Climate change causing feminisation of green turtles, research suggests

Climate change causing feminisation of green turtles, research suggests

Up to 93% of green turtle hatchlings could be female by 2100 – as climate change causes “feminisation” of the species, new research suggests.

The sex of turtle hatchlings is determined by temperature, and at present about 52% of hatching green turtles – one of seven species of sea turtle – are female.

But a study by the University of Exeter and the Marine and Environmental Sciences Centre in Portugal shows that in warmer temperatures predicted by Intergovernmental Panel on Climate Change scenarios, 76% to 93% of hatchlings would be female.

The figures are specific to the study site in Guinea-Bissau (University of Exeter/PA)
The figures are specific to the study site in Guinea-Bissau (University of Exeter/PA)

The figures are specific to the study site in Guinea-Bissau, West Africa but researchers say they expect a similar picture globally.

They say the changing gender ratio would initially lead to more females nesting, increasing the population, before a decline “as incubation temperatures approach lethal levels”.

They also predict rising sea levels will submerge 33% to 43% of current nesting areas used by green turtles on the beaches where the study was carried out.

“Green turtles are facing trouble in the future due to loss of habitats and increasing temperatures,” said Dr Rita Patricio, from the University of Exeter.

“Our results suggest the nesting population of green turtles on the Bijagos Archipelago, Guinea-Bissau, will cope with the effects of climate change until 2100.

“Cooler temperatures, both at the end of the nesting season and in shaded areas, will guarantee some hatchlings are male.

“Although rising temperatures will lead to more female hatchlings – and 32% to 64% more nesting females by 2120 – mortality in eggs will also be higher in these warmer conditions.

“As temperatures continue to rise, it may become impossible for unhatched turtles to survive.”

Hatchling green turtles emerging from nests at Poilao Island (University of Exeter/PA)
Hatchling green turtles emerging from nests at Poilao Island (University of Exeter/PA)

The research team says nesting sites submerged by rising seas may not simply “move” inland.

“Beach retreat may be OK in some areas but the turtles we studied were nesting on the small island of Poilao so there is a limit to how far the beach can go,” Dr Patricio said.

“In other places there may be natural barriers or human constructions that stop beaches moving inland.”

The Bijagos Archipelago is the most important nesting place for green turtles in Africa, and the main breeding ground for the species in the South Atlantic.

– The paper, Climate change resilience of a globally important sea turtle nesting population, is published in the journal Global Change Biology.

- Press Association

More on this topic

Climate change should not have its own department, says MartinClimate change should not have its own department, says Martin

Forest elephants are our allies in the fight against climate change, finds researchForest elephants are our allies in the fight against climate change, finds research

Clear glass solar panels ‘could charge mobile phones and electric cars’Clear glass solar panels ‘could charge mobile phones and electric cars’

Humans generated 1.8bn tonnes of solid waste in 2016Humans generated 1.8bn tonnes of solid waste in 2016

More in this Section

Teenage drill rapper Unknown T appears in court charged with murderTeenage drill rapper Unknown T appears in court charged with murder

Iran’s Revolutionary Guard forces ‘seize tanker accused of smuggling oil’Iran’s Revolutionary Guard forces ‘seize tanker accused of smuggling oil’

Donald Trump leans into issue of race in bid for 2020 re-electionDonald Trump leans into issue of race in bid for 2020 re-election

Live animal testing at lowest level since 2007Live animal testing at lowest level since 2007


Lifestyle

Breanndán Ó Beaglaoich will not let a day pass without his ritual dip in the sea, which he describes as the best anti-depressant ever, says Lorna Siggins.Taking the plunge has a depth of benefits

10% of women suffer from it worldwide.As Alexa Chung reveals she has endometriosis, here’s everything you need to know about the condition

Pinnies, cookie cutters and wooden spoons at the ready.Food projects to do with the kids this summer

Stop. Climbing. Uluru.As tourists rush to climb Uluru despite an incoming ban – 5 ways to enjoy the rock respectfully

More From The Irish Examiner