Odisha's Rushikulya sees surge in female Olive Ridley turtles, dwindling male population raises concerns

A recent study has revealed a significant gender imbalance amongst Olive Ridley sea turtle hatchlings, with a dominant female population emerging at Rushikulya in Odisha's Ganjam district. The study showed the sex ration of newborn turtles tilting more towards females.

This research titled 'Monitoring Sea Turtles in India 2008-2024' was led by the Indian Institute of Science (IIS) in Bengaluru alongside the Dakshin Foundation, Bengaluru. Notably, 71% of the hatchlings at Rushikulya are female, marking a potential threat to the species’ demographic stability.

Unlike humans, sea turtles do not have sex chromosomes. Their sex is determined by the temperature of the sand where their eggs incubate, a phenomenon called temperature-dependent sex determination (TSD).

Research and Migration Patterns

Renowned turtle biologist B C Chaudhury, formerly with the Wildlife Institute of India, spearheaded this research. The investigation has yet to encompass Gahirmatha Sanctuary, identified as the world's largest nesting ground for olive ridley turtles.

“Being polygamous male sea turtles can mate with a maximum of two to three female turtles for which falling numbers of male turtles will be a disaster for the turtle population,” Chaudhury revealed.

Movement of Olive Ridley Turtles:

Contrary to prior beliefs, the findings suggest these turtles rarely stray far from the Odisha coast. The study has found that these delicate marine animals do not travel far off as it was being speculated.

While some of the turtles remain in the offshore sea waters of Odisha, others migrate to Sri Lanka and the Gulf of Mannar.

The Arribada Phenomenon

The mass-nesting of Olive Ridley sea turtles, otherwise called arribada, is an annual ritual that takes place at Gahirmatha, Rushikulya and Devi river mouth beaches in Odisha.

An Olive Ridley usually lays about 120 to 150 eggs from which hatchlings emerge after about 45 to 50 days. But not all eggs remain intact as predators devour it. Besides, eggs are also washed away by sea waves during high tide. The eggs are incubated in the nest and grow, sans mother, to emerge as hatchlings.

This year, more than six lakh turtles had invaded the beach at Gahirmatha to lay eggs while the rookery at Rushikulya in Odisha played host to seven lakh turtles for en-masse nesting.