PROCEEDINGS OF THE INTERNATIONAL WORKSHOP. Promoting cooperation of Life-Nature beneficiaries and other projects for the protection of sea turtles

Transcription

1 PROCEEDINGS OF THE INTERNATIONAL WORKSHOP Promoting cooperation of Life-Nature beneficiaries and other projects for the protection of sea turtles ROME, 23 TH OCTOBER 2001

2 A special thanks to the LIFE Nature funding instrument for supporting the projects, the local communities for partecipating and all the volunteers for their support to the conservation of sea turtle. Editors Emilio Balletto Adriano D'Andrea Cristina Giacoma Susanna Piovano Alvise Zannetti Published by EDI.TUR s.r.l. for CTS - CENTRO TURISTICO STUDENTESCO E GIOVANILE Printed by FUTURA GRAFICA - Roma

3 Contents 1.A network for sea turtles pag. 5 2.Marine turtle conservation program in northwestern Mediterranean Sea pag. 7 3.Project LIFE ('97 - '99): conservation support project for North Atlantic Caretta caretta sea turtles pag LIFE funding: a significant tool in the hands of NGOs pag Life Nature project in Amvrakikos Bay: the sea turtle component pag Conservation of loggerhead turtle Caretta caretta in the Balearic archipelago pag Urgent measures for the conservation of Caretta caretta in the Pelagian Islands pag Evaluations on the use of transponders to mark indiviaduals in Caretta caretta pag How to exploit the potential of biometric data analysis: comparison of data files and methodologies in Caretta caretta pag Constraints and innovation in remote turtle tracking pag Final remarks pag Data sheets pag Authors pag. 57 PROCEEDINGS OF THE INTERNATIONAL WORKSHOP 3

4 A network for sea turtles The urgent Actions project for the conservation of Caretta caretta on the Pelagic Islands, promoted by the province of Agrigento and by the CTS, called for organizing a specific workshop for other Life Natura project chiefs and other groups active in preserving and studying sea turtles in the Mediterranean. This workshop and I thank you for your participation in it is aimed at sharing scientific and experimental knowledge and results of the current actions of preserving, researching, and protecting sea turtles in Italy, in the EU, in the Mediterranean and related area. Our workshop s output will also be useful for supplementing and enriching the preparation of the plan for the conservation of the turtles on the Pelagic Islands, to be carried out within the scope of our project. In my opinion, this meeting provides an important opportunity to promote cooperation between the various groups and to initiate a phase of sitting down together to evaluate the possibility of embarking on an effort to structure data collection standardization, which is to say of identifying common procedures for surveying biometric data and for marking, in order to obtain data that may comparable with one another, which is highly important for the purposes of outlining common and shared strategies for the conservation of sea turtles. This meeting will also give us a chance to share the knowledge acquired on the experimental systems for reducing accidental catches with fishing gear, and on satellite monitoring systems. In this regard, to guarantee the broadest possible spread of satellite tracking technology, and as an additional occasion for exchanging experiences, some satellite transmitters will be entrusted to those of you who are interested in applying these devices on specimens of Caretta caretta in your respective areas of intervention. This is to implement and validate the methodology for surveying the eco-ethological data on the species, as well as to facilitate access to the know-how developed with our project. This workshop will thus be a decisive passage for activating forms of partnership, for sharing operating methods and knowledge, and for spreading the experiences acquired over the course of this project. I would like to thank you once again for your participation. Before introducing the various groups, I would like to inform you that the proceedings of this workshop will be published. The Project Coordinator Stefano Di Marco PROCEEDINGS OF THE INTERNATIONAL WORKSHOP 5

5 Marine turtle conservation program in northwestern Mediterranean Sea SARA PONT GASAU Marine Animal Rescue Center (CRAM), Camí Ral 239 Premià de Mar Barcelona, Spain INTRODUCTION CRAM is a non-profit organization that works on the protection of endangered marine species as sea turtles, marine mammals as well as fanerogam s ecosystems. Since 1995 Cram has been running a Marine turtle Conservation Program that is focused on protecting and preserving Mediterranean loggerhead turtle (Caretta caretta) population. Northwestern Mediterranean Sea is an important developmental habitat (feeding and wintering) and migration route for juvenile and subadult loggerhead turtles (Caretta caretta). In this area, long-line fishing effort became very intensive during summer season and annually a large number ( ) of juveniles and subadults loggerhead turtles are accidentally caught (figg. 1, 2). The conservation priorities of our program are: 1. Protection and management of feeding areas and migratory routes. 2. Minimization the impact of fisheries, especially long lines fishing gear. 3. Develop research projects aimed at gathering information on dynamics and status population and trends. 4. Education and public awareness program for schoolchildren, local population local population, fishermen and other stakeholder. PROTECTION AND MANAGEMENT OF FEEDING AREAS AND MIGRATORY ROUTES One of the priorities from the Action Plan for the conservation of Mediterranean marine turtles are 1) the identification of feeding and wintering areas and migratory PROCEEDINGS OF THE INTERNATIONAL WORKSHOP 7

6 Figure 1 Juveniles and subadults loggerhead turtles are accidentally caught by long-line fishing CRAM photos routes and 2) the protection and management of known nesting, feeding and wintering areas. So CRAM, at regional level, is working on these issues through the different action lines of his Conservation Program. However, we think that if we want a effective and durable protection of Mediterranean sea turtle it will implies the cooperation of Mediterranean groups, so we have to promote and enhance the coordination between us (creation a network, European projects, exchange of techniques or whatever) MINIMIZATION THE IMPACT OF FISHERIES, ESPECIALLY LONG LINES FISHING GEAR: HELP THEM PROGRAM Marine Animal Rescue Center is carrying out a campaign among professional and coast fishermen, especially long line fishermen in order to minimize the impact of fisheries on marine turtle. We urge them to: 1. Release not injured marine turtles 2. Pick up on board the injured ones, inform to CRAM and bring them to the harbor. 3. Report sightings of turtles, areas with a high concentration, number of captures sizes etc. Figure 2 Juveniles and subadults loggerhead turtles are accidentally caught by long-line fishing 8 LIFE NATURE PROJECT CARETTA CARETTA

7 On the same way, we are carrying out a widespread campaign among coast population (local population, sailing clubs, NGO s and guard coast etc) in order to inform CRAM of all stranded turtles that arrive in Catalan coast ill, injured, dehydrated and/or undernourished, with carapace injures, pollution disorders etc. The Rescue Center undertakes a complete examination, assesses the severity of any lesions present and proceeds with whatever surgical or medical treatment is necessary (fig. 3). During the rehabilitation period we collect as many clinical and biological data as possible from turtles to achieve more knowledge of them (biometrics measures, hematology and biochemistry parameters etc). Between 1995 and 2002 we have recovered more than 700 injured loggerhead turtles All Mediterranean marine turtle Rescues Center should form a Mediterranean network working at Mediterranean level with standardized methodology that let us exchange information and experiences. Figure 3 The Rescue Center undertakes a complete examination, assesses the severity of any lesions present and proceeds with whatever surgical or medical treatment is necessary. CRAM photos DEVELOP RESEARCH PROJECTS AIMED AT GATHERING INFORMATION ON DYNAMICS AND STATUS POPULATION AND TRENDS Since 1996 we are developing some clinical and biological research projects focused to achieve more knowledge on: marine turtles population structure and dynamics, identification of critical habitats in our area, assess Catalan fisheries interaction, clinical management etc. On the last years CRAM, is exploring the population s structure of Caretta caretta in the feeding grounds of NW Mediterranean Sea by mitochondrial and nuclear DNA. We try to determine the origin populations Mediterranean or Atlantic - of the turtles that are accidentally captured by long-line fishery every summer in north of Spanish waters. Marine Animal Rescue Center and Biochemistry Department of Autonomous University of Barcelona (UAB) have been using molecular markers to identify loggerhead populations. On the same way, we would like to begin a satellite-tracking project in order to achieve data on space-time and distribution of juveniles and subadult loggerheads. Actuality, CRAM and the Barcelona University are working on biodegradable material and morphology alternative fishhooks and lines to reduce turtle mortality by hooks. We think that it is really necessary to do these studies in cooperation with other groups and working at Mediterranean level PROCEEDINGS OF THE INTERNATIONAL WORKSHOP 9

