Climate Change Could Be Responsible For Too Many Female Sea Turtles - via Herp Digest

By Lauren Leising   pastemagazine.com, April 18, 2017,

Every year, nearly 50,000 sea turtles lay their eggs on Florida’s beaches. Researchers monitor each new generation of sea turtles closely to determine their health, especially as the environment changes and external factors impact wildlife populations.

One significant change that has occurred in the sea turtle populations is the shifting sex ratio as more female turtles are born than males. Over the last few years, scientists have noticed an overwhelming number of female hatchlings on Florida’s coast, almost 95 percent of hatchlings were females in some cases.

Warming temperatures may be a driving factor behind the changing ratios. Unlike many other animal species, sea turtles’ sex is not determined by chromosomes but by environmental factors like temperature. In warm conditions, hatchlings are more likely to develop as females, whereas cool conditions are more conducive to producing male turtles.

Jeannette Wyneken and her colleagues at Florida Atlantic University have been studying the sea turtles on Florida’s beaches and have developed a method to predict the sex of turtles before they hatch by tracking environmental factors like temperature and a protein that is only found on female cells. Their goal is to aid in conservation efforts to protect the turtles and to forecast the ratio that will be present in each generation.

Concern that changing ratios could have devastating effects on turtle populations has caused conservationists to look to studies like that of Wyneken and her team to understand what factors impact the animals most strongly.

However, it is not clear if the unbalanced sex ratio is truly abnormal or if it really will have significant impacts on turtle species as a whole. David Godfrey, executive director of the Sea Turtle Conservancy, notes that, while the study does provide useful information regarding how rising temperatures plays a part in determining sex, it should not be used as a reason to manipulate sex ratios.

It is not clear if a 50-50 male-to-female ratio is really healthy for these species, and it will take more study to determine what the healthy ratio is, he told Scientific American. Understanding the effects of environmental factors like temperature is valuable but more research is necessary to see how the animals will be impacted long-term.