PROCEEDINGS OF THE FIRST MEDITERRANEAN CONFERENCE ON MARINE TURTLES

Transcription

1 PROCEEDINGS OF THE FIRST MEDITERRANEAN CONFERENCE ON MARINE TURTLES Rome, October 2001 Editors: Dimitris Margaritoulis Andreas Demetropoulos

2 Disclaimer The designations employed and the presentation of the material in this document do not imply the expression of any opinion whatsoever on the part of the organizations involved in the organization of the Conference concerning the legal status of any State, territory, city or area, or of its authorities, or concerning the delimitation of their frontiers or boundaries. The views expressed in this volume are those of the authors of each paper and do not necessarily represent the views of the above-mentioned organizations. This publication should be cited as follows: Margaritoulis, D. and A. Demetropoulos (editors) Proceedings of the First Mediterranean Conference on Marine Turtles. Barcelona Convention Bern Convention Bonn Convention (CMS). Nicosia, Cyprus. 270 pp. Copies of this volume can be freely downloaded from: ISBN

3 PREFACE During the last few years, discussions have taken place in various fora regarding the possibility of organizing a pan-mediterranean marine turtle conference that would allow the Mediterranean scientific and conservation community to express its views and knowledge on these threatened species with the final aim of improving the conservationminded approach already endorsed by wildlife conservation instruments such as the Barcelona, Bern and Bonn Conventions. At the RAC/SPA meeting for the revision of the Action Plan for the Conservation of Mediterranean Marine Turtles (Arta, October 1998) a specific proposal for the organisation of a Mediterranean conference on marine turtles was made by Douglas Hykle of the Secretariat of the Bonn Convention or CMS (Convention on Migratory Species). The RAC/SPA Director, Mr Mohamed Hentati, brought the subject to the Meeting of Experts for Priority Actions for the above mentioned Action Plan (Tunis, February 1999) which responded very favourably. Further, the proposal was adopted formally by the Fourth Meeting of the National Focal Points for SPAs in the context of the Barcelona Convention (Tunis, April 1999). Eladio Fernandez-Galiano, at the Secretariat of the Bern Convention, was also very enthusiastic on the proposal and eventually the above three supra-national Conventions (Barcelona, Bern, Bonn) proceeded in funding and organizing the First Mediterranean Conference on Marine Turtles. The venue was chosen to be in Rome with ICRAM acting as the host organization. The Organizing Committee comprised by representatives of the three conventions (Marco Barbieri from the CMS, Eladio Fernandez-Galiano from the Bern Convention, Atef Ouerghi from RAC/SPA), supplemented by Giulia Mo of ICRAM and Dimitris Margaritoulis from IUCN s Marine Turtle Specialist Group (MTSG). The Conference took place at the Jolly Hotel Leonardo da Vinci, Rome, from 24 to 28 October 2001 and gathered 173 registered participants from 18 countries. The programme was organized around four main topics, which comprised the four conference sessions: Population dynamics and genetics Identification and conservation of critical habitats Interaction with fisheries Biology, ecology, etc. In addition, three workshops were organized with the following themes: Reducing mortality at sea through education of fishermen Standardization of methodologies for monitoring nesting beaches Mitigation of tourist development impacts on nesting beaches 3

4 Key-note presentations were made at the opening of the conference and at the beginning of each thematic session. Each thematic session was followed by a round table discussion where all questions were brought after some grouping by the respective Session Chair and Rapporteur. The present volume contains all contributions made during the conference, as submitted at a specific deadline after the conference. The volume is divided in the following sections: Introductory notes, key-note presentations, oral and poster contributions (not separated). Within each section abstracts are listed in alphabetical order, by author. Round table discussions led to the drafting of the Conference Highlights, which were adopted by the Conference. These are presented at the end of the volume, before the Index of Authors. We feel privileged to have undertaken the edition of the Proceedings. Our editing has been minimal and has concentrated more on the appearance than on the content of the contributions. So, the responsibility for the content falls with the authors, whom we thank for their cooperation and patience. We also thank Michael Coyne for kindly hosting the pdf file at and Alan Rees for editorial assistance. Dimitris MARGARITOULIS and Andreas DEMETROPOULOS The Proceedings Editors 4

