promising items for mariculture 11. Determination of optimal light regime for Chlorella sp. F. Marine under high density culture conditions. Aquaculture, 55, 221-9. Strickland, J.D.H. & Parsons, T. R. (1968) A Practical Handbook of Seawater Analysis. Bulletin 167, Fisheries Research Board of Canada, Ottawa, Canada, 3 1 1 pp. Sverdrup, H.U., Johnson, M.W. & Fleming, R.H. (1942) The Oceans, Their Physics, Chemistry, and General Biology. Prentice-Hall, New York, 1087 pp. Takahashi, M. & Ikeda, T. (1975) Excretion of ammonia and inorganic phosphorus by Euphausia pacfica and Metridia pacifca at different concentrations of phytoplankton. J. Fish. Res. Board Can., 32, 2189-95. Vela, G.R. & Guerra, C.N. (1966) On the nature of mixed cultures of Chlorella pyrenoidosa and various bacteria. J . Gen. Microbiol., 42, 123-31. Watanabe, K., Fukunaga, T., Kamata, K., Sugisawa, T. & Yoshimizu, M. (1998a) Bacterial flora of hatchery-reared horsehair crab larvae. Bull. Fac. Fish. Hokkaido Univ., 49, 143-56. Watanabe, K., Takahashi, M., Kamata, K., Sugisawa, T. & Yoshimizu, M. (1998b) Bacteriological study on the mass mortality of cultured Hanasakicrab larvae-bacterial flora of cultured hanasakicrab larvae. Bull. Fac. Fish. Hokkaido Univ., 49, 59-69. Wickins, J.F. (1972) Experiments on the culture of the spot prawn Pandalus platyceros (Brandt) and the giant fresh water prawn Macrobrachiurn rosenbergii (de Man). Fish. Invest. Minist. Agric. Fish Food (G.B), Ser. 11, Salmon. Freshwat. Fish., 27, 23 pp. Yamada, M., Araki, Y., Tsuruta, A. & Yoshida, Y. (1983) Utilization of organic nitrogenous compounds as nitrogen source by marine phytoplancton. Bull. Jpn. SOC.Sci. Fish., 49, 1445-8. Yamakawa, T., Nishimura, M., Matsuda, H., Tsujigado, A. & Kamiya, N. (1989) Complete larval rearing of the Japanese spiny lobster Panulirus japonicus. Nippon Suisan Gakkaishi, 55, 745. Yasuda, K. & Kitao, T. (1980) Bacterial flora in the digestive tract of prawns, Penaeus japonicus BATE. Aquaculture, 19, 229-34. Yasuda, K & Taga, N.A. (I 980) A mass-culture method for Artemia salina using bacteria as food. La Mer, 18(2), 55-62.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 30

Spiny Lobster Growout J. D. BOOTH

National Institute of Water and Atmospheric Research, P.O. Box 14-901,

KiIbirnie, Wellington 6003, New Zealand

J. KITTAKA

Research Institute for Marine Biological Science, Research Institutes for

Science and Technology, The Science University of Tokyo, Nemuro City. Fisheries Research

lnst itute, Hokkaido 08 7-0166, Japan

30.1

Introduction

The high value of spiny lobsters continues to attract intense interest in the possibility of farming them. Aquaculture is one of only a few potential means of increasing yields, Spiny lobsters grown in captivity could fetch high prices through being the size that the market wants. To achieve this, detailed biological knowledge is required so that methods for economically growing juveniles can develop. Because of their different biology, not all ongrowing conditions for clawed lobsters are suitable for spiny lobsters. Aquaculture has been the world’s fastest growing food production system for more than a decade, with an average compound growth rate of 9.6% since 1984 (cf. 1.6% for capture fisheries production) (Tacon, 1998). However, spiny lobsters make up only a very small part of this, the 1995 production being only 69 t. This review of the aquaculture potential of spiny lobsters updates that of Booth & Kittaka (1994) and mainly addresses biological issues concerning the growout of juveniles. Some optimum ongrowing conditions for several species have now been broadly determined, lobster physiology has been more closely investigated since many lobsters are now delivered live to market, and some preliminary economic assessments have been made. Still, little work has been directed towards essential technical design for large-scale commercial production. Live spiny lobsters are sought in many parts of the world, particularly in Asia. Usually there are tight product specifications. One Japanese requirement, for example, is lively lobsters 200-300 g in weight, with sweet and crisp flesh and deep red external colour. Despite significant price premiums for such animals, this market is undersupplied. This is mainly because of the larger minimum legal size in most wild fisheries, and because no species is commercially cultivated on anything but a small scale. The puerulus, the settlement stage of spiny lobsters, resembles the juvenile in shape, and is 6-12 mm in carapace length (CL) in shallow-water species. It moults into the first juvenile instar (sometimes known as the first moult post-puerulus) a few days to a couple of weeks after settlement. The juvenile then takes many months according to species, sex and locality to reach marketable size. 556

Spiny Lobster Growout 30.2

557

Source of juveniles

Pueruli are not yet available commercially from hatcheries and so must come from the wild. They are taken on collectors along many shorelines in larval recruitment studies (Phillips & Booth, 1994), sometimes in high numbers. For example, about 30 000 Punulirus argus were captured around Antigua on collectors in 1 year (Lellis, 1990). Pueruli are also found on marine farms (e.g. Tholasilingam & Rangarajan, 1986) and under floating objects (Phillips & Booth, 1994). However, the only instances known to the authors where pueruli or small juveniles from the wild have been available for commercial ongrowing are in Taiwan, Singapore and India, where mainly small numbers of Punulirus spp. are ongrown in ponds or cages (Lee & Wickins, 1992; Chou & Lee, 1997), and in New Zealand. In New Zealand, smallscale experimental capture and sea-cage farming of Jusus edwardsii (Booth, 1992) have recently extended to larger enterprises where tens of thousands of pueruli are taken on collectors for shore ongrowing in a ‘biologically neutral’ exchange for commercial quota (Anon., 1996; Booth et al., 1999). (A similar approach is being considered in Australia; Thomas et ul., 1998.) Despite these initiatives, eventual use of pueruli cultured from eggs rather than taken from the wild is likely to be most acceptable, and will lead to more regular and predictable supplies of stock; however, commercial hatchery production is still many years off. In a few places, larger lobsters (which may be below or above legal size) are captured for either shore or sea-cage ongrowing (‘fattening’) to market size, or for holding over for shorter periods to attain higher market return. Examples are in India (Rahman & Srikrishnadhas, 1992; Radhakrishnan, 1995), Brazil (Assad et al., 1996), Japan (Kanazawa, 1994) and Australia (Anon., 1998).

30.3

Culture of juveniles

Spiny lobsters are generally tolerant and hardy animals. Their major advantage over clawed lobsters is that they are mainly communal and cannibalism is less of a problem. Ongrowing juveniles might, therefore, appear relatively straightforward and indeed growth rates exceeding those in the wild have been achieved. However, culture trials reported since our last review have revealed problems, including high costs associated with puerulus capture, higher than expected incidence of disease, and high food and infrastructure costs. Growth in crustaceans is affected by many factors, including environmental conditions (Hartnoll, 1982). This section gives results from studies of the growth, survival and biological preferences of juvenile spiny lobsters, and deals first with tropical species. References are made to the growout potential of each species. Lobsters are assumed to be marketable once they reach 200 g in weight, although culture to a greater size may be desirable. Size of Panulirus spp. is usually expressed

558 Spiny Lobsters: Fisheries and Culture

as an orbital CL, while for Jaws spp. CL is usually measured from the antenna1 platform, giving a longer lobster than if measured from the orbit.

30.3.1

Panulirus argus

The potential for commercially ongrowing this species, which occurs in the western North Atlantic from Bermuda to Brazil, was discussed by Ingle & Witham (1968), Ting (1973), Lozano-Alvarez et al. (1981) and Lellis (1991). The puerulus stage does not feed (Herrnkind & Butler, 1986). In Florida, pueruli in summer moult about 4 days after settlement, but take more than twice as long in winter (Butler & Herrnkind, 1991); the interval to the moult appears to be unaffected by the substrate. Post-larval 'algal phase' lobsters live solitarily in vegetation, whereas older, 'post-algal' juveniles aggregate in crevice shelters (Childress & Herrnkind, 1996). Young lobsters choose dark-coloured, architecturally complex structures, particularly when these structures are food rich (Herrnkind & Butler, 1986), and avoid silty habitats (Herrnkind et al., 1988). Older lobsters prefer black shelters over those of other colours (Cobb, 1990), and generally occupy dens with only one opening (Kanciruk, 1980). There is, therefore, a general change towards a communal (although not necessarily strongly gregarious) habit with age (Marx & Herrnkind, 1985; Glaholt, 1990), particularly in conditions of low predation risk and high density (Eggleston & Lipcius, 1992). Juveniles from Florida do not tolerate sustained temperatures below 156°C or above 32.2"C, growing most rapidly at 25-27°C (Witham, 1973). For those from Antigua, optimal growth is at 29-30°C (Lellis & Russell, 1990; Lellis, 1991) (Fig. 30.1), males at 29°C reaching 450 g in 12 months and 1.4 kg in 2 years. Young juveniles from Cuba cultured at various temperatures between 26°C and 29°C grew fastest at 29"C, but survival was lower at the higher temperatures; maximum yield was at 28°C (Diaz-Iglesia et al., 1991). and sudden decreases to Pueruli tolerate a gradual lowering of salinity to 19%~ 25%0,but not lower values (Witham et al., 1968). Their survival at salinities other than 35%0is greatly reduced at high (33°C) and low (18°C) temperatures (Field & Butler, 1994). Optimal salinities for larger lobsters are 32-36Y~ (Buesa, 1979). Juveniles in the wild take a diverse, mainly invertebrate diet, but diet changes with age (Mam & Herrnkind, 1985; Cobb, 1990), older lobsters preferring crustaceans and molluscs (Sanchez & Briones Fourzan, 1990; Herrera et al., 1991). Sweat (1968), Witham et al. (1968) and Ting (1973) found that natural marine foods, particularly live invertebrates, were those most readily eaten by captive animals. Amphipods and isopods were among the best foods for very young juveniles; seaweed diets gave less growth than did fish or shellfish (Coton & Nijean, 1987). Lellis (1990), Lellis & Russell (1990) and Pardee (1992) found that live adult Artemia sp. was the best, or only satisfactory, food for first-instar juveniles. However, after the third moult an artificial diet, BioKyowa Fry Feed-C, was

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Fig. 30.1 Growth of spiny lobsters. Top left: Panulirus argus: (a) at 29°C (based on Lellis, 1990, 1991); (b, c) males and females, respectively, in the wild (based on Olsen & Koblic, 1975). Top right: Panulirus homarus: (a) after eyestalk ablation (see text); (b, c) males and females, respectively, in the wild (after Smale, 1978; based on Mohamed & George, 1968); (d, e) males and females, respectively, at ambient temperatures in captivity (after Smale, 1978; based on Berry, 1971). Middle left: Panulirus cygnus (after Chittleborough, 1976): (a) under near-optimal conditions at 25°C; (b, c) at two sites in the wild. Middle right: Panufirus interruptus (after Serfling & Ford, 1975a): (a) at 28°C (extrapolated for sizes above 20 mm CL); (b) at 22°C (extrapolated for sizes above 50 mm CL); (c) in the wild. Bottom left: Panulirus japonicus: (a) at 23-25°C (Kittaka, unpubl. results); (b) in the wild (based on Oshima, 1941); (c, d) males and females, respectively, at ambient temperatures in captivity (Kittaka, unpubl. results). Bottom right: Jams edwardsii from New Zealand: (a, b) males and females, respectively, from a central locality (based on McKoy & Esterman, 1981); (c) males and females from a southern locality (based on Annala & Bycroft, 1985). Juveniles cultured for 3 years at ambient temperatures in northern Japan had similar growth to (a) (Kittaka, unpubl. results).

560 Spiny Lobsters: Fisheries and Culture satisfactory. Young juveniles also survived and grew better on Artemia than on two crustacean reference diets developed for clawed lobsters, the HFX CRD-84 (crab protein) diet and the BML-81s (casein) diet (Lellis, 1992), the latter not being eaten at all. Lellis (1990, 1992) found that diets composed primarily of fish or fish meal, or shrimp feed, resulted in a high frequency of moult death syndrome (MDS; see Conklin et al., 1991). Dry weight food conversion ratio (dry weight food consumed:increase in body weight) was highest at 27°C (1.46:l) and lowest at 33°C (2.63:l). Brito Perez & Diaz-Iglesia (1983) reported a wet weight food conversion ratio (wet weight food consumed:increase in body weight) of 3.97:l for juveniles at 27°C fed molluscs. In a test of a soybean (SB)-based, water-stable feed, Brown et al. (1995) found that weight gains for 200-250-g lobsters were higher and the food conversion ratio was lower in those fed SB plus 20% flax seed, SB plus 2% chemoattractant, SB plus 2% hydrolysed fish, and SB than in lobsters fed SB plus 20% processed fish meal or SB plus 2% hydrolysed poultry. Communally reared juveniles grow slightly more quickly than do isolated individuals, but survival and yield may be similar (Ryther et al., 1988) or even higher (Diaz-Iglesia et al., 1991; Baez Hidalgo et al., 1996) in isolated individuals. Cannibalism can be a problem (Ting, 1973), the availability and type of cover affecting lobster growth rate, survival and frequency of cannibalism (Sweat, 1968). Short light periods (1ight:dark of 8:16 h) can shorten the moult cycle (Quackenbush & Herrnkind, 1983), but this control of moulting may not be possible all year (Lipcius & Herrnkind, 1987). Oxygen uptake by post-larvae is higher at low (31%0)and high (40%0)salinities than nearer 35966, and there is a linear relationship between oxygen uptake and temperature between 19 and 30°C (Brito et al., 1991). Mean oxygen consumption at 27°C for larger (5CL340 g) lobsters at rest is 0.09-0.12 ml (about 0.13-0.17 mg)/g body weight/h) (Maynard, 1960; Buesa, 1979). Oxygen levels are lethal at some value below about 1.95 ml(2.79 mg)/l. The flow rate of near-saturated water (WFR) which provides a resting lobster with sufficient oxygen is related to the weight (W)of the animal by the equation WFR = 19.32W0.61(Buesa, 1979). Eyestalk ablation increases growth rate but it also affects oxygen uptake during the moult, can disturb feeding behaviour and may cause changes in external colour (Maynard & Sallee, 1970; Quackenbush & Herrnkind, 1981; Brito Perez & DiazIglesia, 1987a, b; Diaz-Iglesia et al., 1987), although the metabolic rate of ablated post-larvae is lower than that of controls (Brito et al., 1991). Shore culture of this species from puerulus to marketable size (60 mm CL) in about 1 year appears possible, this taking 1.5-2.5 years in the wild (Fig. 30.1; Briones-Fourzan & Lozano-Alvarez, 1994). Sea-cage ongrowing of larger juveniles has been tried (Assad et al., 1996), but has not always been successful: LozanoAlvarez (1996) found that confinement (with food and shelter) for more than 45 days resulted in reduced growth and increased mortality, probably from increased daytime activity with time, leading to more frequent aggressive encounters and displays of dominance by some individuals over food.

Spiny Lobster Growout 30.3.2

561

Panulirus homarus

Subspecies are widely distributed in the Indian and west Pacific Oceans. They are mainly carnivorous, with mussels and barnacles being major food items (Berry, 1971). Both small and large lobsters select small mussels in preference to larger ones (Smale, 1978). They are gregarious and most often inhabit dens that are tunnelshaped with exits at both ends (Heydorn, 1969). Cultured lobsters have usually been fed shellfish or waste fish. Green mussels (Perna viridis) maintain natural external colour in lobsters better than do clams (Radhakrishnan & Vijayakumaran, 1984). In India, individual lobsters < 15 g consumed up to 2 g mollusc flesh per day; those 51-100 g each consumed up to 11.4 g per day (Rahman et al., 1997). The fastest growth of juveniles in South Africa occurs at 28°C (Smale, 1978), with lobsters reaching 60 mm CL in 18 months. Eyestalk ablation accelerates growth while survival remains high (70%) (Radhakrishnan & Vijayakumaran, 1982, 1984, 1992; Vijayakumaran & Radhakrishnan, 1984). It increases food consumption by 50-96% and can halve the food conversion ratio. Small ablated juveniles show weight gains three to seven times those of animals not ablated, and can gain 350 g within 160 days of ablation. However, bilateral ablation can bring morphological (e.g. growths where the eyes were) and behavioural (e.g. more aggression) changes (Radhakrishnan & Vijayakumaran, 1998). Radhakrishnan & Vijayakumaran (1982, 1984), Silas (1982), and Shanmugham & Kathirvel(l983) contend that it will be routinely possible to culture ablated juveniles to 200 g in 5-6 months, and to double that size in a further 2-4 months. Even without ablation, the interval between settlement and marketable size (about 60 mm CL) for cultured animals is short - possibly as few as 8 months, compared with 1-3 years in the wild (Fig. 30.1; Smale, 1978; Nair et al., 1981; Silas, 1982; Radhakrishnan & Vijayakumaran, 1984; Kuthalingam, 1988). Rahman & Srikrishnadhas (1992, 1994), Srikrishnadhas & Rahman (1993, 1995), Rahman et al. (1994) and Radhakrishnan (1995) advocate shore tank ongrowing, in which 80-100 g juveniles reach 250 g in 5 months and 400 g in 12 months.

30.3.3

Panulirus polyphagus and P. ornatus

Tholasilingam & Rangarajan (1986), Srikrishnadhas & Sundararaj (1989), Rahman & Srikrishnadhas (1992, 1994), Srikrishnadhas & Rahman (1993, 1995), Rahman et al. (1994) and Radhakrishnan (1995) considered the prospects for commercially ongrowing these Indo-West Pacific species. The puerulus of P. polyphagus appears not to feed, and usually moults 2 4 days after settlement (Radhakrishnan & Devarajan, 1986). Juveniles feed well on bivalves, preferring mussels over clams. Small juveniles (<40 mm CL) shelter in small holes, while larger ones use either holes or crevices (Dennis et al., 1997).

562 Spiny Lobsters: Fisheries and Culture Juvenile P . ornatus from Torres Strait grow 31% more rapidly at 30°C than at 26"C, the moult intervals being shorter (Dennis et al., 1997). Juvenile P . polyphagus can be acclimated to salinities at least as low as 17%0and as high as 50% (Kasim, 1986). The lethal low oxygen level for small juveniles is near 0.5 mg/l, and is heavily influenced by the salinity (Kasim, 1986). At 22-28"C, resting oxygen consumption is about O.lCM.17 mg/g body weight/h. Survival of P . polyphugus is 70% higher in those reared in groups, but growth is the same for individuals held in groups and in isolation (Radhakrishnan & Devarajan, 1986). Eyestalk ablation accelerates growth (Srikrishnadhas & Sundararaj, 1989; Juinio-Menez & Ruinata, 1996), but bilaterally ablated P . ornatus are very sensitive to water quality and diet and do not always survive. The average food conversion efficiency of bilaterally ablated P . ornatus (12-17%) is initially higher than that for unilaterally or unablated lobsters, but it does not always remain so. The higher survival and generally higher growth rates of unilaterally ablated lobsters compared with unablated lobsters means that unilaterally ablated lobsters produce the highest overall yield of the three treatments. Radhakrishnan & Vijayakumaran (1992) obtained 530 g and 1.38 kg weight gains over about 200 days for immature and mature P . ornutus, respectively, ablated and fed mussel. However, bilateral ablation brings about morphological and behavioural changes (Radhakrishnan & Vijayakumaran, 1998), at least in P . ornatus. Tholasilingam & Rangarajan (1986) reported that juveniles (presumably P . polyphagus) cultured on a diet of green mussels had a wet weight food conversion ratio of 6: 1. They expected to be able to rear pueruli to marketable size (unspecified) in 12-15 months, compared with 2-3 years to reach 200 g in the wild (Kagwade, 1987). (Panulirus ornutus appear to grow faster in Torres Strait, reaching 75 mm CL - about 400 g - in just over 1 year; Dennis et al., 1997.) Rahman & Srikrishnadhas (1992, 1994), Srikrishnadhas & Rahman (1993) and Radhakrishnan (1995) advocate shore tank ongrowing of P. ornatus, with 80-100-g juveniles reaching 250 g in 5 months and 500 g in 8-12 months.

30.3.4

Panulirus cygnus

Chittleborough (1974a, 1975), Phillips (1985, 1988) and Anon. (1989) considered the potential for ongrowing this subtropical Western Australian species. The puerulus does not feed (Lemmens, 1994), and moults to the juvenile a few days after settlement. Young juveniles occupy small holes (usually with a single entrance) in reefs, particularly where there is also weed cover (Jernakoff, 1990). The optimum temperature for growth and survival of juveniles is 25-26°C (Chittleborough, 1974a, 1975, 1976) (Fig. 30.1). Short exposure to temperatures of up to at least 34°C are tolerated (Chittleborough, 1975), as are salinities between 25%0 and 45%0(Dall, 1974).

Spiny Lobster Growout

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The natural diet of juveniles is a mixture of coralline and fleshy algae, and a range of invertebrates dominated by molluscs (Joll & Phillips, 1984). In captivity, juveniles also accept a wide variety of food, but prefer marine shellfish, and grow most rapidly when fed daily (Chittleborough, 1974a, 1975). At 26"C, a 2-year old consumes 2.67 g of food (as abalone muscle) per day, with a wet weight food conversion ratio of about 3.6: 1 (Chittleborough, 1975). Young juveniles are solitary until about 1.5 years old. Growth rate does not differ between isolated and grouped individuals over the first 3 years (Phillips et al., 1977). However, growth is slower in later juveniles held in isolation (Chittleborough, 1975); survival is not directly affected by crowding provided each animal has sufficient food. A mild deficiency of oxygen (60-67% saturation) results in small moult increments, while 47-55% saturation can cause death at the moult (Chittleborough, 1975). Oxygen consumption is 87% higher at night than during the day through increased activity, and twice as much when feeding than not (Crear & Forteath, 1998). Daylength does not affect growth, except that it is slower in continuous darkness. Juveniles with shelters grow more rapidly than those deprived of them; group shelters are generally preferred over single shelters (Chittleborough, 1974a). Crustecdysone injection promotes moulting in young juveniles, but the response may be highly temperature dependent (Dall & Barclay, 1977). Handling lobsters up to 2 weeks before a moult can reduce the moult increment. Handling newly moulted animals often results in limb loss and other damage, and therefore less growth. Few, and seldom lethal, infections have been found among cultured juveniles (Chittleborough, 1974a, 1975). Lobsters reach marketable size (60 mm CL) 2 years from the puerulus when grown at about 25°C compared with 3-4 years in the wild (Chittleborough, 1974b, 1976; Phillips et al., 1977, 1983) (Fig. 30.1).

30.3.5

Panulirus interruptus

Serfling & Ford (1975a, b), Alba (1980) and Alvarez Torres (1980) considered the potential for ongrowing this subtropical eastern North Pacific species. The puerulus moults 9-10 days after settlement, apparently requiring the presence of surf grass, algae, or rocks with epifauna (Serfling & Ford, 1975b). Fastest growth is at 28°C (Serfling & Ford, 1975a) (Fig. 30.1), although the optimal culture temperature may be nearer 24°C (Blecha, 1972). Natural food includes shellfish, other crustacea, worms, echinoderms and fish (Carlberg, 1975), and some artificial foods are not readily accepted (Serfling & Ford, 1975a). Blecha (1972) reported a wet weight food conversion ratio of about 9:l for juveniles fed molluscs. At 1617"C, lobsters in a surf-grass habitat ingest 4-13 cal(l7-54 J)/g body weight/day, but store less than 50% of the assimilated energy (Winget, 1968). Calorific intake is higher in small captive animals, and increases as temperature increases (Blecha, 1972).

564 Spiny Lobsters: Fisheries and Culture Oxygen consumption in resting 200-600-g lobsters varies from 0.03 (at 13°C) to 0.14 (at 30°C) ml/g body weight/h (about 0.04-0.20 mg/g body weight/h) (Winget, 1969; Blecha, 1972). Equivalent values for active animals are O.OW.15 ml (about 0.09-0.21 mg) oxygen. The oxygen level at which the animal's resting oxygen uptake begins to vary with the external oxygen tension is between 2 and 3 mg/l. Young juveniles prefer Phyllospadix sp. habitats over sand, rock and most other plant habitats (Parker, 1972; Engel, 1979). Older animals seem to prefer long shelters (20 cm) over short ones (10 cm) (Parker, 1972), shelters with more than one entrance, entrances which are much smaller than the inner diameter of the den, shelters with a top cover and a back wall (but not necessarily side walls) (Spanier & Zimmer-Faust, 1988) and large shelters over small ones (Zimmer-Faust & Spanier, 1987). Juveniles and adults in the wild are highly gregarious (Briones-Fourzan & Lozano-Alvarez, 1994). However, in captive animals, large males in particular may become aggressive during foraging, this increasing when shelter is scarce (Roth, 1972). Culture from puerulus to a marketable size (60 mm CL) appears possible in 12 months (Fig. 30.1).

30.3.6

Panulirus japonicus

The puerulus stage of this subtropical western North Pacific species lasts for 12-1 5 days when cultured at 24-26"C, and appears not to feed (Kittaka & Kimura, 1989; Yamakawa et al., 1989). Pueruli and young juveniles appear to be solitary (Yoshimura & Yamakawa, 1988). Older juveniles are more gregarious, and select crevices where the crevice depth is less important than the crevice frontage and height (Chen et al., 1987). Young juveniles are associated with algae (where they feed on small invertebrates) and small holes (Fushimi, 1978; Yoshimura & Yamakawa, 1988; Norman et al., 1994; Yoshimura et al., 1994). These and older juveniles have been cultured on a diet of fish and shellfish (e.g. Kittaka & Kimura, 1989). In animals weighing 50-300 g, fresh fish was consumed at about 1% of body weight per day at 17"C, and 5-15% of body weight at 25"C, depending on size (Inoue, 1964). Fish such as mackerel and sardine as food often resulted in reduced weight gain, poor colour and poor-quality meat (Kanazawa, 1994). Matsuoka et al. (1978, 1979, in Kanazawa, 1994) obtained good growth with commercial pelleted diets developed for red sea bream as well as with the Oregon moist pellet. Moulting is more frequent at high than at low temperatures, and among young juveniles compared with older animals (Oshima, 1941). Female growth rate is less than that of males from the third year on (Fig. 30.1). Juveniles grow more quickly cultured at 23-25°C than in the wild, reaching 48 mm CL in the first year (Kittaka, unpubl. data). The upper temperature limit is about 28°C (references cited in Sugita & Deguchi, 1994). Feeding ceases near 12°C (Inoue, 1964).

Spiny Lobster Growout

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Adults become moribund in 50,60 and 70% oceanic seawater when exposed for 5 , 10 and 20 min, respectively (Nishimura et al., 1972). Oxygen consumption rate is 0.014 ml (about 0.02 mg) and 0.079 ml (about 0.11 mg)/g body weight/h at 12°C and 27"C, respectively for late juveniles, presumably at rest (Morooka, 1966, in Sugita & Deguchi, 1994). For 25-350-g lobsters held at 17"C, oxygen consumption at rest is around 0.05 ml (about 0.07 mg)/g body weight/h, but may reach 0.20 ml (0.29 mg) during activity (Nimura & Inoue, 1969). The lethal low oxygen level is about 1 ml (1.43 mg)/l.

30.3.1

Jasus edwardsii

This temperate water species lives in New Zealand and Australia. Booth (1989), Hollings ( I 99 l), Bunter (1992), Tong & James (1997) and Thomas et al. (1998) have summarized prospects for its commercial ongrowing. Pueruli often occupy small crevices and holes (Booth, 1979; Edmunds, 1995), while later juveniles most often occur in wide, horizontal shelters with a roof and more than one entrance (Gabites, 1990). Any feeding by pueruli is probably confined to small, soft materials (Nishida et al., 1990). Cultured at 18.5"C, the puerulus stage lasts for 19 days from metamorphosis (Kittaka, unpubl. data). For animals from the wild in central parts of New Zealand, the interval between settlement and the first moult ranges from 9 days in summer (when sea temperatures are about 16°C) to 25 days in winter (12°C); the duration of the second juvenile instar varies seasonally between 25 and 70 days (Booth & Stewart, 1993). Pueruli and young juveniles are asocial, but as they grow they become increasingly communal, often aggregating in dens (MacDiarmid et al., 1998). Pueruli from oceanic waters with temperatures around 17°C do not tolerate without acclimatization temperatures above 26°C or salinities below 26%0 (Kittaka, unpubl. data). Early juveniles are only slightly more tolerant, but older animals can be acclimatized to salinities at least as low as 15%0 (Stead, 1973). The optimum temperature for growth and survival of juveniles is 18-20°C (Hollings, 1988; Manuel, 1991; Bunter & Westaway, 1993),males growing at a faster rate than females (Hooker et al., 1997). In Tasmania, lobsters at 18°C grew 15% more rapidly than did those at ambient temperature (mean 16°C) (Thomas et al., 1998). Higher temperatures can bring reduced growth and survival (Hooker et al., 1997). The critical temperature in South Australia for holding larger lobsters is about 22°C (Anon., 1998). In nature, juveniles eat a wide range of mainly sessile or slow-moving species, including other crustacea, molluscs and echinoids (Fielder, 1965a; McKoy & Wilson, 1980; Edmunds, 1995). They often prefer small over large prey individuals. Captive lobsters select foods of marine origin over those terrestrial (Fielder, 1965a). Young juveniles eat and grow well on a wide range of marine foods, especially fresh mussels. Blue mussels (Mytilus sp.) are more acceptable and lead to better growth and colour in small captive lobsters than do green mussels (Perna canaliculus) (James,

566 Spiny Lobsters: Fisheries and Culture 1996; James & Tong, 1997). Fresh, rather than aged (including frozen), mussels produce best growth in juveniles, particularly when the lobsters are fed daily instead of every third day (James & Tong, 1997). Lobsters fed frozen mussels were 20-50% smaller and the intermoult period 10-30% longer than in those fed fresh mussels. Juveniles fed unopened mussels grew the same or slightly more quickly than those fed opened ones (James, 1998), this surprising outcome possibly being due to deterioration of the flesh of the opened shells. In sea-cage trials, animals fed mussels at 5% of their body weight three times a week grew more rapidly than those fed 15% once a week (S. Marwick, Big Glory Seafoods, Stewart Island, pers. comm.). Kittaka (unpubl. data) found wet weight food conversion ratios for small juveniles fed mussels to be between about 5:l (at 12°C) and 7:l (at 20°C). These are very high efficiencies compared with those found for larger juveniles fed mussels, where 3045 mm and 50-65 mm CL lobsters at 1619°Cconsumed daily an average 2.05 g and 2.88 g, respectively, with wet weight conversion ratios over 6 months of 14:l and 22:1, respectively (James & Tong, 1998a). In Tasmania, small juveniles fed mussels, provided with shelter and maintained at 18"C, gave the best growth (1.32% body weight per day), survival (98%) and food conversion ratio (1:l dry weight food:wet weight animal gain) (Thomas et al., 1998). Artificial diets gave slower growth and lower survival, and often pale coloration. Although very small juveniles require mussels to be opened (Tong & James, 1997), the ability of larger lobsters to open and feed on mussels appears to be innate (James & Tong, 1998b). The maximum or critical shell length that J . edwardsii can open is strongly correlated with CL. Lobsters from three size classes (25-70 mm CL) presented with a range of unopened mussel sizes prefer small mussels (6-20 mm shells), whereas most food is consumed from mid-sized (1 1 4 0 mm) mussels; the preferred mussel size is about half the critical size. Young juveniles had low survival when fed casein-based diets (Gerring, 1992). Most deaths occurred at the moult, with features consistent with MDS. Commercial soy lecithin containing about 40% phosphatidylcholine led to a marked reduction in the occurrence of moult death when added to the diets at 10% of the dry weight. There was no effect when it was added at 5% dry weight. Thomas et al. (1998) found that although fresh mussels led to better growth than did prawn pellets or a formulated moist diet, juveniles provided with the prawn diet supplemented once or three times per week with mussels had growth as fast or faster than those fed mussels alone. Small juveniles provided with shelter do not grow differently but survive better than those without shelter (James & Tong, 1998~).But the need for shelter appears to decline the longer the lobsters are confined. Thomas et al. (1998) found that juveniles in tanks with mesh on the floor - which might assist lobsters at the moult grew and survived at the same rate as those in tanks without it. Diet affects the degree of paling in exoskeletal colour of captive juveniles (Thomas et al., 1998). When fed either green mussels or Munida sp., lobsters maintained a deep red external colour (Manuel, 1991; Rayns, 1991). However, James & Tong

Spiny Lobster Growout

567

(1997) found that, although natural red colour was retained with both fresh and aged blue mussels, green mussels gave a light pink exoskeleton, which reversed when the lobsters were again fed blue mussels. Lobsters grown for 70 days on a white background became lighter in colour than those on a black background, but colour was unaffected by photoperiod (Manuel, 1991). However, background colour did not affect intensity of lobster colour in another study, using small juveniles (Stuart et ul., 1996). Crowding reduces growth rate among juveniles (Rayns, 1991). Mortality is also highest under crowded conditions; large individuals survive better than smaller ones in tanks with a mix of sizes, and cannibalism may occur. Young juveniles (about 35 mm CL) were each estimated to require about 20 cm2 of tank area and late juveniles (75 mm CL) about 290 cm2. Lobsters held in tanks downstream of either similar-sized or larger animals had slower growth (Rayns, 1991). Tong (1993) found that for young juveniles, weight increase was 40% less for those at 200 per m2 than for those at 50 per m2, even though survival was high in all treatments. In juveniles, unilateral eyestalk ablation can (but not always; Bunter & Westaway, 1993) increase moult frequency, and bilateral ablation can increase moult increment, both thereby speeding up growth (Rayns, 1991). Both growth and mortality were highest in bilaterally ablated animals. For young juveniles, continuous light produced least growth, while three light cycles in 24 h resulted in most growth (Brett, 1989). In trials with a single light-dark cycle every 24 h, more rapid growth took place when lobsters were cultured under a long, rather than short, light period. Manuel (1991), however, found no difference in growth rate between juveniles reared under a 12:12 1ight:dark cycle compared with those kept in constant darkness. Oxygen consumption for 300-730-g lobsters at rest at 15°C is about 10 pmol/kg body weight/min (about 0.02 mg/g body weight/h), but is three times greater just after vigorous exercise (Waldron, 1991). Oxygen consumption at 17°C is 25% higher than at 15°C. Oxygen uptake of resting animals is maintained down to a critical inspired tension of around 80 Torr. Oxygen consumption is 48% higher at night, when lobsters are active (Crear & Forteath, 1998). The total ammonia excretion rate increases with increased temperature and body weight, is higher at night, and increases up to sixfold with feeding (Crear & Forteath, 1998). Small juveniles can tolerate surprisingly high concentrations (up to at least 360 mg/l) of suspended sediment (Perry, 1997). Lobsters taken in the New Zealand fishery have low rates of debilitating disease and parasite infestation (Booth & Breen, 1992), the most obvious problem being chitin and tissue erosion along the margins of the telson and uropods. Rayns (1991) observed similar, presumably bacterial, shell disease in about 13% of his captive animals, and concluded that diet and exposure to infected animals were important factors in its incidence. However, there can be other, more extensive disease problems in captive lobsters, particularly when associated with poor water quality in recirculating water systems: invasive fungal infection by Huliphthoros milfordensis with secondary vibriosis; gill fouling with filamentous bacteria (Leucothrix sp.),

568 Spiny Lobsters: Fisheries and Culture fungi, nematodes and ectocommensal ciliates; Vibrio infection, including that associated with tissue swelling (turgid lobster syndrome); and a syndrome reminiscent of necrotizing hepatopancreatitis (Diggles, 1999). Supersaturation of water with air has also brought about some large losses of animals in live-holding tanks (Booth, unpubl. data). Wild lobsters off central New Zealand reach a marketable size (75 mm CL) about 3 years after settlement (Fig. 30.1). Hollings (1991) expected to be able to raise small juveniles to 25&350 g within 3 years using shore tanks for the first year, and then low-cost sea-cages over the following 2 years. He estimated the 1991 cost of production to be US $7 per animal compared with a market value of US $8. However, his growth estimates may be overoptimistic (Hooker et al., 1997; Tong & James, 1997).

