Warming seas are turning male turtles into females, scientists have discovered.
Researchers said climate change poses a ‘serious threat’ to animals, whose sex depends on the temperature at which the egg has been incubated.
Most green sea turtles monitored in the Great Barrier Reef are female and have been for more than two decades, marine scientists found.
Ninety-nine percent of young green sea turtles tracked to warmer nesting beaches and up to 69 percent originating from cooler beaches were female, research published in the journal Current Biology said.
Scientists said: ‘Combining our results with temperature data show that the (warmer) northern GBR (Great Barrier Reef) green turtle rookeries have been producing primarily females for more than two decades and that the complete feminisation of this population is possible in the near future.’
The experts said it is the first time the animals have been tracked to their nesting beaches, using a method combining genetic markers and hormone analysis to determine their gender.
Cooler temperatures were found to produce more male hatchlings while warmer saw more females hatched.
The so-called pivotal temperature, which produces a 50/50 gender split, can be passed down from parent to offspring, but the range which would result in all-male or all-female varies by only a few degrees, scientists said.
The research warned: ‘With warming global temperatures and most sea turtle populations naturally producing offspring above the pivotal temperature, it is clear that climate change poses a serious threat to the persistence of these populations.’