8 Figure 4 A public awareness program is as well developed for fishermen aimed at reducing the mortality of marine turtle incidentally caught in fishing gear promoting their participation on Help Them campaign. CRAM photos EDUCATION AND PUBLIC AWARENESS PROGRAM Since 1996 CRAM is carrying on an education program addressed to schoolchildren and local people. The education activities are carrying on in the Rescue Center by educators that shown them life cycle of marine turtles, critical habitats, impacts and whatever other information concerning marine turtles. Around people participated on CRAM educational program every year. A public awareness program is as well developed for fishermen aimed at reducing the mortality of marine turtle incidentally caught in fishing gear promoting their participation on Help Them campaign (fig. 4). During the year CRAM does to muc h meetings with them, and this year has done a sea turtle handling guidebook for fishermen to help them to know what can they do if they find a hooked or entangled loggerhead while working. We do, as well, a widespread campaign for the protection of Mediterranean marine turtles. It is focused to sensitize the public and encourage them support the conservation measures. References Cram, Sea turtle program in northwestern Mediterranean Sea. Actions lines and protocols of work. IUCN/SSC Marine Turtle Specialist Group, Research and management techniques for conservation of sea turtles. Action plan for the conservation of Mediterranean marine turtle, Regional Activity Center for Specially Protected Areas. 10 LIFE NATURE PROJECT CARETTA CARETTA

9 Project LIFE ('97 - '99): conservation support project for North Atlantic Caretta caretta sea turtles THOMAS DELLINGER University of Madeira - Department of Biology; Marine Biology and Oceanography Laboratory; Estação de Biologia Marinha do Funchal; Cais de Carvão - Promenade da Orla Marítima ; P Funchal / Madeira, Portugal THE PROJECT The Life project contract no. B4-3200/96/541 (Life96Nat/P/3019) addressed the ecology and conservation of the juvenile oceanic life stage of loggerhead sea turtles that live in the Eastern Atlantic Ocean within the 200 nm Economic Exclusive Zone of Madeira/Portugal, as well as outside this area of national jurisdiction. It exclusively centres on the oceanic or pelagic life stage. The project had a duration of 3 years ( ), prolonged till June 31st. It had the following objectives: 1) Determine the areas frequented by loggerhead turtles within the Madeira EEZ. If existing, determine area limits and times of the year where sea turtles are more frequently found. Determine how areas are used by sea turtles. Estimate the danger sea turtles are submitted to within these areas. 2) Develop continuous monitoring techniques to access the status of the sea turtle population at the Madeira EEZ. 3) Raise public awareness among local populations, and specifically among coastal fishing communities, of the dangers sea turtles face and the importance of Madeira waters as developmental habitat for all North Atlantic sea turtles. 4) Recover injured sea turtles for later release and set up husbandry facilities and methods. 5) Propose management guidelines for pelagic stage sea turtles. If preferential areas used by sea turtles could be found: 6) Propose these areas for inclusion in the Natura 2000 network for Madeira. PROCEEDINGS OF THE INTERNATIONAL WORKSHOP 11

10 Figure 1 Juvenile oceanic loggerhead sea turtle basking off Madeira Island/Portugal Copyright: Project LIFE: ('97 - '99) Conservation support project for North Atlantic Caretta caretta sea turtles The main results are presently being published. No preferential areas could be identified since juvenile oceanic turtle are constantly on the move, often outside jurisdictional boundaries. Seasonal variations of turtle abundance as well as differential migratory paths indicate seasonal migratory movements. An important overwintering area was detected off the coasts of Morocco and Mauritania. Coastal Marine Protected Areas cannot adequately protect these turtles, since they rarely approach coastlines. Fisheries interactions account for most of the mortality of sea turtles within Madeira EEZ. CONSERVATION PRIORITIES Though not being Mediterranean, the project addressed the following priorities foreseen by the Mediterranean Action Plan for sea turtles: Protection and management of known nesting, feeding, wintering areas and migration routes, by studying sea turtle behaviour within the pelagic feeding area off Madeira. Banning of exploitation and minimization of incidental catches, by quantifying incidental take by fishing method and raising public awareness on the results. Identification of feeding and wintering areas and migration routes, by detecting migratory and diving behaviour outside Madeira-EEZ. More knowledge on the biology of the species, in particular aspects to its life cycle, by focusing on the little known oceanic stage and using for the first time satellite linked dive recording instruments on oceanic loggerhead sea turtles. Figure 2 Members of the project team looking for sea turtles Copyright: Project LIFE: ('97 - '99) Conservation support project for North Atlantic Caretta caretta sea turtles 12 LIFE NATURE PROJECT CARETTA CARETTA

11 PROJECT/INSTITUTION/NETWORK The Madeira Sea Turtle Project was born in 1994, when a team of University of Madeira lead by the author captured the 1st juvenile oceanic loggerhead turtle off Funchal, Madeira. During these first years turtles were captured and marked and a collaborative work evolved on turtle genetics with the Archie Carr Centre for Turtle Research. From 1997 through 1999 the project was funded through Life Nature Project contract no. B4-3200/96/541 (Life96Nat/P/3019). Following the Life project, funding was received by the Portuguese Ministry of Science through contracts PRAXIS/P/BIA/11310/1998 and PDCTM/P/MAR/15248/1999. Both are collaborative projects between Portuguese Universities from Madeira (our team) as well as Azores, Algarve and Lisbon with some collaboration also from the University of Florida. This funding builds on the findings and data generated by the Life project. Strong collaborative links exist between our team and the team at Gran Canaria/Canary Islands/Spain. Joint applications are underway, since both areas are within the Macaronesian Oceanographic Region, share the same sea turtle species, as well as similar conservation problems. Collaboration on a larger European scale is welcome and our participation can take advantage of the unique Madeiran geographic position with loggerhead pelagic habitat. Figure 3 Entangled juvenile oceanic loggerhead sea turtle. Entanglement in persistent debris is a serious problem for pelagic sea turtles. Copyright: Project LIFE: ('97 - '99) Conservation support project for North Atlantic Caretta caretta sea turtles PROCEEDINGS OF THE INTERNATIONAL WORKSHOP 13

12 LIFE funding: a significant tool in the hands of NGOs KOSTAS TENEKETZIS ARCHELON the Sea Turtle Protection Society of Greece, Solomou 57, GR , ATHENS, Greece INTRODUCTION The 80s in Greece were the nascent period for the NGO movement. During this period NGOs predominantly delved in recording aspects of Greek nature and building their organisational structure. In the 90s NGOs moved into the field of management of natural resources. ARCHELON was established in 1983 to study and protect sea turtles in Greece, where the largest known loggerhead nesting populations in the Mediterranean are found. Concern for nature conservation in Greece was greatly prompted by the European Union's environmental policy as expressed through specific Directives on wildlife and habitats management. Until recently, the public services had no structure or know how to deal with nature management. It was inevitable that the administration would turn to the NGOs for implementing management plans, which in some cases were prepared by the latter (Irvine et al., 2000). The gradual harmonisation of national legislation with the EC Habitats Directive and the NATURA 2000 network paved the way for the institutionalisation of the management objectives. All major nesting beaches were included in the proposed NATURA 2000 network. At the same time EC funding instruments were providing the NGOs the opportunities to enhance their work. DISCUSSION The main objectives in implementing LIFE Nature projects for ARCHELON were to: assess the threats sea turtles face in the nesting areas, draft comprehensive and applicable management schemes to promote sea turtle conservation and sustainable development, 14 LIFE NATURE PROJECT CARETTA CARETTA