30.3.8

Other cool-water species

The behaviour and growth of juveniles of other Jaws subgroup lalandii spp. seem to be similar to those of J. edwardsii. Of particular note is that South African J. lalandii avoid waters where the oxygen concentration is less than 2 ml (about 2.9 mg)/l (Newman & Pollock, 1971) and tolerance to low oxygen levels may be lower in the presence of reduced compounds such as sulphdes (Bailey et al., 1985). There is a general decrease in survival, growth and ingestion, and an increase in intermoult period, with decreasing levels of oxygen saturation at 13"C, 80% dying at 35% saturation, the lowest level tested (Beyers et al., 1994). Jasus lalandii is primarily a carnivore with limited ability to digest plant tissue (Barkai et al., 1996). Mussels and small invertebrates are especially important in the diet of this species; lobsters prefer small over large shellfish, and those about 55 mm CL have an optimal daily feeding rate of around 5 kJ/day (Grifiths & Seiderer, 1980; Barkai & Branch, 1988). Interestingly, this lobster also actively selects and can digest sponges (Barkai et al., 1996). Zoutendyk (1988a) estimated the annual consumption of carbon by an animal 97 mm CL under ideal feeding conditions to be 68.3 g, which is equivalent to about 176.4 g of mussel dry mass; mean absorption efficiency is about 80% (Zoutendyk, 1988b). Hazel1 (University of the Western Cape, pers. comm.) found that at nearambient temperatures (mean 14.5"C), small juveniles fed every 1-2 days had moult increments up to 44% larger and intermoult periods 52% shorter than those in nearby wild populations. The puerulus stage of the Australasian Jasus verreauxi lasts for about 25 days when cultured at 18-20"C, and moults without feeding (Kittaka et al., 1997). After 160 days at 15-18°C (and seven moults) it reaches 26 mm orbital CL. Juveniles in the wild possibly reach 55-60 mm CL (about 100 g) 1 year after settlement (Lie, 1969). Juveniles feed well on mussels and probably grow most rapidly at a temperature slightly greater than 20°C (Kittaka, unpubl. data).

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The puerulus stage of the North Atlantic species, Palinurus elephas lasts for 15 days at 17-19°C (Kittaka & Ikegami, 1988). Young juveniles in nature reach 75 mm CL in 3-4 years (Ceccaldi & Latrouite, 1994). An individual grown at 15-20°C reached 44 mm orbital CL in the first year after settlement and 66 mm (260 g) in 2 years (Kittaka, unpubl. data). In nature, echinoids, along with algae and other invertebrates, are the main food items (Mercer, 1973); in captivity, brittlestars and mussels are more readily eaten than fish (Hunter et al., 1996). Oxygen consumption is 0.04 ml (about 0.06 mg)/g body weight/h at 15°C (Wolvekamp & Waterman, 1960).

30.4

Summary of conditions for juvenile growout

Knowledge of the optimal conditions for growout of juvenile spiny lobsters is fragmentary and experimental results are sometimes contradictory, but some generalizations can be drawn. These, along with general issues concerning juvenile ongrowing, are summarized below.

30.4.1

Temperature

Water temperature strongly influences the growth of juvenile spiny lobsters, and relations between it, growth and mortality rate are important in determining the economic viability of lobster ongrowing. Growth rates vary markedly between species, those in warmer waters generally growing at the fastest rate. A wide range of temperatures is tolerated by individual species. Temperatures above ambient (but up to a maximum) usually result in faster growth, greater (but not always, e.g. Hooker et al., 1997) than that seen in the wild. The faster growth stems mainly from more frequent moulting rather than greater moult increment. Optimal growth in juveniles occurs at about 18-20°C (for J. edwardsii from Australasia) to 29-30°C ( P . argus from Antigua). However, the temperatures may not be applicable over the geographical range of individual species, and they may vary with age. The lower food conversion efficiency, higher food consumption, greater activity, and problems such as increased incidence of disease or opportunity for water quality failure, may partially negate gains from faster growth at higher temperatures.

30.4.2

Salinity

Palinurids are mainly restricted to oceanic and near-oceanic waters, and are generally poikilosmotic over their tolerated salinity ranges. Juveniles tolerate, at least

570 Spiny Lobsters: Fisheries and Culture over several days and according to species, gradual reductions in salinity to surprisingly low values, at least 20Ym below oceanic salinity. Salinity of the seawater affects the flavour of spiny lobster flesh (Chapter 29).

30.4.3

Food

Food may comprise 50-70% of the unit cost of production of spiny lobsters (Crossland, 1988; Radhakrishnan, 1995; Jeffs & Hooker, in press). It must have high nutritional value and be acceptable to the lobsters, available all year round at reasonable cost, and be easy to store and handle. The culturist needs to determine the feeding level that optimizes growth rate and conversion efficiency. Measures of nutritional condition are being developed for lobsters, which can be used in studies of food suitability. These include lipid, protein, glucose and glycogen content, length/weight ratio and a moult stage/increment index (Robertson et al., 1996; Jeffs et al., 1999). Slow-moving or sessile benthic marine invertebrates, the main food of most spiny lobsters in the wild, have been useful in culture trials. Marine foods are preferred over terrestrial, and shellfish (particularly mussels) over finfish. Jams edwardsii grow more rapidly on fresh mussels than on aged ones and juveniles grow just as well, if not better, on unopened mussels, despite the energy cost associated with opening the mussels, in turn bringing less tank maintenance. The effectiveness of a bait in a commercial fishery is not necessarily an indication of its suitability as food (Chittleborough, 1974a). The amount of food eaten varies according to moult state and size (age) of animals, and increases with water temperature. Daily feeding rates for mid- and late juveniles of around 0.05 kJ/g body weight, 1-1 5% of body weight and 3-1 1 g/lobster have been suggested. The puerulus stage of most species appears not to feed. Daily feeding of juveniles to excess (with removal of uneaten food) gives fastest growth. Food might be offered late in the day, when lobsters most often feed, so as to minimize the time for food decay. Wet weight food conversion ratios between 3.6:l and 9:l have been reported, sometimes with more efficient conversion after eyestalk ablation, but much less satisfactory conversion efficiencies (up to 22: 1) have also been noted. Other factors affecting conversion efficiency include the type of food, lobster age and body size, feeding level, salinity and temperature (Bartley et al., 1980). High levels of polyunsaturated fatty acids of the n-3 series are required for good growth and survival in many crustacea (Castell, 1983). Carotenoid pigments such as astaxanthin may be required to maintain good exoskeletal colour. Artificial diets can meet such needs, and may be more dependable and convenient than natural foods because of fewer problems with collection, seasonal variation in quality and storage and handling. A suitable artificial feed has not yet been developed, although some prawn and fish diets appear promising. Spiny lobsters require a hard pellet which they can hold in their legs and from which they can ‘spin off’ pieces (Ryther et al.,

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1988). Furthermore, standard diets devised for clawed lobsters (e.g. Conklin, 1980; Castell et al., 1989), and against which the usefulness of new diets can be compared, have not all been useful for spiny lobsters. Specific requirements for one species may not apply to others, even when two species are closely related (Conklin, 1980). Chemical attractants may be necessary for lobsters to eat otherwise unpalatable diets, and wild-caught animals may need a weaning period before they will accept and thrive on artificial foods (Lellis, 1992). Death at the moult has been widely reported among captive spiny lobsters, often with symptoms consistent with MDS of homarids (Bowser & Rosemark, 1981; Conklin et al., 1991; Lellis, 1992). Causes of MDS may include stress, shortage of oxygen and poor nutrition, including insufficient dietary B vitamin and manganese (Castell et al., 1991). Phosphatidylcholine added as soy lecithin to diets based on casein can result in dramatic reduction in MDS in lobsters (Conklin et al., 1980; Bowser & Rosemark, 1981; Conklin, 1990). A similar result is now emerging for spiny lobsters. However, the need for lecithin depends on the protein source (Kean et al., 1985; Conklin et al., 1991).

30.4.4

Water quality

Ammonia makes up 6&100% of the total excreted nitrogen in crustacea. Excretion rates increase with feeding and with increased temperature and body weight, but can also be influenced by nutritional level, diurnal rhythms, salinity, moult stage and ambient oxygen concentration (Crear & Forteath, 1998). Ammonia can be toxic to crustaceans if allowed to concentrate too much, and even at low levels can inhibit growth. Ammonia tolerance increases with ontogenetic development, and decreases at higher temperatures and at high levels of stress (Forteath, 1990; Young-Lai et al., 1991). In recirculating systems for J. edwardsii, levels of total ammonia should be below 0.5 mg/l and levels of NH3-N should not exceed 0.1 mg/l; nitrite levels should be at or below 1 mg N02-N/1; nitrates should be below 100 mg N03-N/l (but preferably lower to discourage the growth of epibionts); and pH should be 7.8-8.2 (Forteath, 1990; Harvie, 1993). Serfling & Ford (1975a) advise that all plastics should be used with caution until proven safe as some may cause lobster mortality and reduced growth, especially in recirculating systems and at high temperatures. Some metals are toxic, as are contaminants such as detergents. Acceptable levels of various contaminants are given by Van Olst et al. (1980) and Forteath (1990). Separate plumbing to each tank is desirable to avoid downstream hormonal effects and transmission of disease.

572 Spiny Lobsters: Fisheries and Culture 30.4.5

Oxygen

Spiny lobsters have been referred to as oxygen regulators (Winget, 1969), but they are oxygen independent only down to some critical oxygen tension, around 30% saturation (Crear & Forteath, 1998). Oxygen consumption, and the lethal oxygen level, depend on sex, body weight, moult state, water temperature, salinity, time of day and whether or not the lobster is feeding. There is less oxygen present in water the higher the temperature and salinity. For example, at 21"C, resting J. edwardsii require 137% more oxygen than at 13"C, yet there is 16% lower capacity of water for oxygen at the higher temperature (Crear & Forteath, 1998). Soft foods, which break up rapidly, and uneaten food, also increase biological oxygen demand. The much higher oxygen consumption rate at night than during the day needs to be borne in mind. At rest, oxygen consumptions of juveniles held in waters with near natural temperatures and salinities vary according to species from about 0.02 to 0.17 mg/g body weight/h. The low lethal oxygen level appears to be between 0.5 and 3.0 mg/l, depending on species. Minimum dissolved oxygen levels recommended in the literature are between 40% and 80% saturation (Crear & Forteath, 1998). On a per weight basis, larger lobsters consume less oxygen than smaller ones, so they can be held at higher densities. For example, a tank that could maintain 1 t of 450-g P. cygnus would be able to maintain 1.3 t of 2-kg lobsters (Crear & Forteath, 1998). Short periods (days) of starvation had no effect on P. argus oxygen consumption (Conceicao et af., 1996). Supersaturation of water by air (mainly nitrogen) can cause gas bubble disease in crustacea (e.g. Brisson, 1985) and death of spiny lobsters. Nitrogen levels of 105% saturation or more can be dangerous (Forteath, 1990). Saturation levels depend on a number of factors including water temperature, the depth from which the water is drawn and the opportunities for air entrainment (Wolke et al., 1975).

30.4.6

Stocking density

The generally communal nature of spiny lobsters makes them especially suitable for culture, but at excessively high densities growth and survival can be adversely affected. Not all results are consistent, but lobsters held in isolation sometimes show slower growth or lower survival than when in groups, and optimal stocking density may change during life. Density in a nursery for young juveniles might be around 200 animals/m2 (Lee & Wickins, 1992) (but this was too high for J . edwardsii). For a single layer of older juveniles, 351 m2 of tank area may be required to produce 1 t of market-sized animals; an overall annual yield could be 1 1.4 t/ha. However, these density estimates for larger animals appear pessimistic against those of Rayns (1991) given earlier for J . edwardsii, and Phillips' (1985) estimate of up to 25 kg/m2 for P. cygnus.

Spiny Lobster Growout 30.4.7

573

Disease

Although in the wild spiny lobsters are generally hardy and robust, and appear relatively free from disease, in captivity infection at any stage of culture can occur (see Stewart, 1980; Provenzano, 1985; Chapter 3 l), particularly when poor quality water is recirculated. Problems include build-up of external growths, infection of damaged limbs, fungal disease, and development of bacterial shell disease, infection by Vibrio spp., and bacterial, nematode and ciliate infestation of the gills (e.g. Fan et al., 1993; Abraham et al., 1996; Diggles, 1999). Diet, water quality and degree of crowding can affect the onset and severity of disease. Gaffkemia, an often lethal bacterial infection of the haemolymph in clawed lobsters (Stewart, 1980), appears to be widespread and can affect spiny lobsters (Steenbergen & Schapiro, 1974).

30.4.8

Endocrine factors

Eyestalk ablation can spectacularly promote growth in spiny lobsters, mainly through accelerating moult frequency; however, survival has often been low and there have been adverse behavioural, morphological, and external colour changes. Ablated lobsters may be more susceptible to poor water quality, reduced oxygen levels and diet than whole animals (Radhakrishnan & Vijayakumaran, 1984). Unilateral ablation, although not promoting growth so strongly, may give better survival and yield than bilateral ablation or no ablation. Crustecdysone treatment can also promote moulting. Males grow more quickly than females, both before and after maturity is reached.

30.4.9

Other conditions

The type of habitat provided needs to accommodate the complex social behaviour of spiny lobsters (e.g. Atema & Cobb, 1980; Kanciruk, 1980). Young juveniles are generally solitary while older animals are communal. All may grow more slowly when deprived of shelter, but this is not necessarily so. Captive animals held at high density with no predation risk may choose different styles of shelter than those in the wild, and preference may change with age. Animals held in smooth PVC tanks often have difficulty moulting, so tank floors may be roughened to give grip (Phillips et al., 1977). Provision of vertical mesh can lead to better use of tank space (Rayns, 1991). There is potential for the development of a hide design which is easy to clean, probably modular, yet acceptable to the lobsters. The light cycle may be varied to modify behaviour and promote feeding and growth. The minimum daytime brightness recognized by P. juponicus is about

574 Spiny Lobsters: Fisheries and Culture 2.3 x lx (Koike et al., 1996). Tanks usually contain similar-sized animals because large individuals may dominate for shelter and food (e.g. Fielder, 1965b; Rayns, 1991) and bring about reduced growth and more cannibalism. Although much less of a problem than in clawed lobsters, cannibalism is common among spiny lobsters, especially where there is shortage of food or shelter. Moulting or just moulted animals seem to be most vulnerable (e.g. Beyers et al., 1994), but it is not certain whether healthy animals are attacked. Optimizing the many factors outlined above will help to reduce stress, which can bring irreversible physiological change and death (Taylor et ul., 1997). Stressed animals also require more oxygen and are more susceptible to disease. Intrusions such as bright lights, unnecessary movement and handling (particularly near the moult) are all stressful. Indicators of stress used for crustaceans include haemolymph lactate, glucose, protein, hormone, ion and pH levels, and rate of oxygen uptake (Paterson & Spanoghe, 1997; Taylor et al., 1997).

30.5

Other aspects

In most countries the holding of lobsters smaller than minimum legal size is illegal, so legislative changes will be required to allow commercial growout. Large-scale growout involves not only biological considerations but also technical factors, e.g. the design of facilities and the efficient use of space and water. These have been reported for clawed lobsters, but not all these systems will be useful for spiny lobsters. Srikrishnadhas & Rahman (1993), Rahman & Srikrishnadhas (1994) and Radhakrishnan (1995) discussed lobster culture tank system designs for Punulirus spp. Disease can be a problem, particularly in recirculated water systems and because of this, and the high costs associated with shore culture, sea-cages may be a useful alternative in some situations. Sea-cage and shore ongrowing of larger juveniles appear indeed to be economically feasible, at least for some species (Srikrishnadhas & Rahman, 1995; Rahman & Srikrishnadhas, 1994; Rahman et al., 1994; Radhakrishnan, 1995). Enclosures are much less expensive than constructing ponds or tanks, do not need special infrastructure or costly maintenance (Lozano-Alvarez, 1996) and can be easily moved. However, for J. edwardsii in shore tanks, Bunter & Westaway (1993) and Jeffs & Hooker (2000) concluded that to be profitable, there had to be greatly reduced infrastructure and operating costs as well as lowered feed and labour costs, and lower mortality.

Spiny Lobster Growout 30.6

575

Conclusions

Over the past 20 years there has been a great increase in biological information concerning growout conditions for juvenile spiny lobsters. Optimal culture conditions with regard to several factors are now broadly known for several species. However, other factors affecting growth and survival, and the interaction between factors, require further study so that culture conditions can be better improved. Sourcing spiny lobsters for ongrowing is still a problem. Cultured pueruli are not yet available commercially, and even the capture and ongrowing of wild-caught pueruli and small juveniles is still conducted on only a small commercial scale. Probably the largest puerulus capture enterprise is in New Zealand, where thousands are collected for commercial ongrowing on shore in exchange for quota retired from the commercial fishery. The ongrowing ('fattening') of larger juveniles that has taken place in India, for example, for many years is now being investigated in other parts of the world, and appears to be economic for some species. Tropical spiny lobster species in particular grow very quickly. It appears that several species can be cultured from puerulus to a marketable size of 200 g in 2 years (some in 1 year), and 300 g in less than 3 years, but the authors are more cautious about the prognosis for economic success for juvenile ongrowing than they were in 1994. Growth rates seen in the wild have not always been achieved in tanks. Sourcing appropriate feeds, control of disease, and high infrastructure and labour costs also appear to be problematic, more so than had been previously thought. Food conversion ratios have often been poor. Disease outbreaks and high mortalities have occurred, particularly in recirculating systems with water quality problems. There is still no suitable artificial feed. The most optimistic predictions for economic success tend to come from low labour cost economies using fast-growing tropical species. Successful commercial production of slower growing species may eventually come from shore culture in the first few months, followed by less expensive sea-cage ongrowing of the lobsters to market size. Although ongrowing juveniles economically will be much easier than culturing phyllosomas economically, successful commercial lobster production is still a few years off - but inevitable.

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Rahman, M.K. & Srikrishnadhas, B. (1994) The potential for spiny lobster culture in India. Infofish Int., 1, 51-3. Rahman, M.D.K., Joseph, M.T.L. & Srikrishnadhas, B. (1997) Growth performance of spiny lobster Panulirus homarus (Linnaeus) under mass rearing. J. Aquacult. Trop., 12, 243-53. Rahman, M.D.K., Srikrishnadhas, B. & Anandasekaran, A.S.M. (1994) Spiny lobster culture in controlled conditions. J. Aquacult. Trop., 9, 235-9. Rayns, N.D. (1991) The growth and survival of juvenile rock lobster Jasus edwardsii held in captivity. Ph.D. thesis, University of Otago, Dunedin, New Zealand. Richards, P.R. & Wickins, J.F. (1979) Lobster culture research. Lab. Leafl., No. 47. UK Ministry of Agriculture, Fisheries and Food. Robertson, D., Butler, M.J. & Dobbs, F.C. (1996) Evaluation of potential indices of nutritional condition of the Caribbean spiny lobster. Twentyfourth Annual Benthic Ecology Meeting, Columbia, South Carolina, March 7-10, 1996, p. 71. Roth, A.C. (1972) Agonistic behavior and its relationship to group density, size differences, and sex in the California spiny lobster, Panulirus interruptus (Randall). M.Sc. thesis, San Diego State College, San Diego, USA. Ryther, J.H., Lellis, W.A., Bannerot, S.P. & Chaiton, J.A. (1988) Crab and spiny lobster mariculture. Part I1 Spiny lobster mariculture. Report 538-O140.03(l)), US. Aid Grant. Sanchez, C. & Briones-Fourzan, P. (1990) Alimentacion de las langostas Panulirus guttatus y P . argus (Latreille 1804) en el Caribe Mexicano. An. Inst. Cienc. Mar. Limnol. Univ. Nac. Auton. Mexico, 17, 89-106. Serfling, S.A. & Ford, R.F. (l975a) Laboratory culture of juvenile stages of the California spiny lobster Panulirus interruptus (Randall) at elevated temperatures. Aquaculture, 6, 377-87. Serfling, S.A. & Ford, R.F. (1975b) Ecological studies of the puerulus larval stage of the California spiny lobster, Panulirus interruptus. Fish. Bull., 73, 36g77. Shanmughan, S. & Kathirvel, M. (1983) Lobster resources and culture potential. In Mariculture Potential of Andaman and Nicobar Islands - an Indicative Survey (Ed. by K. Alagars-Wami), pp. 61-5, CMFRI Bull. NO. 34. Silas, E.G. (1982) Major breakthrough in spiny lobster culture. Tech. Ext. Ser., No. 43. Marine Fisheries Information Service, Central Marine Fisheries Research Institute, Cochin, India. Smale, M.J. (1978) Migration, growth and feeding in the Natal rock lobster Panulirus homarus (Linnaeus). Invest. Rep., No. 47, The Oceanographic Research Institute, Durban, South Africa. Spanier, E. & Zimmer-Faust, R.K. (1988) Some physical properties of shelter that influence den preference in spiny lobsters. J. Exp. Mar. Biol. Ecol., 121, 13749. Srikrishnadhas, B. & Rahman, M.D.K. (1993) A growout system for spiny lobsters. Seafood Export J., 25, 11-14. Srikrishnadhas, B. & Rahman, M.K. (1995) Growing spiny lobsters - a profitable venture. Seafood Export J., 26, 13-17. Srikrishnadhas, B. & Sundararaj, V. (1989) Status and scope for lobster culture. Seafood Export J., 21, 19-24. Stead, D.H. (1973) Rock lobster salinity tolerance. Fish. Tech. Rep., No. 122. NZ Ministry of Agriculture and Fisheries. Steenbergen, J.F. & Schapiro, H.C. (1974) GaMtemia in California spiny lobsters. Proc. 5th Ann. Wkshop World Maricult. Soc., 13943. Stewart, J.E. (1980) Diseases. In The Biology and Management oflobsters, Vol. 1 (Ed. by J.S. Cobb & B.F. Phillips), pp. 30142. Academic Press, New York, USA. Stuart, T., Macmillan, D.L. & Thomas, M. (1996) The effect of background colour on the colour of developing juvenile rock lobsters, Jasus edwardsii. (Crustacea: Decapoda). Mar. Freshwat. Behav. Physiol., 27, 269-73.

584 Spiny Lobsters: Fisheries and Culture Sugita, H. & Deguchi, Y. (1994) Shipping. In Spiny Lobster Management (Ed. by B.F. Phillips, J.S. Cobb & J. Kittaka), pp. 503-9. Fishing News Books, Blackwell Scientific Publications, Oxford, UK. Sweat, D.E. (1968) Growth and tagging studies on Panulirus argus (Latreille) in the Florida Keys. Tech. Ser., No. 57. State of Florida Board of Conservation, USA. Tacon, A.G.J. (1998) Global trends in aquaculture and aquafeed production 1984-95. In International Aquafeed Directory & Buyers’ Guide 1997198, pp. 5-37. Turret RAI, Uxbridge, UK. Taylor, H.H., Paterson, B.D., Wong, R.J. & Wells, R.M.G. (1997) Physiology and live transport of lobsters: report from a workshop. Mar. Freshwat. Res., 48, 817-22. Tholasilingam, T. & Rangarajan, K. (1986) Prospects on spiny lobster Panulirus spp. culture in the east coast of India. Proc. Symp. Coastal Aquacult., 4, 1171-5. Thomas, C., Crear, B., Ritar, A,, Mills, D. & Hart, P. (1998) Research into the aquaculture of the southern rock lobster (Jasus edwardsii) in Tasmania. Fish. Today, 11(6), 22-7. Ting, R.Y. (1973) Culture potential of spiny lobster. Proc. Fourth Ann. Workshop World Maricult. Soc., Monterrey. Jan 23-26. 1973. Louisiana State University Division of Continuing Education, USA. Tong, L. (1993) Progress toward spiny lobster farming in New Zealand. Lobster Newslett., 6(2), 14. Tong, L. & James, P. (1997) Rock lobster farming. Aquacult. Update, Autumn, 5 4 . Van Olst, J.C., Carlberg, J.M. & Hughes, J.T. (1980) Aquaculture. In The Biology and Management of Lobsters, Vol. 2 (Ed. by J.S. Cobb & B.F. Phillips), pp. 333-84. Academic Press, New York, USA. Vijayakumaran, M. & Radhakrishnan, E.V. (1984) Effect of eyestalk ablation in the spiny lobster Panulirus homarus (Linnaeus): 2. On food intake and conversion. Ind. J. Fish., 31, 148-55. Waldron, F.M. (1991) Respiratory and acid-base physiology of the New Zealand rock lobster, Jasus edwardsii (Hutton). Ph.D. thesis, University of Canterbury, Christchurch, New Zealand. Winget, R.R. (1968) Trophic relationships and metabolic budget of the California spiny lobster, Panulirus interruptus (Randall). M.Sc. thesis, San Diego State College, San Diego, USA. Winget, R.R. (1969) Oxygen consumption and respiratory energetics in the spiny lobster, Panulirus interruptus (Randall). Biol. Bull., 136, 301-12. Witham, R. (1973) Preliminary thermal studies on young Panulirus urgus. Flor. Sci., 36, 154-8. Witham, R., Ingle, R.M. & Joyce, E.A. (1968) Physiological and ecological studies of Panulirus argus from the St. Lucie Estuary. Tech. Ser., No. 53. State of Florida Board of Conservation. Wolke, R.E., Bouck, G.R. & Stroud, R.K. (1975) Gas-bubble disease: a review in relation to modern energy production. In Fisheries and Energy Production: A Symposium (Ed. by S.B. Saila), pp. 239-65. Lexington Books, Lexington MA, USA. Wolvekamp, H.P. & Waterman, T.H. (1960) Respiration. In The Physiology ofcrustacea, Vol. 1 (Ed. by T.H.Waterman). Academic Press, New York, USA. Yamakawa, T., Nishimura, M., Matsuda, H., Tsujigado, A. & Kamiya, N. (1989) Complete larval rearing of the Japanese spiny lobster Panulirus japonicus. Nippon Suisan Gukkaishi, 55, 145. Yoshimura, T. & Yamakawa, H. (1988) Microhabitat and behavior of settled pueruli and juveniles of the Japanese spiny lobster Panulirus japonicus at Kominato, Japan. J. Crust. Biol., 8, 524-31. Yoshimura, T., Yamakawa, H. & Norman, C.P. (1994) Comparison of hole and seaweed habitats of post-settled pueruli and early benthic juvenile lobsters, Panulirus japonicus (Von Siebold, 1824). Crustaceana, 66, 35745. Young-Lai, W.W., Charmantier-Daures, M. & Charmantier, G. (1991) Effect of ammonia on survival and osmoregulation in different life stages of the lobster Homurus americanus. Mar. Biol., 110, 293-300. Zimmer-Faust, R.K. & Spanier, E. (1987) Gregariousness and sociality in spiny lobsters: implications for den habitation. J . Exp. Mar. Biol. Ecol., 105, 57-71.

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Zoutendyk, P. (1988a) Consumption rates of captive cape rock lobster Jams lalandii. S. Afr. J. Mar. Sci., 6 , 267-71. Zoutendyk, P. (1988b) Feeding, defaecation and absorption efficiency in the cape rock lobster Jams lalandii. S. Afr. J . Mar. Sci., 6, 59-65.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 31

Diseases of Spiny Lobsters L.H. EVANS Aquatic Science Research Unit, Muresk Institute of Agriculture. Curtin University of Technology, P.O. Box U1987, Perth, Western Australia 6845. Australia

J.B. JONES Fish Health Section, Fkheries Western Australia, P.O. Box 20, North Beach, Western Australia 6020, Australia

J.A. BROCK Aquaculture Development Program, Department of Agriculture, Room 400, 1177 AIakea Street, Honolulu, Hawaii 96813, USA

31.1

Introduction

The principal diseases of lobsters comprise bacterial diseases (gaffkemia, shell disease, vibriosis) fungal infections (systemic and superficial mycoses) and parasitic infections. The nature, occurrence and pathogenesis of these conditions have been extensively studied in clawed lobsters and have been the subject of numerous reviews (Stewart, 1975,1980, 1984; Sindermann, 1977,1990; Fisher et al., 1978; Rosemark & Conklin, 1983; Bower et al., 1994). In contrast, reports of disease conditions in spiny lobsters are relatively few (Sindermann, 1990, Bower et al., 1994), although there has been a number of studies relating to host defense responses. The growth of aquaculture over the past decades has provided a stimulus for research into crustacean diseases. The high stocking densities employed in aquaculture and the associated stress on cultured stock facilitates the outbreak and spread of infectious disease. Non-infectious disease states, particularly those caused by inadequate nutrition, also occur. The need to prevent and control disease in cultured species has led to a major research effort into disease diagnosis and treatment and into the nature of internal defence mechanisms.

31.2

Spiny lobster defence mechanisms

The chitinous exoskeleton of spiny lobsters, as in other arthropods (Sugumaran, 1996), is an effective barrier that impedes the entry of infectious agents as well as protecting underlying soft tissue from mechanical damage. In addition to the physical barrier presented by the exoskeleton, antimicrobial secretions and a resident bacterial flora probably function as host defence mechanisms. Invertebrates do not exhibit acquired immunity (Roch, 1999), although proteins with domains belonging to the immunoglobulin superfamily have been demonstrated (Lanz Mendoza & Faye, 1996). 586

Diseases of Spiny Lobsters

587

Rapid sealing of wounds to the exoskeleton prevents loss of haemolymph and minimizes contamination of lobster tissues by foreign agents. The reactions leading to wound repair in spiny lobsters comprise coagulation and haemocyte aggregation followed by melanization of the wound area. These processes are primarily mediated by haemocytes or haemocyte secretory products but also involve haemolymph components (reviews: Sindermann, 1990; Smith, 1991; Bachere et al., 1995; Soderhall et al., 1996; Roch, 1999). Coagulation in spiny lobsters results from the direct conversion of a soluble fibrinogen (coagulogen) into cross-linked fibrin through the action of a coagulin released by the haemocytes (Fuller & Doolittle, 1971a, b; Durliat & Vranckx, 1981; Ghidalia et al., 1981; Hose et al., 1990; Aono & Mori, 1996). Shortly after the commencement of haemocyte aggregation and coagulation, melanin is deposited at the wound site. Melanin is produced by the action of the enzyme polyphenoloxidase on melanin precursors (Unestam & Nylund 1972; Bauchau, 1981) and is said to have antimicrobial properties (Nyhlen & Unestam 1980; Soderhall & Ajaxon, 1982). Foreign agent recognition, inactivation and elimination is effected through host defence responses involving circulating haemocytes, fixed phagocytes, agglutinins or lectins and antimicrobial factors present in the haemolymph (reviews: Bauchau, 1981; Ratcliffe et al., 1985; Sindermann, 1990; Smith, 1991; Soderhall et al., 1996). Immunorecognition is thought to be mediated through the prophenoloxidase system, a cascade of serine proteases and prophenoloxidase present in the haemocytes which is activated by the presence of non-self molecules (Soderhall & Smith, 1986; Soderhall et al., 1996). Subsequent host defence responses comprise cellular mechanisms (phagocytosis, haemocytosis and encapsulation) together with humoral responses involving the actions of circulating antibacterial factors, lectins and other immunologically active molecules. Some of these processes or molecular components have been studied in spiny lobsters. Phagocytosis and encapsulation reactions by haemocyte preparations obtained from Panulirus interruptus have been studied by Hose et al. (1990) and shown to be mainly performed by the granular haemocytes. Circulating agglutinins or lectins have been studied in P . interruptus by Tyler & Metz (1945) and Tyler & Scheer (1945), in P , argus by Acton et al. (1973), in P.japonicus by Ueda et al. (1991), in Jasus verreauxi by Imai et al. (1994) and in J . edwardsii by Ueda et al. (1991) and Imai et al. (1994). Weinheimer’s group have performed extensive studies on bactericidins in P . argus and P . interruptus (Evans et al., 1968, 1969a, b; Weinheimer et al., 1969a, b) and shown them to be inducible and to have a broad specificity which covers a range of antigenic determinants. Panulirus argus was shown by the same group to possess a natural haemolysin for sheep erythrocytes (Weinheimer et al., 1969~).Bactericidal activity has also been demonstrated in P . japonicus (Ueda et al., 1990, 1994) and in the Norway lobster, Nephrops norvegicus (Chisholm & Smith, 1995). The relative importance of cellular and humoral host defence mechanisms in lobsters has yet to be determined. It would seem, however, that circulating

588 Spiny Lobsters: Fisheries and Culture haemocytes play a central role through their involvement both in immunorecognition and in the processes of inactivation and elimination. Rapid advances are being made in the understanding of the mechanisms of host defence in decapod crustaceans. However, the influence of environmental stress or nutritional status of the host on defence responses, both areas of critical importance to animal husbandry and production in aquaculture, have only recently been addressed (Jussila et al., 1998; Hall & van Dam, 1998).

31.3

Diseases caused by biotic agents

Aquaculture of spiny lobsters is in an early stage of development and few studies have been published on diseases in cultured stock. However, disease conditions have been reported in spiny lobsters caught in commercial fisheries or reared in aquaria (Table 3 1.1) In addition, infectious diseases of clawed lobsters, both cultured and wild stock, are well described and may reflect those conditions likely to occur in spiny lobster aquaculture. There is also a growing awareness of the way in which bacterial and fungal diseases of crustaceans, including gaffkemia [a bacterial disease of marine lobsters (Homarus americanus and H . gammarus) caused by Aerococcus viridans var. homari], can be and have been transmitted via commercial movements of stocks (Alderman, 1996).

31.3.1

Viral diseases

Viral disease, a major cause of stock mortality in cultured shrimp (Lightner, 1988) has not yet been described in a lobster species. There have been two reports of viruslike particles in tissues of moribund lobsters (Moore & Li, 1985; Chong & Chao, 1986) but in neither study were the particles identified as virus.

31.3.2

Bacterial diseases

The major bacterial diseases found in lobsters are gaffkaemia, shell disease and vibriosis. In addition, filamentous and non-filamentous bacteria growing on the external surfaces can contribute to stock mortality under certain conditions (Fisher et al., 1978; Fisher, 1988a). Gafflaemia

Gaffkaemia is a systematic disease caused by the Gram-positive bacterium Aerococcus viridans var. homari (review: Brock & Lightner 1990). Clawed lobsters

Helminths

Protistans

Fungi and oomycetes

Trematode infection (ovaries; juvenile and adult lobsters) Nematode infestation (pueruli and early juveniles) Nemertean infestation (eggs)

Larval infection Microsporidiosis

Gill infection

Shell disease

Not identified

Carcinonemertes sp. Carcinonemertes wickhami

Panulirus cygnus

P. interruptus

Thulukiotrema genitale (Microphallidae)

Vibrio parahaemolyticus and other Vibrio spp. Vibrio harveyi Vibrio spp. Vibrio alginoiyticus Vibrio harveyi-like Unidentified fungal sp. Fusarium solani Didymaria palinuri Fusarium (Rumuluria) branchialis Atkinsiella panulirata Not identified Ameson sp. Ameson sp.

