New research has found that rising temperatures are turning nearly all green sea turtles female in an area of the Great Barrier Reef.
The unbalanced ratio could threaten the future of the population, the scientific paper warned. It examined two genetically distinct populations of turtles on the reef and found that the northern group of about 200,000 animals was overwhelmingly female.
The southern population was 65%-69% female, females in the northern group accounted for 99.1% of juveniles, 99.8% of subadults and 86.8% of adults.
The paper, from the National Oceanic and Atmospheric Administration, California State University and Worldwide Fund for Nature Australia, is published in Current Biology.
The paper said: “Combining our results with temperature data show that the northern GBR green turtle rookeries have been producing primarily females for more than two decades and that the complete feminisation of this population is possible in the near future.
“Furthermore, extreme incubation temperatures not only produce female-only hatchlings but also cause high mortality of developing clutches,” it said. “With warming global temperatures and most sea turtle populations naturally producing offspring above the pivotal temperature, it is clear that climate change poses a serious threat to the persistence of these populations.”
According to the Guardian, ‘sea turtles are among species with temperature dependent sex-determination and the proportion of female hatchlings increases when nests are in warmer sands.’
The research was facilitated through the Great Barrier Reef Rivers to Reef to Turtles project by the World Wildlife Fund Australia.
Read more about the study here.
Turtle image from stock image library