Male sea turtles feel the heat

Things are heating up in Australia's northern tropics, but that's not good news if you're a sea turtle.
Sydney Morning Herald 6 May 09;

New research shows rising temperatures due to climate change will result in the feminisation of turtle populations, making males extremely rare.

James Cook University researcher Mariana Fuentes said that in just 20 years almost 90 per cent of turtle hatchings will be female.

"Basically by 2030 most of the hatchlings being produced are going to be female," she said.

"If you look down 60 or 70 years ahead if there's no male turtles being produced it could be a big problem."

The research was conducted in the Torres Strait and northern Great Barrier Reef, home to the largest green sea turtle population in the world.

The gender of sea turtles, as with other reptiles, is determined by water temperature.

Ms Fuentes said at an average temperature of 28 or 29 degrees, the ratio of male to female hatchlings was roughly equal but became skewed towards females as the temperature rose.

She said once the temperature rose above 33 degrees in the region, as is expected to happen by 2070, turtle eggs were not likely to develop at all.

The changes, along with a predicted rise in sea levels, would severely impact on turtle numbers in the region,

But Ms Fuentes said she believed the species would survive the changes.

She said it was likely turtle populations would eventually move south to cooler waters or breed earlier in the season.

"Sea turtles have been around for millions of years and have developed to past climatic changes," she said.

"I think they will probably adapt in a very slow way so there will be a reduction in numbers."

AAP