A new study has highlighted a notable gender imbalance among Olive Ridley sea turtle hatchlings at the Rushikulya rookery in Odisha’s Ganjam district, with a striking 71% of the young turtles identified as female.
This shift could pose serious long-term risks to the population dynamics of the species.
The research, spanning from 2008 to 2024, was conducted by the Indian Institute of Science (IISc), Bengaluru, in collaboration with the Dakshin Foundation. The findings draw attention to the critical role of temperature-dependent sex determination (TSD) — a process in which the ambient temperature of the sand during egg incubation dictates the hatchlings’ sex.
Biological Imbalance Raises Alarm
Unlike mammals, sea turtles do not possess sex chromosomes. Warmer sand temperatures tend to produce more female hatchlings, and this trend has intensified with rising global temperatures. With 71% of hatchlings being female at Rushikulya, experts warn of a looming threat to the species’ reproductive future.
Veteran herpetologist B.C. Chaudhury, formerly of the Wildlife Institute of India and lead contributor to the study, stressed that a declining male population could disrupt mating patterns. “Since male turtles can mate with only a few females, a shortage of males will severely affect population regeneration,” he explained.
Migration Myths Dispelled
The research also sheds new light on the turtles’ movement patterns. Contrary to earlier assumptions, Olive Ridley turtles mostly stay close to the Odisha coastline. While some venture to areas like the Gulf of Mannar and Sri Lanka, a large number remain within the state’s offshore waters.
The Annual Nesting Marvel
Odisha remains one of the most important global nesting grounds for Olive Ridley turtles, with mass nesting (arribada) observed annually at Rushikulya, Gahirmatha, and Devi river mouth beaches. Each female can lay between 120 and 150 eggs, but survival remains precarious due to predation, high tides, and natural loss.
The study has yet to include findings from Gahirmatha Sanctuary, the world’s largest nesting site for this species, suggesting that more comprehensive data may follow.
As climate patterns shift and coastal conditions evolve, researchers urge immediate conservation strategies to restore balance and ensure the long-term survival of this vulnerable marine species.