13 Figure 1 Sea turtle nesting beach on Crete under intense pressure due to tourism and where management policies are applied. (c) Thanos Belalidis / ARCHELON involve local communities in implementation of management plans create the conditions for its long-term presence at the nesting sites. This was achieved by securing: equipment (scientific, communication, transportation), infrastructure (information stations, offices, living quarters, etc). Factors contributing to the success of projects undertaken by ARCHELON include: centralised organisation and infrastructure (secretarial support, volunteers department, environmental education programme, Rescue Centre) the longstanding presence in nesting areas co-operation with the mass media both locally and nationally Up to now ARCHELON has undertaken LIFE Nature projects in three areas and is currently participating in a LIFE Nature project in the Bay of Amvrakikos: 1. LIFE Nature project on Crete ( ), "Recovery of Caretta caretta populations nesting on Crete". Successes: effective control of photopollution, control of illegal building, control of beach furniture, co-operation with tourist industry, drafting and implementation of Management Plan (Irvine et al., 1998). The "Life flashback" programme commended Crete project for its effectiveness. 2. LIFE Nature project in Lakonikos Bay ( ) "Implementation of management plan for Pylos Lagoon and Evrotas Delta, Natura 2000 sites, Greece", in co-operation with the Hellenic Ornithological Society. Successes: reduction in mortality at sea in collaboration with fishermen, restoration of sand dunes in co-operation with local authorities, removal of beach bars, systematic stranding recording, drafting and implementation of MP (Irvine et al., 2002) Figure 2 Sand dune restoration and protection actions at the sea turtle nesting beach of Evrotas Delta (NATURA 2000 site). (c) Kostas Teneketzis / ARCHELON PROCEEDINGS OF THE INTERNATIONAL WORKSHOP 15

14 3. LIFE Nature project at the Kyparissia Bay ( ) "Application of management plan in Southern Kyparissia Bay". It involves working with fishermen, drafting and implementation of a management plan. The project is still in progress. Figure 3 Sea turtle nesting beach of Kyparissia Bay. (c) Jan Hakanson / ARCHELON CONCLUSIONS Conservation of sea turtles and their habitats is a highly complex task, which requires the joint efforts of local, national and international agencies. Financial support from the LIFE Nature projects and exchange of expertise with other colleagues in the Mediterranean are critical issues for the success of species and habitats management. References Irvine C. W., Belalidis T., Siori I., Management policies for the conservation of the nesting habitat of Caretta caretta on the island of Crete, Greece. In: S.P. Epperly, J. Braun (compilers), Proceedings of the seventeenth annual sea turtle symposium. U.S. Dep. Commer. NOAA Tech. Memo. NMFS-SEFSC-415: Irvine C., Margaritoulis D., Arapis T., The role of a non-governmental organization in sea turtle conservation and management planning in Greece. In: H. J. Kalb, T. Wibbels (compilers), Proceedings of the nineteenth annual symposium on sea turtle biology and conservation. U.S. Dept. Commerce. NOAA Tech. Memo. NMFS-SEFSC-443: Irvine C., Teneketzis K., Margaritoulis D., Sand dune restoration behind the nesting beaches of Lakonikos Bay, Greece. In: A. Mosier, A. Folley, B. Brost (compilers), Proceedings of the twentieth annual symposium on sea turtle biology and conservation. NOAA Tech. Memo. NMFS-SEFSC-477: LIFE NATURE PROJECT CARETTA CARETTA

15 Life Nature project in Amvrakikos Bay: the sea turtle component PANAGOPOULOS DIMITRIOS ARCHELON the Sea Turtle Protection Society of Greece, Solomou 57, GR , ATHENS, Greece The presence of loggerhead turtles in Amvrakikos Bay has been documented by ARCHELON. Fishermen have been complaining that sea turtles cause damages to their fishing gear. They view sea turtles as competitors and exhibit negative attitudes. To document the impact of fisheries on sea turtles in the area, ARCHE- LON in the context of a LIFE Nature project for the management of the Bay run by a local developmental agency (ETANAM), set up a collaborative program with fishermen. The main objective of the ARCHELON project in Amvrakikos was to assess the problem of sea turtle mortality and raise awareness. Specific actions were designed including flipper tagging, satellite and radio tracking (Fig. 1), genetic analysis, collaborating with fishermen and rescuing injured turtles. Collaboration with coastal fishermen involved live interviews at 15 fishing ports. For each port 2-3 co-operative fishermen were interviewed on a monthly basis in order to collect information on interaction with sea turtles. Further, collaborative fishermen became part of a stranding network that operated in conjunction with ETANAM and local Port Authorities. Injured or weak animals were transported to the ARCHELON-Rescue Center at Glyfada, Athens. PROCEEDINGS OF THE INTERNATIONAL WORKSHOP 17

16 Figure 1 Sea turtle equipped with a satellite transmitter released in Amvrakikos Bay. (c) ALan F. Rees / ARCHELON Since the beginning of the LIFE project in 2000, 14 turtles along the Amvrakikos coastline were found dead (Fig. 2). Furthermore, 2 more injured were found and transported to the Rescue Center. 63% of the 16 specimens were intentionally killed. All of the injured and dead sea turtles were entangled in fishing gear. Furthermore the LIFE project involved raising public awareness mainly of schoolchildren. To date over 1,200 students have participated in environmental education activities carried out by ARCHELON in the area. Additionally, 20,000 educational coloring books on sea turtles were distributed through ETANAM to schools APR MAY JUN JUL AUG SEP OCT Figure 2 Seasonal distribution of stranded turtles from Amvrakikos Bay ( , n=16) We anticipate that by the end of the project, we will have through flipper, radio and satellite tracking significant information on how frequently the Bay is used by turtles and how serious the problem with the fishermen is. 18 LIFE NATURE PROJECT CARETTA CARETTA

17 Conservation of Loggerhead Turtle Caretta caretta in the Balearic archipelago (western Mediterranean) CARLOS CARRERAS, LUIS CARDONA and ALEX AGUILAR Department of Animal Biology, Faculty of Biology, Avda. Diagonal 645, Barcelona, Spain and Group de Biologia de la Conservació, Fundació Bosch i Gimpera, C/ Baldiri Reixac 4-6, Barcelona, Spain INTRODUCTION Loggerhead (Caretta caretta L., 1758) is the most abundant marine turtle in the western Mediterranean (Broderick et al., 2002), where specimens from Atlantic and eastern Mediterranean rookeries share foraging areas (Laurent et al., 1998). Reproductive failure, due to beach destruction and egg gathering, has been considered the main cause of decline for marine turtles (Lutcavage et al., 1997). However, demographic studies suggest that the loss of juveniles and adults has a more dramatic impact on marine turtle populations than that of earlier stages (eggs, hatchlings and younger juveniles) (Crouse et al., 1987). Hence, although rookery protection is needed for marine turtle conservation, it will be useless if large juveniles and adults are not successfully protected, thus stressing the relevance of developmental habitats. Large numbers of late juvenile loggerhead turtles occur all year round off the Balearic Islands (Camiñas and de la Serna, 1995; Mejías and Amengual, 2001). Although boat collision, debris ingestion, and pollution have been identified as potential threats for turtles at sea (Lutcavage et al., 1997), available information suggests that fishing is the most important one, as some declining populations recovered once fishing mortality was reduced (NMFS-SEFSC 2001). The Balearic archipelago supports a large fishing fleet (Iglesias and Martorell, 1990), reinforced throughout the warm season by longliners from south-eastern Spain (Camiñas and de la Serna, 1995). Incidental catch of loggerhead turtles have been reported from other heavily fished areas around the world (Delaugerre, 1987; Laurent, 1991; Aguilar et al., 1995; Godley et al., 1998; Nichols, 1999; Witzell, 1999) and loggerhead by-catch PROCEEDINGS OF THE INTERNATIONAL WORKSHOP 19

