lUCN Species Survival Commission

The Species Survival Commission (SSC) is one of six volunteer commissions of IUCN - The World Conservation Union, a union of sovereign states, government agencies and non­governmental organizations. IUCN has three basic conservation objectives: to secure the conservation of nature, and especially of biological diversity, as an essential foundation for the future; to ensure that where the earth’s natural resources are used this is done in a wise, equitable and sustainable way; and to guide the development of human communities towards ways of life that are both of good quality and in enduring harmony with other components of the biosphere.

The SSC’s mission is to conserve biological diversity by developing and executing programs to save, restore and wisely manage species and their habitats. A volunteer network com prised of nearly 7,000 scientists, field researchers, government officials and conservation leaders from 188 countries, the SSC membership is an unmatched source of information about biological diversity and its conservation. As such, SSC members provide technical and scientific counsel for conservation projects throughout the world and serve as resources to governments, international conventions and conservation organizations.

The IUCN/SSC Occasional Paper Series focuses on a variety of conservation topics including conservation overviews on a regional to taxonomic basis and proceedings of important meetings.

IUCN/SSC also publishes an Action Plan series that assesses the conservation status of species and their habitats, and specifies conservation priorities. The series is one of the world’s most authoritative sources of species conservation information available to nature resource managers, conservationists and government officials around the world.

IUCN Species Survival Commission Rue Mauverney 28, CH-1196 Gland, Switzerland. Tel: + +41 22 999 01 53, Fax: + +41 22 999 00 15 E-mail: lwh@hq.iucn.org

IUCN Publications Services Unit,219c Huntingdon Road, Cambridge, CB3 ODL, UK. Tel: + +44 1223 277894, Fax: + +44 1223 277175 E-mail: iucn-psu@ wcm c.org.uk

IUCNThe World Conservation Union

The IUCN Species Survival Commission

Sharks and their Relatives

Ecology and Conservation

Merry Camhi, Sarah Fowler, John Musick, Amie Bräutigam and Sonja Fordham

Occasional Paper of the IUCN Species Survival Commission No. 20

IUCNThe World Conservation Union

Donors to the SSC Conservation Communications Programme and Sharks and their Relatives

The IUCN/Species Survival Commission is committed to communicate im portant species conservation inform ation to natural resource managers, decision-makers and others whose actions affect the conservation of biodiversity. The SSC’s Action Plans, Occasional Papers, news magazine ( Species ), Membership Directory and other publications are supported by a wide variety of generous donors, including the following:

The Sultanate o f Oman established the Peter Scott IU CN /SSC Action Plan Fund in 1990. The Fund supports Action Plan development and implementation; to date, m ore than 80 grants have been made from the Fund to Specialist Groups. As a result, the Action Plan Program m e has progressed at an accelerated level and the network has grown and m atured significantly. The SSC is grateful to the Sultanate of Om an for its confidence in and support for species conservation worldwide.

The Chicago Zoological Society ( C Z S) provides significant in-kind and cash support to the SSC, including grants for special projects, editorial and design services, staff secondments and related support services. The mission of CZS is to help people develop a sustainable and harm onious relationship with nature. The Zoo carries out its mission by inform ing and inspiring 2,000,000 annual visitors, serving as a refuge for species threatened with extinction, developing scientific approaches to manage species successfully in zoos and the wild, and working with other zoos, agencies, and protected areas around the world to conserve habitats and wildlife.

The Council o f Agriculture ( COA ) , Taiwan has awarded m ajor grants to the SSC’s W ildlife Trade Program m e and Conservation Com m unications Program m e. This support has enabled SSC to continue its valuable technical advisory service to the Parties to CITES as well as to the larger global conservation community. Am ong other responsibilities, the COA is in charge of m atters concerning the designation and m anagem ent of nature reserves, conservation of wildlife and their habitats, conservation of natural landscapes, coordination of law enforcement efforts as well as prom otion of conservation education, research and international cooperation.

The World Wide Fund for Nature (W W F ) provides significant annual operating support to the SSC. W W F’s contribution supports the SSC’s minimal infrastructure and helps ensure that the voluntary network and Publications Program m e are adequately supported. W W F aims to conserve nature and ecological processes by: ( 1 ) preserving genetic, species, and ecosystem diversity; (2 ) ensuring tha t the use of renewable natural resources is sustainable both now and in the longer term; and (3) prom oting actions to reduce pollution and the wasteful exploitation and consum ption of resources and energy. W W F is one of the w orld’s largest independent conservation organizations with a network of N ational Organizations and Associates around the world and over 5.2 million regular supporters. W W F continues to be known as W orld Wildlife Fund in Canada and in the United States of America.

The Department o f the Environment Transport and the Regions, UK (D E TR ) supports a Red List Officer post at the SSC Centre in Cambridge, U K , where the SSC Trade Program m e staff are also located. The D ETR also supported the work of the Shark Specialist G roup on CITES issues in 1996, including preparation of the original Shark Specialist G roup report to the CITES Animals Committee, on which this Occasional Paper is based. Together with two other G overnm ent-funded agencies, Scottish N atu ra l Heritage and the Royal Botanic Gardens, Kew, the D ETR is also financing a specialist plants officer. F urther support for the SSC Centre is being offered by two N G O members of IU CN : the W orld Wide Fund for N ature - U K and Conservation International, US.

The National Audubon Society (N A S ) through their Living Oceans Program, provides staff and logistical support to the Shark Specialist G roup, including the preparation of the original report and this revision. Living Oceans is dedicated to the conservation and restoration of the oceans’ giant fishes, including sharks, tunas, and billfishes, and is a m ajor sponsor of Shark News and other IU C N Shark Specialist G roup activities.

The Center fo r Marine Conservation ( C M C ) provides financial and in-kind support to the work of the SSC Shark Specialist G roup and other SSC marine species specialist groups and to the broader marine activities of the Species Survival Commission.

The Nature Conservation Bureau Limited supports the work of the Shark Specialist G roup through donation of staff time and office facilities.

The Virginia Institute o f Marine Science has supported this Occasional Paper through C ontribution #2167.

The IUCN Species Survival Commission

Sharks and their Relatives

Ecology and Conservation

Merry Camhi, Sarah Fowler, John Musick, Amie Bräutigam and Sonja Fordham

Occasional Paper of the IUCN Species Survival Commission No. 20

IUCNTk* W o rid C o n M rv a tio n U nion S i' e c i c s S u r v i v a l C o m m i s s i o n

C h ic a g o Z o o lo g ic a l S t v i e l y A D E T REHVMOMMCN

YRAM SPO UT

R f Ç t Q H S

OCEANS ©Center for Marine Conservation The N ature Conservation Bureau Ltd

The designation of geographical entities in th is book, and the presentation o f the material, do not imply the expression of any opinion whatsoever on the part o f IUCN concerning the legal status o f any country, territory, or area, or of its authorities, or concerning the delim itation of its frontiers or boundaries.

The opinions expressed in th is volume do not necessarily reflect those o f IUCN.

Published by: IUCN, Gland, Switzerland, and Cambridge, UK

Copyright: © 1998 International Union fo r Conservation of Nature and Natural Resources

Reproduction of th is publication for educational and other non-com mercial purposes is authorised w ithout prior written permission from the copyright holder provided the source is fu lly acknowledged.

Reproduction o f th is publication fo r resale or other comm ercia l purposes is prohibited w ithout prior written perm ission of the copyright holder.

C itation: Camhi, M., Fowler, S .L., Musick, J.A., Bräutigam, A. and Fordham, S.V. (1998) Sharks and their Relatives - Ecology andConservation. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK. iv + 39 pp.

ISBN: 2 -8317-0460-X

Cover photo: Grey reef shark, by Jeremy Stafford-Deitsch

Produced by: The Nature Conservation Bureau Ltd, Newbury, UK

Printed by: Information Press, Oxford, UK

Available from : IUCN Publications Services Unit219c Fluntingdon Road, Cam bridge CB3 ODL, UK Tel: +44 1223 277894, Fax +44 1223 277175 E-mail: iucn-psu@ wcmc.org.uk WWW: http ://w w w .iucn.org A catalogue o f IUCN publications is also available.

The text o f this book is p rin ted on 115 gsm Zone Silk, which is rated as 5 -sta r under the Eco-Check system and is made from 100% sustainable fibre sources using chlorine-free processes.

Contents

Executive Summary............................................................... iv

Acknowledgements .................................................................iv

Chapter 1: Introduction........................................................11.1 Conservation issues............................................. 11.2 B ackground ..............................................................1

Chapter 2: The Biology of the Chondrichthyan Fishes......32.1 C hondrichthyan diversity.................................... 32.2 Life history characteristics..................................32.3 Life history constraints on ex p lo ita tio n ..........4

Chapter 3: Overview of Exploitation and Other Threats .. 63.1 F ish eries ...................................................................63.2 B ycatch..................................................................... 93.3 H abita t loss and d eg rada tion ............................. 9

Chapter 4: Conservation S ta tu s....................................... 114.1 Extinction r isk ...................................................... 11

4.2 IU C N Red List assessments for sh a rk s............134.3 Species case s tu d ie s ............................................... 13

Chapter 5: Management of Chondrichthyan Fishes 185.1 Fisheries m anagem ent.......................................... 185.2 Species p ro te c tio n ................................................. 21

Chapter 6: Conclusions.........................................................226.1 S um m ary ................................................................. 226.2 Ecological data need s........................................... 226.3 Fisheries data n e e d s ..............................................226.4 M anagem ent m easures.........................................23

Annex 1: Life-history traits of somechondrichthyan species..........................................................24

Annex 2: Summary of the 1994 IUCN Red List Categories and Criteria.........................................................30

References............................................................................... 31

Executive Summary

Sharks and their relatives - the rays and chim aeras - are th e d iverse g ro u p o f c a r ti la g in o u s fishes (C lass Chondrichthyes ) tha t have evolved over 400 million years. Historically considered of low economic value to large- scale fisheries (and therefo re neglected by fishery m anagem ent agencies), today many of these fishes have become the target of directed commercial and recreational fisheries around the world, and are increasingly taken in th e b y ca tch o f fish e rie s ta rg e tin g o th e r species. U nfo rtunate ly , m ost sharks and the ir relatives are characterised by K-selected life history traits, including slow growth, late sexual m aturity, low fecundity and long life, resulting in low rates of population increase. Such life h isto ries m ake these species h igh ly vu ln erab le to overexploitation and slow to recover once their populations have been depleted.

Shark fisheries have expanded in size and num ber around the world since the mid- 1980s, primarily in response to the rapidly increasing dem and for shark fins, m eat and cartilage. Despite the boom -and-bust nature of virtually all shark fisheries over the past century, m ost shark fisheries today still lack m onitoring or management. For example, only a handful o f the 125 countries tha t are now involved in shark fishing and international trade have even the m ost m inim al m anagem ent in place, and there is still no m anagem ent for sharks fished on the high seas. As a result,

m any shark populations are now depleted and some are considered threatened.

Shark fishery m anagem ent has been ham pered by a lack of biological and fishery d a ta . G rowing international concern over the status of these species, however, has im proved this situation in recent years. This report emphasises the widely acknowledged need to improve shark fishery m onitoring, expand biological research and take m anagem ent action. Yet while species-specific data are still needed, lack of inform ation should not be used to justify the lack of management for these vulnerable animals. If any marine species demand precautionary management, as set out by the United N ations Food and Agriculture O rganization ( FAO ) Precautionary A pproach ( 1995 ), it is the sharks and their relatives, because of their well- docum ented vulnerability to overexploitation.

This report serves as an introduction to the ecology, status and conservation of the sharks and their relatives for a general audience. It draws attention to their unique biology and makes the case for expanded political and f in an c ia l in v estm en t in research , m o n ito rin g and precautionary m anagem ent for all fisheries taking sharks, skates, rays and chimaeras as part of their catch. Shark fisheries canno t be m anaged sustainably, nor shark p o p u la tio n s rem ain viable, in the absence o f new conservation and m anagem ent initiatives.

Acknowledgements

M uch o f the original con ten t o f this repo rt was w ritten and com piled by M erry C am hi and Sarah Fow ler in A ugust and Septem ber 1996, w ith substan tia l assistance from several m em bers o f the Shark Specialist G roup and other elasm obranch biologists. I t was revised by the present au tho rs for pub lication as an IU C N Species Survival C om m ission Occasional Paper. Two years after the com pletion o f the original, unau tho red paper, it is d iff ic u lt to reca ll a ll th o se w ho h ad g en ero u sly contributed, directly or indirectly, to the original version, o r helped to review it. We apologise if anyone who helped w ith the p rep a ra tio n of this pub lication has been om itted below.

We would particularly like to thank A lberto Am orim , C harles A nderson , R am ó n B onfil-Sanders, Steven

B ranstetter, Barry Bruce, G eorge Burgess, G reg Cailliet, Jo sé C a s tro , C h r is t in e C h a n -A -S in g , G u s ta v o C hiaram onte , L eonard C om pagno, Sid C ook, Enric C ortés, D om inique D idier, Jim Ellis, Ian Fergusson, M alcolm Francis, M anoel G onzalez, Sam uel G ruber, H ajim e Ish ihara , Peter Last, R osangela Lessa, M ark M arks, H enry M ollet, M adeleine O etinger, A ndrea Oliver, D ebra Rose, A lison R osser, C ari Safina, G lenn Sant, C olin S im pfendorfer, M alcolm Smale, Susan Sm ith, John Stevens, C arolus V ooren, P addy W alker, T erry W alker, K eith W olf and G eorge Zorzi.

Finally, our late colleague Sid C ook, form er regional vice-chair o f the Shark Specialist G ro u p ’s N o rth E ast Pacific R egion, was always extrem ely generous w ith his tim e and advice. We dedicate this pub lication to him.

iv

Chapter 1

Introduction

1.1 Conservation issuesChondrichthyan fish ( shark, ray and chimaera ) populations around the world are being affected both directly and indirectly by a wide array of hum an activities. As a result, many populations are depleted, and some species are considered to be threatened with extinction as a result of several factors:• life history strategies th a t m ake chondrichthyans

especially susceptible to over-exploitation and impede recovery of depleted populations;

• rapid growth in fisheries that are for the m ost part u n reg u la ted and p a r tly driven by u n re s tr ic ted international trade in shark products;

• very high levels of m ortality from bycatch (incidental take) in marine and freshwater fisheries; and

• degradation of im portant nursery grounds and other critical coastal, estuarine, and freshwater habitats from development, alteration, overfishing, and pollution.

Investment in research and management of the world’s chondrichthyan populations has historically been a low priority. Elasm obranch fisheries have had low levels of production relative to those targeting bony (teleost) fishes; the products have mostly beenless valuable; and significant numbers are taken as bycatch in other fisheries. In the few cases where fisheries have targeted high-valued species,

stocks have often collapsed before m anagem ent was introduced.

Today, few shark fisheries are managed, and m ost of those are inadequately controlled, due in part to a lack o f u n d ers tan d in g o f the lim ita tio n s o f tra d itio n a l teleost fisheries m anagem ent models when applied to elasmobranchs. The m ajor difficulties faced by researchers and managers attem pting to evaluate and manage shark and ray populations are the lack of available quality data, m anagem ent tools, and political will. E lasm obranch biology is generally poorly understood and little fishery- independent or taxonom ic research is under way. Fishing m ortality is not adequately calculated and m onitored because m ost fisheries generally do not identify or record their shark landings or bycatch, and landings may occur at a great distance from the catch source. The origin of shark products and num bers of sharks entering international trade are alm ost completely unrecorded. There are few published taxonom ic or distribution guides to enable the id en tifica tio n o f all species tak en in fisheries (no comprehensive batoid or chimaeroid catalogues exist, and m any species are still undescribed). Records are rarely kept to enable the identification of products to species or even genus level, and to m onitor changes in trade and catch patterns. Finally, few existing m anagem ent models take into account the unique biology and state of knowledge of chondrichthyans.

Even with excellent data and management tools, the particularly vulnerable nature of chondrichthyan fishes necessitates a very conservative approach to management if populations are to rem ain viable, fisheries sustained, and threatened species not driven to extinction. In the absence of basic data, however, it is difficult for biologists and managers to assess the impacts of fisheries and international trade on elasm obranch populations, reverse declining population trends, achieve effective management, and ensure that fisheries can continue to supply products to domestic markets and international trade. A precautionary approach to management must, therefore, be stringently applied.

1.2 BackgroundThe Shark Specialist G roup was established by IU C N - The W orld Conservation Union as part of its Species Survival Commission in 1991. The G roup was formed to assess and address the conservation needs of sharks, rays and chimaeras ( the cartilaginous or chondrichthyan fishes ).

Taxonomy and terminology

The term ‘sh a rk ’ ¡so ften used generica lly to refer to all o f the chondrich thyan o r ca rtilag inous fishes, taxonom ic Class C hond rich thyes . ‘S h a rk ’ is used in th is sense by the C onvention on In ternational Trade in Endangered S pecies (CITES), in the present FAO Technical C onsu lta tion , and in the Shark S pecia lis t G roup 's name.

T h is re p o r t d e a ls w ith a ll m e m b e rs o f th e C la s s C hondrich thyes, bu t endeavours to d is tingu ish betw een the th ree main g roups o f chondrich thyan fishes: sharks, rays (also know n as ba to id fishes) and chim aeras.

The h igher sys tem atic organ isa tion o f the chondrich thyan fishes is:Class Chondrichthyes: sharks, rays, and chim aeras.

Superorder Elasmobranchii: s h a rk s an d rays . (E lasm obranch m eans literally ‘s trap g ili’ ; ‘rays ’ inc lude the saw fishes, gu ita r fishes, e lec tric rays, skates and stingrays.)

Superorder Holocephali: chim aeras. (The ch im aeras are a m ore d is tan tly related, poorly know n g roup o f m ostly deepw ate r fishes th a t do no t appear in as w ide a range o f ta rge t and byca tch fisheries as the e lasm obranchs.)

1

Its members are completing a Status R eport ( Fowler et a l in press b) and preparing an Action Plan for these groups (Fowler et al. in preparation). The Status R eport briefly reviews the status of regional populations and fisheries, the regional and global conservation status of a selection of species, and the current and potential threats to their survival. The G lobal Action Plan will identify the actions needed to ensure the maintenance of healthy chondrichthyan populations and the recovery of depleted and threatened species.

This report is drawn in part from the Status R eport. It provides a summary of the biological characteristics and status of chondrichthyan fishes as well as implications for their conservation and management. The first version of this report was submitted by the Shark Specialist G roup (SSG) to the 13th meeting of the Animals Committee for the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) in 1996, and has since been revised and updated.

A t their ninth biennial meeting in 1994, the CITES Parties directed the CITES Animals Committee to compile a review of data on the biological and trade status of shark species subject to in ternational trade for the Parties’ consideration at their next meeting. The CITES Animals Committee presented their review (Anon. 1997) to the tenth CITES meeting in H arare, Zimbabwe (June 1997). T h is re p o r t reco g n ised th e v u ln e ra b le n a tu re o f chondrichthyans, danger of rapid population collapse, lack o f a c c u ra te fish e rie s d a ta , an d p a u c ity o f in fo rm ation on in te rna tiona l trade. It presented a series of recommendations, including a request that the U N Food and Agriculture Organization (FAO) undertake an inquiry on the availability of biological and trade data on

chondrichthyans, and undertake a consultation of experts to develop a program m e to implement shark fishery data collection and management.

This FAO assessment is under way, under the auspices of a Technical Consultation on the M anagem ent o f Shark F isheries m an d ated a t the 1997 session o f F A O ’s C om m ittee on Fisheries (C O FI), and will culm inate in an intergovernm ental meeting in October 1998. This Consultation has developed guidelines for sustainable global and regional shark management as part of a Plan of Action fo r Sharks for p rom oting and im plem enting shark conservation and m anagem ent (FAO 1998), and has p roduced the overview o f chondrich thyan fisheries requested by CITES. D raft reports of the FA O Regional W orkshops held in preparation for the consultation are also available (Oliver and W alker 1998 a, b, c).

In addition to the present paper, two other reports were submitted to the CITES Animals Committee in 1996 and are no w available. An examination of shark fisheries around the world was prepared by the U SN ational Marine Fisheries Service (NM FS) (Oliver 1997) and a summary paper by T R A F F IC Oceania and T R A FFIC USA ( 1996) (based on several regional studies summarised in Rose 1996 ) addressed international shark trade. Subsequently, a report prepared by the Center for M arine Conservation and T R A FFIC (Weber and Fordham 1997) presented options for regional and international shark management. Since then, a series of regional reports on international trade in sharks has been published by TR A FFIC , and regional summaries of th e s ta tu s o f c h o n d ric h th y a n fisheries and th e ir management, commissioned by FAO from national experts, will be published later in 1998. M any SSG members have contributed to these studies.

2

Chapter 2

The Biology of the Chondrichthyan Fishes

2.1 Chondrichthyan diversityThe over 1,000 species o f chondrichthyan (cartilaginous) fishes include the sharks (c. 400 species, not all described), batoid fishes (including skates, stingrays, guitarfishes and sawfishes - c. 600 species, not all described), and ch im aero id fishes (c. 30+ species, p o o rly know n w ith confused taxonom y) (C om pagno in press b). Chondrichthyans occupy a wide range of habitats, including freshwater riverine and lake systems, inshore estuaries and lagoons, coastal waters, the open sea, and the deep ocean. Although sharks are generally thought of as wide-ranging, only a few ( including many commercially im portant species ) make oceanic migrations. M ost species of chondrichthyan fishes have a more restricted distribution ( Last and Stevens (1994) identify 54% of the Australian chondrichthyan fauna as endemic), occurring mainly along continental shelves and slopes and around islands, and some are also confined to narrow depth ranges. Overall, some 5% of chondrichthyan species are oceanic (found offshore and probably migrating routinely across ocean basins), 50% occur in shelf waters to c. 200 m depth, another 35% are found in deeper waters (200-2,000 m), 5% occur in fresh water, and 5% have been recorded from several of these habitats.

The chondrichthyans are predom inantly predatory; however, some are also opportunistic scavengers, and some of the largest (whale, basking and m egam outh sharks, and m anta rays) filter-feed on p lankton and small fishes, like the baleen whales. Predatory sharks are apex predators, found at or near the top of marine food chains. W herever they occur, therefore, their numbers are naturally limited by the carrying capacity of the ecosystem and are relatively low compared to those of most teleost fishes.

The biology of the chondrichthyan fishes is among the least known and understood of that o f any m ajor marine faunal group. Inform ation on life history, reproductive biology and population dynamics is available only for those few species tha t are of im portance for fisheries. Logistically, it is extremely difficult, if no t virtually im possible, to collect these sorts o f da ta for m ost populations, particularly those th a t are restricted to deepwater habitats or tha t are sampled only at certain times of the year or stages in the lifecycle. The ecological importance of sharks, such as their role as predators in complex fish communities, is virtually unknown. It is likely that sharks, like apex predators on land, play an im portant role in the structure and function of marine communities.

2.2 Life history characteristicsThe life history of an organism is determined by the biological features of its lifecycle (e.g. fecundity, growth rate, mortality) and the strategies tha t influence its survival and reproduction. The size and grow th (rate of increase) of a population of the species can be calculated if life history param eters such as rates of birth, recruitm ent (taking into account im m igration and emigration) and m ortality are known. In general, chondrichthyans have life histories characterised by:• low fecundity;• large, precocious young;• slow growth;• late maturity;• long life; and• high survival of all age classes.

This suite of life history characteristics results in low reproductive potential and low capacity for population increase (Pratt and Casey 1990). This is because sharks, generally top predators with few natural enemies, need to produce very few young capable of reaching m aturity in order to m aintain population levels at the carrying capacity o f the ecosystem. Species w ith life histories such as these have often been called ‘K -selected’. These life h istory characteristics have serious im plications for chondrichthyan populations, as they limit the capacity of populations to recover from over-fishing or other negative impacts (Holden 1974).

Of the chondrichthyan fishes for which age and growth data are available, many are very long-lived - up to 70 years in the spiny dogfish Squalus acanthias (Ketchen 1975, N am m ack et al. 1985, Beamish and M cFarlane 1987) - and very slow to reach m aturity. Age to m aturity ranges from the exceptionally short one and three years in th e sh a rp n o se sh a rk s R h izo p rio n o d o n ta y lo r i (Simpfendorfer 1993) and Rhizoprionodon terraenovae (Branstetter 1987a) respectively, to 20-25 years in the dusky shark Carcharinus obscurus (N atanson et al. 1995 ). M ost species, however, have no t been aged, and cannot be aged reliably except through the use of detailed tagging and recapture or with the study of validated grow th rings on vertebral cartilage (Cailliet et al. 1986).

Annex 1 summarises available inform ation (including literature sources) on life history traits and geographical distributions for 41 species of elasmobranchs. The species’ actual or potential exposure to fisheries is also noted. M ost o f the species are featured here because they are

3

tak en in large-scale fisheries o r are im p o rta n t in international trade. A few species, however, are included because of their rarity, dependence on a very restricted habitat, or some other distinguishing tra it tha t means they are of particular conservation concern.

There are three main patterns of embryonic development in chondrichthyans, all o f which involve considerable m aternal investment to produce small numbers of large, fully-developed young with relatively high natural survival rates (Ham lett 1997). Internal fertilisation of relatively few eggs is followed by either:• attachm ent of the embryo by a placenta (placental

viviparity);• development of unattached embryos within the uterus,

with energy supplied by large egg yolks ( ovo viviparity ); ingestion of infertile eggs (oophagy) and, very rarely, smaller embryos (embryophagy); or fluids secreted by the uterus; or

• development of the young within large leathery egg cases tha t are laid and continue to develop and hatch outside the female (oviparity).Depending on the species, female sharks may bear

from one to, exceptionally, as m any as 300 young (in the case of the whale shark Rhincodon typus, Chang et al.1997). Litter num ber in m ost species, however, falls within the range of two to 20 pups. Gestation perio ds are unknown for m ost species, but range from less than three m onths to as long as 24 m onths for the ovoviviparous spiny dogfish Squalus acanthias ( Com pagno 1984,Nammacke?a/. 1985; the longest gesta tion period know n fo r any living vertebrate); m ost are around 10-12 m onths. Breeding does not always occur annually in females; not only may gestation exceed 12 m onths, but some species have at least one ‘resting’ year between pregnancies (Branstetter 1990, 1997, P ra tt and Casey 1990).

Following this high initial investment in the pro duction of large eggs or pups, m any chondrichthyan fishes give birth in sheltered coastal or estuarine nursery grounds (M usick and Colvocoresses 1988, Castro 1993), where predation risks to the pups (primarily from other sharks) are reduced (Branstetter 1990), or deposit their eggs in locations where they are m ost likely to survive undam aged until the pups emerge. There is no know n post-birth parental care.

2.3 Life history constraints on exploitationThe life history strategies of elasmobranchs have developed over some 400 million years and are appropriate and successful for an environm ent where the m ain natural predators of these fishes are larger sharks. Such a K- selected life history strategy, however, poses limits on reproductive productivity and the ability of populations

to sustain fisheries and recover from depletion caused by hum an exploitation or other impacts ( Hoenig and G ruber 1990). In addition, the tendency of many chondrichthyan species to aggregate by age, sex and reproductive stage can make them particularly vulnerable to fisheries.

In comparing life histories across a num ber of vertebrate taxa (Table 1 ), it is immediately apparent tha t sharks are am ong the latest-m aturing and slowest-reproducing of v erteb ra tes . T heir rep ro d u ctiv e stra teg ies co n tra s t m arkedly with those employed by m ost teleosts (bony fishes ), which support mo st fisheries. Teleo st fishes produce thousands to tens of millions of tiny eggs annually and, a lthough only very few young survive to m aturity , recruitm ent to the adult population is broadly independent of the size of the spawning stock (until the latter declines to extremely low levels ). This is partly due to the operation of density-dependent factors tha t com pensate for adult p o p u la tio n decline. A lm ost all trad itio n a l fisheries m anagem ent is based on these typical teleost life history strategies (H illborn and W alters 1992).

In contrast to teleosts, the recruitm ent of sharks to the adult population is very closely linked to the num ber of m ature, breeding females (Holden 1974), although some d ensity -dependen t fac to rs (for exam ple, im proved survivorship of small elasmobranchs in the absence of large adult sharks) may also operate for their stocks (Musick et al. 1993, van der Eist 1979). The result is that, as m ature animals are caught, the production of offspring that will support future generations also declines, which in turn limits future productivity of the fishery and the ability of elasm obranch populations to recover from overfishing. In this respect, the reproductive potential and strategies of the chondrichthyans are more closely related to those of the cetaceans, sea turtles, large land mammals and birds than to the teleost fishes (Table 1). Therefore, a very different management regime to that employed for teleosts is required to prevent the overexploitation of elasmobranchs and sustain fisheries over a long period of time.

A lthough the large m ajority of chondrichthyan species is slow-growing with low reproductive potential (see Table 1), a few sharks and rays, especially some smaller species, are not as extreme in their life histories. For example, the A ustralian sharpnose shark Rhizoprionodon taylori matures at an age of one year, lives to an age of six or seven years, and has a natural m ortality coefficient of about 0.56 (Simpfendorfer in press a). This means that, on average, 56% of each age-class in the population dies every year from natural causes ( predation, disease etc. ) and only 44% survive. By contrast, an average natural m ortality coefficient for the very slow-growing sandbar shark is c. 0.10-0.05, or 90%—95% survival (Sminkey and Musick 1996).

In general, smaller-sized elasm obranch species have a tendency to m ature earlier, be shorter-lived, and have higher rates of population increase. M any dogfishes,

4

Table 1. Comparative life-history traits of sharks with other long-lived and/or wide-ranging taxa.

Scientific and common names

Age to m aturity (years)

Size (cm) (total length maximum or at maturity)

Life span (years)

Littersize

Annual rate of

population increase

Reproductiveperiodicity

(years)

Gestationtime

(months)

CITES listing

(Appendix I, II, III)

Carcharhinus plumbeus Sandbar shark1

13-16 (29 in

another study)

M: 170 (mat), F:>180 (mat),

-235 max (in US)

35 8-13 pups 2 .5 % -1 1.9% (5.2% if

maturity is 29 years)

2 9-12 none

Prionace glauca Blue shark1

M: 4-6 F: 5-7

M: 182 (mat), F: 221 (mat);

383 (max)

20 40 pups; 135 max.

6.25% females?males

annually?

9-12 none

Squalus acanthias Spiny or piked dogfish or spurdog1(NW Atlantic population)

M: 6 F: 12

M: 60 (mat), 100 (max); F: 70 (mat), 124 (max)

M: 35 F: 40

(70: NW Pacific)

2 -15 pups 2.3% 2 (but no resting stage)

22-24 none

Thunnus m acocyii Southern bluefin tuna2

10-11 225 (max TL)

40 14-15 million eggs

? annual n/a none

Xiphias gladius Swordfish3 (N. Atlantic)

M: 1-5 F: 5-9

M :165 FL F: 209 FL

25(max)

1-9 million eggs/batch

4.3% annual n/a none

Gadus morhua Atlantic cod4 (New England stock)

2 -4 32-41 (mat), 130 (max)

20+ 2-11 million eggs

? annual n/a none

Paralichthys dentatus Summer flounder4

1 27 (at mat) F: 20 M: 7

0 .5-5 million eggs

50% annual n/a none

Tursiops truncatus Bottlenose dolphin5

M: 11 F: 12

M: 381 F: 367

50 (min) 1 ? 3-6 12 I (lactation 12-18)

Balaenoptera musculus Blue whale6 (Antarctic)

5 3,100 (max) 110 (max) 1 5.1 %(N. Atlantic)

2 -3 11 I

Caretta caretta Loggerhead sea turtle7

12-30 92-122 -50+ 116eggs/clutch

76.5/year

2 % -6 % 2 -5 in SE US n/a I

Panthera tigris Asian tiger8

3 -7 140-280 (w/o tail)

26 1-7 per litter

? 2 -3 3.3 I

Toxodonta africana African elephant9

8-13 M :320-401 F: 220-260

(shoulder ht.)

55-60 1 4% -7%(favourableconditions)

2.5-9 22 I/ll

Dromedea epomophora Royal albatross10

6-11 122 (max) 58-80 1/clutch ? 2 n/a

References:1 See A nnex 1 ; 2 'A rocha 1997, Hoey e ta /. 1990, ICCAT 1996; ‘ National Marine Fisheries Service 1 99 5 ;5 Kllnowska and Cooke 1991 ; 'B es t 1993, Laurie 1937, Lockyer 1984, Ohsuml 1979; TCamhl 1993, Crouse et al. 1987, Frazer and Ehrhart 1985, R ichardson and Richardson 1982; 'N ow e ll and Jackson 1996; ’ Laursen and Bekoff 1978; 10Gales 1993.

particularly deepwater species, are an exception to this rule (W alker 1998a). Species with the highest capacity to rebound from overexploitation tend to be the smaller, inshore species, which have evolved shorter generation times as an adaptation to higher rates of predation ( Smith et al. in press). These species may be able to sustain com m ercial fisheries w ith careful conservation and m anagement. For example, the gummy shark Mustelus antarcticus in southern Australia, which reaches m aturity

at 4-5 years o f age ( for females ) and a maximum age of 16, has sustained a carefully m anaged fishery for m ore than 25 years (W alker 1996 and in press).

In contrast, larger, longer-lived species have less capacity to sustain exploitation or recover from depletion (Smith et al. in press). Fisheries for these species, such as sandbar, dusky and leopard sharks, and deepwater sharks with exceptionally low metabolic rates, require even more cautious m anagem ent if they are to be sustained.