Jasus edwardsii

Panulirus japonicus P. argus P. cygnus P. cygnus P. ornatus P. cygnus

P. elephas P. cygnus P. elephas Homarus garnmarus

Panulirus sp. P. cygnus P. homarus

Not stated

Vibriosis

Shields & Kuris (1990)

Campbell et al. (1989)

Brett (unpubl. obs., cited in Booth, 1988)

Deblock ef al. (1990)

Kitancharoen & Hatai (1995) Bach & Beardsley (1976) Evans (1987) Dennis & Munday (1994)

Alderman (1973) McAleer (1983) Sordi (1958)

Chong & Chao (1986) Evans (1987) Abraham ei al. (1996)

Brinkley et al. (1976)

Iversen & Beardsley (1976) Alderman (1972) Hameed (1994)

P. guttatus Palinurus elephas P. homarus

Shell disease Not identified Not identified Vibrio alginol-vticus

Bobes et al. (1988) Schapiro ei al. (1 974); Steenbergen & Schapiro (1974a)

Aerococcus viridans Aerococcus viridans

Panulirus argus P. interrupius

Gaffkaemia

Bacteria

References

Causative organisms

Lobster species

Condition

Disease agents

Table 31.1 Biotic diseases of spiny lobsters

rD

00

ul

zg

6

k

9

8

E c

P P’

590 Spiny Lobsters: Fisheries and Culture held in inpoundments are commonly affected. The disease is most frequently observed in Homarus americanus, but also occurs in H . gammarus (Stewart, 1980; Gjerde, 1984; Wiik et al., 1987) and P . argus (Bobes et al., 1988). In addition, gaffkemia has been experimentally induced in the Californian spiny lobster, P . interruptus (Schapiro et al., 1974; Steenbergen & Schapiro, 1974a) and in the shrimp Pandalus platyceros (Bower et al., 1994). The aetiology and pathogenesis of gaffkaemia have been elucidated through an extensive series of studies conducted by Stewart and co-workers (reviews: Stewart, 1980, 1984; Sindermann, 1990). The bacteria are free living and gain entry to host internal tissues through wounds or breaks in the exoskeleton. Following entry they concentrate and develop in the hepatopancreas and cardiac tissues before multiplying in the haemolymph. Septicaemia ensues and the number of circulating haemocytes falls dramatically. The bacteria grow by using the free glucose and nonprotein nitrogen of the lobster and eventually cause its death. Host defence responses are ineffective in combating the infection, although a high degree of resistance can be induced through vaccination (Arie & Stewart, 1986). Infected lobsters cease feeding, become lethargic and may exhibit a pinkish colour under the abdomen. When close to death the animals may autotomize one or both chelipeds. Haemolymph samples taken from infected lobsters reveal large numbers of tetrad-forming bacteria under oil immersion. As gaffkaemia can only develop in lobsters with breaks or wounds in the integument, any procedure that fosters exoskeleton damage will increase the risk of disease. The high stocking densities likely to be employed in spiny lobster aquaculture along with stock handling operations could lead to disease outbreaks. Prevention through immunization can reduce the disease risk (Steenbergen & Schapiro, 1974b; Arie & Stewart, 1986; Keith et al., 1992). Disease control with antibiotics, in particular oxytetracycline (OTC), is also effective (Bayer & Daniel, 1987). Novobiocin or amoxicillin could also be used if OTC resistant strains develop (Huang 8z Bayer, 1989). Shell disease

Shell disease, the erosion or degradation of the chitinous exoskeleton through the action of chitinoclastic bacteria or fungi, is one of the most common and widespread crustacean diseases and is frequently seen in homarid and panulirid lobsters (review: Getchell, 1989). It is characterized by the development of exoskeletal lesions of uncertain aetiology. Shell disease of suspected bacterial origin has been observed in Palinuris elephas (Alderman, 1972), as has shell disease caused by a fungal pathogen (Alderman, 1973). Iversen & Beardsley (1976) reported a very low incidence of shell disease (2 in 9000 animals) in the spotted spiny lobster, Panulirus guttatus, but did not detect the disease in P . argus.

Diseases of Spiny Lobsters

591

A survey of 150 lobsters, Punulirus cygnus, collected off the Western Australian coast, also failed to demonstrate typical lesions of shell disease, although minor shell abrasions were seen in 8% of animals examined (Evans, 1987). Whether this apparent low incidence of shell disease in spiny lobsters reflects a high level of host resistance or whether it is a consequence of lack of exposure to predisposing environmental conditions such as inadequate nutrition (Rosemark & Conklin, 1983), prior cuticular damage (Malloy, 1978) or contact with contaminated sediments containing high bacterial loads (Young & Pearce, 1975; Ziskowski et al., 1996) is unknown. Recent observations of outbreaks of shell disease in Jusus edwurdsii held in offshore cages (Geddes pers. comm.) and in P. cygnus held in fibreglass holding tanks in the authors’ laboratories (Fig. 3 1.1) suggest that lack of exposure to adverse environmental conditions is the more likely explanation for the previously observed low incidence of shell disease seen in wild caught spiny lobsters from Western Australia. Shell disease in homarid lobsters is characterized by darkening and softening of the exoskeleton leading ultimately to extensive pitting and necrosis of the cuticle. Gram-negative bacteria including Vibrio spp. have frequently been implicated as causative agents but Aeromonas and Pseudomonas-like species have also been isolated from shell lesions (Malloy, 1978; Roald et al., 1981; Hameed, 1994). Many isolates displayed chitinase activity. Bacteria were also observed to colonize internal portions of exocuticle and endocuticle before the loss of overlying shell layers. No isolates appeared in exclusive association with lesions (Prince et al., 1993). In mild forms shell disease is not fatal, but mortalities can occur in severely affected animals, probably from secondary invaders. Disease outbreaks can cause

Fig. 31.1 Shell disease. Ventral abdomen of Punulirus cygnus showing eroded and blistered margins of telson and uropods.

592 Spiny Lobsters: Fisheries and Culture problems in broodstock animals (Rosemark & Conklin, 1983), and larval and postlarval stock are also susceptible (Fisher et al., 1976). Maintenance of good water quality, provision of adequate nutrition, removal of infected exuvia waste and isolation of infected animals are recommended for the prevention of shell disease in cultured lobsters (Rosemark & Conklin, 1983; Fisher, 1988b). Vibriosis

Vibriosis, a common disease in cultured fish, shellfish and molluscs causes problems in spiny lobster aquaculture. The disease has been observed in aquarium-reared spiny lobsters (Brinkley et al., 1976) and in wild stock lobsters Panulirus spp., held in aquaria (Chong & Chao, 1986; Evans, 1987). Isolates from haemolymph and/or exoskeleton lesions of moribund spiny lobsters include V. parahaemolyticus and V . alginolyticus (Brinkley et al., 1976; Hameed, 1994; Abraham et al., 1996), V. harveyi (Chong & Chao, 1986) and other Vibrio spp. (Abraham et al., 1996). Histopathological changes were also observed in the hepatopancreas, gut and muscle of infected animals (Hameed, 1994; Bower et al., 1994).

31.3.3

Fungal and oomycotic diseases

A wide range of fungal and oomycotic diseases has been observed in marine invertebrates (review: Alderman, 1986). The species pathogenic to spiny lobsters include three genera, Atkinsiella, Fusarium and Lagenidium. A tkinsiella Atkinsiella panulirata is a marine oomycete fungus isolated from cultured phyllosoma of P. japonicus at Shizuoka Prefecture, Japan (Kitancharoen & Hatai, 1995). The fungus exhibited slow growth and the optimal temperature for the fungus was 25°C. Control was most effective with malachite green. Fusarium

The disease conditions attributable to Fusarium sp. occur in both juvenile and adult lobsters (Sindermann, 1990; Brock & Lightner, 1990; Bower et al., 1994). A mycosis of juvenile cultured lobsters, H . americanus, caused a 35% loss over a 12 month period in a closed water system at Woodside, New York (Lightner & Fontaine, 1975). Affected lobsters had ‘black spots’ of various sizes on the exoskeleton and appendages and brownish discoloration of the gills. A pronounced haemocytic response to fungal hyphae was observed in cuticular lesions. The causative organism

Diseases of Spiny Lobsters

593

was shown to be a pigment producing Fusarium sp. Exoskeletal lesions caused by Fusarium solani have also been observed in H . vulgaris (Alderman, 1981). Fungal infection of a spiny lobster species was first demonstrated by Sordi (1958). He reported the isolation of two deuteromycetes, Didymaria palinuri and Fusarium (Ramularia) branchialis from gills of moribund lobsters, Palinurus elephas and H . gammarus, held in an aquarium at Livorno. A similar condition has been reported in P . elephas (Alderman, 1973) and in P. cygnus (McAleer, 1983). In the latter study F. solani was isolated from exoskeletal lesions and used to inoculate healthy lobsters. Superficial and deep injections of the F. solani inoculum caused 100% mortality in treated animals. When the inoculum was applied superficially to traumatized areas of the exoskeleton, typical blackened lesions were observed and fungal hyphae were shown to penetrate the underlying connective tissue and, on occasions, muscle tissue. Fusarium sp. infections are usually focal and result from invasion of previously damaged exoskeletal tissues (Alderman, 1986). The pathogens are ubiquitous and have the capacity to survive on a wide range of substrates. Practical treatments for Fusarium sp. infection of lobsters have not been reported. Lagenidium Lagenidium sp. invades the eggs, larvae and occasionally post-larvae of H . americanus and H . gammarus (Nilson et al., 1976; Rosemark & Conklin, 1983). It has been widely reported but not confirmed in other crustaceans (Bower et al., 1994). Infected larvae become opaque due to tissue invasion and destruction by the fungal mycelium. Complete destruction of larval tissue occurs within 24-48 h of the initial infection and more than 90% of animals in an affected system die within 49-72 h (Nilsen et al., 1976). Infestations of eggs can be controlled with a 5-ppm solution of malachite green, but infected animals are usually beyond treatment (Fisher, 1988~).

31.3.4

Parasitic infections

Microsporidiosis

Of the parasites known to infect spiny lobsters (Table 31.l), a group which may potentially cause stock losses or impaired growth of cultured spiny lobsters is the microsporidans. These protistan parasites infect muscle and other body tissues and cause a gradual weakening of the animal and its eventual death. A brief report of microsporidiosis in the Florida spiny lobster, P. argus, suggests that the disease is endemic in that species and induces mortalities when animals are stressed (Bach & Beardsley, 1976). A microsporidial infection, resembling Ameson sp., also occurs in juvenile (Evans, 1987) and adult (Dennis & Munday, 1994) P. cygnus and P. ornutus from Western Australia. Histological examination of infected muscle tissue showed widespread occurrence of spores within the muscle bundles (Fig. 3 1.2).

594 Spiny Lobsters: Fisheries and Culture

Fig. 31.2 Microsporidiosis in Panulirus cygnus, showing large spore masses infiltrating the tail muscle.

Haematodinium

Dinoflagelates have become an increasing problem in lobster, prawn and in crab fisheries but have not yet been reported in spiny lobsters. Haematodinium-like species infect Norway lobsters ( N . norvegicus) in the west coast of Scotland, Pandalus species in Canada and Alaska (Bower et al., 1994; Appleton & Vickerman, 1998) and crab fisheries in European waters, along the east coast of America and in northern Australia (Bower et al., 1994; Hudson & Lester, 1994; Hudson & Shields, 1994). Cells invade the haemal spaces and infection is fatal to the host (Field et al., 1992; Field & Appleton, 1995). The presence of the dinoflagellate in the haemolymph imparts a ‘bitter’ taste. Nemertine worms

Nemertine worm predation of spiny lobster eggs has been reported by Shields & Kuris (1990) from spiny lobster Panulirus interruptus in southern California and in P. cygnus from Western Australia (Campbell et al., 1989). These worms feed on eggs of spiny lobsters and may cause significant egg loss. Immature worms live in low density on the exoskeleton, including gills, but cause no harm to non-ovigerous lobsters.

Diseases of Spiny Lobsters 31.4

595

Diseases caused by abiotic agents

Abiotic agents are those causal factors for the ‘non-infectious’diseases. Included in this group are the nutritional, environmental (physical and chemical), toxic, metabolic and genetic agents. In farmed animal populations, abiotic factors may be subclinical contributors in outbreaks of infectious disease. Based on our review of the literature, primary diseases or syndromes of spiny lobsters attributable to abiotic agents have seldom been reported. Wada et al. (1994) japonicus) report a cardiac myopathy of unknown aetiology in wild spiny lobsters (P. in the Minami-Izu region of Shizuoka Prefecture, Japan. Affected lobsters had cardiac lesions showing degeneration and necrosis of muscle fibres with haemocyte infiltration. No microorganisms were detected in the cardiac lesions. An affliction designated ‘moult-death syndrome’, of probable nutritional cause, is reported from cultured H . arnericanus (Bowser & Rosemark, 1981) and has been observed in spiny lobsters (J. Booth, pers. comm.). Gas bubble disease is also said to occur in spiny lobsters (J. Booth, pers. comm.). Thus, with the development of spiny lobster farming, more diseases caused by abiotic agents will, in all likelihood, be encountered.

31.5

Conclusions

Reports of diseases are relatively few, probably owing to a lack of extensive study rather than a real absence of diseases. Most disease conditions observed in cultured lobsters are opportunistic infections caused by organisms that are widely distributed in the marine environment. Suboptimal culture conditions and high stocking density are likely to facilitate disease outbreaks by opportunistic pathogens. Careful attention to water quality and diet will assist in preventing such infections. Although several disease conditions of larval and juvenile clawed lobsters have been reported and treatment procedures recommended, little information is available on similar conditions affecting the phyllosoma, puerulus or juvenile stages of spiny lobsters. Further studies are required in this area. Gaffkaemia, a disease condition caused by a primary crustacean pathogen, could result in significant mortalities in cultured spiny lobsters. Vaccination procedures and appropriate chemotherapeutic agents should be tested in spiny lobsters with a view to preventing loss of cultured stock through gaffkaemia.

References Abraham, T.J., Rahman, M.K., & Joseph, M.T.L. (1996) Bacterial disease in cultured spiny lobster, Panulirus homarus (Linnaeus). J. Aquac. Trop.. 11, 187-92.

596 Spiny Lobsters: Fisheries and Culture Acton, R.T., Weinheimer, P.F. & Niedermeier, W. (1973) The carbohydrate composition of invertebrate hemagglutinin subunits isolated from the lobster Panulirus argus and the oyster Crassostrea virginica. Comp. Biochem. Physiol., 448, 185-9. Alderman, D.J. (1972) Diseases in shellfish culture. Proc. 3rd Shellfish Conf. Shellfish Assoc. Gt Britain, pp. 1-125. Cited in Alderman (1973). Alderman, D.J. (1973) Fungal infection of crawfish (Palinurus elephas) exoskeleton. Trans. Br. MYCO~. SOC.,61, 595-7. Alderman, D.J. (1981) Fusarium solani causing an exoskeletal pathology in cultured lobsters, Homarus vulgaris. Trans. Br. Mycol. SOC.,76, 2 6 7 . Alderman, D.J. (1986) Fungal diseases of marine invertebrates. In Pathology in Marine Aquaculture (Ed. by C.P. Vivares, J.F. Bonami & E. Jaspers), pp. 197-201. Spec. Publ. No. 9, European Aquaculture Society, Bredene, Belgium. Alderman, D.J. (1996) Geographical spread of bacterial and fungal diseases of crustaceans. Rev. Sci. Tech. Office Int. Epizooties, 15, 603-32. Aono, H. & Mori, K. (1996) Interaction between hemocytes and plasma is necessary for hemolymph coagulation in the spiny lobster, Panulirus japonicus. Comp. Biochem. Physiol., 113A, 301-5. Appleton, P.L. & Vickerman, K.(1998) In vitro cultivation and developmental cycle in culture of a parasitic dinoflagellate (Hematodinium sp.) associated with mortality of the Norway lobster (Nephrops norvegicus) in British waters. Parasitology, 116, 115-30. Arie, B. & Stewart, J.E. (1986) Stimulation of a high degree of resistance in the lobster, Homarus americanus to the bacterial disease gaffkemia. In Pathology in Marine Aquaculture (Ed. by C.P. Vivares, J.R. Bonami & E. Jaspers), p. 405. Spec. Publ. No. 9, European Aquaculture Society, Bredene, Belgium. Bach, S.D. & Beardsley, G.L. (1976) A disease of the Florida spiny lobsters. Sea Frontiers, 22.52-3. Bachere, E., Mialhe, E., Noel, D., Boulo, V., Morvan, A. & Rodriguez, J. (1995) Knowledge and research prospects in marine mollusc and crustacean immunology. Aquaculture, 132, 17-32. Bauchau, A.G. (1981) Crustaceans. In Invertebrate Blood Cells, Vol. 2 (Ed. by N.A. Ratcliffe & A.F. Rowley), pp. 385420. Academic Press, London, UK. Bayer, R.C. & Daniel, P.C. (1987) Safety and efficacy of oxytetracycline for control of gaffkemia in the American lobster, Homarus americanus. Fish. Res., 5, 71-82. Bobes, R., Diaz., J. & Diaz, E. (1988) Aislamiento e identificacion de Aerococcus viridans var., homari en la langosta Panulirus argus con sintomas de septicemia. Rev. Invest. Mar., 9,97-103. Booth, J.D. (1988) Rock lobster farming in New Zealand: problems and possibilities. Proc. AQUANZ '88 National Conference on Aquaculture, Wellington, 31, 1OW. Bower, S.M., McGladdery, S.E. & Price, I.M. (1994) Synopsis of infectious diseases and parasites of commercially exploited shellfish. Annu. Rev. Fish Dis., 4, 1-199. Bowser, P.R. & Rosemark, R. (1981) Mortalities of cultured lobsters, Homarus americanus, associated with molt death syndrome. Aquaculture, 23, 11-18. Brinkley, A.W., Rommel, F.A. & Huber, T.W. (1976) The isolation of Vibrio parahaemolyticus and related vibrios from moribund aquarium lobsters. Can. J . Microbiol., 22, 315-17. Brock, J.A. & Lightner, D.V. (1990) Diseases of Crustacea: diseases caused by microorganisms. In: Diseases of' Marine Animals, Vol. 111 (Ed. by 0. Kinne), pp. 328-34. Biologische Anstalt Helgoland, Hamburg, Germany. Campbell, A., Gibson, R. & Evans, L.H. (1989) A new species of Carcinomertes (Nemertea, Carcinomeridae) ectohabitants on Panulirus cygnus (Crustacea, Palinuridae) from Western Australia. Zool. J . Linn. Soc., 95, 257-68. Chisholm, J.R.S. & Smith, V.J. (1995) Comparison of antibacterial activity in the hemocytes of different crustacean species. Comp. Biochem. Physiol., llOA, 39-45.

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Chong, Y.C. & Chao. T.M. (1986) Septicemias of marine crabs and shrimp. In The First Asian Fisheries Forum (Ed. by I.L. Maclean, L.B. Dizon & L.V. Hosillos), pp. 331-2. Asian Fisheries Society, Manila, Philippines. Deblock, S., Williams, A. & Evans, L.H. (1990) Contribution a I’ktude des Microphallidae Travassos 1920 (Trematoda). Description de Thulakiotrema genitale n. gen., n. sp., metacercaire parasite de langoustes australiennes. Bull. Mus. Natn. Hist. Nat., Paris, 12, 563-76. Dennis, D.M. & Munday, B.L. (1994) Microsporidiosis of palinurid lobsters from Australian waters. Bull. Eur. Assoc. Fish Path., 14, 16-18. Durliat, M. & Vranckx, R. (1981) Action of various anticoagulants on hemolymphs of lobsters and spiny lobsters. Biol. Bull. Mar. Biol. Lab., Woods Hole, 160, 5548. Evans, E.E., Cushing, J.E., Sawyer, S., Weinheimer, P.F., Acton, R.T. & McNeely, J.L. (1969a) Induced bactericidal response in the spiny lobster Panulirus interruptus. Proc. SOC.Exp. Biol. Med., 132, 111-14. Evans, E.E., Painter, B., Evans, M.L., Weinheimer, P.F. & Acton, R.T. (1968) An induced bactericidin in the spiny lobster, Panulirus argus. Proc. SOC.Exp. Biol. Med., 128, 394-8. Evans, E.E., Weinheimer, P.F., Painter, B., Acton, R.T. & Evans, M.L. (1969b) Secondary and tertiary responses of the induced bactericidin from the West Indian spiny lobster, Panulirus argus. J . Bacteriol., 98, 943-6. Evans, L.H. (1987) Disease Investigations in Fisheries and Aquaculture, pp. 212-14. Annual Report to Western Fisheries Research Committee. WA Department of Fisheries, Australia Field, R.H. & Appleton, P.L. (1995) A Hematodinium-like dinoflagellate infection of the Norway lobster Nephrops norvegicus observations on pathology and progress of infection. Dis. Aquat. Org., 22, 115-28. Field, R.H., Chapman, C.J., Taylor, A.C., Neil, D.M. & Vickerman, K. (1992) Infection of the Norway lobster Nephrops norvegicus by a hematodinium-like species of dinoflagelate on the west coast of Scotland. Dis. Aquat. Org., 13, 1-15. Fisher, W.S. (1988a) Microbial epibionts of lobsters. In Disease Diagnosis and Control in North American Marine Aquaculture, 2nd edn (Ed. by C.J. Sindermann & D.V. Lightner), pp. 243-6. Elsevier, Amsterdam. Fisher, W.S. (1988b) Shell disease of lobsters. In Disease Diagnosis and Control in North American Marine Aquaculture, 2nd edn (Ed. by C.J. Sindermann & D.V. Lightner), pp. 236-9. Elsevier, Amsterdam, The Netherlands. Fisher, W.S. (1988~)Fungus (Lagenidium) disease of lobsters. In Disease Diagnosis and Control in North American Marine Aquaculture, 2nd edn (Ed. by C.J. Sindermann & D.V. Lightner), pp. 247-9. Elsevier, Amsterdam, The Netherlands. Fisher, W.S., Nilson, E.H., Steenbergen, J.F. & Lightner, D.V. (1978) Microbial diseases of cultured lobsters: a review. Aquaculture, 14, 115 4 0 . Fisher, W.S., Rosemark, T.R. & Nilson, E.H. (1976) The susceptibility of cultured American lobsters to a chitinolytic bacterium. Proc. Ann. Mg World Mariculture SOC.,7 , 51 1-20. Fuller, G.M. & Doolittle R.F. (1971a) Studies of invertebrate fibrinogen, I. Purification and characterization of fibrinogen from the spiny lobster. Biochemistry, 10, 1305-1 1. Fuller, G.M. & Doolittle R.F. (1971b) Studies of invertebrate fibrinogen, 11. Transformation of lobster fibrinogen into fibrin. Biochemistry, 10, 1311-18. Getchell, R.G. (1989) Bacterial shell disease in crustaceans: a review. J . Shellfish Res., 8, 1-6. Ghidalia, W., Vendrely, R., Montmory, C., Coirault, Y. & Brouard, M.O. (1981) Coagulation in decapod crustacea. J. Comp. Physiol., 142, 473-8. Gjerde, J. (1 984) Occurrence and characterization of Aerococcus viridans from lobsters, Homarus gammarus L., dying in captivity. J. Fish Dis., 7 , 335-62. Hall, M.R. & Dam, E.H. van (1998) The effects of different types of stress on blood glucose in the giant tiger prawn Penaeus monodon. J . World Aquacult. Soc., 29, 290-300.

598 Spiny Lobsters: Fisheries and Culture Hameed, A S S . (1994) Experimental transmission and histopathology of brown spot disease in shrimp (Penaeus indicus) and lobster (Panulirus homarus). J. Aquacult. Trop., 9, 31 1-22. Hose, J.E., Martin, G.G. & Gerard, A S . (1990) A decapod hemocyte classification scheme integrating morphology, cytochemistry, and function. Biol. Bull. Mar. Biol. Lab., Woods. Hole, 178, 33-45. Huang, C.H. & Bayer, R.C. (1989) Gastrointestinal absorption of various antibacterial agents in the American lobster (Homarus americanus). Prog. Fish-Cult., 51, 95-7. Hudson, D.A. & Lester, R.J.G. (1994) Parasites and symbionts of wild mud crabs Scylla serrata (Forskal) of potential significance in aquaculture. Aquaculture, 120, 183-99. Hudson, D.A. & Shields, J.D. (1994) Hematodinium australis n. sp., a parasitic dinoflagellate of the sand crab Portunus pelagicus from Moreton Bay, Australia. Dis. Aquat. Org., 19, 109-19. Imai, T., Goto, R., Kittaka, J. & Kamiya, H. (1994) Lectins of the rock lobster, Jasus novaeholande haemolymph. Crustaceana, 67, 121-30. Iversen, E.S. & Breardsley, G.L. (1976) Shell disease in crustaceans indigenous to South Florida. Prog. Fish-Cult., 38, 195-6. Jussila, J., Jago, J., Tsvetnenko, E., Dunstan, R. & Evans, L.H. (1998) Total and differential haemocyte counts in western rock lobster (Panulirus cygnus George) under post-harvest stress. Mar. Freshwat. Res., 48,863-7. Keith, I.R., Paterson, W.D., Airdrie, D. & Boston, L.D. (1992) Defence mechanisms of the American lobster (Homarus americanus): vaccination provided protection against gaffkemia infections in laboratory and field trials. Fish Shelpsh Immunol., 2, 109-19. Kitancharoen, N. & Hatai, K. (1995) A marine oomycete Atkinsiella panulirata sp. nov. from phyllosoma of spiny lobster, Panulirus japonicus. Mycoscience, 36, 97-104. Lanz Mendoza, H. & Faye, I. (1996) Immunoglobulin superfamily proteins in invertebrates. In New Directions in Invertebrate Immunology (Ed. by K. Soderhall, S. Iwanaga & G.R. Vasta), pp. 285-302. SOS Publications, New Haven, NJ, USA. Lightner, D.V. (1988) Diseases of cultured penaeid shrimp and pranws. In Diseuse Diagnosis and Control in North American Marine Aquaculture, 2nd edn (Ed. by C.J. Sindermann & D.V. Lightner), pp. 8-127. Elsevier, Amsterdam, The Netherlands. Lightner, D.V. & Fontaine, C.T. (1975) A mycosis of the American lobster, Homarus americanus, caused by Fusarium sp. J. Invertebr. Pathol., 25, 239-45. McAleer, R. (1983) Black shell disease of the western rock lobster caused by Fusarium solani. In Proc. 8th Int. SOC.Hum. Anim. Mycol., pp. 378-82. Massy University, Palmerston North, New Zealand. Malloy, S.C. (1978) Bacteria induced shell disease of lobsters (Homarus arnericanus). J. Wildl. Dis., 14, 2-10. Moore, A. & Li, M.F.(1985) Examination of necrotic and swollen antenna1 glands from American lobsters (Homarus americanus). Annu. Meet. Aquaculture Association of Canada & Fish Health Workshop, Nova Scotia. Nilson, E.H., Fisher, W.S. & Schleser, R.A. (1976) A new mycosis of larval lobster (Homarus americanus). J. Invertebr. Pathol., 27, 177-83. Nyhlen, L. & Unestam, T. (1980) Wound reactions and Aphanomyces astaci growth in crayfish cuticle. J. Invertebr. Pathol., 36, 187-97. Prince, D.L., Bayer, R.C. & Loughlin, M. (1993) Etiology and microscopy of shell disease in impounded American lobsters, Homarus americanus. Bull. Aquacult. Assoc. Can., 4, 87-9. Ratcliffe, N.A., Rowley, A.F., Fitzgerald, S.W. & Rhodes, C.P. (1985) Invertebrate immunity. Basic concepts and recent advances. Int. Rev. Cytol., 97, 183-350. Roald, S.O., Aursjo, J. & Hastein, T. (1981) Occurrence of shell disease in lobsters, Homarus gammarus (L.), in the southern part of the Oslofjord, Norway. FiskDir. Skr. Ser. Havunders, 17, 153-60.

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Roch, P. (1999) Defense mechanisms and disease prevention in farmed marine invertebrates. Aquaculture, 172, 12546. Rosemark, R. & Conklin, D.E. (1983) Lobster pathology and treatments. In CRC Handbook of Mariculture, Vol. I , Crustacean Aquaculture (Ed. by J.P. McVey), pp. 371-7. CRC Press, Boca Raton, FL, USA. Schapiro, H.C., Mathewson, J.H., Steenbergen, J.F., Kellogg, S., Ingram, C., Nierengarten, G . & Rabin, H. (1974) Gaffkemia in the California spiny lobster, Panulirus interruptus: infection and immunization. Aquaculture, 3, 403-8. Shields, J.D. & Kuris, A.M. (1990) Carcinonemertes wickhami n. sp. (Nemertea), a symbiotic egg predator from the spiny lobster Panulirus interruptus in southern California, with remarks on symbiont-host adaptations. Fish. Bull., 88, 279-87. Sindermann, C.J. (1977) Disease Diagnosis and Control in North American Marine Aquaculture. Elsevier Scientific, Amsterdam, The Netherlands, 329 pp. Sindermann, C.J. (1 990) Principal Diseases of Marine Fish and Shel&sh, 2nd edn. Vol. 2, Diseases of Marine Shellfish. Academic Press, San Diego, USA, 516 pp. Smith, V.J. (1991) Invertebrate immunology: phylogenetic, ecotoxicological and biomedical implications. Comp. Haem. Int., 1, 61-76. Soderhall, K. (1 992) Biochemical and molecular aspects of cellular communication in arthropods. BUN. ZOO^., 59, 141-51. Soderhall, K. & Ajaxon, R. (1982) Effects of quinones and melanin on mycelial growth of Aphanomyces spp. and extracellular protease of Aphanomyces astaci, a parasite on crayfish. J. Invertebr. Pathol., 39, 105-9. Soderhall, K. & Smith, V.J. (1986) The prophenoloxidase activating system: the biochemistry of its activation and role in arthropod cellular immunity with special reference to crustaceans. In Immunity in Invertebrates (Ed. by M. Brehelin), pp. 208-23. Springer, Berlin, Germany. SGderhall, K., Cerenius, L. & Johansson, M.W. (1996) The prophenoloxidase activating system in invertebrate immunology. In New Directions in Invertebrate Immunology (Ed. by K. Soderhall, S. Iwanaga & G.R. Vasta), pp. 229-53. SOS Publications, New Haven, NJ, USA. Sordi, M. (1958) Micosi dei Crostacci decapodi marini. Riv. Parassitol., 19, 131-7. Steenbergen, J.F. & Schapiro, H.C. (1974a) Gaffkemia in California spiny lobsters. In Proc. Ffth Ann. M g World Mariculture SOC.(Ed. by J.W. Avault, Jr), pp. 13943. Louisiana State University, Baton Rouge, USA. Steenbergen, J.F. & Schapiro, H.C. (1974b) Active immunity to gaffkemia in lobsters. In Proc. Ffth Annu. Mg World Mariculture SOC.(Ed. by J.W. Avault, Jr), pp. 145-7. Louisiana State University, Baton Rouge, USA. Stewart, J.E. (1975) Gaffkemia, the fatal infection of lobsters (genus Homarus) caused by Aerococcus viridans (var.) homari: a review. Mar. Fish. Rev., 37, 20-4. Stewart, J.E. (1980) Diseases. In The Sio/ogy and Management oflobsters, Vol. 1 (Ed. by J.S. Cobb & B.F. Phillips), pp. 30142. Academic Press, New York, USA. Stewart, J.E. (1984) Lobster diseases. Helgolander Wiss. Meeresunters, 37, 243-54. Sugumaran, M. (1996) Role of insect cuticle in immunity. In New Directions in Invertebrate Immunology (Ed. by K. Soderhall, S. Iwanaga, & G.R. Vasta), pp. 355-74. SOS Publications, New Haven, NJ, USA. Tyler, A. & Metz, C.B. (1945) Natural heteroagglutinins in the serum of the spiny lobster, Panulirus interruptus, I. Taxonomic range of activity, electrophoretic and immunizing properties. J . Exp. Zool., 100, 387406. Tyler, A. & Scheer, B.T. (1945) Natural heteroagglutinins in the serum of the spiny lobster, Panulirus interruptus, 11. Chemical and antigenic relation to blood proteins. Biol. Bull. Mar. Biol. Lab., Woods Hole, 89, 193-200.

600 Spiny Lobsters: Fisheries and Culture Ueda, R., Sugita, H. & Deguchi, V. (1990) The serum bactericidal activity: a possible indicator as crustacean health conditions. In Proceedings of the Fourth Pacific Congress on Marine Science Technology, Tokyo, pp. 333-40. Ueda, R., Sugita, H. & Deguchi, V. (1991) Naturally occurring agglutinin in the hemolymph of Japanese coastal crustacea. Nippon Suisan Grakkaishi, 57, 69-78. Ueda, R., Sugita, H. & Deguchi, V. (1994) Bactericidal activities of the hemolymph of the Japanese spiny lobster, Panulirus japonicus (Decapoda, Panuliridae) Crustaceana, 67, 256-8. Unestam, T. & Nylund, J.E. (1972) Blood reactions in vitro in crayfish against a fungal parasite Aphanomyces astaci. J. Invertebr. Pathol., 19, 94-106. Wada, S., Takayama, A., Hatai, K., Shima, Y. & Fushimi, H. (1994) A pathological study on cardiac disease found in spiny lobsters. Fish. Sci., 60, 129-31. Weinheimer, P.F., Acton, R.T., Sawyer, S. & Evans, E.E. (1969a) Specificity of the induced bactericidins of the West Indian spiny lobster, Panulirus argus. J. Bacteriol., 98, 947-8. Weinheimer, P.F.,Evans, E.E., Acton, R.T. & Painter, B. (1969b) Induced response of the lobster, Panulirus argus. Fedn Proc., Fedn Am. SOCSExp. Biol., 28, 752. Weinheimer, P.F., Evans, E.E., Stroud, R.M. Acton, R.T. & Painter, B. (1969~)Comparative immunology: natural hemolytic system of the spiny lobster, Panulirus argus. Proc. SOC.Exp. Biol. Med., 130, 322-6. Wiik, R., Egidius, E. & Goksoyr, J. (1987) Screening of Norwegian lobsters Homarus gammarus for the lobster pathogen Aerococcus viridans. Dis. Aquat. Org., 3, 97-100. Young, J.S. & Pearce, J.B. (1975) Shell disease in crabs and lobsters from New York Bight. Mar. Pollut. Bull., 6, 101-5. Ziskowski, J., Spallone, R., Kapareiko, D., Robohm, R., Calabrese, A. & Pereira, J. (1996) Shell disease in American lobster (Homarus americanus) in the offshore, northwest-Atlantic region around the 106-mile sewage-sludge disposal site. J . Mar. Environ. Eng., 3, 247-71.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 32

Functional Morphology of the Digestive System

s. MIKAMI

Australian Fresh Corporation, c/o QDPI Bribie Island Aquaculture Research

Centre. P.O. Box 2066, Bribie Island, Queensland 4507, Australia

F. TAKASHIMA

Tokyo University of Fisheries, 4-5-7 Konnan. Minato-ku, Tokyo

108-8477, Japan

32.1

Introduction

Diet is an important factor affecting survival of phyllosomas and juveniles of lobster species, and one of the key issues in successful lobster aquaculture. Observation of the functional morphology of the digestive system can indicate the suitability of particular food types and contribute to better understanding of the requirements for larval and growout diets. Knowledge derived from the study on the digestive system can also be used as an indication of whether developed diets are properly utilized by phyllosomas and juveniles. There are many publications on the functional aspects of the digestive system of decapod crustaceans, with reviews of these studies being made, for example, by Conklin (1980), Phillips et al. (1980), Dall & Moriarty (1983), McLaughlin (1983), Factor (1989) and Dall et al. (1990). Several studies have been published on the digestive system in the adult spiny lobster, with the most notable study by Paterson (1968) on anatomy of Jasus lalandii. There have also been several studies on morphology of the gut system in phyllosomas, including Nishida et al. (1990) on morphological development of the mouthparts and foregut of phyllosoma, puerulus and juvenile Jasus edwardsii, Wolfe & Felgenhauer (1991) on ontogeny of the mouthparts and foregut of phyllosoma, puerulus and juvenile Panulirus argus, Mikami et al. (1994) on cytology of the digestive system of phyllosoma Panulirus japonicus and Macmillan et al. (1997) on the morphology of the digestive tract of phyllosoma J . edwardsii. A summary is presented of the current knowledge of the digestive system of adult and larval lobsters, with information from the authors’ own studies on the functional morphology of the digestive system of phyllosomas of the palinurid lobster P . japonicus and the scyllarid lobster Zbacus ciliatus.

