Published: Wed, January 10, 2018
Research | By Jennifer Evans

Green turtles face extinction

Green turtles face extinction

"With average global temperature predicted to increase 4.7 Fahrenheit (2.6 Celsius) by 2100, many sea turtle populations are in danger of high egg mortality and female-only offspring production", it added.

A recent global by the University of Exeter found that more than 1,000 marine turtles were dying after becoming entangled in rubbish every year, while another found that 90% of young green turtles had plastic waste in their gut.

Less than one per cent of the juvenile green sea turtles in the northern Great Barrier Reef are now male, which is a huge concern for conservationists.

The study analyzed more than 400 turtles and was conducted by researchers from the U.S. National Oceanic and Atmospheric Administration, as well as the Queensland Department of Environment and Heritage Protection in Australia. Volunteers and with Fish and Wildlife wardens released hundreds of turtles back into the sea that had washed ashore recently, "cold stunned", far too chilled to swim, because of the massive fall in sea temperatures in some bays around the state, according to local reports. Just a few degrees can mean the difference between a balanced and skewed sex ratio.

The research examined two genetically distinct populations of turtles on the reef, finding the northern group of about 200,000 animals was overwhelmingly female.

Specifically, 99.1% of juveniles, 99.8% of subadults, and 86.8% of adults in the population were female. Turtles from the cooler southern GBR nesting beaches showed a more moderate female sex bias (65 to 69 percent 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 impacts of rising temperature are particularly pertinent in species with temperature-dependent sex determination (TSD), where the sex of an individual is determined by incubation temperature during embryonic development", the researchers explained.

For now, the important matter is to look into the current sex ratios in the adult breeding population, and what they might look like after some years from now when these young turtles grow up, Jansen stated. The species is already considered endangered throughout much of the world.

"Australia must adopt ambitious climate change targets that will save the Reef and its unique creatures".

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