5

Chapter 3

Overview of Exploitation and Other Threats

3.1 FisheriesC hondrich thyans are exploited for their m eat, fins, cartilage, leather, oil, teeth, gili rakers and jaw s (Rose1996). They are directly targeted in some com m ercial and recreational fisheries and are caught incidentally as bycatch in m any o ther fisheries (A nderson 1990a, Bonfil 1994). W hile fisheries are the m ajor fac to r affecting shark populations, beach netting and drum lining for swim m er p ro tec tion m ay also lead to shark m ortality (1,000 to 1,500 large sharks per annum) in localised areas of S outh A frica and A ustralia (Paterson 1990, C liff and D udley 1992, K rough 1994, M cPherson et al.1998), or c. 2,500-3,000 sharks annually , worldwide.

A lthough sharks are the m ost widely recognised group o f the chondrich thyans taken in fisheries and entering in te rna tiona l trad e (particu larly their fins), th e t r a d e a n d p o p u la t io n s ta tu s o f th e o th e r chondrich thyans, particu larly the bato ids (skates and rays), is also of considerable concern. F rom the fisheries d a ta re p o rte d to the U N F o o d and A g ricu ltu re O rganization (FA O ) over the last 15 years, sharks com prised 60% o f the w orld chondrich thyan catch, and skates and rays com prised alm ost 40% (Bonfil 1994). There are only a few target or utilised bycatch fisheries fo r chim aeras, m ainly in the sou thern hem isphere: N ew Z ealand , A u stra lia , S ou th A frica and S ou th Am erica (D idier in press), com prising ab o u t 0.7% of chondrich thyan fish catches reported to FA O . This section , th ere fo re , p rim arily covers e la sm o b ran ch exploitation .

FA O has published a com prehensive overview of w orld elasm obranch fisheries, including regional trends in landings and bycatch, pa tterns o f explo ita tion , and an appraisal o f their problem s and m anagem ent needs (Bonfil 1994). This rep o rt docum ents how grow th in shark fisheries in the past was lim ited by their low econom ic value and relatively low abundance. Y et there has been steady grow th in shark fisheries since W orld W ar II, the result o f an overall in tensification of m arine fisheries and increasing hum an popu lations worldwide. M ost recently, the grow ing dem and for shark fins ( and, to a lesser extent, m eat) has fu rther stim ulated shark fisheries in some p arts o f the w orld (e.g. USA, C entral A m erica, and Indonesia, as no ted by T R A F F IC in R ose (1996 and 1998), C hen 1996, and Phipps 1996). N onetheless, com m ercial catches o f chondrich thyans still com prise only abou t 1% o f the repo rted w orld fisheries catch.

It is im p o rtan t to no te th a t the upw ard trend in w orld e lasm obranch catches since the early 1980s repo rted by FA O does no t take increasing fishing e ffo rt in to acco u n t. A lso, the genera l p a tte rn o f declining elasm obranch landings in m any areas are m asked by increased landings from new ly-established elasm obranch fisheries elsewhere.

Bonfil (1994) reports tha t 26 m ajor fishing countries caught m ore than 10,000 metric tonnes (t) per year of elasm obranchs. His m inim um estim ate of the world commercial elasm obranch catch in 1991 was 714,000 t, representing approxim ately 71 million animals. This figure significantly underestim ates the actual annual catch because FAO statistics do no t include recreational or incidental catches and discards, and many landings are under-reported. Therefore, Bonfil (1994) concludes tha t the to tal level of world elasm obranch catches in 1991 may have been twice the official statistic, or nearly 1,350,0001. Close m onitoring of catches in selected countries would help to verify such estimates.

D ata on the utilisation of shark landings are poor because m ost countries do not report statistics on shark products or local consum ption. Fresh shark m eat is consumed locally in m any parts o f the world, but, because some shark meat is difficult to process due to its high urea content (which taints the flesh if not bled, rinsed and chilled quickly ), it has been of low value for export markets. In contrast, dried shark fins (used for shark fin soup) and dried shark m eat are easy to process and supply to distant m arkets. In the mid-1980s, a surge in dem and for shark fins in Asia caused a rapid increase in fin prices. A lthough data on the fin trade are substantially incomplete because m any countries do not report fin exports, trade in fins certainly increased dram atically in the 1980s (Rose 1996, 1998, Chen 1996, Phipps 1996, Chen et al. 1996, Sant and Hayes 1996, Fleming and Papageorgiou 1997, Hanfee 1997, and M arshall and Barnett 1997).

The continuing emphasis on elasm obranch fisheries appears to be the result o f several factors, including:• the increased world dem and for fish protein;• a related rise in shark exploitation (target and bycatch )

to replace declining catches from many depleted teleost stocks (as reported in FAO statistics); and

• the rising dem and for and value of shark fins in international trade.

Certainly, FA O reports th a t world elasm obranch landings have been stable in the 1990s, while many teleost fish catches have been level or declining and some

6

established shark fisheries have undergone declines. This continued or increasing exploitation is exceeding the cap ac ity o f som e sh a rk p o p u la tio n s , re su ltin g in documented stock depletions where data exist (Musick 1995, N O A A 1998a), and presum ably also in regions where fisheries are not m onitored.

As close relatives to the sharks, the batoid fishes (skates, rays, and sawfishes) have very similar life history characteristics and hence vulnerability to overfishing. They are taken by directed and multi-species fisheries for their m eat ( highly valued in many areas ), represent a significant com ponent o f fisheries bycatch, and are also widely discarded.

The fins of guitarfishes and sawfishes and the wing tips of some rays are processed and traded as ‘shark fin’, with the form er two groups providing some of the m ost highly valued fins in the world. Some ray species are also utilised for their skin. The saws (rostra) of the rare sawfishes are also traded as curio items and for traditional Chinese medicine (in very small numbers, due to their increased rarity ). The gili rakers of plankton-feeding m anta rays and whale sharks are reported to be as valuable as whale shark fins. O ther ray species may be of low value, but are taken in large num bers as bycatch and often fully utilised in artisanal ‘catch-all’ fisheries.

U nfortunately, bato id fisheries and trade are even less effectively m onitored and reported than those for sharks, not least because of the difficulty of identifying a great m any species in the absence of an adequate identification guide and investment in taxonom ic research. Indeed, in some regions, such as South-east Asia, some of the common stingrays landed by fisheries have not been scientifically described or named (Fowler et al. in press a).

3.1.1 ‘Boom and bust’ and collapsed fisheries

There is a well-docum ented history o f shark stocks that have undergone a brief period of fisheries exploitation followed by a sudden collapse in yield. Often-cited examples of collapsed shark fisheries include the porbeagle Lamna nasus fishery in the N orth Atlantic, the soupfin shark Galeorhinus galeus fishery in California, various basking shark Cetorhinus maximus fisheries, and spiny dogfish Squalus acanthias fisheries both in the N orth Sea and off British Columbia ( e.g. Anderson 1990b ). Indeed, many of the unregulated target shark fisheries for which data exist have been ‘boom and bust’ endeavours. These are rem arkable for the relatively short period for which they ‘boom ’, which is followed by a very rapid decline in catches and a long period of either very slow recovery (usually only possible under fishery closure) or continued low yield at a small fraction of the original catches. Examples of a few such fisheries are provided below.

Norwegian porbeagle Lamna nasus fishery

A nnual Norw egian landings of porbeagle shark from the N orth-east A tlantic increased rapidly from 279 metric tonnes (t) in 1926 to a high of 3,884 t in 1933, then declined to 2,213 t in 1939. Catches were greatly reduced for five years during W orld W ar II when fishing effort was very low, presumably resulting in some stock recovery. The fishery resumed in 1945, reached a high of 2,824 t in 1947, then again began to decline. In 1961, the Norw egian fleet began to target the porbeagle stock in the N orth-w est A tlantic. Longline catches increased from 1,8241 in 1961, when catch per unit effort (CPUE) was 9.1 sharks per 100 hooks, to 8 ,0601 in 1964, bu t then declined to only 2 0 7 1, with a CPU E of 2.9 sharks per 100 hooks in 1968 (Gauld 1989). Total landings in N orw ay have no t exceeded 1001 since the late 1970s and averaged 331 per year in the decade ending in 1994. The fishery is now of little significance to the Norw egian fleet (Anon. 1995). This declining trend has been observed elsewhere in European waters.

M arket prices cannot explain these low landings; the porbeagle remains one of the highest-value food fishes landed in northern Europe and is still sought-after where it occurs. R ather, the decline can be attributed to the overfishing of a species which does not reach m aturity until over seven years of age (for females ), lives to 30 years, and produces between one and five pups per litter (see A nnex 1).

California soupfin Galeorhinus galeus fishery

California shark landings during 1930-1936, o f which soupfin Galeorhinus galeus comprised a high proportion, were relatively low and stable a t c. 270 t/year. Following the establishm ent of a new m arket for liver oil in 1937 the fishery expanded enormously, with catches peaking at 4,185 t in 1939. Prices rose from some $50/t in 1937 to $2,000/t in 1941. Soupfin landings (identified separately from 1941 onwards) declined from 2,172 t in 1941 to 287 t in 1944. CPU E in one region declined from 55.4 fish/1,000 fathom s of gillnet fished for 20 hours in 1942 to 7.7 fish from the same fishing effort in 1945 (Roedel and Ripley 1950). This trend was probably indicative of the whole US west coast (Leet et al. 1992).

M ore than 50 years later, it is uncertain whether the soupfin stock has recovered; there are no fisheries specifically ta rg e tin g the species, and catches are fluctuating. A lthough the fishery was intensive and expanded rapidly, it spanned only eight years. Similar landings over a similar period have occurred in New Zealand and A ustralia w ithout causing the collapse of the fishery, but m anagem ent was introduced in the 1980s to reduce effort and reverse declining trends ( Stevens in press d). Since soupfin sharks were targeted by the fishery at a relatively large size in California (their longevity is 60

7

years), and since small juveniles were essentially unfished and would take several years to recruit to the fishery (females m ature at 10-15 years of age), in the absence of other negative factors the stock would have been expected to rebuild once fishing ceased. Soupfin sharks are, however, dependent on pupping and nursery grounds, often in sheltered inshore areas. D eterioration and/or loss of this hab ita t could be a factor contributing to delayed recovery for this stock and in other populations (Stevens in press d).

Basking shark Cetorhinus maximus fisheries

There are several examples of collapsed fisheries for the basking shark. Inform ation about the life-cycle of this species is scarce, but females may no t reach m aturity until 18-20 years of age and live to perhaps 50 years (Pauly 1978). (Parker and S to tt’s (1965) estimates of m aturity at 4-5 years following grow th rates of about 1 m/year from perhaps 1.7 m to tal length at birth are no longer widely accepted. ) Basking sharks probably do not pup every year and the only know n litter consisted of just five very large young (Sund 1943).

The oldest fishery records for this species are from the Sunfish Bank, west Ireland, in the late 18th century. Probably due to its artisanal nature, this fishery spanned several decades. Rising demand for shark liver oil, however, led to serious declines by 1830 and fishery collapse in the second half of the 19th century. Basking sharks were not targeted actively again off west Ireland until 1947, when a new, very localised fishery started at nearby Achill Island. Between 900 and 1,800 sharks were taken each year from 1950 to 1956, with a significant decline in catch records occurring from 1955 onward. Average annual catches declined from 1,067 per year in 1949-58, to 119 p e ry ea rin 1959-68, and then 40 per year for the rem aining seven years of the fishery. Even increasing shark oil prices and capital investment during the last few years of the fishery did no t reverse the steady decline in catches, and the fishery ended in 1975. A to tal of 12,360 individual fish had been taken in 29 years, with 10,676 of these caught in the ten peak years of the fishery starting in 1949 (M cNally 1976). Basking sharks are still only rarely sighted in the area today (Berrow and H eardm an 1994).

A Norw egian fleet was also fishing basking sharks over a large area of the N orth-w est A tlantic during the same period. Catches were high (>1,000 sharks and up to >4,000 in some years) between 1959 and 1980. Landings subsequently declined and have not exceeded 1,000 sharks peryear since 1981 (Kunzlik 1988).This collapse has been attributed to an ageing fleet and a decline in value of basking shark liver oil, but because the precise location from which the fish were taken is uncertain (data reflect a large sea area), it is difficult to detect and evaluate trends in catches. The fishery is still profitable only as a result of

the very high prices paid for the huge fins, now am ong the m ost valuable sold in Singapore.

A num ber of other small-scale fisheries for the basking shark have taken place. There is, however, generally insufficient inform ation on catches (hundreds ra ther than thousands of animals), trends in CPUE, and changes in frequency of bask ing shark sightings to determ ine population declines resulting from these fisheries. An exception is the 1950s basking shark eradication program implemented in Barkley Sound, Vancouver Island (aimed at preventing damage to salmon nets). The C anadian D epartm ent of Fisheries and Oceans had killed several hundred sharks by 1959 (Clemens and W ilby 1961) and appears to have removed the m ajority of the population; the species is still only rarely sighted, some 35-40 years later (Darling and Keogh 1994).

3.1.2 Future trends in fisheries

Despite the static or declining trend in fisheries landings identified by FAO in m ost parts of the world, an increasing dem and for fish products will likely lead to continuous increases in already heavily subsidised fishing activity. The record of ‘boom and bust’ shark fisheries described above suggests th a t the m ost recent increase in shark landings, m ost of which result from unm anaged fisheries, is unlikely to be sustainable beyond the next few decades. Similar patterns of declining landings are seen in some skate and ray fisheries for which adequate data exist (e.g. W alker and Heessen 1996, W alkerand Hislop 1998, Dulvy et al. in prep.).

One anticipated result o f the present and expected declines in tra d itio n a l fisheries yields will be the development of pioneer fisheries to exploit previously unfished popu la tio n s and species, a lm ost certa in ly including sharks, rays and chimaeras. This trend is already apparent for deepwater fisheries, now explored in many regions worldwide. N early 35% of chondrichthyan species are confined to deep water and will likely be affected by these new fisheries. Deepwater fisheries are generally conducted by very large, m odern vessels from m ajor industrialised fishing nations and supply international trade as well as domestic m arkets. They take place mainly in international waters, off the continental shelf, or around oceanic islands.

There is well-founded concern tha t deepwater sharks, adapted to a very stable environm ent of low productivity in com parison with the shelf seas, are less able to w ithstand commercial fisheries than the sharks and rays tha t have up to now supported pelagic and demersal elasm obranch fisheries. The biology of these deepwater species has been poorly studied, bu t they are believed to be very slow- growing, even in com parison with other elasmobranchs. M etabolic rates of some deep-sea teleosts have been

calculated to be only 10% of their coastal counterparts (Smith 1978, Smith and Brown 1983). Since the deep-sea shark fauna is dom inated by squaloids related to the coastal spiny dogfish Squalus acanthias, their intrinsic rates of population increase m ust be near the lowest o f any known vertebrate (that for the spiny dogfish is only 2% - 3% per year - see Table 1 - which means tha t the num ber of dogfish in the population can only rise by 2%-3% each year). Additionally, there is no inform ation about stock size or d istribu tion of these species. In some cases, deepwater fisheries are taking chondrichthyan species tha t have no t yet been described.

N o t only does a lack of biological inform ation ham per management of these fisheries, but politicians and managers have little or no incentive to regulate their country’s activities when these fisheries occur largely outside national waters. Indeed, in ternational fisheries policy remains inadequate even for teleost species and few marine animals have lower international fisheries m anagem ent priority than the unfam iliar, relatively low value, deepw ater chondrichthyans.

Some small and/or unusual elasm obranchs are being increasingly targeted for the public and private aquarium trade. This is o f particular concern for species with restricted distributions and small population numbers, suchas small freshwater rays, endemic species, possibly sawfishes, and other rarities. As dem and for the exotic fish trade (both by hobbyists and public aquaria ) increases in the years ahead, it is im portant that vulnerable populations of elasmobranchs should not be overexploited. The educational value of elasm obranchs in public aquaria, however, can be crucial to changing negative public perception of sharks, thereby building political will to conserve them. Certainly, though, capture for display should no t be allowed to threaten species survival in the wild.

3.2 BycatchElasmobranchs are caught incidentally, as bycatch, in most fisheries world-wide. The extent of bycatch and discards, both in domestic fisheries and on the high seas, is poorly documented (Alverson et al. 1994). While some elasmobranchs are landed and reported in official statistics, a large proportion is estimated to be discarded unreported. M ortality of incidentally caught sharks and rays is believed to be significant, especially from trawl nets, gillnets, purse seines, and longlines, and may exceed m ortality from directed fisheries (Bonfil 1994). Some fisheries for oceanic teleost species (tuna and billfishes) catch more sharks as bycatch than they do target species (e.g. Francis and Griggs1997). In addition, an increase in fin prices has encouraged the practice of ‘finning’ sharks th a t were previously discarded intact or released alive. Fins are easily air-dried and stored, whereas retention of whole shark carcasses

would compete for freezer space with more valuable species like tuna (Rose 1996, Sant and Hayes 1996). Finned sharks tossed overboard invariably die.

M ost countries do not require reporting of shark bycatch in fishing logbooks; therefore, few bycatch data are incorporated into national and international (e.g. FAO) statistics. A lthough observer program m es provide the best available inform ation, observer coverage of high seas fisheries is minimal. Virtually any species o f shark taken as bycatch in multi-species fisheries may enter regional or international trade, but there is very little tracking of this trade, particularly tha t resulting from artisanal fisheries. R are species of elasm obranchs taken as bycatch and entering trade (e.g. sawfishes ) are of particular concern.

A lthough there are m any gaps in available bycatch data, Bonfil (1994) estim ated that, at the end of the 1980s, approxim ately 12 million elasm obranchs (up to 300,000 t) were taken as bycatch each year on the high seas alone. A bout 4 million were taken in driftnet fisheries and more than 8 million on longlines (mainly in the tuna fisheries of Japan, Korea, and Taiwan). The species com position of these catches is virtually unknown, other than tha t m ost were sharks. Still, with an estim ated nearly 6.5 million individuals caught incidentally each year, the blue shark Prionace glauca is believed to be the m ost com m on species of elasm obranch in high-seas fisheries bycatch (Bonfil1994). A lthough m ost high seas d rift net fisheries ceased at the end of 1992, fishing effort has been redirected tow ards longlining, which also affects elasm obranch populations.

Batoids and small coastal shark populations are seriously affected by bycatch in bottom trawl fisheries. These impacts are rarely m onitored bu t are thought to be significant locally, particularly for regional endemics (Casey and Myers 1998, Dulvy etal. inp rep .,N otarbarto lo di Sciara in press). In some parts of the world, many inshore fisheries do no t intentionally target any particular group of species, bu t land and utilise everything they catch. In such cases, shark catches would not be considered incidental, but still may go unrecorded and will contribute significantly to the overall m ortality of the population.

3.3 Habitat loss and degradationAll chondrichthyan fishes depend on properly functioning ecosystems in order to sustain growth, reproduction and survival. H abita t requirements vary for different species during different stages of their lifecycles. Critical shark habitats range from shallow estuarine sloughs and coastal bays to coral reefs, kelp forests and the deep sea. As a result of their K-selected life history, sharks are generally unable to adap t to rapidly changing environm ental conditions. The use of inshore coastal nursery grounds, or

9

complete dependence throughout the lifecycle on coastal, estuarine, or freshwater habitats, has become a particular liability during the second half o f the 20th century as direct and indirect fishing pressures have intensified and coastal hab ita t loss and degradation have accelerated.

Adults of many shark species are know n to visit inshore pupping and nursery grounds on a seasonal basis, usually in the spring and summer (M usick and Colvocoresses 1988, Branstetter 1990, Castro 1993, Simpfendorfer and M ilward 1993). Newborns and juveniles may rem ain year- round in tropical waters, as these productive shallow areas provide both abundant food and shelter from predators (M orrissey and G ruber 1993). Less is know n about the location and characteristics of offshore over-wintering areas inhabited by many species of coastal sharks, both adults and juveniles, and of the offshore pupping grounds of pelagic sharks.

Coastal hab ita t is being destroyed and degraded at an alarm ing rate. H um an activity threatens coastal and estuarine habitats through development, fisheries activities, chemical and nutrient pollution, freshwater diversion from incoming rivers, and dum ping of plastic and other man- made garbage known to entangle and choke a wide variety of marine life.

In the United States, for example, hum an population grow th in coastal areas averages four times the national rate, and coastal hab ita t is being lost in direct proportion to population density. By the mid-1970s, over half of US m angrove stands and salt marshes had been destroyed. The state of California has lost over 90% of its coastal wetlands. Louisiana is losing 40 square miles of wetlands per year and precipitous declines in G ulf of Mexico fisheries are anticipated as a result. In Chesapeake Bay, the east coast’s largest estuary and a critical nursery area for coastal sharks and rays, increased algal growth and tu rb id ity from ag ric u ltu ra l ru n -o ff, sew age p la n t effluent and atm ospheric deposits led to a 90% loss of native bay grasses between 1950 and 1980 (H inm an and Safina 1992). Sim ilartrends are apparent inm ost countries.

Around the world, coral reef specialists report increased damage and serious global decline in this hab ita t over the past two decades. The W orld Resources Institute, the International Centre for Living M arine Aquatic Resources,

and the W orld Conservation M onitoring Centre report tha t 58% of the w orld’s reefs are at risk from hum an activities, with about 27% at high or very high risk. Reefs of South-east Asia, the m ost diverse in the world, were also the m ost threatened, with m ore than 80% at risk including 55% at high or very high risk (Bryant et al. 1998).

Scientists have just begun to study the effects of fishing on the marine environment. Recent research suggests tha t intensive bo ttom traw ling may reduce dem ersal fish productivity by reducing the complexity of the benthic substrate (Auster and Langton 1998, D ayton 1998). O ther studies are attem pting to quantify the im pact o f ‘ghost fishing’ from lost or abandoned fishing gear on fish populations.

Efforts to improve water quality and benthic complexity contribute to the protection of shark mating, pupping and n u rsery g ro u n d s. A d d itio n a l p ro te c tio n fo r shark populations may be gained by limiting fishing activity at times when sharks are aggregated in these areas or otherwise vulnerable to fishing. D em ographic models reveal tha t increasing the survivorship of juvenile sharks can yield great benefits in terms of population growth ( Cortés in press a).

As top m arine predators, long-lived elasm obranch species are significant bioaccum ulators of pollutants, more so than m ost other groups of marine organisms (W alker 1988b, F o rreste r et al. 1972). Indeed, adu lt sharks accum ulate such high levels o f m ercury th a t some A ustralian shark fisheries have maximum size limits on sharks landed for hum an consum ption - for example, the sale of sharks with a carcass weight of over 18 kg is prohibited in W estern Australia, and the South A ustralian shark fishery also limits landings of larger sharks.

O v e ra ll, d o c u m e n ta t io n o f h o w a lte re d an d contam inated habitats and bioaccum ulation of pollutants affect the health and productivity of sharks or the overall dynamics of the m arine food web remains scarce. Those species restricted to freshwater and estuarine habitats but with very small populations (for example, some sawfishes, the Borneo river shark and other large freshwater species) are likely to be the m ost vulnerable, although also some of the least-studied (Thorson 1982, Com pagno and Cook1995).

10

Chapter 4

Conservation Status

4.1 Extinction riskN o marine fish species is yet know n to have been driven to biological extinction by fishing (M usick 1998). Regional stocks of some species, however, have been extirpated (Brander 1981, Beverton 1990, Casey and Myers 1998, H untsm an in press ). Because of their life history strategies, m any sharks are highly vulnerable to over-exploitation leading to population depletion. Some are particularly susceptible to extinction asa result of these factors because

of their restricted distribution, small population sizes, or other characteristics, including dependence on nursery grounds or specific habitats, behaviour and m orphology. F o r example, all species of sawfishes Pristis spp. are considered to be threatened with extinction (Table 2), because they occupy restricted freshwater, estuarine or shallow inshore habitats tha t are subject to increasing hum an disturbance and exploitation, and are highly vulnerable to bycatch in fishing gear at all life stages. Their to o th ed ro s tru m (saw) m akes saw fishes extrem ely

Table 2. IUCN Red List assessments for elasmobranchs (updated from The 1996 Red List).

Common name Scientific name Stock Red List Assessment1B lun tnose s ixg ill H exanchus griseus W orld Low er risk, near th rea tened

W hale shark R h incodon typus W orld Data D efic ient

Sand tig e r shark C archarias taurus W orld SW A tlan tic Eastern A ustra lia

VU A la ,b, A2d EN A la ,b, A2d EN A la ,b, A2d

G reat w h ite C archarodon carcharias W orld VU A 1b ,c ,d , A 2c,d

Porbeagle Lam na nasus W orld NW A tlan tic NE A tlan tic

Low er risk, near th rea tened Low er risk, conse rva tion dependen t VU A 1b ,d , A2d

B asking shark C eto rh inus m axim us W orld VU A la ,d, A2d

B la ck tip shark C archarh inus lim ba tus W orld Low er risk, near th rea tened

D usky shark C archarh inus obscurus W orld NW A tlan tic

Low er risk, near th rea tened VU A id , A2d

S andba r shark C archarh inus p lu m b e u s W orld NW A tlan tic

Low er risk, near th rea tened Low er risk, conse rva tion dependen t

G anges shark G lyph is g a nge ticus W orld CR A 1c-e , A 2c-e , C 2b

Blue shark Prionace g lauca W orld Low er risk, near th rea tened

K itefin shark D alatias licha W orld Low er risk, near th rea tened

Freshw ater saw fish P ris tis m ic ro d o n W orld SE Asia

EN A la ,b ,c, A 2c,d CR A 1a,b ,c , A 2c,d

S m a lltoo th saw fish P ris tis pec tin a ta W orld NE A tlan tic SW A tlan tic

EN A la ,b ,c, A 2c,d CR A 1a ,b ,c , A 2c,d CR A 1a,b ,c , A 2c,d

Large too th saw fish P ris tis p e ro tte ti W orld CR A 1a,b ,c , A 2c,d

C om m on saw fish P ris tis p ris tis W orld EN A la ,b ,c, A 2c,d

Brazilian gu ita rfish R h inoba tos ho rke lii W orld CR A 1b ,d , A 2b ,d

Deepsea skate Bathyraja abyssico la W orld Data D efic ient

C om m on skate Raja ba tis W orld EN A1 b -d , A2 b -d

G iant freshw a te r s ting ray H im antura chaophraya W orldThailand

VU A 1b-e , A 2c,e CR A 1b-e , A 2c,e

1The ca tegories o f th rea t are: C R =critica lly endangered, EN=endangered, VU =vulnerable. See A nnex 2 fo r explanation.

11

vulnerable to entanglem ent in fishing gear at all ages, and very difficult to release alive even if not wanted in the catch (Com pagno and Cook 1995, in press d). The tendency of the white shark Carcharodon carcharias to investigate hum an activities makes it very easy to approach by trophy hunters (Fergusson et al. in press).

There is debate over the potential for fisheries ( or other factors) to drive wide-ranging marine fishes (both teleosts and chondrichthyans) to extinction (M usick 1998). Some argue tha t a species will become commercially extinct before going biologically extinct and, therefore, will be relieved of fishing pressure, which should allow the species to recover. It may be true tha t targeted fisheries will collapse of their own accord when stocks become so reduced tha t they are no longer profitable to pursue. However, the notion th a t a fish will reach economic extinction before biological extinction is no t certain in cases where the value of the product is so high th a t it is economical for fishers to continue to pursue an extremely small surviving stock, or where economic yields are not a controlling issue (e.g. for recreational trophy fishing). Similarly, in a mixed-species fishery where all species are subject to the same fishing effort and similar fishing m ortality rates, less abundant species subjected to fishing activity th ro u g h o u t their range could be driven to extinction, while numerically dom inant species continue to support the fishery (M usick 1995). Species caught extensively as bycatch may be, indirectly, even more vulnerable than target species taken in a mixed fishery, because discards and landings are generally poorly m onitored and signs of declining catches and collapsing stocks may thus be overlooked. Such was the case for the N orth-w est A tlantic barndoor skate Raja laevis, a large, late-m aturing species taken as bycatch in the bottom trawl groundfish fishery. Casey and Myers (1998) found tha t R. laevis appears to have become extinct in northern C anadian waters and currently survives only in small num bers off Georges Bank at the southern edge of its range (where warmer water tem perature allows faster grow th and presum ably earlier m aturity).

C osm opolitan and wide-ranging species may become locally depleted in some parts of their ranges even as their global abundance remains high. It is difficult, however, to assess the cumulative effect of localised depletions on the viability of a species at a global level, as unregulated and unm onitored shark fisheries crop up around the w orld . Som e argue th a t im m igra tion from source populations will offset these depletions, thereby reducing extinction risk, but very little is know n about population dynamics and structure or m igratory behaviour in m ost chondrichthyans.

The assum ption that marine fish populations are not vulnerable to extinction because they are ‘open’ with large geographic ranges and unlimited immigration is unfounded. Coastal stocks of even large m igratory species such as

sandbar sharks have discrete geographic boundaries ( Musick 1995 ). Catch per unit effort ( CPUE ) data from some beach- netting programmes and historic examples of collapsed stocks, such as N orth A tlantic porbeagle sharks Lamna nasus, suggest that migration between stocks, or even within a single stock ( where individual fish tend to return seasonally to the same coastal area throughout their life), may be limited. Overfishing of the large and long-lived common skate Raja batis this century has led to its extinction in the Irish Sea ( Brander 1981) and m ost of the N orth Sea ( see case study below). The fact tha t the common skate still occurs in the nearby waters of the Celtic Sea and N orth-east Atlantic, but is not recorded in landings from the former areas, suggests that recovery of depleted or extirpated populations through local immigration is not guaranteed, or would be extremely slow, even if all skate landings ceased.

Similarly, even if the North-w est Atlantic shark fishery were completely closed, stock recovery of the sandbar shark Carcharhinus plumbeus and other large coastal species in the region would take several decades because of the very low rate of population increase for the species ( see T able 1 ).

In general, the rate of recovery of an elasm obranch populationfollow inglocalised depletionis species-specific. It will depend not only on the species’ reproductive capacity, bu t also on m igration patterns, the level of depletion, the rate of population increase (taking into account possible density-dependent factors), and changes in habita t and prey population structure.

The biological vulnerability of m ost chondrichthyans suggests tha t extinction resulting from fisheries is possible. F or targeted species, this risk is largely dependent on m arket forces and the economics of the fishery. This is not necessarily the case for bycatch species, regardless of their economic value; their extinction risk will be related to overall fisheries effort and will increase if the species has a restricted range or other specialised ecological requirements. It is notew orthy that commercial whaling extirpated all but a few individuals o f some regional whale stocks, and that these are still threatened with extinction despite a cessation in whaling activity m any decades ago. Given tha t there are greater life history similarities between sharks and marine mammals than between sharks and most teleost fishes (Musick 1997), such a scenario is also possible for some shark populations.

Finally, biological extinction is a process tha t can have detrim ental and irreversible ecological effects long before a species disappears. If a species’ abundance drops too low, it may no longer perform its function as predator or prey in the eco system -a situation often referred to a s ‘ecological extinction’. It is unclear w hat effect the large-scale removal of sharks may have on the food webs of marine communities. O ff south-eastern Africa and in the N orth-w est Atlantic, however, heavy fishing of large sharks may have resulted in the proliferation of smaller sharks, skates and rays ( van der Eist 1979, M usick et al. 1993).

12

Because intensive target and indirect fisheries for elasm obranchs have only started during the present life span of long-lived m ature sharks, the effect o f a very large decline in species abundance on extinction risk or other impacts on populations and marine communities is still largely unknown.

4.2 IUCN Red List assessments for sharksA lthough the subject of extinction risk in marine fishes is not new, only recently have attem pts been made to evaluate it. The Shark Specialist G roup (SSG) is now systematically assessing the global conservation status of the chondrichthyan fishes using the revised IU C N Red List Categories and Criteria, summarised in Annex 2. These criteria endeavour to provide a more objective assessment of a species’ extinction risk. They have, for the first time, enabled a wide range of m arine fish species to be classified in the IU C N threatened species categories, largely on the basis o f estimates o f recent and projected population declines (criterion A, see Annex 2).

These efforts have pointed to a problem with the use of the population decline criterion; it can lead to a significant over-estimate of extinction risk in the case of widely distributed species, or those with highreproductive potential or fecundity. This is particularly true for a species with a very high initial abundance; a very large population decline (50% or 80%) does not necessarily equate to the very high extinction risk implied by the Endangered or Critically Endangered IU C N Categories (Fowler 1996a, in press a, Musick 1998). The IU C N Criteria are currently under revision to address this and other issues.

The SSG has identified an initial list of over 100 species of elasmobranchs, some of which may be threatened by exploitation or habita t loss, and is in the process of evaluating their extinction risk using the IU C N Criteria, while taking into account the above drawback in the Criteria and adjusting the evaluated extinction risk accordingly. The resulting assessments will be published in forthcoming IU C N publications ( including Fowler et al. in press b and the IU C N Red List). The remaining species are still to be evaluated, but it is expected that additional at-risk species will be identified as more species-specific information becomes available.

It should be noted that, for m ost species, there is a significant lack of baseline data on historic stock sizes, as well as current abundances or changes in catch per unit effort, to use asa basis for these assessments. In such cases, it has been necessary to extrapolate from the biological inform ation available for other, closely related species, or from w hat is know n of overall fisheries trends in a region.

