CHENNAI: The forest department has radio-tagged eight Olive Ridley turtles to better understand their movements, foraging behaviour and nesting patterns. Two more turtles are expected to be tagged in the coming days, expanding what scientists say is a crucial dataset for protecting one of India’s most threatened marine species.
The project is being implemented in partnership with the Wildlife Institute of India (WII) and tracks fine-scale movements of turtles released from Chennai’s near-shore waters. Early signals suggest that the turtles spend significant time close to the coast before venturing briefly into deeper waters.
“Immediately after release, we are seeing some turtles move 20-30km offshore, but over time they tend to come back closer to the coast,” said Mohit Mudliar, wildlife biologist from WII. “The first few turtles we tagged stayed within 10km of the shoreline. More recent ones initially went farther out, but the pattern of return is quite consistent.”
According to Mohit, the data may also help answer long-standing questions about Olive Ridley populations in the Bay of Bengal. “There could be multiple foraging strategies. Some turtles may stay near the coast, some may use deeper waters, some could even move towards Sri Lanka, and a few might cross over to the west coast. We don’t yet know how distinct these groups are,” he said, adding that turtles tagged on the east coast are generally considered a different sub-population from those nesting along Maharashtra, Karnataka and Kerala.
One tagged turtle rescued from Palavakkam with a fishing hook lodged in its mouth later nested near the mouth of the Palar river, south of Mahabalipuram, around 35-40km from where it was first encountered, indicating that while many turtles show nesting site fidelity, a significant proportion shifts locations.
Additional chief secretary Supriya Sahu said movement data has already begun coming in from five named turtles – Arasi, Kayal, Iniya, Malar and Aadhirai. “Early observations show turtles spending significant time close to shore and repeatedly returning to beaches to nest, highlighting the critical importance of undisturbed nesting habitats,” she said. “These preliminary insights will help identify congregation areas and strengthen science-based, collaborative conservation.”
Scientists also flagged the importance of keeping river mouths clean, noting that Olive Ridleys are often drawn to freshwater outflows, areas that can also funnel plastic and polluted discharges into the sea. While beach conditions have improved over the years due to clean-up drives and Blue Flag initiatives, researchers say reducing plastic and effluent flows from rivers like the Cooum and Adyar remain vital for turtle survival.