5 TABLE OF CONTENTS 1. ABOUT THE CONFERENCE INTRODUCTORY NOTES Barcelona Convention Secretariat THE ACTION PLAN FOR THE CONSERVATION OF THE MEDITERRANEAN MARINE TURTLES ADOPTED WITHIN THE FRAMEWORK OF THE MEDITERRANEAN ACTION PLAN Eladio Fernandez-Galiano BERN CONVENTION ACTIVITIES ON MARINE TURTLES IN THE MEDITERRANEAN UNEP/CMS Secretariat THE ROLE OF THE CONVENTION ON MIGRATORY SPECIES (CMS) IN THE CONSERVATION OF MARINE TURTLES KEY-NOTE PRESENTATIONS Josette Beer-Gabel UN REGIME JURIDIQUE POUR LES TORTUES DE MER MEDITERRANEE...17 Andreas Demetropoulos IMPACT OF TOURISM DEVELOPMENT ON MARINE TURTLE NESTING: STRATEGIES AND ACTIONS TO MINIMISE IMPACT Jean Lescure LES TORTUES MARINES: BIOLOGIE ET STATUT Dimitris Margaritoulis THE STATUS OF MARINE TURTLES IN THE MEDITERRANEAN ORAL AND POSTER CONTRIBUTIONS Francisco J. Badillo, Francisco J. Aznar, Jesuãs Tomaãs and Juan A. Raga EPIBIONT FAUNA OF CARETTA CARETTA IN THE SPANISH MEDITERRANEAN

6 Eyup Baskale and Yakup Kaska CONSERVATION AND RESEARCH ASPECTS OF HATCHERY PRACTICES Flegra Bentivegna, Mariapia Ciampa, Gianfranco Mazza, Angela Paglialonga and Andrea Travaglini LOGGERHEAD TURTLE (CARETTA CARETTA) IN TYRRHENIAN SEA: TROPHIC ROLE OF THE GULF OF NAPLES Mohamed N. Bradai et Imed Jribi ECOLOGIE DE LA NIDIFICATION DE LA CAOUANNE CARETTA CARETTA EN TUNISIE, MEDITERRANEE CENTRALE Juan A. Camin ~ as and Julio Valeiras CRITICAL AREAS FOR LOGGERHEAD AND LEATHERBACK MARINE TURTLES IN THE WESTERN MEDITERRANEAN SEA AND THE GIBRALTAR STRAIT REGION Juan A. Camin ~ as and Julio Valeiras MARINE TURTLE RESEARCH IN SPAIN AND COLLABORATIVE PROJECTS WITH THE FISHERIES SECTOR Juan A. Camin ~ as, Julio Valeiras and J.P. Del Arbol EPIBIONTIC OCCURRENCE ON LOGGERHEAD TURTLE (CARETTA CARETTA) IN THE WESTERN MEDITERRANEAN AND APPLICATIONS ON BIOGEOGRAPHY Juan A. Camin ~ as, Julio Valeiras and José M. De la Serna SPANISH SURFACE LONGLINE GEAR TYPES AND EFFECTS ON MARINE TURTLES IN THE WESTERN MEDITERRANEAN SEA Ali Fuat Canbolat BELEK: THE MOST IMPORTANT SEA TURTLE NESTING SITE ALONG THE TURKISH MEDITERRANEAN COASTLINE Ali Fuat Canbolat and Ismail Nalbantoglu PROBLEMS FACING SEA TURTLES IN THE BELEK TOURISM DEVELOPMENT AREA (TURKEY) AND RECOMMENDED STRATEGIES FOR THEIR PROTECTION Paolo Casale, Roberto Argano, Roberto Basso, Daniela Freggi and Guido Gerosa LEATHERBACK SEA TURTLES (DERMOCHELYS CORIACEA) IN ITALIAN WATERS Paolo Casale, Roberto Argano, Roberto Basso, Daniela Freggi and Guido Gerosa LOGGERHEAD SEA TURTLE (CARETTA CARETTA) RECORDS FROM ITALIAN WATERS