The results o f the Shark Specialist G ro u p ’s 1996 threatened species assessments for chondrichthyan fishes

are presented in Table 2. ( This is updated from the published IU C N Red List (IU C N 1996) and should be read in co n ju n c tio n w ith the sum m arised IU C N R ed L ist Categories and Criteria presented in Annex 2.) M ost of these classifications result from application of Red List C riterion A, which is a measure of decline in num bers of m ature individuals in the population calculated over the past three generations or projected into the future for the next three generations. Because m ost chondrichthyans are relatively long-lived, with generation times of often more than a decade long (see Annex 1 ), the period over which the decline in population m ust be considered will m ost often be 30 years or longer.

4.3 Species case studiesBrief species conservation status accounts for a few examples of elasm obranchs are presented below. These animals were selected to illustrate some characteristic aspects of the life history, hab ita t requirements, and biological status of chondrichthyans th a t make them particularly vulnerable to over-exploitation. The following accounts are summarised from much longer species reports in the IU C N Status R eport (Fowler et al. in press b).

Two examples of carcharhinids are presented: the sandbar shark Carcharhinus plumbeus, a wide-ranging, very slow-growing, well-studied coastal species, im portant in directed fisheries, bu t seriously depleted in the US Atlantic; and the blue shark Prionace glauca, an abundant and relatively fecund, cosm opolitan, oceanic species that is subjected to extremely high fishing pressure as bycatch in high-seas fisheries.

The soupfin or school shark Galeorhinus galeus is a species with a long history of exploitation: one population has collapsed while a separate, steadily fished population is recently showing signs of depletion. Despite its rarity, the white shark Carcharodon carcharias is an im portant marine m acro-predator. A lthough it has protected status in parts of its range, the white shark is still threatened by m ortality from bycatch, sports angling, and some other directed fisheries for its jaws, teeth and fins.

The kitefin shark Dalatias licha is an example of the ra th e r poorly know n deepw ater species. D eepw ater chondrichthyans have been subject only to relatively small- scale directed fisheries, bu t are now likely to come under increased fishing pressure as traditional fisheries decline.

Examples of three batoid fishes (skates and rays) are included. A lthough not ‘tru e’ sharks, many batoids are also im portant in fisheries and international trade and are equally vulnerable to over-exploitation. They are primarily taken for their meat, which is highly valued for hum an consum ption in m any regions, bu t the wingtips of some rays may also be dried and sold as ‘shark fin’. Their skin is sometimes used for leather. M ost batoids are strongly

13

K-selected species, and overfishing can severely deplete populations, if not regionally extirpate or threaten some species with extinction.

Sawfishes (family Pristidae) are dependent on very restricted coastal, freshw ater, and inshore/estuarine habitats and are now very scarce as a result o f fishing pressure (they are extremely vulnerable to bycatch in nets), bu t still highly valued in the international trade for shark fin, curios and traditional Chinese medicine.

The Brazilian guitarfish Rhinobatos horkelii has a restric ted geograph ic range, being endem ic to the continental shelf of the south-western A tlantic Ocean. Its entire range is very heavily fished, particularly those areas used by pregnant females and juveniles. As a result, the species has suffered a severe population depletion over the past decade. The giant or ‘com m on’ skate Raja batis was form erly an im p o rtan t com ponent of the N o rth e rn European catch, but is now extirpated from or very rare in m ost of its form er centres of abundance.

4.3.1 Status of the sandbar shark Carcharhinus plumbeus (Nardo, 1827)

The sandbar shark Carcharhinus plumbeus, a medium-to- large-sized shark reaching a maximum reported size of c. 230 cm to tal length (TL), is a wide-ranging coastal species typical of other com m on coastal sharks in many aspects of its biology. It is characteristic of the requiem sharks ( Carcharhinidae), which are subject to fisheries worldwide because of their wide distribution and im portance for hum an consum ption (they have good-quality flesh and valuable ‘w hite’ fins th a t fetch a prem ium price in international trade). The history of the fishery in the N orth-w est A tlantic (described below) illustrates how high catches can continue for a decade or more when the original stock is very large, even when the stock has declined drastically and recru itm ent is slow. If left unchecked, however, such overexploitation willeventually cause a population crash, with very slow subsequent recovery.

The sandbar shark is the m ost abundant large coastal shark in the western N orth A tlantic and eastern G ulf of Mexico. The species exhibits strong seasonal movements in this region, with segregation of adult males and females, neonates and juveniles in different geographic areas and habitats. A dult female sandbar sharks use temperate, estuarine waters as pupping grounds in summer, where neonates and juveniles (age 1-4 years) are also found. Larger juveniles use shallow coastal habitats and adult females move offshore immediately after pupping. Sandbar sharks of all ages migrate south to warm er waters in winter. In contrast, island populations, such as those in Hawaii, appear to be seasonally resident.

Sandbar sharks are K-selected species. They grow very slowly and m ature at a relatively late age (calculations

range from 13-16 to 29 years, and 150 to 180 cm). These sharks are viviparous with a yolk sac placenta. Gestation has been estimated at 9-12 months, with females breeding only every other year. Litter size is variable (1-14) and depends in part on the size of the mother, but averages 5.5- 9.3. The size of newborn pups averages 60-65 cm TL in m ost areas.

Sandbar sharks feature prom inently in coastal shark fisheries worldwide. Along the US A tlantic coast, this species comprises up to 60% of the total shark catch and 80% of the landings in the directed longline fishery. In addition, it is second only to the blue shark in importance in the US Atlantic recreational shark fishery. During the last 20 years, the recreational and commercial fisheries for sharks along the west A tlantic Coast and in the G ulf of Mexico have expanded rapidly, with commercial landings rising dramatically between 1985 and the implementation of a Lisheries M anagem ent Plan (LMP) in 1993. Sandbar shark stocks in the western A tlantic were reduced by 85%- 90% in just ten years as a result o f overfishing. In addition, the age structure of the population has shifted dramatically tow ard younger age classes; adult females are now only very rarely observed. The species continues to support a substantial fishery after this severe population decline only because of the very large size of the original stock and recently implemented conservative landings quota. H abitat degradation in nursery areas is also a th rea t to the recruitm ent of this species.

A lthough the US fishery is now regulated under the LM P, there was concern tha t m anagers had considerably under-estim ated the extent of stock depletion and used an unrealistically high annual rate of replacem ent (r) based on a model more appropriate for fast-growing teleost fishes. In 1996, an L M P Scientific R eview Panel recommended tha t the to tal allowable catch (TA C ) should be significantly reduced or the fishery closed to enable recovery. U nder the LM P, the target fishery m ortality (F = 0.25) could only lead to continued population decline. Consequently the TAC was reduced by 50% in 1997. F urther reductions and size restrictions have since been proposed to enhance the chances for population recovery. Even if the fishery were completely closed, the population dynamics of these sharks is such tha t stock recovery of the sandbar shark and other large coastal species in the N o rth ­west A tlantic could take several decades.

This species has been classified globally as “Lower Risk, near threatened” according to the IU C N Red List C riteria. This assessment takes into account the very wide- ranging nature of the world population of this species, the history of the N orth-w est A tlantic fishery described above, the high value of the species in fisheries and trade, and the strong likelihood tha t similar trends exist or will occur in other regions (where there is no fisheries management) w ithin the next 60 years (the three-generation period for this species). These factors are tempered by the lack of

14

data on populations and past and projected catches from other regions. The US A tlantic and G ulf of Mexico stocks, which are well studied, were considered to be “Vulnerable (A lb ,d , A 2d)” in 1996, but have now been reassessed as “Lower Risk - conservation dependent” .

[Summarised from M usick 1995 and in press.]

4.3.2 Status of the blue shark Prionace glauca (Linnaeus, 1758)

The blue shark Prionace glauca is a member of the requiem shark family, Carcharhinidae. It is representative of the oceanic (pelagic) sharks tha t are com m on in the w orld’s oceans and subject to an extremely high level o f bycatch in high-seas longline and driftnet fisheries for other species. Because it is no t a valued fishery species, the bodies (with low-value meat) are usually discarded but the fins are generally retained for trade. W ith increasing fin prices, the distinction between bycatch and directed catch in many fisheries is becoming less clear. There are some directed fisheries for sport angling and to provide m eat and fins for domestic m arkets and international trade.

The blue shark is a large, slender shark reaching c. 380 cm TL. It is one of the m ost wide-ranging of all sharks, being found throughout tropical and temperate seas from about 60°N to 50°S latitude. It is found from the surface to about 350 m depth and occasionally occurs close inshore where the continental shelf is narrow. This is a highly m igratory species, with complex movement patterns related to reproduction (there is segregation of the population by age and sex for much of the year) and the distribution of prey. Trans-Atlantic migrations have been dem onstrated from tagging studies, and m ore limited tagging in the Pacific has shown movements of up to 4,000 km annually.

A bout 50% of males in the A tlantic are sexually m ature by 218 cm (4-6 years), and females are fully m ature from 221 cm (5-7 years), although pregnant fish as small as 183 cm have been recorded from the Pacific. The species is viviparous, usually producing litters in spring or summer tha t average about 30 young (although a litter o f 135 has been recorded) after a gestation period of 9-12 months. The females can store sperm for a year after m ating before fertilisation. A t b irth the pups are 35-50 cm long. Pupping takes place in offshore nursery areas in the M editerranean and off the Iberian peninsula in the Atlantic, and in the sub-Arctic boundary of the Pacific where there is a large prey biomass for the juveniles. Juvenile blue sharks rem ain in the nursery areas and do no t take p art in the extensive adult m igrations until they reach a length of c. 130 cm.

The m ain th reat to blue sharks is from bycatch in high- seas fisheries (Bonfil 1994). Very few data on the scale of these catches are recorded, as there is virtually no observer coverage on the high seas. Some observer data have been

collected from fisheries operating in national fishing zones. Blue shark catch rates by longliners vary considerably, with some exceptionally high rates of 70-83 per 1,000 hooks obtained from longlining during research, to a minimum of 3.2 per 1,000 hooks. Logbook records, where available, are generally in single figures per 1,000 hooks, bu t these usually under-report catches. A conservative estimate of five blue sharks per 1,000 hooks would give a global bycatch from Japanese and K orean longliners of 2.8 million blue sharks. Bonfil (1994) estim ated total worldwide longline effort in 1989 as 750 million hooks taking a bycatch of 4 million blue sharks on the high seas. A n estim ated 2.2-2.5 million blue sharks were taken as bycatch by driftnet fisheries in the same year. D riftnet fishing effort is now much reduced, bu t the am ount of longlining has increased and Francis and Griggs (1997) report th a t the blue shark bycatch in the tuna longline fishery off the New Zealand coast considerably exceeds the catch of the target species.

Because of their high abundance, blue sharks are likely a keystone species in the oceanic ecosystem. N othing is known, however, o f their stock structure or population sizes and it is impossible to determine the effects of removing six million blue sharks annually on either blue shark populations or ocean ecology. A lthough blue sharks are among the m ost widespread, fecund, and fastest-growing elasmobranchs, their general life history characteristics still severely limit their ability to w ithstand such heavy fishing pressure.

The IU C N Red List assessment for this species is “Lower Risk, near threatened” globally.

[Summarised from Stevens in press c.]

4.3.3 Status of the white shark Carcharodon carcharias (Linnaeus, 1758)

The white shark Carcharodon carcharias is a member of the family Lamnidae and related to other mackerel sharks (makos and porbeagles). It is a marine m acro-predator reaching a maximum size of c. 700 cm TL. The white shark has a cosm opolitan distribution, occurring in coastal and pelagic waters, but has also been recorded in small numbers from mid-ocean fisheries. As an apex predator, it is generally rare, even in favoured locations where the species may reliably be found and studied. Despite this low population density, this shark is considered to be of significant ecological importance. A lthough the white shark has protected status in parts of its range (see Table 4, page 20), it is threatened by bycatch, sports angling, and some directed fisheries.

The white shark is a relatively fast-growing bu t late- m aturing K-selected species, reproducing by aplacental viviparity (the embryos are nourished in the uterus by unfertilised eggs). Litter size is 2-10 and length at birth ranges from 120 to 150 cm TL. M aturity is reached at the

15

very large size of 450-500 cm TL (probably 12-15 years of age) for m ost females and 350-380 cm TL (8-9 years) for males. There is, therefore, a high probability of immature white sharks being fished before they can breed. M ature females are particu larly scarce. F requency o f litter production is unknown, but if gestation exceeds one year (as is the case for some related sharks), females may only produce young every 2-3 years.

Because this is a rare species, the main targeted fishery is by recreational anglers, with the jaws and teeth being highly valued as trophies. Some other directed fisheries also supply the international curio trade. A large set of jaws may be w orth US$10,000 to a collector and there is reportedly also a m arket for neonates. This fish tends to actively investigate hum an activity, making it a relatively easy target. The main source of mortality, however, is th ro u g h bycatch in com m ercial fisheries, including accidental take in areas where it is protected. H abitat degradation as a result of pollution and overfishing ( particularly of prey species ) also threatens the white shark. These impacts may largely exclude the species from feeding or pupping areas where it was historically more abundant.

The IU C N Red List assessment for this species is “Vulnerable A lb ,c,d , A2c,d” .

[Summarised from Fergusson et al. in press.]

4.3.4 Status of the kitefin shark Dalatias licha (Bonnaterre, 1788)

The kitefin shark Dalatias licha is a relatively common, deeper-water dogfish unevenly distributed on continental and insular shelves and continental slopes from warm tem perate to tropical areas. It represents one of the very large num ber of poorly known, deepwater elasmobranchs that have been subject only to relatively small-scale directed fisheries until very recently, but are now likely to come under increased fishing pressure as more fisheries move into deeper water.

The kitefin shark is primarily a solitary, bottom-dwelling species, which can range well off the seabed. It feeds on a broad range of bony fishes, other elasmobranchs, and invertebrates. Its maximum size is at least 120 cm TL for males and 160 cm for females. As for m ost deepwater species of elasmobranchs, there is no inform ation available on growth rates, age at m aturity, and life span, but because of the low productivity of very stable deepwater habitats, they are assumed to be particularly slow to grow and reproduce. The kitefin shark is known to be ovovivipare us, giving birth to litters o f 10-16 pups c. 30 cm long.

The kitefin shark has been the subject of directed, deepwater line fisheries, but these appear to be of limited potential, with rapid degradation of stocks reported when large catches are taken in a fishing season. It is feared that deepwater sharks are even less able to sustain fisheries than

species from more productive shallow-water environments. The increasing need for commercial fisheries to move off the continental shelves to sustain catch levels and recent trends in the development of deepwater trawling gear, however, indicate that this and other poorly known deep- sea elasmobranchs will undoubtedly come under increased pressure in the future.

The IU C N Red List assessment for this species is “Lower Risk, near threatened” . This takes into account the difficulties of projecting the effects of future deep-sea fishing pressure on populations of such a vulnerable, but poorly-known species.

[Summarised from Com pagno and C ook 1996 and in press c.]

4.3.5 Status of the largetooth sawfish Pristis perotteti (Müller and Henle, 1841)

The sawfishes are a very unusual group of highly modified large rays that probably evolved from ancient sharks. There are three to eight species of sawfishes in the Family Pristidae (the taxonom y requires revision). All possess a long, blade-like snout studded with lateral teeth. All live in shallow coastal, estuarine and/or freshwater habitats in warm-temperate to tropical regions.

The restricted habitat range of sawfishes and their great vulnerability to fisheries have resulted in very serious population declines for most, if not all, known species over the past 50 years. The largetooth sawfish Pristis perotteti was once relatively common in warm, shallow, nearshore marine, estuarine and freshwater habitats in the Pacific and A tlan tic oceans, w here it had a wide b u t disjunct distribution. It is now only rarely recorded.

Adult largeto oth sawfish reach a size of up to 600 cm TL with a possible maximum age of c. 30 years. M aturity probably occurs at about ten years and a length of 240- 300 cm. All sawfish species are ovo viviparous; the largetooth sawfish gives birth after a five-month gestation to between one and 11 fully developed young of c. 76 cm TL.

Intensive fishing pressure at m ost locations within the species’ range has resulted in a dram atic decline in local stocks of this and other sawfishes. U nfortunately, even a very serious reduction in stocks does not cause a cessation in fishing effort: because of the long tooth-studded saw, all sawfish species are extremely vulnerable from birth to incidental capture in net gear set for other species. Sawfishes also yield valuable fisheries products, so are landed when caught rather than released.

The fins of all sawfish species are very highly priced in the shark fin trade ( some also have valuable flesh). The saw is used in traditional Chinese medicine and appears in trade as a curio. In addition, aquaria collect sawfishes from the wild for display (there is no known record of successful captive breeding) and there is also limited sports fishing

16

(for trophies). Since sawfishes occur in areas where hum an activities are particularly intensive, hab ita t loss and degradation are also significant threats to the species’ survival.

The IU C N Red List assessment for this species is “Critically Endangered (A la,b,c, A2c,d)”.

[Summarised from Compagno and Cook 1995 and Cook et al. in press a.]

4.3.6 Status of the Brazilian guitarfish Rhinobatos horkelii Müller & Henle, 1841

The Brazilian guitarfish Rhinobatos horkelii is a viviparous ray with a maxium recorded to tal length of 142 cm, distributed along the coast of southern Brazil. U ntil 1985, the species was highly abundan t and constituted an im portant resource for the artesanal beach seine fishery in summer, when gravid (pregnant) females form ed dense concentrations in shallow coastal waters. This case study illustrates the extent to which a fishery can rapidly deplete a species which has a restricted geographic range and is caught at all stages of the lifecycle, bo th as a target species and at the same time as part of a multi-species fishery.

Fem ales reach m a tu rity a t 7 -9 years o ld and c. l lO c m T L ; males at 5-6 years of age. The species segregates by age and sex and carries out marked seasonal migrations during its annual reproductive cycle. Pregnant females are found in shallow coastal waters for the five summer m onths before birth of their litters of four to 12 pups ( dependent on size of m other ) and subsequent mating. A dult males come inshore only briefly during the pupping and mating season. All adults then disperse into deep water over the continental shelf, but the newborns and juveniles remain in the inshore pupping grounds year round.

From about 1960, this species was caught by otter and pair trawlers in depths of 10-100 m, and by beach seine net in depths of up to 10 m in summer, with the latter taking 98% pregnant females. A nnual landings increased from 100 t in 1960 to 2,029 t in 1984 and 1,927 t in 1989, then decreased continually (with falling catch per unit effort) to 254 t in 1992 and 178 t in 1995. As trawl catches decreased, bottom gili nets became the main fishing method. Guitarfish abundance fell by 96% between 1984 and 1994, but landings continued because of increased gillnet fishing effort.

This species is extremely vulnerable to over-exploitation because the inshore areas where pregnant females and adult males congregate and juveniles remain year-round are so heavily fished. Juveniles are first taken by the fishery at the age of four, two to three years before they reach m aturity. Because the fishery targets several species and is no t dependent on R. horkelii, the extirpation of this species will not cause the fishery to close.

The IU C N Red List assessment for this species is “Critically Endangered (A lb,d; A2b,d)”.

[Summarised from Lessa and Vooren (in press).]

4.3.7 Status of the common or gray skate Raja batis (Linnaeus, 1758)

The com m on or gray skate is one of more than 160 skates in the family Rajidae and is the largest European skate species, attaining a length of 285 cm (fem ales) and 205 cm (males). A bottom-dwelling species, it is found primarily on the outer shelf, at depths of 200 m or greater, although historically it was com m on in coastal waters in the N o rth ­east A tlantic and adjoining seas. Males m ature a t an age of c. 11 years and length of 125 cm, and females presumably at a ra ther larger size. M aximum age is c. 50 years. Fecundity is estimated at 40 large eggs per year, with young hatching at a size of up to 21-22 cm.

Rajids are an im portant com ponent of the demersal fisheries of north-west Europe, and the com m on skate has traditionally been landed because of its large size and high-quality meat. A t the end of the last century it was considered one of the more com m on elasm obranchs in Scottish waters, comprising nearly 40% of landings. In the 1930s, it comprised nearly 40% of the tonnage of skates landed by D utch fishermen from near the Dogger Bank in the N orth Sea, although only juveniles of 20-60 cm were landed. This figure had dropped to 10% in 1970, the last year in which this species was recorded separately. It appears to have been absent from the southern and central N orth Sea since then. Catches elsewhere in the region have declined. The disappearance of the Irish Sea population ( Brander 1981 ) is notable as the first reported case of a fish being brought to the brink of extinction by commercial fishing (albeit only on a regional basis).

The life history of this species, particularly its age and very large size at m aturity, makes the com m on skate especially vulnerable to over-exploitation when com pared to other rajids. M ost size classes are taken in fishing nets, and m ortality of the large juveniles is high. Fishing pressure on skates from target and multi-species fisheries in the N orth-east A tlantic is so intense tha t few of this species can survive to maturity. Fishing pressure in the N orth Sea, probably representative of other heavily fished areas, is calculated to result in a 34%—37% decrease in num bers of R batis annually. The species has been replaced in much of its form er range in the southern and central N orth Sea by smaller, faster-m aturing and m ore fecund Raja species.

The com m on skate is still taken by French, British, and Icelandic fisherm en, w ith landings appearing to be increasing in France, probably as a result o f expanding deepwater fisheries. Because m ost countries do no t record skate and ray landings to species, analysis of trends and stock status is difficult.

The IU C N R ed L ist assessm ent fo r the w orld popu la tion of this species is “Endangered (A lb ,c,d ; A 2b,c,d)”. Inshore European populations are “Critically Endangered” under the same criteria.

[Summarised from Ellis and W alker (in press).]

17

Chapter 5

Management of Chondrichthyan Fishes

5.1 Fisheries managementAs the previous discussion of chondrichthyan biology suggests, the life history strategy of these fishes requires conservative, risk-averse m anagem ent if their populations and fisheries are to rem ain viable. Regardless, on a global basis, m ost shark fisheries are completely unm onitored, unregulated and unm anaged.

Historically, chondrichthyan fishes have generally been of low economic value. They make only a small c o n tr ib u tio n to the overall w orld fisheries catch . Consequently, they are a low priority for research and m anagem ent funds com pared with m ore valuable teleost and invertebrate resources. This has been com pounded by the traditionally negative image of sharks as malevolent c rea tu res re sponsib le fo r a tta ck s on hum ans and damage to fish catch. In addition, incidental capture, particularly of batoids in bottom trawl fisheries and pelagic sharks in tuna and billfish fisheries, has led to large and poorly docum ented m ortality. M ore recently, certain chondrich thyan p roducts, especially shark fins and cartilage, have escalated in price - dram atically increasing the value of the catch and the incentive to retain them. The result is a very poorly docum ented global catch th a t is estim ated to be twice tha t reported (Bonfil 1994).

In addition to increasing value and catches, a further compelling reason for the im plem entation of m anagem ent plans for chondrichthyans stems from their specialised life-history strategy and role in the ecosystem. M ost chondrichthyans are predators at or near the top of marine (and some estuarine and freshwater) food chains and, as such, tend to be naturally low in abundance ( H off and M usick 1990). They typically grow slowly, m ature late in life, have low fecundity and are long-lived. Unlike m ost bony fishes in which the survival of millions of eggs and larvae are often largely dependent on environm ental v a riab les, ch o n d rich th y an s ex h ib it a m uch closer relationship between the num ber of young produced and the num ber of breeding adults. This ‘K-selected’ life history strategy makes them particularly vulnerable to fishing pressure and, once depleted, stocks can take m any years to recover (Hoenig and G ruber 1990). M aintenance of biodiversity and ecosystem structure is another reason for controlling the indiscrim inate destruction and fishing of chondrichthyans. The com plex interactions between species in m arine ecosystems are poorly understood and removal of top predators may well trigger undesirable consequences for o ther fishery resources, as well as ecosystem function.

Historically, m ost targeted chondrichthyan fisheries have been u n reg u la ted an d have rap id ly becom e unsustainable (Anderson 1990b). In 1994, about 105 countries reported chondrichthyan landings to FAO. Twenty-six nations are considered to be m ajor shark- fishing nations, each landing m ore than 10,000 metric tons of chondrichthyans a year. Only four o f these - Australia, New Zealand, the United States, and C anada - have established integrated research and m anagem ent plans for some of their shark fisheries. One is also in development in South Africa. A pparently only about 11 countries in the w orld have any federal m anagem ent a t all for their elasm obranch fisheries. Table 3 presents a sum m ary of the m anagem ent measures implemented for shark fisheries around the world. U nfortunately, fishery regulations can only be effective with adequate enforcement. In many areas where fishery regulations have been implemented, there has been little o r no enfo rcem ent to ensure compliance. A few additional countries protect one or m ore chondrichthyan species (Table 4, page 20), bu t do no t actually manage any fisheries.

E ffo rts to enhance m anagem ent fo r sharks are complicated by m any factors. M ost fundam ental is the lack of basic needs such as adequate identification guides for the num erous batoid species or for elasm obranch species by region, and baseline data on species-specific abundances, life history characteristics, fishing effort, catches, and discards at sea. Some highly m igratory shark species cross ju risd ictional boundaries, which complicates m anagem ent action and makes aggregation of relevant data difficult. An exceptional lack of data, fleet structure and control makes m anagem ent of artisanal fisheries even more challenging than th a t for commercial fishing operations. In addition, the long life span and slow m aturation of m any sharks often means the effects of fishing and m anagem ent will no t be apparent until 15 to 20 years after initiation. In mixed-species fisheries, which are com m on for sharks, less abundant and incidentally caught species can become depleted long before there are signs of trouble in the catches of the dom inant species. Improved data on the trade in elasm obranchs and their p roducts would significantly increase our understanding of levels and trends in the exploitation of these fishes.

In those very few cases where shark fisheries are m anaged, regimes have sometimes failed to prevent overfishing or to prom ote population recovery. This has been the result, inter alia, of contro ls having been implemented too late, or not being sufficiently restrictive.

18

Table 3. Management tools currently implemented for domestic shark fisheries by shark fishing nations.Country Management Quotas

planLicences/limitedentry

Habitat/area closures: adult/

nursery1

Closed Minimum seasons sizes

Gearrestrictions1

Prohibition on finning

Recreational bag limits

Bycatchmonitoring(species-specific)

Australia - Southern Shark Fishery (of V ictoria, Tasmania, South Australia)

1988 X X X X Finning in EEZ by domestic vessels discouraged, but

not prohibited

X Limited

South Western Shark Fishery (of Western Australia)

1988,1998

X X Finning within EEZ discouraged but not prohibited

X X

Northern Australia ? Fishery (of Queensland, Northern Territory, and N. o f W. Australia)

X X X(area within 15 miles of

coast closed)

X Finning discouraged but not prohibited

within EEZ

Minimal

Brazil Proposed for drift nets

Proposed

Canada 1995 X X X X

European Union X 2

Ireland Recreational only (self-regulated)

Limited

Maldives X X

Mexico In development X X3 X

New Zealand X4 ITQs Recreational X Limited

Norway Only for spiny dogfish Squalus acanthias

Oman Prohibited

Portugal (Azores) Net length for kitefin shark

Dalatias licha

South Africa In development5 X 6 Pelagic & demersal longline permits

in Cape Province. Gillnet licences

Xcommercial

only

X X Minimal

United Kingdom For rays, some Sea Fisheries Districts

United States - Atlantic and Gulf coasts, S ta te7 & Federal waters

1993 On large coastals (22 spp)

small coastals (7 spp) & pelagios

(10 spp)8

Proposed X Proposed X X Limited

Pacific Coast (California, Oregon, and Washington)

X 9 Alopiasvulpinus

only

Alopiasvulpinus

only

Triakis semifasciata in California

only

Californiaonly

For seven shark species in California

(1992)

Limited

Mediterranean Sea X10

1 Area c losures and gear restric tions spec ific to shark fisheries only.2 Q uotas o f 400 m etric tonnes (t) liver w e igh t fo r basking shark C etorh inus m axim us and 200 t porbeagle Lam na nasus by Norwegian vessels in EU

w aters. 125 t porbeagle quota fo r Faeroese vessels. North Sea quota fo r all skates (Raja spp.) is based on previous ca tches, not s to ck assessm ents.3 Nursery areas protected fo r bull shark Carcharinus leucus, b lack ii p shark C. lim batus, bon net head shark Sphyrna tiburo , lem on shark Negaprion

brevirostris, and others in Cam peche and Q uintana Roo.4 Quota m anagem ent system (est. 1986) sets quotas fo r som e species, includ ing to p e Galeorhinus galeus, rig M uste lus lenticu la tus, elephant fish

C allorh inchus m ilii, sp iny dogfish Squalus acanthias, and Raja spp.5 Research and m anagem ent plan w ill focus on to p e G. galeus, sm ooth ho und M uste lus m uste lus, and S t Joseph C allorh inchus capensis.6 S potted gully shark Triakis m ega lopterus, sand tig e r shark Carcharias taurus, Pyjama shark Poroderm a a fricanum , and leopard ca ts hark

P. pantheriunum to be decom m ercia l i sed-restric ted to sport fisheries.7 For deta ils o f A tlan tic and Gulf S tate shark fishery regulations see Camhi 1998.8 Excludes m anagem ent quotas fo r sp iny dogfish Squalus acanthias desp ite large increase in landings fo r expo rt m arkets.9 No federal m anagem ent, but T ri-S ta te M onito ring Plan in California, Oregon, and W ashington fo r th resher shark Alopias vulpinus.10 Mediterranean popu lations o f s ho rtf in m ako Isurus oxyrinchus, porbeagle Lamna nasus, blue shark P rionace g lauca, w h ite ska te Raja alba and

angelshark Squatina squatina are lis ted on A nnex III o f a p rotocol to the Barcelona C onvention and (with devil ray M obula m obular) on A ppend ix III o f the Bern C onvention on Conservation o f European W ild life and Natural H abita ts. O nce ratified, these lis tings w ill require the explo ita tion o f these species to be regulated.

19

Table 4. Legally protected elasmobranch species.

Protected species Country or region Legislation Date Other information

W hite shark Carcharodon carcharias

Australian EEZAll Australian range statesUSA A tlantic & Gulf CoastsSouth AfricaNamibiaCaliforniaMaldivesMediterranean Sea

Federal Endangered SpeciesS tate legislationFishery Management Plan

Calif, legislature (SB 144)

Barcelona Conv. Annex II

19971984-1997

19931997

1995

Extends th roughout 200 m ile EEZ98

Recreational catch-&-release perm itted

AB 522 gave tem p, protection in 1993

Protocol signed, but not ratified

Whale shark Rhincodon typus Western AustraliaUSA A tlantic & Gulf CoastsMaldivesPhilippines

S tate Fisheries Legislation Fishery Management Plan Fisheries regulation Fishery Adm in. Order 193

1997 19951998

Grey nurse/sand tiger shark Carcharias taurus

AustraliaNSW AustraliaUSA A tlantic & Gulf Coasts

Federal Endangered SpeciesS tate legislationFishery Management Plan

199719841997

Bigeye sandtiger Carcharias norohai

USA Atlantic & Gulf Coasts Fishery Management Plan 1997

S ho rtf in mako Isurus oxyrinchus Canada Fishery Management Plan 1995 Target fisheries prohibited, landing o f by catch perm itted

Basking shark Cetorhinus m axim us

USA A tlantic & Gulf Coasts Florida S tate waters Great Britain Guernsey, UK Isle o f Man, UK Mediterranean Sea

New Zealand 1

Fishery Management Plan Florida Adm inistrative Code W ildlife & Countryside Act Fisheries legislation W ildlife Act, Schedule 5 Barcelona Conv. Annex II Bern Conv. A ppend ix II Fishery legislation

1997

1998 1997 1990 1995 1997

Extends to the 12 m ile territorial lim it

Protected species Protocol signed, but not ratified Reservation lodged by EU Target fisheries prohibited, landing o f by catch perm itted

SawsharksOrder Pristiophoriform es

USA A tlantic & Gulf Coasts Florida S tate waters

Fishery Management Plan Florida Adm inistrative Code

1997

Sawfishes Pristis sp p. IndonesiaUSA A tlantic & Gulf Coasts Florida S tate waters

Protected species legislation Fishery Management Plan Florida Adm inistrative Code

1997Species found in Lake Sentan i, Irian Jaya

Spotted eagle ray Aetobatis narinari

USA Atlantic & Gulf Coasts Florida S tate waters

Fishery Management Plan Florida Adm inistrative Code

1997

Giant devil ray M obula m obu la r Mediterranean Sea Barcelona Conv. Annex II 1995 Protocol signed, but not ratified

Manta ray Manta birostris Philippines Fishery Adm in. Order 193 1998

All chondrichthyans Israel

1 Many e lasm obranchs are proh ib ited ta rge t species in New Zealand, but bycatch can be qu ite high, so e ffective pro tection may be m inim al.

F or m anagem ent to be effective, it m ust be based on the biological constraints of the species rather than the short­term economics of the fishery. Past shark m anagem ent has been particularly ineffective because managers relied on techniques developed for much m ore productive and resilient teleost fishes (M usick 1995). U ntil recently, few shark fisheries models have been used as the basis for management.

For example, in the United States, large coastal sharks in the north-w estern A tlantic and G ulf o f Mexico had already been overfished by the time a US Federal Fishery M anagem ent P lan (FM P) was implemented in 1993. M anagem ent actions have apparently stemmed the rapid decline in catch per unit effort experienced during the 1980s. Some populations, however, are still reduced to

only 10°/%50% of their 1970s abundances (M usick et a l 1993). A 1996 biological assessm ent concluded th a t fishing m ortality would have to be cut by 50% or m ore for there to be a “strong probability of stock rebuilding” (NOAA 1996). The subsequent assessment in 1998 has suggested tha t even further restrictions on catch are needed for recovery to take place (N O A A 1998a). The fact tha t virtually no commercial shark fishery in the United States has been m anaged sustainably, despite considerable investments in shark fishery research and management, emphasises the extreme vulnerability of shark populations to overfishing.