18 Figure 1 The Balearic archipelago is an important developmental habitat for loggerhead turtles. off the Balearic archipelago may affect negatively the stocks in the nesting beaches elsewhere. The aims of the LIFE Project 2000, NAT/E/ Protection of Posidonia grassas in SCIs of Baleares v, are: (1) identifying mortality sources for loggerheads in the Balearic archipelago, (2) assessing the contribution of the eastern Mediterranean and Atlantic rookeries to the Balearic stock, and (3) describing habitat use off the archipelago. This information will be used for developing a management plan for loggerheads in the area. MATERIAL AND METHODS INCIDENTAL CATCH A survey including a questionnaire and observers onboard fishing vessels will be conducted to assess total turtle catch off the Balearic Islands. The survey will be stratified in agreement with the information supplied by the Fisheries Office of the Balearic Islands (Direcció General de Pesca del Govern de les Illes Balears), who registers all the professional fishing vessels whose base harbour is in the archipelago. Questions about exploited fishing grounds, fishing gears, and turtle by-catch will be included. ORIGIN Samples will be collected from immature specimens occurring off the Balearic Islands (nesting beaches do not occur in the area) and from rookeries in Eastern Turkey, Cyprus, Greece (Zakinthos, Peloponesus and Figure 2 Fishing is though to be a major threat for loggerhead turtles off the Balearic archipelago. 20 LIFE NATURE PROJECT CARETTA CARETTA

19 Crete), and Libya. Samples form American beaches are not needed, as detailed analyses of mitochondrial and nuclear DNA have already been conducted. The D- loop region of mitochondrial DNA and nuclear microsatellites will be analysed. Organic pollutants will be also analysed, as they can be used as tracers. HABITAT USE Aerial surveys and satellite tracking will be used for studying turtle distribution and movements in the Balearic archipelago. Analysis of stable C and N isotopes will be used for gathering information about feeding habits. Blood samples will provide information about recent (weeks) meals, whereas carapace samples will provide information on the long run (months). References Aguilar R., Mas J., Pastor X., Impact of the Spanish swordfish long-line fisheries on the loggerhead sea turtle Caretta caretta population in the western Mediterranean. In: J.L. Richardson, J.I. and T.H. Richardson (eds.), ÅgProceedings of the 12th Annual Workshop on Sea Turtle Biology and ConservationÅh. NOAA Tech. Mem. NMFS-SEFSC-361: 1-6. Broderick A.C., Glen F., Godley B.J., Hays C., Estimating the number of green and loggerhead turtles nesting annually in the Mediterranean. Oryx, 36 (3), in press. Camiñas J.A., de la Serna J.M The Loggerhead distribution in the Western Mediterranean Sea as deduced from captures by the Spanish Long Line Fishery. In: G. Llorente, A. Montori, X. Santos and M.A. Carretero (eds), Scientia Herpetologica, pp Crouse D.T, Crowder L.B., Caswell H A stage-based population model for loggerhead sea turtles and implications for conservation. Ecology, 68 (5): Delaugerre M., Statut des Tortues marines de la Corse et de la Méditeranée. Vie Milieu, 37: Iglesias M., Martorell J.M., La pêche artisanales dans la región Baléare. Rapp. Comm. Int. Mer Médit., 32 (1): 254. Laurent L., Les tortues marines des côtes françaises méditerranéennes continentales. Faune de Provence (C.E.E.P.), 12: Laurent L., Casale P, Bradai M.N., Godely B.J., Gerosa G., Broderick A.C., Schroth W., Schierwater B., Levy A.M., Freggi D., Abd El-Mawla E.M., Hadoud D.A., Gomati H.E., Domingo M., Hadjichristophorou M., Kornaraky L., Demirayak F., Gautier Ch., Molecular resolution of marine turtle stock composition in fishery bycatch: a case study in the Mediterranean. Mol. Ecol., 7: Lutcavage M.E., Plotkin P., Witherington B., Lutz P.L., Human Impacts on Sea Turtle Survival. In: P.L. Lutz and J.A. Musick (eds.), The Biology of Sea Turtles, pp Mejías R. I., Amengual J., Libre vermell dels Vertebrats de les Balears. Govern de les Illes Balears. Conselleria de Medi Ambient. Nichols W.J., Resendiz A., Mayoral-Russeau C., Biology and conservation of loggerhead turtles (Caretta caretta) in Baja California, Mexico. In: H.J. Kalg and T. Wibbels (eds.), ÅgProceedings of the 9th Annual Symposium on Sea Turtle Biology and ConservationÅh. U.S. Dept. Commerce. NOAA. Tech. Memo. NMFS-SEFSC-443: NMFS-SEFSC (National Marine Fisheries service- SouthEast Fisheries Science Centre), Stock Assessments of loggerhead and leatherback sea turtles and assessment of the impact of the pelagic longline fishery on the loggerhead an leatherback sea turtles of the western North Atlantic. U.S. Department of Commerce NOAA Technical Memorandum NMFS-SEFSC 455, 343pp. Witzell W.N., Distribution and relative abundance of sea turtles caught incidentally by the U.S. pelagic longline flleet in the western North Atlantic Ocean, Fish. Bull., 97: PROCEEDINGS OF THE INTERNATIONAL WORKSHOP 21

20 Urgent measures for the conservation of Caretta caretta in the Pelagian Islands LIFE Project 99 NAT/IT/ Provincia Regionale di Agrigento Dipartimento Conservazione Natura - CTS Dipartimento Biologia Animale e dell Uomo - Università di Torino CNR-IATA Associazione Hydrosphera. Riserva Naturale Isola di Lampedusa CRISTINA GIACOMA Università di Torino, Dipartimento di Biologia Animale e dell Uomo, Via Accademia Albertina, Torino, Italy and MICAELA SOLINAS CTS - Centro Turistico Studentesco e Giovanile, Dipartimento Conservazione Natura, Via Andrea Vesalio Roma, Italy INTRODUCTION This is a project for the conservation of sea turtles in the Pelagian Islands, supported by the European Commission through the Life Nature Program and promoted by the Province of Agrigento and CTS. The Islands of Lampedusa and Linosa were identified as Sites of Community Importance (SCI) by the Sicily Region because they are the last sites in Italy where Caretta caretta is known to lay eggs on a regular base. This project will focus on investigating the spatial and temporal distribution of Loggerhead Turtles (Caretta caretta) in the Pelagian Islands waters, as well as the impact of fishing activities on adult and sub-adult mortality rates (Balletto et al., 2000 and 2001). On land, the project will focus on reducing human disturbance on the nesting beaches. Finally, the project will investigate the effects of granulometry, colour and physical properties of beach-sand on the reproductive success of turtles and on the sex ratio of the new-borns. 22 LIFE NATURE PROJECT CARETTA CARETTA

21 All this information together with data obtained by an innovative satellite telemetry system and by testing modified fishing devices and baits to reduce their attractiveness towards sea turtles, will be taken into consideration for the definition of an Action Plan for loggerhead conservation in the Pelagian Islands Marine Reserve which is on the way of being set up. Figure 1 Turtle Rescue Centre, Linosa A. Dominici These objectives will be pursued by: 1. Actions at the local, regional and national level to enhance awareness and develop knowledge about the reasons why protective measures for sea turtles are required. 2. The protection and conservation of nesting sites and nests by actions of cleaning, surveillance and monitoring. 3. The protection of adult and sub-adult individuals by the setting up a Rescue Centre and the development of a network of collaborative fishermen working in the area in order to intervene rapidly on animals accidentally caught. 4. To reduce loggerhead by-catches by long-line fishing in the Pelagie islands, without negative impact on swordfish (Xiphias gladius) catch size, we first surveyed the local fishing methodology, then we tested experimentally the possibility (1) to reduce bait attractiveness, (2) to reduce fishing device attractiveness and (3) to utilise acoustic deterrents. 5. The drawing up of a management plan taking into account the space-time distribution of adult and sub-adult individuals. For this purpose a new system of satellite transmission has been developed at the CNR-IATA in Florence. ACTIONS TO ENHANCE AWARENESS OF THE NEED FOR PROTECTIVE MEASURES FOR SEA TURTLES The lack of awareness and information on the necessity and reasons for the protection of sea turtles has currently a negative impact on the survival of the species. The production of informational pamphlets and their distribution on the ferries between Sicily and the Pelagian Islands, at the airport of Lampedusa and at a specially set up information desk on Lampedusa s main road, is designed to compensate this lack of information locally and to inform the large number of tourists visiting the islands every summer. Various other materials have been developed as part of the public awareness activities, including an informative book wholly devoted to sea turtles, a documentary and an Internet site. PROCEEDINGS OF THE INTERNATIONAL WORKSHOP 23