7 Paolo Casale, Luc Laurent and Gregorio De Metrio INCIDENTAL CAPTURE OF MARINE TURTLES IN THE NORTH ADRIATIC SEA BY ITALIAN TRAWLERS Keith Corbett and Max Kasparek STATUS UPDATE AND CONSERVATION PRIORITIES FOR THE GREEN TURTLE (CHELONIA MYDAS) IN THE MEDITERRANEAN Alessandro Di Maio, Fabio Maria Guarino, Vincenzo Caputo and Marco Affronte RELIABILITY OF THE SKELETOCHRONOLOGICAL METHOD IN CARETTA CARETTA FROM THE ADRIATIC SEA Dimitrios Dimopoulos, Thomas Arapis and Dimitris Margaritoulis CONSERVATION PERSPECTIVES OF THE MAJOR CRITICAL NESTING HABITATS OF CARETTA CARETTA IN GREECE Dimitrios Dimopoulos, Nikos Charalambides, Demetres Karavellas, Nikos Lalotis and Lily Venizelos THE ROLE OF NGOs IN PROMOTING THE ESTABLISHMENT OF THE NATIONAL MARINE PARK OF ZAKYNTHOS, GREECE Alberto Dominici, Franco Miglietta, Stefano Nannarelli, Sara Pont and Stefano Di Marco LOGGERHEAD INCIDENTAL CATCH BY LONGLINE FISHING IN SICILY SEA (LINOSA ) Paolo Fonti, Daniela Corsino, Marco Affronte and Dino Scaravelli BIOACCUMULATION OF HEAVY METALS IN NORTHERN ADRIATIC LOGGERHEADS Gianfranco Giannardi, Giampaolo Marzotto, Roberto Elia, Paola Meschini and Cecilia Mancusi REMOVAL TECHNIQUE OF FISH-HOOK FROM THE UPPER OESOPHAGUS IN CARETTA CARETTA Fiona Glen, Annette C. Broderick and Brendan J. Godley BOTH MEDITERRANEAN SPECIES NESTING SIDE BY SIDE: A DECADE OF CONSERVATION, MONITORING AND RESEARCH OF GREEN AND LOGGERHEAD TURTLES

8 Yakup Kaska COMPARISON OF SEA TURTLE POPULATIONS ON DEVELOPED AND UNDEVELOPED BEACHES OF TURKEY Yakup Kaska NEST AND SAND TEMPERATURES OF SEA TURTLES: CONSERVATION ASPECTS Arzu Kaska, Huseyin Bagci and Yakup Kaska GENETIC MATERIAL COLLECTION OF SEA TURTLES AND PCR AMPLIFICATIONS Max Kasparek PROPOSALS FOR SETTING-UP A CLEARING-HOUSE MECHANISM TO MONITOR MARINE TURTLE POPULATIONS IN THE MEDITERRANEAN Anna Kremezi-Margaritouli FISHERMEN AND TURTLES: A PORTABLE EDUCATIONAL KIT FOR SCHOOLCHILDREN Emmanuel Ladoukakis, Maria Dramountani, Dimitris Margaritoulis and Eleftherios Zouros RESULTS FROM GENETIC SCORING OF DEAD NESTLINGS OF CARETTA CARETTA FROM GREEK BEACHES Bojan Lazar and Nikola Tvrtkovicã CORROBORATION OF THE CRITICAL HABITAT HYPOTHESIS FOR THE LOGGERHEAD SEA TURTLE CARETTA CARETTA IN THE EASTERN ADRIATIC SEA Dimitris Margaritoulis and Kostas Teneketzis IDENTIFICATION OF A DEVELOPMENTAL HABITAT OF THE GREEN TURTLE IN LAKONIKOS BAY, GREECE Dimitris Margaritoulis, Chrissi-Yianna Politou and Luc Laurent ASSESSING MARINE TURTLE BYCATCH IN THE TRAWL FISHERIES OF GREECE Mohamed A. Nada THE ROLE OF NON GOVERNMENTAL ORGANISATIONS (NGOs) IN THE PROTECTION OF SEA TURTLES IN EGYPT. - SAVE THE SEA TURTLE PROJECT IN ALEXANDRIA (A CASE STUDY) Ismail Nalbantoglu SEA TURTLES, ECOTOURISM AND LOCAL PEOPLE. CASE STUDY: PATARA BEACH/TURKEY

