MEDASSET'S 1990-91 RESEARCH CONCLUSIONS FOR ΤΗΕ ENDANGERED MEDITERRANEAN SEA TURTLE E.F. Salter Park Wood, Pare Lane, Knebworth, Herts SG3 6ΡΡ UK Presented by Lily Venizelos INTRODUCTION The threats to the survival of the marine turtle in the Mediterranean are no different than those in the rest of the world; loss of habitat to tourism, injury and death via fisheries, pollution of the sea and direct human predation has put their very existence in these waters at jeopardy. Mediterranean Association to Save the Sea Turtles (MEDASSET) recognised these problems and placed emphasis on field research on a broad number of topics for 1990 and 1991. It was a very busy period, and five research projects were carried out. Sadly, in too many cases the "success" of the project was only in confirming that nesting was not successful, mainly due to human interaction. PROJECTS Α survey of all potential nesting beaches and sand dune status on the mainland and islands of the North Aegean Sea, Greece. Nesting in the North Aegean Sea has apparently never been proved, though there are many reports that turtles occur there. Furthermore, the finding of several leatherbacks (Dermochelys coriacae) started speculation as to whether this species might even breed somewhere in the region. The aim of the research project was to survey this, the remaining outstanding Greek coastline, for the incidence of marine turtle nesting, and to prioritise that areas for marine turtle conservation. The North Aegean coast from Macedonia and Thessalia in the west, to the Turkish border in the east, including four islands, was surveyed for sea turtle nesting in the summer of 1991. 2078km of coastline with a total of 213 beaches comprising 664km, were surveyed. Forty-nine beaches with a total of 140km looked to the experienced eye, always α subjective decision, like possible nesting beaches. Another 42 beaches (150km) looked like less suitable, but still possible, nesting beaches. In total, only one false crawl was found on the island of Limnos. Therefore it can be stated that no significant breeding occurs in the North Aegean; this in turn confirms the importance of key nesting beaches in the Ionian Sea (Greece), the Turkish Mediterranean coast and along the Cypriot coast. The reasons for the lack of nesting turtles in the North Aegean is thus not a lack of suitable habitats. The reason could be climatic. Α study was made to compare the climate of the nesting and non-nesting sites in Turkey and Greece. The Aegean region is a transition area between the Mediterranean climate of the eastern Mediterranean and the continental climate of Bulgaria. The duration of the hot season is decisive for sea turtle nesting. The summer may be too short for the successful establishment of a sea turtle population in the North Aegean Sea. If occasional nesting does occur the population size must be said to be unimportant compared to those others found in Greece and Turkey. Several small loggerhead turtles, Caretta caretta, were found dead washed ashore (ccl <40cm for four specimens and <67cm for two others), and interviews with local people brought some information. It became evident that the North Aegean holds an important sub-adult, non-nesting population of loggerhead turtles. They may come from Turkish and Greek nesting localities because both areas are equidistant from the North Aegean. All loggerheads were found in the eastern half of the study area, and also all reports of local people refer to this location. The reason may be that there is a very large area of shallow sea providing a rich, relatively warm feeding ground with extensive sea grass beds. Almost all of the 213 beaches were polluted in some way, most commonly with litter washed ashore, but also sewage and oil leaking from barrels was noted. Α detailed inventory of all the beaches and sand dunes was made. Α nesting beach and sand dune assessment of Sardinia (with emphasis on the Gulf of Orosei), and an investigation of reported exploitation of loggerheads, Caretta caretta.
