Caracteristiques topographiques et thermiques d'un site de ponte majeur de la tortue verte Chelonia mydas dans l'Ocean Indien sud-ouest: Europa

The beach of the meteorological station of Europa Island (Indian Ocean S.W.) is a major nesting site for the green turtle. Altimetric distribution of nests on the beach is such than 95 % of nests are laid in the band located between 1.25 and 3 m above the mean level of upper tides. Nest density is a function of adult females number and varies from 0.175 to 0.043 nest/m2 for the two analyzed nesting seasons. Ground temperatures at 60 cm and 100 cm depth range from 22 (winter) to, 30°C (summer). Interannual variability of ground temperature at same depth (incubation depth) is 1.5° C from extreme hot to cold years. These intra and interannual variations are supposed to have an effect upon the sex-ratio of hatchlings