9 Stefano Nannarelli, Franco Miglietta, Alberto Dominici, Andrea Scartazza, Giusi Nicolini and Stefano Di Marco NATURAL ABUNDANCES OF STABLE CARBON ISOTOPES AS A CLUE TO BETTER UNDERSTAND THE LIFE HISTORY OF LOGGERHEADS Ayse Oruç INTERACTION BETWEEN MARINE TURTLES AND TRAWL FISHERIES IN THE EASTERN MEDITERRANEAN, TURKEY Dimitris Panagopoulos, Emmanuella Sofouli, Kostas Teneketzis and Dimitris Margaritoulis STRANDING DATA AS AN INDICATOR OF FISHERIES INDUCED MORTALITY OF SEA TURTLES IN GREECE Giuliana Piccolo and Maria Teresa Manfredi NEW REPORTS ON PARASITES OF MARINE TURTLES STRANDED ALONG THE ITALIAN COASTS Roger Poland and Dominic Prosser EXPERIENCES WITH EUROPE S 1ST MEDITERRANEAN SEA TURTLE WEBSITE: EUROTURTLE Jasminka Radovicã and Ivana Jelenicã MARINE TURTLES IN CROATIA: LEGAL FRAMEWORK AND CONSERVATION EFFORTS Peter Richardson PARTNERSHIP FOR PROTECTION: THE UK MARINE TURTLES GROUPED SPECIES ACTION PLAN Dino Scaravelli, Marco Affronte and Francesca Costa ANALYSIS OF EPIBIONT PRESENCE ON CARETTA CARETTA FROM ADRIATIC SEA Kostas Teneketzis and Dimitris Margaritoulis THE INVOLVEMENT OF LOCAL COMMUNITIES IN SEA TURTLE CONSERVATION: THE CASE OF EVROTAS DELTA, LAKONIKOS BAY, GREECE Jesãus Tomãas, Francisco J. Aznar and Juan A. Raga THE INFLUENCE OF HUMAN ACTIVITIES UPON FEEDING OF THE LOGGERHEAD SEA TURTLE, CARETTA CARETTA, IN THE WESTERN MEDITERRANEAN: COSTS AND BENEFITS

10 Jesãus Tomãas, Francisco J. Badillo and Juan A. Raga A TWELVE-YEAR SURVEY ON STRANDINGS AND CAPTURES OF SEA TURTLES IN THE EASTERN SPANISH COAST Jesãus Tomãas, Amaia Gfimez de Segura and Juan A. Raga FIRST AERIAL SURVEYS OF LOGGERHEAD SEA TURTLES, CARETTA CARETTA, IN WESTERN MEDITERRANEAN WATERS Carola Vallini, Guido Gerosa, Gildo Gavanelli and Roberto Agostinis INTERACTION BETWEEN TRAWLS AND LOGGERHEAD TURTLES IN THE NORTHWESTERN ADRIATIC SEA Lily Venizelos SUSTAINABLE TOURISM AND SEA TURTLES: ANALYSING THE MEDITERRANEAN EXPERIENCE... FOOTSTEPS IN THE SAND Sedat V. Yerli and Filiz Demirayak THE ASSESSMENT OF SEA TURTLE NESTING ACTIVITY IN TURKEY AFTER 1994 SURVEY AS A REVIEW Valter Z v iz v a, Zdravko Marenc v ic v, Robert Turk and Lovrenc Lipej FIRST DATA ON THE LOGGERHEAD TURTLE (CARETTA CARETTA) IN SLOVENIA (NORTH ADRIATIC) CONFERENCE HIGHLIGHTS INDEX OF AUTHORS