22 Figure 2 Turtle Rescue Centre, detachment of Lampedusa Foto A. Zannetti The creation of a Sea Turtle Rescue Centre (Figg. 1 e 2) just a few yards away from the port of Linosa, has enabled the setting up of an exhibit area open to the public. The exhibition and the educational activities carried out at the Centre aim at making the tourists, the local fishermen and the residents aware of the problems affecting the sea turtles in the Pelagian area, and at raising acceptance of conservation activities among the local people, thus improving the safety of the turtles. Similar activities are carried out on Lampedusa thanks to the support of the Dolphin Research Centre set up on the island by the CTS with contributions from the Regional Province of Agrigento. The Rescue Centre on Linosa, operating since June, was officially inaugurated on July 30, In addition to the exhibit and teaching area, it also houses a veterinary office and an area for the rehabilitation of animals needing treatment. THE PROTECTION OF NESTING SITES THROUGH CLEANING, SURVEILLANCE AND MONITORING For some time the beach of Pozzolana di Ponente on Linosa (Fig. 3) and the Conigli beach on Lampedusa (Fig. 4) have been the last sites in Italy where egg laying occurs more regularly. In the past eight years ( ) 14 nests have been recorded on Linosa and 9 episodes of false crawl of females on the beach. The low rate of human impact on the Linosa beach is shown by a daytime egg laying (late afternoon) which occurred in June On Lampedusa, since the setting up of the Isola dei Conigli Nature Reserve managed by Legambiente, 13 laying episodes have been recorded ( ). By actions of cleaning and surveillance of the beaches, and the monitoring of some environmental parameters (surface and depth temperature, degree of erosion and accumulation of rubble) the intention is to stabilise and/or restore the necessary ecological equilibrium required for the laying and development of the eggs. One of the main points discussed by this project regards the study of the thermal profiles of the two beaches at different depths. The temperature is, in fact, a critical factor for embryo development and, in particular, for the determination of gender. The Conigli beach, consisting of very light coloured sand, and the Pozzolana di Ponente beach, consisting of nearly black sand, represent two extremes from a thermal point of view. A previous survey conducted at the laying site of Linosa, showed that on the Pozzolana di Ponente beach the temperature of the sand may reach levels conside- 24 LIFE NATURE PROJECT CARETTA CARETTA

23 red incompatible with the vitality of the eggs. In this light, the exact knowledge of the thermal dynamics at the laying sites is highly important for all the actions aimed at the protection of hatching. Therefore, temperature detectors have been placed at 4 different depths both on the Conigli beach and the Pozzolana di Ponente beach, while a solar-powered meteo station has been placed on the Rescue Centre in Linosa. Figure 3 The monitoring system will thus allow, if Pozzolana di Ponente, Linosa. necessary, for the formulation of suitable, Foto A. Dominici well-founded strategies for repositioning the eggs and/or for shielding the nests. b) One of the main threats to the Pelagian turtle population is tourist activities in the nesting sites. The Legambiente volunteers on Lampedusa, and the Hydrosphera personnel, together with the CTS volunteers on Linosa, provide a 24 hour surveillance of the beaches to ensure that the eggs are not damaged or removed. This surveillance is guaranteed during the nesting and hatching periods, that is for about 18 weeks, day and night, between June and September. In the daytime the volunteers also provide information and enhance the awareness of the tourists there. Nocturnal surveillance is of fundamental importance for the sighting of females laying, in order to undertake all the operations of tagging and measuring of biometric data and, above all, to identify and protect the nests. It is also necessary to limit human interference, especially at night. Therefore, an infrared remote monitoring system able to register the presence of turtles has been placed on the Pozzolana di Ponente beach in Linosa, as a support to surveillance activities performed by the project s staff. Unfortunately, the particular geo-morphological features of the Conigli beach didn t allow the use of this system in Lampedusa. THE PROTECTION OF ADULT AND SUB-ADULT INDIVIDUALS The turtles caught accidentally are measured, given a health check-up, freed from hooks, tagged and released at the Rescue Centre on Linosa. The cure of injured animals and the operation of tagging and measurement of biometric data are conducted under the supervision of a veterinarian for the entire opening period of the Centre, from May to October. The setting up and operation of a veterinary office is of particular importance considering the large number of individuals accidentally caught every year, especially during the summer: 158 cases were documented on Linosa last summer and 112 this year (Lampedusa and Linosa), but the number is definitely higher since not all the fishermen collaborate PROCEEDINGS OF THE INTERNATIONAL WORKSHOP 25

24 Figure 4 Conigli beach, Lampedusa. Foto S. Gismondi by reporting the catches and/or bringing the animals to the project s staff and volunteers working on the islands. The Centre is equipped with X-ray equipment, an operating table, equipment for microscopic analysis and 8 closed-circuit tanks for the rehabilitation of the animals. The turtles rescued by fishing boats are brought to the veterinarian and X-rayed to verify the presence and position of hooks. Thus the veterinarian can be more effective during the surgery necessary to remove the hook (Fig. 5). The Centre also has an SOS sea turtles service to receive messages from tourist crafts and fishermen about the sighting and/or catching of turtles. The objective of reducing threats on adults and subadults have also been pursued by starting investigations aimed at suggesting changes to be implemented onto fishing gear (longlines, bait) in order to selectively reduce their attractiveness for turtles. In order to try and reduce captures of turtles, but selectively not of swordfish (Xiphias gladius), we investigated the possibility (1) to reduce bait attractiveness, (2) to decrease the overall attractiveness of the fishing gear and (3) to utilise acoustic deterrents (Giacoma et al., 2001; Piovano et al., 2001). Experiments have been carried out on turtles lodged in the tanks of the Cattolica Aquarium (Fig. 6) and in the Linosa Rescue Centre. We found that olfactory cues are involved in prey recognition mechanisms and colour attractiveness depends on individual and partially on age. As concerns buoys, we showed that long-line buoys do not attract turtles, irrespective of having or lacking a signalling light. Concerning acoustic deterrents, we found that sounds having frequencies between 0 and 500 Hz may elicit turtle avoidance. The experimental protocol deriving from these results will be tested in the open seas thanks to the co-operation of local fishermen. Figure 5 The turtle rescued by fishing boats are brought to the veterinarian and X-rayed to verify the presence and position of hook. Foto A. Zannetti 26 LIFE NATURE PROJECT CARETTA CARETTA

25 Figure 6 Experiments at the Delphynursery of Fondazione Cetacea in Cattolica (Italy). Foto S. Piovano THE DRAWING UP OF A MANAGEMENT PLAN TAKING INTO ACCOUNT THE SPACE-TIME DISTRIBUTION OF ADULT AND SUB-ADULT INDIVIDUALS Sound planning of conservation measures requires familiarity with space-time distribution of loggerhead turtles in the waters around the islands of Linosa and Lampedusa. For this purpose, a questionnaire has been devised for use in interviewing the fishermen in order to collect all the information available. Initial analysis shows that the local sailors are quite familiar with sea turtles, that in the past sightings and catches were more frequent and that, in any case, catches occur more frequently in summer in the stretch of sea between Lampedusa and Linosa, and in shallow waters rich in nutrients. Deep water catches are more evenly distributed throughout the year. For purposes of a correct formulation of a management plan, a new satellite transmitter developed by the CNR-IATA will be applied to 30 turtles. The satellite network ensures that data can be transmitted via satellite (from a remote terminal to the Internet network) at a very low cost, with global coverage. In particular, the model of transmitter used offers the possibility of automatically obtaining data on the position of the remote terminal, using GPS (Global Positioning System). The transmitters enable researchers to track via satellite the movements of turtles for several months, thus allowing to identify the use of different areas during the inter-nesting periods. The data collected will be integrated as an informative layer with a map of the oceanographic features of the Mediterranean Sea by mean of a Geographical Informative System (GIS). The adoption of the sea turtles management Plan eventually developed, will be promoted within the drawing up of the broader Marine Reserve Plan. PROCEEDINGS OF THE INTERNATIONAL WORKSHOP 27