601

602 Spiny Lobsters: Fisheries and Culture 32.2

Functional aspects of the adult digestive system

Food items collected by the second and third pereiopods or the third maxillipeds are carried into the mouthparts, where they may be sorted and shredded by setose endites of the inner mouthparts, eventually reaching the mandibles, which have welldeveloped incisor and molar processes and are strongly calcified. Thus, considerable pre-ingestion mechanical processing may occur before the finely divided food particles pass into the digestive tract (Phillips et al., 1980; Factor, 1989). The foregut proventriculus (stomach) is lined with chitinous cuticle because of its ectodermal origin (Shiino, 1950). The proventiculus is morphologically divided into two principal chambers, an anterior (cardiac) chamber and a posterior (pyloric) chamber, separated by the cardiopyloric valve. The anterior chamber is distensible and contains a series of calcified ossicles, which are capable of grinding ingested food into small particles. The structure of the extensive and massive gastric mill of spiny lobsters has been illustrated for serval species, including Palinurus elephas (P. vulgaris used in Patwardhan, 1935), Panulirus polyphagus (George et al., 1955), J. lalandii (Fielder, 1965; Paterson, 1968), P. argus (Maynard & Dando, 1974) and J. edwardsii (J. novaehollandiae used in Suthers & Anderson, 1981). A filtering mechanism develops dorsally in the smaller posterior chamber and functions to sort out the smaller food particles. A basic model of the circulation of food particles and digestive gland fluids in the decapod (including Panulirus cygnus) proventriculus has been described and illustrated by Dall & Moriarty (1983). In addition, Suthers & Anderson (1981) have shown the sequence of movements of the gastric mill in relation to food circulation and masticatory action in the scyllarid lobster Zbacus peronii. The pattern of movement of particles and fluid in the proventriculus of spiny lobsters agrees with these descriptions. Food particles too large to pass through the cardiopyloric valve are directed dorsally, reprocessed by the gastric mill and mixed with enzymes secreted by the midgut gland. Small food particles and liquids pass through the cardiopyloric valve and enter the posterior chamber; here they flow over a chitinous ridge bearing spins and setae, and are then filtered by the filter-press developed dorsally in this chamber. Thus, only minute food particles and liquids may continue by this route to enter the midgut gland, and any material not able to pass through the filter-press is returned into the anterior chamber through the dorsal channel and mixed with food materials which previously could not pass through the cardiopyloric valve. Here, because four valves (dorsal, ventral, and a pair of lateral valves) extend across the lumen of the midgut from the posterior chamber, indigestible materials in the midgut gland are evacuated into the lumen of the midgut without contamination from the flesh minute particles and liquids in the posterior chamber. Although Dall (1967) has reported that up to 12% of ''C-labelled nutrients ingested by the greasyback prawn Metapenaeus bennettae passed into the epithelial cells of the proventriculus, there has been no description of absorption of the food materials through the proventriculus wall in lobsters.

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603

The midgut gland, also called the digestive gland or hepatopancreas, extends on either side of the proventriculus in the cephalothrax of the lobster. The term ‘midgut gland’ is used in the present study, following the terminology of van Wee1 (1974). The midgut gland comprises a large number of blind tubules consisting of an inner epithelium consisting of four cytologically and functionally different cell types, surrounded by circular and longitudinal muscle tissue. The epithelial cell types are usually referred to as E-cells, F-cells, B-cells and R-cells (Gibson & Barker, 1979). Although there are indications that functions and cytological development of these cells may differ among decapod species, the major structure and function of each cell type in the spiny lobster correspond to those described for the freshwater crayfish Procambarus clarkii as described by Loizzi (1971) and the scyllarid lobster Thenus orientalis as described by Johnston et al. (1998). E-cells occur in the proximal ends of the tubules and are characterized by being undifferentiated and unspecialized, undergoing active mitosis. F-cells contain a large volume of rough endoplasmic reticular, small spherical mitochondria and large Golgi systems, synthesize digestive enzymes and sequester them in a supranuclear vacuole which enlarges by pinocytotic intake of luminal nutrients and fluids. B-cells, which appear to develop from F-cells, are characterized by a large vacuole, and provide secretory action which involves pinching off the apical complex followed by extrusion of the enzyme rich vacuole contents. R-cells absorb luminal nutrients, mainly by molecular transport, and they store and metabolize glycogen and lipids. Travis (1955) has shown that in P . argus the midgut epithelium tubules consist of two major types of cells, secretory and absorptive cells. It is possible that she did not distinguish between all categories of cells present, her secretory cells corresponding to B-cells, and the absorptive cells probably including E-, F- and R-cells as described above. The midgut gland also has several functions other than digestion and absorption. For instance, Miyawaki & Tanoue (1962) found that in P . clarkii, there are two metal-containing cell types, one of which accumulates iron (Fe) and the other copper (Cu), with the roles of these cells being calcium metabolism and absorption, and storage of lipid respectively. The role of the midgut gland in storage, metabolism and detoxification of a number of metals, and its role in excretion, are still unclear. Indigestible material and unfiltered particles from the proventriculus are moved by peristalsis of the lumen of the midgut into the hindgut. The hindgut is ectodermal in origin and hence is lined by cuticle. The longitudinal slit on the ventral surface of the telson is controlled by the surrounding radial sphincter muscle (Phillips et al., 1980). There is no report of absorption of nutrients through the hindgut.

32.3

Functional aspects of the phyllosoma digestive system

The functional development of the digestive tract has not received much attention in the larvae of any decapod species, and indeed is little known in the phyllosomas of lobster species. The only published studies of this feature in spiny lobster

604 Spiny Lobsters: Fisheries and Culture phyllosomas are those by Mitchell (1971) for P . interruptus, Nishida et al. (1990) and Wolfe & Felgenhauer (1991) for P . argus, Mikami et al. (1994) for P . japonicus and Macmillan et al. (1997) for J . edwardsii. Because adult palinurid and scyllarid lobsters are predatory and scavenging benthic macrophages (Suthers & Anderson, 1981), whereas the larvae are planktonic microphages, it is reasonable to suppose that the feeding mechanism and the structure of the digestive system in phyllosoma stages must differ from those of the adults. Although the phyllosomal digestive tract is divided into three regions (the foregut, midgut and hindgut) in a manner homologous with that of the adult, details of the structure and function of the larval digestive system do indeed differ from those of the adults (Fig. 32.1). Although the third maxillipeds of adults have some masticatory function (Paterson, 1968; Suthers & Anderson, 1981), there is no grinding structure or action in the phyllosomal maxillipeds, their actions being solely related to food manipulation. This functional limitation has also been observed by others studying larviculture (e.g. Dotsu et al., 1966; Batham, 1967; Lesser, 1974). The structure of the inner mouthparts of the phyllosoma also differs from that of the adult lobster. In phyllosomas, the large labrum and pared paragnaths are well developed, forming a semienclosed chamber. They control the amount of material ingested into this chamber, where mastication by the action of the well-developed incisor-like process of the mandibles occurs (Nishida et al., 1990; Mikami et al., 1994). Furthermore, on the surface of the paragnaths, there are openings which may connect to underlying tegumental glands probably involved in secreting mucoid material. These secretions mix with the food particles as they are masticated by the mandibles (Mikami et al., 1994). Similar structures were also reported by Barker & Gibson (1977) following histological observations on the adult clawed lobster Homarus gammarus, where mucoid materials are secreted from oesophageal tegumental glands through openings in the oesophageal lumen. The phyllosomal proventriculus differs in shape from that of nephropid larvae (Hinton & Corey, 1978; Factor, 1981) and from that of adult lobsters. There is no cardiopyloric valve in the scyllarid phyllosomas (I. ciliatus) (Mikami & Takashima, 1993) and it does not develop in the palinurid phyllosoma ( P . argus) (Wolfe & Felgenhauer, 1991). The phyllosomal proventriculus therefore consists of a simple straight tubule, which is not divided into principal anterior and posterior chambers. In addition, the chitinous walls are uncalcified and consequently lacking any gastric mills (Nishida et al., 1990; Wolfe & Felgenhauer, 1991; Mikami & Takashima, 1993), but setae, spines, grooves and the filter-press (except in the newly hatched phyllosoma stage) are well developed. It is clear that the phyllosomal proventriculus functions mainly to filter the food particles previously masticated by the mouthparts. There is no grinding, no mixing of the particles with enzymes from the midgut gland, and no storage of the particles, which are important functions in the adult proventriculus.

Functional Morphology of the Digestive System

605

Fig. 32.1 (a) Drawing of the phyllosomal digestive tract of the spiny lobster Panufirus japonicus. A, mouthparts; B, oesophagus; C , proventriculus; D, midgut gland; E, midgut; F, hindgut. Scale: total body length, from between eyestalks to the end of tail, is 2.0 mm. (b) Phyllosomal digestive tract of the slipper lobster Ibacus ciliutus. A, mouthparts; B, proventriculus; C , midgut gland; D, midgut; E, hihdgut. Scale, total body length is 4.57 mm. (c) Diagram of the digestive tract of an adult spiny lobster. ACP, anterior chamber of proventriculus; AN, anus; FP, filter-press of proventriculus; HG, hindgut; MG, midgut; MGG, midgut gland; OES, oesophagus; PCP, posterior chamber of proventriculus. Scale bar, 1 mm.

606 Spiny Lobsters: Fisheries and Culture The morphology of both the mouthparts and the proventriculus suggests that they are adapted for handing and feeding soft and moist (high water content) food masses such as fish larvae, brine shrimp and mussel gonad only. In fact, several reports on culture of phyllosomas have shown that these soft diets can be used successfully in larviculture (e.g. Inoue, 1978; Takahashi 8t Saisho, 1978; Kittaka & Kimura, 1989; Yamakawa el al., 1989). In addition, these observations support reports suggesting that scyllarid (not palinurid) phyllosomas found associated with medusa may feed on the tissues of these medusa (Shojima, 1963; Thomas, 1963; Sims & Brown, 1968; Herrnkind et al., 1976; Phillips & Sastry, 1980). The phyllosomal midgut gland is the most obvious structure in the cephalothorax, and is composed of a series of caecae containing four cell types (E-, F-, B- and Rcells) as noted earlier for adult decapods (Fig. 32.2). E-cells are the smallest of the four cell types and occur in the proximal ends of the midgut gland tubules. Their main characteristics are that they are undifferentiated and unspecialized cells undergoing active mitosis. They develop rough endoplasmic reticulum and smooth endoplasmic reticulum, small spherical mitochondria and large Golgi apparatus. Fcells are presumed to play a role in secreting and storing digestive enzymes owing to their well-developed rough endoplasmic reticulum. Usually, F-cells are strongly basophilic because of the large number of free and membrane-bound ribosomes in their cytoplasm. B-cells are readily recognizable in histological investigations because they contain a huge blister-like vacuole near the proximal cell border. They have a brush border with a sparse enteric coat, small accumulations of vacuoles, pinocytotic vesicles, small mitochondria and bundles of microtubules. The nucleus of mature B-cells is compressed near the proximal cell border because of the large blister-like vacuole. R-cells are the most abundant cell type in the midgut gland and characteristically contain a large number of vacuoles after feeding. Their possible function is the absorption of digested nutrients and the storage and metabolism of lipids and glycogen, which are present as globules in the cytoplasm. The microvillus of R-cells is slightly longer and bears a surface enteric coat consistently thicker than that of F-cells. Apparently, the final phase of digestion occurs intracellularly in R-cells. However, lipid-rich globules in the R-cells disappear after about 8-12 h of starvation, suggesting little ability for long-term storage of digested nutrients in R-cells of phyllosomal midgut gland. The developmental sequence of these four cell types in the phyllosomal midgut gland has not yet been clarified. The lumen of the midgut is composed of a single epithelial cell layer. The structure of these cells is similar to that of R-cells in the midgut gland. Because the larval proventriculus lacks specialization for grinding and storage of food particles, nutritionally rich materials are ingested directly into the lumen of the midgut and discharged from the anus. In this process, many globules appear in cells in the anterior portion of the midgut. Absorption of nutrients probably occurs, not only in the midgut gland, but also in this anterior lumen of the midgut. The hindgut is lined with chitinous cuticle and does not appear to have any digestive function in the ph yllosomas.

Functional Morphology of the Digestive System

601

Fig. 32.2 Illustrations of the phyllosomal midgut gland epithelial cells of the spiny lobster Punulirus juponicus. (a) F-cell; (b) B-cell; (c) R-cell; (d) E-cell. bv, blister-like vacuole; g, Golgi apparatus; lmg, lumen of midgut gland; lrg, lipid-rich globule; m, mitochondria; n, nucleus; pv, pinocytotic vesicle; rer, rough endoplasmic reticulum; ser, smooth endoplasmic reticulum.

Dramatic morphological changes occur in the digestive system, including the mouthpart, when phyllosomas metamorphose into the puerulus stage. With development of the cardiopyloric valve from folds in the proventiculuar wall during the puerulus stage, the anterior and posterior chambers become differentiated, and the shape of the proventriculus becomes similar to that in the adult lobster (Wolfe 8t

608 Spiny Lobsters: Fisheries and Culture

Felgenhauer, 199 1). These changes coincide with the lifestyle transition from pelagic phyllosomas to benthic juveniles, with consequent change in diet. Hinton & Corey (1978) similarly found that the metamorphosis of the mouthparts and gastric structure coincided with the change from the planktonic existence of the larvae to the benthic existence of adults of H . americanus. In contrast, Nishida et al. (1990) have reported that the mouthparts of the puerulus of J. edwardsii are underdeveloped, suggesting that pueruli do not have to feed during their existence. Indeed, pueruli of P . japonicus have been cultured routinely without feeding (Fisheries Research Institute of Mie, Japan Sea-Farming Association, pers. comm.). The absence of feeding during the puerulus stage has been also proved biochemically by Lemmens (1994) in the Western rock lobster P . cygnus, and the fat bodies are storage sites of nutrients and provide a source of metabolic energy during the puerulus stage (Takahashi et al., 1994). Although morphological changes of larval mouthparts and of the proventriculus have been examined, functional and nutritional changes in the midgut gland following metamorphosis are still unclear. Future study is needed in functional aspects of the larval digestive system, especially the midgut gland and its relationship to diet and nutritional requirements, for successful aquaculture of lobsters.

References Barker, P.L. & Gibson, R. (1977) Observations on the feeding mechanism, structure of the gut, and digestive physiology of the European lobster Homarus gammarus (L.) (Decapoda: Naphropiae). J. Exp. Mar. Biol. Ecol., 26, 297-324. Batham, E.J. (1967) The first three larval stages and feeding behaviour of phyllosoma of the New Zealand palinurid crayfish Jasus edwardsii (Hutton 1875). Trans. R. Soc. N.Z. Zool., 9, 53-64. Conklin, D.E. (1980) Nutrition. In The Biology and Management of Lobsters, Vol. 1 (Ed. by J.S. Cobb & B.F. Phillips), pp. 277-300. Academic Press, New York, USA. Dall, W. (1967) The functional anatomy of the digestive tract of a shrimp Metapenaeus bennettae Racek & Dall (Crustacea: Decapoda: Penaeidae). Aust. J. Zool., 15, 699-714. Dall, W. & Moriarty, D.J.W. (1983) Functional aspects of nutrition and digestion. In The Biology of Crustacea, Vol. 5 (Ed. by L.H. Mantel), pp. 215-61. Academic Press, New York, USA. Dall, W., Hill, B.J., Rothlisberg, P. & Staples, D.J. (1990) Morphology. In Advances in Marine Biology, Vol. 27, The Biology of the Penaeidae (Ed. by J.H.S. Blaxter & A.J. Southward), pp. 7-54. Academic Press, London, UK. Dotsu, Y.,Seno, K. & Inoue, S. (1966) Rearing experiments on early phyllosomas of Ibacus ciliatus (von Siebold) and I. Novemdentatus Gibbes (Crustacia: Reptantia). Bull. Fac. Fish. Nagasaki Univ., 21, 181-94. Factor, J.R. (1981) Development and metamorphosis of the digestive system of larval lobsters, Homarus americanus (Decapoda: Nephropidae). J. Morph., 169, 22542. Factor, J.R.(1989) Development of the feeding apparatus in decapod crustaceans. In Crustacean Issues 6, Functional Morphology of Feeding and Grooming of Selected Crustacea (Ed. by B.E. Felgenhaure & L. Watling), pp. 185-203. A.A. Balkema, Rotterdam, The Netherlands. Fielder, D.R. (1965) The spiny lobster Jasus lalandii in South Australia 111. Food, feeding and locomotory activity. Ausr. J . Mar. Freshwat. Res., 16, 351-67.

Functional Morphology of the Digestive System

609

George, C.J., Reuben, N. & Muthe, P.T. (1955) The digestive system of Panulirus polyphagus. J . Anim. Morph. Physiol., 2 14-27. Gibson, R. & Barker, P.L. (1979) The decapod hepatopancreas. Oceanogr. Mar. Biol. Annu. Rev., 17, 285-348. Herrnkind, W., Halusky, J. & Kanciruk, P. (1976) A further note on phyllosoma larvae associated with medusa. Bull. Mar. Sci., 26, 110-12. Hinton, D. J. & Corey, S. (1978) The mouthparts and digestive tract in the larval stages of Homarus americanus. Can. J . Zool., 57, 1413-23. Inoue, M. (1978) Studies on the cultured phyllosoma larvae of the Japanese spiny lobster, Panulirus japonicus I. Morphology of the phyllosoma. Bull. Jpn. SOC.Sci. Fish., 44,457-75. Johnston, D.J., Alexander, C.G. & Yellowlees, D. (1998) Epithelial cytology and function in the digestive gland of Thenus orientalis (Decapoda: Scyllaridae). J . Crust. Biol., 18, 271-8. Kittaka, J. & Kimura, K. (1989) Culture of the Japanese spiny lobster Panulirusjaponicus from egg to juvenile stage. Nippon Suisan Gakkaishi, 55, 963-70. Lemmens, J.W.T.J. (1994) Biochemical evidence for absence of feeding in puerulus larvae of the Western rock lobster Panulirus cygnus (Decapoda: Palinuridae). Mar. Biol., 118, 383-91. Lesser, J.H.R. (1974) Identification of early larvae of New Zealand spiny and shovel-nosed lobsters (Decapoda, Palinuridae and Scyllaridae). Crustaceana, 27, 257-77. Loizzi, R.F. (1971) Interpretation of crayfish hepatopancreatic function based on fine structural analysis of epithelial cell lines and muscle network. 2. Zellforsch.. 113, 42WO. McLaughlin, P.A. (1983) Internal anatomy. In The Biology of Crustacea, Vol. 5 (Ed. by L.H. Mantel), pp. 1-52. Academic Press, New York, USA. Macmillan, D.L., Sandow, S.L., Wikeley, D.M. & Frusher, S. (1997) Feeding activity and the morphology of the digestive tract in stage-I phyllosoma larvae of the rock lobster Jasus edwardsii. Mar. Freshwat. Res., 48, 19-26. Maynard, D.M. & Dando, M.R. (1974) The structure of the stomatogastric neuromuscular system in Callinectes sapidus, Homarus americanus and Panulirus argus (Decapoda: Crustacea). Phil. Trans. R. Soc., 268B, 161-220. Mikami, S . & Takashima F. (1993) Development of the proventriculus in larvae of the slipper lobster Ibacus ciliatus (Decapoda, Scyllaridae). Aquaculture, 116, 199-217. Mikami, S., Greenwood, J. & Takashima, F. (1994) Functional morphology and cytology of the phyllosomal digestive system of Ibacus ciliatus and Panulirus japonicus (Decapoda, Scyllaridae and Palinuridae). Crustaceana, 67, 212-25. Mitchell, J.R. (197 1) Food preferences, feeding mechanisms, and related behaviour in phyllosoma larvae of California spiny lobster, Panulirus interruptus (Randall). MSc. thesis, San Diego State College, San Diego, USA. Miyawaki, M. & Tanoue, S. (1962) Electron microscopy of the hepatopancreas in the crayfish, Procambarus clarkii. Kumamoto J. Sci., 5, 1 4 . Nishida, S., Quigley, B.D., Booth, J.D., Nemoto, T. & Kittaka, J. (1990) Comparative morphology of the mouthparts, and foregut of the final-stage phyllosoma, puerulus, and postpuerulus of the rock lobster Jasus edwardsii (Decapoda: Palinuridae). J . Crust. Biol., 10, 293-305. Paterson, N.F. (1968) The anatomy of the Cape rock lobster Jams lalandii (H. Milne Edwards). Annl. S. Afr. Mus., 51, 1-232. Patwardhan, S.S. (1935) On the structure and mechanism of the gastric mill in Decapoda. IV. The structure of the gastric mill in Reptantous Macrura. Proc. Ind. Acad. Sci. Sect. B, lB, 414-22. Phillips, B.F. & Sastry, A.N. (1980) Larval ecology. In The Biology and Management of Lobsters, Vol. 2 (Ed. by J.S. Cobb & B.F. Phillips), pp. 11-57. Academic Press, New York, USA. Phillips, B.F., Cobb, J.S. & George, R.W. (1980) General biology. In The Biology and Management of Lobsters, Vol. 1 (Ed. by J.S. Cobb & B.F. Phillips), pp. 1-82. Academic Press, New York, USA.

610 Spiny Lobsters: Fisheries and Culture Shiino, N. (1950) Studies on the embryonic development of Panulirus japonicus (V. Sievold). J . Fuc. Fish. Pref. Univ. Mie-Tsu, 1, 1-168. Shojima, Y . (1 963) Scyllarid phyllosomas’ habit of accompanying the jelly-fish (preliminary report). Bull. Jpn. SOC.Scient. Fish., 29, 349-53. Sims, H.W. & Brown, C.L. (1968) A giant scyllarid phyllosoma larvae taken north of Bermuda (Palinrudae). Crustaceana Suppl., 2, 80-2. Suthers, I.M. & Anderson, D.T. (1981) Functional morphology of mouthparts and gastric mill of Zbacus peronii (Leach) (Palinura: Scyllaridae). Aust. J. Mar. Freshwat. Res., 32, 9 3 1 4 . Takahashi, M. & Saisho. T. (1978) The complete larval development of the scyllarid lobster, Ibacus ciliatus (von Siebold) and Ibacus novemdentatus Gibbes in the laboratory. Mem. Fac. Fish. Kagoshiima Univ., 27, 305-53. Takahashi, Y., Nishida, S . & Kittaka, J. (1994) Histological characteristics of fat bodies in the puerulus of the rock lobster Jams edwardsii (Hutton, 1975) (Decapoda, Palinuridae). Crustaceana, 66, 3 18-25. Thomas, L.R. (1963) Phyllosoma larvae associated with medusae. Nature, Lond., 198, 208. Travis, D.F. (1955) The moulting cycle of the spiny lobster, Panulirus argus Latreilli. 11. Pre-ecdysial histological and histochemical changes in the hepatopancreas and integumental tissues. Biol. Bull. Mar. Biol. Lab., Woods Hole, 108, 88-112. Weel, van, P.B. (1974) Hepatopancreas? Comp. Biochem. Physiol., 47A, 1-9. Wolfe, S.H. & Felgenhauer, B.E. (1991) Mouthpart and foregut ontogeny in larval, postlarval, and juvenile spiny lobster, Panulirus argus Latreille (Decapoda, Palinuridae). Zool. Scripta, 20, 5775. Yamakawa, T., Nishimura, M., Matsuda, H., Tsujigado, A. & Kamiya, N. (1989) Complete larval rearing of the Japanese spiny lobster Panulirus japonicus. Nippon Suisan Gakkaishi, 55, 745.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 33

Nutrition and Food A. U N A Z A W A

Faculty of Fisheries, University of Kagoshima, 4-50-20 Shimoarara.

Kagoshima 890-0088, Japan

33.1

Introduction

Nutritional studies on the spiny lobster (Panulirus sp. and Jasus sp.) are few, particularly on the larval stages, which are difficult to rear. The nutrition of American lobster Homarus americanus has been reviewed by several researchers (Kanazawa, 1980; Conklin, 1980; Conklin et al., 1983). In the present review, the nutrition of spiny lobster will be discussed and compared with that of the American lobster.

33.2

Protein and amino acids

Proteins are indispensable nutrients that are essential to the structure and overall function of all animals, including crustaceans. Researchers have reported optimum protein levels in diets for the American lobster, H . americanus, to be 60% (Castell & Budson, 1974), 53% (Gallagher et al., 1976) and 30.5% (Conklin et al., 1975; D’Abramo et al., 1981b). Differences in these values may be due to such factors as the size, age and stocking density of experimental lobsters, water temperature, dietary protein quality, level of non-protein energy and ration size. Ten amino acids (arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine) have been found to be essential for the American lobster (Gallagher, 1976). Protein and amino acid requirements of the spiny lobster are presumed to be similar to those of the American lobster. Galgani & Nagayama (1987) studied protein digestion in the spiny lobster Panulirus japonicus, and reported trypsin, collagenase, leucine aminopeptidase and carboxypeptidase A activities in the digestive gland. Rock crab (Cancer irroratus) protein was included in semipurified lobster diets and found to be nutritionally superior to casein and shrimp protein (Boghen et al., 1982; Castell et al., 1989a). An international co-operative effort to evaluate two possible Standard Reference Diets (SRD) for crustaceans was initiated at the 1984 World Mariculture Society meeting. One diet, BML 81 S (Table 33.1), was developed at the Bodega Marine Laboratory, University of California, Davis, USA; the other diet, HFX CRD 84 (Table 33.1), was developed at the Halifax Laboratory, Department of Fisheries and Oceans, Canada. Both of these diets were originally developed for H . americanus. The diets were compared with appropriate control 61 1

612 Spiny Lobsters: Fisheries and Culture Table 33.1 Formulation for the Halifax Crab Protein Reference Diet (HFX CRD 84) and the Bodega Bay Diet (BML 81 S) Ingredient Percentage composition Crab protein concentrate Casein (vitamin free) Egg white (spray dried) Wheat gluten Corn starch Dextrin Celufil (non-nutritive bulk) Cod liver oil Corn oil Soy lecithin Cholesterol Mineral mix (modified Bernhart-Tomarelli) Vitamin premix CRD Vitamin premix BML-2 Vitamin E (DL alpha-tocopherol) Vitamin A acetate (50 000 IU/g) Cholecalciferol (D3) (4 000 000 IU/g) Choline chloride (70%) IU or mg/kg of diet Thiamine, HCI Riboflavin Nico tinamide d-Biotin DL-Ca-Pantothenate Pyroidoxine, HCI Folk acid Menadione sodium bisulphite Cyanocobalamin (B12) Inositol Cholecalciferol (D3) (850 000 IU/g) Vitamin A acetate (500 000 IU/g) L-Ascorbic acid Butylated hydroxyanisole Butylated hydroxytoluene Para-amino benzoic acid Celufil

From Castell et al. (1989a).

HFX CRD 84

BML 81 S

40.0

5.0 15.0 5.0 17.8 6.0 3.0

1 .o 4.0 2.0 0.2

1.o

64 144 520 1.6

286 48 19.4 16 54 2540 340 51 000 1220 15.2 15.2 404 14 554

31.0 4.0 5.0 24.0

12.1 4.0 2.0 10.0 0.5 3.0 4.0 0.2 0.1 0.1

200 320 1040 40 600 120 200 40 7240

4840 40 1200 24 120

Nutrition and Food

6 13

diets by researchers in feeding trials with many different Crustacea including shrimp, prawn, lobster, crayfish and crab. Growth and survival data of feeding trials with Pandalus danae, Penaeus monodon, P. stylirostris, P. vannamei, P. brasiliensis, P. setiferus, P. aztecus, Macrobrachium rosenbergii, H . americanus, Cherax tenuimanus and Cancer rnagister suggest that either BML 81 or HFX CRD 84 would be an acceptable SRD for these species (Castell et al., 1989b; Reed & D’Abramo, 1989; Morrissy, 1989; Bordner, 1989). However, the survival of second-moult post-larval spiny lobster Panulirus argus was greater for animals fed live adult Artemia (93.3%) than for lobsters fed HFX CRD 84 (26.7%) or BML 81 S (0%) (Fig. 33.1) (Lellis, 1992). Lobsters offered the casein-based BML 81 S did not consume the food. These results suggest that the feeding behaviour and nutrition for the early post-larval period of spiny lobster may be different from that of the American lobster.

33.3

Essential fatty acids

The absence of de novo synthesis of linoleic (18:2n-6), linolenic (18:3n-3), eicosapentaenoic (20:5n-3), and docosahexaenoic (22:6n-3) acids from [14C]acetate has been demonstrated in the European lobster, Homarus gammarus (Zandee, 1967) and the spiny lobster, P. japonicus (Kanazawa, unpubl. data). These data suggest that lobsters may require some of these fatty acids as essential dietary nutrients. Castell & Covey (1976) have found that cod liver oil [high in n-3 highly unsaturated fatty acids (HUFA)] was superior to corn oil (high in 18:2n-6) for growth of adult lobsters and the optimum concentration of cod liver oil in diets was 5% w/w. Growth of juvenile lobsters was enhanced when lobsters were fed diets rich in n-3 HUFA (D’Abramo et al., 1980). loo*

--s

80

-

60

-

40

-

20

-

A

-

-

Artemia 0

0

.-> 2 a

v)

0

0

HFX CRD 84

10

20

30

I

I

I

I

40

50

60

70

Number of days

Fig. 33.1 Effect of diets on survival of second-stage post-larval spiny lobsters, Panulirus argus. From Lellis (1992).

614 Spiny Lobsters: Fisheries and Culture 33.4

Phospholipids

Kanazawa et al. (1979) showed that the addition of phospholipids to artificial diets, especially the lecithin fraction from the short-necked clam Tapes philippinarum, increased the growth rate of Penaeus japonicus. Conklin et al. (1980) showed that the survival rate of juvenile American lobsters was significantly improved by addition of 7.5% soybean lecithin to purified diets. A deficiency of lecithin in lobster diets resulted in high mortality rates caused by the lobster’s inability to complete ecdysis. D’Abramo et al. (198 la) then discovered that the nutritionally important component of soybean lecithin was phosphatidylcholine. One important role that phospholipids apparently play in crustacean nutrition is in the transport of fat-soluble nutrients in the haemolymph. D’Abramo et al. (1982, 1985) showed that a dietary phospholipid deficiency in lobsters reduced cholesterol transport in the haemolymph, and that the absence of dietary phosphatidylcholine in a purified diet fed to juvenile lobsters was associated with a significant reduction in serum cholesterol titres throughout most of the moult cycle. Kean et al. (1985a) fed juvenile American lobsters with crab proteinbased purified diets containing three concentrations of soybean lecithin at 0, 3 and 6% w/w; however, no significant effect of dietary lecithin on lobster growth or survival was observed. Baum et al. (1990) reported that juvenile lobsters fed on diets supplemented with lecithin had significantly higher levels of serum cholesterol than lobsters fed diets without supplemental lecithin, regardless of the source of protein (casein or crab protein) included in the diet.

33.5

Sterols

Mammals can synthesize cholesterol from low molecular weight precursors such as acetate and mevalonate. However, a unique aspect of the lipid nutrition of crustaceans is that they require dietary sources of sterol for growth and survival because of the absence of de n o w sterol-synthesizingability. The lack of cholesterol biosynthesis from ‘‘C-labelled precursors has also been noted in the lobsters P . japonicus (Teshima & Kanazawa, 1971) and H . gammarus (Zandee, 1967). Castell et al. (1975) reported that the dietary concentration of cholesterol required by juvenile American lobsters was 0.5%, while D’Abramo et al. (1984) found that a dietary cholesterol concentration as low as 0.12% was satisfactory for normal growth and survival of juvenile lobsters fed on purified diets. The optimum levels of cholesterol in diets for a variety of crustaceans range from 0.2 to 2.0%. Total replacement of cholesterol with a mixture of phytosterols composed mainly of P-sitosterol, did not yield satisfactory growth and survival of American lobsters (D’Abramo et al., 1984). In higher animals, cholesterol is an important precursor of bile salts, steroid hormones and vitamin D. It has been demonstrated in the spiny lobster, P . japonicus, that exogenous cholesterol is converted to sex hormones such as progesterone,

Nutrition and Food

6 15

Table 33.2 Metabolites from ['4C]cholesterolidentified in the hepatopancreas, ovaries and blood of Panulirus japonicus

Steroid hormones

Hepatopancreas

Progesterone 17-Hydroxyprogesterone Androstenedione Testosterone Deoxycorticosterone Corticosterone

+ + + + + +

Ovaries

Blood

From Kanazawa & Teshima (1971). 17-hydroxyprogesterone, androstenedione, and testosterone (Table 33.2) (Kanazawa & Teshima, 1971) and moulting hormones such as ecdysterone (Fig. 33.2) (Kanazawa & Kimura, 1972). The fate of ['4C]cholesterol was studied in the tissues of P . japonicus, kept for 2, 10 and 20 days after injection (Teshima, 1972). Throughout the experimental period, free sterols were predominant in all tissues examined except for the gonads. In the gonads of lobsters kept for 20 days after injection of ['4C]cholesterol, the percentage of polar compounds (63.5%) was higher than that of free sterols (24.7%).

33.6

Minerals

Lobsters, like other marine crustaceans, absorb minerals from the seawater; however, since minerals are lost during each moulting, supplementation of feeds with minerals is usually practised. Adult lobsters in the wild apparently consume diets with high calcium contents prior to moulting (Weiss, 1970). According to Conklin et al. (1975), high-calcium diets did not influence the growth and survival of American lobsters, but had an enhancing effect on mineralization of the exoskeleton. HO ?H

Cholesterol

20-Hydroxyecdysone

Fig. 33.2 Biosynthesis of moulting hormone from ['4C]cholesterol in spiny lobster Panulirus japonicus. From Kanazawa and Kimura (1972).