11 ABOUT THE CONFERENCE The First Mediterranean Conference on Marine Turtles has been a joint initiative by the Secretariats of the following Conventions: - Convention for the Protection of the Mediterranean Sea against Pollution (Barcelona Convention, 1976) - Convention on the Conservation of Migratory Species of Wild Animals (Bonn Convention, 1979) - Convention on the Conservation of European Wildlife and Natural Habitats (Bern Convention, 1982) The event was organized with the support of the IUCN s Marine Turtle Specialist Group (IUCN/MTSG) and the Istituto Centrale Ricerca Applicata al Mare (ICRAM). ORGANISING COMMITTEE Marco BARBIERI (Bonn Convention) Eladio FERNANDEZ-GALIANO (Bern Convention) Dimitris MARGARITOULIS (Regional Chair of the IUCN s MTSG) Giulia MO (Istituto Centrale Ricerca Applicata al Mare) Atef OUERGHI (RAC/SPA, Barcelona Convention) PROGRAMME COMMITTEE Dimitris MARGARITOULIS (Coordinator) Flegra BENTIVEGNA M. Nejmeddine BRADAI Andreas DEMETROPOULOS Jean LESCURE Sedat YERLI The Organizing Committee would like to thank all conference participants and particularly the Programme Committee, the Invited Speakers (Josette Beer-Gabel, Thomas Dellinger, Andreas Demetropoulos, Graeme Hays, Jean Lescure, Max Kasparek, Dimitris Margaritoulis, also Nat Frazer for sending his key-note presentation to be read at the conference), the Session Chairs and Rapporteurs (Mohamed N. Bradai, Paolo Casale, Myroula Hadjichristophorou, Abdulmaula Hamza, Fiona Glen, Bojan Lazar, Giulia Mo, Jesuãs Tomaãs, Oguz Turkozan) and the Workshop Organizers (Dimitrios Dimopoulos, Guido Gerosa, Brendan Godley). Last but not least our greatest thanks to the conference s local host ICRAM and its then president Giuseppe Notarbartolo di Sciara. 11

12 concentration areas for Loggerheads. The previously described critical areas (the surrounding region of Gibraltar and the Balearic islands in a broad sense) represent for Loggerhead and Leatherback, but also for many other marine species as swordfish, bluefin tuna and species of marine mammals, two areas of interest for the conservation and management of the populations. National and international efforts in reducing incidental capture and fishing mortality should be taken into considerations more profoundly in the existing international action plans and agreements. The need to formulate an International Action Plan for the Marine Turtles as expressed by the IUCN during its Amman Congress is a management instrument that could reduce the undesirable capture and mortality of the two marine turtle species considered here. REFERENCES Aguilar R., J. Mas, and X. Pastor Impact of spanish swordfish longline fisheries on the loggerhead sea turtle Caretta caretta population in the western Mediterranean. Pages 1-6 in Proceedings of the Twelfth Annual Workshop on Sea Turtle Conservation and Biology (compilers: J.I. Richardson, T.H. Richardson). Jekyll Island, Georgia, February NOAA Technical Memorandum NMFS- SEFSC-361, Miami, USA. Brongersma L.D European Atlantic Turtles. Zoologishe Verhandelingen No 121, 318 pp. Camin ~ as J.A Incidental captures of Caretta caretta with surface long-lines in the western Mediterranean. Rapp. Comm. int. Mer Médit. 31(2): 285. Camin ~ as J.A., J.M. de la Serna, and E. Alot Loggerhead (Caretta caretta) frequency observed in the spanish surface long line fishery in the western Mediterranean Sea during Rapp. Comm. int. Mer. Médit. 33 (1992): Camin ~ as J.A The loggerhead Caretta caretta (Linnaeus, 1758) pelagic movements through the Gibraltar Strait. Rapp Comm. int. Mer. Médit. 34: Camin ~ as J.A., and J.M. de la Serna The loggerhead distribution in the western Mediterranean Sea as deduced from captures by the Spanish long line fishery. Pages in Scientia Herpetologica (editors: G.A. Llorente, A. Montori, X. Santos, M.A. Carretero). Barcelona, Spain. Camin ~ as J.A Avistamientos y varamientos de tortuga boba Caretta caretta (Linnaeus, 1758) en el Mar de Alboraãn y aãreas adyacentes durante el periodo Rev. Esp. Herp. 10: Camin ~ as J.A. 1997a. Is the leatherback (Dermochelys coriacea Vandelli, 1761), a permanent species in the Mediterranean Sea? XXV CIESM. Rapp. et Pro. Ver. 2:

