Climate change is turning sea turtle populations female

  • 10/01/2018

Rising sea temperatures due to climate change are having a bizarre and potentially catastrophic effect on the sea turtle population.

A paper published yesterday in Current Biology has found that populations of green sea turtles in the northern region of the Great Barrier Reef are now "overwhelmingly female".

Green sea turtles have 'temperature dependent sexual determination', which essentially means that their gender at birth is based on surrounding temperature. This means eggs of this species hatch as females when in warmer temperatures.   

The paper titled, Environmental Warming and Feminisation of One of the Largest Sea Turtle Populations in the World, examined two genetically distinct populations of turtles on the reef, finding the northern group of about 200,000 animals was overwhelmingly female.

While the southern population was 65-69 percent female, in the northern area 99 percent of juveniles, 99 percent of subadults and 86 percent of all adults were female.

The paper states: "...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 researchers were unequivocal on what was to blame and the danger it poses: "It is clear that climate change poses a serious threat to the persistence of these populations."

This isn't the only environmentally damaging effect of rising sea temperatures on the reef, last year its 'death' was widely reported due to 'coral bleaching', a process by which coral turns white as it dies from heat. 

Scientific American reported last year that up to 93 percent of the reef now shows at least some level of bleaching.

The Chief of the World Wildlife Federation Australia responded to the study by telling the Guardian that this was yet another urgent call to action on climate change.