616 Spiny Lobsters: Fisheries and Culture Gallagher et al. (1978, 1982) suggested that a dietary calcium/phosphorous ratio of approximately 1: 1 was optimal for juvenile and adult lobsters. The nutritionally induced ‘moult death’ of juvenile lobsters, H . americanus had been found to be eliminated by the addition of soybean lecithin to casein-based diets; however, the addition of lecithin was unnecessary if casein was replaced with crab protein. Further purification of the crab protein to reduce ash content resulted in the reappearance of ‘moult death’ (Conklin et al., 1991). Castell et al. (1991) studied the effect of B vitamins or B vitamins plus manganese deficiency on ‘moult death’ of juvenile lobsters. They found that a deficiency of B vitamins resulted in greater ‘moult death’ of lobsters fed on casein/albumin plus lecithin diets than in lobsters fed on crab protein-based diets. Lobsters fed on crab protein diets deficient in B vitamins and manganese suffered high mortality by week 12 of the feeding trial. According to Baum et al. (1991), supplementation of one of the standard crustacean reference diets, BML 81 S, with twice the normal amount of calcium was effective in preventing ‘moult death’ of juvenile lobsters, however, increasing calcium content of casein-based diets without lecithin did not prevent ‘moult death’. Increase in lobster wet weight over the 90 day experimental period was not affected by dietary calcium concentration or a lack of minerals. The role of nutrition on ecdysis of the lobster appears to be complex and is affected by a number of nutritional factors, such as fatty acid, phospholipid, protein and mineral composition. Recently, Davis & Gatlin (1 996) summarized the dietary mineral requirements of marine crustaceans. Seven minerals of calcium, copper, phosphorus, potassium, magnesium, selenium and zinc have been recommended for lobster.

33.7

Vitamins

It has been concluded for the penaeid, P . japonicus, that B vitamins (thiamine, riboflavin, nicotinic acid, pyridoxine, pantothenate, biotin, folic acid, vitamin B12)as well as choline, inositol, vitamin C and fat-soluble vitamins (vitamin E, vitamin D and P-carotene) are essential in the diet (Kanazawa, 1985, 1989). It is assumed that lobsters, like other animals, will require dietary vitamins; however, the lobster’s response to deletion of individual vitamins from a purified diet has not been demonstrated. A significant positive growth effect in juvenile lobsters has been suggested when a 4% vitamin mixture was added to a purified diet (Conklin et al., 1980). Recently, the effect of vitamin D supplemented pelleted feed on weight gain and shell hardness of the lobster H . americanus was described (Donahue et ul., 1996). Shrimp fed diets deficient in vitamin C developed ‘black death’ syndrome, which is characterized by blackened lesions in the subcuticular tissues of the body surface, the walls of the oesophagus, stomach and hindgut, and the gills and gill cavity (Lightner et al., 1977). It has been reported that the spiny lobster P . japonicus possesses no ability to synthesize vitamin C from [‘4C]glucose (Kanazawa, et al., 1972). In contrast, the American lobster, H . americanus, was able to synthesize vitamin C and

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no requirement for exogenous vitamin C was demonstrated (Desjardins et al., 1985; Kean et al., 1985b). The vitamin C content of diets is usually high to compensate for losses due to processing, storage and leaching. It is estimated that the amount of vitamin C actually consumed by crustaceans is about one-tenth of that added to the diets. Recently, stable vitamin C compounds such as magnesium L-ascorbyl-2phosphate, L-ascorbyl-2-sulphate, L-ascorbyl-2-polyphosphate and coated ascorbic acid have been developed and have shown promising results in some studies.

33.8

Attractants

Sensitiveness of the spiny lobster to feeding stimulants have been demonstrated in electrophysiological investigations. Adenosine 5’-triphosphate (ATP), taurine, other amino acids, amines, organic acids, abalone muscle, crab muscle and shrimp muscle all stimulate feeding in P . argus (Ache et al., 1976; Fuzessery et al., 1978) and P . interruptus (Zimmer-Faust & Case, 1982, 1983; Zimmer-Faust et al., 1984a, b, 1986, 1993).

33.9

Carotenoids

@-Carotene,echinenone, canthaxanthin and astaxanthin have been reported in the carapaces of the spiny lobster P . japonicus (Matsuno et al., 1973; Katayama et al., 1973). Pigmentation of cultured lobsters is dependent on the presence of dietary carotenoids. Inclusion of carotenoids in a purified diet results in the accumulation of exoskeleton pigments (D’Abramo et al., 1983).

33.10

Larval food

Larval rearing of the spiny lobster has been generally tried using Artemia salina, Segitta sp., Mytilus edulis and fish fry as food for the phyllosoma and puerulus larval stages. Some researchers had succeeded in rearing the spiny lobster through all larval stages. Culture of larvae of the spiny lobster Jasus lalandii was first accomplished by feeding larvae on a combination of Artemia and chopped Mytilus from egg to puerulus stage (Kittaka, 1988). In addition, hybrid larvae (Jasus novaehollandiae x Jasus edwardsii) were cultured on a diet of Artemia and Mytilus edulis from the egg to puerulus stage (Kittaka et al., 1988). Larvae of P . japonicus were successfully reared from the phyllosoma stage to the puerulus stage when fed on Artemia nauplii, adult Artemia grown on marine diatom and chopped gonads of the mussel M . edulis (Kittaka & Kimura 1989; Yamakawa et al., 1989). Sekine et al. (1990, 1991, 1992) showed that the experimental diet of Artemia enriched with Phaeodactylum sp. and small pieces of Mytilus ovary was best for moulting, growth

6 18 Spiny Lobsters: Fisheries and Culture

and survival of phyllosoma larvae. Recently, Rodriguez Souza et al. (1996) have detected the differences in the nutritional value of diets of P . japonicus phyllosoma larvae. The growth of phyllosoma fed diets of M . edulis ovary or combination of M . edulis ovary plus Artemia have shown better results than M . edulis testis plus Artemia. Tong et al. (1997) determined the optimum requirement of Artemia salina for the growth and survival of phyllosoma larvae of J. edwardsii. Kittaka & Abrunhosa (1997) have accomplished the complete development of spiny lobster phyllosoma. First instars of Palinurus elephas exhibited vigorous predation upon the larvae of Japanese sandfish Actoscopus japonicus. Better results were obtained for first instars cultured in water inoculated with Chaetoceros sp. and fed enriched Artemia nauplii. Kittaka (1997a) has developed a method to culture phyllosoma larvae of spiny lobsters. Newly hatched larvae of sailfin sandfish (Actoscopus japonicus) were an excellent food for phyllosomas of Jasus verreauxi. Palinurus elephas phyllosoma raised in coculture with diatoms and fed mussel gonad and A . japonicus larvae metamorphosed into a puerulus. Kittaka (1997b) has achieved the ecosystem culture method for complete development of phyllosomas of spiny lobsters P . japonicus, P . elephas, J. lalandii, J . edwardsii and J . verreauxi. The larval culture container was connected to a microalga Nannochloropsis spp. culture tank and water recirculated between the two. For the early phyllosomas, food consisted of Artemia nauplii in combination with pieces of M . edulis gonad. Mussel gonad was used exclusively after the second and third instars. Non-feeding during the puerulus stage has been proven by culture experiments of J. verreauxi and J . lalandii (Kittaka, 1988, 1995). However, Wei & Yang (1996) reported on experiments with food for the puerulus larvae Panulirus stimpsoni. A better result was obtained when A. salina and the flesh of Mollusca were fed alternately. The growth of post-pueruli of J. edwardsii fed mussel diets was measured by James & Tong (1997). Post-pueruli fed frozen blue mussel (Mytilus galloprovincialis) grew significantly more than those fed frozen greenlip mussel (Perna canaliculus).

33.11

Juvenile food

Juveniles of the Californian spiny lobster P . interruptus were successfully cultured on a minced diet of abalone, mussels, squid, fish flesh, crabs, etc. (Serfling & Ford, 1975). Early juveniles of the western rock lobster, P . cygnus, were successfully reared on a diet of mussels, abalone and occasional pieces of various species of teleost fish (Phillips, et al., 1977). Compound diets for juveniles of the lobster H . gammarus were tested by Moreau et al. (1985). Feeding trials were also conducted to evaluate several commercial diets, including Kyowa Fry Feeds (Kyowa Hakko Kogyo Co. Ltd. Japan), as first foods for the post-larval stages of the spiny lobster P . argus. Spiny lobsters required live Artemia to complete the first, and possibly second post-larval moults, and

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compound feeds could satisfactorily replace live food as the sole source of nutrition (W.A. Lellis, Harbor Branch Oceanographic Institute, Florida, USA, pers. comm.). Culture of the puerulus and juvenile stages of P . argus was carried out to determine the effects of various feeds on growth and survival. A diet of live Artemia alone resulted in significantly higher lobster growth rates than a combination of Artemia and pelleted feed, but survival was not significantly different between treatments (Pardee & Foster, 1992).

33.12

Growout food

In Japan, the spiny lobster, P . japonicus has frequently been kept in cages and cultured from juvenile to a commercial size on a diet of fresh fish and gastropods. However, the feeding of fish, such as mackerel and sardine, often resulted in a decline in weight gain, discoloration and poor-quality lobster meat. Matsuoka et af. (1978) tested artificial, formulated diets for the spiny lobster P . japonicus. The results of an 8-month feeding trial indicated good growth of lobsters fed on commercial pelleted diets originally developed for red sea bream as well as the Oregon moist pellet. Matsuoka et al. (1979) have cultured the same spiny lobsters on pellets (moisture content 12.2%) for over 2 years, and reported normal moulting, growth and ovarian maturation of lobsters, but no adequate growth and ovarian maturation for those fed fish. There is a scarcity of research on, and recommendations for, suitable feeds for caged spiny lobsters. However, it appears that spiny lobsters accept and respond well to artificial compounded diets, emphasizing the importance of formulating and designing diets specific to the requirements and feeding behaviour of this species. The important characteristic of the feed is to remain stable in water for several hours until consumed. Recently, the growth of small juvenile P . ornatus to a marketable size was accelerated by unilateral ablation treatment (Juinio Menex 8c Ruinata, 1996).

33.13

Conclusions

Jasus lalandii and hybrid J. novaehollandiae x J . edwardsii have been reared successfully through all larval stages, feeding on Artemia and other natural foods. Early juveniles of P . cygnus were likewise cultured successfully on natural foods. Panulirus argus and P . interruptus were shown to be sensitive to attractants to stimulate feeding. However, P. argus demonstrated preference for Artemia in the early post-larval stages over SRD HFX CRD 84 and BML 81 S. No report is available regarding the nutritional requirements and feed development for these species.

620 Spiny Lobsters: Fisheries and Culture Among the panulirids, ‘Ise-ebi’ or P . japonicus received more research attention covering carapace pigmentation, nutrient metabolism, digestive physiology and nutrition. The fate of [14C]cholesterolin tissues after 20 days of injection and the conversion of cholesterol to sex and moulting hormones have been identified and confirmed. The lack of cholesterol biosynthesis from ‘‘C-labelled precursors and the absence of de novo synthesis of linoleic, linolenic, eicosapentaenoic and docosahexaenoic fatty acids demonstrate the necessity of an exogenous source of these dietary nutrients. Although protein digestive enzymes in the digestive gland have been studied, dietary protein and amino acid requirements have not been investigated. Phospholipid, mineral and carotenoid requirements remain unknown. Ascorbic acid is an essential vitamin for this species, whereas other vitamins have not been determined. Attractants, such as peptides and extracts of squid, mussel and clam, which have been shown to stimulate the feeding response of penaeid shrimps (Kanazawa, 1985) need to be investigated and defined for spiny lobsters. A wide area has not been explored; this is partly due to the still incomplete larval rearing success of P . japonicus. Natural food remains the sole food for the larval stages. There are strong implications that in order to formulate artificial first feed for the larvae, natural prey organisms ingested at this early stage of the development have to be identified. Enough evidence suggests that juvenile P . argus respond well to a combination of natural and artificial food and the P . japonicus growout stages can be reared on compounded diets. Since knowledge on nutritional requirements is still rudimentary, a better approach would be to look closely at the nutrient composition of wild spiny lobsters at different stages of development and thereafter, develop diets that simulate this nutrient pattern. Although gonadal maturation studies have not been conducted, this area appears to be promising since evidence shows that P . ,japonicus can mature in captivity fed on artificial diets. While the information presented here makes a significant contribution to the knowledge of spiny lobster nutrition, many questions remain unanswered. These gaps in the information certainly need to be investigated further in the future.

References Ache, B.W., Fuzessery, Z.M. 8c Carr, W.E.S. (1976) Antennular chemosensitivity in the spiny lobster, Panulirus argus: comparative tests of high and low molecular weight stimulants. Biol. BUN.,151, 273-82. Baum, N.A., Conklin, D.E., Castell, J.D. & Boston, L.D. (1991) Nutritionally induced molt death syndrome in aquatic crustaceans: 111. The effect of varying levels of calcium in the reference diet, BML 81 S for juvenile (Homarus americanus). Crust. Nutr. Newslett., 7 , 115-18. Baum, N.A., Conklin, D.E. & Chang, E.S. (1990) Effect of dietary lecithin in combination with casein or crab protein on cholesterol uptake and transport in the lobster Homarus americanus. J. World Aquacult. Soc., 21, 271-87. Boghen, A.D., Castell, J.D. & Conklin, D.E. (1982) In search of a reference protein to replace ‘vitamin-free casein’ in lobster nutrition studies. Can. J. Zool., 60, 2033-8.

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Bordner, C.E. (1989) A standard reference diet for crustacean nutrition research. V. Growth and survival of juvenile dungeness crabs Cancer magister. J. World Aquacult. SOC.,20, 118-21. Castell, J.D. & Budson, S.D. (1974) Lobster nutrition: the effect on Homarus americanus of dietary protein levels. J. Fish. Res. Bd Can., 31, 1363-70. Castell, J.D. & Covey, J.F. (1976) Dietary lipid requirements of adult lobster, Homarus americanus (M.E.). J . Nutr., 106, 1159-65. Castell, J.D., Boston, L.D., Conklin, D.E. & Baum, N. (1991) Nutritionally induced molt death syndrome in aquatic crustaceans: 11. The effect of B vitamin and manganese deficiencies in lobster (Homarus americanus). Crust. Nutr. Newslett., 7 , 108-14. Castell, J.D., Kean, J.C., D’Abramo, L.R. & Conklin, D.E. (1989a) A standard reference diet for crustacean nutrition research. I. Evaluation of two formulations. J. World Aquacult. Soc., 20, 93-9. Castell, J.D., Kean, J.C., McCann, D.G.C., Boghen, A.D., Conklin, D.E. & D’Abramo, L.R. (1989b) A standard reference diet for crustacean nutrition research. 11. Selection of a purification procedure for production of the rock crab Cancer irroratus protein ingredient. J . World Aquacult. Soc., 20, 1OM. Castell, J.D., Mason, E.G. & Covey, J.F. (1975) Cholesterol requirements of juvenile American lobster (Homarus americanus). J. Fish. Res. Bd Can., 32, 1431-5. Conklin, D.E. (1980) Nutrition. In The Biology and Management of Lobsters, Vol. 1 (Ed.by J.S. Cobb & B.F. Phillips), pp. 277-300. Academic Press, New York, USA. Conklin, D.E., Baum, N.A., Castell, J.D., Boston, L.D. & Li, F. (1991) Nutritionally induced molt death syndrome in aquatic crustacean: I. Introduction to the problem. Crust. Nutr. Newslett., 7 , 102-7. Conklin, D.E., D’Abramo, L.R., Bordner, C.E., & Baum, N.A. (1980) A successful purified diet for the culture of juvenile lobsters: the effect of lecithin. Aquaculture 21: 243-9. Conklin, D.E., D’Abramo, L.R. & Norman-Boudreau, K. (1983) Lobster nutrition. In CRC Handbook of Mariculture, Vol. 1, Crustacean aquaculture (Ed. by J.P. McVey), pp. 413-23. CRC Press, Boca Raton, FL, USA. Conklin, D.E., Devers, K. & Shleser, R.A. (1975) Initial development of artificial diets for the lobster Homarus americanus. Proc. World Maricult. SOC.,6, 23743. D’Abramo, L.R., Baum, N.A., Bordner, C.E. & Conklin, D.E. (1983) Carotenoids as a source of pigmentation in juvenile lobsters fed a purified diet. Can. J. Fish. Aquat. Sci., 40, 699-704. D’Abramo, L.R., Baum, N.A., Bordner, C.E., Conklin, D.E. & Chang, E.S. (1985) Diet-dependent cholesterol transport in the American lobster. J. Exp. Mar. Biol. Ecol., 87, 83-96. D’Abramo, L.R., Bordner, C.E. & Conklin, D.E. (1982) Relationship between dietary phosphatidylcholine and serum cholesterol in the lobster Homarus sp. Mar. Biol., 67, 231-5. D’Abramo, L.R., Bordner, C.E., Conklin, D.E. & Baum, N.A. (1981a) Essentiality of dietary phosphatidylcholine for the survival of juvenile lobsters. J. Nutr., 111, 425-31. D’Abramo, L.R., Bordner, C.E., Conklin, D.E. & Baum, N.A. (1984) Sterol requirement ofjuvenile lobsters, Homarus sp. Aquaculture, 42, 13-25. D’Abramo, L.R., Bordner, C.E., Daggett, G.R., Conklin, D.E. & Baum, N.A. (1980) Relationships among dietary lipids, tissue lipids, and growth in juvenile lobsters. Proc. World Maricult. Soc., 11, 33545. D’Abramo, L.R., Conklin, D.E., Bordner, C.E., Baum, N.A. & Norman-Boudreau, K.A. (1981b) Successful artificial diets for the culture of juvenile lobsters. Proc. World Maricult. Soc., 12, 325-32. Davis, D.A. & Gatlin, D.M., 111 (1996) Dietary mineral requirements of fish and marine crustaceans. Rev. Fish. Sci., 4, 75-99. Desjardins, L.M., Castell, J.D. & Kean, J.C. (1985) Synthesis of dehydroascorbic acid by subadult lobsters (Homarus americanus). Can. J . Fish. Aquat. Sci., 42, 370-3.

622 Spiny Lobsters: Fisheries and Culture Donahue, D., Bayer, R., Work, T. & Riley, J. (1996) The effect of diet on weight gain, shell hardness, and flavour of new shell lobsters. J. Shellfirh Res., 15, 4934. Fuzessery, Z.M., Carr, W.E.S. & Ache, B.W. (1978) Antennular chemosensitivity in the spiny lobster, Panulirus argus: studies of taurine sensitive receptors. Biol. Bull., 154, 226-40. Galgani, F. & Nagayama, F. (1987) Digestive proteinases in the Japanese spiny lobster Panulirus japonicus . Comp. Biochem . Physiol., 87B,889-9 3. Gallagher, M.L. (1976) The nutritional requirements of juvenile lobster (Homarus americanus). Ph.D. thesis, University of California, Davis, USA. Gallagher, M.L., Bayer, R.C., Rittenburg, J.H. & Leavitt, D.F. (1982) Studies on the mineral requirements of the adult American lobster. Prog. Fish-Cult., 44,210-12. Gallagher, M.L., Brown, W.D., Conklin, D.E. & Sifri, M. (1978) The effects of diet with varying calciumlphosphorous ratios when fed to juvenile lobsters. Comp. Biochem. Physiol., 60A, 467-7 1. Gallagher, M.L., Conklin, D.E. & Brown, W.D. (1976) The effects of pelleted protein diets on growth, moulting and survival of juvenile lobsters. Proc. World Maricult. SOC.,7,363-78. James, P.J. & Tong, L.J. (1997) Differences in growth and moult frequency among post-pueruli of Jasus edwardsii fed fresh, aged or frozen mussels. Mar. Freshwat. Res., 48, 9314. Juinio Menez, M.A. & Ruinata, J. (1996) Survival, growth and food conversion efficiency of Panulirus ornatus following eyestalk ablation. Aquaculture, 146,225-35. Kanazana, A. (1980) Nutritional requirements of lobster, shrimp, and prawn. Mar. Sci., 12, 864-71 (in Japanese). Kanazawa, A. (1985) Nutrition of penaeid prawns and shrimps. Proc. 1st Int. Conf. on Culture of Penaeid PrawnslShrimps, SEAFDEC Aquaculture Dept, Philippines, pp. 123-30. Kanazawa, A. (1 989) Microparticulate feeds for penaeid larvae. Advances in Tropical Aquaculture, AQUACOP IFREMER, Actes de Colloque 9, Tahiti, pp. 395404. Kanazawa, A. & Kimura, S. (1972) Molting hormones in crustaceans 11. Conversion of ch~lesterol-'~C to ecdysterone in the spiny lobster. Abst. Annu. Meet. Nippon Suisan Gakkai, p. 239. Kanazawa, A. & Teshima, S. (1971) In vivo conversion of cholesterol to steroid hormones in the spiny lobster, Panulirus japonicus. Nippon Suisan Gakkaishi, 37,891-8. Kanazawa, A., Tanaka, N., Kashiwada, K., Castela, M. & Guary, J.C. (1972) Nutritional requirements of prawn-X. Synthesis and requirement of ascorbic acid. Abst. Annu. Meet. Nippon Suisan Gakkai, p. 175. Kanazawa, A., Teshima, S., Tokiwa, S., Endo, M. & Abdel-Razek, F.A. (1979) Effects of shortnecked clam phospholipids on the growth of prawns. Nippon Suisan Gakkaishi, 45, 961-5. Katayama, T., Shimaya, M., Sameshima, M. Br Chichester, C.O. (1973) The biosynthesis of astaxanthin-XI. The caroteniids in the lobster, Panulirus japonicus. Nippon Suisan Gakkaishi, 39, 215-20. Kean, J.C., Castell, J.D., Bodhen, A.G., DAbramo, L.R. & Conklin, D.E. (1985a) A re-evaluation of the lecithin and cholesterol requirements of juvenile lobster (Homarus americanus) using crab protein-based diets. Aquaculture, 47, 143-9. Kean, J.C., Castell, J.D. & Trider, D.J. (1985b) Juvenile lobster (Homarus americanus) do not require dietary ascorbic acid. Can. J. Fish. Aquat. Sci., 42,368-70. Kittaka, J. (1988) Culture of the palinurid Jaws Zalandii from egg stages to puerulus. Nippon Suisan Gakkaishi, 54, 87-93. Kittaka, J. (1995) Non-feeding stage of some crustacean larvae and its implication in aquaculture. Abstracts of the Fifth International Working Group on Crustacean Nutrition Symposium. April 22-24, 199S, Kagoshima, Japan, p. 49. Kittaka, J. (1997a) Culture of larval spiny lobsters: a review of work done in northern Japan. Mar. Freshwat. Res., 48,923-30.

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Kittaka, J. (1997b) Application of ecosystem culture method for complete development of phyllosomas of spiny lobster. Aquaculture, 155, 1 4 . Kittaka, J. & Abrunhosa, F.A. (1997) Characteristics of palinurids (Decapoda, Crustacea) in larval culture. Hydrobiologia, 358, 305-1 1. Kittaka, J., Iwai, M. & Yoshimura, M. (1988) Culture of a hybrid of spiny lobster genus Jasus from egg stage to puerulus. Nippon Suisan Gakkaishi, 54, 413-19. Kittaka, J. & Kimura, K. (1989) Culture of the Japanese spiny lobster Panulirusjaponicus from egg to juvenile stage. Nippon Suisan Gakkaishi, 55, 963-70. Lellis, W.A. (1992) A standard reference diet for crustacean nutrition research VI. Response of postlarval stages of the Caribbean king crab Mithrax spinosissimus and the spiny lobster Panulirus argus. J. World Aquacult. Soc., 23, 1-7. Lightner, D.V., Colvin, L.B., Brand, C. & Donald, D.A. (1977) ‘Black Death’, a disease syndrome of penaeid shrimp related to a dietary deficiency of ascorbic acid. Proc. World Maricult. Soc., 8, 61 1-24. Matsuno, T., Kusumoto, T., Watanabe, T. & Ishihara, Y. (1973) Carotenoid pigments of spiny lobster. Nippon Suisan Gakkaishi, 39, 43-50. Matsuoka, T., Harada, Y & Hasegawa, M. (1978) Grow-out test for spiny lobster 11. (in Japanese) Ann. Report of Shizuoka Fisheries Research Station, pp. 16671. Matsuoka, T., Hasegawa, M., Tsuchiya, S. & Hashimoto, T. (1979) Grow-out test for spiny lobster 111. Annual Report of Shizuoka Fisheries Research Station, pp. 22630 (in Japanese). Moreau, G., Henocque, Y., Van Wormhoudt, A., Martin, B.J. & Ceccaldi, H.J. (1985) Adaptation bioshimiques a des aliments composes et croissance chez le homard juvenile, Homarus gammarus L.: resultats preliminaires. Aquaculture, 48, 3 13-29. Morrissy, N.M. (1989) A standard reference for diet for crustacean nutrition research. IV. Growth of freshwater crayfish Cherax tenuimanus. J. World Aquacult. SOC.,20, 114-17. Pardee, M.G. & Foster, S.M. (1992) Culture of puerulus through juvenile spiny lobster (Panulirus argus): evaluation of live and supplemental feeds on growth and survivorship. Abstracts of World Aquaculture 92, Orlando, Florida, p. 180. Phillips, B.F., Campbell, N.A. & Rea, W.A. (1977) Laboratory growth of early juveniles of the western rock lobster Panulirus longipes cygnus. Mar. Biol., 39, 3 1-9. Reed, L. & D’Abramo, L.R. (1989) A standard reference diet for crustacean nutrition research. 111. Effects on weight gain and amino acid composition of whole body and tail muscle of juvenile prawns Macrobrachium rosenbergii. J. World Aquacult. Soc., 20, 107-1 3. Rodriguez Sowa, J.C., Sekine, S., Suzuki, S., Shima, Y., Struessmann, C.A. & Takashima, F. (1996) Usefulness of histological criteria for assessing the adequacy of diets for Panulirus japonicus phyllosoma larvae. Aquacult. Nutr., 2, 133-40. Sekine, S., Shima, Y, Fushimi, H. & Nonaka, M. (1991) Culture of phyllosoma Panulirusjaponicus 11. Live food for the middle phyllosoma stage. Abst. Annu. Meet. Nippon Suisan Gakkai, p. 243 (in Japanese). Sekine, S., Shima, Y., Fushimi, H. & Nonaka, M. (1992) Culture of phyllosoma Panulirusjaponicus V. From phyllosoma stage to juvenile. Abst. Annu. Meet. Nippon Suisan Gakkai, p. 197 (in Japanese). Sekine, S . , Watanabe, K., Kamoshida, M. Fushimi, H. & Nonaka, M. (1990) Culture of phyllosoma Panulirus japonicus : larval food. Abst. Annu. Meet. Nippon Suisan Gakkai, p. 186 (in Japanese). Serfling, S.A. & Ford, R.F. (1975) Laboratory culture of the California spiny lobster Panulirus interruptus (Randall) at elevated temperatures. Aquaculture, 6, 377-87. Teshima, S. (1972) Studies on the sterol metabolism in marine crustaceans. Mem. Fuc. Fish., Kagoshima Univ. 21: 69-147.

624 Spiny Lobsters: Fisheries and Culture Teshima, S. & Kanazawa, A. (1971) Biosynthesis of sterols in the lobster, Panulirus japonicus, the prawn, Penaeus japonicus, and the crab, Portunus trituberculatus. Comp. Biochem. Physiol., 38B, 597402. Tong, L.J., Moss, G.A., Paewai, M.M. & Pickering, T.D. (1997) Effect of brine-shrimp numbers on growth and survival of early-stage phyllosoma larvae of the rock lobster Jasus edwardsii. Mar. Freshwat. Res., 48, 935-40. Wei, S. & Yang, X. (1996) Experiments of the food and the salinity for the puerulus larvae of Panulirus stimpsoni (Holthuis). Mar. Sci. Bull. Haiyang Tongbao, 15, 92-6. Weiss, H.M. (1970) The diet and feeding behavior of the lobster, Homarus americanus, in Long Island Sound. Ph.D. thesis, University of Connecticut, Storrs, USA. Yamakawa, T., Nishimura, M., Matsuda, H. Tsujigado, A. & Kamiya, N. (1989) Complete larval rearing of the Japanese spiny lobster Panulirus japonicus. Nippon Suisan Gakkaishi, 55, 745. Zandee, D.I. (1967) Absence of cholesterol synthesis as contrasted with the presence of fatty acid synthesis in some arthropods. Comp. Biochem. Physiol., 20, 81 1-22. Zimmer-Faust, R.K. (1986) Are feeding responses by Crustacea tuned to the relative energy and nutrient qualities of odor’? Chem. Senses, 11, 686. Zimmer-Faust, R.K. (1993) ATP: A potent prey attractant evoking carnivory. Limnol. Oceanogr., 38, 1271-5. Zimmer-Faust, R.K. & Case, J.F. (1982) Odors influencing foraging behavior of the California spiny lobster, Panulirus interruptus, and other decapod Crustacea. Mar. Behav. Physiol., 9, 35-58. Zimrner-Faust, R.K. & Case, J.F. (1983) A proposed dual role of odor in foraging by the California spiny lobster, Panulirus interruptus (Randall). Biol. Bull., 164, 341-53. Zimmer-Faust, R.K., Michel, W.C., Tyre, J.E. & Case, J.F. (1984a) Chemical induction of feeding in California spiny lobster, Panulirus interruptus (Randall): response to molecular weight fraction of abalone. J . Chem. Ecol., 10, 957-71. Zimmer-Faust, R.K., Tyre, J.E., Michel, W.C. & Case, J.F. (1984b) Chemical mediation of appetitive feeding in a marine decapod crustacean: The importance of suppression and synergism. Biol. Bull., 167, 339-53.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 34

Colour and Taste s. KONOSU

1-26-6 Kugahara, Ota-ku, Tokyo 146-008.5.Japan

K. YAMAGUCHI

34.1

1608, Hikawa, Okutama, Tokyo 198-0212, Japan

Introduction

External appearance, such as shape and colour, and sensory attributes, such as taste and smell, are important factors affecting the price and acceptance of foods. In this chapter the exoskeletal pigments of the spiny lobster and the taste-producing components of its tail muscle are briefly explained. Black discoloration in the integument and its prevention are also discussed.

34.2

Colour

The colour of the carapace and tail varies depending upon the presence of dietary carotenoids in the lobster’s habitat, with well-pigmented lobsters being generally more commercially acceptable because the desirable red coloration can be expected when they are cooked. Black discoloration is often observed in the integument of spiny lobsters during storage, freezing and thawing.

34.2.1

Colour of exoskeleton

The colour of the exoskeleton of live Japanese spiny lobster varies among individuals, from reddish purple to dark red. Carotenoids and carotenoproteins are responsible for natural pigmentation in crustaceans. Matsuno et al. (1973) investigated the carotenoids in the carapace and exuvia of the Japanese spiny lobster Punulirus juponicus, and found nine carotenoids present in free and esterified forms in the carapace and four carotenoids in free form in the exuvia (Table 34.1). The major carotenoids of the carapace are astaxanthin and 4-ketozeaxanthin, accounting for 45% and 30% of the total pigment respectively, and the dominant ones in the exuvia are astaxanthin (67%) and phoenicoxanthin (21 YO).The reddish tone of the exoskeleton is ascribed to such carotenoids as astaxanthin, 4-ketozeaxanthin, phoenicoxanthin, canthaxanthin and echinenone, all of which are red pigments (Thommen, 1971). Part of the free astaxanthin probably exists as a protein complex, carotenoprotein, which is characterized by a very large bathochromic shift in the light absorption spectrum, giving rise to purple and blue colours, in contrast to the 625

626 Spiny Lobsters: Fisheries and Culture Table 34.1 Percentage composition of carotenoids in the carapace and exuvia of Japanese spiny lobster Panulirus japonicus

Carotenoid @-Carotene Echinenone Canthaxanthin Phoenicoxanthin Lutein diester Zeaxanthin diester Zeaxanthin Cynthiaxanthin diester Cynthiaxanthin 4-Ketozeaxanthin diester 4-Ketozeaxanthin monoester 4-Ketozeaxanthin Astaxanthin diester Astaxanthin monoester Astaxanthin

Carapace

Exuvia

1.8 2.0 5.0 3.5 0.7

-

4.6 21.0 -

1.2 1.5 2.8 6.5 11.0 6.5 12.5

-

23.5

-

5.5 16.0

-

7.3

67.1

Source: Matsuno et al. (1973).

red of free astaxanthin. Although little information on carotenoproteins of spiny lobsters is available, crustacyanin, the blue astaxanthin-protein present in the carapace of lobsters Homarus spp., has been extensively studied (Thommen, 1971; Britton et al., 1982). In Homarus crustacyanin, astaxanthin seems to be ionically bonded to a tryptophan residue in the hydrophobic pocket of the apoprotein (Clarke et al., 1990; Zagalsky et al., 1991). Cooking denatures the apoprotein and liberates the astaxanthin. The exoskeleton of boiled lobsters is therefore red and this process may hold true for spiny lobster as well. Crustaceans cannot synthesize carotenoids de novo but can convert most dietary carotenoids into astaxanthin by oxidative metabolic pathways: /3-carotene + echinenone + canthaxanthin + adonirubin (phoenicoxanthin) t astaxanthin, and zeaxanthin -+ adonixanthin (4ketozeaxanthin) t astaxanthin (Matsuno, 1991).

34.2.2

Black discoloration

Many crustaceans are susceptible to surface darkening through melanosis or ‘black spot’. This darkening is caused by the action of polyphenoloxidase (E.C.1.14.18.1), also known as tyrosinase, polyphenolase, phenolase, catechol oxidase, cresolase and catecholase, which is widely distributed in nature (Chen et al., 1991).

621

Colour and Taste

With respect to phenoloxidase enzymes of spiny lobsters, studies have been made into their mode of activation and characterization in the cuticle of Florida spiny lobster Panulirus argus (Ferrer et al., 1989a), their levels in relation to season and moulting stage (Ferrer et al., 1989b), their immunological and spectropolarimetric character (Rolle et al., 1990), and comparison of enzyme activity between Florida spiny lobsters and the Western Australian P. cygnus (Chen et al., 1991). Spiny lobsters are generally kept alive after capture until processing or cooking, but in a few countries it is common practice to tail lobsters soon after capture. The lobster tails are then washed with seawater and stored in ice or frozen. In some tails, black spots gradually appear in the broken and bruised, hard and soft segments of the ventral cuticle. Usually those spots are small, not developed and do not reach the inner muscle. The black discoloration, however, is apt to indicate spoilage of the products to the consumer. Black spot formation in the tails of Brazilian spiny lobsters P. argus and P . laevicauda and the Japanese P . japonicus has been investigated in detail by Ogawa et al. (1983a, b, 1984, 1985). The commercial practice of handling lobsters on board in Brazilian local fisheries is as follows: after capture, the live lobsters are tailed and the tails immersed in iced seawater containing 1% NaHS03 for 10 min. Then, they are put in a Styrofoam (8-cm thick walls) insulated hold, and covered with crushed ice, each day's catch being separated by a polyethylene sheet. Fishing trips last from 3 to 15 days. Table 34.2 shows the incidence of the black discoloration at local fishery ports (Ogawa et al., 1983b). Tails of P. laevicauda showed a higher discoloration rate than those of P . argus. This is probably due to the species specificity in phenoloxidase activity (Chen et al., 1991) and in metabolism related to the moulting cycle (Ogawa et al., 1984). Reducing substances such as NaHS03 can prevent Table 34.2 Incidence of black discolorationin the tails of two species of spiny lobster at local fishery ports in Brazil ~~

Port name Panulirus argus Areia Brancaa Aracatib Aracatic Panulirus laevicauda Areia Brancaa Aracatib Aracati'

~~

~~

~

Total no. of tails

No. of discoloured tails

Discoloration percentage

2550 6473 6688

0 259 197

0 4.0 2.9

4164 3741 7090

600 252 773

14.4 6.7 10.9

Source: Ogawa et al. (1983b). aTails treated with NaHS03: 3-8 days of fishing. ?ails treated with NaHS03: 4-12 days of fishing. Tails untreated with NaHS03: 4-12 days of fishing.