Loggerheads are regularly recorded around the southern Italian coast and Sicily, but females are reported to nest there only once or twice per season. This area of the Mediterranean is also witnessing many intentional and accidental turtle captures by fishery operations based in Italy, Tunisia and especially Malta. It was therefore considered urgent to conserve any surviving nesting habitats in order that some recruitment might offset losses of such α slowly maturing species. This initial short term study was designed in the absence of any previous comprehensive survey for nesting in Sardinia; and in the light of increasing uncontrolled tourism. Eastern and south-western Sardinia were surveyed during mid-summer in 1990 and 1991. This time of year was chosen to try and enhance the possibility of finding tracks, nest pits or hatchlings. Again a subjective method of defining suitable nesting beaches was used. Physical suitability, the type of development and the density of daytime visitor use were the three parameters in the categorisation. Α detailed inventory of the sand dunes was also made. No evidence of current nesting was found, and significant breeding populations are unlikely to be present. However, daytime tourist pressures on many beaches greatly reduced the chances of locating low density nesting. Increasing tourism is rapidly destroying nesting potential, but 5 particularly good beaches were identified and need more detailed study. The continuing local presence of adult and sub-adult loggerheads offshore was confirmed particularly around the Gulf of Orosei. Whether low level nesting still occurs in Sardinia by loggerheads has yet to be ascertained, but any such recruitment could prove crucial for their stocks in the western Mediterranean. The first ever survey of the entire coastline of Syria for the occurrence of green and loggerhead turtles. Along the Syrian coast four areas were found that could, in principle, provide nesting facilities for both Chelonia mydas and Caretta caretta. The Syrian coastline was found to be amongst the most severely polluted in the Mediterranean, with plastic rubbish forming a 30cm thick layer on the sand and in the splash line. Sewage pipes ran directly into the sea, and the water was usually dark gray to black and covered with floating garbage. Only some 20-30m from the shore did the water become blue. The one area with significant nesting was between Jeble and Latakia in the centre of the Syrian coast. On June 22, 1991, scientists surveyed the 15.5km beach and found 24 fresh tracks. Four of the tracks were false crawls, two were unclear as to whether nesting had occurred, and the remaining 18 had nested successfully. All the nests had been opened by predators. Surprisingly there were no egg shell remains or tracks. The predator may be human. Upon a second visit three days later another five tracks were found. Again all the nests had been opened. The Latakia-Jeble beach should be protected from tourist or industrial development and the nests should be protected from human exploitation. Α further recommendation is that the Syrian government should be offered international support to solve the immense garbage and sewage problem that occurs along its coast. Incidental catch of loggerhead turtles on swordfish long lines in Greek Ionian waters. Most research over the last decade in the Mediterranean Sea concerning sea turtle conservation has been on nesting beaches. However, very little is known about the threats in the turtle's principal habitat, the sea. One major threat is long line swordfishing. Many turtles may survive this experience, and the actual mortality so caused is unknown, but estimates have been between 15 and 50%ο. The data shows considerable catches, but the information is very incomplete, particularly that for the Ionian Sea. The need for further data is evident in order to assess the impact of the swordfish fisheries on this long-lived species in one of its most important nesting areas. Monitoring of incidental catches of turtles in the central and southern Ιοnian Sea continued during the fishing season for swordfish, May-Sept., in 1990. The data were collected and evaluated by the captains of three vessels and biologist Αliki Ρanou. All fishing trips and catches were recorded. The size of caught turtles was estimated and, whenever possible, their sex recorded. All turtles were released alive with the hooks in the mouth cavity by cutting the nylon line while hauling in. Of the 171 registered fishing trips, 43 of them caught 49 turtles. All of them were loggerheads. The size of the animals varied between 20cm and 70cm. Only one turtle was of adult size, about 100cm. No significant difference in the frequency of catches was found between the northern part of the study area, where there is no known nesting, and in the south where the largest known concentration of turtles nesting in the Mediterranean Sea occurs. Although the data are incomplete, the monthly frequency of catches per fishing trip indicates that most of them occur during the nesting period from May to August. Α major factor for the conservation of turtles is the attitude of the fishermen. Among the Greek captains working on the swordfish boats, the attitude is very
