Climate Change Affects Turtle Reproduction

A new study by researchers at Florida Atlantic University reveals the impact that climate change and a rise in sea levels is having on the reproduction patterns of sea turtles

Drought, heavy rainfalls and climatic changes are having an impact on hatchling sex ratios and influencing future reproduction. Because sea turtles don’t have an X or Y chromosome, their sex is defined during development by the incubation environment. Warmer conditions produce females and cooler conditions produce males.

The results of the four-year study on the effects of turtle nest temperatures and sand temperatures and on hatchling sex have just been published in the journal Endangered Species Research.

‘The shift in our climate is shifting turtles as well, because as the temperature of their nests change so do their reproduction patterns,’said Jeanette Wyneken, Ph.D., professor of biological sciences in FAU’s Charles E. Schmidt College of Science.

‘The nesting beaches along Florida’s coast are important, because they produce the majority of the loggerhead hatchlings entering the northwestern Atlantic Ocean.’

Loggerhead turtles are already fighting an uphill battle since roughly one in 2,500 to 7,000 sea turtles make it to adulthood.

‘If climatic changes continue to force the sex ratio bias of loggerheads to even greater extremes, we are going to lose the diversity of sea turtles as well as their overall ability to reproduce effectively. Sex ratios are already strongly female biased,’ said Wyneken. ‘That’s why it’s critical to understand how environmental factors, specifically temperature and rainfall, influence hatchling sex ratios.’

 ‘The majority of hatchlings in the sampling were female, suggesting that across the four seasons most nest temperatures were not sufficiently cool to produce males,’ said Wyneken. ‘However, in the early portion of the nesting and in wet years, nest temperatures were cooler, and significantly more males hatched. 

The work was supported, in part by the National Save the Sea Turtle Foundation, Save our Seas Foundation and donations to the Nelligan Sea Turtle Support Fund.