628 Spiny Lobsters: Fisheries and Culture crustaceans from discoloration, but Table 34.2 indicates the NaHS03 treatment to be ineffective for P . argus. In this context, Ogawa et al. (1983a) reported that good handling of lobsters by avoiding physiological injury such as trauma, blows or stress after capture is important in the prevention of black spot development. The black discoloration itself has no relationship to the quality of tails as food, because black spots appear in ice-stored tails regardless of storage at low temperature, and thawing under relatively low temperature helps to prevent discoloration. Melanosis, however, seems to be inevitable for lobsters once injured in the live state even if handled using the low-temperature treatment (Ogawa et al., 1985). Thus, to inhibit darkening, lobsters should preferably be killed without physical injury or physiological stress, then handled carefully. Damaged lobsters should be quick-frozen, followed by thawing at low temperature and immediate cooking.

34.3

Taste

In order to identify the taste-active components in the tail muscle of Japanese spiny lobster P . japonicus, Shirai et al. (1996) performed a detailed analysis of its extractive components, such as free amino acids, nucleotides and related compounds, quaternary ammonium bases and minerals. The analysis was followed by sensory taste tests using an artificial extract prepared with 34 pure chemicals in accordance with the analytical data. The results obtained are summarized and discussed in the following two sections. 34.3.1

Extractive components

The analytical results are shown in Table 34.3, in which only the major nitrogenous components are given. The muscle is rich in such free amino acids as taurine, glutamine, glycine, alanine, arginine and proline, and in such quaternary ammonium bases as glycine betaine, homarine and trimethylamine oxide (TMAO). The sexual difference in the composition of extractive components is not significant. Among the extractive components analysed, glycine is the most prominent, exceeding 13 mmo1/100 g (more than 1% of the muscle). The abundance of glycine as well as glycine betaine in the muscle was also pointed out previously by Hujita et al. (1972) and Shinagawa et al. (1995). As for nucleotides, adenosine 5’-triphosphate (ATP), adenosine 5’-diphosphate (ADP), adenosine 5’-monophophate (AMP) and inosine 5’-monophosphate (IMP) are detected more or less. 34.3.2

Taste-active components

The sensory taste tests revealed that glutamic acid, glycine, alanine, arginine, proline, glycine betaine, TMAO, AMP, IMP, sodium, potassium, chloride and phosphate

Colour and Taste

629

Table 34.3 Nitrogenous extractive components in the tail muscle of Japanese spiny lobster Panulirusjaponicus (mmo1/100 g)

Male

Female

1.61 0.06 1.57 15.86 1.03 0.21 0.19 2.96 0.31 0.99

1.25 0.12 1.27 13.74 1.39 0.26 0.21 3.42 0.24 1.54

0.03 0.28 0.26 0.29 0.10

0.03 0.34 0.15 0.30 0.24

4.27 1.11 0.08 3.75

3.37 1.36 0.12 3.75

Free amino acids

Taurine Glutamic acid Glutamine Glycine Alanine Valine Methionine Arginine Hydroxyproline Proline Nucleotides and related compounds

ATP ADP AMP IMP Inosine Quaternary ammonium bases

Glycine betaine Homarine Trigonelline TMAO ~~

~

Source: Shirai et al. (1996). Values are average of five specimens. See text for abbreviations.

ions contributed to produce the characteristic taste of Japanese spiny lobster. It is worth noting that these taste-active components are quite similar to those found on snow crab and scallop (Konosu et al., 1987a, b). The taste of Japanese spiny lobster is characterized by sweetness. Glycine, alanine, proline, glycine betaine and probably TMAO are responsible for this. Hujita et al. (1972) stated that the glycine content as well as the total amount of sweet amino acids, such as glycine, alanine, proline and serine, in the muscle of shrimps, prawns and Japanese spiny lobster were correlated with the palatability of those crustaceans. The contribution of glycine and alanine to the sweetness and the overall acceptance has been confirmed sensorially on snow crab, which has much in common with Japanese spiny lobster in free amino acid composition (Konosu et al., 1987a).

630 Spiny Lobsters: Fisheries and Culture Although the concentration of glutamic acid is very low in the muscle of Japanese spiny lobster (Table 34.3), it is most likely to produce .the umarni taste synergistically with AMP and IMP, and thereby to elevate the overall acceptance, as it does in snow crab and scallop (Konosu et al., 1987a, b). The greater part of free arginine found in the muscle of Japanese spiny lobster (Table 34.3) is derived from phosphoarginine. Arginine is a bitter amino acid, but omission tests, using synthetic extracts simulating snow crab and scallop extracts, showed that it did not impart bitterness, but instead gave continuity, complexity and fullness in flavour, leading to high overall acceptance (Konosu el al., 1987a, b). A similar role of arginine in contributing to the distinctive taste of Japanese spiny lobster is likely. Michikawa & Konosu (1995) found that the bitterness of arginine was decreased by glutamic acid, AMP and NaCl, NaCl being the most effective.

34.3.3

Effects of seawater concentration on taste-active components

Seawater concentration affects levels of free amino acids and betaines in the tail muscle of Japanese spiny lobster (Shinagawa et al., 1995) and therefore influences flavour. The lobster is stenohaline, but it survived for at least 24 h in diluted (75%) and concentrated (125%) seawater. After the animals were acclimated at 75, 100 and 125% seawater for 24 h, the muscle was analysed for free amino acids and betaines. As shown in Table 34.4, the total amounts of free amino acids and betaines varied depending on the environmental salinity, with variations in glycine and glycine betaine, both of which are sweet substances, being the most pronounced. This suggests that the taste of the muscle can be improved by immersing the lobster in concentrated seawater for a short time.

34.4

Conclusions

As described above, the coloration of the exoskeleton of spiny lobsters is completely dependent on their dietary carotenoids. For their culture on a commercial scale, therefore, provision of a suitable carotenoid source in diets is essential in yielding pigmentation of spiny lobsters close to that seen in nature. Taste-active components of spiny lobsters may also be influenced by diet, as well as by other factors, e.g. growth, moulting stage, sexual maturity, season and freshness (Konosu & Yamaguchi, 1982). However, information on these problems is still poor. An extensive study of cultured lobsters from the food chemical viewpoint is required.

Colour and Taste

631

Table 34.4 Effects of seawater concentration on free amino acids and betaines in the tail muscle of Japanese spiny lobster Panulirus japonicus (mmol/kg H20) Concentration of seawater (%) Free amino acids Taurine Glutamic acid Proline Glycine Alanine Arginine Others Total Betaines Glycine betaine Homarine Trigonelline Total Moisture of muscle (%)

75

100

125

17.5 1.2 25.6 196.9 26.2 60.7 23.6 351.7

20.7 2.4 27.3 259.9 21.9 63.4 28.9 424.5

33.6 2.0 31.0 326.3 25.1 81.6 35.9 535.5

86.1 30.0 1.3 117.4 76.9

78.1 28.7 1.o 107.8 76.9

151.4 49.7 1.6 202.7 71.1

Source: Shinagawa et al. (1995).

References Britton, G., Armitt, G.M. & Lau, S.Y.M. (1982) Carotenoproteins. In Curotenoid Chemistry & Biochemistry (Ed. by G. Britton & T.W. Goodwin), pp. 237-51. Pergamon Press, Oxford, UK. Chen, J.S., Rolle, R.S., Marshall, M.R. & Wei, C.I. (1991) Comparison of phenoloxidase activity from Florida spiny lobster and Western Australian lobster. J. Food Sci., 56, 15k-7, 160. Clarke, J.B., Eliopoulos, E.E., Findlay, J.B.C. & Zagalsky, P.F. (1990) Alternative ligands as probes for the carotenoid-binding site of lobster carapace crustacyanin. Biochem. J., 265, 919-21. Ferrer, O.J., Koburger, J.A., Otwell, W.S., Gleeson, R.A., Simpson, B.K. & Marshall, M.R. (1989a) Phenoloxidase from the cuticle of Florida spiny lobster (Panulirus urgus): mode of activation and characterization. J. Food Sci., 54, 63-7. Ferrer, O.J., Koburger, J.A., Simpson, B.K., Gleeson, R.A. & Marshall. M.R. (1989b) Phenoloxidase levels in Florida spiny lobster (Panulirus argus): relationship to season and molting stage. Comp. Biochem. Physiol., 93B,595-9. Hujita, M., Endo, K. & Simidu, W. (1972) Studies on muscle of aquatic animals - XXXXVI. Free amino acids, trimethylamine oxide and betaine in shrimp muscle. Mem. Fuc. Agric. Kinki Univ., 5, 61-7 (in Japanese with English summary). Konosu, S. & Yamaguchi, K.(1982) The flavor components in fish and shellfish. In Chemistry and Biochemistry of Marine Food Products (Ed. by R.E. Martin, G.J. Flick, C.E. Hebard & D.R. Ward), pp. 367-404. Avi Publ. Co., Westport, CT, USA.

632 Spiny Lobsters: Fisheries and Culture Konosu, S., Hayashi, T. & Yamaguchi, K. (1987a) Role of extractive components of boiled crab in producing the characteristic flavor. In Umami: A Basic Taste (Ed. by Y . Kawamura & M.R. Kare), pp. 235-53. Marcel Dekker, New York, USA. Konosu, S., Watanabe, K. & Yamaguchi, K. (1987b) Acceptance effects of taste components. Sensory analysis of taste-active components in the adductor muscle of scallop. In Food Acceptance and Nutrition (Ed. by J. S o h , D.A. Booth, R.M. Pangborn & 0. Raunhardt), pp. 143-55. Academic Press, London, UK. Matsuno, T. (1991) Xanthophylls as precursors of retinoids. Pure Appl. Chem., 63, 81-8. Matsuno, T., Kusumoto, T., Watanabe, T. & Ishihara, Y. (1973) Carotenoid pigments of spiny lobster. Nippon Suisan Gakkaishi, 39,43-50 (in Japanese with English summary). Michikawa, K. & Konosu, S. (1995) Sensory identification of effective components for masking bitterness of arginine in synthetic extract of scallop. Nippon Shokuhin Kagaku Kogaku Kaishi, 42, 982-8 (in Japanese with English summary). Ogawa, M., Kurotsu, T., Ochiai, I. & Kozima, T.T. (1983a) Mechanism of black discoloration in spiny lobster tails stored in ice. Nippon Suisan Gakkaishi, 49, 1065-75. Ogawa, M., Magalhles-Neto, E.O., Aguiar-Jr., 0. & Kozima, T.T. (1984) Incidence of melanosis in the integumentary tissue. Nippon Suisan Gakkaishi, 50, 47 1-5. Ogawa, M., Magalhiies-Neto, E.O., Viana, E.M.Q. & Kozima, T.T. (1985) Influence of freezing, storing and thawing on melanin formation in lobster tails. Nippon Suisan Gakkaishi, 51, 127-31. Ogawa, M., Meneses, A.C.S., Perdigrio, N.B. & Kozima, T.T. (1983b) Influence of storage conditions and quality evaluation of discolorated spiny lobster tails. Nippon Suisan Gakkaishi, 49, 975-82. Rolle, R.S., Marshall, M.R., Wei, C.I. & Chen, J.S. (1990) Phenoloxidase forms of the Florida spiny lobster: immunological and spectropolarimetric characterization. Comp. Biochem. Physiol., 97B,483-9. Shinagawa, A., Suzuki, T. & Konosu, S. (1995) Preliminary studies on the effects of salinity on intracellular nitrogenous osmolytes in various tissues and hemolymph of the Japanese spiny lobster, Panulirus japonicus (von Siebold, 1824). Crustaceana, 68, 129-37. Shirai, T., Hirakawa, Y., Koshikawa, Y., Toraishi, H., Terayama, M., Suzuki, T. & Hirano, T. (1996) Taste components of Japanese spiny and shovel-nosed lobsters. Fish. Sci., 62, 283-7. Thommen, H. (1971) VIII. Metabolism. In Carotenoids (Ed. by 0. Isler), pp. 63748. Birkhauser Verlag, Basel, Switzerland. Zagalsky, P.F., Eliopoulos, E.E. & Findlay, J.B.C. (1991) The lobster carapace carotenoprotein, a-crustacyanin. A possible role for tryptophan in the bathochromic spectral shift of proteinbound astaxanthin. Biochem. J., 214, 79-83.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 35 H. SUGITA and Y. DEGUCHI

Department of Marine Science and Resources, Nihon

University, Fujisawa, Kanagawa 252-8510, Japan

35.1

Introduction

Although much literature on transporting live fish is available, little is known about the spiny lobster (Morooka, 1966; Yamazaki, 1967; Stickney, 1979; Solomon & Hawkins, 1981; McLarney, 1984; Homma, 1990; Sugita & Deguchi, 1990; Taylor et al., 1997). When live spiny lobsters are to be sent to another place such as fish farms, local restaurants, wholesale food markets or large processing plants, it is necessary to ship the animals so that they arrive in good condition. In the context of live transport of spiny lobsters, potential stressors include the capture and landing of the lobsters, post-capture transfers, induction of vigorous escape behaviour (tail flips), physical damage (e.g. limb loss, blood loss), interaction between lobsters, low water quality in recirculating holding tanks, and exposure of the lobsters to air. Therefore, it is important to understand the mechanisms of stress and to document convenient indicators of levels of stress in the live transport of lobsters (Taylor et al., 1997).

35.2

Containers

Like other aquatic animals, spiny lobsters can be commercially transported using specially constructed trucks and tankers fitted with a supply of compressed air or oxygen for large-scale operations, and also by using fibreglass containers, or polythene or polyvinyl chloride (PVC) bags inside rigid containers with seawater on a small scale. In addition, spiny lobsters can be transported in cardboard or polystyrene foam boxes with a suitable packing material such as sawdust or expanded polystyrene. Sawdust is widely used because of its low thermal conductivity, light weight, easy ventilation and low cost (Watanabe, 1990). The thickness of waterproof cardboard and polystyrene foam boxes must be more than 7 and 20 mm, respectively. Deep-frozen blocks of ice or special cooling bags, insulated with thick plastic bags (270 pm) and paper, are used to keep the temperature inside the box cool. Finally, the box is lined tightly and water-proofed, especially for air transport, but ventilation should be provided through several holes (23 mm) in the box cover. The weight of the container, including animals and cooling and packing materials, is usually 10-20 kg for air transport (Ishimatsu, 1990).

633

634 Spiny Lobsters: Fisheries and Culture 35.3 35.3.1

Biological factors Bacteria

Aquatic animals always take a great number of bacteria into their gut from water, sediment and/or food. In addition, they are always in contact with a large number of bacteria in the water and sediment. As a result, the animals harbour bacteria on their body surface and gills, and in the intestinal tract. However, most of these bacteria are temporary residents, frequently because of incompatile physical and chemical conditions, lethal interactions between bacteria, and/or the immune response of the host animals. Certain bacteria are present for a relatively long term and they form the microfora specific to each site of the host animals. Considerable information has been obtained with respect to the microflora of aquatic vertebrates including fish, and some knowledge is also available for Crustacea (Sugita et al., 1987; Sugita & Deguchi, 1988; Cahill, 1990). Figure 35.1 shows the microflora associated with the gill and gut content of five specimens of freshly caught Japanese spiny lobster, Panulirus japonicus (Sugita et al., 1986, 1987). In the lobster’s gill, population densities of bacteria were 3.2 x lo6 to 1.2 x lo7 colony-forming units (CFU)/g, and the genera Vibrio and Pseudomonas were predominantly isolated from all specimens, whereas Flavobacterium, Micrococcus, coryneforms and anaerobic Bacteroidaceae were minor components with a low frequency of occurrence. In the gut contents, 9.5 x lo7 to 1.3 x lo9 CFU/g of bacteria were counted, and the genus Vibrio was the dominant colonist, with Pseudomonas, Staphylococcus, coryneforms and anaerobic Streptococcus isolated from 2040% of specimens as minor colonists. Of 518 strains of Vibrio isolated from the spiny lobster, 69 strains were tentatively identified as V. alginolyticus, a causative agent of crustacean vibriosis (Elston, 1989). Vibrio alginolyticus was also isolated from normal individuals of coastal crabs, Thalamita prymna and Plagusia dentipes (Sugita et al., 1987). These results strongly suggest that pathogenic bacteria colonize the gills and gut of healthy Crustacea, including spiny lobsters, and may cause opportunistic infectious diseases when the self-defence mechanisms are suppressed during transport. When spiny lobster are transported in a suitable container with seawater, these microorganisms are excreted as faeces, mucus and gill fragments from the animals; aerobic and facultative anaerobic bacteria such as Pseudomonas and Vibrio can then proliferate rapidly and consume dissolved oxygen exclusively. These facts strongly suggest that healthy individuals of spiny lobster should be starved for 1-2 days before transport to minimize the amount of faeces excreted during transport, and the temperature inside the package should be kept low to suppress the growth of bacteria. In addition, seawater and packing materials such as sawdust should be sterilized by an ozonizer if they have already been used.

Shipping

Bacteroldaceae

I

635

I

0

0 000 0

0 0 5

6

. 7

8

9

10

Bacterial Number (Log CFUIg)

Fig. 35.1 Microflora of (a) the gill and (b) gut content of five specimens of Japanese spiny lobster, Panulirus japonicus. Note differing horizontal axes. CFU, colony-forming units.

35.3.2

Bactericidal activity of lobster’s sera

It is known that Crustacea possesses humoral and cellular defence mechanisms like those of vertebrates and other invertebrates (Evans et af., 1969; McKay et af., 1969; Paterson & Stewart, 1974; Smith & Pistole, 1985; Ueda et af., 1990, 1991; Bachkre et af., 1995; Chisholm & Smith, 1995). Paterson et al. (1976) reported that noninducible agglutinins, inducible bactericidins and precipitins, together with phagocytosis of blood cells, act co-operatively to protect American lobster, Homarus arnericanus, from bacterial pathogens. Spiny lobsters also possess naturally occurring bactericidin which kills bacterial cells invading the haemolymph. Therefore, the bactericidal activity of haemolymph may become an excellent indicator to evaluate the health condition of Japanese spiny lobsters. The bactericidal activity of crustacean haemolymph (serum) was determined by Ueda et af. (1990) as follows.

636 Spiny Lobsters: Fisheries and Culture Haemolymph was collected by a sterile syringe from the pericardial sinus of spiny lobster and then transferred into a sterile test-tube. Serum was obtained by allowing the haemolymph to clot and breaking the clotting with a sterile glass stick, followed by centrifugation at 4000 rpm for 15 min. Vibrio sp. strain V-8, which was isolated from the gut content of P . dentipes, was used as the target cell because this strain is remarkably susceptible to coastal crustacean sera. The strain was aerobically incubated on agar plates at 25°C for 2 days. After being harvested by centrifugation, cells were washed three times with phosphate-buffered saline (containing 2% NaCl, pH 7.0; PBS) and then prepared at a concentration of 5 x lo4 cells/ml. To determine the bactericidal activity, 0.1 ml of live cell suspension of target bacteria was added to 0.7 ml of PBS plus 0.2 ml of serum, and the mixture was incubated at 25°C for 2 h. A control, in which the same volume of the bacterial suspension was added to 0.9 ml of PBS, was also incubated similarly. Surviving bacteria were counted on the agar plate after incubation at 25°C for 2 days. Bactericidal activity was calculated as loglo CFU/ml in the control minus loglo CFU/ml with serum. Using the bactericidal activity, Ueda et al. (1990) examined the effect of various factors on the health condition of Japanese spiny lobsters. Star vat ion

Serum bactericidal activity of individuals reared for 14 days at temperatures ranging from 13 to 28"C, with or without feeding, was determined. As a result, the activity decreased significantly in starved individuals at 25-28"C, whereas no special changes were observed in both the fed individuals and almost all the individuals kept at 13-20°C. These results strongly suggest that starvation for a few days is not especially stressful to the spiny lobster at temperatures below 20°C. Salinity

In general, spiny lobsters such as P . japonicus and Jasus lalandii can be reared at a salinity of 34-36%0 (Kittaka, 1988; Kittaka & Kimura, 1989). Therefore, Japanese spiny lobsters were held in 70% seawater (salinity 24.2%0)at 20°C for 18 h, and the serum bactericidal activity was determined before and after the exposure to low salinity. As a result, 15 out of 18 specimens showed a decrease in bactericidal activity. This result supports the report of Nishimura et al. (1972), suggesting that the lethal salinity for Japanese spiny lobster is around 24%0. Transport

Japanese spiny lobsters were stored in containers (20 litres) including air, seawater or sawdust as packing materials, and transported 280 km for 8 h by car. Figure 35.2a shows the result of serum bactericidal activity of the animals before and after the

Shipping

637

transport. The activity was not significantly influenced when the animals were stored in seawater with aeration, but it decreased prominently in specimens kept in sawdust and only in air. Similar results were observed in Japanese (Kuruma) prawn, Penueus juponica, and swimming crab, Portunus trituberculutus (Fig. 35.2b). Taylor & Waldron (1997) also reported that, when undisturbed specimens of southern rock lobster, Jusus edwurdsii, are exposed to air, their oxygen uptake is approximately halved, despite a doubling in ventilation rate and oxygen content of air about 35 times higher than that of water. These results strongly suggest that the spiny lobster should be transported in seawater, with aeration, if economic problems are resolved.

.-c* 5 .c 0

-

m m 0

.-0 t

2

1

L

0

m m 0

Seawater

Sawdust

Air

3-

* .-c> .-c 0

-mm

c3

Before transpolt Atter transport

2-

E 0

.-

L

2 0 m m

1-

O+

Seawater Sawdust Japanese prawn

Seawater Sawdust Swimming crab

Fig. 35.2 Serum bactericidal activity of individuals transported in a container with seawater, sawdust and air as packing materials (each bar is the mean of three to five animals). (a) Japanese spiny lobster, Punulirus japonicus; (b) Japanese (Kuruma) prawn, Penaeus japonicus, and swimming crab, Portunus trituberculatus.

638 Spiny Lobsters: Fisheries and Culture 35.4 35.4.1

Environmental factors Dissolved oxygen

To maintain the spiny lobster in healthy conditions, sufficient dissolved oxygen is essential. Morooka (1966) reported that the oxygen consumption rate of Japanese spiny lobsters was 14.4 and 79 ml/kg/h at 12 and 27"C, respectively. Moreover, Nimura & Inoue (1969) found that the incipient lethal level is about 1.0 ml 0 2 / 1 in the Japanese spiny lobster. Disturbed lobsters have a high demand for oxygen, and despite the high gill ventilation rate typical of stressed crustaceans, even a modest fall in oxygen concentration in water curtails the rate of oxygen uptake. Haemolymph oxygen concentration of western rock lobster, Panulirus cygnus, falls when the concentration of oxygen in the environment falls, and when crustaceans are taken from the water for extended periods, and this in turn influences the function of the respiratory pigment, haemocyanin (Paterson & Spanoghe, 1997). Oxygen concentrations can be maintained by bubbling compressed or pumped oxygen or air, or by surface agitation. Effectiveness is increased by maximizing the surface area, or by providing an atmosphere of oxygen above the water. For this purpose, a large space of about four times the water volume must be left in the container to contain the air or oxygen.

34.4.2

Temperature

Temperature influences the activity and oxygen consumption rate of the animals and microorganisms, and also the oxygen-carrying capacity of the water. In addition, high temperature may be directly lethal to the animal. Ueda (1989) and Kittaka & Kimura (1989) suggested that the upper limit of water temperature is 28°C for Japanese spiny lobsters, a value corresponding to that for the American lobsters, H . americanus (lethal values of 231°C) (Van Olst et al., 1980). However, cold temperate species of spiny lobsters prefer lower temperatures, e.g. 18-20°C for J . lalandii (Saisho, 1985; Kittaka, 1988). Spanoghe & Bourne (1997) reported that three factors, holding time in export cartons, ambient temperature within the export cartons and chilling period before packing lobsters, had the greatest influence on the rate of morbidity plus mortality of western rock lobster. Chipped or crushed ice is satisfactory for a short journey, although deep-frozen blocks of ice, or special cooling bags, are safer and last for a very long time.

35.5

Conclusions

There is an increasing demand for the transportation of live Crustacea, especially lobsters and spiny lobsters (about 2400 t of live spiny lobster were shipped into

Shipping

639

Japan, mainly from Australia and New Zealand, in 1991), and equipment and devices have been developed (Oshikata, 1994). In general, evaluation of this technology was based empirically on the survival rate of the Crustacea. However, the ultimate purpose of this technology has to be to minimize the stress on the Crustacea during transport. To do so, suitable indicators to evaluate the condition of Crustacea, including haemolymph components and haemocytes, should be developed in the near future (Paterson & Spanoghe, 1997; Paterson et al., 1997; Jussila et al., 1997).

References Bachere, E., Mialhe, E., Noel, D., Boulo, V., Morvan, A. & Rodriguez, J. (1995) Knowledge and research prospects in marine mollusc and crustacean immunology. Aquaculture, 132, 17-32. Cahill, M.M. (1990) Bacterial flora of fishes: a review. Microbial Ecol., 19, 21-41. Chisholm, J.R.S. & Smith, V.J. (1995) Comparison of antibacterial activity in the hemocytes of different crustacean species. Comp. Biochem. Physiol., llOA, 3945. Elston, R. (1989) Bacteriological methods for diseased shellfish. In Methods f o r the Microbiological Examination of Fish and Shellfish (Ed. by B. Austin & D.A. Austin), pp. 187-215. Ellis Horwood, Chichester, UK. Evans, E.E., Cushing, J.E., Sawyer. S., Weinheimer, P.F., Acton. R.T. & McNeely J.L. (1969) Induced bactericidal response in the California spiny lobster Panulirus interruptus. Proc. SOC. Exp. Biol. Med., 132, 11 1-14. Homma, A. (Ed.) (1990) An Encyclopedia on Live Fish. Fuji Technology Press, Tokyo, Japan, 712 pp. (in Japanese). Ishimatsu, N. (1990) Air transport. In An Encyclopedia on Live Fish (Ed. by A. Homma), pp. 201-1 7. Fuji Technology Press, Tokyo, Japan (in Japanese). Jussila, J., Jago, J., Tsvetnenko, E., Dunstan, B. & Evans, L.H. (1997) Total and differential haemolymph counts in western rock lobsters (Panulirus cygnus George) under post-harvest stress. Mar. Freshwat. Res., 48, 863-7. Kittaka, J. (1988) Culture of the palinurid Jasus lalandii from egg stage to puerulus. Nippon Suisun Gukkaishi, 54(1), 87-93. Kittaka, J. & Kimura, K (1989) Culture of the Japanese spiny lobster Panulirus juponicus from egg to juvenile stage. Nippon Suisan Gakkaishi, 55(6), 963-70. McKay, D., Jenkin, C.R. & Rowley, D. (1969) Immunity in the invertebrates. I. Studies on the naturally occurring haemagglutinins in the fluid from invertebrates. Aust. J . Exp. Biol. Med. Sci., 47, 125-34. McLarney, W. (1984) The Freshwater Aquaculture Book: A Handbook for Small Scale Fish Culture in North America, pp. 296322. Hartley & Marks, Vancouver, Canada. Morooka H. (1966) On the Live Fish Transport. Ishizaki Shoten, Tokyo, Japan, 47 pp. (in Japanese). Nimura, Y.& Inoue, M. (1969) Oxygen uptake rate of the Japanese spiny lobster as related to the environmental oxygen concentration. Bull. Jpn. SOC.Sci. Fish., 35(9), 852-61. Nishimura, K., Yoshida, K. & Saito, M. (1972) Tolerance of low salinity water by the Japanese spiny lobster, Panulirus japonicus. Suisanzoshoku, 20(2), 79-84 (in Japanese). Oshikata, Y. (1994) Marketing and distribution in Japan. In Spiny Lobster Management: Current Situation and Perspectives (Ed. by B.F. Phillips, J.S. Cobb & J. Kittaka), pp. 517-25. Fishing News Books, Blackwell Scientific Publications, Oxford, UK.

640 Spiny Lobsters: Fisheries and Culture Paterson, B.D. & Spanoghe, P.T. (1997) Stress indicators in marine decapod crustaceans, with particular reference to the grading of western rock lobsters (Panulirus cygnus) during commercial handling. Mar. Freshwat. Res., 48, 829-34. Paterson, W.D. & Stewart, J.E. (1974) In vitro phagocytosis by hemocytes of the Amcrican lobster (Homarus americanus). J . Fish. Res. Ed Can., 31, 1051-6. Paterson, B.D., Grauf, S.G. & Smith, R.A. (1997) Haemolymph chemistry of tropical rock lobsters (Panulirus ornatus) brought onto a mother ship from a catching dinghy in Torres Strait. Mar. Freshwat. Rex, 48, 835-8. Paterson, W.D., Stewart, J.E. & Zwicker, B.M. (1976) Phagocytosis as a cellular immune response mechanism in the American lobster, Homarus americanus. J. Invertebr. Pathol., 27, 95-104. Saisho, T. (1985) Distribution of rock lobsters along the coast of South Africa. Mar. Sci. Monthly, 17(6), 35660 (in Japanese). Smith, R.H. & Pistole, T.G. (1985) Bactericidal activity of granules isolated from amoebocytes of the horseshoe crab, Limulus polyphemus. J . Invertebr. Pathol., 45, 272-5. Solomon, D.J. & Hawkins, A.D. (1981) Fish capture and transport. In Aquarium Systems (Ed. by A.D. Hawkins), pp. 197-221. Academic Press, London, UK. Spanoghe, P.T. & Bourne, P.J. (1997) Relative influence of environmental factos and processing techniques on Panulirus cygnus morbidity and mortality during simulated live shipments. Mar. Freshwat. Res., 48, 839-44. Stickney, R.R. (1979) Principles of Warmer Aquaculture, pp. 300-19. John Wiley & Sons, New York, USA. Sugita, H. & Deguchi, Y. (1988) Intestinal microfloras in tetrodotoxin-bearing organisms, with special references to tetrodotoxin-producing bacteria. In Recent Advances in Tetrodotoxin Research (Ed. by K. Hashimoto), pp. 65-75. Koseisha Koseikaku, Tokyo, Japan (in Japanese). Sugita, H. & Deguchi, Y. (1990) Live fish transportation and preservation. In Price Formation and Quality Control of Mariculture Products (Ed. by K. Hirayama), pp. 10&8. Koseisha Koseikaku, Tokyo, Japan (in Japanese). Sugita, H., Ueda, R., Berger, L.R. & Deguchi, Y. (1987) Microflora in the gut of Japanese coastal Crustacea. Nippon Suisan Gakkaishi, 53(9), 1647-55. Sugita, H., Ueda, R. & Deguchi, Y. (1986) An anaerobic bacterium isolated from Japanese spiny lobster Panulirus japonicus. Food Microbiol., 3(4), 379-85. Taylor, H.H. & Waldron, F.M. (1997) Respiratory responses to air-exposure in the southern rock lobster, Jasus edwardsii (Hutton) (Decapoda: Palinuridae). Mar. Freshwat. Res., 48, 889-97. Taylor, H.H., Paterson, B.D., Wong, R.J. &Wells, R.M.G. (1997) Physiology and live transport of lobsters: report from a workshop. Mar. Freshwat. Res., 48, 817-22. Ueda, R. (1989) A Study on Naturally Occurring Agglutinin and Bactericidal Activity of the Hemolymph of Coastal Crustacea. Ph.D. thesis, Nihon University, Japan, 178 pp. (in Japanese). Ueda, R.,Sugita, H. & Deguchi, Y. (1990) The serum bactericidal activity: a possible indicator as crustacean health conditions. Proc. Fourth Pacific Congr. Mar. Sci. Technol., Tokyo, Vol. 1, pp. 33340. Ueda, R., Sugita, H. & Deguchi, Y. (1991) Naturally occurring agglutinin in the hemolymph of Japanese coastal Crustacea. Nippon Suisan Gakkaishi, 57( l), 69-78. Van Olst, J.C., Carlberg, J.M. & Hughes, J.T. (1980) Aquaculture. In The Biology and Management ofLobsters, Vol. 2 (Ed. by J.S. Cobb & B.F. Philips), pp. 333-84. Academic Press, New York, USA. Watanabe, T. (1990) Spiny lobster. In An Encyclopedia on Live Fish (Ed. by A. Homma), pp. 524-7. Fuji Technology Press, Tokyo, Japan (in Japanese). Yamazaki, T. (1967) The Method of Transporting Live Trout. Ishizaki Shoten, Tokyo, Japan, pp. 1-55 (in Japanese).

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 36

Export Marketing of Australian and New Zealand Spiny Lobsters R.N. STEVENS

Western Australian Fishing Industry Council, P . 0 . Box 55, Mount

Hawthorn, Western Australia 6915. Australia

D. SYKES

New Zealand Rock Lobster Industry Council, P.O. Box 24901, Wellington, New

Zealand

36.1

Introduction

Australia and New Zealand have a number of common markets for spiny lobsters, which give rise to both competitive and complementary marketing strategies. Western rock lobster (Panulirus cygnus) and southern rock lobster (Jams edwardsii) dominate production. There is also a small but significant production of tropical lobster (mainly Panulirus ornatus) and subtropical lobster (mainly Jams verreauxi). The fisheries are major components of each country’s seafood exports. Lobsters are sold alive, frozen whole raw, frozen whole cooked and as frozen tails. Only Western Australia produces significant quantities of whole cooked lobster, with about 5000 t annually. Live exports account for just under half of the Australian production at about 7000 t each year, and 95% of the New Zealand production, being 2667 t in the 1998 calendar year.

36.2

Production and management

Production from the both countries is managed for sustainability, at about 19 000 t p.a., representing 28% of the world harvest between 1992 and 1996 (FAO, Rome, cited in Cicerello, 1998), with Australia and New Zealand being the largest and fifth largest producers, respectively. Spiny lobster management in Australia is largely under State jurisdiction. In New Zealand the Ministry of Fisheries (MFish) has oversight of rock lobster fisheries management. In both countries users of the resource are actively involved in delivering annual research and management planning advice to their ministers responsible for fisheries. Management regimes include both input and output controls. In New Zealand the fishery is controlled via area and individual transferable quotas, overlying residual input controls. The Tasmanian and south-eastern zones of South Australia have also adopted quota management, with a change in Victoria from input to output controls, under review at May 2000. All lobster fisheries are subject to input

64 1

642 Spiny Lobsters: Fisheries and Culture

controls, including minimum sizes, protection of breeding females, licence and gear restrictions. Lobster fisheries in the tropics, and the New South Wales, South Australian northern zone and Western Australian fisheries are input controlled only. There are different minimum size regulations for lobster in the South Australian, Victorian and Tasmanian jurisdictions, but these three states meet regularly to maintain a commonality of regulation as far as is possible.

