Biogeographia - vol. XXI - 2000 (Pubb/icato il 30 giugno 2000) Biogeografia de|l’Anato|ia Five years of research at Akyatan Beach (Turkey): one of the main nesting site for green turtle, Cbeloma my/a'a5, in the Mediterranean MONICA AUREGGI *, GUIDO GEROSA *, SEDAT V. YERLI ** *CHELONMarz'ne Turtle Comen/ation and Research Program, Viale Va/Padana, 134/B — 1-0014] Roma (Italy) **Department of Biology, Hacettepe University, P. O.B0x 40 — 06696 — Ankara (Turkey) Key words: Turkey, green turtle, C/Je/onizz my:/ax, Mediterranean, predation, nesting site. SUMMARY Alcyatan beach is located on the South East coast ofTurkcy in the Cukurova region. The beach, composed of fine sand, has a rather homogeneous aspect throughout its 19.7 k.m length. The area is still unaffected by human influences, apart from limited local tourism which is mainly concentrated during the weekends. In 1994, a long-term monitoring project was initiated at Alcyatan beach in order to investigate the area and to suggest a conservation strategy plan. As result of the first year of research, Alcyatan is the most important nesting site for green turtle in the whole Mediterranean. C/aelmzia myda: was always the predominant species, while the loggerheacl turtle, Caretta caretta, were such a low percentage that they do not represent a significative portion ofa population, compared with all other nesting places in the Mediterranean. From 1994 to 1998, yearly surveys were conducted along the entire beach during the breeding season, which was estimated to be from the end of May until October. The total number of marine turtle nests laid varied during the five years of research. It was similar in 1994 and 1995, then, a drastic decrease of about the same amount was recorded in 1996 and 1997, whereas a considerable increase was found in 1998. The spatial nest distribution within each ltilornetre along the beach resulted to be similar during 1994, 1995 and 1997 whereas in 1998 a different situation was observed. As natural predation resulted to be the main threat to the green turtle population, detailed analyses relating to its impact and distribution within a stretch offour kilometres, 14-17 km, were Carried out in 1995, 1997 and 1998. Predation rate during the egg incubation period varied during the three years. The number of predated nests was always similar, while the number of total nests laid was different. INTRODUCTION Akyatan was firstly cited as marine turtle nesting site by Geldiay (1982) and then its importance for green turtle was highlighted by Baran and Kasparek (1989). In 1994, a long—term monitoring project was initiated at Akyatan beach in order to investigate the area and to suggest a conservation strategy plan. The research focused each year on the entire length of the beach (20 km) in order to evaluate the nest distribution between years and detailed studies on natural nest