26 References Balletto E., Barone B., Cecconello M., D andrea A., Dell Anna L., Di Marco S., Dominici A., Giacoma C., Mari F., Miglietta F., Nicolini G., Piovano S., Pozzi L., Solinas M., Azioni urgenti di conservazione di Caretta caretta nelle isole Pelagie. In Atti 3 Congresso nazionale della Societas Herpetologica Italica (Pavia, 2000), Pianura, 13: Balletto E., Barone B., Cecconello M., D andrea A., Dell Anna L., Di Marco S., Dominici A., Giacoma C., Mari F., Miglietta F., Nicolini G., Piovano S., Pozzi L., Solinas M., Azioni urgenti di conservazione di Caretta caretta nelle isole Pelagie: il Progetto LIFE italiano. Abstracts First Italian Meeting on Sea Turtle Biology and Conservation (Policoro, 2000): 5. Giacoma C., Balletto E., Barone B., D andrea A., Dell Anna L., Di Marco S., Dominici A., Mari F., Miglietta F., Nannarelli S., Nicolini G., Piovano S., Solinas M., Azioni urgenti di conservazione di Caretta caretta nelle isole Pelagie: riduzione delle catture accidentali e dei loro effetti. Riassunti 62 Congresso Nazionale Unione Zoologica Italiana (Sanremo, 2001): 23. Piovano S., Affronte M., Balletto E., Barone B., Dell Anna L., Di Marco S., Dominici A., Gamba M., Giacoma C., Mari F., Miglietta F., Nannarelli S., Nicolini G., Solinas M., Valutazione e riduzione degli effetti di catture accidentali di Caretta caretta nelle Isole Pelagie. Riassunti 5 Convegno Nazionale sui Cetacei e sulle Tartarughe Marine (Monte Argentario, 2001), CSC online publications n LIFE NATURE PROJECT CARETTA CARETTA

27 Evaluations on the use of transponders to mark indiviaduals in Caretta caretta FRANCO MARI CTS - Centro Turistico Studentesco e Giovanile, Dipartimento Conservazione Natura, Via Andrea Vesalio Roma, Italy INTRODUCTION For quite some time now, to estimate certain parameters of a given population, such as size, movements, habitat use, mortality rates, and so on, many analysis techniques based on the capture-recapture method have been developed (e.g. Seber, 1973); an essential element common to all these techniques is that a significant number of subjects be individually recognizable. Only certain species, such as zebras, tigers, or spotted cats, have phenotypical features capable of making the various individuals recognizable one at a time. In other cases, a variety of systems has been perfected, such as tattooing, mutilation, decolorating of fur or plumage, application of coloured markings, and so on, some of which also make remote recognition of the subjects possible (e.g. Lovari, 1980). In my opinion, regardless of the species on which it is used, an ideal marking system should satisfy 10 criteria: 1. easily tolerated and not harmful to the animal s health and integrity; 2. no influence on the subject s behaviour and sociality; 3. safe for operators; 4. safe and easy to apply 5. inalterable and legible for a period at least equal to the species maximum life expectancy 6. useable at any stage of the subject s lifespan; 7. possibility of creating a sufficient number of combinations; 8. easy remote identification; 9. easy to obtain; 10. affordable. PROCEEDINGS OF THE INTERNATIONAL WORKSHOP 29

28 Figure 1 Iconel metal tag used at the Turtle Rescue Center of Linosa NATURAL MARKING As regards sea turtles in general and Caretta caretta in particular, we may say that there are no phenotypical features making it easy to discern the various individuals; a number of marking systems are thus used. Actually, some researchers maintain that in Chelonia mydas, a characterization would be possible based on the morphology and colouring of the scales on the lateral areas of the head, held to remain constant throughout growth. On this basis, Bennet and Keuper-Bennet (2001) developed a computerized photographic archive (photographs solely of the left profile of the head) in a database making it possible to search the various subjects rapidly. A trial on Caretta caretta is being performed by Centro Studi Cetacei in collaboration with our group. Although this technique has shown its validity, it has clear operative limits, also given the great movements that the subjects make during their biological cycle. EAR TAGS The type of marking most used in sea turtle studies is that based on placing ear tags on the front flippers and at times on the back ones or on the carapace. These tags, which are used on cattle, are made of a metal alloy or coloured plastic, and bear an identification code and the address of the research centre. Although this system broadly overlaps with the ideal marking system described above, it deviates chiefly in two points, which are essential to research on this species. The greatest problem appearing to emerge among researchers with this technique is that effectiveness cannot be exactly known, since there is no reliable estimate of the percentage of loss of these tags. It follows that the related data and analyses are unreliable. As a secondary consideration, the tags cannot be used on newborns. I would also like to stress an additional problem linked to the use of the plastic tags caused by the action of direct sunlight, which could occur due to turtles basking behaviour. In a specific study we conducted on the reliability of the use of these tags in the Abruzzo chamois (Rupicapra pyrenaica ornata), a field test showed that after about five months of exposure to sunlight, the colours turned green became blue and yellow became white thereby making four of the six available colours indistinguishable in field conditions (Mari et al., in prep.). PASSIVE INTEGRATE TRANSPONDER A recently introduced system is the P.I.T. Passive Integrate Transponder consisting of a small (2x11 mm) capsule made of a bio-compatible material, housing an antenna, an electronic circuit, and a microchip with an alphanumerical identifica- 30 LIFE NATURE PROJECT CARETTA CARETTA

29 tion code. The entire unit is inserted into a syringe applicator for subcutaneous injection in a sterile envelope; the implant area chosen by some groups for the turtle is the dorsal portion of the neck. At rest, the transponder is completely passive, thus requiring no energy and resulting in a manufacturer-estimated lifespan of about 20 years. Readings are made using a portable reader equipped with an antenna which, by emitting a particular frequency, makes it possible to activate the transponder s electronic circuit, thereby causing the microchip s alphanumerical code to be transmitted at a very low frequency harmful neither to the animal nor to the surrounding environment. The same antenna can also read this identification code from up to a maximum distance indicated for some models of 70 cm. The process of excitation, emission, and code reading takes just a few seconds. Currently, new readers can determine the codes of all the transponders and not just those of their own manufacturer. As regards its validity for marking Caretta caretta and other sea turtles, as mentioned above the PIT has only been in use since recently and thus, for this species, as in the wild species more generally, meaningful long-term data and specific studies are lacking. To get an idea of this system s behaviour in critical conditions, I would like to report a brief outline of the data emerging from a specific study performed from September 1990 to August 1997 on the fauna at Parco Nazionale d Abruzzo, using two transponder models (Destron Idi and Datamars/Bayer) (Mari et al, in press). The test was conducted on animals captured in the wild and on those maintained in captivity, belonging to 8 species (n=105: 58 Abruzzo chamois Rupicapra pyrenaica ornata, 16 bears, of which 13 from the Marsica area Ursus arctos marsicanus and 3 brown Ursus arctos, 12 wolves Canis lupus, 7 deer Cervus elaphus, 6 roebucks Capreolus capreolus, 5 lynxes Lynx lynx and 1 wild cat Felis silvestris), checking the operation of the system before and after implantation (n=212), and during the recapture of 54 subjects (n=228) for a maximum of 6.2 years after the implant. No subject showed signs of inflammation to the tissues or migration of the two transponder types, even during subsequent checks and the autopsies of those animals found dead, and the code was always readable. Furthermore, contrary to other findings (Fargestone and Johns, 1987; AAVV, 1988; Cannas, 1991), we never found migrations of the P.I.T from the point of implantation. These findings show that the P.I.T. gathers together most of the features of the ideal system described above, with the strength of being able to act over a longer period of time capable of covering most of this species estimated lifespan; these systems are also quite affordable (a transponder costs about 4.5 and a reader capable of reading and archiving costs about 350). On the other hand, it is not externally visible, which could involve the loss of important data if the animal were to be in contact with persons not belonging to a research group, such as fishermen. PROCEEDINGS OF THE INTERNATIONAL WORKSHOP 31

