99% Of Great Barrier Reef Turtles Are Turning Female Due To Climate Change

Posted: Jan 12 2018, 10:07am CST | by , Updated: Jan 12 2018, 10:12am CST, in News | Latest Science News

 
99% of Great Barrier Reef Turtles are Turning Female Due to Climate Change
Credit: Michael Jensen/NOAA Fisheries

New study shows that warming temperatures are influencing sex ratio of one of the largest sea turtle colonies in the world

Reseachers have found that almost entire green sea turtle population living in the northern Great Barrier Reef is now female. Precisely, 86.8 percent of adult turtles, 99.8 percent of sub-adult turtles and 99.1 percent of juvenile turtles turned out to be female and warming temperature is to blame for this devastating trend.

Australia’s Great Barrier Reef harbors one of the largest sea turtle colonies in the world. But virtually no male turtles are being produced from their nests in the past few years. Without male members, the colonly could not sustain itself and may disappear forever.

Researchers have reached this conclusion after analyzing turtle eggs in the nesting beaches. Like many reptiles, the sex of the green sea turtles is determined by temperature and the eggs that are incubated at warmer temperatures are more likely to produce female hatchlings.

The ideal temperature for sea turtle populations where they produce 50 percent male and 50 percent female is about 29 degrees Celsius. However, the temperatures on islands in Australia's northern Great Barrier Reef have increased significantly since 1990s and are contributing to dramatic changes in sex ratio of turtles here. Even just a few degrees temperature rise is enough to unsettle this natural balance.

If the trend continues, it could lead to the risk of producing all females or perhaps embrynoic death in many sea turtle populations.

“It is deeply concerning, because if it continues we're going to start to lose the male population, (which is) essential for breeding and keeping those populations sustainable in one of the world's most important green turtle populations.” WWF Australia chief Dermot O'Gorman said.

For the study, reseachers analyzed more than 400 from two nesting populations in the Great Barrier Reef and revealed their different sex ratios. Researchres found that green sea turtles from cooler southern nesting beaches were about 65 to 69 percent female, but populations from warmer northern beaches were even more heavily female. Almost 99 percent of juvenile turtles warmer, northern Great Barrier Reef turned out to be female.

Although researchers have already known that warming temperatures alter the sex of sea turtle offspring, this is the first time they have directly documented the trend in a major wild population. The findings provide a new understanding of how warming temperatures are affecting sea turtle populations and how they will respond to climate change.

"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 lead study author Michael Jensen, a research biologist at NOAA Fisheries' Southwest Fisheries Science Center. "The disconcerting thing is that we can now see how changes in the climate could affect the longevity of this and other sea turtle populations around the world."

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Hira Bashir covers daily affairs around the world.

 

 

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