Turtle sex change on unbalanced beaches
Researchers say some Australian turtle populations are at risk of being feminised into extinction.
As temperatures warm, turtles’ eggs become more likely to hatch female.
The phenomenon has been seen worldwide, and now a University of Western Australia (UWA) team is rushing to key turtle breeding areas to see which are most at risk.
“This is very fundamental research, and will give us insights fifty years ahead about whether sex ratios will change, where distributions might shift to, and what impact climate change is going to have,” team leader Nicki Mitchell told reporters this week.
“I don't think turtle populations are at risk of becoming extinct any time soon, because they live for a very long time, potentially 120 years. So the change is going to be slow.
“But the point is, climate change is very rapid compared to what turtles have experienced in the past, so our groups are trying to understand how rapidly they adapt.”
Research suggests that sex determination in turtles tips from male to female at just over 29 degrees Celsius.
So as beaches heat up across the globe, the implications for turtle rookeries could be massive.
“If it keeps getting warmer there are going to be more females being produced, and over time the males will keep dying at a greater rate than they are being replenished, so it's what's called demographic collapse,” researcher Blair Bentley said.
“There might still be males in the population, but there'll be far more females, and reproductive success will go down significantly.”
The team is looking at all sorts of methods to understand, slow or avoid turtle sex changes, including everything from shade cloths to genetic studies.
“We'd expect the turtles will find their own way to adapt, either genetically, or by changing when and where they breed,” Dr Mitchell said.
“But we just need to know how quickly that can occur, and if there are management implications for where industry wants to develop in the future, could that overlap with where turtles are holding on?”
The project is part of the State Government's $30 million Kimberley Marine Science Research Program, and should provide reports on work so far by the end of the year.