Relationship between Metabolic Heating and Nest Parameters in Green Turtles (Chelonia mydas, L. 1758) on Samandağ Beach, Turkey.

Abstract

Acquiring information about metabolic heating is necessary for the improved understanding of nesting beaches. However, there are limited studies on metabolic heating of green turtle (Chelonia mydas, L. 1758) on Mediterranean beaches. The present study sought to determine the metabolic heating, and its effect on the feminization of green turtle hatchlings during 2016 and 2017 nesting season on Samandağ Beach, Hatay, Turkey. Moreover, the relations between metabolic heating and nest parameters, and spatio-temporal differences of metabolic heating were evaluated. Nest temperatures were recorded by using data loggers placed at the center of nests (n = 18), and the same depth was used to determine the sand temperature that was 50 cm back of the egg chamber. The mean incubation duration was calculated as 51.1 days, and the mean distance of nests from sea and the mean nest depth were measured as 32.4 meters and 67.70 cm, respectively. The mean numbers of embryo that is early, middle and late embryonic stages were found as 110.8, 93.2 and 93.05, respectively. The mean clutch size was found as 110.8. Mean metabolic heating was 0.37°C in the middle third of incubation for both years. The metabolic heating in both years was close to the as reported in the other green turtles nesting beaches in the Mediterranean. The feminization effect of metabolic heating was calculated as 6.8% in the green turtle nests on Samandağ Beach. Metabolic heating did not vary spatially, and the clutch size was the most important factor in metabolic heating and explained a large proportion of the variation in metabolic heating.