36.2.1

New Zealand

Red rock lobster (J.edwardsii) is the predominant species. The primary management regime sets total allowable catches (TACs) for rock lobster, within which a total allowable commercial catch (TACC) is set. The TACC is apportioned as individual transferable quotas (ITQs), which are issued in perpetuity as a percentage of the TACC of a region and expressed as a tonnage. In 1999 the TACC was 2 848 554 kg plus 40 300 kg of packhorse lobster (J. verreauxz]. Management issues are discussed elsewhere in this book. The fisheries legislation makes no particular reference to marketing issues, but regulations impact on the marketing of lobster. For example the New Zealand quota-managed fisheries operate in the winter months to take advantage of the fact that the Australian fisheries are generally closed during that period (see Fig. 36.1~). There is a prohibition on the harvesting of soft-shelled, berried or damaged lobsters. Commercial fishermen must land all lobsters live, except for the Southland (CRA 8, see Chapter 2) where a tailing at sea exemption applies subject to rigorous hygiene requirements. Each rock lobster pot is required to have specified numbers of escape gaps and/or mesh size. Non-commercial catch is controlled by a daily bag limit of six lobsters per day per person. A limit on the number of pots used by recreational fishermen applies in some regions. Customary (Maori) harvest is controlled by way of area-specific regulations that can differ from those applying to commercial and recreational users.

36.2.2

Australia

Details of management regimes for Australian rock lobsters are discussed in Chapter 1. The dominant species is P. cygnus, with a sustainable catch of 10 800 t p.a. and an upward trend in recruitment (Anon., 1998a). The annual catch of J. edwardsii is 4500 t with small catches of other species. Management, while primarily for biological sustainability, increasingly takes marketing into consideration in its decisions (Anon. 1998b). In Western Australia, where the catch may be predicted up to 4 years in advance, moves to transfer production from seasons of heavy recruitment to those of lower catches have been

Export Marketing of Australian and New Zealand Spiny Lobsters

643

implemented. In all states, the non-commercial catch is also subject to controls such as licenses and bag limits. Both the south-eastern zone of South Australia (1993/94) and Tasmania (1998/99) have introduced output controls (quotas) in addition to input controls, relaxing seasonal closures to allow fishermen to take advantage of the fact that the dominant Western Australian production occurs during 15 November to 30 June. Annual harvest (by state for Australia) for 1992-98 is given in Table 36.1.

36.3

Commercial structure

All of the major fisheries use pots or traps, many of which are restricted in their design, and (in Western Australia) include escape gaps to allow undersized lobster to escape (Fish Resources Management Act 1994 and Fish Resources Management Regulations 1995). Tropical rock lobster are still typically caught by spear or, increasingly, by hand, while the Queensland catch is mainly a byproduct from fish and prawn trawling. Most fishing vessels are independently owned and operated, however, in New Zealand there has been a noticeable control of the harvesting opportunity by processing and marketing companies since the introduction of rock lobster to the quota management system (QMS) in 1990. Quota trade prices have generally increased over time, although there have been fluctuations in the southern regions. The reluctance of banks and lending institutions to accept quota as a mortgageable Table 36.1 Annual harvest (t, July-June) of Australian and New Zealand rock lobsters by state

State

1992/93 1993/94 1994/95 1995/96 1996/97 1997/98 1998/99 Total

NSW Victoria Queensland WA SA Tasmania NT C'wealth" Total

100 439 585 12 366 2818 1907

~~

~~

143 524 546 11 045 2629 1907

-

174 18 389

185 16 979

84 509 607 10 886 261 1 1387

103 483 723 9902 2587 1786

104 458 582 9979 2528 1819

107 508 66 1 10 485 2622 1485

110 47 1 550 13 063 2729 1353

-

-

-

-

-

182 16 266

20 1 15 785

233 15 703

219 16 087

50 1 18 777

751 3392 4254 77 726 18 524 11 644 0 1695 117 986

Source: ABARE, Australian Fisheries Statistics, Canberra. 'Commonwealth production is from the Torres Straights Islands. (The Rock Lobster fishery is under Commonwealth and State (QLD) joint jurisdiction.) NSW, New South Wales; WA, Western Australia; SA, South Australia; NT, Northern Territory.

644 Spiny Lobsters: Fisheries and Culture

security has made it difficult for existing fishermen or new entrants to increase their quota ownership (Table 36.2). New Zealand processing companies have actively sought to increase quota ownership in order to ensure supply for export, and are able to gain significant leverage of product by making quota available for lease to fishermen. The level of corporate ownership vanes in New Zealand. In some regions the numbers of quota-owning operator fishermen has remained relatively stable since 1990, but in others there is a high incidence of full or partial lease dependency. Fisheries legislation provides for a 10% aggregation limit on quota ownership, but exemptions are routinely granted. Legislation prevents a quota being sold to or owned by an overseas individual or a New Zealand company with greater than 25% overseas control. Records of pot and/or quota values in Australia are not kept. There is evidence for similar increases in values in each of the major states. In Tasmania the price of each of the 10 5 14 pots in the fishery has increased from Aus $4000 in 1994 to Aus $1 8 000 in 1999 (R. Treloggen, pers.comm.). In the Victorian eastern zone the increase is rather lower, from Aus $1600 to Aus $2600 per pot for 2600 pots over the same period, and in the Victorian western zone from Aus $5000 to Aus $7500 per pot for each of the 5388 pots in that fishery over the same period (K. Saunders, pers. comm.). For the South Australian northern zone pots averaged Aus $19 000 each on transfer in 1994, rising to Aus $26 400 in 1999. The south-eastern zone of the fishery was steadier, with values increasing from Aus $17 800 each to Aus $20 500 each in those years. For both zones the rate of increase slowed after some spectacular gains in previous years. In 1987 the values were just Aus $4100 and Aus $2500, respectively (R. Edwards, pers comm.).

Table 36.2 Average quota trade and lease prices/t (NZ $) Trade

Lease

Region

Oct 90-Sept 91

Oct 97-Sept 98

Oct 90-Sept 91

Oct 97-Sept 98

CRA 1 CRA 2 CRA 3 CRA 4 CRA 5 CRA 6 CRA 7 CRA 8 CRA 9

41 032 23 706 31 540 25 041 23 265 19 500 29 624 25 192 38 372

172 143 215 444 171 275 203 667 222 500 77 646 47 002 82 120 165 000

5979 6465 4333 6499 3186 2813 7160 3992 3985

15 988 17 487 16 193 18 082 12 325 4562 3873 6562 16 564

~~

Aus $1

=

NZ $1.3.

~

~

Export Marketing of Australian and New Zealand Spiny Lobsters

645

For Western Australia the increase in pot values has been accelerated by successive reductions in pot numbers. A permanent 10% reduction over 5 years from 1988 to 1993 was matched by a per pot price increase from Aus $5000 to Aus $13 000 for 78 000 pots. With steadily improving landed prices the pot price improved to Aus $33 000 in 1997/98, when it peaked. This was, at least in part, also due to a further 18% temporary pot reduction, reducing the number of usable pots in the fishery to 58 000. The advent of the record 1998/99 and 1999/2000 seasons, coupled with the Asian financial crisis, caused landed prices to fall substantially for the first time since 1987/88,and the price of pots followed. Individual pot prices fell to below Aus $20 000 each, with some evidence of recovery to Aus $24 000 per pot in late 1999. The catch is sold to processors who generally process for export. However, 3840 t (24%) of Australian and approximately 180 t (6%) of New Zealand lobster were sold into the respective domestic markets in 1997/98, with some sales of New Zealand lobster into New South Wales and Victoria. Lobsters are either bought outright with settlement within 7 days, or on consignment with a final price being paid after completion of the transaction or at the end of the season. Many fishermen use both systems, particularly in Western Australia where consignment (or ‘pool’) payments were used extensively when the US market predominated. Lobster are graded by size and weight by processors, and grading systems on purchase (usually listed to small, medium and large) have gained acceptance in both Australia and New Zealand. There is, however, no uniform standard grading system. Buyers will also grade lobster for their fitness for live sale, and strenuous efforts are made by fishermen to take great care of their catch. In both countries differential prices for each grade apply according to export market destination and withinseason export demand. Gross values of production in Australia increased steadily from 1991 to 1998 owing to a number of factors including market diversification, improvements in quality and the depreciation of the Australian dollar against the currencies of major trading partners (Table 36.3). In New Zealand the export values fell during the 3 years to 1998, losing the steady gains made before then. Lobster export values also fell in comparison to other seafood sectors during the period to 1998. The Australian trend was also reversed at the start of the 1998/99 lobster season in Western Australia (November 1998) when the beach price fell to Aus $16/kg, reflecting market changes in Japan and the onset of a very high catch season (Table 36.4.).

36.4

Processing

In both countries fishermen have made great efforts to ensure that all lobster are landed alive and in good condition. (Harvey, 1993; Stevens et al., 1995). Exporters must be licensed, frequently by multiple agencies. In both countries strict hygiene and occupational health and safety regimes are established.

646 Spiny Lobsters: Fisheries and Culture Table 36.3 Gross values of production (landed value) of rock lobster in thousands of Australian dollars from 1992 to 1999 (July-June) 1992/93 1993194 1994/95 1995196 1996/97 1997/98 1998/99 Total 24 785 3778 3938 3820 3666 4179 3102 2302 NSW 97 310 9422 11 635 15 782 14 117 14 550 16 444 15 360 Victoria 44 594 5467 7033 7937 6599 5594 6506 5458 Queensland 228 699 287 122 304 690 225 562 254 614 210 211 261 424 1 772 322 WA 55 338 66 583 74 043 68 399 71 379 78 351 73 908 488 001 SA 41 287 41 287 41 427 47 894 53 330 46 223 39 846 311 294 Tasmania 3 NT 4 7 6231 4969 5264 5500 7223 10 184 7158 46 529 C'wealth Aust. total 347 614 421 532 450 01 1 372 375 411 907 373 288 408 115 2 376 529 790 812 NZ (NZ $1 102 542 117 915 118 093 116 962 113 055 106 582 115 667 Source: ABARE. Figures for New Zealand are FOB values in NZ $. Landed value figures are not kept.

In Australia all exporters require a licence from the Australian Quarantine and Inspection Service (AQIS). AQIS provides certificates of both Origin and Health, and carries out both product and establishment inspection. Many exporters selfassess product via the HACCP-based Australian Quality Assurance (AQA) system, with AQIS or a certified third party auditing the process. In addition, most States Fisheries Agencies license exporters. Western Australia has limited the number of exporter establishments to 19 premises, controlled by 12 companies. All other states have completely deregulated the processing sector (Anon, 1998~). Table 36.4 Average landed price per kilogram for rock lobster in Australian dollars from 1992 to 1998 (July-June) State NSW Victoria Queensland WA SA Tasmania NT C'wealth Average

1992193 1993/94 1994195 1995/96 1996/97 1997198 1998199 Average 23.02 21.46 9.56 18.49 19.64 21.65

29.22 22.20 10.00 26.00 25.33 21.65

36.93 31.01 9.01 27.99 28.36 29.87

35.59 29.23 9.00 22.78 26.44 26.82

36.33 31.77 12.08 25.51 28.24 29.32

36.80 32.37 12.01 20.05 29.88 31.13

34.73 32.61 12.00 20.01 27.08 29.45

33.23 28.66 10.52 22.97 26.42 22.92

28.56 18.90

28.45 24.83

30.22 27.67

31.00 23.59

31.00 26.23

46.50 23.20

14.29 21.73

30.00 23.73

*

*

*

*

*

*

*

*

Source: ABARE. *Too few to be recorded. Figures for new Zealand are not kept. The landed price tends to equate closely with the figure for South Australia, but in New Zealand dollars (Aus $1 = NZ $1.3).

Export Marketing of Australian and New Zealand Spiny Lobsters

647

In New Zealand the introduction of the QMS in 1986 required all fish processors to register as Licensed Fish Receivers (LFRs). There are 38 LFRs who process > 3 t of rock lobster in any year. Of these, 15 LFRs process > 150 t annually. Rock lobster for export must processed and packed in premises holding Export Fish Packhouse certificates issued by the Ministry of Agriculture (MAFQual). LFRs are subject to self-audit of product flow reported to Ministry of Fisheries Compliance division. MFish Compliance routinely conducts intensive inspection and audit to ensure adherence to the reporting requirements of the QMS. LFRs have strict liability to ensure that lobsters are purchased only from legitimate commercial fishermen and that all lobsters meet regulatory requirements in terms of MLS, condition, hygiene and health and safety issues. The export of rock lobster is deregulated and in addition to lobster processors there is a small number of export brokers and marketers offering their services to the New Zealand industry. The New Zealand Rock Lobster Exporters Association (NZRLEA) membership comprises the majority of long established lobster processing and exporting companies. The New Zealand Seafood Industry Council (SeaFIC) issues fish Export Licences (FELs).

36.5

Pack styles

Lobsters are processed into a number of different forms and pack styles. Live Lobster: lobsters are held alive, typically for 3 days, in flow-through or recirculating seawater holding tanks. This allows the lobster to purge their gut contents, and processors to cull those that will not survive packing and transport. The lobsters are immobilized prior to packing by lowering their body temperature. They are graded and packed in 8-kg, 9-kg or 10-kg net weight cartons, usually with a 1-2% margin to allow for weight loss in transit. Larger lobsters are packed in random-weight cartons. Whole raw lobster (WRL), to be packed as WRL lobster must be alive when entering the process. Lobsters are anaesthetized and suffocated in iced fresh water, graded, wrapped and packed in 10-kg cartons. The cartons are blast frozen to -4O"C, and stored below -25°C. They are shipped in sea containers, or occasionally by air. Whole cooked lobster (WCL): unique to Western Australia, the process is similar to that for WRL, other than the lobster are boiled in heavily salted water for between 8 and 20 min, depending on size, then rapidly chilled and thoroughly washed and drained before wrapping, packing and freezing. WCL are also consigned in chilled form, by air, particularly to France. Lobster tails: the first export product for rock lobster, lobster tails are processed from lobster that are anaesthetized and suffocated in iced fresh water. The head is removed, and the hindgut vacuum extracted. The tails are then thoroughly washed, drained, graded and packed and frozen as above. As tails are consigned

648 Spiny Lobsters: Fisheries and Culture almost exclusively for the US market they are packed in cartons in Imperial weights of 10 lb (4.54 kg) and 25 lb (11.34 kg). Lobster heads: a byproduct from tail production; the heads are not washed or wrapped, but graded and placed in a 10-kg lined carton and frozen. Paste: this is another byproduct from tail production. Lobster heads are finely macerated and the resultant paste is plate-frozen or air-blast-frozen into blocks. Lobsters are delivered by either air or sea freight. Live lobsters are routinely airfreighted, and will survive comfortably for up to 30 h with minimal (<5%) mortality. Continuous improvement in packaging and handling has both extended the time in transit and reduced mortalities, to the point where a mortality rate below 1% is unremarkable (Walker et al., 1994). Frozen lobsters are routinely shipped by sea in standard (20- and 40-foot) sea containers. Chilled lobsters are airfreighted, as is frozen product when the market demands rapid delivery. In both countries strict hygiene and occupational health and safety regimes are established.

36.6

Markets

The chief markets for Australasian spiny lobster are Japan, Taiwan, the Hong Kong Special Administrative Region (SAR) and the People’s Republic of China (PRC), and the USA. The return of Hong Kong to China has enhanced rather than disrupted the flow of product through the SAR into China, although difficulties remain in gaining unrestricted access to the PRC. Exporters from both countries have also experienced difficulties with currency transfers and the system of import duties and local taxes in the Chinese market. The Japanese market softened from 1997, with the effects of recession and remained depressed into 1999, although some recovery became apparent late in the year. The Taiwanese market remained steady, while the US market improved after a long decline. Stricter policing of import tariffs by Taiwan had a noticeable effect on the volume of New Zealand lobster exports to that country. Singapore is a significant market for southern rock lobster. A concerted effort to improve sales in Europe started in 1998, despite the imposition of both tariff and non-tariff trade barriers by the European Union (EU). Sales of western rock lobster in Europe increased by 90% in 1999 over 1998 (Anon., 1996, 1997; McLeod, 1996; Cicerello, 1998). The volumes of product shipped to each country are given in Tables 36.5 a and b. The long decline in production of tails for the US market slowed as the effects of the Asian economic downturn began to affect lobster sales within APEC countries, and was actually reversed in the 1997/98 season. Production of tails, particularly from Western Australia, continued to firm in 1998/99. The US accounted for 8.1%

Export Marketing of Australian and New Zealand Spiny Lobsters Table 36.5

649

(a) Australian exports of rock lobster by destination 1996197 Wt (t)

Whole Live fresh or chilled China Chinese Taipei Hong Kong Japan Singapore USA Other Total Frozen raw China Chinese Taipei Hong Kong Japan Singapore USA Other Total Frozen cooked China Chinese Taipei Japan Singapore Other Total Tails Fresh, chilled or frozen China Chinese Taipei Hong Kong Japan Singapore USA Other Total Source: ABARE.

Value (Aus tS'000)

1997/98 Wt (t)

Value (Aus $'OOO)

1998/99 Wt (t)

Value (Aus $'OOO)

806 2163 2637 1377 75 20 52 7130

30 741 78 144 101 536 51 319 2923 710 1925 267 298

1896 1410 2173 1655 62 15 44 7255

75 223 41 668 81 672 51 202 2402 593 1504 254 265

1520 1680 3185 1770 43 44 132 8374

0 200 43 374 9 17 21 407 1

1 6035 804 11 159 236 1128 323 19 686

0 196 18 415 0 3 1 632

0 5299 501 11 217 2 119 21 17 213

5

111

161 5 415 19 91 18 714

4254 103 8950 466 2713 407 17 004

1 1739 1674 20 94 3528

34 53 244 55 272 54 1 3109 112 220

22 2080 949 41 110 3202

583 56 863 25 929 1222 3134 87 731

89 2169 1142 150 113 3663

204 1 49 681 28 144 3725 3365 86 956

0 84 31 I73 6 668 10 972

6 2375 1358 7409 235 37 467 593 49 443

1 8 25 48 1 963 3 1049

26 260 1209 3230 58 58 956 69 63 808

0 72 68 182 12 1113 17 1464

0 1770 1542 683 I 499 63 773 648 75 063

54 188 47 735 106 178 52 778 1569 2131 3978 268 557

650 Spiny Lobsters: Fisheries and Culture Table 36.5 (b) New Zealand exports of rock lobster by destination

1997 Wt (t) Whole Live fresh or chilled China Chinese Taipei Hong Kong Japan Singapore USA Other Total

404 493 1039 737 38 2 93 2805

Value (NZ $'OOO)

16.0 17.6 39.5 27.5 1.7 0.1 3.7 106.0

1998 Wt (t)

844 189 923 61 1 39 2 94 2702

Value (NZ $'OOO)

31.5 6.2 31.5 20.8 1.5 0.1 3.3 94.8

1999 Wt (t)

39 340 1767 554 24 4 37 2766

Value (NZ $'OOO)

1.1 12.8 67.2 22.8 1 .o 0.1 1.4 106.3

86% of NZ lobsters are exported live, 9% as WRL, 5% as tails and 0.1% as WCL.

by volume, and 13.9% by value of Australian exports, with 99.1% of the production in the form of tails. The Japanese market for small whole cooked lobster suffered from the economic malaise affecting that country to a greater extent than that for live lobster. Whole cooked lobsters are chiefly used for wedding celebrations, a market that has borne the brunt of the fall in demand. In 1997/98 Japan received 25.4% by volume, and 21.8% by value of the combined exports from the Australian states. There was evidence for a recovery in the Japanese market late in 1999, with exports of whole cooked lobster from Western Australia improving by 17% over the previous year (A.P. Gibson, pers. comm.). Taiwan overtook Japan as the major export market in 1996/97 and lost that position only when China incorporated Hong Kong. Taiwan imported the 30.4% by volume and 24.6% by value of Australian exports in 1997/98. Taiwan is the largest market for frozen whole cooked lobster. With the incorporation of Hong Kong into China, some of the administrative difficulties faced by spiny lobster exporters were alleviated. Hong Kong remains a major port of entry to China, although Shanghai, Guangdong Dahlien and Beijing are becoming significant entry ports. Over 34.6% by volume and 38.2% by value of Australian lobsters are shipped to China. The majority (4078 t) of shipments to China was in live form, with the greatest demand being for larger (2800 g) sizes. Singapore and other Asian countries, and the EU absorb the remaining 1.5% (1.4% by value) of export production.

Export Marketing of Australian and New Zealand Spiny Lobsters 36.7

651

Live lobster exports

The markets for processed lobster have been relatively few, and unchanged since the entry of Taiwan as a major lobster importer. The number of markets for live lobster is both large and growing. While the combined live lobster exports have stabilized, after a period of rapid expansion, at about 10 000 t p.a., exports to major markets have declined slightly as a more diverse market base has been sought (Figs 36. la, b). Live lobsters may be traded in small consignments, allowing their sale to niche markets. The diversity of importing countries is shown in Table 36.5. New Zealand exporters also take advantage of seasonal supply to exploit the same markets as Australia, during the months of low Australian supply (Fig. 36.1~).

36.8

Future markets and constraints to trade

The industry has made a concerted effort since 1997 to gain access to the EU market. Early data from the 1998/99 season suggest that exports from Western Australia alone exceeded the exports from both countries combined during the previous year (A P Gibson, pers. comm.). Exports from Australia to the UK increased by 90% in 1998, albeit from a very low base (Table 36.6). Active promotion in European markets is combined with strenuous efforts to have the 15% tariff on Australian and New Zealand lobster reduced or removed. Both countries are severely disadvantaged compared with major competitors such as Table 36.6 UK Imports of spiny and homarid lobster 1998 and Jan-Mar 1999 Jan-Feb 1999

1998

Description ~

Country ~~

Rock lobsters and other crawfish

Total Lobsters (Homarus spp)

Total ~

Source: H.M. Customs and Excise.

Wt (t)

Value (f’000)

~~

Nicaragua Australia Oman Others Canada USA BelgiumLuxembourg Others

Wt (t) ~

21 23 17 11 50 910 296 15

40 1 20 1 136 140 471 6031 2032 I22

32 1274

275 8862

Value (E’000) ~~

15 2

265 20

5 22 202 29

81 367 1534 23 1

4 236

66 1830

652 Spiny Lobsters: Fisheries and Culture

Fig. 36.1 (a) Australia live and chilled spiny lobster exports; (b) Australian live and chilled spiny lobster exports by ‘other’ destinations; (c) Australian and New Zealand live and chilled spiny lobster exports.

Export Marketing of Australian and New Zealand Spiny Lobsters

653

Canada (4% tariff) and Cuba (0% tariff) (Cicerello 1998). It is expected that the countries will continue to diversify their marketing efforts. Markets for live and chilled lobster in particular have great growth potential. Those listed in Fig. 36.lb have been aggregated by region, but within Europe alone, and despite tariff barriers, there has been significant effort into countries such as Italy, Switzerland, the Benelux countries and Germany. Australian and New Zealand exporters have expanded their presence at the European Seafood Exposition in Brussels each year since 1998. Attempts continue to sell product to the Middle Eastern countries, despite competition from Oman, and to North America, despite strong competition from a range of countries, particularly Brazil and the Caribbean. The production and marketing of spiny lobster from Australasia is considered to be both very stable and very robust. The trade has survived the vagaries of both market and currency variations, and will continue to be a strong competitor in the international market for spiny lobster.

References Anon. (1996) Analysis of the global rock lobster market. The Marketing Centre Pty. Ltd, Perth, Western Australia. Anon. (1997) market investigation into the generic promotion of the Western Rock Lobster in key Asian markets. The Marketing Centre Pty. Ltd, Perth, Western Australia. Anon. (1998a) The effects of five years (1993/94 to 1997/98) of stable management in the Western Rock Lobster fishery. Commercial Fish. Res. Bull., Fisheries WA. Anon (1998b) Future directions for the Rock Lobster Industry Advisory Committee and the Western Rock Lobster managed fishery. Fish. Manage. Paper, No. 123, Fisheries WA. Anon. (1998~)Special Report: The Western Australian lobster fishery. PPB Ashton Read, Perth, Western Australia. Cicerello, E. (1998) A review of the core markets and competitors of the Western Australian Rock Lobster industry. The Rock Lobster Industry Advisory Committee, Perth, Western Australia. Harvey, R. (1993) A Code of Practice for Rock Lobster Products. New Zealand Fishing Industry Board, Wellington, New Zealand. McLeod, R. (1996) Market Access Issues for the New Zealand Seafood Trade. New Zealand Fishing Industry Board, Wellington, New Zealand. Stevens, R.N., Turner, D. & Whissen, G. (1995) Fifteen Minutes, A Code of Practice for Handling Live Rock Lobster. WA Fishing Industry Council, Perth, Western Australia. Walker, M.H., Walsh, P.B., Gibson, A.P. & Roe, J.A. (1994) An improved packaging system for live Western Rock Lobster. Report, National Seafood Centre, Hamilton, Queensland, Australia.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 37

Marketing and Distribution in Japan M.TSURUTA

Clean Bio Consulting Co. Lid., Shiroi-cho 438, Inba-gun, Chiba-ken, Japan

J. KITTAKA Research Institute for Marine Biological Science. Research Institutes for Science and Technology, The Science University of Tokyo, Nemuro City. Fisheries Research Institute. Hokkaido. 087-0166, Japan

37.1

Introduction

The Japanese appreciate shrimp, prawn and spiny lobster very much because of the good taste and beautiful red colour after cooking. In particular, the Japanese spiny lobster Punulirus juponicus has become a symbolic decoration on New Year’s Day, and the main and indispensable dish at wedding ceremonies because of its red appearance and with a pair of long antenna which symbolizes happiness and longevity. The lobsters’ habitat is limited to the rocky coast washed by the warm current Kuroshio. The Japanese have given this lobster the highest value in marine products because of its scarcity. The high level of economic growth since 1960s has brought an excess of imports over exports in fisheries products of Japan. This tendency originated in the strong demand for seafood associated with the recent socioeconomic trends: (1) continuance of the high yen value; (2) liberalization of trade as established by the Uruguay Round; and (3) withdrawal from offshore fisheries owing to the establishment of the 200 nautical mile epoch. Domestic fisheries production in Japan (both fisheries and aquaculture) showed a decreasing tendency from 12 171 000 t in 1985 to 7 41 1 000 t in 1997, while the total amount of imports of fisheries products during the same period increased from 1 577 000 t to 3 411 000 t, with a peak at 3 582 000 t in 1995 (Nourin Toukei Kyoukai, 1999). It is apparent that the decrease in domestic production is covered by the increase of imports. This tendency will continue in the future. Among the various imported items, shrimp, prawn and lobster ranked first in quantity (192 000 t in 1985 and 282 000 t in 1997, with a peak at 320 000 t in 1995) (Nourin Toukei Kyoukai, 1999). However, there has been a slight decreasing tendency in the consumption of shrimp, prawn and lobster since 1995, perhaps associated with the recent economic recession in Japan. In this chapter, systems and mechanisms in the marketing and distribution of spiny lobster are viewed for both domestic and imported products, and future marketing strategies for spiny lobster are discussed. 654

Marketing and Distribution in Japan 37.2

655

Production and consumption of spiny lobsters in Japan

Seven species of the genus Panulirus are distributed along the south-east coasts of the Japanese Archipelago (Saisho, 1988). Among them, P . japonicus is the most abundant and highly appreciated. Many species of this genus occur in the tropical and subtropical areas and are exported as frozen products to the consuming countries. In contrast, the species of the genus Jasus occurs in the cool-temperate waters of the Southern Ocean (George & Main, 1967). They are shipped as frozen and live, fresh or chilled products (Oshikata, 1994).Jasus species are preferred in Japan because of their red colour and good taste, which are comparable to P. japonicus.

37.2.1

Domestic production in Japan

The main producing areas are Nagasaki, Kagoshima, Wakayama, Mie, Shizuoka and Chiba Prefectures, and Tokyo Metropolitan (offshore islands) with Kuroshio (Nonaka, 1996).The spiny lobster resource has been well managed by fishermen and fisheries co-operatives. The annual total quantity of catch fluctuated between 969 t in 1988 and 1574 t in 1965, with an average 1174 t excluding the lowest catch at 236 t in 1945 due to World War I1 (see the Annual Report for Production Statistics in Fisheries and Aquaculture by the Ministry of Agriculture, Forestry and Fisheries). This average quantity is roughly equivalent to 6 000 000 spiny lobster of 200 g size. This implies that number of harvested spiny lobsters has definitely been insufficient to supply the population of 100 000 000 in Japan. It is apparent that the local supply cannot till the demand in Japan. Shortage of production caused, first, the development of larval culture technology and, secondly, the increase in imports of live spiny lobsters.

37.2.2

Imports from overseas

Frozen spiny lobsters and live, fresh and chilled spiny lobsters are imported by major general trading firms (called Sohgoh shosha), medium-scale importers and major fishery companies (Nakai, 1984; Oshikata, 1994). Live, fresh and chilled spiny lobster are imported by specialized medium and small firms (Oshikata, 1994), which have had experience in live fish marketing and distribution outside the wholesale market (see following paragraph). Their knowledge acquired in the live fish business was useful for rapid and timely distribution to the consumers. Total quantities and average prices of live, fresh and chilled lobsters imported into Japan in 1991 (Oshikata, 1994) and 1998 (Japan Tariff Association, 1999) are shown in Table 37.1. The average price of lobster imported from Norway, Canada and the USA was apparently lower than that of the imports from other countries. There was some

656 Spiny Lobsters: Fisheries and Culture Table 37.1 Quantity and average price of imported live, fresh or chilled spiny lobsters in 1991 and 1998

Country Taiwan Hong Kong Singapore Phillipines Indonesia Norway Canada USA Costa Rica Cuba Angola South Africa Australia New Zealand Other Total (kg) Average (yen/kg)

1991

1998

Quantity (kg)

Price (yen/kg)

Quantity (kg)

Price (yen/kg)

9217 717 1078 3827 8778 0 400 8606 170 360 0 11 507 1 168 611 1 189 116 960 2 403 347

5673 2454 333 1 3346 2978

8648 0 0 0 9372 638 2504 23 507 0 0 546 226 190 1581 214 517 271 0 2 369 890

6202

3800 2626 3029 3330 3088 3965 3998 3700 3973

3388 650 1967 2251 2863 2756 2908 3416 3010

Source: Oshikata (1994); Japan Tariff Association (1999).

doubt that the lobsters imported from these countries were not species of spiny lobster but other species such as Nephrops and Homarus. Imports from the countries in the southern hemisphere were considered to be Jasus lalandii from South Africa, J . edwardsii from New Zealand, and both J. edwardsii and Panulirus cygnus from Australia. Imports from these countries in 1991 and 1998 were kept at the same level at around 2300 t, but the average price decreased from 3600 yen/kg in 1991 to 3000 yenlkg in 1998 (Oshikata, 1994; Japan Tariff Association, 1999). The total quantity and average price of frozen lobster imported into Japan in 1991 and 1998 are shown in Table 37.2. The decrease in the import of frozen lobsters is clearly shown: 12 337 t in 1991 decreased to 7056 t in 1998, with a decreasing rate of 43%. Frozen lobsters were imported from 33 countries in 1991, while decreasing to 21 countries in 1998. The average price of the frozen lobster was 2670 yenlkg in 199 1, decreasing to 1934 yen/ kg in 1998, with a rate of decrease of 28% (Oshikata, 1996; Japan Tariff Association, 1999). The quantity, value and average price of the imported lobster (spiny lobster) in Japan in 1991 and during the period from 1994 to 1998 are shown in Figs. 37.1, 37.2 and 37.3, respectively.

Marketing and Distribution in Japan

651

Table 37.2 Quantity and average price of imported frozen spiny lobsters in 1991 and 1998

Country Taiwan Vietnam Thailand Singapore Philippines Indonesia India Pakistan Sri Lanka Bangladesh Oman U. Arab E. France Bulgaria Canada USA Mexico Honduras Belize Costa Rica Panama Cuba Haiti Columbia Brazil Chile St. Helena Seychelles Mozambique Madagascar Namibia South Africa Australia New Zealand Solomon Is. Total (kg) Average (yen/kg)

1991

1998

Quantity (kg)

Price (yen/kg)

120 270 171 4368 474 242 837 332 261 1 382 518 231 124 153 038 120 65 792 0 296 240 4010 179 668 682 621 63 500 5805 1216 306 113 310 1 737 450 1620 11 739 1 033 810 0 182 820 12 120 167 412 188 250 353 732 1 502 694 2 960 525 193 167 2757 12 377 595

3116 2207 2617 2299 2175 2239 228 1 2262 2677 1691 2303 2963 1092 1356 2186 2378 3910 2747 2349 2995 2454 2279 1576 3005 3253 301 1 2584 2535 3139 2534 3140 3312 2172 2670

Quantity (kg)

Price (yen/kg)

0 0 0

0 35 132 502 626 714 635 72 670 13 020 0 2300 7899 273 810 0 140 291 246 153 9525 0 0 0 23 550 1710010 0 0 68 346 10 000 155 857 0 73 919 149 690 228 600 955 077 1 551 417 12 050 0 7 056 577

1682 1492 1268 1036 1690 1281 2758 2154 2752 1921 2065

1481 1903 2870 1981 1654 1747 2295 2067 2224 2802 1934

Source: Oshikata (1994); Japan Tariff Association (1999).

In general, the quantity, value and average price of the imported lobsters showed a decreasing tendency for frozen lobsters, while they were rather stable for live, fresh and chilled lobsters.

658 Spiny Lobsters: Fisheries and Culture

Fig. 37.1 Quantity of imported spiny lobsters in Japan in 1991 and during the period from 1994 to 1998. Source: Japan Tariff Association (1999).

Fig. 37.2 Value of imported spiny lobsters in Japan in 1991 and during the period from 1994 to 1998. Source: Oshikata (1994), Japan Tariff Association (1995, 1996, 1997, 1998, 1999).

37.3

Marketing and distribution system in Japan

In Japan, public markets were opened nation-wide by the Central Wholesale Market Law in 1918. Tsukiji Market is one of 11 Central Wholesale Market established by Tokyo Metropolitan Government in 1935 and well-known for handling a huge amount of fish and shellfish. The market dates back to the 1600s. The Tokugawa Shogunate brought the fishermen in the Osaka area to Edo (presently Tokyo) to let them catch and sell seafoods at a site near Tsukiji. After the Meiji Restoration, the market was managed

Marketing and Distribution in Japan

659

Fig. 37.3 Average price of imported spiny lobsters in Japan in 1991 and during the period from 1994 to 1998. Source: Japan Tariff Association (1995, 1996, 1997, 1998, 1999).

as a private establishment under the permission of the new Tokyo City Government. However, because of the social unrest attributable to a rice shortage in 1918, the Central Wholesale Sale Market Law was enacted in 1923. In the same year, the Great Kanto Earthquake completely destroyed Tokyo City. The new construction of a wholesale market at Tsukiji was completed in 1935 (see the Market Guide, a leaflet issued by Tokyo Metropolitan Central Wholesale Market). The wholesale markets have played an important role in collecting and distributing various kinds of food from producers to consumers. Their function in fair price determination and hygiene checks and inspection will be more important in the epoch of trade liberation. However, the increasing imports of new food items has developed another channel for marketing and distribution which does not necessarily pass through the central wholesale markets.

37.3.1

Marketing and distribution through central wholesale markets

Most fish and shellfish are collected in wholesale markets in producing areas, and shipped to central wholesale markets in consuming areas by purchase brokers. The wholesalers sell the goods to intermediate wholesalers and authorized buyers. In the case of spiny lobsters, the live lobsters, packed in a polystyrene box with sawdust and a coolant, were shipped from the producing area to the markets before the time of the auction. The price of spiny lobster, like other fishery products, is determined by auction at the market. The vitality, colour and size of the lobsters affect the auction price, which is associated with the daily balance between supply and demand.

660 Spiny Lobsters: Fisheries and Culture

The intermediate wholesalers sell goods in small numbers at their own shop to stock purchasers. The authorized buyers, comprised of the retailers and supermarket agents, may purchase at auction if they obtain permission from the establishment authority. Such a distribution system seems to be complicated; however, fair price determination and the rapid distribution of goods are advantageous for consumers.