13 EPIBIONTIC OCCURRENCE ON LOGGERHEAD TURTLE (CARETTA CARETTA) IN THE WESTERN MEDITERRANEAN AND APPLICATIONS ON BIOGEOGRAPHY Juan A. CAMIÑAS, Julio VALEIRAS and J.P. DEL ARBOL I. E. O., Oceanographic Centre of Malaga, E Fuengirola, Spain The loggerhead turtle, Caretta caretta, is the most frequent marine turtle in western Mediterranean Sea. This species is common in Iberian Peninsula waters from Alboran Sea to Gulf of Lyons. Turtle concentrations occur around Balearic islands in summer season (July - September). Loggerhead population has different origins: some turtles from nesting beaches of eastern Mediterranean and others from Atlantic Ocean mostly from northwestern Atlantic nesting beaches. Biological data of 238 turtles have been compiled from May 1999 to December 2000, by observers onboard Spanish drifting longliners. Samples and data on epibionts came from incidental captures in drifting longline gear targeted at swordfish and tuna, within two European projects (EU-DGXIV). Study projects are carried out for the Spanish Oceanographic Institute (IEO). Results on epibiont composition and occurrence patterns on carapace are presented. The first analyses are indicating a variety of fauna and flora species, including cirripedia (balaniformid and lepariformid), crustacea (decapoda, amphipoda, isopoda, ostracoda), plathelmints, molluscs, green and red algae. Implications of epibiont biogeography on identification of turtle population s origin are discussed. Identification of Atlantic epibiont species in the area could be a scientific tool to determine the population composition of loggerhead turtles in western Mediterranean Sea. 87

14 SPANISH SURFACE LONGLINE GEAR TYPES AND EFFECTS ON MARINE TURTLES IN THE WESTERN MEDITERRANEAN SEA Juan A. CAMIÑAS, Julio VALEIRAS and José M. DE LA SERNA Spanish Institute of Oceanography (IEO), Oceanographic Centre of Maãlaga, E Fuengirola, Spain INTRODUCTION Due to its ecology and feeding habits, marine turtle interactions occur often with several fishing gears. The western Mediterranean is an important fishing area for the Spanish drifting longline fleet targeting swordfish and tuna species. The monitoring and assessing of the incidental catches, particularly marine turtles, started in 1986 by the Oceanographic Centre of Maãlaga (Camin ~ as 1988, 1997, Camin ~ as and Valeiras 2001). The European Project co-funded by EU DG XIV Assessing marine turtle by-catch in European drifting longlines and trawl fisheries for identifying fishing regulations was carried out. Research efforts on catch address to the conservation of marine turtle population through appropriate fishing regulations. METHODS Studied area includes all the Spanish drifting longline fleet fishing area at western Mediterranean Sea. Data on fisheries incidental catch were collected on board from May 1999 to December Scientific observers worked onboard 22 longliners targeting swordfish, bluefin tuna and albacore from 5 different base ports (Cartagena, Aguilas, Garrucha, Carboneras and Motril). Data collection and survey strategies have been stratified in two strata by type of fleet and four strata by type of drifting longline gear. Research program was developed monthly along the whole fishing area. Data on 798 fishing sets and 2,127 marine turtles were collected attending the following standardised fishing parameters: 1. Detailed description of types of gear used: swordfish, bluefin tuna and albacore drifting longlines and swordfish semipelagic longline. 2. Fishing strategies, time schedule and fleet dynamics. 3. Technical characteristics of fishing sets, including geographic position, duration, depth, baits, type of setting, etc. 4. Environmental factors and meteorological conditions, including measures of surface temperatures, and fishing depth and temperature by specific sensors attached to gears. 5. Detailed data on commercial and incidental catches of marine species. 88

