Loggerhead sea turtles face an uphill battle when it comes to reproduction and population, with roughly one in 2,500 to 7,000 making it to adulthood. Although this species has been around for more than 60 million years, drought, heavy rainfalls, and climatic changes are impacting 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.
Researchers from Florida Atlantic University have just published the results of a four-year study in the journal Endangered Species Research (PDF), on the effects of turtle nest temperatures and sand temperatures and on hatchling sex.
“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.”
The typical loggerhead produces about 105 eggs per nesting season. That means one female would have to nest for more than 10 seasons over the span of 20 to 30 years just to replace herself and possibly one mate. Therefore, if enough males aren’t produced because of climate changes, this will result in a dire problem for this species.