30 Assuming that the checks on the use of this system are successful, by associating the transponder to the marking with metal tags on the flippers, which can be read remotely, it will be possible to obtain a safe system for individual recognition over the long term. In this way, not only can the animal be identified remotely, but in the event of loss or deterioration of the marking, the transponder will make it possible to safely identify the recaptured animal and give it a new mark, thereby preventing the loss of precious data. Given that a P.I.T. is currently capable of storing and returning a simple alphanumerical code, the information that may be obtained from an animal with this system are not unlike those provided by a mark; thus, to have information on its past, it is necessary to contact whoever marked it or access the common data bank, if available. However, a new-generation P.I.T. has already been developed and is in advanced phase of trialling, capable of storing data other than the identification code, containing an option in which it will be possible to implement the stored data. Once this system is spread, each turtle will carry with it a copy of its own history, thereby considerably easing the work of the researcher. For now, only the current dimensions of this system (12 x 6 x 3 mm) are known. Greater difficulties are encountered in the individual recognition of newborns because of their size, as they are too small for the current transponders. All the groups actively operating in recovering and marking sea turtles must also be coordinated so as to adopt a single P.I.T system, since compatibility problems often arise between readers manufactured by different firms. References AAVV, Unpublished in-house DataMars report. 14 pp BENNET P. and U. KEUPER-BENNET, The use of subjective patterns in a green turtle profiles to find matches in an image database. Poster presented to the 21st Annual Symposium on Sea Turtle Biology and Conservation. Philadelphia February CANNAS E.A., Un sistema d'identificazione elettronico nell'anagrafe canina della Sardegna. Report by Ist. Zoopr. della Sardegna. FARGESTONE K.A. and B.E. JOHNS Transponders as permanent identification markers for domestic ferrets, black-footed ferrets, and other wildlife. J. Wildl. Manage. 51(2) : LOVARI S., Etologia di campagna. P. Boringhieri Ed., Turin. 266pp. MARI F., L. GENTILE, M. LOCATI, Utilizzo del trasponder come marcatura permanente per la fauna selvatica. Atti del II Convegno Nazionale Ecopatologia della Fauna Selvatica Bormio Ottobre 1998, in press. MARI F., L. GENTILE and E. BONAFEDE, Evaluation of plastic ear-tags for individual marking of Abruzzo chamois. In prep. SEBER, G.A.F., The Estimation of Animal Abundance and Related Parameters. Griffin, London. 32 LIFE NATURE PROJECT CARETTA CARETTA

31 How to exploit the potential of biometric data analysis: comparison of data files and methodologies in Caretta caretta ALBERTO DOMINICI, STEFANO NANNARELLI Associazione Hydrosphera, Via Oslavia Roma, Italy CRISTINA GIACOMA, SUSANNA PIOVANO Università di Torino, Dipartimento di Biologia Animale e dell Uomo FRANCO MIGLIETTA IATA-CNR, Piazzale delle Cascine, Firenze Italy SARA PONT GASAU Marine Animal Rescue Center (CRAM), Camí Ral 239 Premià de Mar Barcelona, Spain INTRODUCTION The Action plan for the conservation of Mediterranean marines turtles (RAC/SPA 2000) recognises that many important aspects of the status, biology and behaviour of marine turtles are too poorly understood to plan an effective management strategy for their conservation in the Mediterranean. The action plan identifies the improvement of our current knowledge of the population status, structure and dynamics as a priority for research and monitoring schemes. For researchers and conservationists, one of the commonest activities consists in measuring turtles. Yet, lack of standardisation and of communication among groups does not normally permit the full exploitation of the available data. Measurements can be utilised to determine the effects of size on reproductive output, the frequency of size classes, as well as to monitor growth rates and secular trends in size. Size frequency distributions are an important parameter of population structure and are often used to estimate survival probabilities (Balletto & Giacoma, 1993). Trends in average size and growth rates can indicate changes in habitat quality, contaminant effects on physiological status, or increased impact of professional fisheries. As we will see, an example of the potential of turtles mean-size analysis is offered by data taken on turtles by-captured by fishermen in the Pelagie Islands area (South Sicily) over the past 9 years. A marked decrease in size has clearly occurred over time. This trend may be a consequence of habitat deterioration, or of the PROCEEDINGS OF THE INTERNATIONAL WORKSHOP 33

32 Figure 1 Regression of Curved Carapace Length against Linear Carapace Length. increased impact of human activities, perhaps of fishing efforts. Our comparison with data obtained in Spain by CRAM demonstrates that this phenomenon may be of general relevance for the whole Mediterranean basin. In order to obtain comparable, precise and accurate measurements from the various research teams operating in the field, however, an important issue consists in finding an effective standardisation system for measuring procedures. We will offer, therefore, some suggestions for general discussion. SIZE AS A MONITORING TOOL The activity of our two Sea Turtle Rescue Centres (Hydrosphera, which operates on Linosa (I) and CRAM, which operates by Barcelona (E)) started concurrently in the mid 90s. Hydrosphera operates in the Pelagie Islands, in the Sea of Sicily, whereas CRAM has been active in the North-western section of the Mediterranean. Both Centres have been rescuing marine turtles accidentally caught by local fishermen and have developed distinct measuring and tagging programs for rehabilitated specimens. RESULTS Lacking any common measurements protocol, length data collected at the two Centres were Curved Carapace Length CCL, on Linosa, and Straight Carapace Length SCL, at Barcelona. This imposed a data conversion, which was based on the somatic growth model shown in Fig.1 (Bjorndal et al., 2000), before any comparison could be made 34 LIFE NATURE PROJECT CARETTA CARETTA

33 The graphs that are shown in this paper (Figs 2-4) illustrate some of those comparisons and highlight a specific trend towards a decrease in the mean size of the Loggerhead turtles bycatch. Such a trend is clearly detectable in all measurements collected both at Linosa and Barcelona. More exactly, Figure 2 shows a shift of the median, calculated for both sites, toward lower values, during three main periods ( , 2000 and 2001). The third graph (Fig. 3) shows a clear-cut decrease in the abundance of the bycatch fraction of size greater than 40 cm SCL. Fig. 4 shows a regression between time (expressed in days since the beginning of the activity of the two centres) and the size of all the individuals measured and tagged at both rescue centres. DISCUSSION Overall, the message is clear: the data collected at those two distant sites show a trend towards a decrease in size. In particular, the frequency distribution clarifies that the trend is not associated to any substantial change in the population structure, but rather to an increase in the number of "small" and a decrease in the number of "large" animals in the bycatch. Data shown in Fig. 3 provide a clear impression that such a decreasing-size trend is very much consistent between the two stations, while the last figure (Fig. 4) provides a quantitative evaluation of the magnitude of the decrease, which was calculated by regression and demonstrated to be in the order of -1 to -2 cm SCL per year. Figure 2 Carapace Length frequency distribution of turtles sampled by Hydrosphera (green bars) and by CRAM (yellow-red bars) during the three periods. % of individuals SCL size classes (cm) PROCEEDINGS OF THE INTERNATIONAL WORKSHOP 35