M anagem ent is even more difficult for the m any species tha t exhibit wide-ranging movements and have a complex population structure. These resources are often shared

20

betw een states or na tions, and require cooperative management at an intergovernm ental level ( FAO Fisheries D epartm ent 1994). Oceanic shark resources extend into international waters, yet there are few regulatory bodies collecting shark data, m uch less im plem enting shark m anagem ent measures. International efforts to establish such data collection and conservation program m es have just recently begun. For example, in September 1998, the Northwest Atlantic Fisheries O rganization(NAFO) agreed to improve the reporting of elasm obranch catch statistics and carry out analyses of the distribution and abundance o f e lasm obranchs in the N A F O R eg u la to ry A rea (international waters in FA O Statistical Area 21 ). A Plan of Action for Sharks, including guidelines for improved m onitoring, recording and m anagem ent activities, is being discussed at the inter-governm ental FA O Committee on Fisheries meeting in O ctober 1998.

The U N A greem ent on S trad d lin g and H ighly M igratory Fish Stocks could be used as a fram ework for prom oting the conservation of oceanic sharks by expanding the role of intergovernm ental bodies, such as the Inter A m erican Tropical Tuna Com m ission (IA TTC), the International Commission for the Conservation of Atlantic Tunas (ICCAT), the South Pacific Commission (SPC) and the F o ru m F ish e rie s A gency (F F A ), o r the establishm ent of new regional m anagem ent regimes for sharks where none currently exist. Yet, this agreement currently remains 12 signatories short of coming into force. As a m atter of priority, countries should accede to and ratify this Agreement and become active members of treaty organisations relevant to chondrichthyans.

5.2 Species protectionIn recent years, a num ber of countries have begun to enact protective legislation or regulation for a few species of sharks as concern over the threats to these species has increased. W hite sharks Carcharodon carcharias, for example, have been afforded varying levels of protection in Australia, Israel, Nam ibia, South Africa and the United States. Basking sharks Cetorhinus maximus and whale sharks Rhincodon typus are now also protected to varying degrees in a few countries (see Table 4). It is unfortunately only the largest and m ost ‘charism atic’ sharks that are receiving the benefits of such protection. M any other species, including some skates and rays, are in as great, if not greater, need of conservation action and legal protection.

Unfortunately, a declaration of protected status without im p lem en ta tion o f enforceable regu la tions - while reassuring to governments and international bodies - will result in little effective protection. For example, several M editerranean populations of sharks and rays listed as protected on the Barcelona and Bern Conventions receive no real protection because these agreements are not ratified or enforced. The protection of the basking shark in U K coastal waters may not have any effect in stemming the apparent decline in numbers there if target fisheries and bycatch continue to rem ove significant num bers of individuals from the same population elsewhere in its range.

Finally, the loss or deterioration of critical habitats, which may be a strong contributory factor to a population decline, is not halted by species protection legislation alone.

21

Chapter 6

Conclusions

6.1 SummaryThe life histories of chondrichthyan fishes make them highly vulnerable to over-exploitation and therefore inappropriate targets for large-scale commercial fisheries in the absence of effective management. Shark fisheries and landings, however, continue to grow in directed fisheries seeking fins, cartilage and meat, and in ‘take-all’ fisheries. In m ost places, exploitation occurs in the absence of even the m ost basic m onitoring and management.

Effective conservation and management of sharks must address the array of factors affecting their populations, including directed fisheries, bycatch and discard mortality, loss of habitat, and changes in marine trophic structure, among others. In the context of fisheries, there is an urgent need to develop and implement management regimes that take into account the biological constraints and life histories of sharks. For example, fishing mortality cannot continually exceed the ability of the population to replace itself through reproduction if the fishery is to persist long-term.

To develop effective fisheries management regimes for sharks and address their broader conservation needs, greater attention is needed to improve the quality of ecological and fisheries data and to develop and apply management mechanisms and tools, including to control and m onitor trade. Specific data and other requirements are set out below. Addressing these needs will require increased investment of hum an and financial resources in research and management, in developing the necessary policy, legal and institutional frameworks, and in training and other capacity-building to implement management measures.

Given the biological vulnerability of sharks and their relatives, these species clearly demand a precautionary approach to their management. The United Nations Food and Agriculture Organization has made a strong case for such an approach in capture fisheries, noting the need to take management action even where there are uncertainties and gaps in knowledge (FAO 1995 ), as is the case for most shark fisheries today. A truly precautionary approach to shark fishery development would dictate that fisheries only be conducted where stock assessments are available and stringent monitoring and management regimes are in place. However, few biological and long-term fisheries data are available, even for species that are abundant in fisheries and/or of considerable value in trade. While management is hampered by the lack of data on most species’ population status and productivity, shark biology and fisheries dynamics are now sufficiently well understood to enable precautionary management to be introduced wherever such fisheries occur.

6.2 Ecological data needsIf shark fishing is to be sustainable, m anagem ent m ust be driven by the biological capacity of the sharks themselves. This will require better knowledge of the biology, ecology and life history of the populations being exploited, and of rarer species that may be taken as bycatch.1. Basic taxonomic knowledge is lacking for some groups of

chondrichthyans, particularly the batoids and chimaeras, many of which are very im portant in fisheries. Greater taxonomic research effort is needed, including species description and genetic research into stock structure.

2. Models used to assess elasmobranch fisheries should be appropriate for long-lived animals with low productivity and a close relationship between stock and recruitment. Optimal models require species-specific data on:• reproductive characteristics ( age at maturity, gestation

period and average annual pups per female);• critical habitats a t different life stages, including

mating, pupping and nursery grounds;• growth rates and age structure;• m ortality ( natural and in fisheries ) for all age classes;• stock and relative species abundance; and• stock structure and m igration patterns.

3. Assessment of the global and regional status of all species.

6.3 Fisheries data needsBecause much of the assessment and m onitoring of shark populations relies on fisheries data, there is a need to develop and implement mechanisms to collect and enhance the reliability of these data, at national and sub-national, as well as regional and international, level, through fisheries m anagement and other bodies. Particularly im portant are:1. D ata on shark fishing m ortality by species, gear type

and region, including current and historical records of:• commercial, artisanal and recreational catches;• size and age structure and sex composition of catch;• landings (including num ber and weight of fishes);• bycatch, discards and discard mortality; and• catch per unit effort (CPUE).

2. Socio-economic data on shark fisheries - commercial, recreational and artisanal - including fleet and vessel size, gears used, areas fished, numbers of fishers, markets and values for different products, and the structure of trade.

3. Fishery-independent data.4. Standardised data collection and reporting methods, for

comparison of trends between regions and over time.

22

6.4 Management measuresW ith the exception of a few countries tha t have instituted national measures for their shark fisheries or protection for individual species, there are virtually no controls on shark fisheries around the world. There is an urgent need for management and monitoring to be instituted at the national, regional and international levels to prevent fisheries collapse and the extirpation of species and populations. Each shark fishery is unique, but FA O ’s Precautionary A pproach (1995) provides guidance on the minimal management actions needed for b o th new and existing fisheries. Cooperation is necessary among all parties interested in the long-term productivity of shark populations.

T he b io lo g y o f sh a rk s req u ires a p a r tic u la r ly conservative approach to fisheries management. Ideally, shark fisheries should not be established or proceed in the absence of a management plan, which should inter alia:1. Focus on individual populations (stocks) if possible, or

onspeciesor groups with similar life-history characteristics.2. Provide a precautionary buffer by maintaining biomass

above levels associated with maximum sustainable yields.3. Address the need to avoid recruitment overfishing by

ensuring that adequate numbers of fish survive to maturity.4. W here adequate data exist, use assessment models

relevant to sharks ( i.e. stage- or age-based demographic matrixmodels ) rather than traditional models for teleosts (surplus production or biomass dynamic models).

5. Encourage commercial fishing practices that reduce chondrichthyan bycatch and/or facilitate live release and discourage wasteful practices such as finning.

6. Take into account the vulnerability of less common chondrichthyans taken asa bycatch tha t may be rapidly driven to stock collapse or extirpation while more common species support fisheries.

7. Encourage live release of recreational catches and participation in tagging programmes.

8. Include international bi- or multi-lateral agreements, based on the precautionary approach and other elements of sound fisheries management.

Effective management measures include the following:1. Limited entry (instituted as early as possible in the

development of the fishery).2. Commercial, recreational and artisanal catch quotas or

bag limits (incorporating bycatch).3. Size limits (so tha t enough fish m ature and reproduce).4. Closed seasons (to reduce overall fishing m ortality or

protect vulnerable aggregations on mating, nursery or pupping grounds).

5. Closed areas (e.g. fishery reserves or sanctuaries, to serve as refugia for fisheries productivity, or to protect critical habitats or threatened species or populations).

6. G ear restrictions (to protect certain species or age classes and reduce bycatch).

7. Selective take of males only.8. Protection of threatened species.9. Prohibition of finning and requirement to land whole

carcasses ( which will also improve recording of accurate fisheries statistics and enforcement of regulations).

The recent growth in shark fisheries has been driven, in part, by the expansion of international trade in shark fins and other products. Better understanding of the quantities, sources and utilisation of shark fishery products is necessary to inform management of shark fisheries. M anagement will benefit from:1. Improved docum entation on international shark trade,

including:• m onitoring of species, products, and volumes in

trade, and their value; and• details of importing/exporting countries and

oceans/areas of origin.2. C ontrols on trade in rare chondrich thyan fishes

threatened by over-exploitation for trade (e.g. for the fin, curio or aquarium markets).

3. Evaluation of elasm obranch species for possible listing on th e C o n v en tio n on In te rn a tio n a l T rad e in Endangered Species (CITES) Appendices (to help provide needed trade data).

In addition to the controls to reduce the risk of overfishing, investment in a num ber of management tools is needed to address the data collection and m onitoring needs outlined above, including:1. Preparation of regional and global identification guides

for species and products.2. Preparation of a procedures m anual to help standardise

data collection, which will facilitate in ternational m anagem ent measures.

3. Training programmes within fisheries agencies to apply management measures and standardised data collection techniques.

4. Mechanisms for involving commercial, recreational and artisanal fishers in m onitoring and management decision-making.

5. Increased enforcement capability.

Finally, despite frequent reference to the limitations of available data, enough is known about shark biology and the dynamics of shark fisheries to begin implementing basic management measures wherever these fisheries exist. T hat is, lack of data m ust not be used to justify lack of m anagement. Increasing hum an-induced pressures are rapidly intensifying the risk of shark population collapse, species endangerm ent and even extinction. Increased co m m itm en t to sh ark research , m an ag em en t and conservation at the national, regional and international levels is crucial to the future viability of these exceptionally vulnerable animals.

23

Annex 1. Life-history traits of some chondrichthyan species.1Scientific and common names

Age to maturity (years)

Size (cm TL) (at birth, maturity,

and maximum)

Life span (years)

Littersize

Annual rate of population

increase

Reproductiveperiodicity

(years)

Gestationtim e

(months)

N o to r y n c h u s c e p e d ia n u s Broadnose sevengill shark

M: 4-5 M :11-21 F: 16-20

Birth: 40-45 Mat: M: 150 F: 220

Max: 290-300

M :23-32 F: 35-49

32

20,82-95(max)

2.6% 2 10-12

R h in c o d o n ty p u s Whale shark

? Birth: 60 Mat: F: >560 Max: -1370

? 300 ? ? ?

G in g ly m o s to m a c irra tu m Nurse shark

? Birth: 27-30 Mat: 150 Max: 425

? 20-30 ? ? ?

C a rc h a r ia s ta u r u s Sand tiger, spotted raggedtooth, or gray nurse shark

6-128

Birth: 95-105 Mat: 220 Max: 318

32(NE Pacific)

1-2 4.6% 2 12

C a r c h a r o d o n c a rc h a r ia s White shark

M :9-10 F: 12-14

Birth: 120-150 Mat: M: 350-410 Mat: F: 400-430

Max 594

36 2-10 4.1 % 2? >12?

I s u ru s o x y r in c h u s Shortfin mako

M: 3 F: 7-8 av. 5

Birth: 60-70 Mat: M: 195 Mat: F: 280 Max: 394

28 4-16 5.2% 2 -3 12-18

L a m n a n a s u s Porbeagle shark

4 -8 F: 7.5

Birth: 60-75 Mat: M: 165 F: 152-225

Max: 300-365

30 1-5 ? 1-3? 9-18?

C e to r h in u s m a x im u s Basking shark

M : 12-16 F: 20

Birth: 150-170 M: 500-700 F: 810-980

Max: 1000-1300

50 5-6 ? 2? >12?

A lo p ia s v u lp in u s Thresher shark

7 Birth: 114-150 Mat: M: 319 F: 376

Max: 491

? 2 -6 7.2% ? 9

M u s te lu s a n ta r c t ic u s Gummy shark

4 -5 Birth: M: 30-40 Mat: F: 85 M: 80

Max: 175

16 10-38(mean=14)

12% annually in W. Australia

2 year in Bass Strait

11-12

M u s te lu s h e n le i Brown sm oothhound

2 -3 Birth: 19-21 Mat: M: 51-63 F: 52-66

Max: 95

15 3-5 13.6% 1 10-11

G a le o rh in u s g a le u s Tope, school, or soupfin shark

F: 10-15 M: 8-10

Birth: 30-40 Mat: F: 134-140 Mat: M: 125-135

Max: 155-200

40-60 8-50 (mean =28)

3.3% 1-3 12

C a rc h a r h in u s fa lc ifo rm is Silky shark

M: 10 F: >12

Birth: 76-87 Mat: M: 187-225 Mat: F: 213-245

Max: 330

M: >20 F: >22

2-15 ? 1-2 12

C a rc h a r h in u s le u c a s Bull shark

6 -8 or 15

Birth: 56-81 Mat: 200

Max: 300-320

M: 16 F: 12-27

1-13 2.7% ? 10-11

C a rc h a r h in u s l im b a tu s Blacktip shark

M: 4-5 F: 6 -8

Birth: 53-65 Mat: M: 130 F: >155 Max: M: 175 F: 193

10-18 2 -44 -7

2 .2% -13.6%5.6%

2 11-12

1 M ost o f the data presented here are from C om pagno (1984) and Sm ith et al. In press, w ith updates for a small num ber o f species.

24

Distributioncosmopolitan, pelagic,

wide-ranging, regional, demersal country endemic,

localised, restricted

Habitat informationinsular, oceanic, pupping/nursery bathyal (>200m), grounds

coastal (shore-200m), (estuarine, reef, mangrove, estuarine near-/offshore)

Fisheries pressureDirected Incidental

(high, some, (high, some, low, none) low, none)

References

w ide -rang ing , te m pe ra te w a te rs

dem ersa l coasta l estuarine -nearshore

high high C om pagno in p ress a, Ebert 1990, Ebert 1989, Van Dykhuizen & M o lle t 1992

cosm op o lita n , w arm tem pera te

and trop ica l

pe lag ic coas ta l-o ce a n ic ? low low Joung e t al. 1996, N orm an in p ress

reg iona l (A tlantic and E. Pacific)

dem ersa l coasta l nearshore low low C astro 1997, C arrie r 1991, C lark & von S ch m id t 1965

w ide -rang ing , te m pe ra te to su b -tro p ica l

dem ersa l coasta l nearshore-estuarine

low high B rans te tte r& M usick 1994, G ilmore 1993, G ilm ore e f al. 1983, G oldm an 1998, Po lla rd e t al. 1996, Po lla rd & S m ith in press, S m inkey 1996

w ide -rang ing , te m pera te to boreal w a te rs

pe lag ic coas ta l-o ce a n ic p robab lycoasta l

low (high in som e tro p h y

fisheries)

low (high in beach ne tting areas)

C a illie t e f al. 1985, Fergusson 1996, Fergusson e t al. in press, Francis 1996, U ch ida e f al. 1996

cosm op o lita n , trop ica l, s u b ­trop ica l and tem pe ra te

pe lag ic oceanic ,som etim es

coasta l

p rob a b lycoasta l

high [in som e

recreational fisheries]

high Caillie t & M o lle t 1997,C a illie t e f al. 1983, C liff e f al. 1990, M o lle t e f al. 1997, P ra tt &Casey 1983, S tevens in p ress b

w ide -rang ingdem ersa l

pe lag ic and oceanic

coasta l and oceanic

o ffshore high high Aasen 1963, Ellis & S hack ley 1995, Gauld 1989, S tevens in p ress a

w ide -rang ing , te m pe ra te to boreal w a ters

pe lag ic coasta l o ffshore? som e som e Fow ler in press b, Kunzlik 1988, Pauly 1978, Parker & S to tt 1965, Sund 1943

cosm op o lita n , warm w aters

pe lag ic coas ta l-o ce a n ic inshore high? som e? G oldm an in p ress

endem ic(tem perateAustra lia)

dem ersa l coasta l ? high high? Lenanton e t al. 1990, M ou lton e t al. 1992, W a lke r 1996, 1983, 1994a, b, & in press

loca lised dem ersa l coasta l ? som e som e Y ud in & C a illie t 1990

w ide -rang ingsom etim es

pe lag ic

dem ersa l, (but dow n to 800 m)

coasta land

estuarine

nearshore high som e Capape & M ellinger 1988,G rant e f al. 1979, O lsen 1954,Peres & V o o re n 1991, R ipley 1946, S tevens in p ress d, W a lke r e f al. 1995

w ide -rang ing in te m pe ra te and tro p ica l w a ters

pe lag ic co a s ta l- oceanic

o ffshore high high Bontii 1990 & in press,Bontii e t al. 1993, B rans te tte r 1987b

wide-ranging in subtropical to tropica l waters

pelagic coastal into estuaries and

freshwater

estuarine high high Burgess e f al. in press, Branstetter & Stiles 1987

cosm opolitan in warm-temperate to tropica l waters

pelagic coastal estuarine high low Branstetter 1987c, Burgess & Branstetter in press, Castro 1996, Dudley & C liff 1993, Killam & Parsons 1989, W intner & C liff 1996

25

Annex 1.... continuedScientific and common names

Age to maturity (years)

Size (cm TL) (at birth, maturity,

and maximum)

Life span (years)

Littersize

Annual rate of population

increase

Reproductiveperiodicity

(years)

Gestationtim e

(months)

C a rc h a r h in u s lo n g im a n u s Oceanic w hite tip shark

4 -5 Birth: 60-65 Mat: F: 180-200 M: 175-195

Max: 310

22 1-14 6.9% ? 12

C a rc h a r h in u s m e la n o p te r u s Blacktip reef shark (Eastern hemisphere)

? Birth: 30-35 Mat: 95-110

Max: 140-180

? 2 -4 ? 1 or 2 8 -9 or 10-11

or ? 16

C a rc h a r h in u s o b s c u r u s Dusky shark

M: 19 F: 21

Birth: 80-100 Mat: F: 280

Max: 365

40-50 3-14 (mean 607)

2.8%2%

2 or 3 12 or 22-24

C a rc h a r h in u s p lu m b e u s Sandbar shark

13-16 [29 in

another study]

Birth: 60-65 Mat: M: 170 F: >180 Max: >239 (in USA)

25-35 8-13 2.2 % -1 1.9% 3.4% , or 5.2% if mat =29 years

2 9-12

G a le o c e r d o c u v ie r Tiger shark

8-10 Birth: 59-90 Mat: M: 226-290 F: 250-350

Max: 450-600

50 10-80av. 35

4.3% probably 2 yrs 12-16

G ly p h is sp.Borneo river shark

? ? ? ? ? ? ?

N e g a p r io n b r e v ir o s tr is Lemon shark

11-13 Birth: 60 M: 224 (mat) Mat: M: 224 F: 239

Max: M: >279 F: >285

27 4-17 1.2% ? ?

P r io n a c e g la u c a Blue shark

F: 5-7 M: 4 -6

Birth: 35-50 Mat: M: 180-218 Mat: F: 180-220

Max: 383

20 40 av. (4-135)

6.25% females? males annually?

9-12

R h iz o p r io n o d o n te r r a e n o v a e Atlantic sharpnose shark

3 -4 Birth: 30-35 Mat: M: 80-85 F: 85-90

Max: 110

10 4-61-7

4.5%8.8%

annual 10-12

T r ia e n o d o n o b e s u s W hitetip reef shark

5 or 8 -9

Birth: 52-60 Mat: 105 Max: 170

16-25 1-52 -3

4.9% ? >5?

S p h y r n a le w in i Scalloped hammerhead

M :4-10 F: 4-15

Birth: 31-55 Mat: M: 140-280 Mat: F: 150-300 Max: 329-420

35 15-4012-38

2.8% ? 9-12

S p h y r n a tib u ro Bonnethead shark

F: 2 -3 M: 3

Birth: 35-40 Mat: M: 68-85 F: 80-85

Max: M: 124 F: 150

12 4-16 0.01-0.27 annual? ?

D a la tia s lich a Kitefin shark

? Birth: 30 Mat: M: 100 F: 120 Max: M: 120 F: 160

? 10-16 ? ? ?

S q u a lu s a c a n th ia s Spiny or piked dogfish or spurdog NW A tlantic population (NW Pacific population)

M :6-14 F: 10-12

(F: 12-23)

Birth: 20-30 Mat: M: 60 F: 70

Max: 100-125

M: 35 F: 40-50

(70)

2 -15 av. 4 -9

2 .3% -3 .5%

(1.7%)

2 (but no resting stage)

18-24

S q u a tin a c a lifo rn ica Pacific angelshark

8-13 Birth: 21-26 Mat: M: 75-80 Mat: F: 86-108

Max: M: 114 F: 152

35 1-11 mean 6

3 .9% -6% 1 10-12

P r is tis m ic r o d o n Greattooth or freshwater sawfish

? 700 (max) ? ? ? ? ?

26

Distributioncosmopolitan,

w ide-ranging, regional, country endemic,

localised, restricted

pelagic,demersal

Habitat informationinsular, oceanic, pupping/nursery bathyal (>200m), grounds

coastal (shore-200m), (estuarine, reef, mangrove, estuarine near-/offshore)

Fisheries pressureDirected Incidental

(high, some, (high, some, low, none) low, none)

References

cosmopolitan pelagic oceanic;insular

oceanic high high Backus e ta /. 1956, Seki e t a l . undated, Smale in press a

widespread demersal insular (reefs) insular high high Heupel in press, Last & Stevens 1994, Stevens 1984

wide-ranging in sub-trop ica l and

tem perate oceans

coastal-pelagic

coastal offshore in Australia

inshore USA

high (in USA & Australia)

high Branstetter & Burgess 1996,Camhi e t a l . in press, Cortés in press a, Goldman 1998, Natanson e t al. 1995

wide-ranging tropica l and

tem perate oceans

pelagic coastal,oceanic

nearshore high some,moderate

Casey & Natanson 1992, Casey e t al. 1985, Sminkey & Musick 1995, 1996, M usick in press

cosm opolitan in tropica l and

subtropical waters

coastal-pelagic

coastal wide-ranging, may enter

estuarine areas

locallyhigh

low Branstetter e t al. 1987, Clark & von Schm idt 1965, De C ro s ta e f al. 1984, Randall 1992, S im pfendorfer in press b, Sm inkey 1996, Tester 1969

restricted to rivers in Borneo?

localised demersal freshwater-estuarine

low low-m oderate(bycatch)

regional demersal coastal, insular and reefs

nearshore high high Brown & Gruber 1988, Sundstroem & Gruber in press

cosmopolitan pelagic oceanic,sometimes

coastal

offshore low high Amorim 1992, Cailliet e t a l . 1983, Castro & Mejuto 1995, Hazin 1993, Nakano 1994, Pratt 1979, Stevens 1976 & in press c, Tanakae?al. 1990

w ide-ranging in warm temperate

to tropica l Atlantic

demersal coastal estuarine high high Branstetter 1987a,Cortés 1995, in press a, b, Parsons 1983, 1985

wide-ranging (in Indo-Pacific)

demersal coastal nearshore some high Anderson & Ahmed 1993, Fourmanoir 1961, Last & Stevens 1994, Smale in press b

w ide-ranging in warm temperate

pelagic coastal-oceanic nearshore high high Branstetter 1987b, Kotas in press, Stevens & Lyle 1989

to tropica l waters

regional demersal coastal and reefs

? some high Carlson & Parsons 1997, C ortés in press c, Cortés & Parsons 1996, Parsons 1993a, 1993b

wide-ranging, warm temperate

to tropical waters

demersal bathyal bathyal high in some

locations

high in some

locations

Compagno & Cook in press c

cosmopolitan, tem perate to

subarctic waters

demersal coastal offshore high high Fordham in press, Gauld 1979, Jensen 1965, Jones & Geen 1977, Ketchen 1975, N am m ackefa/. 1985, NOAA 1998b, Saunders & McFarlane 1993

localised, cold to warm

demersal coastal coastal high high Cailliet in press b, Cailliet e f a/.1992, Natanson & Cailliet 1986,1990

temperate waters

localised in trop ics

demersal freshwater ? high high Compagno & Cook in press b, Last & Stevens 1994

27

Annex 1.... continuedScientific and common names

Age to maturity (years)

Size (cm TL) (at birth, maturity,

and maximum)

Life span (years)

Littersize

Annual rate of population

increase

Reproductiveperiodicity

(years)

Gestationtim e

(months)

P r is tis p e c t in a ta Sm alltooth or w ide sawfish

? 760 (max) ? 15-20 ? ? ?

R h y n c h o b a tu s d j id d e n s is Giant guitarfish

? M: 110 (mat) >300 (max)

? ? ? ? ?

R h in o b a to s h o rke lii Brazilian guitarfish

F: 7 -9 M: 5 -6

Mat: 90 -120 ? 4-12 ? 1 11-12

B a th y ra ja a b y s s ic o la Deepsea skate

? M: 110 (mat) ? ?

(eggs)

? ? n/a

R a ja b a t is Common skate

11 Birth: 21-22 Mat: M: 125

Max: 254

50 40 eggs ? annual? n/a

R a ja (D ip tu ru s) b in o c u la ta Big skate

M :8-11 F: 12

Mat: M: 100-110 F: 130 Max: 168-240

? 1-7 embryos per egg case

? ? n/a

R a ja (Raja) c la v a ta Thornback skate or ray

9-12 M: 69 (mat) F: 72 (mat)

M :36-43 F: 39-46

52 eggs/ year

0 or less in North Sea

annual n/a

R a ja (D ip tu ru s) rh ina Longnose skate

M: 7-8 F: 8-10

Mat: M: 60 F: >70 Max: 137

? ? ? ? n/a

M y lio b a t is c a li fo r n ic a Bat ray

M: 4, F: 5 Birth 20 (DW)Mat: M: 60 F: 88 (DW)

M ax 180 (DW -disk width)

M: 10 F: 25 2 -5 ? 1 -12

H im a n tu ra c h a o p h r a y a Giant freshwater stingray or whipray

? Mat: 100 (disk width) Max: 200 (disk width)

? ? ? ? ?

28

Distributioncosmopolitan,

w ide-ranging, regional, country endemic,

localised, restricted

pelagic,demersal

Habitat informationinsular, oceanic, pupping/nursery bathyal (>200m), grounds

coastal (shore-200m), (estuarine, reef, mangrove, estuarine near-/offshore)

Fisheries pressureDirected Incidental

(high, some, (high, some, low, none) low, none)

References

wide-ranging(disjunct)

demersal coastal and freshwater

? high high Adam s in press, Bigelow & Schroeder 1953

wide-ranging in tropica l waters

demersal coastal ? high high Sim pfendorfer in press c, Last & Stevens 1994

regional demersal coastal nearshore high high Lessa 1982, Lessa e f a/. 1986, Lessa & Vooren in press

regional demersal bathyal ? none (too rare)

some Cook e t a l. in press b, Zorzi & Anderson 1988

regional, boreal to cool temperate

(NE Atlantic)

demersal coastal ? high high Ellis & W alker in press, Du Buit 1972 & 1976, B rander 1981, Fahy 1991

regional (NE Pacific)

demersal coastal nearshore and offshore

high high Ellis & Dulvy in press, M artin & Zorzi 1993, Zeiner & W olf 1993, DeLacy & Chapman 1935, Hitz 1964

wide-ranging in tem perate water

demersal coastal estuarine-nearshore

high high Brander & Palmer 1985, Capape 1977, Ellis &S hackley 1995, Ellis in press, Holden 1975, Holden & V ince 1973, Nottage & Perkins 1983, Ryland & Ajayi 1984

regional (NE Pacific)

demersal coastal nearshore and offshore

high high Zeiner & W olf 1993

w est coast USA

demersal coastal estuaries some some Caillie t in press a,M artin & C aillie t 1988 a & b

localised demersal freshwater-estuarine

freshwater some some Compagno & Cook in press a, Last & Stevens 1994

29

Annex 2. Summary of the 1994 IUCN Red List Categories and Criteria.This tab le shou ld be used in con ju n c tion w ith Tab le 2, to help exp la in th e basis o f th e Red L ist assessm ents app lied to va rious ch ondrich thyan fishes by the IU C N /SS C S hark S pec ia lis t G roup.

Use any o f the A -E crite ria C ritically Endangered VulnerableEndangered

A. Declining Populationpopula tion decline rate at least: 80% in 10 years 50% in 10 years 20% in 10 yearsusing e ither o r 3 generations o r 3 generations or 3 genera tions1. popu la tion reductions observed, estim ated,

inferred, o r suspected in the past or2. popu la tion decline p ro jec ted o r suspected in the

fu ture based on:a) d irec t observationb) an index o f abundance approp ria te fo r the taxonc) a decline in area o f occupancy, ex tent o f

occu rrence a n d /o r qua lity o f hab ita td) actual o r po tentia l levels o f exp lo ita tione) the e ffec ts o f in troduced taxa, hybrid isa tion,

pathogens, po llu tants, com pe tito rs , o r parasites

B. Sm all D istribution and Decline o r FluctuationEither ex tent o f occurrence: < 100 km 2 < 5,000 km 2 < 2 0 ,0 0 0 km 2or area o f occupancy: < 10 km 2 < 500 km 2 < 2,000 km 2and 2 o f the fo llow ing 3:1. e ither severe ly fragm ented (isolated

subpopu la tions w ith a reduced p robab ility o freco lon ization, if one extinct) o r know n to existat a lim ited num ber o f locations: + 1 < 5 < 10

2. con tinu ing decline in any o f the fo llow ing : any rate any rate any ratea) ex tent o f occurrenceb) area o f occupancyc) area, extent a n d /o r qua lity o f hab ita td) num ber o f loca tions o r subpopu la tionse) num ber o f m ature ind iv idua ls

3. flu c tua tions in any o f the fo llow ing : > 1 o rder/m ag. < 1 order/m ag. < 1 order/m ag.a) ex tent o f occurrenceb) area o f occupancyc) num ber o f loca tions o r subpopu la tionsd) num ber o f m ature ind iv idua ls

C. Sm all Population S ize and D eclineN um ber o f m ature ind ividuals: < 2 5 0 < 2,500 < 10,000and 1 o f the fo llow ing 2:1. rap id decline rate 25% in 3 years 20% in 5 years 10% in 10 years

o r 1 generation o r 2 generations or 3 genera tions2. con tinu ing decline any rate any rate any rate

and e ither a) fragm ented all su b -p o p s < 50 all su b -p o p s < 250 all su b -p o p s < 1,000or b) all ind iv idua ls in a s ing le subpopu la tion

D. Very Sm all or R estric ted PopulationEither:1. num ber o f m ature ind ividuals: < 5 0 < 2 5 0 < 1 ,0 0 02. popu la tion is susceptib le : (not app licable) (not app licable) area o f occupancy

< 100 km 2 orno. o f loca tions < 5

E. Q uantitative AnalysisInd icating the p robab ility o f extinc tion 50% in 10 years o r 20% in 20 years o r 10% in 100 yearsin the w ild to be at least: 3 generations 5 generations

30

References

Aasen, O. 1963. Length and growth of the porbeagle (Lamna nasus B onnaterrei in the northw est Atlantic. Fiskeridir. Skr. 13(6): 20.

Adams, W .F. In press. Sm alltooth or wide sawfish Pristis pectinata. In: Fowler et al. in press b.

Alverson, D .L., M .H. Freem an, S.A. M urawski and J.G . Pope. 1994. A global assessment o f fisheries bycatch and discards. FAO Fisheries Technical Paperno. 339. Rome: F ood and Agriculture O rganization of the United N ations. 233 pp.

Amorim, A .F 1992. Estudo da biología, pesca e reproducao do cacao azul, Prionace glauca L. 1758, capturado no sudeste e sul do Brasil. D octoral Thesis, Universidade E stadual Paulista , R io C laro, Sao Paulo, Brazil. 176 pp.

Anderson, E.D. 1990a. Estimates of large shark catches in the western A tlantic and G ulf of Mexico, 1960-1986. In: Pratt, H.L. Jr., S.H. G ruber and T. Taniuchi (eds.) Elasmobranchs as living resources: advances in the biology, ecology, systematics, and the status o f fisheries. Pp. 443-454. US D epartm ent of Commerce, N O A A Technical R eport N M FS 90.

A nderson, E .D . 1990b. F ishery m odels as applied to e lasm obranch fisheries. In: P ra tt, H .L . Jr., S.H. G ruber and T. Taniuchi (eds.) Elasmobranchs as living resources: advances in the biology, ecology, system atics, and the status o f fisheries. Pp. 473-484. US D epartm en t o f Com m erce, N O A A Technical R ep o rt N M F S 90.

Anderson, R .C. and H. Ahmed. 1993. The Shark Fisheries o f the Maldives. M inistry of Fisheries and Agriculture, Republic of M aldives and Food and A gricultural O rganization of the United N ations. 76 pp.

