Assessing How Climate Change Affects Sea Turtle Hatchlings

SUMMARY: Researchers will study rising temperatures' impact on the hatch and the emergence success of nesting loggerhead and green sea turtles, including hatchling survival, growth rates and sex ratio changes.  

THE PROBLEM: For sea turtles, warmer nest temperatures result in more female hatchlings, and cooler temperatures produce more male hatchlings (“hot chicks and cool dudes”). Global temperatures are increasing, and sea turtle populations are rapidly becoming female-biased. In the short term, more females result in more hatchlings and, thus, more turtles. However, too few males could lead to fewer hatchlings and steep population declines over time. Also, hatchlings might not survive if the temperature rises too high, leading to a risk of extinction.  

THE PROJECT: Researchers will study nesting sites of loggerhead and green sea turtles in the Gulf of Mexico. Over two years, the team will track nest temperatures, nest depth, hatch/emergence success, and local and global weather data. Using this new information and earlier collected data, they will model whether nest temperatures and hatchling sex ratios change over time. The team also will test a method to decrease the temperature of loggerhead nests to improve the chance of producing more male offspring.  

POTENTIAL IMPACT: Nest sex ratios for sea turtles are already highly female-biased, as high as 90+% measured at one site on the east coast of Florida. Modeling data will help pinpoint factors significantly affecting nest viability and potential hatchling sex ratios. If the new method to decrease the temperature at nesting sites is successful, this much-needed conservation strategy could help improve the likelihood of a return to a more balanced sex ratio in new hatchlings and minimize the risk of extinction.