34 Figure 3 Percentage of turtles with carapace longer than 40 cm sampled by Hydrosphera (green bars) and by CRAM (yellow-red bars) during the three periods. Year 2000 = Median Linosa = 42.3 % of individuals Barcelona = 43.7 SCL size classes (cm) The ecological interpretation of these data is unfortunately not straightforward enough. Bjorndal s et al. (2000) analysis of fish stock size-changes clarified very well that when a population is impacted by a major disturbance, which eliminates individuals exceeding a given mean body size, the obvious consequence is that the mean body size of the population tends to decrease. This concept suggest that in the Mediterranean Sea, marine turtles may be also severely impacted by fishing activities, which tend to eliminate individuals exceeding a given minimun body size. Such an impact is apparently effective across a wide latitudinal range, suggesting that a strong fishing effort is undergoing across the entire Mediterranean basin. On the other hand, an increase in recruitment, consequential to a substantial increase in the number of marine turtle hatchlings, would also cause, at least in the short-term, a decrease in the mean body size of the population. This hypothesis cannot be ruled out to explain the observations made at the two Rescue Centres, since the substantial decrease in predators (namely large pelagic fishes) that has been observed in the Mediterranean over the years (Margaritoulis, 1988; Stout, 1996) might have increased the chance of survival of the Loggerhead turtle hatchlings in the region. A third hypothesis that can perhaps explain these results is a decrease in the growth rate caused by a decrease of food quantity and/or quality, or by the possibly negative effects of water contaminants. The parallel activity of the two Rescue Centres is providing important and intriguing information on the marine turtles in two areas of the South and Northwestern Mediterranean. The level of interactions between those two populations is not yet well understood, even though the recent finding in the Spanish waters 36 LIFE NATURE PROJECT CARETTA CARETTA

35 Figure 4 Regression of Curved Carapace Length of turtles sampled by Hydrosphera and CRAM over time. % of individuals SCL size classes (cm) (Tomas et al., 2001) of a Loggerhead turtle that was tagged at Linosa suggests that some interchange between those two populations actually exists. Continuation of the activities at both Centres is likely to provide more information in the coming years and thus outline the importance of those centres not only for species protection, but also as a resource for obtaining new data, which may potentially shed light on some ecological phenomena and processes that are still poorly understood. COMPARISON OF METHODOLOGIES TO COLLECT BIOMETRICAL DATA: POSSIBILITY OF ADOPTING A SINGLE METHOD FOR DATA COLLECTION As we have shown in the previous example, some indications on Loggerhead turtles status in the Mediterranean region can be obtained by comparing morphometric data collected at Turtle Rescue Centres. Frazier (1998) and Bolten (1999) addressed a number of relevant points concerning how to measure sea turtles appropriately. In order to obtain reliable measures, it is necessary to tackle three principal issues: i) which morphometric measurements should be taken, ii) which instruments ensure the highest precision and iv) which level of training is needed for surveyors, depending on the parameters and the instruments. They highlighted that the choice of method and equipment is a consequence of the levels of accuracy and precision necessary to reach the objectives of each research. Accuracy and precision do not necessarily coincide: accuracy is the closeness of a measure to the real value, while precision is the ability to read very similar values every time, i.e. the closeness to each other of repeated measurements (Fig. 5). Unless there is bias in a mea- PROCEEDINGS OF THE INTERNATIONAL WORKSHOP 37

36 suring system (instrumental or personal bias), precision will lead to accuracy and therefore precision is generally the most important practical achievement to reach. To enhance comparability of measurements taken by different teams, we analysed the degree of comparability of 11 morphometric measurements (Fig. 6) by estimating repeatability of skilled- versus unskilled-surveyors, as well as callipers (straight-line measurements) versus flexible-tape measurements (curve-line measurements). MATERIALS AND METHODS We compared data collected by 3 skilled and 7 unskilled surveyors taking 11 morphometric measurements (Fig. 7). Each surveyor took the same measurement on two non consecutive times and with each type of instrument. Every measurement was taken, in fact, with each of two instruments: high quality callipers for straightline measurements (a Mitutoyo mod digital caliper and a GPM mod.101 anthropometer) and flexible plastic-tape measures (for curved measurements). Estimating the relevance of the instrument and the surveyor s training for the precision of measurements requires that repeatability is considered. To estimate the measurements repeatability, we calculated the coefficients of variation CV of the values of the first and of the second measurements obtained by all surveyors with the same instrument. The CV allows us to compare the variability of samples, irrespectively of the unit of measure and of the sample size. Figure 5 Precise measurements are repeatable and therefore comparable but not necessarily accurate. Personal or instrument bias can cause a repeatable shift in the data collected. RESULTS Mean percent CV of carapace measurements (Tab. 1) conducted by skilled and unskilled surveyors highlighted that the error made by both groups is low and comparable, and that for skilled surveyors straight line measures are more repeatable that curved measures. As a consequence we concur with Bjorndal & Bolten (1989) in recommending to measure the minimum straight-line carapace length, which generated good results from both skilled and unskilled surveyor.we have also estimated the repeatability of flippers measurements, even if they are not taken at many centres (Tab. 2). The error made is always low, but the error of the skilled group is half that of the unskilled. Once again, measures taken by callipers are more repeatable than those taken with flexible tape. Head measurements are also not frequently taken. Results highlighted that the only way to measure the width is with callipers, because 38 LIFE NATURE PROJECT CARETTA CARETTA

37 CV skilled surveyors (6 measures) CV unskilled surveyors (14measures) S C S 1,26 11,85 1,32 2,83 18,11 2,46 HEAD max width max lenght height C ,66 S C 6,48 7,71 5,88 11,48 TAB 1 Mean % CV of carapace measurements, S=stright and C=cueved measurements CV skilled surveyors (6 measures) CV unskilled surveyors (6 measures) max lenght min lenght max width S 0,27 0,73 C 0,45 0,55 CARAPACE S 0,62 0,33 C 1,16 0,50 S 0,62 0,63 C 0,77 0,71 TAB 2 Mean % CV of flipper measurements, S=stright and C=cueved measurements LEFT FLIPPER RIGHT FLIPPER angle-end angle-end CV skilled surveyors (6 measures) CV unskilled surveyors (14 measures) S 0,92 1,96 C 1,44 2,83 S 1,20 2,80 C 1,54 2,66 TAB 3 Mean % CV of head measurements, S=stright and C=cueved measurements CV skilled surveyors (6 measures) CV unskilled surveyors (14 measures) S 1,74 2,26 C 2,06 TAIL tot lenght post-cloaca carapace-tip of the tail S 8,59 C S C 4,02 25,78 0,00 2,84 14,28 11,77 24,49 32,88 TAB 4 Mean % CV of tail measurements, S=stright and C=cueved measurements PROCEEDINGS OF THE INTERNATIONAL WORKSHOP 39

38 Figure 6 Selected measurements. In this picture you can see all the measures we took during our test. Measures were taken with callipers (straight-line measurements) and with flexible-tape (curved measurements). Head width (HW) and head hight (HH) are measured at the widest point. Head length (HL) is measured from the tip of the nose to the end of parietal shields. Maximum carapace length (CLmax) is measured from the anterior edge of the carapace to the posterior tip of sopracaudals (anterior and posterior locations must be on the same side of the carapace). Minimum carapace length (CLmin) is measured from the anterior point at midline (nuchal scute) to the posterior notch at midline between the sopracaudals. Carapace width (CW) is measured at the widest point. Total tail length (TTL) is measured from the midline of the posterior margin of the plastron to the end of the tail. Post-cloacal tail length (PTL) is measured from midcloacal opening to the end of the tail. We measured also the distance from posterior tip of sopracaudals to the edge of the tail. Flipper length (FL) is measured on fore flipper from the elbow to the edge of the fore flipper. All measures were taken with the turtle lying on its plastron, except TTL and PTL, that were taken with the turtle lying on its plastron. During measurements the anterior and posterior locations were on the same side. 40 LIFE NATURE PROJECT CARETTA CARETTA