A nonym ous. 1995. R ep o rt o f the Study G roup on Elasm obranchFishes.ICESCM 1995/G:3. International Council for the Exploration of the Sea. Copenhagen, Denm ark.

Anonym ous. 1997. Biological and trade status of sharks. R eport o f the CITES Animals Committee ( Pursuant to R esolution Conference 9.17).

A rocha, F. 1997. The reproductive dynamics of swordfish Xiphias gladius L. and m anagem ent implications in the northw estern A tlantic. D issertation. U niversity of F lorida, Coral Gables, FL.

Auster, P.J. and R.W . Langton. 1998. The effects of fishing. MS prepared under contract to the American Fisheries Society. Bethesda, M aryland, 57pp.

Backus, R .H ., S. Springer and E.L. Arnold. 1956. A contribution to the natural history of the white-tip shark, Pterolam iops longimanus (Poey) D eep-Sea Research 3: 178-188.

Beamish, R .J. and G.A. M cFarlane. 1987. Current trends in age determ ination m ethodology. In: Summerfelt, R.C. and G.E. Haii (eds.) The Age and Growth o f Fish. Pp. 15^t2. Iowa State Univ. Press, Ames, USA.

Berrow, S.D., and C. H eardm an. 1994. The basking shark Cetorhinus maximus ( Gunnerus ) in Irish waters -pa tterns of distribution and abundance. Proc. Roy. Irish Acad. 94B, 2: 101-107.

Best, P.B. 1993. Increase rates in severely depleted stocks of baleen whales. IC E S J. mar. Sei. 50: 169-186.

Beverton, R .J.H . 1990. Small marine pelagic fish and the th reat of fishing: are they endangered? J. ofFish Biology 37(Suppl. A): 15-16.

Bigelow, H.B. and W .C. Schroeder. 1953. Sawfishes, guitarfishes, skates, rays, and chimaeroids. In: Tee Van, J., C .M . Breder, A .E. P arr, W .C. Schroeder and L.P.Schultz (eds.) Fishes o f the western North Atlantic. 1(2): 1-514. Sears Foundation for M arine Research, Yale University. New Haven, CT (USA).

Bonfil, R. 1990. C ontribution to the fisheries biology of the silky shark Carcharhinus falciformis ( Bibron 1839) from Y ucatan, Mexico. MSc Thesis, University of Wales, Bangor. 77 pp.

Bonfil, R . 1994. Overview o f world elasmobranch fisheries. FAO Fisheries Technical Paper no. 341. Rome: FAO. 119pp.

Bonfil, R . In press. Silky shark Carcharhinus falciformis. In: Fowler et al. in press b.

Bonfil, R., R . M ena and D. de Anda. 1993. Biological param eters of commercially exploited silky sharks, Carcharhinus falciformis, from the Campeche Bank, Mexico. In: S. Branstetter (ed.) Conservation Biologv o f Elasmobranchs. N O A A Technical Report N M FS 115. US D epartm ent of Commerce.

Brander, K. 1981. D isappearance of com m on skate Raja batis from Irish Sea. Nature, 290: 48^49.

Brander, K. and D. Palmer. 1985. G row th rate of Raja clavata in the N ortheast Irish Sea. J. Cons. int. Explor. M er, 42: 124-128.

Branstetter, S. 1987a. Age and grow th of newborn sharks held in laboratory aquaria, with comments on the life history of the A tlantic sharpnose shark, Rhizoprionodon terraenovae. Copeia 1987(2): 291-300.

Branstetter, S. 1987b. Age growth and reproductive biology of the silky shark, Carcharhinus falciform is, and the scalloped ham m erhead, Sphyrna lewini, from the no rth ­western G ulf of Mexico. Env. Biol. Fishes 19: 161-173.

Branstetter, S. 1987c. Age and growth estimates for blacktip, Carcharhinus limbatus, and spinner, C. brevipinna, sharks from the northw estern G ulf ofM exico. Copeia 1987(4): 964-974.

31

B ranstetter, S. 1990. Early life-history im plications of selected carcharh ino id and lam noid sharks of the northw est A tlantic . In: P ra tt, H .L . Jr., S.H. G ruber and T. T an iu ch i (eds.) E lasm obranchs as living reso u rces: a d va n ces in the b io lo g y , eco lo g y , system atics, and the status o f fisheries. Pp. 17-28. US D epartm en t of Com m erce, N O A A Technical R eport N M F S 90.

Branstetter, S. 1997. Burning the candle a t both ends. Shark News (Newsletter o f the IU C N Shark Specialist Group), 9: 4.

B ranstetter, S. and G .H . Burgess. 1996. C om m ercial Shark F ishery O bserver Program . C haracteriza tion and com parisons of the directed com m ercial shark fishery in the eastern G u lf o f M exico and off N o rth Carolina th rough an observer program . F inal R eport, M A R F IN A w ard N A 47FF0008, 33pp. + 11 tables + 20 figs.

Branstetter, S. and J.A. Musick. 1994. Age and growth estimates for the sand tiger shark in the N orthw estern A tlantic Ocean. Transactions o f the American Fisheries Society 123: 242-254.

Branstetter, S. and R. Stiles. 1987. Age and grow th estimates of the bull shark, Carcharhinus leucas, from the northern G ulf o f Mexico. Environ. Biol. Fishes. 20(3): 169-181.

Branstetter, S., J.A. M usick and J.A. Colvocoresses. 1987. A com parison of the age and grow th of the tiger shark, Galeocerdo cuvieri, from off Virginia and from the northw estern G ulf of Mexico. US National Marine Fisheries Service Fishery Bulletin 85: 269-79.

Brown, C.A. and S.H. Gruber. 1988. Age assessment of the lem on sh a rk , N egaprion brevirostris, using te tracy c lin e v a lid a te d v e rte b ra l c e n tra . Copeia 1988(3): 747-753.

Bryant, D., L. Burke, J. M cM anus and M. Spalding. 1998. Reefs at Risk. A M ap-based Indicator o f Threats to the W o rld ’s C oral Reefs. W orld R esources Institu te, In ternational Center for Living A quatic Resource M anagement, W orld Conservation M onitoring Centre, and United N ations Environm ent Program m e. 56pp.

Burgess, G .H . and S. Branstetter. In press. Blacktip shark Carcharhinus limbatus. In: Fowler et al. in press b.

Burgess, G .H ., C.A. Simpfendorfer and A. Amorim. In press. Bull shark Carcharhinus leucas. In: Fowler et al. in press b.

Cailliet, G .M . In press a. Bat ray M yliobatis californica. In: Fowler et al. in press b.

Cailliet, G .M . In press b. Pacific angel shark Squatina californica. In: Fowler et al. in press b.

C ailliet, G .F . and H .F . M ollet. 1997. P re lim inary demographic analysis of the shortfin m ako, Isurus oxyrinchus. Program and A bstracts o f 77th A nnual M eeting of A m erican Society of Ichthyology and Herpetology. 88pp.

Cailliet, G .M ., L.K. M artin, J.T. Harvey, D. Kusher and B.A. Welden. 1983. Preliminary studies on the age and growth of blue, Prionace glauca, com m on thresher, Alopias vulpinus, and shortfin mako, Isurus oxyrinchus, sharks from Califorrnian waters. In: Prince, E.D. and L.M. Pulos (eds. ) Proceedings ofthe international workshop on age determination o f oceanic pelagic fishes: Tunas, billfishes, and sharks. N O A A Technical Report, N M F S 8. Pp'. 179-188.

Cailliet, G .M ., L.J. N atanson, B.A. W eldon and D.A. Ebert. 1985. Preliminary studies on the age and growth of the white shark Carcharodon carcharias, using vertebral bands. South. Calif. Acad. Sei., Memoirs 9: 49-60.

Cailliet, G .M ., R.L. Radtke and B.A. Welden. 1986. Elasmo­branch age determination and verification: a review. In: Uyeno, T., R. Arai, T. Taniuchi and K. M atsuura (eds.) Indo-Pacific Fish Biology. Proceedings of the Second International Conference on Indo-Pacific Fishes. Pp. 345- 360. Tokyo: Ichthyological Society of Japan.

Cailliet, G .M ., H .F. Mollet, G .G . Pittenger, D. Bedford and L.J. N atanson. 1992. G row th and demography of the Pacific angel shark ( Squatina calif omica), based upon tag re tu rn s o ff C alifo rn ia . Australian J. M arine. Freshwater Res. 43: 1313-1330.

Camhi, M .D . 1993. The role of nest site selection in loggerhead ( Caretta caretta) sea turtle nest success and sex ratio control. Dissertation. Rutgers University, New Brunswick, N J. 251 pp.

Camhi, M. 1998. Sharks on the Fine: a State-by-State analysis o f sharks and their fisheries. N ational A udubon Society Living Oceans Program . USA.

Camhi, M., J. Musick and C. Simpfendorfer. In press. Dusky shark Carcharhinus obscurus. In: Fowler et al. in press b.

Capape, C. 1977. C ontribution a la biologie des Rajidae des cotes tunisiennes X. Raja clavata Linne, 1758: Etude complementaire de la fécondité. Bull. Off. natn. Peck Tunisie, 1(2): 169-172.

Capape, C. and J. Mellinger. 1988. Nouvelles données sur la biologie de la reproduction du milandre, Galeorhinus galeus (Linne, 1758), (Pisces, Triakidae) des cotes tunisiennes. Cali. Biol. Mar. 29: 135-146.

Carlson, J.K . and G .R. Parsons. 1997. Age and growth of the bonnethead shark, Sphyrna tiburo, from northwest Florida with comments on clinal variation. Em . Biol. Fish. 50: 331-341.

Carrier, J.C. 1991. G row th and aging: life history studies of the nurse shark. In: Gruber, S.H. (ed. ) Discovering Sharks. Pp. 68-69. Amer. L ittoral Soc. sp. publ. 14.

Casey, J. and R. Myers. 1998. N ear extinction of a large, widely distributed fish. Science 281: 690-692.

Casey, J.G . and L.J. N atanson. 1992. Revised estimates of age and growth of the sandbar shark (Carcharhinus plumbeus) from the western N orth Atlantic. Can. J. Fish. Aquat. Sei. 49: 1474-1477.

32

Casey, J.G ., H.L. P ratt Jr. andC .E . Stillwell. 1985. Age and growth of the sandbar shark (Carcharhinus plumbeus) from the western N orth Atlantic. Can. J. Fish. Aquat. Sei. 42: 963-975.

Castro, J.I. 1993. The shark nursery of Bulls Bay, South Carolina, with a review of the shark nurseries of the southeastern coast of the U nited States. Em . Biol. Fishes 38: 37—48.

Castro, J.I. 1996. Biology of the blacktip shark, Carcharhinus limbatus, off the southeastern United States. Bull. Mar. Sei. 59: 508-522.

Castro, J.I. 1997. Reproductive biology of the nurse shark, Ginglymostoma cirratum. Programme and Abstracts of the 77th A nnual M eeting of the American Society of Ichthyologists and Herpetologists.

Castro, J.A. and J. Mejuto. 1995. Reproductive parameters of blue shark, Prionace glauca, and other sharks in the G ulf of Guinea. Marine and Freshwater Research 46, 967-973.

Chang, W.-B., M.-Y. Leu and L.-S. Fang. 1997. Embryos of the whale shark Rhincodon typus: early growth and size distribution. Copeia 1997 (2): 444-446.

Chen, H .K . 1996. Shark fisheries and trade in sharks and shark products in Southeast Asia. T R A F F IC International, Cambridge, UK.

Chen, G.C.T., K .M . Liu, S.J. Joung and M .J. Phipps. 1996. Shark Fisheries and Trade in Taiwan. Unpublished T R A FFIC report. 48pp.

Clark, E. and K. von Schmidt. 1965. Sharks of the central G ulf coast of Florida. Bull. Mar. Sei. 15(1): 13-83.

Clemens, W .A. and G.V. Wilby. 1961. Fishes o f the Pacific Coast o f Canada. Fisheries Research Board of Canada. Bulletin N o. 68.

Cliff, G. and S.F.J. Dudley. 1992. Protection against shark attack in South Africa, 1952-1990. Aust. J. Mar. Freshw. Res. 43: 263-272.

Cliff, G., S.F.J. Dudley and B. Davis. 1990. Sharks caught in the protective gili nets o f N atal, South Africa. 3. The shorfin mako shark Isurus oxyrinchus (Rafinesque). South African Journal o f Marine Science, 9: 115-126.

Compagno, L.J.V. 1984. Sharks o f the world An annotated and illustrated catalogue o f shark species known to date. FAO Fish Synop. 125, part I: 1-249, part II: 251-655.

Compagno. L.J.V. In press a. Broadnose sevengill shark Notorynchus cepedianus. In: Fowler et al. in press b.

Compagno, L.J.V. In press b. W orld list of chondrichthyan fishes. In: Fowler et al. in press b.

Compagno, L.J.V. and S.F. Cook. 1995. The exploitation and conservation of freshwater elasmobranchs: status of taxa and prospects for the future. In: Oetinger, M .I., and G.D. Zorzi ( eds. ) The biology o f freshwater elasmobranchs. Journal o f Aquariculture and Aquatic Sciences, 7: 62-90.

Compagno, L.J.V. and S.F. Cook. 1996. Status of the kitefin shark Dalatias licha. Shark News (Newsletter of the IU C N Shark Specialist Group), 7: 4.

Com pagno, L.J.V. and S.F. Cook. In press a. G iant freshwater stingray Himantura chaophrya. In: Fowler et al. in press b.

Com pagno, L.J.V. and S.F. Cook. In press b. G reat-tooth or freshwater sawfish Pristis microdon. In: Fowler et al. in press b.

Com pagno, L.J.V. and S.F. Cook. In press c. Kitefin shark Dalatias licha. In: Fowler et al. in press b.

Compagno, L.J.V. and S.F. Cook. In press d. Pristiformes, sawfishes: Introduction. In: Fowler et al. in press b.

Cook, S., L. Com pagno and M. Oetinger. 1995. Status of the largetooth sawfish Pristis perotteti. Shark News (Newsletter of the IU C N Shark Specialist G roup), 4: 5

Cook, S.F., L.J.V. Com pagno and M .I. Oetinger. In press a. Largetooth sawfish Pristis perotteti. In: Fowler et al. in press b.

Cook, S.F., G. Zorzi and L.J.V. Com pagno. In press b. Deepsea skate Bathyraja abyssicola. In: Fowler et al. in press b.

Cortés, E. 1995. D em ographic analysis of the A tlantic sharpnose shark, Rhizoprionodon terraenovae, in the G ulf of Mexico. Fishery Bulletin 93( 1 ): 57-66.

Cortés, E. In press a. Dem ographic analysis as an aid in shark stock assessment and management. Fisheries Research.

C o rtés , E. In p ress b. A tla n tic sh a rk n o se sh a rk Rhizopriondon terraenovae. In: Fowler et al. in press b.

Cortés, E. In press c. Bonnethead shark Sphyrna tiburo. In: Fowler et al. in press b.

C ortés, E., and G .R P arsons. 1996. C om para tive dem ography of two populations of the bonnethead shark (Sphyrna tiburo). Can. J. Fish. Aquat. Sei. 53: 709-718.

Crouse, D .T., L.B. Crowder and H. Caswell. 1987. A stage-based population model for loggerhead sea turtles, and implications for conservation. Ecology’ 68: 1412— 1423.

Darling, J.D . and K .E. Keogh. 1994. Observations of basking sharks Cetorhinus maximus in C layoquot Sound, British Columbia. Canadian Field Naturalist 108: 199-210.

Dayton, P.K . 1998. Reversal of the burden of p roo f in fisheries management. Science 279: 821-822.

De Crosta, M .A., L.R. Taylor and J.D . Parrish. 1984. Age determ ination grow th and energetics of three species of carcharhinid sharks in Hawaii. In: Proceedings o f the Second Symposium on Resource Investigations in the Northwestern Hawaiian Islands. Vol. 2, pp 75-95. ( University of Hawaii Sea G ran t Miscellaneous R eport 84-01.)

DeLacy, A.C. and W .M . Chapm an. 1935. N otes on some elasm obranchs of Puget Sound, with descriptions of their egg cases. Copeia, 1935(2): 63-67.

Didier, D. In press. Chim aeroid fishes. In: Fowler et al. in press b.

33

D u Buit, M .H. 1972. Etude du stock de raies de la mer Celtique. Tray. Lab. BioJ. Halieutique, Université de Remies, 6: 13-31.

D u Buit, M.El. 1976. Age et croissance de Raja batis et de Raja naevus en M er Celtique. J. Cons. int. Explor. Mer, 37(3): 261-265.

Dudley, S.F.J. and G. Cliff. 1993. Sharks caught in the protective gili nets off N atal, South Africa. 7. The blacktip shark, C. limbatus (Valenciannes). S. Afr. J. Mar. Sei. 13: 237-254.

Dulvy, N .K . and J.D . Reynolds. In preparation. How many more skates face extinction?

Dulvy, N .K ., J.D . Reynolds, J.D . Metcalfe and J.Glanville. In preparation. Fisheries stability belies local extinctions and shifts in community structure in skates. Conservation Biology.

Ebert, D.A. 1989. Life history of the sevengill shark, N otorynchus cepedianus Peron , in tw o N o rth e rn California Bays. Calif. Fish Game 75(2): 102-112.

Ebert, D.A. 1990. The taxonom y, biogeography and biology of cow and frilled sharks (Chondrichthyes: Hexachiformes). PhD thesis, Rhodes University: vii + 308 pp + 44 pp of Appendices.

Ellis, J. In press. Thornback skate or ray Raja clavata. In: Fowler et al. in press b.

Ellis, J. and N. Dulvy. In press. Big skate Raja binoculata. In: Fowler et al. in press b.

Ellis, J.R . and S.E. Shackley. 1995. Observations on egg laying in the thornback ray. Journal o f Fish Biology 46: 903-904.

Ellis, J. and P. W alker. In press. Com m on skate Raja batis. In: Fowler et al. in press b.

Fahy, E. 1991. The southeastern ray Raja spp. fishery, with observations on the growth of rays in Irish waters and their commercial grading. Ir. Fish. Invest. Ser. B, 37:18pp.

FA O Fisheries Departm ent. 1994. World review o f highly migratory species and straddling stocks. FAO Fisheries Technical Paper, no. 337. Rome: FAO. 70pp.

FAO. 1995. Precautionary approach to fisheries. Part 1: Guidelines on the precautionary approach to capture fisheries and species introductions. FAO Fish, Tech, Paper 350/1. 52 pp.

FA O . 1998. In te rn a tio n a l P lan o f A ction fo r the conservation and management of sharks. Document FFCSS/98/3. FAO Fisheries D epartm ent Consultation on the management of fishing capacity, shark fisheries and incidental catch of seabirds in longline fisheries. Food and A griculture O rganization of the United N ations, Rome, October 1998.

Fergusson, I.K. 1996. R eport on the distribution and autecology of the white shark Carcharodon carcharias in the N orth-Eastern A tlantic and M editerranean Sea. In: Klimley, A.P. and D .G . Ainley (eds. ) Great white sharks: Ecology and Behaviour. C hap ter 30, pp 321-345. Academic Press, Orlando.

Fergusson, I.K., L.J.V. Compagno and M.A. M arks. In press. W hite shark Carcharodon carcharias. In: Fowler et al. in press b.

Fleming, E.H. and P.A. Papageorgiou. 1997. Shark Fisheries and Trade in Europe. 78pp. T R A FFIC .

Fordham , S.V. In press. Spiny dogfish Squalus acanthias. In: Fowler et al. in press b.

Forrester, C.R., K.S. Ketchen and C.C. W ong. 1972. M ercury content of spiny dogfish ( Squalus acanthias) in the strait of Georgia, British Columbia. Journal o f Research Board o f Canada 29, 1487-1490.

F ourm ano ir, P. 1961. R equins de la côte ouest de M adagascar. Mem, Inst. Sei. Madagascar (Ser. F). 4 :1 - 81.

Fowler, S.L. 1996a. Red list assessments for sharks and rays. Shark News (Newsletter of the IU C N Shark Specialist G roup), 8: 4-5.

Fowler, S.L. 1996b. Status of the basking shark, Cetorhinus maximus (Gunnerus). Shark News (Newsletter of the IU C N Shark Specialist Group), 6: 4.

Fowler, S.L. In press a. IU C N Red List Assessments. In: Fowler et al. in press b.

Fowler, S.L. Inpressb. Baskingshark, Cetorhinus maximus. In: Fowler et al. in press b.

Fowler, S.L., B.M. M anjaji, R .D . Cavanagh, L.J.V. Com pagno, S.G. M ycock and P.Last. In press a. E la sm o b ra n c h b io d iv e rs ity , c o n se rv a tio n and m anagem ent in Sabah. Proceedings of the 5th Indo- Pacific Fish Conference, Noum ea, New Caledonia, Novem ber 1997. Cybium,

Fowler, S.L., M. Camhi, G. Burgess, S. Fordham and J. Musick. In press b. Sharks, rays and chimaeras: the status o f the chondrichthyan fishes. IUCN/SSC Shark Specialist G roup. IU C N , G land, Switzerland, and Cambridge, UK.

Fowler, S.L., M. Camhi, G. Burgess, S. Fordham and J. Musick. In preparation. Sharks, rays and chimaeras: A Global Action Plan fo r the chondrichthyan fishes. IU CN / SSC Shark Specialist Group. IUCN, Gland, Switzerland, and Cambridge, UK.

Francis, M.P. 1996. Observations on a pregnant female white shark ( Carcharodon carcharias), with a review of reproduction in the species. In: Klimley, A.P. and D .G . Ainley (eds. ) Great white sharks: Ecology and Behaviour. Academic Press, Orlando.

Francis, M.P. and L.H. Griggs. 1997. Shark bycatch in New Zealand’s tuna longline fisheries (Abstract). 5th Indo-Pacific Fish Conference, Noumea, New Caledonia, 3-8 N ovem ber 1997, p. 31.

Frazer, N.B. and L.M . Ehrhart. 1985. Preliminary growth models for green (Chelonia mydas) and loggerhead (Caretta caretta) turtles in the wild. Copeia 1985:73-79.

G ales, R . 1993. C o-opera tive m echanism s fo r the c o n se rv a tio n o f a lb a tro s s . A u s tra l ia n N a tu re Conservation Agency. H obart, Tasm ania.

34

G auld, J. 1979. Reproduction and fecundity of the Scottish- Norwegian stocks of spurdogs Squalus acanthias, (L.) IC E SC .M . 1979/H:54. 16 pp.

G au ld , J.A . 1989. R eco rds o f p o rbeag les landed in Scotland, with observations on biology, distribution and exploitation of the species. Scottish Fisheries Research Report no. 45. D epartm ent of Agriculture and Fisheries for Scotland. Aberdeen.

G ilm ore, R .G . 1993. R eproductive biology of lam noid sharks. Environmental Biology o f Fishes 38: 95-114.

G ilm ore, R .G .D ., J.W . D odrill and P.A. Linley. 1983. R eproduction and embryonic development of the sand tiger shark, Odontaspis taurus (Rafinesque). Fisheries Bulletin 81(2): 201-225.

Goldman, K. 1998. Demographic analyses for sand tiger sharks and dusky sharks. Part 3. In: VIMS Shark Ecology Program, J.A. Musick, J. Gelsleichter, R.D. Grubbs, and K. Goldman. AppendixSB-IV-13. N O A A /N M FS Shark Evaluation Workshop, June 1998. Panama City, FL, 3 pp.

Goldm an, K. In press. Thresher shark Alopias vulpinus. In: Fowler et al. in press b.

G ra n t, C .J ., R .F . S an d lan d and A .M . O lsen. 1979. Estim ation of growth, mortality, and yield per recruit of th e A u s tra lia n schoo l sh a rk , G aleorhinus galeus (Macleay), from tag recoveries. Austr. J. Mar. Freshw. Res. 30: 625-637.

Hamlett,W .C. 1997. Reproductive modes of elasmobranchs. Shark News (Newsletter o f the IU C N Shark Specialist Group) 9: 1-3.

Hanfee, F. 1997. Trade in Sharks and Shark Products in India, A preliminary survey. 50pp. TR A FFIC .

Hazin, F.H.V. 1993. Fisheries-oceanographical study on tunas, billfishes and sharks in the southwestern equatorial A tlantic Ocean. D octoral thesis, G raduate School of Fisheries, Tokyo University of Fisheries, 286 pp.

H eupel, M. In press. B lacktip reef shark Carcharhinus melanopterus. In: Fowler et al. in press b.

Hillborn, R . and C.J. W alters. 1992. Quantitative Fisheries Stock Assessment. Chapm an and Haii, New York. 570 pp.

Hinman, K. and C. Safina. 1992. Summary and Recommend­ations. In: R .H . Stroud (ed. ) Stemming the tide o f coastal fish habitat loss. M arine Recreational Fisheries 14. Proceedings of a Symposium on conservation of coastal fish habitat, Baltimore, Maryland, M arch 1991. N ational Coalition for M arine Conservation, Georgia, USA.

Hitz, C.R. 1964. Observations on egg cases of the big skate (Raja binoculata G irard ) found in Oregon coastal waters. J. Fish, Res. Bd. Canada, 21: 851-854.

Hoenig, J.M ., and S.H. Gruber. 1990. Fife-history patterns in the e lasm obranchs: im p lica tio n s fo r fisheries management. In: Pratt, H .F. Jr., S.H. G ruber and T. Taniuchi (eds.) Elasmobranchs as living resources: advances in the biology, ecology, systematics, and the status o f fisheries. Pp. 1-16. US Departm ent of Commerce, N O A A Technical R eport N M FS 90.

Hoey, J.J., R .J. Conser and A.R. Bertolino. 1990. The western N orth Atlantic swordfish. In: Audubon Wildlife Report 1989/1990: 457^477.

Hoff, T.B. and J.A. Musick. 1990. W estern N orth Atlantic shark-fishery management problems and inform ational requirements. In: Pratt, H .F. Jr., S.H. G ruber and T. Taniuchi (eds.) Elasmobranchs as living resources: advances in the biology, ecology, systematics, and the status o f fisheries. Pp. 455^172. US D epartm ent of Commerce, N O A A Technical R eport N M FS 90.

Holden, M .J. 1974. Problems in the rational exploitation of elasm obranch populations and some suggested solutions. In: H arden Jones, F .R . (ed.) Sea Fisheries Research, Pp 117-137. New York: John Wiley and Sons.

Holden, M .J. 1975. The fecundity of Raja clavata in British waters. J. Cons. int. Explor. Mer, 36(2): 110-118.

Holden, M.J. and M .R. Vince. 1973. Age validation studies on the centra of Raja clavata using tetracycline. J. Cons, int. Explor. Mer, 35(1): 13-17.

H u n tsm an , G .R . In press. G ro u p ers (S erran id ae , Epinephelinae): Endangered apex predators of reef com m unities. In: M usick, J.A . (ed.) Ecology and Conservation o f long-lived animals. Proceedings of Symposium held during the American Fisheries Society 127th A nnual meeting, 25-28 August 1997, M onterey, California.

ICCAT. 1996. SCRS Executive Summary. Swordfish Detailed Report, Oct. 19 1996. M adrid, Spain.

IU CN . 1996.1996 IU C N R ed List o f Threatened Animals. IU CN , Gland, Switzerland.

Jensen, A.C. 1965. Fife history of the spiny dogfish. Fish, Bull. 65: 527-554.

Jones, B.C. and G .H . Geen. 1977. Age and growth of spiny dogfish ( Squalus acanthias F.) in the Strait of Georgia, British Columbia. Fish, Mar. Serv. Res. Dev. Tech, Rep. 669: 16 pp.

Joung, S.J., C.T. Chen, E. Clark, S. Uchida and W.Y.P. Huang. 1996. The whale shark, Rhincodon typus, is a livebearer: 300 embryos found in one ‘m egam am m a’ supreme. Environmental Biology o f Fishes, 46:219-223.

Ketchen, K.S. 1975. Age and growth of dogfish Squalus acanthias in British Columbia waters. Journal o f the Fisheries Research Board Canada 32: 43-59.

Killam, K.A. and G .R. Parsons. 1989. Age and growth of the blacktip shark, C. limbatus, near Tampa Bay, Florida. Fish. Bull. US 87(4): 845-858.

Klinowska, M. and J. Cooke. 1991. Dolphins, Porpoises and Whales o f the World. The IU C N R ed Data Book. IUCN, Gland, Switzerland and Cambridge, UK. 429 pp.

Kotas, J.E. In press. Scalloped hammerhead Sphyrna lewini. In: Fowler et al. in press b.

Krough, M. 1994. Spatial, seasonal and biological analysis o f sharks caught in the New South Wales Protective Beach meshing program. Aust. J. Mar. Freshw. Res. 45: 1089-1106.

35

Kunzlik, P.A. 1988. The basking shark. Scottish Fisheries Information Pamphlet No. 14. Departm ent of Agriculture and Fisheries for Scotland. Aberdeen.

Last, P.R. and J.D . Stevens. 1994. Sharks and rays o f Australia. CSIRO Division of Fisheries. 513 pp.

Laurie, A .H . 1937. The age of female blue whales and the effect of whaling on the stock. Discovery Rep. 15: 223- 284.

Laursen, L. and M. Bekoff. 1978. Loxodonta africana. Mammalian Species 92: 1-8.

Leet, W .S., C.M . Dewees and C.W . H augen. 1992. California’s Jiving marine resources and their utilization. California Sea G rant Extension Publication UCSGEP- 92-12: 257 pp.

Lenanton, R .C .J., D.I. Heald, M. Platell, M. Cliff and J. Shaw. 1990. Aspects of the reproductive biology of the gummy shark, Mustelus antarcticus G ünther, from w aters off the south coast o f W estern A ustralia. Australian Journal o f Marine and Freshwater Research 41: 807-822.

Lessa, R.P.T. 1982. Biologie et Dynamique des Populations de Rhinobatos horkelii du plateau Continental du Rio Grande do Sul. These de D octorat. Faculté des Sciences de Brest, Université de Bretagne Occidentale, 250 pp.

Lessa, R. and C.M . Vooren. In press. Brazilian guitarfish Rhinobatos horkelii. In: Fowler et al. in press b.

L essa , R ., C .M . V o o re n an d J. L ah ay e . 1986. Desenvolvimento e Ciclo Sexual das femeas, migraçôes e fecundidade da Viola, Rhinobatos horkelii (M uller & Henle, 1841) do Sul do Brasil. Atlantica, Rio G rande, 5-34p.

Lockyer, C. 1984. Review of baleen whale (Mysticeti) reproduction and implications for management. Rep. int. Whal. Commn (Special Issue 6): 27-50.

M cFarlane, G.A. and R.J. Beamish. 1987. Validation of the dorsal spine m ethod of age determ ination for spiny dogfish. In: Summerfelt, R .C. and G.E. Haii (eds.) The Age and Growth o f Fish. Pp. 287-300. Iowa State Univ. Press, Ames, USA.

McNally, K. 1976. The Sun-Fish Hunt. Blackstaff Press, Belfast.

M cPherson, G., N .A . Gribble and B. Lane. 1998. Shark control risk management in Queensland: a balance between acceptable levels o f bather safety, public responsibility and shark catch. In: G ribble, N .A ., G. M cPherson and B. Lane (eds.) Shark Management and Conservation. Proceedings from the Sharks and M an workshop of the Second W orld Fisheries Congress, Brisbane, Australia, August 1996.

M arshall, N .T. an d R . Barnett (eds.). 1997. Trade Review: The Trade in Sharks and Shark Products in the Western Indian and Southeast Atlantic Oceans. 132pp. TRA FFIC .

M artin, L.K. and G.M . Cailliet. 1988a. Age and growth of the bat ray, Myliobatis californica, off central California. Copeia 1988(3): 762-773.'

M artin , L .K . and G .M . Cailliet. 1988b. Aspects o f reproduction in the bat ray, M yliobatis californica, in central California. Copeia 1988(3): 754-761.

M artin, L. and Zorzi, G .D . 1993. Status and review of the California skate fishery. N O A A Tech. Rep. N M F S 115: 39-52.

M ollet, H .F ., G. Cliff, H .L. P ra tt and J.D . Stevens. 1997. Reproductive param eters of the shortfin m ako, Isurus oxyrinchus. Program and A bstracts of 77th A nnual M eeting ofA m erican Society of Ichthyology and Herpetology. Pp. 214.

Morrissey, J.F . and S.H. G ruber. 1993. Home range of juvenile lemon sharks, Negaprion brevirostris. Copeia 1993(2): 425^134.

M oulton, P.M ., T.I. W alker and S.R. Saddlier. 1992. Age and g ro w th stud ies o f gum m y shark , M uste lus antarcticus G ünther, and school shark, Galeorhinus galeus (Linnaeus), from southern-A ustralian waters. Australian Journal o f Marine and Freshwater Research 43, 1241-1267.

Musick, J. 1995. Critically endangered large coastal sharks, a case study: the sandbar shark, Carcharhinus plumbeus (N ardo, 1827). Shark News (Newsletter o f the IU C N Shark Specialist G roup), 5: 6-7.

Musick, J.A. 1997. Stocks at risk. Fisheries. 22(7): 31-32.Musick, J.A. 1998. Endangered m arine fishes: criteria and

identification of N orth American stocks at risk. Fisheries 23(2): 28-30.

Musick, J. In press. Sandbar shark Carcharhinus plumbeus. In: Fowler et al. in press b.

Musick, J.A. and J.A. Colvocoresses. 1988. Seasonal recru itm ent o f subtropical sharks in Chesapeake Bight, USA. In: Yanez, A., Y. Arancibia and D. Pauly (eds.) W orkshop on recruitm ent in tropical coastal dem ersal com m unities. Cam peche, M exico, 21-25 April 1986. FA O /U N ESCO , LO.C. W orkshop Rept. No. 44.

