Female Hatchling Surge Alarms Olive Ridley Experts in Odisha

Ganjam: A recent scientific study has uncovered a worrying gender imbalance among Olive Ridley sea turtle hatchlings at Rushikulya rookery in Odisha’s Ganjam district, raising concerns about the long-term survival of the species.

The research, titled “Monitoring Sea Turtles in India 2008–2024,” was conducted by the Indian Institute of Science (IISc), Bengaluru, in collaboration with the Dakshin Foundation. Findings from the study revealed that 71% of the hatchlings at Rushikulya are female, indicating a skewed sex ratio that could threaten the species’ demographic stability in the coming years.

Unlike humans, sea turtles do not have sex chromosomes. Their sex is determined by the temperature of the sand where the eggs incubate—a natural phenomenon known as temperature-dependent sex determination (TSD). With rising global temperatures, scientists fear a consistent rise in female hatchlings could destabilize breeding patterns.

Renowned turtle biologist B.C. Chaudhury, formerly with the Wildlife Institute of India, led the research. He warned that declining numbers of male turtles pose a serious threat to the species, stating, “Male turtles are polygamous and can mate with only two to three females. A continued drop in their numbers could prove disastrous.”

The study also provided new insights into the migration behavior of Olive Ridleys. Contrary to earlier beliefs, the turtles seldom travel far from the Odisha coastline. While some remain in local offshore waters, others migrate to regions such as Sri Lanka and the Gulf of Mannar.

Notably, the research has yet to include Gahirmatha Sanctuary—the world’s largest nesting site for Olive Ridley turtles.

The mass nesting phenomenon, known as arribada, continues to draw hundreds of thousands of Olive Ridley turtles to Odisha’s shores annually. This year, over six lakh turtles nested at Gahirmatha, while Rushikulya recorded around seven lakh nesters.

Each Olive Ridley lays approximately 120 to 150 eggs per nesting season. However, not all eggs survive. Many fall prey to predators or are swept away by high tides. The hatchlings incubate independently in sandy nests and emerge after 45 to 50 days.

The findings underscore the urgent need for climate-responsive conservation measures to protect the ecological balance and ensure the survival of this vulnerable marine species.