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ESR prepress abstract   -  DOI: https://doi.org/10.3354/esr01104

Feminization of hawksbill turtle hatchlings in the twenty-first century at an important regional nesting aggregation

Mark Chatting*, Shafeeq Hamza, Jassim Al-Khayat, David Smyth, Sinan Husrevoglu, Christopher D. Marshall

*Corresponding author:

ABSTRACT: Projected climate change is forecasted to have significant effects on biological systems worldwide. Marine turtles in particular may be vulnerable as the sex of their offspring is determined by their incubating temperature, termed Temperature dependent Sex Determination (TSD). This study aimed to estimate historical, and forecast primary sex ratios of hawksbill turtle, Eretmochelys imbricata, hatchlings at an important nesting ground. Incubation temperatures from the Arabian/Persian Gulf were measured over two nesting seasons in northeastern Qatar. Climate data from same period were regressed with nest temperatures to estimate incubation temperatures and hatchling sex ratios for the site from 1993 to 2100. Future hatchling sex ratios were estimated for two climate forecasts, one mid-range (SSP245) and one extreme (SSP585). Historical climate data showed female biased sex ratios of 73.2 ± 12.1% from 1993 to 2017. Female biases from 2018 to 2100 averaged 85.7% ± 6.7% under a mid-range scenario (SSP245) compared to 87.9% ± 5.4% under a high-range scenario (SSP585). In addition, predicted female hatchling production was >90% from 2054 and 2052 for SSP’s 245 and 585 respectively. These results show that hawksbill primary sex ratios in Qatar are at risk of significant feminization by the year 2100. These results show hawksbill turtle incubation temperatures in an extreme, understudied environment are already comparable to those predicted in tropical rookeries during the latter half of the 21st century. In addition, these results can help conservationists predict primary sex ratios for hawksbill turtles in the region in the face of 21st century climate change.