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Journalism of Courage
EARLIER THIS year, volunteers of the Maharashtra forest department found a solitary turtle nesting at Ratnagiri’s Guhagar beach. On closer examination, they found two glistening metal tags, one on each of its front flippers. Almost immediately, the Olive Ridley turtle had an identity – 03233 – and a back story.
The turtle, researchers found, had made a long, arduous journey of nearly 4,500 km – starting from Gahirmatha in Odisha, down the east coast, possibly taking a bend around Sri Lanka, going up to Jaffna in the north, turning around and travelling down to Thiruvananthapuram before powering further up along the west coast and finally reaching the shores of Ratnagiri. Here, on the white sand beach of Guhagar, the turtle settled down to nest, laying 125 eggs, of which at least 107 have since hatched.
The flipper tags, bearing the number 03233, revealed that the turtle had been tagged by the Zoological Survey of India (ZSI) on March 18, 2021, at Odisha’s Gahirmatha Marine Wildlife Sanctuary. The turtle was one of 12,000 Olive Ridleys that got the tags clipped on to their flippers (the four flattened limbs that help turtles swim and which they use during mating and nesting) that year to help researchers track their migration patterns and areas of foraging.
According to the researchers, this is the first such migratory feat recorded among Olive Ridley turtles, which are known to be excellent navigators.
Dr Suresh Kumar, senior scientist at the Wildlife Institute of India (WII) in Dehradun, who has studied the movements and migration of Olive Ridley turtles as part of his doctoral research, says the turtle’s journey took him by surprise. “I never imagined that the turtle could come all the way from the east coast to the west coast. While it may not be a rare occurrence, this is perhaps the first recorded instance of a turtle tagged on the eastern coast being discovered on the west coast. We never knew that such a migration was possible among the species.”
Dr Kumar says that while scientists “strongly believe” the turtle took the 4,500-km route around Sri Lanka, a known foraging ground for Olive Ridley turtles, “it’s possible that it took an alternative, shorter route through the Pamban corridor” that links the island of Rameswaram to mainland Tamil Nadu.
ZSI’s Dr Basudev Tripathy, who tagged Turtle 03233, says that its discovery on the shores of Ratnagiri in Maharashtra throws new light on the nesting patterns of Olive Ridleys. The turtles are known to exhibit a unique synchronised mass nesting behaviour called arribada, as part of which thousands of female turtles converge on beaches, mostly on the Odisha coast, to lay eggs.
Tripathy says that the research so far had suggested that Olive Ridleys would come to the coasts of Odisha from Eastern Sri Lanka, stay six months, and return after the mass nesting.
“That this particular turtle nested on Ratnagiri’s shores suggests that all Olive Ridleys don’t come to Odisha or the eastern coast for mass nesting and that some travel towards the western coasts for nesting. This implies that we need to not only protect the east coasts (for the turtles) but also the west coasts,” he says, adding, “We can’t draw any conclusions based on the movement of one turtle. To confirm if its journey was accidental or incidental, we need to tag more turtles.”
Tagging of turtles
Experts say that the exact time it took the turtle to cover the distance and the route it took will remain in the realm of scientific conjectures since the turtle had a passive flipper tag and not a satellite tag.
While flipper tags are usually made of titanium or inconel and have a series of digits on one side and the return address on the other (the ZSI’s details in the case of this turtle), satellite tags are radio transmitters attached to the turtle’s shell. While both tags are used to study the migratory pattens of turtles, satellite tags provide detailed information on the routes of each of the tagged turtles while flipper tags provide information only when the turtle is caught.
ZSI’s Tripathy says flipper tags are more commonly used since they are cost effective. “The use of satellite telemetry can help to generate more information like the exact path of travel, but the scope is very limited because of the high costs involved,” says Tripathy.
In Odisha, where the beaches attract thousands of nesting Olive Ridley turtles every year, flipper tagging was carried out between 2021 and 2023. In January, Maharashtra launched flipper tagging on Olive Ridley turtles along the Konkan coast, in association with the Dehradun-based WII. Officials of the forest department said at least 64 turtles that came to nest along the state’s coasts have been tagged so far. Olive Ridley turtles in the state are commonly found nesting on the beaches of Alibaug, Anjarle, Guhagar and other coasts of Ratnagiri.
Scientists say the discovery of Turtle 03233, which exhibited a ‘dual nesting’ strategy, has added to existing knowledge about the nesting patterns of Olive Ridleys. In contrast to the mass nesting behaviour the turtle exhibited when it was flipper tagged in Odisha, in Ratnagiri, when a team of kasav mitras – villagers who volunteer for the forest department to patrol the beach and ensure a safe habitat for Olive Ridley turtles — found Turtle 03233 on January 22, it was alone, nesting.
Kanchan Pawar, Deputy Forest Officer, Mangrove South Konkan of the Maharashtra Forest Department, says, “When the team discovered the metal rings, they called us. After the turtle had completed nesting, they sent us pictures of the flipper tag, which bore the name of the Zoological Survey of India. Then, as we checked further details, we discovered that it was the same turtle which had been tagged in Odisha.”
The team left the turtle alone as it completed the nesting process – laying the eggs and covering them up with sand. The turtle then walked back into the sea.
Will 03233 swim all the way back to Odisha, from where it launched its journey? “This year, nearly 1,000 tagged turtles returned to Rushikulya beach on Odisha’s Ganjam coast. So yes, we can track the turtle if it returns to the Odisha coast,” says ZSI’s Tripathy.
