Green turtles face extinction
GREEN turtles could become extinct as alarming new research reveals up to 99 per cent of the reptiles are born female.
Warming temperatures in the northern Great Barrier Reef has caused the phenomenon and Australian and American scientists have warned if the trend continued it could result in a complete lack of male turtles, with extinction the worst case scenario.
The northern Great Barrier Reef is home to one of the largest green turtle populations in the world and a paper published in the Current Biology journal today has called for immediate management strategies to be put in place.
Researchers said lower incubation temperatures were necessary at key turtle rookeries along Queensland's coast to reduce the increasing number of female turtles.
The sex of sea turtle hatchlings is determined by the incubation temperature of the eggs laid in the sand - with the proportion of females rising as temperatures increase.
The study found that 65 to 69 per cent of green turtles in the cooler southern Great Barrier Reef were female while a "staggering" 87 to 99.8 per cent of green turtles in the warmer northern reef were female.
"Collectively, these results suggest that increased sand temperatures affect the sex ratios of the (northern Great Barrier Reef) population such that virtually no male turtles are now being produced from these nesting beaches," researchers wrote.
"While rising temperatures may initially result in increased female population sizes, the lack of male turtles will eventually impact the overall fertility of females in the population.
"Our study highlights the need for immediate management strategies aimed at lowering incubation temperatures at key rookeries to boost the ability of local turtle populations to adapt to the changing environment and avoid a population collapse - or even extinction."
The research also found an already low hatchling survival rate due to increasing water levels, altered weather patterns, and warming of habitat.
WWF-Australia CEO Dermot O'Gorman said shade cloth structures should be constructed on key nesting beaches such as Raine Island.
"First back-to-back mass coral bleaching and now we find that virtually no male northern green turtles are being born," Mr O'Gorman said.
"These impacts show that the Great Barrier Reef really is at the frontline of climate change.
"Australia must adopt ambitious climate change targets that will save the Reef and its unique creatures."