These majestic creatures are losing out in climate change, why every little step we take matters now! –
A new study reveals increasing temperatures are turning green turtle populations almost completely female in the northern Great Barrier Reef (GBR). The Current Biology paper says the northern GBR population of more than 200,000 nesting females—one of the largest in the world—could eventually crash without more males. Increasing temperatures in Queensland’s north, linked to climate change, are being blamed because the incubation temperature of eggs determines the sex of turtles with a warmer nest resulting in more females.
There are two genetically distinct populations of green turtles on the reef. One population breeds at the southern end and the other nests in the far north, mostly at Raine Island and Moulter Cay. Scientists caught green turtles at the Howick Group of islands where both populations forage. Using a combination of endocrinology and genetic tests, researchers identified the turtles’ sex and nesting origin.Of green turtles from warmer northern nesting beaches, 99.1 percent of juveniles, 99.8 percent of subadults and 86.8 percent of adults were female. Turtles from the cooler southern GBR nesting beaches showed a more moderate female sex bias (65 to 69 percent female).
Lead author Dr. Michael Jensen, from the National Oceanic and Atmospheric Administration (NOAA), said northern GBR green turtle rookeries have been producing primarily females for more than two decades resulting in “extreme female bias.”