Musick, J.A ., S. B ranstetter and J.A. Colvocoresses. 1993. Trends in shark abundance from 1974 to 1991 for the Chesapeake Bight region of the U.S. M id-Atlantic coast. In: Branstetter, S. (ed.) Conservation Biologv o f Elasmobranchs. N O A A Technical Report N M FS 115,pp. 1-18.

N akano, H. 1994. Age, reproduction and m igration of blue shark in the N orth Pacific Ocean. Bulletin o f National Research Institute o f Far Seas Fisheries, 31: 141-256.

N am m ack, M .F., J.A. M usick and J.A. Colvocoresses. 1985. Life history of spiny dogfish off the N ortheastern U nited States. Transactions o f the American Fisheries Society 114: 367-376.

N atanson, L.J. and G .M . Cailliet. 1986. Reproduction and development of the Pacific angel shark, Squatina californica, off Santa Barbara, California. Copeia 1986 (4): 987-994.

36

N atanson, L.J. and G .M . Cailliet. 1990. Vertebral growth zone deposition in Pacific angel sharks. Copeia 1990(4): 1133-1145.

N atanson, L.J., J.G . Casey and N .E. Kohler. 1995. Age and growth estimates for the dusky shark, Carcharhinus obscurus, in the western N orth Atlantic Ocean. Fish, Bull. 93: 116-126.

N ational M arine Fisheries Service. 1995. Status of the Fishery Resources off the N ortheastern U nited States for 1994. NOAA /D ept. Of Commerce. W oods Flole, MA. 140 pp.

N O A A (N atio n a l O ceanographic and A tm ospheric A dm inistration). 1996. 1996 R eport o f the Shark E valuation W orkshop. N M F S , N O A A , D ept, of Commerce. June 1996. 80 pp.

N O A A (N atio n a l O ceanographic and A tm ospheric Adm inistration). 1998a. 1998 R eport of the Shark E valuation W orkshop. N M F S , N O A A , D ept, of Commerce. June 1998. 109 pp.

N O A A (N atio n a l O ceanographic and A tm ospheric Adm inistration). 1998b. Advisory R eport on Stock Status ( SAW-26 C orrigendum - spiny dogfish). NOAA, N M FS, N EFSC W oods Hole, Massachusetts.

N orm an, B. In press. W hale shark Rhincodon typus. In: Fowler et al. in press b.

N otarbarto lo di Sciara, G. In press. D ark clouds on M editerranean elasmobranchs: the case of the endemic skates. Shark News.

N ottage, A.S. and E.J. Perkins. 1983. G row th and m aturation of roker, Raja clavata L. in the Solway Firth. J. Fish Biol. 23: 43^48.

Nowell, K. and P. Jackson. 1996. Wild Cats: Status Survey and Conservation Action Plan. IUCN/SSC C at Specialist G roup. 406 pp.

Ohsumi, S. 1979. Interspecies relationships among some biological param eters in cetaceans and estimation of the natural mortality coefficient o f the Southern Hemisphere minke whale. Rep. int. Whal. Commn 29: 397-406.

Oliver, A. 1997. D raft discussion paper pursuant to CITES Resolution CONF. 9.17. An overview of the biological status of shark species. US N ational M arine Fisheries Service. R eport prepared for the CITES Animals C o m m ittee , S ilver S p rings, M ary lan d . 53pp + appendices.

Oliver, A. and T. W alker (eds. ). 1998a. D raft R eport of the N W A tlantic, G ulf of Mexico and C aribbean Sea Regional Strategy Developm ent W orkshop for the Conservation and M anagem ent of Sharks. Held 4-5 December 1997, M ote M arine Laboratory, Sarasota, Florida, USA.

Oliver, A. and T. W alker (eds. ). 1998b. D raft R eport o f the Indo-Pacific Regional Strategy Development W orkshop for the Conservation and M anagem ent o f Sharks. Held 9-10 N ovem ber 1997, South Pacific Commission, Noum ea, New Caledonia.

Oliver, A. and T. W alker (eds.). 1998c. D raft R ep o rt o f the E astern Pacific R egional S trategy D evelopm ent W orkshop for the C onservation and M anagem ent of Sharks. H eld 7-8 D ecem ber 1997, M onterey Bay A quarium , M onterey, C alifornia, USA.

Olsen, A .M . 1954. The biology, m igration , and grow th ra te o f the school sh a rk , G aleorhinus australis (M a c le a y ) (C a rc h a rh in id a e ) in s o u th -e a s te rn A ustra lian w aters. Austr. J. M ar. Freshw. Res. 5: 353-410.

P arker, H .W . and F .C . S to tt. 1965. Age, size and vertebral calcification in the basking shark Cetorhinus m axim us (G unnerus). Zoologische M ededelingen, 40(34): 305-319.

Parsons, G .R . 1983. E xam ination of vertebral rings of th e A tla n tic sh a rp n o se sh a rk , R hizoprionodon terraenovae. N ortheast G ulf Sei. 6 (1 ): 63-66.

Parsons, G .R . 1985. G row th and age estim ation of th e A tla n tic sh a rp n o se sh a rk , R hizoprionodon terraenovae: a com parison o f techniques. Copeia 1985(1): 80-85.

Parsons, G .R . 1993a. Age determ ination and grow th of the bonnethead shark Sphyrna tiburo : a com parison o f two populations. M ar. Biol. 117: 23-31.

P a rs o n s , G .R . 1993b. G e o g ra p h ic v a r ia t io n in r e p ro d u c tio n be tw een tw o p o p u la tio n s o f the bonnethead shark, Sphyrna tiburo. Environ. Biol. Fishes 38: 25-35.

Paterson , R .A . 1990. Effects of long-term anti-shark m easu res on ta rg e t an d n o n - ta rg e t species in Q ueensland, A ustralia . Biological Conservation 52: 147-159.

Pauly, D. 1978. A critique o f some lite ra tu re on the grow th, rep roduction and m orta lity o f the lam nid shark Cetorhinus m axim us ( G unnerus ). IC E S Pelagic- Fish Com m ittee paper C .M . 1978/H: 17.

Peres, M.B. and C.M. Vooren. 1991. Sexual development, reproductive cycle, and fecundity o f the school shark Galeorhinus galeus o ff so u th e rn B razil. Fishery Bulletin 89: 655-667.

Phipps, M .J. 1996. Shark Fisheries and Trade in the East Asian Region. T R A F F IC In ternational, C am bridge, U K .

Pollard , D .A . and A .K . Sm ith. In press. Sand tiger shark Carcharias taurus. In: Fow ler et al. in press b.

Pollard , D .A ., M .P. L incoln Sm ith and A .K . Smith. 1996. The biology and conservation status of the grey nurse shark ( Carcharias taurus R afinesque 1810) inN ew South W ales, A ustralia. Aquatic Conservation: M arine and Freshwater Ecosystem s 6: 1-20.

P ra tt, H .L . 1979. R ep ro d u c tio n in the blue shark, Prionace glauca. Fishery Bulletin. 11: 445-470.

P ra tt, H .L . and J.G . Casey. 1983. Age and grow th of the shortfin m ako, Isurus oxyrinchus, using four m ethods. Can. J. Fish. Aquat. Sei. 40 (11): 1944-1957.

37

P ra tt Jr., H.L. and J.G . Casey. 1990. Shark reproductive strategies as a limiting factor in directed fisheries, with a review of H olden’s m ethod of estimating growth- param eters. In: Pratt, H .L. Jr., S.H. G ruber and T. Taniuchi (eds.) Elasmobranchs as living resources: advances in the biology, ecology, systematics, and the status o f fisheries. Pp. 97-109. US D epartm ent of Commerce, N O A A Technical R eport N M FS 90.

Randall, J.E. 1992. Review of the biology of the tiger shark ( Galeocerdo cuvier). Australian Journal o f Marine and Freshwater Research, 43: 21-31.

R ich a rd so n , J .I . and T .H . R ich a rd so n . 1982. A n experimental population model for the loggerhead sea turtle ( Caretta caretta). In: Bjorndal, K. A. (ed. ) Biology and C onservation o f Sea T urtles. P p 165-176. Sm ithsonian Institution Press, W ashington, D.C.

Ripley, W .E. 1946. The biology of the soupfin Galeorhinus zygopterus and b iochem ical studies o f the liver. California Fishery Bulletin 64: 1-96.

Roedel, P.M . and W .E. Ripley. 1950. California sharks and rays. Fish Bull. Calif. Dep. Fish Game, 75, 88pp.

Rose, D.A. 1996. An overview o f world trade in sharks and other cartilaginous fishes. T R A F F IC International, Cambridge, UK.

Rose, D.A. 1998. Shark Fisheries and Trade in the Americas, Volume 1: North America. 143pp. T R A FFIC .

R y lan d , J.S . and T .O . A jay i. 1984. G ro w th and p o p u la tio n dynam ics o f th ree R aja species in C arm arthen Bay, B ritish Isles. J. Cons. int. Explor. M er, 41: 111-120.

Sant, G. and E. Hayes (eds.). 1996. The Oceania R egion’s Harvest, Trade and M anagem ent o f Sharks and other Cartilaginous Fish: An Overview. 70pp. T R A F F IC .

Saunders, M .W . and G .A M cFarlane. 1993. Age and length a t m aturity of the female spiny dogfish, Squalus acanthias, in the S trait o f G eorgia, British C olum bia, C anada. Env. Biol. Fishes 38: 49-57.

Seki, T ., T. Taniuchi, M . Shim izu and H. N akano . U ndated MS. Age, g row th and rep roduction o f the oceanic w h ite tip sh a rk from the n o rth Pacific . N atio n a l R esearch Institu te o f F a r Seas Fisheries, Shimizu, Japan .

S im pfendorfer, C .A . 1993. Age and grow th of the A ustra lian sharpnose shark Rhizoprionodon taylori from N o rth Q ueensland, A ustralia . Environmental Biology o f Fishes. 36: 233-241.

Sim pfendorfer, C.A. In press a. M orta lity estim ates an d d e m o g ra p h ic an a ly s is fo r th e A u s tra l ia n sh a rp n o se sh a rk (R hizoprionodon taylori) from N o rth e rn A ustralia . Fishery Bulletin.

Sim pfendorfer, C. A. In press b. Tiger shark Galeocerdo cuvier. In: Fow ler et al. in press b.

S im pfendorfer, C. A. In press c. W hitespotted wedgefish or g ian t g u ita rfish R hynchobatus djiddensis. In: Fow ler et al. in press b.

S im p fe n d o rfe r , C .A . a n d N .E . M ilw a rd . 1993. U tilisa tion o f a trop ical bay as a nursery area by s h a rk s o f th e fa m ilie s C a rc h a rh in id a e an d Sphyrnidae. Environm ental B iology o f Fishes 37: 337-345.

Sm ale, M .J. In p ress a. O cean ic w h ite tip sh a rk Carcharhinus longimanus. In: Fow ler et al. in press b.

Smale, M .J. In press b. W hitetip reef shark Triaenodon obesus. In: Fow ler et al. in press b.

Sminkey, T .R . 1996. D em ographic analyses o f n a tu ra l and exploited popu la tions of three large coastal sharks. D ocum ent SB-III-8 of the 1996 R ep o rt o f the Shark E valuation W orkshop. June 1996. Southeast Fisheries Science C enter, M iam i, FL. 5 pp.

Sminkey, T .R . and J.A . M usick, 1995. Age and grow th of the sandbar shark, Carcharhinus plumbeus, before and after p o pu la tion depletion. Copeia 4: 871-883.

Sminkey, T.R . and J.A. Musick. 1996. Dem ographic analysis of the sandbar shark, Carcharhinus plumbeus, in the western N orth A tlantic. Fisheries Bulletin 94: 341-347.

Smith Jr., K .L. 1978. M etabolism of the abyssopelagic rattail Coryphaenoides armatus measured in situ. Nature, London 274: 362-364.

S m ith J r ., K .L . and N .O . B row n. 1983. O xygen consum ption of pelagic juveniles and demersal adults o f the deep-sea fish Sebastolobus altivelis, measured at depth. Marine Biologv 76: 325-332.

Smith, S.E., D.W . A u and C. Snow. In press. Intrinsic rebound potentials o f 26 species of Pacific sharks. Marine and Freshwater Research.

Stevens, J .D . 1976. P relim inary results of shark tagging in the n o rth -east A tlantic, 1972-1975. Journal o f the M arine Biological Association o f the United Kingdom 56:929-937 .

Stevens, J.D . 1984. L ife-history and ecology o f sharks a t A ldabra A toll, Ind ian Ocean. Proceedings o f the R oyal Society o f London series B 222: 79-10.

Stevens, J .D . In press a. Porbeagle shark Lam na nasus. In: Fow ler et al. in press b.

S tevens, J .D . In p ress b. S h o rtf in m ak o , Isurus oxyrinchus. In: Fow ler et al. in press b.

Stevens, J .D . In press c. Blue shark Prionace glauca. In: Fow ler et al. in press b.

S tevens, J .D . In p ress d. Schoo l o r T ope sh a rk Galeorhinus galeus. In: Fow ler et al. in press b.

Stevens, J .D . and J.M . Lyle. 1989. The biology of three ham m erhead sharks (Eusphyrna blochii, Sphyrna mokarran and S. lewini) from N o rth e rn A ustralia . Australian Journal o f M arine and Freshwater Research 40 :129-146 .

Sund, O. 1943. E t brugdelbarsel. Naturen, 67: 285-286.Sundstroem , F . and S.H . G ruber. In press. Lem on

shark Negaprion brevirostris. In: Fow ler et al. in press b.

38

T anaka , S., G .M . C ailliet and K .G . Y udin . 1990. Differences in growth of the blue shark Prionace glauca: technique or population? In: P ratt, H .L., S.H. G ruber and T. Taniuchi (eds. ) Elasmobranchs as livingresources: Advances in the Biology, Ecology, Systematics, and the Status o f the Fisheries. N O A A Technical Report N M F S 90. Pp. 177-188.

Tester, A.L. 1969. Cooperative Shark Research and Control Program , Final R eport, 1967-69. University of Hawaii, Honolulu, iv+47 pp., Appendix tables 1-36.

Thorson, T.B. 1982. Im pact of commercial exploitation on sawfish and shark populations in Lake Nicaragua. Fisheries 7(2): 2-10.

T R A F F IC Oceania and T R A F F IC USA. August 1996. A T R A F F IC N etw ork R eport to the CITES Animals Committee on the T R A F F IC N etw ork Global Shark Trade Study. U npublished report. 3pp.

Uchida, S., M. Toda, K. Teshima and K. Yano. 1996. Prelim inary R eport on near-term foetuses from a white shark caught in Kochi, Japan. In: Klimley, A.P. and D .G . Ainley (eds.) Great white sharks: Ecology and Behaviour. Academic Press, Orlando.

van der Eist, R .P. 1979. A proliferation of small sharks in the shore-based N atal sport fishery. Environmental Biology o f Fishes, 29: 349-362.

Van Dykhuizen, G. and H .F. M ollet. 1992. G row th, age estim ation and feeding of captive sevengill sharks, N oto ryn ch u s cepedianus, a t th e M o n te re y Bay Aquarium . Ansi. J. Mar. Freshw. Res. 43(1): 297-318.

W alker, T .I. 1983. Investigations of the gummy shark, M ustelus antarcticus G ünther, from south-eastern A ustralian waters. R eport to Fishing Industry Research Committee. June 1983. In: Proceedings o f the Shark Assessment Workshop, South East Fisheries Committee Shark Research Group. M elbourne, 7-10 M arch 1983. 94 pp. (D epartm ent of Prim ary Industry: Canberra).

W alker, T.I. 1994a. Fishery model of gummy shark for Bass Strait. In: Bishop, I. (ed.) Proceedings o f Resource Technology ‘94 New Opportunities B est Practice. University of M elbourne, M elbourne, 26-30 September 1994. Pp 422-438 . T he C en tre fo r G eo g rap h ic Inform ation Systems & Modelling: The University of M elbourne.

W alker, T.I. 1994b. Stock Assessments of the Gummy Shark, Mustelus antarcticus G ünther, in Bass Strait and off South Australia. In: Hancock, D.A. (ed.) Bureau o f Rural Resources Proceedings No. 14: Fishery Stock Assessm ent, A ustralian Soc ie ty fo r Fish B iology Workshop, Sorento, W estern Australia, 24-25 August1993. Pp 173-187. B ureau o f R u ra l R esources: Canberra.

W alker, T .I. 1996. Stock A ssessm ent R eport. G um m y shark 1995. 33 pp. ( C om piled for the Southern Shark Fishery Assessment G roup ). ( A ustralian G overnm ent P rin ting Service: C anberra).

W alker, T .I. 1998a. C an shark resources be harvested sustainably? A question revisited w ith a review of shark fisheries. M arine and Freshwater Research 49.

W alker, T .I. 1998b. M ercury concen trations in edible tissues o f elasm obranchs, teleosts, crustaceans and m olluscs from so u th -ea s te rn A u s tra lian w aters. Australian Journal o f M arine and Freshwater Research 39: 39-49.

W a lk e r , T .I . In p re ss . G u m m y sh a rk M u ste lu s antarcticus. In: Fow ler et al. in press b.

W alker, P .A . and H .J.L . Heessen. 1996. Long-term changes in ray popu la tions in the N o rth Sea. IC E S Journal o f M arine Science, 53: 1085-1093.

W alker, P.A . and J .R .G . H islop. 1998. Sensitive skates or resilient rays? Spatial and tem poral shifts in ray species com position in the central and north-w estern N o rth Sea betw een 1930 and the presen t day. IC E S Journal o f M arine Science, 55: 392-402.

W a lk e r , T .I . , T . S to n e , T . B a tta g le n e a n d K . M cLoughlin. 1995. F ishery assessm ent report: the sou thern shark fishery 1994. A ustra lian Fisheries M anagem ent A uthority : C anberra.

W eber, M .L. and S.V. F ordham . 1997. M anaging shark fisheries: opportunities fo r international conservation. T R A F F IC In te rn a tio n a l and the C enter fo r M arine C onservation.

W intner, S.P. and G. Cliff. 1996. Age and grow th determ ination of the b lack tip shark, Carcharhinus limbatus, from the east coast o f South A frica. Fish. Bull., U.S. 94: 135-144.

Y udin, K .G . and G .M . Cailliet. 1990. Age and grow th o f the gray sm oothhound, M ustelus californicus, and the brow n sm oothhound, M . henlei, sharks from central C alifornia. Copeia 1990: 191-204.

Zeiner, S.J. and P. W olf. 1993. G row th characteristics and estim ates of age at m atu rity o f two species of sk a tes (R a ja b inocu la ta an d R aja rhina) from M onterey Bay, C alifornia. N O A A Tech. Rep. N M F S 115: 87-99.

Zorzi, G .D . and M .E. A nderson. 1988. R ecords of deep-sea skates, Raja (A m blyra ja) badia G arm an, 1899 and Bathyraja abyssicola (G ilbert, 1896) in the eastern N o rth Pacific, w ith a new key to C alifornia skates. California Fish and Game 74(2): 87-105.

39

The Implications o f Biology’ fo r the Conservation and Management o f Sharks

Annex 1. Summary of the 1994 IUCN Red List Categories and Criteria.This table should be used in conjunction with Table 2, to help explain the basis o f the Red List assessments

applied to various chondrichthyan fishes by the IUCN/SSC Shark Specialist Group.

U se an y of th e A-E c rite r ia CriticallyEndangered

Endangered Vulnerable

A. Declining Populationpo p u la tio n dec line ra te at least us ing e ithe r1. po p u la tio n red u c tio n s o b se rved , es tim a ted , in fe rred , or s u sp e c te d in th e past or

80 % in 10 ye a rs o r 3 g e n e ra tio n s

5 0 % in 10 ye a rs o r 3 g e n e ra tio n s

2 0 % in 10 ye a rs o r 3 g e n e ra tio n s

2. po p u la tio n de c lin e p ro je c t o r s u sp e c te d in th e fu tu re b a se d on:a) d irec t obse rva tio nb) an index of a b u n d a n ce a p p ro p ria te fo r th e taxonc) a de c lin e in a re a of occu p an cy , e x te n t of o ccu rre n ce a n d /o r q u a lity o f hab ita td) ac tua l o r p o ten tia l leve ls of e xp lo ita tione) th e e ffe c ts of in tro d u ce d taxa , hyb rid iza tion , pa tho g e n s , p o llu ta n ts , co m p e tito rs , o r p a ra s ite s

B. Small Distribution and Decline or FluctuationE ithe r e x te n t o f occu rre n ce o r a re a of o ccu p a n cy and 2 o r th e fo llo w in g 3:1. e ith e r se v e re ly fra g m e n te d : (iso la ted s u b p o p u la tio n s w ith a red u ce d p ro b a b ility of reco lo n iza tio n , if one e x tinc t) o r know n to ex is t a t a n u m b e r of loca tions

< 100 km 2< 10 km 2 = 1

< 5 ,000 km 2< 500 km 2 £ 5

< 2 0 ,0 0 0 km 2< 2 ,0 00 km 2 £ 10

2. co n tin u in g de c lin e in a n y of th e fo llo w in g :a) ex ten t o f occu rre n ceb) a re a of o ccu p an cyc) a rea , e x te n t a n d /o r qu a lity of hab ita td) nu m b e r of lo ca tions or s u b p o p u la tio n se) nu m b e r of m atu re ind iv idua ls

an y rate a n y rate a n y rate

3. flu c tu a tin g in any of th e fo llo w in g :a) ex ten t o f occu rre n ceb) a re a of o ccu p an cyc) nu m b e r of lo ca tions or s u b p o p u la tio n sd) nu m b e r of m atu re ind iv idua ls

> 1 o rde r/m ag . < 1 o rde r/m ag . < 1 o rde r/m ag .

C. Small Population Size and DeclineN u m be r of m atu re ind iv idua ls and 1 of th e fo llo w in g 2:1. rap id de c lin e rate

2. co n tin u in g dec line and e ith e r a) fra g m e n te dor b) all in d iv id u a ls in a s in g le su b p op u la tio n

< 250

2 5 % in 3 ye a rs o r 1 g enera tion an y rateall su b -p o p s £ 50

< 2 ,5 00 0

2 0 % in 5 ye a rs or 2 g e n e ra tio n s an y rateall su b -p o p s £ 250

< 10 ,000

10% in 10 ye a rs or 3 g e n e ra tio n s any rateall s u b -p o p s £ 1 ,000

D. Very Small or RestrictedE ithe r1. n u m b e r of m a tu re in d iv id u a ls or2. po p u la tio n is su sce p tib le

< 50(no t ap p lica b le )

< 250(no t ap p lica b le )< 100 km 2 or

< 1 ,000a re a of o ccu p a n cy

no. of lo ca tions < 5

E. Quantitative AnalysisInd ica ting th e p ro b a b ility of e x tinc tion in th e w ild to be at least

50 % in 10 ye a rs or 3 g e n e ra tio n s

2 0 % in 20 ye a rs or 5 g e n e ra tio n s

10% in 100 ye a rs

1

The Implications o f Biology fo r the Conservation and Management o f Sharks

Annex 2. Life-history traits of some chondrichthyan species.1S c ie n t if ic a n d c o m m o n n a m e s

A g e to m a tu r ity (yea rs)

S iz e (c m TL) (a t b ir th , m a tu r ity ,

a n d m a x im u m )

L ife s p a n (years)

L it te rs ize

A n n u a l ra te o f p o p u la t io n

in c re a s e

R e p ro d u c - G e s ta tic t iv e t im e

p e r io d ic ity (m on ths (yea rs )

N o t o r y n c h u s c e p e d i a n u s B roadnose sevengill shark

M :4-5 M :1 1-21 F: 16-20

B irth : 40-45 M at: M :150 F:220

Max: 290-300

M :23-32F :35-49

32

20,82-95(max)

2.6% 2 10-12

S q u a l u s a c a n th ia s S p iny o r p iked dog fish o r spu rdog NW A tla n tic popu la tion (NW Pacific popu la tion)

M :6-14 F :10-12

(F: 12-23)

B irth : 20-30 M at: M :60 F:70 M ax: 100-125

M :35,F :40-50

(70)

2 -15av.4 -9

2 .3 -3 .5 %

(1.7% )

2 (but no resting stage)

18-24

D a la tia s lic h a Kitefin shark

? B irth : 30 M at: M :100 F:120 M ax: M :120 F:160

? 10-16 ? ? ?

S q u a t in a c a l i fo r n ic a Pacific ange lshark

8-13 Birth : 21 -26 M at: M :75-80 M at: F :86-108

M ax: M :1 14 F:152

35 1-11 mean 6

3 .9 -6% 1 10-12

G in g ly m o s to m a c ir r a tu m Nurse shark

? Birth : 27-30 M at: 150 M ax: 425

? 2 0-30 ? ? ?

R h i n c o d o n t y p u s W hale shark

? B irth : 60 M at: F>560 Max: -1 3 7 0

? 300 ? ? ?

C a r c h a r ia s ta u r u s Sand tige r, sp o tte d ragged too th , o r g ray nurse shark

6-128

B irth : 95 -105 M at: 220 M ax: 318

32(NE Pacific)

1-2 4 .6% 2 12

A l o p ia s v u lp in u s Thresher shark

7 Birth : 114-150 M at: M :319 F:376

M ax: 491

? 2-6 7 .2% ? 9

C e t o r h in u s m a x i m u s B asking shark

M: 12-16 F: 20

Birth : 150-170 M :500-700 F:810-980

M ax: 1000-1300

50 5-6 ? 2? >12?

C a r c h a r o d o n c a r c h a r ia s W hite shark

M: 9 -10 F: 12-14

Birth : 120-150 M at: M :350-410 M at: F: 400 -430

M ax 594

36 2-10 4.1% 2? >12?

I s u r u s o x y r in c h u s S hortfin m ako

M: 3 F: 7-8 av. 5

B irth : 60-70 M at: M :195 M at: F:280 M ax: 394

28 4-16 5 .2% 2-3 12-18

L a m n a n a s u s Porbeag le shark

4-8 F: 7.5

B irth : 60-75 M at: M :165 F :152-225

M ax: 300-365

30 1-5 ? 1-3? 9-18?

G a le o r h in u s g a l e u s Tope, schoo l, o r soup fin shark

F: 10-15 M: 8-10

B irth : 30-40 M at: F :134-140 M at: M :125-135

M ax: 155-200

40-60 8-50 (m ean=2 8)

3 .3% 1-3 12

1 M ost o f th e da ta presen ted here are from C om pagno (1984) and S m ith e f a/, in press, w ith upda tes fo r a sm all num ber o f species.

2

The Implications o f Biology’ fo r the Conservation and Management o f Sharks

D istribution cosmopolitan, pelagic,wide-ranging, demersal

regional, country endem ic, localized,

restricted

H abita t inform ation insular, oceanic, pupping/

bathyal (>200m), nursery coastal (shore-200m), grounds

reef, mangrove, (estuarine, estuarine near-/offshore)

Fisheries pressure Directed Incidental

(high, some, (high, low, none) some,

low, none)

References

w ide -rang ing , dem ersa l te m pe ra te w a te rs

coasta l es tuarine - h igh high C om pagno in press, Ebert 1990, nearshore Ebert 1989, Van D ykhuizen &

M olle t 1992

cosm op o lita n , dem ersa l coasta l o ffsho re high high Fordham in press, Gauld 1979, Jensente m pera te to 1965, Jones & Geen 1977, Ketchen

su b a rc tic w a te rs 1975, N a m m a cke fa /. 1985, NOAA1998, Saunders & M cFarlane 1993

w ide -rang ing , w arm tem pe ra te to trop ica l w ate rs

dem ersa l bathya l bathya l high in som e

loca tions

high in som e

loca tions

C om pagno & C ook in p ress

loca lized, co ld to warm

te m pe ra te w a te rs

dem ersa l coasta l coasta l high high C a illie t in press, C a illie t e f a /.1992, Natanson & C a illie t 1986, 1990.

reg iona l (A tlan tic and E. Pacific)

dem ersa l coasta l nearshore low low C astro 1997, C arrie r 1991, C la rk & von S ch m id t 1965

cosm opo litan , w arm tem pe ra te

and trop ica l

pe lag ic coas ta l-o ce a n ic ? low low Joung e t a l. 1996, N orm an in press.

w ide -rang ing , te m pera te to su b -tro p ica l

dem ersa l coasta l nearshore-estuarine

low high Branstetter & M usick 1994, G ilmore 1993, G ilm ore e f a l. 1983, G oldm an 1998, Po lla rd e f a l. 1996, Po lla rd & S m ith in press. S m inkey 1996.

cosm opo litan , w arm w aters

pe lag ic co a s ta l-ocean ic inshore high? som e? G oldm an in press.

w ide -rang ing , te m pera te to boreal w ate rs

pe lag ic coasta l o ffshore? som e som e Fow ler in press, Kunzlik 1988, Pauly 1978, Parker & S to tt 1965, S und 1943.

w ide -rang ing , te m pera te to boreal w ate rs

pe lag ic coas ta l-o ce a n ic p rob a b lycoasta l

low (high in som e tro p h y

fisheries)

low (high in beach ne tting areas)

Caillie t e f a l. 1985, Fergusson 1996, Fergusson e f a l. in press, Francis 1996, U ch ida e f a l. 1996.

cosm opo litan , trop ica l, s u b ­trop ica l and tem pera te

pe lag ic oceanic,som e tim es

coasta l

p robab lycoasta l

high [in som e

recrea tiona l fisheries]

high Caillie t & M olle t 1997,C a illie t e f a l. 1983, C liff e f a l. 1990, M o lle t e t a l. 1997, Pra tt &C a se y i 983, S tevens in press.

w ide -rang ingdem ersa l

pe lag ic and oceanic

coasta l and ocean ic

o ffshore high high Aasen 1963, Ellis & S h a c k le y 1995, G auld 1989, S tevens in press.

w ide -rang ingsom etim es

pe lag ic

dem ersa l, (but dow n to 800 m)

coasta land

estuarine

nearshore high som e Capape & M ellinger 1988,G rant e t a l . 1979, O lsen 1954, Peres & Vooren 1991, R ipley 1946,S tevens in press, W a lk e re i a/. 1995.

3

The Implications o f Biology fo r the Conservation and Management o f Sharks

Annex 2 continuedScientific and com m on names

Age to Size (cm TL) Life span L itter Annual rate R eproduc- Gestation m aturity (at birth, (years) size of popula tion five tim e(years) m aturity, increase period ic ity (months)

and maximum) (years)

M u s t e l u s a n ta r c t i c u s G um m y shark

M u s t e l u s h e n le i Brow n sm oo thhound

4 -5 B irth ; M :30-40M at: F:85 M :80

Max: 175

2 -3 B irth : 19-21M at: M :51 -63 F :52-66

M ax: 95

16 10-38(mean=14)

15 3-5

12% annua lly in 11-12 W . A ustra lia

2 yea r in Bass S tra it

13.6% 1 10-11

C a r c h a r h in u s fa lc i fo r m is M : 10S ilky sha rk F:>12

Birth : 76-87 M at: M :187-225 M at: F :213-245

Max: 330

M :>20F:>22

2-15 1-2 12

C a r c h a r h in u s l e u c a s Bull shark

6-8 o r 15

Birth : 56-81 M at: 200

M ax: 300-320

M: 16 F: 12-27

1-13 2 .7% 10-11

C a r c h a r h in u s l im b a tu s M: 4-5B la ck tip shark F: 6-8

B irth :53-65 M at: M :130 F:>155 M ax: M :175 F:193

1 0 - 1 Í 2 -44-7

2 .2 -13 .6%5.6%

11-12

C a r c h a r h in u s l o n g im a n u s O ceanic w h ite tip shark

4 -5 B irth : 60-65M at: F: 180-200 M :175-195

Max: 310

22 1-14 6.9% 12

C a r c h a r h in u s m e l a n o p t e r u s B la ck tip ree f shark (Eastern hem isphere)

B irth : 30-35 M at: 95 -110

M ax: 140-180

2-4 1 o r 2o r 10-11

o r ? 16

C a r c h a r h in u s o b s c u r u s M: 19D usky shark F: 21

B irth : 80-100 M at: F:280 M ax: 365

4 0 -50 3 -14 2 .8%(mean 607) 2%

2 or 3 12 o r 22-24

C a r c h a r h in u s p l u m b e u s S andba r shark

13-16 B irth : 60-65[29 in M at: M: 170 F:>180

ano the r s tudy] M ax> 239 (in USA)

25-35 8-13 2 .2 -11 .9% 3 .4% , o r 5 .2%

if m at=29 years]

9-12

G a le o c e r d o c u v i e r T iger shark

-10 B irth : 59-90M at: M :226-290 F :250-350

M ax:450- 600

50 10-80 av. 35

4 .3% prob a b ly 2 y rs 12-16

G ly p h is s p .B orneo rive r shark

N e g a p r io n b r e v ir o s tr i s Lem on shark

11-13 B irth : 60 M: 224 (mat) M at: M :224 F:239

M ax: M :>279 F:>285

27 4-17 1.2%

P r io n a c e g la u c a Blue shark

F:5-7M :4-6

B irth : 35-50 M at: M :180-218 M at: F: 180-220

Max: 383

20 40 av 6 .25% fem ales? 9-12(4-135) m ales annually?