15 RESULTS Spanish drifting longline fleet is set up by boats from 4 to 22 m length. Fishing grounds include a large area of western Mediterranean between 36Æ and 44Æ N latitude and -02Æ W and 05Æ E longitude, from Gibraltar Strait to Gulf of Lyon. Longliners target swordfish (Xiphias gladius), bluefin tuna (Thunnus thynnus) and albacore (Thunnus alalunga). Fishing is carried out by four types of gear with differences on components (branch lines, hooks, float distances, main lines), fishing depth and strategy; drifting longline target swordfish (LLSWO), bluefin tuna (LLBFT), albacore (LLALB), and a semipelagic longline target swordfish (LLPB). The most important fishing effort is carried out at the marine area around Balearic islands and at the Ibiza Channel. The fleet is very dynamic and changes often the fishing methods as well as gear structures depending on the target species. Fishery targeting swordfish operates all around the year, however, several boats target bluefin tuna from May to July. Fishery targeting albacore takes from June to September. The type of gear used depends on season, target species, fishing yields and fishing area. The fishing gear structure is made up by a 19 to 60 km length main line, which drifts off and hangs from plastic floats. The branch lines hang vertically from the main line each few meters. Hooks are baited with several species of fish (mackerel, sardine, sablefish) and shortfin squids (Illex spp.). Semipelagic longline is used with several weights that set the branch lines at different depths. Longline for swordfish is usually set at late afternoon to remain during some night hour at sea. Retrieval starts at first hours of the morning and usually is over at daybreak. Time fishing schedules use to include day hours for bluefin tuna and albacore. 1. Incidental captures of marine turtle by gear A total of 2,127 marine turtles were incidentally caught during 798 observed fishing sets during study period. All marine turtles captured were loggerheads except two leatherbacks, one each year. During 1999, a total of 498 loggerhead turtles (Caretta caretta) and 1 leatherback turtle (Dermochelys coriacea) were captured in 291 monitored fishing sets. In 2000, a total of 1,627 loggerhead turtles and 1 leatherback turtle were captured incidentally in 507 sets. Tab. 1 presents a summary of the total directly observed captures of marine turtles during the observed period. Most of the loggerheads are hooked by eating the bait. Catch rates (number of turtles by 1,000 hooks) are showed in Tab. 1. Differences on loggerhead catch rates were detected by type of gear: LLALB (albacore gear), LLBFT (bluefin tuna gear), LLPB (semipelagic gear for swordfish) and LLSWO (surface longline for swordfish) (Tab.1). The highest capture rate corresponded to LLALB and LLBFT with values at 3.27 turtles by 1,000 hooks 89

16 (C.I. ( 4.03) in LLALB and 1.74 turtles by 1,000 hooks in the LLBFT (C.I. ( 0.99). The recently used gear LLPB (semipelagic gear for swordfish) did not captured turtles during the observation period (23 sets distributed in 1999 and 2000). Differences on catch rates by gear are related with fishing depth, fishing season and hook size. Two leatherback turtles were caught both entangled in drifting longline sets targeting swordfish. Captures occurred in August in both years. Catch rate was very low (0.001 and 0.002/1,000 hooks) (Tab. 1). Tab. 1. Loggerhead turtle observed catches and direct mortality in western Mediterranean drifting longline fisheries ( ). Most of the caught turtles were liberated hooked but alive. Delayed mortality is unknown. A total of 27 loggerhead turtles were boarded dead in 798 fishing sets (3.4% of total turtle catches). Tab. 1 presents the observed loggerhead turtle direct mortality by gear. Highest direct mortality rate was for LLBFT in 2000 (0.058 dead loggerhead turtles by unit effort). The direct mortality is related to the gear type and the hook position. LLALB and LLBFT produce higher direct mortality than LLSWO. The direct mortality in LLBFT should be associated not only to the gear structure and hook size but also with the fishing depth, that should make difficult reaching the water surface to breathe. A related aspect to direct mortality should be the total catch by set. Higher captures sink the gears affecting turtle mortality by reducing breath possibilities. 2. Annual total incidental catch estimations by gear Estimations of total loggerhead turtle incidental catch by Spanish drifting longliners at western Mediterranean are shown at Tab. 2. Observed catch rates by gear during 2000 were related to the total fishing effort exerted by the Spanish drifting longline fleet. Estimations on loggerhead incidental capture average 17,789 (C.I.: 3,503-29,562) individuals in Results indicate a larger incidental catch in LLSWO (2,260-22,786). Estimations on loggerhead direct mortality results in turtles per year. Delayed mortality at sea is unknown but it must be exist. 90

