CHENNAI: The satellite tagging of Olive Ridley turtles along the Chennai coast commenced on Thursday, marking the start of a two-year scientific study aimed at tracking fine-scale movements and near-shore habitat use of the endangered marine species.
The project is being jointly implemented by the State forest department, Wildlife Institute of India (WII) and the Advanced Institute for Wildlife Conservation (AIWC), following administrative and financial sanction issued by the State government in August 2025.
According to the Government Order, the study titled “Tracking fine-scale movements and near-shore use of Olive Ridley turtles of the Tamil Nadu coast” will be carried out during the 2025–26 and 2026–27 nesting seasons with a total sanctioned outlay of Rs 84 lakh.
The research aims to identify critical near-shore breeding, foraging and congregation areas, map migratory routes, and generate data to regulate fisheries-related activities during the nesting period.
Mohit Mudliar, wildlife biologist from WII, said the satellite tagging would help answer long-standing questions about turtle behaviour off the Tamil Nadu coast.
“We want to understand whether turtles remain close to shore or move long distances, where they forage and mate, and how their movement patterns change before and after nesting,” he said.
The first turtle of the season was captured near the Adyar river mouth around 12:30 am and released by 5:30 am.
She was a healthy female weighing about 40–41 kilograms and carrying a clutch of more than 130 eggs, which indicates she is coming for nesting for the first time this season.
"So, we can expect her to come back again for nesting after a month. Initial satellite signals showed her swimming roughly six kilometres off the Chennai coastline,” Mohit said.
“The tags are different from GPS devices. They transmit data only when the turtle surfaces and the antenna clears the water,” he further explained.
While the tags are expected to function for four to six months, previous deployments have recorded transmissions lasting up to 212 days.
Additional Chief Secretary for Environment, Climate Change and Forests Supriya Sahu said the tagged turtle had nested at the Besant Nagar beach and appeared to be a first-time nester aged between 25 and 30 years.
“Hourly satellite data will help us identify turtle congregations, foraging and nesting areas. This will provide valuable scientific inputs for the forest department to strengthen turtle conservation strategies,” she said.
The Government Order notes that up to 20 Olive Ridley turtles are proposed to be satellite-tagged along the Tamil Nadu coast, with 10 tags earmarked for deployment along the Chennai coast alone.
The study also includes near-shore boat surveys, fisherfolk interviews to map high-risk fishing zones, and flipper tagging of 5,000 turtles to study nest-site fidelity and survivorship.
A second turtle, rescued after a fishing hook pierced her lower jaw and taken to Besant Memorial Animal Dispensary, was also tagged and released into the sea on Thursday night.
Vandalur Zoo veterinarian K Sridhar said the stainless steel hook had caused difficulty in mouth movement.
“Once the hook was removed, the turtle became very active. The injury will not hamper her feeding ability,” he said, adding that the turtle weighed around 35 kilograms and had laid eggs on Besant Nagar beach before being rescued.