R h i z o p r io n o d o n t e r r a e n o v a e A tla n tic sha rpnose shark

3 -4 B irth : 30-35M at: M :80 -85 F :85-90

Max: 110

10 4-61-7

4 .5% annual 10-128 .8 %

The Implications o f Biology’ fo r the Conservation and Management o f Sharks

D istributioncosmopolitan, w ide-ranging,

regional, country endem ic, localized,

restricted

pelagic,demersal

H abita t inform ation Fisheries pressure Referencesinsular, oceanic, pupping/ Directed Incidental

bathyal (>200m), nursery (high, some, (high,coastal (shore-200m), grounds low, none) some,

reef, mangrove, (estuarine, low, none)estuarine, fresh near-/offshore)

endem ic(tem perateAustra lia)

loca lized

dem ersa l

dem ersa l

coasta l

coasta l

high

m od

high? Lenanton e t a ! . 1990, M ou lton e t a ! .1992, W a lke r 1996, 1983, 1994a, b, & in press.

m od Y ud in & C aillie t 1990.

w ide -rang ing in pe lag ic co a s ta l-te m pera te and ocean ictrop ica l w a ters

o ffsho re high high Bonfil 1990 & in press,B onfil e t a ! . 1993, B rans te tte r 1987b

w ide -rang ing in pe lag ic sub tro p ica l to

trop ica l w a te rs

co sm o p o lita n in w a rm -te m p e ra te to trop ica l w ate rs

pe lag ic

cosm o p o lita n pe lag ic

coasta l in to estuarine estuaries and

freshw a te r

coasta l

oceanic;insu lar

estuarine

high high Burgess e f a l. in press, B rans te tte r & S tiles 1987

high low B rans te tte r 1987a, Burgess &B rans te tte r in press, C astro 1996, Dudley & C liff 1993, K illam & Parsons 1989, W in tn e r & C liff 1996.

h igh high B ackus e f a l. 1956, Seki e f a l. (MS),Sm ale in press.

w idesp read dem ersa l insu la r (reefs) insu lar h igh high Heupel in press, Last & S tevens 1994, S tevens 1984.

w ide -rang ing in coa s ta l-su b -tro p ica l and pe lag icte m pe ra te oceans

w ide -rang ing trop ica l and

te m pe ra te oceans

pe lag ic

co sm o p o lita n in coa s ta l- trop ica l and pe lag ic

su b tro p ica l w ate rs

coasta l

coasta l,oceanic

coasta l

o ffsho re in high A us tra lia (in USA &

inshore USA Austra lia)

nearshore high

w id e -rang ing , loca lly m ay en te r high

estuarine areas

high B rans te tte r & Burgess 1996,Cam hi e t a l. in press, C ortés in press, G o ldm an 1998, Natanson e t a l. 1995,

som e, Casey & Natanson 1992, Casey e f al. m odera te 1985, S m inkey & M us ick 1995, 1996,

M us ick in press.

low B rans te tte r e f a l. 1987, C la rk & von S ch m id t 1965, De C ro s ta e fa /. 1984, Randall 1992, S im p fe n do rfe r in press, S m inkey 1996, Teste r 1969.

res tr ic te d to loca lised rivers in Borneo?

regional dem ersa l

dem ersa l

coasta l, insu lar and reefs

freshw a te r-estuarine

nearshore

low low -m o d e ra te (bycatch)

h igh high B row n & G ruber 1988, S undstroem & G ruber in press.

cosm o p o lita n pe lag ic oceanic , o ffsh o re low high A m orim 1992, C a illie t e f a l. 1983, som e tim es C astro & M eju to 1995, Hazin 1993,

coasta l N akano 1994, P ra tt 1979, S tevens1976 & i n press, Tanaka e f a l. 1990

w ide -rang ing in dem ersa l warm tem pera te to trop ica l A tlan tic

coasta l estuarine high high B ranste tte r, 1987b,C ortés 1995, in p ress a, b, Parsons 1983, 1985,

5

The Implications o f Biology fo r the Conservation and Management o f Sharks

Annex 2 continuedScientific and com m on names

Age to m aturity (years)

Size (cm TL) (at birth, maturity,

and maximum)

Life span L itter (years) size

Annual rate R eproduc- Gestation of popula tion tive tim e

increase period ic ity (months) ________________ (years)____________

T r ia e n o d o n o b e s u s W h ite tip reef shark

5 o r B irth : 52 -60 M at: 105 Max: 170

16-25 1-52-3

4 .9% >5?

S p h y r n a le w in i M : 4 -10S ca lloped ham m erhead F :4 -1 5

Birth : 31-55 M at: M: 140-280 M at: F: 150-300 M ax: 329-420

35 15-4012-38

2 .8 % 9-12

S p h y r n a t ib u r o B onnethead shark

F: 2 -3 B irth : 35-40M: 3 M at: M :68-85 F :80-85

M ax: M :124 F:150

12 4-16 0 .01-0 .27 annual? ?

P r is t is m i c r o d o n G rea ttoo th o r freshw a te r saw fish

700 (max)

P r is t is p e c t i n a t a S m a lltoo th o r w id e saw fish

760 (max) 15-20

R h y n c h o b a t u s d j i d d e n s i s G iant gu ita rfish

B raz ilian g u ita rfis h

R h i n o b a t o s h o r k e l i i

F: 7 -9

M: 5-6

M: 110 (mat) > 300 (max)

M at: 9 0 -1 2 0 4-12 11-12

B a th y r a ja a b y s s i c o la D eepsea skate

R a ja (R a ja ) c la v a ta T ho rnback ska te o r ray

9-12

M: 110 (mat)

M: 69 (mat) F: 72 (mat)

? ?(eggs)

M: 36 -43 52 eggsF: 39 -46 /ye a r

0 o r less in N orth Sea

annual

n/a

n/a

R a ja (D ip tu r u s ) b in o c u la ta M: 8-11 Big ska te F: 12

B irth :M at: M :1 0 0 -1 10 F:130

M ax: 168-240

1-7 em bryos pe r egg case

n/a

R a ja b a t i s C om m on ska te

11 Birth: 21-22 M at: M :125

M ax: 254

50 40 eggs annual? n/a

R a ja (D ip tu r u s ) r h in a M: 7-8Longnose ska te F: 8-10

B irth :M at: M :60 F:>70

Max: 137

n/a

B a t ray

M y l i o b a t i s c a l i fo r n ic a

M :4, F:5 B irth 20 (DW)

M at: M :60 F:88 (DW)

M ax 180 (D W -d isk w id th )

10M , 25F 2 -5 -12

H im a n tu r a c h a o p h r a y a G iant freshw a te r s ting ray o r w h ip ray

B irth :M at: 100 (disk w id th) Max: 200 (d isk w id th )

6

The Implications o f Biology’ fo r the Conservation and Management o f Sharks

D istribution cosmopolitan, pelagic,wide-ranging, demersal

regional, country endem ic, localized,

restricted

H abita t inform ation insular, oceanic, pupping/

bathyal (>200m), nursery coastal (shore-200m), grounds

reef, mangrove, (estuarine, estuarine near-/offshore)

Fisheries pressure Directed Incidental

(high, some, (high, low, none) some,

low, none)

References

w ide -ra n g in g dem ersa l (in Indo-P acific)

coasta l nearshore som e high A nderson & A hm ed 1993,F ourm ano ir 1961, Last & S tevens 1994, Sm ale in press.

w ide -ra n g in g in w arm tem pe ra te to trop ica l w ate rs

pe lag ic coas ta l-o ce a n ic nearshore high high B rans te tte r 1987b, K o tas in press, S tevens & Lyle 1989.

regional dem ersa l coasta l and reefs

high C arlson & P a rsons 1997, C o rté s in p ress , C o rté s & P a rsons 1996, P a rsons 1993a, 1993b.

loca lized in tro p ic s

w ide -rang ing (disjunct)

w ide -rang ing in trop ica l w a te rs

dem ersa l

dem ersa l

dem ersa l

reg iona l dem e rsa l

freshw a te r

coasta l and freshw a te r

coasta l

high

high

high

co a s ta l ne a rsh o re h igh

high C om pagno & C ook in press, Last & S tevens 1994.

high A dam s in press, B ige low & S ch roede r 1953.

high S im p fe n do rfe r in press, Last & S tevens 1994.

h igh Lessa 1982, L e s s a e fa / . 1986,

Lessa & V o o re n in p ress.

regional dem ersa l

w ide -ra n g in g in dem ersa l te m pe ra te w a te r

ba thya l ? none som e(too rare)

coasta l es tuarine - h igh highnearshore

C o o k e f a/, in p ress,Z orz i & A n d e rso n 1988.

B rander & Pa lm er 1985, C apape 1977, Ellis & S h a c k le y 1995, Ellis in press, Ho lden 1975, Holden & V ince 1973, N o ttage & Perkins 1983, Ryland & A jayi 1984.

Regional dem ersa l (NE Pacific)

reg iona l, boreal dem ersa l to coo l tem pe ra te

(NE A tlan tic )

Regional dem ersa l (NE Pacific)

coasta l nearshore high and o ffshore

coasta l

coasta l nearshore and o ffshore

high

high

high E llis & D u lvey in p ress , M artin & Zorz i1993, Z e in e r & W o lf 1993, D eLacy & C hapm an 1935, H itz 1964.

high E llis & W a lke r in p ress, Du B u it 1972& 1976, B ra n d e r 1981, Fahy 1991.

high Z e in e r & W o lf 1993.

w e s t c o a s t dem ersa l

USA

co a s ta l es tu a rie s so m e C a illie t in p ress,

M artin & C a illie t 1988 a & b.

loca lized dem ersa l freshw a te r- freshw a te r som e som e C om pagno & C ook in press,estuarine Last & S tevens 1994.

7

The Implications o f Biology fo r the Conservation and Management o f Sharks

ReferencesAasen, O. 1963. Length and growth of the porbeagle (lam na

nasus Bonnaterrei in the northwest Atlantic. Fiskeridir. Skr., 13(6): 20.

Adams, W.F. In press. Smalltooth or wide sawfish Pristis pectinata. In: Fowler, S.L., M. Camhi, A. Bräutigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status o f the chondrichthy an fishes. IUCN/ SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Alverson, D.L., M.H. Freeman, S.A. Murawski and J.G. Pope. 1994. A globed assessment o f fisheries bycatch and discards. FAO Fisheries Technical Paper no. 339. Rome: Food and Agriculture Organization of the United Nations. 233 pp.

Amorim, A.F 1992. Estudo da biologia, pesca e reproducao do cacao azul, Prionace glauca L. 1758, capturado no sudeste e sul do Brasil. Doctor Thesis, Universidade Estadual Paulista, Rio Claro, Sao Paulo, Brazil, 1992,176 pp.

Anderson, E.D. 1990a. Estimates of large shark catches in the western Atlantic and Gulf of Mexico, 1960-1986. In: Pratt, H.L. Jr., S.H. Gruber andT Taniuchi (eds ),Elasmobranchs as living resources: advances in the biology’, ecology’, systematics, and the status o f fisheries. Pp. 443-54. U.S. Department of Commerce, NOAA Technical Report NMFS 90.

Anderson, E .D. 1990b. Fishery models as appliedto elasmobranch fisheries In: Pratt, H.L. Jr., S.H. Gruber andT Taniuchi (eds), Elasmobranchs as living resources: advances in the biology’, ecology’, systematics, and the status o f fisheries. Pp. 473-84. U.S. Department o f Commerce, NOAA Tech. Report NMFS 90.

Anderson, R.C. andH. Ahmed 1993. The Shark Fisheries o f the Maldives. Ministry of Fisheries and Agriculture, Republic of Maldives and Food and Agricultural Organization of the United Nations. 76 pp.

Anon. 1995. Report ofthe Study Group on ElasmobranchFishes. ICES CM 1995/G: 3. International Council forthe Exploration of the Sea. Copenhagen, Denmark.

Anon. 1997. Biological and trade status of sharks. Report o f the CITES Animals Committee (Pursuant to Resolution Conference 9.17). does this have a cites reference no.?

Arocha, F. 1997. The reproductive dynamic s of swordñshXiphias gladius L. and management implications in the northwestern Atlantic. Dissertation University of Florida, Coral Gables, FL.

Auster, P.J. and R.W. Langton. 1998. The effects of fishing. MS prepared under contract to the American Fisheries Society. Bethesda, Maryland, 57pp.

Backus, R.H., S. Springer, andE. L. Arnold. 1956. Acontribution to the natural history of the white-tip shark, Pterolamiops longimanus (Poey) Deep-Sea Research 3:178-188.

Beamish R.J. and G.A. McFarlane. 1987. Current trends in age determination methodology. In: R.C. Summerfelt and G.E. Haii, eds, The Age and Growth o f Fish. Pp. 15-42. Iowa State Univ. Press, Ames, USA.

Beirow, S. D., and I Ieardman. 1994. The basking shark ( 'etorhinus

maximus (Gunnerus) in Irish waters - patterns of distribution and abundance. Proc. Roy. Irish Acad. 94B, 2:101-107.

Beverton, R.J.H. 1990. Small marine pelagic fish and the threat of fishing : are they endangered? J. o f Fish Biology’ 3 7 ( Suppl. A): 15-16.

Bigelow, H. B. and W. C. Schroeder. 1953. Sawfishes, guitarfishes, skates, rays, and chimaeroids. In: J. Tee Van, C.M. Breder, A.E. Parr, W.C. Schroeder and L.P.Schultz (Eds.), Fishes ofthe western North Atlantic. 1(2): 1-514. Sears Foundation for Marine Research, Yale University. New Haven, CT (USA).

Bonfil, R., 1990. Contribution to the fisheries biology ofthe silky shark Carcharhinus falciformis (Bibron 1839) from Yucatan, Mexico. M.S. Thesis, University ofWales, Bangor. 77 pp.

Bonfil, R. 1994. Overview’ o f world elasmobranch fisheries. FAOFisheries Technical Paperno. 341. Rome: FAO. 119pp.

Bonfil, R. In press. Silky shark Carcharhinus falciformis. In: Fowler, S.L., M. Camhi, A. Bräutigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status o f the chondrichthy an fishes. IUCN/SSCSharkSpecialist Group. IUCN, Gland, Switzerland and Cambridge, UK

Bonfil, R., R. MenaandD. de Anda. 1993. Biological parameters of commercially exploited silky sharks, Carcharhinus falciformis, from the Campeche Bank, Mexico. In: S. Branstetter (ed.). Conservation Biology’ o f Elasmobranchs. NOAA Technical Report NMFS 115. US Department of Commerce.

Brander, K. 1981. Disappearance of common skate Raja batis from Irish Sea. Nature, 290:48-49.

Brander, K. andD. Palmer. 1985. Growth rate ofRaja clavata in the Northeast Irish Sea../. Coris. int. Explor: Mer,42:124-128.

Branstetter, S. 1987a. Ageand growth ofnewbom sharks heldin laboratory aquaria, with comments on the fife history of the Atlantic sharpnose shark, Rhizoprionodon terraenovae. Copeia 1987(2):291-300. THIS ONE IN TEXT

Branstetter, S. 1987b. Age growth and reproductive biology of the silky shark, Carcharhinus falciformis, and the scalloped hammerhead, Sphyrna lewini, from the northwestern Gulf of Mexico. Um’. Biol. Fishes 19:161-173.

Branstetter, S. 1987c. Age and growth estimates for blacktip, Carcharhinus limbatus, and spinner, C. brevipinna, sharks from the northwestern GulfofMexico. Copeia 1987(4):964-974.

Branstetter, S. 1990. Early life-history implications of selected carcharhinoid and lamnoid sharks of the northwest Atlantic. In: Elasmobranchs as living resources: advances in the biology’, ecology: systematics, and the status o f fisheries. (H.L. Pratt, Jr., S.H. Gruber and T Taniuchi, eds.), pp. 17-28. U.S. Department of Commerce, NOAA T echnical Report NMF S 90.

Branstetter, S. 1997. Burning the candle at both ends. Shark News (the Newsletter o f the IUCN Shark Specialist Group), 9: p 4.

Branstetter, S. and Burgess, G.H. 1996. Commercial Shark F ishery Observer Program. Characterization and comparisons ofthe directed commercial shark fishery in the eastern Gulf of

The Implications o f Biology’ fo r the Conservation and Management o f Sharks

Mexico and off North Carolina through an observer program. Final Report, MARFIN Award NA47FF0008, 33 p. + 11 tables + 20 figs.

Branstetter, S. andMusick, J. A. 1994. Age and growth estimates for the sand tiger shark in the Northwestern Atlantic Ocean. Transactions ofthe American Fisheries Society’ 123,242-254.

Brandstetter, S. andR. Stiles. 1987. Age and growth estimates of the bull shark, Carcharhinus lateas, from the northern Gulf ofMexico. Environ. Biol. Fishes. 20(3): 169-181.

Branstetter, S, Musick, JA, and Colvocoresses, JA. 1987. A comparison ofthe ageandgrowthofthe tiger shark, Galeocerdo cuvieri, from off Virginia and from the northwestern Gulf of Mexico. US National Marine Fisheries Service Fishery Bulletin 85,269-79.

Brown, C.A. and S.H. Gruber. 1988. Age assessment of the lemon shark, Negaprion brevirostris, using tetracycline validated vertebral centra. Copeia 1988(3): 747-753.

Bryant, D., L. Burke, J. McManus, M. Spalding. 1998. Reefs at Risk. A Map-based Indicator of Threats to the World's Coral Reefs. World Resources Institute, International Center for Living Aquatic Resource Management, World Conservation Monitoring Centre, and United Nations Environment Programme. 56pp.

Burgess, G.H. and S. Branstetter. In press. Blacktip shark Carcharhinus limbatus. In : Fowler, S.L., M. Camhi, A. Bräutigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status o f the chondrichthy an fishes. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Burgess, G.H., C.A. Simpfendorfer, and A. Amorim. In press. Bull shark Carcharhinus leucas. In : Fowler, S.L., M. Camhi, A. Bräutigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status o f the chondrichthy an fishes. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Cailliet, G.M. In press. Bat ray Myliobatis californica. In: Fowler, S.L.,M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status ofthe chondrichthy an fishes. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Cailliet, G.M. In press. Pacific angel shark Squatina californica. In: Fowler, S.L., M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status o f the chondrichthy an fishes. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Cailliet, G.M., Martin, L.K, Harvey, J.T., Kusher, D. and Welden, B .A. 1983. Preliminary studies on the age and growth of blue, Prionace glauca, common thresher, Alopias vulpinus, and shortfin mako, Isurus oxyrinchus, sharks from Califormian waters. In: E.D. Prince and L.M. Pulos (eds), Proceedings of the international workshop on age determination of oceanic pelagic fishes: Tunas, billfishes, and sharks, p. 179-188. NOAA Technical Report, NMFS 8.

Cailliet, G.F., and H.F. Mollet. 1997. Preliminary demographic

analysis ofthe short tin mako, Isurus oxyrinchus. Program and Abstracts o f 77th Annual Meeting of American Society of Ichthyology and Herpetology, pp. 88.

Cailliet, G.M., H.F. Mollet, G.G. Pittenger, D. Bedford, and L. J. Natanson. 1992. Growthand demography ofthe Pacificangel shark (Squatina californica), based upon tag returns off California. Australian J. Marine. Freshwater Res. 43:1313- 1330.

Cailliet, G.M., Natanson, L.J., Weldon, B.A., & Ebert, D.A.1985. Preliminary studies on the age and growth of the white shark Carcharodon carcharias, using vertebral bands. South. Calif. Acad Sei,, Memoirs 9: 49-60

Cailliet, G.M., R.L. RadtkeandB.A. Welden. 1986. Elasmobranch age determination and verification: a review. In: Indo-Pacific Fish Biology’: Proceedings o f the Second International Conference on Indo-Pacific Fishes. (T. Uyeno, R. Arai, T. T aniuchi andK. Matsuura, eds. ), T okyo : Ichthyological Society of Japan, pp. 345-360.

Camhi, M.D. 1993. The role of nest site selection in loggerhead ( Caretta caretta ) sea turtle nest success and sex ratio control. Dissertation. Rutgers University, New Brunswick, NJ. 251 pp.

Camhi, M. 1998. Sharks on the line: a State-by-State analysis o f sharks and their fisheries. National Audubon Society Living Oceans Program. USA.

Camhi, M., J. Musick, and C. Simpfendorfer. In press. Dusky shark Carcharhinus obscurus. In: Fowler, S.L., M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status ofthe chondrichthy an fishes. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Capape, C. (1977). Contribution a la biologie des Rajidae des cotes tunisiennes X. Raja clavata Linne, 1758: Etude complementaire de la fécondité. Bull. Off. natn. Pech. Tunisie, 1(2): 169-172.

Capape, C., and Mellinger, J. 1988. Nouvelles données sur la biologie de la reproduction du milandre, Galeorhinus galerr s (Linne, 1758), (Pisces, Triakidae) des cotes tunisiennes. Cah. Biol. Mar. 29:135-146.

Carlson, J.K., and G.R. Parsons. 1997. Age and growth of the bonnethead shark, Sphyrna tiburo, from northwest Florida with comments on clinal variation. Em. Biol. Fish. 50:331-341.

Carrier, J.C. 1991. Growth and aging: life history studies of the nurse shark, pp. 68-69. In: Gruber, S.H. (ed.). Discovering Sharks. Amer. littoral Soc. sp. puhi. 14.

Casey, J. and R. Myers 1998. Near extinction of a large, widely distributed fish. Science 281:690-692.

Casey, J.G. and L.J. Natanson. 1992. Revised estimates of age and growth of the sandbar shark (Carcharhinus plumbeus) from the western North Atlantic. Can. J. Fish. Aquat. Sei, 49: 1474-1477.

Casey, J.G., Pratt, H.L. Jr., and Stillwell, C.E. 1985. Age and growth of the sandbar shark (Carcharhinus plumbeus) from the western North Atlantic. CanJFish,Aquat,Sci, 42:963-975.

Castro, J.A. and Mejuto, J. 1995. Reproductive parameters of blue shark, Prionace glauca, and other sharks in the Gulf of

9

The Implications o f Biology fo r the Conservation and Management o f Sharks

Guinea. Marine and Freshwater Research 46,967-73.Castro, J.1.1993. The sharknursery ofBulIs Bay, SouthCarolina,

with a review ofthe shark nurseries of the southeastern coast ofthe United States. Env. Biol. Fishes 38:37-48.

Castro, J.I. 1996. Biology of the blacktip shark, Carcharhinus limbatus, off the southeastern United States. Bull. Mar. Sei. 59: 508-522.

Castro, J.I. 1997. Reproductive biology of the nurse shark, Ginglymostoma cirratum. Programme and Abstracts of the 77thAnnualMeeting ofthe American Society oflchthyologists and Herpetologists.

Chang, W.-B., M.-Y. Leu and L.-S Fang. 1997. Embryos of the whale shark Rhincodon ripus: early growth and size distribution. Copeia 1997 (2): 444-446.

Chen, G.C.T. K.M. Liu, S.J. Joung. andM. J. Phipps. 1996. Shark F isheries and T rade in T aiwan. Unpublished TRAFFIC report. 48pp.

Chen, H.K. 1996. Shark fisheries and trade in sharks and shark products in Southeast Asia. TRAFFIC International, Cambridge, UK.

Clark, E., and K. von Schmidt. 1965. Sharks of the central Gulf coast of Florida. Bull. Mar. Sei. 15(1 ):13-83.

Clemens, W.A., and Wilby, G.V. 1961. Fishes o f the Pacific Coast, o f Canada. Fisheries ResearchBoardofCanada. Bulletin No. 68.

Cliff, G. and S.F .J. Dudley. 1992. Protection against shark attack in South Africa, 1952-1990. Aust. J. Mar. Freshw. Res. 43: 263-272.

Cliff, G., Dudley, S.F .J., andDavis, B. 1990. Sharks caught in the protective gili nets ofNatal, South Africa. 3. The shorfinmako shark Isurus oxyrinchus (Rafinesque). South African Journal o f Marine Science, 9 : 115-126.

Compagno, L .J.V. 1984. Sharks o f the world. An annotated and illustrated catalogue o f shark species biown to date.FAO Fish Svnop. 125, part 1:1-249, part II: 251-655.

Compagno. L.J.V. In press. Broadnose sevengill shark Notorynchus cepedianus. In: Fowler, S.L., M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status o f the chondrichthyan fishes. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Compagno, L.J.V. In press. World List of Chondrichthyan Fishes. In: Fowler, S.L., M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status o f the chondrichthyan fishes. IUCN/ SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Compagno, L.J.V., and S.F. Cook. 1995. The exploitation and conservation of freshwater elasmobranchs: status of taxa and prospects for the friture. In: Oetinger, M.I., and G.D. Zorzi, eds., The biology o f freshwater elasmobranchs. Journal o f Aquariadture and Aquatic Sciences, 7: 62-90.

Compagno, L.J.V. and S.F. Cook. 1996. Status of the kitefin shark Dalatias licha. SharkNev’s (the Newsletter ofthe IUCN Shark Specialist Group), 7: 4.

Compagno, L.J.V. and S.F. Cook. In press. Giant freshwater stingray Himantura chaophrya. In: Fowler, S.L., M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status o f the chondrichthyan fishes. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Compagno, L.J.V. and S.F. Cook. In press. Great-tooth or freshwater sawfish Pristis microdon. In: Fowler, S.L., M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status o f the chondrichthyan fishes. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Compagno, L J. V. and S.F. Cook. In press. Kitefin shark Dalatias licha. In: Fowler, S.L., M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status o f the chondrichthyan fishes. IUCN/ SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Compagno, L.J.V. and S.F. Cook. In press. Pristiformes, sawfishes: Introduction. In: Fowler, S.L., M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status o f the chondrichthyan fishes. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Cook, S., L. Compagno, and M. Oetinger. 1995. Status of the largetooth sawfishPrótóperotteti. Shark News (the Newsletter ofthe IUCN Shark Specialist Group), 4: 5

Cook, S.F., L.J.V. Compagno, and M. I. Oetinger. In press. Largetooth sawfish Pristis perotteti. In: Fowler, S.L., M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status o f the chondrichthyan fishes. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Cook, S.F., G. Zorzi and L.J.V. Compagno. In press. Deepsea skate Bathyraja abyssicola. In: Fowler, S.L., M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status o f the chondrichthyan fishes. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Cortés, E. 1995. Demographic analysis ofthe Atlantic sharpnose shark, Rhizoprionodon terraenovae, in the Gulf of Mexico. Fishery Bulletin 93:57-66.

Cortés, E. In press a. Demographic analysis as an aid in shark stock assessment and management. Fisheries Research. CITED IN TEXT AND IN APPENDICES

Cortés, E. In press b. Atlantic sharknose shark Rhizopriodon terraenovae. In: Fowler, S.L., M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status ofthe chondrichthyan fishes .IUCN/ SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Cortés E. In press c. Bonnethead shark Sphyrna tiburo. In: Fowler, S.L., M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status ofthe chondrichthyanfishes. IUCN/SSC Shark Specialist

10

The Implications o f Biology’ fo r the Conservation and Management o f Sharks

Group. IUCN, Gland, Switzerland and Cambridge, UK.Cortés, E., and G.R Parsons. 1996. Comparative demography of

two populations of the bonnethead shark (Sphyrna tiburo). Ccm. J. Fish. Aquat. Sei. 53:709-718.

Crowder, L.B., D.T. Crouse, S.S. Heppell, and T.H. Martin.1994. Predicting the impact o f turtle excluder devices on loggerhead sea turtle populations. Ecological Applications 4(3): 437-445.

Darling, J.D. & Keogh, K.E. (1994). Observations of basking sharks Cetorhinus maximus in Clayoquot Sound, British Columbia. Canadian Field Naturalist 108,199-210.

Dayton, P.K. 1998. Reversal of the burden of proof in fisheries management. Science 279: 821-822.

De Crosta, M.A., Taylor, L.R., and Parrish J.D. 1984. Age determination growth and energetics of three species of carcharhinid sharks in Hawaii. In: Proceedings o f the Second Symposium on Resource Investigations in the Northwestern Hawaiian Islands. Vol. 2, pp 75-95. (University o f Hawaii Sea Grant Miscellaneous Report 84-01.)

DeLacy, A.C. and W.M. Chapman. 1935. Notes on some elasmobranchs of Puget Sound, with descriptions of their egg cases. Copeia, 1935(2):63-67.

Didier, D. in press. Chimaeroid fishes. In: Fowler, S.L., M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status o f the chondrichthyan fishes. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

DuBuit,M.H. 1972. Etude du stock de raies de la mer Celtique. Trav. lab. Biol. Halieutique, Université de Rennes, 6:13-31.

Du Buit, M.H. 1976. Age et croissance de Raja batis et de Raja nae vi is en Mer ( cltiq uc../. Cons. int. Explor. Mer, 37(3):261- 265.

Dudley, S..FJ. andG Cliff 1993. Sharks caught in the protective gili nets off Natal, South Africa. 7. The blacktip shark, C. flimbatus (Valenciannes). S. Afi: J. Mar. Sei. 13:23 7-254.

Dulvey, N. in prep.Ebert, D.A. 1989. Lifehistory ofthe sevengill shark, Notorynchus

cepedianus Peron, in two Northern California Bays. Calif Fish Game 75(2): 102-112.

Ebert, D.A. 1990. The taxonomy, biogeography and biology of cow and frilled sharks (Chondrichthyes: Hexachiformes). PhD thesis, Rhodes University: vii + 308 pp. + 44 pp of Appendices.

Ellis, J. In press. Thomback skate or ray Raja clavata. In: Fowler, S.L., M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status o f the chondrichthy anfishes. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Ellis, J.R. and Shackley, S.E. ( 1995 ). Observations on egg laying in the thomback ray. Journal o f Fish Biology 46:903-904.

Ellis, J. and N. Dulvey. In press. Big skate Raja binoculata. In: Fowler, S.L.,M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status ofthe chondrichthy anfishes. IUCN/SSC Shark Specialist Group. KJCN, Gland, Switzerland and Cambridge, UK.

Ellis, J. and P. Walker. In press. Common skate Raja batis. In: Fowler, S.L.,M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status ofthe chondrichthy anfishes. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Fahy, E. 1991. The southeastern ray Raja spp. fishery, with observations on the growth of rays in Irish waters and their commercial grading. Ir. Fish. Invest. Ser. B, 37:18pp.

FAO Fisheries Department. 1994. World review o f highly migratory species and straddling stocks. FAO Fisheries Technical Paper, no. 337. Rome: FAO. 70pp.

FAO. 1998. International PlanofActionfortheconservationand management o f sharks. Document FFCSS/98/3. FAO Fisheries Department Consultation on the management of fishing capacity, shark fisheries and incidental catch of seabirds in longline fisheries. Food and Agriculture Organization of the United Nations, Rome, October 1998.

Fergusson, I.K. 1996. Report on the distribution & autoecology of the white shark Carcharodon carcharias in the North- Eastern Atlantic and Mediterranean Sea. Chapter 30 In: Great white sharks: Ecology & Behaviour. A.P. Klimley & D.G. Ainley, eds. Academic Press, Orlando: 321-345

Fergusson, I.K., L J.V. Compagno, and M.A. Marks, in press. White shark Carcharodon carcharias. In: Fowler, S.F., M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status o f the chondrichthyan fishes. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Fleming, E. H. and P.A. Papageorgiou. 1997. Shark Fisheries and Trade in Europe. 78pp. TRAFFIC.

Fordham, S.V. In press. Spiny dogfish Squalus acanthias. In: Fowler, S.F.,M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status ofthe chondrichthy anfishes. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Fourmanoir, P. 1961. Requins de la côte ouest de Madagascar. Mem. Inst. Sei. Madagascar (Ser. F). 4:1-81.

Fowler, S.F. 1996 a. Red fist assessments for sharks and rays. Shark News (the Newsletter of the IUCN Shark Specialist Group), 8:4-5.

Fowler, S.F. 1996 b. Status of the basking shark, Cetorhinus maximus (Gunnerus). Shark News (the Newsletter o f the IUCN Shark Specialist Group), 6:4.

Fowler, S.F. In press a. IUCN Red Fist Assessments. In: Fowler, S.F., M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status o f the chondrichthy anfishes. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Fowler, S.F. In press b. Basking shark, Cetorhinus maximus. In: Fowler, S.F.,M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status ofthe chondrichthy anfishes. IUCN/SSC Shark Specialist Group. KJCN, Gland, Switzerland and Cambridge, UK.

Fowler, S.F., M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the

11

The Implications o f Biology fo r the Conservation and Management o f Sharks

status ofthe chondrichthy an. fishes. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Fowler, S.L., M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In preparation. Sharks, rays and chimaeras: A Globed Action Plan fo r the chondrichthyan fishes. IUCN/ SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Francis, M.P. 1996. Observations on a pregnant female white shark ( Carcharodon carcharias ), with areview ofreproduction in the species. In: Great white sharks: Ecology & Behaviour. A.P. Klimley & D.G. Ainley, eds. Academic Press, Orlando.

Francis, M.P. and L.H. Griggs. 1997. Shark bycatch in New Zealand’s tuna longline fisheries (Abstract). 5th Indo-Pacific Fish Conference, Noumea, New Caledonia, 3-8 November 1997, p. 31.

Frazer,N.B. andL.M. Ehrhart. 1985. Preliminary growthmodels for green ( Chelonia mydas ) and loggerhead ( Caretta caretta ) turtles in the wild. Copeia 1985: 73-79.

Gales, R. 1993. Co-operative mechanisms for the conservation of albatross. AustralianNature Conservation Agency. Hobart, Tasmania.

Gauld, J. 1979. Reproduction and fecundity of the Scottish- Norwegian stocks of spurdogs Squalus acanthias, (L.) ICES C.M. 1979/H:54.16 pp.

