Global Warming: Female Population of Sea Turtles Will Increase due to Rising Temperatures

Sea turtles are one of the many species bearing the brunt of the impact of climate change as a new study reveals that rising temperatures will lead to production of only females.

Reproduction in reptiles is highly temperature sensitive and sea turtles in particular incubate at a specific temperature and a high temperature means only girls will hatch.

In sea-turtles, the critical temperature needed is 29 degrees C for incubation, and temperature beyond 29 degree C increases the likeliness of female hatchlings. At 30.5 degree C the sea turtle population will be all girls, according to The Sydney Morning Herald.

Researchers at Swansea University Prifysgol Abertawe and Deakin University Australia, claim that the sands getting hotter with rising global temperature could cause the production of just females leading to the possibility of the species becoming extinct due to climate change.

 "The possibility of sea turtles becoming extinct is not a far-fetched scenario," said Professor Graeme Hays. "Above a certain pivotal incubation temperature, typically near 29°C, the majority of sea turtle eggs produce female hatchlings and vice versa. Warming temperatures therefore, occurring as part of global climate change, may cause the feminisation of sea turtle populations through the production of only female hatchlings."

In this study the researchers estimated the past, present and future sex ratio for one of the world's largest sea-turtle rookeries- the Cape Verde Islands, Atlantic. A large number of loggerhead turtles are known to breed here.

The sand temperature for several years was recorded using small data-loggers. This data was later combined with the past measurements of environmental condition on the island since 1850 and they also made the climate prediction for the next 100 years with the help of the Intergovernmental Panel on Climate Change.

For the first time the researchers have used data on breeding periodicity that was gathered by satellite tagging to reveal the tendency of males to breed more frequently than females.

"This shows that males are more likely than females to breed in successive years, because females invest so much to produce eggs and lose so much body condition that it takes several years for them to recover," Professor Hays adds. "It means that even though the hatchling sex ratios are skewed in favour of females, the operational sex ratio is much more balanced with more females ready to breed in a given year thus giving the unexpected conservation benefit of increasing the number of breeding females and hence the total size of the population."

The good news is that the feminisation of the sea turtle population is not imminent.

 The finding was documented in the journal Nature Climate Change.