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Warming turning major sea turtle population female: study

Press Trust of India  |  Melbourne 

Warming temperatures are turning one of the world's largest populations in Australia's almost entirely female, running the risk that the colony may not sustain itself in coming decades, a study has found. Sand temperatures determine the sex of turtle hatchlings, with warmer temperatures resulting in more females. During the past two decades, temperatures on islands in Australia's northern have increased to the point "that virtually no male turtles are now being produced from these nesting beaches," said researchers from National Oceanic and Atmospheric Administration (NOAA) Fisheries in the US. The study published in the journal Current Biology "raises new concerns over the immediate threats of climate change to populations". The will be important for wildlife managers as they consider strategies to lower incubation temperatures at key rookeries around the world. This may help "boost the ability of local turtle populations to adapt to the changing and avoid a population collapse or even extinction". Although researchers have known for decades that warming temperatures alter the sex of offspring, this is the first time they have directly documented the trend in a major wild population. The study used an innovative combination of endocrinology and genetics to assess the sex of hundreds of turtles across a large foraging ground, revealing the sex ratio of immature and mature turtles from different nesting beaches over many years. The analysis revealed different sex ratios and trends in two nesting populations in the Green sea turtles from cooler southern nesting beaches were about 65 to 69 per cent female, testing showed. Sea turtles from warmer northern beaches leaned even more heavily female, with 86.8 per cent of adult turtles, 99.8 per cent of sub-adult turtles, and 99.1 per cent of juvenile turtles turning out to be female. "This has given us an important new window into demographic changes in these populations over the last several decades, which have gone undetected until now," said Michael Jensen, a at NOAA Fisheries. "The disconcerting thing is that we can now see how changes in the climate could affect the longevity of this and other populations around the world," Jensen said. Green sea turtles are protected under the Endangered Species Act and listed as endangered on the International Union for the Conservation of Nature's Red List. The holds some of their largest populations in the world, researchers said.

(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)

First Published: Tue, January 09 2018. 17:40 IST