Gauld, J. A. 1989. Records ofporbeagles landedin Scotland, with observations on biology, distribution and exploitation of the species. ScottisliFisheriesResearcliReportno. 45. Department of Agriculture and Fisheries for Scotland. Aberdeen.

Gilmore, R. G. 1993. Reproductive biology of lamnoid sharks. Environmental Biology o f Fishes 38,95-114.

Gilmore, R. G. D., Dodrill, J. W. and Linley, P. A. 1983. Reproduction and embryonic development of the sand tiger shark, Odontaspis taurus (Rafinesque). Fisheries Bulletin 81(2), 201-225.

Goldman, K. 1998. Demographic analyses for sand tiger sharks and dusky sharks. Part 3. In: VIMS Shark Ecology Program, J.A. Musick, J. Gelsleichter, R.D. Grubbs, and K. Goldman. Appendix SB-IV-13. NOAA/NMFS Shark Evaluation Workshop, June 1998. Panama City, FL, 3 pp.

Goldman, K. in press. Thresher shark Alopias vulpinus. In: Fowler, S.L., M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status ofthe chondrichthy anfishes. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Grant, C .J., R.L. Sandland, and A.M. Olsen. 1979. Estimation of growth, mortality, and yield per recruit of the Australian school shark, Galeorhinus galeus (Macleay), from tag recoveries. Austr: J. Mar. Freshw. Res. 30: 625-637.

Hamlett, W.C. 1997. Reproductive modes of elasmobranchs. Shark News (Newsletter ofthe IUCN Shark Specialist Group) 9:1-3.

Hanfee, F. 1997. Trade in Sharks and Shark Products in India, A preliminary survey. 50pp. TRAFFIC.

Hazin, F.H.V. 1993. Fisheries-oceanographical study on tunas, billfishes and sharks in the southwestern equatorial Atlantic

Ocean. Doctoral thesis, Graduate School ofFisheries, Tokyo University ofFisheries, 286 pp.

Heupel, M. In press. Blacktip reef shark Carcharhinus melanopterus. In: Fowler, S.L., M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status o f the chondrichthyan fishes. IUCN/ SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

HillbomR. andC.J. Walters. 1992. Quantitative Fisheries Stock Assessment. Chapman and Haii, New York. 570 pp.

H inman, K. and C. Safina. 1992. Summary and Recommendations. In: R.H. Stroud (ed.), Stemming the tide o f coastalfishhabitatloss. Marine Recreational Fisheries 14. Proceedings of a Symposium on conservation of coastal fish habitat, Baltimore, Maryland, March 1991. National Coalition for Marine Conservation, Georgia, USA.

Hitz, C .R. 1964. Observations on egg cases ofthe big skate (Raja binoculata Girard) found in Oregon coastal waters. J. Fish. Res. Bd. Canada, 21:851-854.

Hoenig, J.M., and S.H. Gruber. 1990. Life-history patterns in the elasmobranchs: implications for fisheries management. In: Elasmobranchs as living resources: advances in the biology, ecology, systematics, and the status o f fisheries. (H.L. Pratt, Jr., S.H. Gruber andT Taniuchi, eds. ),pp. 1 -16. U.S. Department of Commerce, NOAA Technical Report NMFS 90.

Hoey, J.J. R.J. Conser, and A.R. Bertolino. 1990. The western North Atlantic swordfish. In: Audubon Wildlife Report 1989/ 1990: 457-477.

Hoff, T. B., and J.A. Musick. 1990. Western North Atlantic shark-fishery management problems and informational requirements. In: Elasmobranchs as living resources: advances in the biology, ecology, systematics, and the status o f fisheries, eds H.L. Pratt, Jr., S.H. Gruber, andT. Taniuchi. U.S. Department of Commerce, NOAA Technical Report NMFS 90. pp. 455-472.

Holden, M.J. 1974. Problems in the rational exploitation of elasmobranch populations and some suggested solutions. In: Sect Fisheries Research, edited by F.R. Harden Jones. New York: John Wiley and Sons. pp. 117-137.

Holden, M.J. 1975. The fecundity of Raja clavata in British waters./. Coris. int. Explor. Mer, 36(2):110-118.

Holden, M.J. and M.R.Vince ( 1973 ). Age validation studies on the centra of Raja clavata using tetracycline. J. Coris, int. Explor Mer, 35(1):13-17.

Huntsman in press. In J.A. Musick (ed. ).ICCAT. 1996. SCRS Executive Summary. Swordfish Detailed

Report, Oct. 19 1996. Madrid, Spain.IUCN 1996. IUCN Red l is t o f Threatened Animals. IUCN

Cambridge, check full citation.Jensen, A.C. 1965. Life history ofthe spiny dogfish. Fish. Bull.

65:527-554.Jones, B.C. and G.H. Geen. 1977. Age and growth of spiny

dogfish (Squalus acanthias L. ) in the Strait o f Georgia, British Columbia. Fish. Mar: Sen: Res. Dew Tech. Rep. 669:16 pp.

Joung, S.J., Chen, C.T., Clark, E., Uchida, S. & Huang, W.Y.P.

12

The Implications o f Biology’ fo r the Conservation and Management o f Sharks

1996. The whale shark, Rhincodon typus, is a livebearer: 300 embryos foundinone ‘megamamma’ supreme.Environmental Biology’ o f Fishes, 46,219-223.

Ketchen, K. S. 1975. Age andgrowthofdogfish^/a/rw acanthias inBritish Columbia waters. Journal ofthe Fisheries Research Board Canada 32: 43-59.

Killam, K.A. and G.R. Parsons. 1989. Age and growth of the blacktip shark, C. limb atas, near Tampa Bay, Florida. Fish. Bull. US 87(4): 845-858.

Klinowska M. and J. Cooke. 1991. Dolphins, Porpoises and Whales o f the World. The IUCN Red Data Book. IUCN, Gland, Switzerland and Cambridge, UK. 429 pp.

Kotas, J.E. In press. In: Fowler, S.L., M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status ofthe chondrichthyan fishes. IUCN/ SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Krough, M. 1994. Spatial, seasonal and biological analysis of sharks caught in the New South Wales Protective Beach meshing program. Aust. J. Mar. Freshw. Res. 45:1089-1106.

Kunzlik, P.A. 1988. The basking shark. Scottish Fisheries Information Pamphlet No. 14. Department of Agriculture and Fisheries for Scotland. Aberdeen.

Last, P.R. and J.D. Stevens. 1994. Sharks and rays o f Australia. CSIRO Division ofFisheries. 513 pp.

Laursen, L. and M. Bekoff. 1978. Toxodonta africana. Mammalian Species 92:1-8.

Leet, William S., Christopher M. Dewees and Charles W. Haugen. 1992. California's Living Marine Resources and Their Utilization. California Sea Grant Extension Publication UCSGEP-92-12: 257 pp.

Lenanton, R.C.J., Heald, D.I., Platell, M., Cliff, M., and Shaw, J. 1990. Aspects o f the reproductive biology of the gummy shark, Mustelus antarcticus Günther, from waters off the south coast of Western Australia. Australian Journal o f Marine and Freshwater Research 41, 807-822.

Lessa R., C. M. Vooren & J. Lahaye. 1986. Desenvolvimento e Ciclo Sexual das femeas, migraçôes e fecundidade da Viola, Rhinoba tos horkelii (Muller & Henle, 1841 ) do Sul do Brasil. Atlantica, Rio Grande, 5-34p.

Lessa, R. and C.M. Vooren. In press. Brazilian guitarfish Rhinobatos horkelii. In: Fowler, S.L.,M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status ofthe chondrichthy anfishes. IUCN/ SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Lessa, R. P. T. 1982. Biologie et Dynamique des Populations de Rhinobatos horkelii du plateau Continental du Rio Grande do Sul. These de Doctorat. Faculté des Sciences de Brest, Université de Bretagne Occidentale, 250 pp.

Marshall, N.T. and R. Bamett (Eds). 1997. Trade Review: The Trade in Sharks and Shark Products in the Western Indian and Southeast Atlantic Oceans. 132pp. TRAFFIC.

Martin, L. and Zorzi, G.D. 1993. Status and review of the California skate fishery. NOAA Tech. Rep. NMFS 115,39-52.

Martin, L.K. andG.M. Cailliet. 1988a. Ageandgrowthofthebat ray, Myliobatis californica, off central California. Copeia 1988(3): 762-773. '

Martin, L.K. and G.M. Cailliet. 1988b. Aspects o f reproduction in the bat ray, Myliobatis californica, in central California. Copeia 1988(3): 754-761.

McFarlane, G.A. and R.J. Beamish. 1987. Validation of the dorsal spine method of age determination for spiny dogfish. In: R.C. SummerfeltandG.E. Haii, eds, The Age and Growth o f Fish. Pp. 287-300. Iowa State Univ. Press, Ames, USA.McNally,K. 1976. TheSun-FishHunt.Bhcksta.ffPvess, Belfast.

McPherson, G., N. Gribble,andB. Lane. 1998. Sharkcontrolrisk management in Queensland: a balance between acceptable levels of bather safety, public responsibility and shark catch. In: N.A. Gribble, G. McPherson and B. Lane. Shark Management and Conservation. Proceedings from the Sharks and Man workshop of the Second World Fisheries Congress, Brisbane, Australia, August 1996.

Mollet, H.F., G. Cliff, , H.L. Pratt, and J.D. Stevens. 1997. Reproductive parameters of the shortfin mako, Isurus oxyrinchus. Program and Abstracts of 77th Annual Meeting ofAmerican Society oflchthyology and Herpetology. Pp. f 214.

Morrissey, J.F. and S.H. Gruber. 1993. Home range of juvenile lemon sharks, Negaprion brevirostris. Copeia 1993(2): 425- 434.

Moulton, P. M., T. I. Walker and S. R. Saddlier 1992. Age and growth studies ofgummy ûm\yMustelus antarcticus Günther, and school shark, Galeorhinus galeus (Linnaeus), from southem-Australian waters. Australian Journal o f Marine and Freshwater Research 43,1241-1267.

Musick, J. 1995. Critically endangered large coastal sharks, a case study: the sandbar shark, Carcharhinus plumbeus (Nardo, 1827). Shark News (the Newsletter of the IUCN Shark Specialist Group), 5 (October):6-7.

Musick, J.A. 1997. Stocks at risk. Fisheries. 22(7):31-32.Musick, J.A. 1998. Endangered marine fishes: criteria and

identification of North American stocks at risk. Fisheries 23(2): 28-30.

Musick, J. In press. Sandbar shark Carcharhinus plumbeus. In: Fowler, S.L.,M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status ofthe chondrichthy anfishes. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Musick, J. A., Branstetter, S. and Colvocoresses, J. A. 1993. Trends in shark abundance from 1974 to 1991 for the Chesapeake Bight region of the U.S. Mid-Atlantic coast. In Branstetter, S. (Ed. ) Conservation Biology o f Elasmobranchs. NOAA Technical Report NMFS 115, pp. 1-18.

Musick, J.A. and J.A. Colvocoresses. 1988. Seasonal recruitment of subtropical sharks in Chesapeake Bight, US A In: W orkshop on recruitment in tropical coastal demersal communities (A. Yanez, Y Arancibia, andD. Pauly, eds. ); Campeche, Mexico, 21-25 April 1986. FAO/UNESCO, I.O.C. Workshop Rept. No. 44.

13

The Implications o f Biology fo r the Conservation and Management o f Sharks

Nakano, H. 1994. Age, reproduction and migration of blue shark in the North Pacific Ocean. Bulletin o f Na tional Research Institute o f Far Sects Fisheries, 31,141-256.

Nammack, M.F., J.A. Musick, and J.A. Colvocoresses. 1985. Life history of spiny dogfish off the Northeastern United States. Transactions o f the American Fisheries Society 114:367-376. [use Trans. Am. Fish. Soc.l]

Natanson, L.J. and G.M. Cailliet. 1986. Reproduction and development ofthe Pacific angel shark, Squatina californica, off Santa Barbara, California. Copeia 1986 (4): 987-994.

Natanson, L.J. and G.M. Cailliet. 1990. Vertebral growth zone deposition in Pacific angel sharks. Copeia 1990 (4): 1133- 1145.

Natanson, L.J., J.G. Casey, and N.E. Kohler. 1995. Age and growth estimates forthe dusky shark, Carcharhinus obscurus, in the western North Atlantic Ocean. Fish, Bull. 93:116-126.

National Marine Fisheries Service. 1995. Status o f the Fishery Resources ofFtheNortheastemUnited States for 1994. NOAA/ Dept. Of Commerce. Woods Hole, MA. 140 pp.

NOAA (National Oceanographic and Atmospheric Organization). 1996.1996 ReportoftheSharkEvaluation Workshop. NMFS, NOAA, Dept, of Commerce. June 1996. 80 pp.

NOAA (National Oceanographic and Atmospheric Organization). 1998.1998 ReportoftheSharkEvaluation Workshop. NMFS, NOAA, Dept, of Commerce. June 1998.109 pp.

NOAA (N ational O ceanographic and Atm ospheric Administration). 1998. Advisory Report on Stock Status (SAW-26 Corrigendum - spiny dogfish). NOAA, NMFS, NEFSC Woods Hole, Massachusetts.

Norman, B. In press. Whale shark Rhincodon typus. In: Fowler, S.L., M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status o f the chondrichthy an fishes. IUCN/SSC Shark SpecialistGroup. IUCN, Gland, Switzerland and Cambridge, UK.

Notarbartolo di Sciara, G. In press. Dark clouds onMediterranean elasmobranchs: the case of the endemic skates. Shark News.

Nottage, A. S. and E.J. Perkins (1983). Growth and maturation of roker, Raja clavata L. in the Solway Firth J. Fish Biol., 23:43- 48.

Nowell, K. and P. Jackson. 1996. Wild Cats: Status Survey and Conservation Action Plan. IUCN/SSC Cat Specialist Group. 406 pp.

Oliver, A. 1997. Draft discussion paper pursuant to CITES Resolution CONF. 9.17. An overview ofthe biological status of shark species. US National Marine Fisheries Service. Report prepared for the CITES Animals Committee, Silver Springs, Maryland. 53pp + appendices.

Olsen, A.M. 1954. The biology, migration, and growthrate ofthe school shark, G aleorhinus australis (M acleay)( Carcharhinidae ) in south-eastern Australian waters. Austr. J. Mar. Freshw. Res. 5,353 410.

Parker, H.W. and Stott, F.C. 1965. Age, size and vertebral calcification in the basking shark Cetorhinus maximus (Gunnerus). Zoologische Mededelingen, 40(34):, 305-319.

Parsons, G. R. 1983. Examination ofvertebral rings ofthe Atlantic sharpnose shark, Rhizoprionodon terraenovae. Northeast

Gulf Sei. 6(1): 63-66.Parsons, G.R. 1993a. Age determination and growth of the

bonnethead shark Sphyrna tiburo: a comparison of two populations. Mar. Biol. 117:23-31.

Parsons, G.R. 1993b. Geographic variation in reproduction between two populations of the bonnethead shark, Sphyrna tiburo. Environ. Biol. Fishes 38:25-35.

Parsons, G.R. 1985. Growth and age estimation of the Atlantic sharpnose shark, Rhizoprionodon terraenovae: a comparison of techniques. Copeia 1985(1): 80-85.

Paterson, R.A. 1990. Effects of long-term anti-shark measures on target and non-target species in Queensland, Australia. Biological Conservation 52:147-159.

Pauly, D. 1978. A critique of some literature on the growth, reproduction and mortality of the lamnid shark Cetorhinus maximus (Gunnerus). ICES Pelagic Fish Committee paper C.M. 1978/H:17.

Peres, M.B., and Vooren, C.M. 1991. Sexual development, reproductive cycle, and fecundity o f the school shark Galeorhinus galeus off southern Brazil. Fishery Bulletin 89: 655-667.

Phipps, M.J. 1996. Shark Fisheries and Trade in the East Asian Region. TRAFFIC International, Cambridge, UK.

Pollard, D. A., Lincoln Smith, M. P. and Smith, A. K. 1996. The biology and conservation states o f the grey nurse shark (Carcharias taunts Rafinesque 1810) inNew South Wales, Australia. Aquatic Conservation: Marine and Freshwater Ecosystems 6,1-20.

Pollard, D.A. and A.K. Smith. Inpress. sand tiger shark Carcharias taunts. In: Fowler, S.L.,M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status o f the chondrichthyan fishes. IUCN/ SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Pratt, H.L. 1979. Reproduction in the blue shark, Prionace glauca. Fishery Bulletin. 77: 445-470.

Pratt, H.L. and Casey, J.G. 1983. Age and growth of the shortfin mako, Isunts oxyrinchus, using four methods. Cari J. Fish. Aquat.Sci. 40 (11): 1944-1957.

Pratt, H.L., Jr., and J.G. Casey. 1990. Sharkreproductive strategies as a limiting factor in directed fisheries, with a review of Holden’s method of estimating growth-parameters. In: Elasmobranchs as living resources: advances in the biology, ecology, systematics, and the status o f fisheries. (H.L. Pratt, Jr., S.H. Gruber and T Taniuchi, eds.), pp. 97-109. U.S. Department of Commerce, NOAA Technical Report NMFS 90.

Randall, J.E. 1992. Review of the biology of the tiger shark (Galeocerdo cuvier). Australian Journal o f Marine and Freshwater Research, 43:21-31.

Richardson, J.I. and T.H. Richardson. 1982. An experimental population model for the loggerhead sea turtle (Caretta caretta), pp. 165-176. In: Biology and Conservation o f Sect Turtles. K.A. Bjomdal (ed.). Smithsonian Institution Press, Washington, D.C.

Ripley, W.E. 1946. The biology of the soupfin Galeorhinus

14

The Implications o f Biology’ fo r the Conservation and Management o f Sharks

zygoptenis and biochemical studies of the liver. California Fishery Bulletin 64,1-96.

Roedel, P.M. and W.E. Ripley. 1950. California sharks and rays. Fish Bull. Calif. Dep. Fish Game, 75, 88pp.

Rose, D.A. 1996. An overview ofworld trade in sharks and other cartilaginous fishes. TRAFFIC International, Cambridge, UK.

Rose, D.A. March 1998. Shark Fisheries and Trade in the Americas, Volume 1: North America. 143pp. TRAFFIC.

Ryland, J.S. and T.O. Ajayi (1984). Growth and population dynamics of three Raja species in Carmarthen Bay, British Isles./. Cons. int. Explor. Mer, 41:111-120.

Sant, G. and E. Hayes (Eds). 1996. The Oceania Region’s Harrest, Trade and Management o f Sharks and other Cartilaginous Fish: An Overview. 70pp. TRAFFIC.

Saunders, M.W. and G.A McFarlane. 1993. Age and length at maturity of the female spiny dogfish. Squalus acanthias, in the Strait of Georgia, British Columbia, Canada. Env. Biol. Fishes 38:49-57.

Seki, T., T. Taniuchi, M. Shimizu, and H. Nakano. (MS). Age, growth and reproduction of the oceanic whitetip shark from the north Pacific. National Research Institute of Far Seas Fisheries, Shimizu, Japan.

Simpfendorfer 1993. Age and growth ofthe Australian sharpnose shark Rhizoprionodon taylori from North Queensland, Australia. Environmental Biology o f Fishes. 36:233-241.

Simpfendorfer, C.A. In press. Mortality estimates and demographic analysis for the Australian sharpnose shark (Rhizoprionodon taylori) from Northern Australia. Fishery Bulletin.

Simpfendorfer, C. In press. Tiger shark, Galeocerdo cuvier In: Fowler, S.F.,M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status ofthe chondrichthy anfishes. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Simpfendorfer, C. In press. Whitespotted wedgefish or giant guitarfish Rhynchobatus djiddensis. In: Fowler, S.F., M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status o f the chondrichthyan fishes. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Simpfendorfer, C.A. and N.E. Milward. 1993. Utilisation of a tropical bay as a nursery area by sharks of the families Carcharhinidae and Sphyrnidae. Environmental Biology o f Fishes 37: 337-345.

Smale, M.J. In press. Oceanic whitetip shark Carcharhinus longimanus. In: Fowler, S.F., M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status o f the chondrichthyan fishes. IUCN/ SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Smale, M.J. In press. Whitetip reef shark Triaenodon obesus. In: Fowler, S.F.,M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status ofthe chondrichthyan fishes. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Sminkey, T.R. 1996. Demographic analyses of natural and exploitedpopulations ofthree large coastal sharks. Document SB-fiI-8 ofthe 1996 Reportofthe SharkEvaluationWorkshop. June 1996. Southeast Fisheries Science Center, Miami, FF. 5 pp.

Sminkey, T.R. and J.A. Musick, 1995. Age and growth of the sandbar shark, Carcharhinus plumbeus, before and after population depletion. Copeia 4:871-883.

Sminkey, T.R. and J.A. Musick. 1996. Demographic analysis of the sandbar shark, Carcharhinus plumbeus, in the western North Atlantic. Fisheries Bulletin 94:341-347.

Smith, K.F. Jr. 1978. Metabolism of the abyssopelagic rattail Coryphaenoides armatus measured in situ. Nature, Fondon 274: 362-364.

Smith, K.F. Jr. andN.O. Brown. 1983. Oxygen consumption of pelagic juveniles and demersal adults of the deep-sea fishSebastolobus altivelis, measured at depth. Marine Biology 76: 325-332.

Smith, S.E., D.W. Au, and C. Snow. In Press. Intrinsic rebound potentials of 26 species of Pacific sharks. Marine and Freshwater Research.

Stevens, J.D. 1976. Preliminary results of shark tagging in the north-east Atlantic, 1972-1975. Journal o f the Marine Biological Association o f the United Kingdom 56,929-937.

Stevens, J.D. 1984. Fife-history and ecology of sharks at Aldabra Atoll, Indian Ocean. Proceedings o f the Roya1 Society o f london series B 222: 79-10

Stevens, J.D. and Fyle, J.M. 1989. The biology of three hammerhead sharks (Eusphyrna blochii, Sphyrna mokarran and S. levini) from Northern Australia. Australian Journal o f Marine and Freshwater Research 40,129-146.

Stevens, J.D. In press. Porbeagle shark lam na nasus. In: Fowler, S.F., M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status o f the chondrichthy anfishes. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Stevens, J.D. In press. Shortfin mako, Isurus oxyrinchus. In: Fowler, S.F.,M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status o f the chondrichthy anfishes. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Stevens, J.D. In press. Blue shark Prionace glauca. In: Fowler,S.F., M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status o f the chondrichthy anfishes. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Stevens, J.D. Inpress. School orTope shark Galeorhinus galeus. In: Fowler, S.F., M. Camhi, A. Brautigam, G. Burgess, S. Fordham andJ. Musick. Inpress. Sharks, rays and chimaeras: the status o f the chondrichthyan fishes. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland & Cambridge, UK.

Sund, 0 . 1943. Et brugdelbarsel. Naturen, 67,285-286.Sundstroem,F. andS.H. Gruber. Inpress. I ,cmon shark Negaprion

brevirostris. In: Fowler, S.F., M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. Inpress. Sharks, rays and chimaeras: the status o f the chondrichthyan fishes. IUCN/

15

The Implications o f Biology fo r the Conservation and Management o f Sharks

SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Tanaka, S., G.M. Cailliet, andK.G. Yudin. 1990. Differences in growth of the blue shark Prionace glauca: technique or population? In: H.L. Pratt, S.H. Gruber & T. Taniuchi eds. Elasmobranchs as living resources: Advances in the Biology, Ecology, Systematics, and the Status o f the Fisheries. NOAA Technical Report NMFS 90. pp. 177-188.

Tester, A.L. 1969. Cooperative Shark Research and Control Program, Final Report, 1967-69. University of Hawaii, Honolulu, iv+47 pp., Appendix tables 1-36.

Thorson, T.B. 1982. Impact of commercial exploitation on sawfish and shark populations in Lake Nicaragua. Fisheries 7(2): 2-10.

TRAFFIC Oceania and TRAFFIC USA. August 1996. A TRAFFIC Network Report to the CITE S Animals Committee on the TRAFFIC Network Global Shark Trade Study. Unpublished report. 3pp.

Uchida, S., T oda, M., T eshima, K., & Y ano, K. 1996. Preliminary Report on near-term foetuses from a white shark caught in Kochi, Japan. In: Great white sharks: Ecology & Behaviour. A.P. Klimley & D.G. Ainley, eds. Academic Press, Orlando.

van der Eist, R.P. 1979. A proliferation of small sharks in the shore-based Natal sport fishery. Environmental Biology o f Fishes, 29: 349-362.

VanDykhuizen, G. & H.F. Mollet. 1992. Growth, age estimation and feeding o f captive sevengill sharks, Notorynchus cepedianus, at the Monterey Bay Aquarium. Aust. J. Mar. Freshw. Res. 43(1): 297-318.

Walker, P.A. and J.R.G. Hislop. 1998. Sensitive skatesorresihent rays? Spatial and temporal shifts in ray species composition in the central and north-western North Sea between 1930 and the present day. ICESJournal o f Marine Science, 55: 392-402.

Walker, T. I. 1996. Stock Assessment Report. Gummy shark1995. 33 pp. (Compiled for the Southern Shark Fishery Assessment Group). ( Australian GovemmentPrinting Service: Canberra).

Walker, T.1.1983. ‘Investigationsofthe gummy shark,Mustelus antarcticus Günther, from south-eastern Australian waters’. Report to Fishing Industry Research Committee. June 1983. In ‘Proceedings of the Shark Assessment Workshop, South EastFisheriesCommittee SharkResearch Group’. Melbourne, 7-10 March 1983. 94 pp. (Department of Primary Industry: Canberra).

Walker, T.I. 1994a. Fishery model of gummy shark for Bass Strait. In ‘Proceedings of Resource Technology ‘94 New

Opportunities Best Practice’. University o f Melbourne, Melbourne, 26-30 September 1994. (Ed. I. Bishop), pp 422- 438. (The Centre for Geographic Information Systems & Modelling: The University of Melbourne).

Walker, T.I. 1994b. Stock Assessments of the Gummy Shark, Mustelus antarcticus Günther, in Bass Strait and off South Australia. In ‘Bureau of Rural Resources Proceedings No. 14: Fishery Stock Assessment, Australian Society for Fish Biology Workshop’, Sorento, Western Australia, 24-25 August 1993. (Ed. D.A. Hancock), pp 173-187. (Bureau ofRural Resources: Canberra).

Walker, T. 1.1998. Can sharkresources be harvested sustainably? A question revisited with a review of shark fisheries. Marine and Freshwater Research 49 (in press), cite with smith

Walker, T.I. In press. Gummy shark, Mustelus antarcticus. In: Fowler, S.L., M. Camhi, A. Brautigam, G. Burgess, S. Fordham and J. Musick. In press. Sharks, rays and chimaeras: the status ofthe chondrichthyan,fishes. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, UK.

Walker,T.I., Stone,T.,Battaglene,T.,andMcLoughlin,K. 1995. Fishery assessment report: the southern shark fishery 1994. (Australian Fisheries Management Authority: Canberra).

Weber,M.L. andFordham, S.V. 1997.Managing sharkfisheries: opportunities fo r international conservation. TRAFFIC International and the Center for Marine Conservation.

Wintner, S.P. and G. Cliff 1996. Age and growth determination of the blacktip shark, Carcharhinus limbatus, from the east coast o f South Africa. Fish. Bull, U.S. 94:135-144.

World Resources 1998 USE BRYANT ET AL 1998.Yudin, K.G. andG.M. Cailliet. 1990. Age and growth ofthe gray

smoothhound, Mustelus californicus, and the brown smoothhound, M. henlei, sharks from central California. Copeia 1990:191-204.

Zeiner, S.J. and Wolf, P. 1993. Growth characteristics and estimates of age at maturity of two species of skates (Raja binoculata and Raja rhina) from Monterey Bay, California. NOAA Tech. Rep. NMFS 115, 87-99.

Zorzi, G.D., and Anderson, M.E. 1988. Records of deep-sea skates, Raja (Amblyraja ) badia Garman, 1899 m á Bathyraja abyssicola (Gilbert, 1896) in the eastemNorth Pacific, with a new key to California skates. California Fish and Game 74(2): 87-105.

16

Other Occasional Papers of the IUCN Species Survival Commission

1. S p e c i e s C o n s e r v a t i o n P r io r it ie s in t h e T r o p ic a l F o r e s t s o f S o u t h e a s t A s ia . Edited by R.A. M itte rm eier and W .R. C onstant, 1985, 58pp (O ut of print)

2. P r io r i té s e n m a t i è r e d e c o n s e r v a t i o n d e s e s p è c e s à M a d a g a s c a r . Edited by R.A. M itterm eier, L.H. Rakotovao, V. Randrianaso lo , E.J. S te rling and D. Devitre, 1987, 167pp. (O ut of print)

3. B i o lo g y a n d C o n s e r v a t i o n o f R i v e r D o lp h in s . Edited by W .F. Perrin, R.K. Brownell, Zhou Kaiya and Liu J iankang, 1989, 173pp. (O ut of print)

4. R o d e n t s . A W o r ld S u r v e y o f S p e c i e s o f C o n s e r v a t i o n C o n c e r n . Edited by W .Z. L id icker, Jr., 1989, 60pp.

5. T h e C o n s e r v a t i o n B io lo g y o f T o r to is e s . Edited by I.R. S w ing land and M.W. K lem ens, 1989, 202pp. (O ut of print)

6. B i o d iv e r s i t y in S u b - S a h a r a n A fr ic a a n d i t s I s la n d s : C o n s e r v a t i o n , M a n a g e m e n t , a n d S u s t a i n a b l e U s e . C om piled by Sim onN. S tuart and R ichard J. Adam s, w ith a con tribu tion from M artin D. Jenkins, 1991, 242pp.

7. P o la r B e a r s : P r o c e e d i n g s o f t h e T e n th W o r k in g M e e t in g o f t h e I U C N / S S C P o la r B e a r S p e c i a l i s t G r o u p , 1 9 9 1 , 107pp.

8. C o n s e r v a t i o n B i o lo g y o f L y c a e n i d a e (B u t te r f l i e s ) . Edited by T .R. New, 1993, 173pp. (O ut of print)

9. T h e C o n s e r v a t i o n B io lo g y o f M o l lu s c s : P r o c e e d i n g s o f a S y m p o s i u m h e l d a t t h e 9 th I n te r n a t io n a l M a la c o lo g ic a l C o n g r e s s , E d in b u r g h , S c o t la n d , 1 9 8 6 . Edited by A lison Kay. Includ ing a S tatus Report on M olluscan D iversity, w ritten by A lison Kay, 1995, 81pp.

10. P o la r B e a r s : P r o c e e d i n g s o f t h e E l e v e n t h W o r k in g M e e t in g o f th e I U C N / S S C P o la r B e a r S p e c i a l i s t G r o u p , J a n u a r y 2 5 - 2 8 1 9 9 3 , C o p e n h a g e n , D e n m a r k . C om piled and Edited by O yste in W iig, Erik W. Born and G era ld W. G arner, 1995, 192pp.

11. A fr ic a n E l e p h a n t D a t a b a s e 1 9 9 5 . M.Y. Said, R.N. Chunge, G.C. Craig, C.R. Thou less, R .F.W . Barnes and H.T. Dublin, 1995, 225pp.

12. A s s e s s i n g th e S u s ta in a b i l i t y o f U s e s o f W ild S p e c i e s : C a s e S t u d i e s a n d In it ia l A s s e s s m e n t P r o c e d u r e . Edited by Robert and C hristine P rescott-A lien, 1996, 135pp.

13. T é c n i c a s p a r a e l M a n e jo d e l G u a n a c o [ T e c h n i q u e s f o r t h e M a n a g e m e n t o f t h e G u a n a c o ]. Edited by S ylv ia Puig, C ha ir of the South A m erican C am elid S pec ia lis t G roup, 1995, 231 pp.

14. T o u r i s t H u n t in g in T a n z a n ia . Edited by N. Leader-W illiam s, J. A. Kayera and G. L. O verton, 1996, 138pp.

15. C o m m u n i t y - b a s e d C o n s e r v a t i o n in T a n z a n ia . Edited by N. Leader-W illiam s, J. A. Kayera and G.L. O verton, 1996, 226pp.

16. T h e L iv e B i r d T r a d e in T a n z a n ia . Edited by N. Leader-W illiam s and R.K. T ibanyenda, 1996, 129pp.

17. S t u r g e o n S t o c k s a n d C a v ia r T r a d e W o r k s h o p . P r o c e e d i n g s o f a w o r k s h o p h e l d o n 9 - 1 0 O c to b e r 1 9 9 5 B o n n , G e r m a n y b y t h e F e d e r a l M in i s tr y fo r t h e E n v ir o n m e n t , N a tu r e C o n s e r v a t i o n a n d N u c l e a r S a f e t y a n d th e F e d e r a l A g e n c y fo r N a tu r e C o n s e r v a t i o n . Edited by Vadin J. B irstein, A ndreas B auer and A strid Ka iser-P oh lm ann. 1997, v iii + 88pp.

18. M a n e jo y U s o S u s t e n t a b l e d e P e c a r i e s e n la A m a z o n i a P e r u a n a . Authors: R ichard Bodm er, R olando Aqu ino , Pablo Puertas, C esar Reyes, T u la Fang and N icole G ottdenker, 1997, iv + 102pp.

19. P r o c e e d i n g s o f th e T w e l f th W o r k in g M e e t in g o f t h e I U C N / S S C P o la r B e a r S p e c i a l i s t G r o u p , 3 - 7 F e b r u a r y 1 9 9 7 , O s lo , N o r w a y . C om piled and edited by A nd rew E. D erocher, G era ld W. G arner, N ickolas J. Lunn and O yste in W iig, 1998, c. 200pp [in press]