positive towards the turtles, and they are keen to participate in the research efforts. Another severe threat to the loggerhead's population is most likely posed by drift nets which are heavily used not far from the study area. The data have shown that most of the turtles caught on the swordfish lines were relatively small. This may indicate that the adult fraction has decreased due to death in drift nets. The use of such fishing methods may prove fatal to the species, combined with long line catches and the loss of nesting sites in one of the main loggerhead breeding areas. Α conservation assessment of the South West Pelleponese, Greece, for Caretta caretta. The status of Caretta caretta in the Mediterranean, as estimated by Groombridge 1989 and UΝΕΡ 1989, suggests that between 3000-4000 nests are laid on Mediterranean beaches each year. Α major percentage of these nests are laid in the Laganas Bay area of Zakynthos. The SW Pellepponese coast is directly Southeast of Zakynthos Island, less than 100km away. Loggerhead nesting has been recorded in Kiparissia since 1987 by the Sea Turtle Protection Society of Greece. Α 3km area of particularly high density nesting was found along the 44km of sandy beaches in the bay. Α total of 598 nests were recorded from the bay during the 1987 season. This study is concerned with the current and potential impact of tourism and other development in the SW Pellepponese on the conservation of the loggerhead through disturbance or damage to the nesting areas and breeding grounds. The study provides an assessment of potential hazards to breeding turtles in the areas found to be used by C. caretta and identifies the areas with greatest priority for protection in terms of having the greatest numbers of nests. The beach between Kalonero and Bouzi was found to be the most important section of the coast as regards numbers of nests, 94 in total representing 65% of nests seen on all sites. The highest density was 20 nests/km. In terms of the nest numbers, the area is clearly of less importance than Laganas Bay in Zakynthos, but a tagging program has been set up by the STPS and may answer the question of whether the populations of turtle rookeries nesting on Zakynthos and the Pellepponese are separate or interchangeable. At present the area identified here as being of most importance to turtle conservation is remote from any tourism development. Three hazards to the turtles were noted however; tracks of heavy vehicles and signs of sand mining; a rough road running along the back of the beach causing erosion of the protective sand dunes; and several nests destroyed by animals. The conclusions drawn from this research are that this area of the Pellepponese has not received the attention of the large scale tourism developers. However, the area provides attractive beaches and scenery, and this study was catalysed by reports of plans to develop sections of the coast. It is recommended that before development is permitted, in ΕΙΑ with special regard to its potential impact on the rookery should be carried out. CONCLUSION MEDASSET's conclusions can be none other than to keep up this vital assessment of the status of the marine turtle in the Mediterranean, not only to discover any as yet unknown nesting, feeding and over-winter sites, but to try and maintain and protect those areas already known to us that are in grave danger of being destroyed. We have learnt recently that this job is to become even more difficult. In the future, grants from the European Community (EC) are to be cut to only 50%ο of the total budget for research projects (previously, they provided 90%ο), leaving the penniless NGOs like MEDASSET to provide the other 50%. One recent glimmer of hope seen on the horizon is that the DGXIB Habitats Directive of the EC has included Caretta caretta as one of only six reptiles to be protected. Sadly Chelonia mydas does not get such protection because the main breeding sites of the species of turtle in the Mediterranean do not occur on the shores of EC countries. LITERATURE CITED Kasparek, Μ. (1991). Marine Turtle in Greece: Α survey of potential nesting beaches in the North Aegean Sea. EC (DGΧΙΒ)* Whitmore, C., R. Jesu, and Ρ. Reynolds (1991). Sardinia: An assessment of beaches for loggerhead turtle nesting. EC(DGXIB)* Baumgart, W., and Μ. Kasparek (1991). Sea Turtle in Syria. Results of a coastal survey** Panou, Α. (1991). Incidental catches of loggerhead turtles, Caretta caretta, on swordfish long lines in the Ionian Sea, Greece.**
Whitmore, C. (1990). Î‘ conservation assessment of South West Pelleponese, Greece for Caretta caretta** * EC requested MEDASSET to do this work. MEDASSET contacted name above and coordinated work. ** MEDASSET coordinated and sponsored these programs.
Published on Jan 1, 1995
Author(s): E.F. Salter. In: Richardson, J.I. & T.H. Richardson (Compilers). Proceedings of the 12th Annual Workshop on Sea Turtle Biology a...