17 Tab. 2. Estimations on annual (year 2000) total incidental catch of loggerhead turtle by Spanish drifting longline fisheries in western Mediterranean. 3. Geographic and temporal distribution of catches The geographic distribution of loggerhead and leatherback overlap with drifting longline fishing grounds. Depending on fish species occurrence and several factors, fishermen operate along several areas. During 1999 and 2000, LLALB operated mainly north and east of Mallorca island; LLBFT south of Ibiza island; LLPB near the Iberian peninsula coast and LLSWO distributed throughout the western Mediterranean but mainly from the south of the Balearic islands to Gata Cape and north San Antonio Cape (Fig. 1). Geographic location of catches was heterogeneous along studied area, depending on month and type of gear. The most important catch rates have been detected from May to September. The incidental catches diminish during other months, although fishing effort exerted by longliners (mainly LLSWO) remained similar. Fig. 1. Geographic distribution of loggerhead turtle catches in drifting longlines in 1999 and

18 4. Turtle size distribution by gear Carapace measures of 676 onboard loggerheads were recorded. Carapace sizes from 17.2 to 72.3 cm Minimum Straight Carapace Length (MSCL) were measured (Tab. 3). Other 455 loggerheads were not boarded but sizes were estimated. Over 13% of estimated sizes (n=61) ranged from 70 to 100 cm MSCL. These large sizes permit to affirm that the Tab. 3. Loggerhead Minimum Straight Carapace Length (in mm) at western Mediterranean ( ). loggerhead population at the western Mediterranean is made up of juveniles, subadults and adults. Differences on turtle size caught were detected for the different gear types: gear targeting albacore is built with smaller size hooks; swordfish gear operates deeper than albacore gear, which represents a different availability of baited hooks; bluefin tuna and semipelagic swordfish gears operates deepest due to heavy components and fishing strategy. Regarding loggerhead catch selectivity by size, results showed differences between fishing gears (Fig. 2): the biggest turtles are captured with the LLBFT (mean=548 mm Fig. 2. Loggerhead sizes in western Mediterranean incidental drifting longline fishing catches ( ): Minimum Straight Carapace Length (MSCL) by type of gear. 92

19 MSCL); LLSWO capture medium size loggerheads (mean=495 mm MSCL) and LLALB capture the smallest sizes (mean=331 mm MSCL). The most important catch selectivity factors seem to be hook size, fishing depth and fishing schedule. ACKNOWLEDGEMENTS This work was partially carried out under the framework of the E.U. PROJECT DG XIV - 98/008: Assessing marine turtle by-catch in European drifting longlines and trawl fisheries for identifying fishing regulations. We are grateful to cofrad as, fishermen and collaborative people at the Spanish ports. Many thanks to our colleagues of Big Pelagics scientist team of IEO-Maãlaga and all the Spanish onboard observers working in our projects. REFERENCES Camin ~ as J.A Incidental captures of Caretta caretta L. with surface long-lines in the western Mediterranean. Rapport et Procès-Verbaux des Reunions de la Commision International pour l Exploration Scientifique de la Mer Mediterranée 31(2): 285. Camin ~ as J.A Capturas accidentales de tortuga boba Caretta caretta (Linnaeus, 1758) en el Mediterraãneo occidental en la pesquer a de palangre de superficie de pez espada (Xiphias gladius L.). International Commission for the Conservation of Atlantic Tunas. Collective Volume of Scientific Papers, vol. XLVI (4): Camin ~ as J.A., and J. Valeiras Spanish drifting longline monitoring program. Pages in Assessing Marine Turtle By-catch in European Drifting Longlines and Trawl Fisheries for Identifying Fishing Regulations. Final Report on Project EC-DG Fisheries 98/008. BioInsight, IEO, IMBC, STPS and University of Bari. Villeurbanne, France, 267 pp. 93