Sex ratio estimations of Chelonia mydas hatchlings at Samandağ Beach, Turkey

Authors : ŞÜKRAN YALÇIN ÖZDİLEK, BEKTAŞ SÖNMEZ, YAKUP KASKA

Pages : 552-560

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Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :Samandağ Beach, an important nesting location for endangered green turtles insert ignore into journalissuearticles values(Chelonia mydas);, is located at the most eastern part of the Mediterranean in Turkey. Hatchling sex ratio can be one of the key factors for green turtle protection, which is under the threat of global climate change. In this study, sex ratios of hatchlings were estimated by histological examination of dead hatchlings insert ignore into journalissuearticles values(n = 190); and by nest temperatures insert ignore into journalissuearticles values(n = 14); at Samandağ Beach between the 2003 and 2007 nesting seasons. The histological examination of dead C. mydas hatchlings and temperature-recorded nests indicated a female-biased sex ratio on Samandağ Beach. By histological examination, top and bottom levels of nests were recorded as 94% and 64% of females. Sex ratios during the middle third of the incubation period ranged from 39% to 97% for females with a mean of 74%. Distance from the sea was correlated with the middle third of incubation temperature insert ignore into journalissuearticles values(r = -0.604, P = 0.022); and female ratio insert ignore into journalissuearticles values(r = -0.573, P = 0.032);. While nest temperatures and nest parameters such as hatching success, clutch size, nest distance from the sea and from vegetation, nest depth, and the day of emergence were not found significantly different among years insert ignore into journalissuearticles values(P > 0.05);, incubation duration was found significantly different among years insert ignore into journalissuearticles values(P < 0.05);. The results showed a female-dominated sex ratio by both histology and nest temperature. The knowledge of hatchling sex ratios provides information on demographic parameters, and coupled with appropriate conservation measures this can make important contributions to studies of climate change effects on green sea turtle populations.
Keywords : Sex ratio, sand temperature, Chelonia mydas, green turtle, Samandağ