37.3.2

Marketing and distribution outside wholesale markets

In general, the wholesalers in the central market are unfamiliar with handling live marine fish. In addition, facilities in the central wholesale market do not have sufficient numbers of the holding tanks to keep live fish before and after the auction. Even if there were the holding tanks, inspection of live individuals prior to auction would be difficult. However, demand for live marine fish has been more popular with consumers. This has developed the distribution channel outside the market. Imports of frozen prawns in Japan have increased since the 1970s. About 70% of imported frozen prawns has passed through the system outside the market, 20% through the wholesalers in the central market and 10% supplied directly to the frozen food processers. Frozen prawn is well-standardized by species, size and quality, therefore, the price can be determined without inspection and auction. Imported frozen lobsters have been handled through similar marketing channels (Nakai, 1984).

37.4 37.4.1

Marketing and distribution of imported spiny lobsters Live spiny lobsters

Imported materials are received by the importers after customs clearance and quarantine. Importers bring back the cartons to their facilities and keep the spiny lobsters in holding tanks until secondary shipping (Oshikata, 1994). At the beginning of importation, mortality was high owing to inexperience and inadequate handling before and during shipment. Because of mortality, it was necessary to separate live and dead lobsters. Such troublesome work is not suitable for the business of largescale companies. Domestic live fish dealers, with their long-term experience, have had an important role in imports of the cool-temperate species. Live spiny lobsters are transported by air. The total value of imported seafood at Narita (Tokyo) Airport was about 140 000 000 000 yen in 1994. This value was 2.4 times that of landed at Yaizu Fishing Port (Shizuoka Prefecture; the landed value of the year was the highest in Japan) (Kurihara, 1997). Several importers have used the holding tanks near Narita Fishing Port. About 250-300 individuals are kept in a unit holding tank (dimensions: 2.5 x 2.5 x 0.5 m deep; capacity 3 t). The tank water is recirculated at a rate of 6 9 t/day through a filter system. The spiny lobsters are

Marketing and Distribution in Japan

661

shipped mainly to the central wholesale markets, restaurants, supermarkets, etc., and partly to the consumers by express delivery service within 3-4 days after arrival.

37.4.2

Frozen spiny lobsters

Frozen spiny lobsters are imported by general trading firms, major fishery companies and primary wholesale firms. These importers wholesale the goods to the primary wholesalers outside the market (about 70%), the central wholesale markets (about 20%) and to frozen food processing companies (about 10%). The wholesalers deliver the goods directly or as processed food (from the half-cut to the ready-to-broil) by the food processors to the department stores. Thus, the frozen lobsters pass through a complicated channel to food service industries, restaurants, department stores, supermarkets, retail outlets, etc. (Nakai, 1984). The marketing channel for frozen spiny lobsters has not changed; however, the economic situation has changed remarkably in Japan. Spiny lobsters were dealt with in a seller’s market for several years, but they are now traded in a buyer’s market associated with the decrease of demand owing to the collapse of the economy.

31.4.3

Marketing trend at the Tsukiji Central Wholesale Market

The Tsukiji Market supplies seafood to the residents of Tokyo. The species, quantity and price handled in the market are mainly influenced by the preferences of Tokyo residents. It is believed that the trend in Tsukiji Market is representative of the tendency of consumption in Japan. The handling quantities and average price of the live and frozen spiny lobsters during the period from 1994 to 1998 (Tokyo Central Wholesale Market, 1999) are shown in Figs. 37.4 and 37.5. The quantity of live spiny lobster of both domestic and imported products was relatively stable compared with the frozen products. However, the imported frozen products in 1998 decreased to about 40% of the 1994 value. The average price of the imported frozen products also decreased to about 80% of the 1994 value. These tendencies are the present trend in the importation and marketing of spiny lobsters in Japan (see Figs. 37.1 and 37.3).

37.5

Future perspectives

It is apparent that the domestic consumption of spiny lobster in Japan has decreased owing to the economic depression. The Japanese customarily serve spiny lobster at congratulatory occasions such as weddings and New Year’s Day celebrations. At present, the wedding dinner is served in a simple manner and the traditional

662 Spiny Lobsters: Fisheries and Culture

Fig. 37.4 Handling quantity of spiny lobster at Tsukiji Wholesale Market during the period from 1994 to 1998. Source: Tokyo Central Wholesale Market (1999).

5

/

4i

1994

1996

1996

+Live(domestic)

1997

1998

Prozen(domestic) +Livebported) +FrozenCiported) +-

Fig. 37.5 Average price of spiny lobster at Tsukiji Wholesale Market during the period from 1994 to 1998. Source: Tokyo Central Wholesale Market (1999).

celebrations are often modified to less formal ones. This has led to the decrease in imports of frozen spiny lobsters. However, the quantity of imported live spiny lobsters has been maintained approximately at the same level as before. Fundamentally, the demand for live spiny lobster will continue because the gourmet trend for seafood has not declined, even during the economic depression in Japan. It is necessary to maintain a moderate supply with reasonable price from overseas. Consumption will increase further if a variety of menus can be introduced in Western, Chinese and Japanese dishes; for example, a raw fish (sashimi) dish of the spiny lobster in combination with popular species such as red sea bream and yellowtail. The disadvantage of the spiny lobster as a foodstuff is the relatively large unit size for the consumer. From a nutrition viewpoint, it is wise to take several kinds of seafood in combination in a dish. The high price of the live spiny lobster would be averaged with the lower price of other popular species.

Marketing and Distribution in Japan

663

Usually, spiny lobsters inhabit the coasts washed with clear open seawater. Compared with other seafood, they have less risk of contamination with various toxic substances. Nevertheless, very few producers and suppliers have made efforts to promote spiny lobsters caught in their home ocean as a healthy and safe seafood. Aquaculture production of spiny lobsters will have a great potential for marketing if it can be realized. Although the present market view seems to be rather pessimistic, aquaculture production should not compete with the wild catch; rather, it has stimulated the demand, as has been shown by the success of prawn aquaculture.

References George, R.W. & Main, A.R. (1967) The evolution of spiny lobsters (Palinuridae): a study of evolution in the marine environment. Evolution, 21, 803-20. Japan Tariff Association (1995) Japan Exports & Imports Commodity by Country '94.12 Imports, Tokyo, Japan, 902 pp. Japan Tariff Association (1996) Japan Exports & Imports Commodity by Country '95.12 Imports, Tokyo, Japan, 956 pp. Japan Tariff Association (1997) Japan Exports & Imports Commodity by Country '96.12 Imports, Tokyo, Japan, lo05 pp. Japan Tariff Association (1998) Japan Exports & Imports Commodity by Country '97.12 Imports, Tokyo, Japan, 1019 pp. Japan Tariff Association (1999) Japan Exports & Imports Commodity by Country '98.12 Imports, Tokyo, Japan, 906 pp. Kurihara, K. (1997) May Fish Disappear in the Sea of the World? New Epoch for Fisheries. Norin Toukei Kyoukai, Tokyo, Japan, 21 1 pp. (in Japanese). Nakai, A. (1984) Consumption and marketing of shrimp, prawn and lobster. In Shrimp, Prawn and Lobster in Japan and in the World (Ed. by Editorial Committee for Ninth Extension Lectures at Tokyo University of Fisheries), pp. 221-41. Seizando, Tokyo, Japan (in Japanese). Nonaka, M. (1996) Aquaculture with particular emphasis on Ise lobster. In Aquaculture of Prawn, Lobster and Crab (Ed. by J. Kittaka, F. Takashima & A. Kanazawa), pp. 204-25, KouseishaKouseikaku, Tokyo, Japan (in Japanese). Nourin Toukei Kyoukai (Association for Statistics of Agriculture and Forestry) (1999) An Illustration. A White Paper on Fisheries for the Year of 1998, 284 pp. with an explanation on measures to apply for the coastal fisheries in 1998, 66 pp., Tokyo, Japan (in Japanese). Oshikata, Y.(1994) Marketing and distribution in Japan. In Spiny Lobster Management (Ed. by B.F. Phillips, J.S. Cobb & J. Kittaka), pp. 517-25. Fishing News Books, Blackwell Scientific Publications, Oxford, UK. Saisho, T. (1988) Distribution and life history of Japanese spiny lobsters. In Foodstuj'Js and Bioscience (Ed. by the organizing committee for the Second Symposium on University and Science), pp. 125-34. Asahi Shuppan Sha, Tokyo, Japan (in Japanese). Tokyo Central Wholesale Market (1999) Annual Report of The Tokyo Wholesale Market in 1998 (Part: Marine Products), Tokyo Metropolitan Government, Tokyo, Japan, 495 pp.

Part 4 Perspectives

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Chapter 38

Perspectives B.F. PHILLIPS

Curtin University of Technology, P.O. Box U1987. Perth, Western

Australia 6845, Australia

The many species of spiny lobsters are widespread, found in all tropical and subtropical seas of the world. They are usually the largest decapod present in their habitat and often the largest predator. Before fishing began, they were numerous; even now despite heavy fishing pressure, the smaller size classes are abundant. Their distribution, size and numbers make them ecologically consequential in many communities. These, along with their hardiness and relative ease of handling, have long made spiny lobster an attractive animal to study for marine biologists. However, during the 1980s and 1990s, an increased urgency has been attached to the study of spiny lobsters, as a result of their high commercial value. Flash freezing, air shipment and, most recently, live transport, have opened markets in wealthier nations and tourist locations around the world. In a number of countries, the spiny lobster is very important to the economy. For instance, in Australia, Panulirus cygnus is the most valuable fishery, and makes up in the order of 25% of the country’s entire fisheries export income. In Cuba, lobster exports are one of the major sources for foreign revenue. In this book, we have tried to bring together an overview of the fisheries for spiny lobsters in a number of the producing nations, some of the recent research that bears directly on fisheries management, and information about the newest attempt at increasing the supply of spiny lobsters to the world market - aquaculture. Fisheries trends were reviewed for a variety of nations in the first section of this book. It is clear that significant advances have been made in the last couple of decades. Fishing is more efficient, and fishery biologists have considerably better ability to follow, and even predict in some cases, the trends of catches. In recent years, the catch trends have either been stable or downwards in almost all fisheries. No new grounds have been discovered, nor have new species been exploited, This suggests that the world-wide expansion of the spiny lobster fisheries, begun in the 1950s, came to an end in the 1980s, and we are now in an era requiring attention to the sustainability of the fisheries in the face of high value and high demand. What lessons can be extracted from the experiences recounted in the fisheries status chapters? The fisheries range in type from the industrial, highly capitalized efforts in countries such as Australia and New Zealand to the artisanal, carried out by nets, wading or diving in most of the tropical Pacific islands. The most highly capitalized fisheries tend to be where lobster abundance is highest, coincidentally, largely in developed countries. In contrast, much of the tropical Pacific and western Indian Oceans have a lower abundance of lobsters and fisheries with low capitalization. 667

668 Spiny Lobsters: Fisheries and Culture Nevertheless, with few exceptions, the lobster stocks are exploited at or above sustainable levels. In most of the artisanal fisheries, management efforts are small, and largely limited to gathering catch (and sometimes effort) data, and to regulations on size and gear, In many places regulations are poorly enforced. In contrast, the highly capitalized fisheries tend to have sophisticated data-gathering mechanisms and relatively well-developed knowledge of the biology of the animal. Regulations usually include effort limitations via licences, seasons and, in some cases, total allowable catch. Acceptance of the regulations and enforcement is well established. A number of the authors writing about well-capitalized fisheries emphasized the need to rebuild stocks. It seems that there is not yet clear consensus on how best to regulate highly capitalized fisheries, and that experimentation on this subject continues. Perhaps it is important to recognize the experimental nature of management in these contexts. In general, the approach has been ‘passive adaptive management’ (Walters & Hilborn, 1976) in which incremental changes in regulations are made based on advice generated from historical data. A review (McAllister & Peterman, 1992) advocates a more experimental approach to fisheries management, by applying different regulations in limited areas. Although this is difficult in design and performance, the results could be useful to some of the lobster fisheries. Fishing techniques vary enormously. Tangle nets, spear and hand capture predominate in much of the tropical Pacific, while traps are the rule in highly capitalized fisheries. Despite their higher cost, traps preserve the catch better, and may produce higher revenues. Thus, Munro (Chapter 3) suggests investigations into greater trap use in tropical fisheries where they are not much used now. Traps may also have a smaller environmental impact than other methods such as trammel nets laid on reefs. In Cuba and Mexico, artificial shelters are very effective and appear to produce a higher net benefit than the more costly traps. There is speculation about the ecological effects of the casitas. There is some evidence that they may not only change the distribution of the lobster population (they are installed where shelter did not exist previously) but also increase survival. However, as yet there has been no provision for the removal of damaged or lost casitas, and the ecological consequences of large numbers of ferrocement slabs lying on the bottom of shallow bays is unknown. In highly capitalized fisheries, despite significant efforts to limit effort by limiting the numbers of boats and traps, effort continues to increase, as best illustrated in the Western Australia P . cygnus fishery. The advent of sophisticated depth sounders and global positioning systems allow the fishers to place traps very precisely, and to operate in much deeper waters than in the past. Faster, more seaworthy, boats allow fishing further from shore and under weather conditions that formerly would have confined the boats to port. The increase in effort despite traditional limitations has led to either further effort limits, or the imposition of total allowance catch by region. It is clear that lobster populations can be heavily exploited by a number of methods: overfishing is not limited to overcapitalized fisheries. Effort limits or catch limits are effective only when accepted by the fishers, and this may be the next challenge for managers.

Perspectives

669

Lobsters do not respect national boundaries. Two aspects of their biology suggest that wide dispersion is the rule: a very long larval stage (6-22 months) and, in some species, long-distance migrations by the adults. Many authors have suggested that there is a single gene pool of Panulirus argus in the Caribbean, and that larval recruitment in one country depends on egg production in another. The state of Florida in the USA appears to be managing its fishery on the presumption that it is the beneficiary of larval recruits from upstream Caribbean nations. In contrast, Cuban fishery scientists suggest that a recruitment cell off the southern coast may make their fishery self-sustaining. Despite the long larval life of P . cygnus and estimates that the phyllosomas may range as far as 1500 km from the coast of Western Australia, there is no evidence that this species is found in other nations or, for that matter, in other states of Australia. In contrast, recent evidence suggests that there is gene flow from eastern Australia to New Zealand populations of Jusus edwardsii. The Torres Straits, between Australia and Papua New Guinea, see annual migrations of thousands of adult lobsters. It appears that the lobster (Panulirus ornatus) move to breeding grounds in the eastern Gulf of Papua. As of now, the fishery is not heavily exploited in either country. Fisheries management becomes far more complex when national boundaries are crossed and competing management goals must be addressed. The situation is by far the most intricate in the Caribbean region, where complex current patterns create unknown recruitment relationships, and fishermen in many nations compete for catch in what may be a single, or at most, only a few, populations. In the past 40 years, lobster stocks have gone from moderately to heavily exploited in most areas. In developed countries, research in support of management has become increasingly sophisticated, and from this we have learned a great deal about the management of lobster populations. Nevertheless, there is a great deal yet to learn. An experimental approach to management may facilitate and even hasten the acquisition of knowledge on how best to manage these valuable fishery resources. Lobsters have a complex life cycle, that is, they have two quite different developmental stages, each requiring a different habitat. The larval and puerulus stages are found in the pelagic oceanic environment, while the juvenile and adult stages live an epibenthic existence. This single observation provides coherence to much of the research and management efforts directed towards spiny lobsters. To make a sweeping generalization, the oceanic phase is most subject to environmental fluctuation and thus density-independent processes during dispersal, while the juvenile and adult phases are subject to more constant conditions, remain somewhat more local, and are more likely to be subject to density-dependent population regulation. The extremely long and wide-ranging larval phase, along with longdistance migrations of the adults of a few species, make studies of stock identity necessary for lobster fishery biologists. The wide variation in ocean climate suggests that if stock-recruitment predictions are to be made, knowledge of effects of environmental variation on larval recruitment is necessary. In the benthic phase, habitat of food limitation may bring about high mortality rates and directly affect

610 Spiny Lobsters: Fisheries and Culture

recruitment to the fishery. Both phases of the life cycle must be integrated into models which attempt to describe the dynamics of the fishery and make predictions of future catches. The need for such information across all parts of the life cycle is aptly illustrated by the surprise for North American lobster biologists who, after years of predictions of dire consequences in Homaus americanus, saw catches increase by 50% or more in the last decade. Hypotheses abound, but as yet there is no well-accepted explanation for the remarkable increase. Clearly, greater understanding of the ecology of the animal is needed. The genetic techniques used by Ovenden and Brasher (Chapter 16) provide a great advance over earlier electrophoretic studies because mitochondria1 (mt)DNA analysis is more sensitive and finds variation where allozyme analysis did not. The case study reported here is directed towards stock analysis, but the technique may be extraordinarily useful in asking a wide variety of ecological questions. Are there differences between among larvae spawned early in the season and those that are spawned late? Are early (or late) larvae at a competitive advantage? Are there substock processes in long-distance migrations of the adults? What are the phenotypic correlates of mtDNA sequence variations, and can they be exploited in aquaculture? Molecular biology is only just beginning to have an impact on ecology and fisheries biology, but eventually it is likely to revolutionize our thinking by making the analyses that can be performed more directly related to the relationships within and between populations. There are few well-documented stock-recruitment relationships (SRR) for crustaceans. In P. cygnus there is a long enough record of puerulus abundance to allow correlations with subsequent catches in the fishery, as well as with estimates of spawning stock. The lack of relationship between spawning stock and the index of puerulus settlement suggests the strong influence of density-independent environmental effects on larval loss and mortality. However, the relatively close relationship between puerulus settlement and subsequent recruitment to the fishery allows catch predictions to be made. It is not clear to what extent density-dependent processes act in the juvenile phase, although the availability of habitat has been suggested as a possible limiting factor. Butler and Herrnkind (Chapter 15) make an interesting point in the conclusion of their chapter, indicating that there is nothing that a fishery manager can do to affect larval delivery, since it is regulated by oceanic processes. However, survival of the benthic post-puerulus may be enhanced by the provision of abundant shelter. Thus, environmental manipulation may be able to remove a bottleneck and increase production. Much the same type of reasoning has been applied to the use of artificial shelters for larger animals. Clearly, further work is needed to determine the extent of predator-mediated density-dependent population regulation and possible mitigating effects. The Western Australians have had remarkable success in predicting catches in the fishery based on a long and intense programme of research and monitoring of the fishery. It is tempting to think that their success could be duplicated in other fisheries, and there are now indications that this may be possible. Not only is truly

Perspectives

671

significant research effort required, but other factors appear to make the situation in P. cygnus unique. First, all puerulus that arrive on the coast of Western Australia must have been derived from the coast. Secondly, the adults do not make longdistance migrations. Thirdly, the fishery has been monitored practically since its inception, and thus data from times when stock were high and effort was low are available. Finally, the entire fishery is contained within a single administrative boundary, making both uniform record-keeping and integrated management practices possible. An alternative may be the approach of experimental management mentioned earlier. Were it possible to work with fishermen to set aside experimental areas, specific hypotheses about differing management practices could be tested. This type of research may be no less difficult to accomplish than the more traditional fisheries biology, passive adaptive management approach currently practised in spiny lobster fisheries, but addresses the question of how management actions affect the fisheries more directly. Aquaculture of spiny lobsters is dealt with in some detail in this book and it is certainly the topic of the moment. Studies of spiny lobsters have shown that the juveniles and adults have relatively wide environmental tolerances and many behavioural, feeding and growth characteristics that make it a suitable animal for commercial culture. Perhaps the most important of these is that, in contrast to clawed lobsters, which because of their aggressive behaviour, must be held individually, spiny lobster juveniles can be held very successfully in communal rearing systems at much lower cost because of their gregarious behaviour. They adapt well to the artificial conditions and the feeding regimes of culture systems and their rates of growth can be increased markedly over individuals in their natural environment, by culturing at elevated temperatures. The major negatives preventing funding of the rock lobster mariculture projects are the high cost of research and development, the long time to initial returns for an investor and the low returns typical of an agricultural industry. Japanese scientists appear to have the confidence of their government and with this support, they have made rapid advances on the way to a mariculture industry. It is a long step from the laboratory to a commercial operation, but all of the indicators are favourable. During the last decade, it has become obvious that the catching sector of the lobster fisheries is no longer isolated from the marketing and distribution sectors. Although their is still a market for all of the lobsters that are caught, timing of supply and competition between countries are changes associated with modern technology, and strongly affect the profitability of the fishers. Integration of the whole process is becoming necessary to maintain competitiveness. Prices for lobsters have changed dramatically and this is most clearly seen in the development of the live lobster trade, particularly with Japan. In the final two chapters several of these aspects are dealt with in detail and provide valuable insights into the marketing and distribution processes.

672 Spiny Lobsters: Fisheries and Culture

References McAllister, M.K.& Peterman, R.M. (1992) Experimental design in the management of fisheries: a review. N . Am. J. Fish. Manage., 12, 1-18. Walters, C.J. & Hilborn, R. (1976) Adaptive control of fishing systems. J. Fish. Res. Bd. Can., 33, 145-69.

SPINY L0BSTERS:FISHERIES AND CULTURE B.F. PHILLIPS&J. KITTAKA CoDvriaht 02000 bv Fishina News Books

Index Aquaculture diets, and stability, 619 larval feeding, 617 Panulirus japonicus, 619 Panulirus prospectus, 465 Artemia post-larvae, diet for Panulirus argus, 618 Artificial diets Panulirus argus, 618 phospholipids, 614 Artificial enhancement of natural populations, 293 Artificial reefs, 231 Mexico, 420 Artificial shelters, Cuba, 400 Artisanal fishery, 153 Australasia, recreational fishing, 457 Australia catch prediction, 357 genetics Jasus edwardsii, 308 Jasus verreauxi, 308 marketing, 641 rock lobster fisheries, 45 Baja Mexico, catches, 325 Behaviour, 406 Panulirus argus, 431 Belize, fishery, 162 Brasil catches, 325 fishery, 121 Bully nets, 138, 189 Campo system, 442 Carotenoid/chlorophyll ratio, 537 Casitas, 178 construction, 421 ecology, 423, 428 Mexico, 420 Catch prediction, 357 Central America catches, 156 management, 163

spiny lobsters, 153 Chapingorro, 138 Collectors, 282 Colour of exoskeleton, 625 taste, and, 625 Corsica, fishery, 203 Costa Rica, fishery, 157 Cuba catch prediction, 363 catches, 325, 416 fishery, 135 pesqueros, 400 Culture growout conditions, 569 Japan, 508 juveniles, 557 larvae, 508 puerulus, 556 system, 509 phyllosoma, 544 Density-dependent processes, 286 Diet, Homarus americanus, protein and amino acids, 611 Digestion, Panulirus japonicus, 611 Digestive system, morphology, 601 Disease Aeroccus viridans var. homari, 588 bacterial, 588 gaffkemia, 588, 595 shell disease, 590 vibriosis, 592 fungal, 592 parasitic, 593 viral, 588 Distribution, 12 Economic studies, Panulirus cygnus, 341 Ecuador, GalaÂpagos Islands, fishery, 210 El NinÄo/Southern Oscillation, Panulirus cygnus, 322 Environment catches, 321

673

674 Index Environment (continued) currents and genetics, 316 greenhouse, 332 Leeuwin current, 323 Panulirus cygnus, 321 rainfall, 331 sea level, 328 sea-surface temperature, 329 Southern Oscillation Index, 326 spawning, 487 Escape gaps, 388 Exoskeletal pigments, 625 Feeding, attractants, 617 Fishing effort, measurement, 334 Forecasting of stocks from puerulus and juvenile indices, 292 France, fisheries, 200 Fusarium, 592 Gaffkemia, 588 GalaÂpagos fishery, 210 catches, 212 management, 215 Genetics Homarus americanus, 303 Jasus edwardsii, 302 Jasus verreauxi, 302 Panulirus marginatus, 302 research, 317 techniques, 304 Global positioning systems, 396 Growout, 556 diseases, 573 endocrine factors, 573 food, 570 oxygen, 572 salinity, 570 systems, 508 temperature, 569 water quality, 571 Haematodinium, 594 Homarus americanus catches and sea-surface temperature, 330 diet and moult death, 616 genetics, 303 nutrition, 611 vitamins, 616 Homarus gammarus, 207

catches and sea-surface temperature, 330 diet cholesterol, 614 fatty acids, 613 juvenile, 618 Honduras, fishery, 161 Hookah gear, 178, 210 Ibacus ciliatus culture, 222 digestive system, morphology, 601 Ibicus novemdentatus culture, 222 Japan catches, 325 fishery, 221 imports, 656 marketing and distribution, 655 production and consumption, 655 restocking, 221 Jasus edwardsii Australia biological model, 377 catch prediction, 357 catches, 45 culture, 508, 565 ecology, 80 fishery, 54 genetics, 302, 306 growth, 55 juveniles, 286 larvae, 81 management, 59, 82 maturation, 477 culture, 525 migrations, 14 New Zealand, 78, 376 copulation, 489 genetics, 303 hatching of eggs, 496 multiple mating, 490 pueruli, 557 spawning, 481 temperature, 487 reproduction in captivity, 500 spawning, 481 status of the stock, 61 stock structure, 84 Jasus lalandii catches, 112

Index culture, 222, 508, 522 environmental effects, 107 fishery, 105 genetics, 305 larval development, 18 prey, 15 recreational fishing, 458 reproduction, 246, 474 in captivity, 500 size at maturity, 479 spawning, 481 Jasus novaehollandiae taxonomy, 54 Jasus spp. culture, 508, 522 distribution, 8 genetics, 81 habitat use, 13 Jasus tristani catches, 115 fishery, 105 genetics, 306 Jasus verreauxi catches, 45 culture, 525 fecundity, 494 fishery, 49 genetics, 302, 306 management, 51 migrations, 14 New Zealand, 78 reproduction, 262 in captivity, 501 size, 10, 50 status of the stock, 52 Jaulones, 138 Justitia, 91 Juvenile ecology, 276 feeding, 289 growth, 291 mortality, 288 population regulation, 291 shelter use, 285 social behaviour, 287 Lagenidium, 593 Larvae ecology, 16 naupliosoma, 17 phyllosoma, 15

prenaupliosoma, 17 sensitivity to light, 18 Linuparus, habitat use, 13 Madagascan fishery, 117 marketing pack styles, 647 processing, 645 product forms, 641 Marketing rock lobsters Australian, 641 New Zealand, 641 Markets, 648 Maturation, 474 Melanosis, 626 Mexico, fishery, 169 Microalgae, culture, 533, 535 Microsporidiosis, 593 Mitochondrial DNA analysis, 302 Morphology, 10 Mortality, juveniles, 288 Mytilus edulis phyllosoma culture, 533 Namibia, fishery, 107, 111, 126 Nannochloropsis culture, 535 Nemertine worms, 594 New Zealand bioeconomic modelling, 376 catch prediction, 362 catches, 325 and environment, 330 genetics Jasus edwardsii, 308 Jasus verreauxi, 308 marketing, 641 rock lobster fisheries, 78 Nicaragua, fishery, 159 Nutrition carotenoids, 617 fatty acids, 613 food, and, 611 juveniles, 618 larvae, Phaeodactylum sp., 617 larval feeding, artemia, 617 minerals, 615 Mytilus, 617 phospholipids, 614

675

676 Index Nutrition (continued) Standard Reference Diets, 611 sterols, cholesterol, 614 vitamins, 616 Old car tyres, 138 Palinurid commercial fisheries, 2 evolution, 8 migrations, 14 morphology, 7 sound emission, 11 Palinurus, habitat use, 13 Palinurus charlestoni, distribution, 200 Palinurus delagoae distribution, 105 fishery, 118 Palinurus elephas catches, 206 culture, 465, 526 distribution, 200 ecology, 202 egg bearing, 493 France, fisheries, 200 growth, 205 larval development, 18 management, 208 maturation, 477 reproduction, 204 in captivity, 500 stocks, 207 Palinurus gilchristi distribution, 200 ecology, 203 Palinurus vulgaris, 200 Palinustus, habitat use, 13 Panama, fishery, 156 Panulirus distribution, 8 habitat use, 13 Panulirus argus artisanal fishery, 153 Brazil, 121 catches and Southern Oscillation Index, 328 catch prediction, 357 catches, 190 sea-surface temperature, and, 329

copulation, 489 Cuba catches and Southern Oscillation Index, 326 culture, 558 rainfall, 331 stocks, 146 day length, 487 diet, artemia, 613 ecology, 136, 139, 409, 425, 430 egg bearing, 493 eyestalk ablation, 481 feeding, stimulants, 617 fishery, 153 Brazil, 122 Cuba, 135, 136 Yucatan, 177 Florida fishery, 189 management, 192, 195 genetics, 316 growth, 142 juveniles, 277, 286 larval movements, 18 management Cuba, 147 Mexico, 169, 420, 434 catches, 436 stocks, 180 migrations, 14 mortality, 145 multiple mating, 490 number of broods, 496 puerulus, 282, 557 reproduction, 410 temperature, 487 Panulirus cygnus abundance estimates, 349 catch fishing effort, and, 334 prediction, 323, 357 catches, 334 commercial catch monitoring, 339 sea-level, and 328 sea-surface temperature, 329 Southern Oscillation Index, and, 328 commercial fishery data, 338 culture, 562 ecology, 337

Index economics, 341 egg bearing, 493 extrusion, 492 fishery, 62 fishing power, 345 illegal fishing, 342 input vs output controls, 73 juvenile diet, 618 log books, 342 management, 66 migrations, 14 modelling, 386 moulting and mating, 486 number of broods, 496 ocean climate, 321 puerulus, 1, 339 rainfall, and puerulus, 331 recreational fishing, 343, 453 reproduction, 65, 263 size at maturity, 251 spawning stock, 341 status of the stock, 69 stocks, 35 taxation, 341 temperature, 487 vertical larval movements, 18 Panulirus echinatus, 121 Panulirus gracilis breeding, 487 fishery, 212 Mexico, 169 number of broods, 496 Panulirus guttatus juveniles, 286 Mexico, 169 reproduction, 247 Panulirus homarus culture, 561 distribution, 90 egg bearing, 493 eyestalk ablation, 481 spawning, 481 Panulirus homarus homarus Japan, fishery, 221 size at maturity, 478 Panulirus homarus rubellus copulation, 489 maturation, 477 spawning, 479

Paulirus inflatus breeding, 487 Mexico, 169 number of broods, 496 Panulirus interruptus Brazil, catches and sea level 328 catches and sea-surface temperature, 329 culture, 563 fecundity, 494 feeding, stimulants, 617 growth, 173 juveniles, diet, 618 management, 172 Mexico, 169 fishery, 173 Panulirus japonicus catches, 226 copulation, 479, 489 culture, 222, 508, 525, 564 currents and puerulus, 330 diet cholesterol, 614 fatty acids, 613 digestion, 611 digestive system and morphology, 601 distribution, 487 ecology, 223 egg bearing, 493 extrusion, 492 eggs, 495 fecundity, 493 fishery, 2221 Japan, juveniles, 286 juvenile, artificial diets, 619 larval development, 18 management, 233 maturation, 478 microflora, 634 multiple mating, 490 number of broods, 496 reproduction, 246, 474 in captivity, 499 size at maturity, 478 spawning, 479, 480 temperature, 487 Panulrius laevicauda Brazil, 121

677

678 Index catches and Southern Oscillation Index, 328 catches and sea-surface temperature, 329 fishery, Brazil, 122 multiple mating, 490 Panulirus longipes femoristriga culture, 525 distribution, 90 Japan, fishery, 221 Panulirus longipes longipes, 247 distribution, 90 Panulirus marginatus catches and sea-level, 330 fishery, 91, 98 genetics, 302 management, 101 reproduction, 252 stocks, 102 Panulirus ornatus catch prediction, 357 catches, 45 culture, 561 distribution, 90 ecology, 91 fishery, 45 growth, 46 management, 49 migrations, 14 post-reproduction mortality, 47 reproduction, 262 stock status, 49 Panulirus pascuensis, distribution, 90 Panulirus penicillatus breeding, 487 distribution, 90 egg bearing, 493 fishery, 91, 212 number of broods, 496 reproduction, 474 Panulirus polyphagus culture, 561 fishery, 91 Panulirus versicolor breeding, 487 distribution, 90 ecology, 91 Japan, fishery, 221 number of broods, 495 Parribacus antarcticus, fishery, 98 Pesqueros, 138 catches, 404, 416

construction, 400 ecology, 413 fishing technique, 403 Phyllosoma bacteria, 549 culture, 465 ammonia-N, 541 chemical oxygen demand (COD), 542 digestive system, 603 food and feeding, 512 growth, 517 heavy metals, 543 microflora, 544 pH, 541 salinity, 539 water quality, 533 temperature, 538 Post-larvae, puerulus, 16 Pueruli, culture, 557 Predators, Panulirus argus, 412 Pre-recruits, Panulirus cygnus, 339 Prey, 12 Processors' monthly returns, Panulirus cygnus, 338 Projasus, habitat use, 13 Projasus parkeri, catches, 78 Propagation, Japan, 508 Puerulus, 91, 223 culture, 468, 520 ecology, 276 habitat use, 13 Panulirus cygnus, 339 recruitment and spatiotemporal patterns, 281 settlement habitat, 1 supply to coastal nurseries, 278 Recreational fisheries, 447 management regulations, 448 Recreational fishing catch and effort, 454 illegal, 453 Recruits to the fishery, 339 Reproduction, 245 breeding, 485 periods, 253 copulation, 489 behaviour, 479 courtship, 489 egg

Index bearing, 493 development, 495 production, 256 environment, 487 eyestalk ablation, 481 fecundity, 493 female choice, 488 female pre-spawning behaviour, 492 fertilization, 16 oviposition, and, 492 hatching of eggs, 496 internal reproductive system female, 476 male, 474 mating, 486 multiple, 490 success, male, 487 migrations, 262 number of broods, 495 ovary and oocytes, 476 Panulirus cygnus, 263 sexual maturity, 246 size at maturity effects of fishing, 251 Jasus lalandii, 479 Panulirus homarus homarus, 478 Panulirus japonicus, 478 spawning New Zealand Jasus edwardsii, 479 Panulirus homarus rubellus, 479 Panulirus polyphagus, 479 spermatophore, 491 time of spawning, 479 stock periods, 253 recruitment, and, 259 Research log books, Panulirus cygnus, 338 Restocking, Japan, 227 Sanctuary areas and reproduction, 262 Scyllarides astori, fishery, 98

679

Scyllarides brasiliensis, Brazil, 121 Scyllarides haanii, fishery, 98 Scyllarides squammosus, fishery, 98 Shell disease, 590 Shipping, 633 bacteria, 634 containers, 633 oxygen, 638 packing materials, 636 salinity, 636 starvation, 636 Skin diving and Panulirus argus, 178 Sociality and juveniles, 287 South Africa fishery, 107 recreational fishing, 458 South-east Atlantic, fishery, 105 Spawning stock, Panulirus cygnus, 341, 391 Spiny lobsters, tropical Indo-Pacific, 90 Tangle nets, 178, 207, 226 Taste, 628 Trammel nets, 207 Traps, 92, 189, 192, 206, 334 Belize, 155 dema, 91 Panulirus interruptus, 174 soak time, 344 unbaited, 138 Tsukiji market Japan, 661 USA Florida, fishery, 189 Hawaiian Islands, fishery, 98 Vibriosis, 592 Western Australia catches, 325 Panulirus cygnus, modelling, 386