Potential feminization of Red Sea turtle hatchlings as indicated by in situ sand temperature profiles
Type
ArticleKAUST Department
Biological and Environmental Sciences and Engineering (BESE) DivisionEnvironmental Science and Engineering Program
Marine Science Program
Red Sea Research Center (RSRC)
Red Sea Research Center, Division of Biological and Environmental Science and EngineeringKing Abdullah University of Science and Technology Thuwal Saudi Arabia
Reef Ecology Lab
Date
2020-09-04Online Publication Date
2020-09-04Print Publication Date
2020-10Submitted Date
2020-03-22Permanent link to this record
http://hdl.handle.net/10754/665052
Metadata
Show full item recordAbstract
Climate change poses a serious threat to species that demonstrate temperature-dependent sex determination, including marine turtles. Increased temperatures can result in highly female-skewed sex ratios and decreased hatching success. The pivotal temperature that delineates hatchling sex ratios is commonly considered to be 29.2°C, but whether this threshold applies to turtles in the Red Sea region has not been tested in situ. For all species of marine turtles, there is a supposed thermal range of 25–33°C in which egg incubation is successful, with prolonged temperatures above 33°C resulting in morphological abnormalities and hatchling mortality. Sand temperature data were collected from May–September 2018 from the average nesting depth of hawksbill (Eretmochelys imbricata) and green turtles (Chelonia mydas) at five study sites. We calculated the expected sex ratio based on a maximum likelihood model. The sand temperature profile at four of the sites exceeded the pivotal temperature (29.2°C) throughout the study duration, which suggests feminization of turtles could be occurring; however, the pivotal temperature in this region still needs to be empirically confirmed. The percentage of days with sand temperature exceeding the maximum thermal threshold between June 3, and September 16, 2018, was site-specific rather than determined by latitudinal temperature gradients, and ranged between 0 and 100% of days. Maximum temperature recordings were as high as 36.0 and 35.3°C at 30 and 50 cm depth, respectively. Nesting sites in the Red Sea region could already be exceeding the thermal limits and may be particularly vulnerable to rising temperatures. Sites with lower sand temperatures, such as Small Gobal Island, may represent priority areas for conservation efforts. Alternatively, local adaptation may be a reality under extremely warm conditions, thus, further research into the thermal tolerance of hatchlings in the region could provide insight on how they might adapt to future climate change.Citation
Tanabe, L. K., Ellis, J., Elsadek, I., & Berumen, M. L. (2020). Potential feminization of Red Sea turtle hatchlings as indicated by in situ sand temperature profiles. Conservation Science and Practice. doi:10.1111/csp2.266Sponsors
Thanks to the members of the Reef Ecology Lab for assistance in the field, especially Royale Hardenstine, Ann Marie Hulver, and George Short. Thanks also to Irene Salinas Akhmadeeva for the turtle illustrations. This work was supported by the King Abdullah University of Science and Technology (KAUST) through KAUST's Red Sea Research Center and baseline funding to M. L. B.Publisher
WileyDOI
10.1111/csp2.266Additional Links
https://onlinelibrary.wiley.com/doi/abs/10.1111/csp2.266ae974a485f413a2113503eed53cd6c53
10.1111/csp2.266
Scopus Count
Except where otherwise noted, this item's license is described as This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, providedthe original work is pro perly cited.