Monday, 30th October 2017

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Scientist sees port threat to rare turtles

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  • Published 1.08.13

New Delhi, July 31: Olive Ridley turtle populations mass nesting on Odisha’s coast now appear stable after what seemed like alarming portents a decade ago, but new ports could pose fresh threats, a senior turtle biologist said today.

The increasing numbers of turtles inadvertently caught by fishing trawlers and found dead on Odisha’s beaches during the 1990s had led some scientists to suggest a sharp decline in the populations of Olive Ridley turtles was imminent.

But observations over the past decade indicate an increase in the number of sites for mass nesting on Odisha’s coasts and fishing-related mortality has not increased, said Kartik Shanker, a marine ecologist at the Indian Institute of Science, Bangalore.

“Their population seems to be more stable today than what it seemed to be 10 years ago, the turtles are still dying but this appears for now to be not threatening the population,” Shanker said, in a talk at the Nehru Memorial Museum and Library here on the campaign to study and protect the Olive Ridley turtles.

“But the threat to the turtles is increasing and the battle is even bigger,” said Shanker, who has spent more than a decade studying the biology of the Olive Ridley turtles.

Conservation scientists estimate that between 100,000 and 200,000 Olive Ridley turtles come up for mass synchronised nesting at various sites along India’s east coast each year. Among the largest mass nesting sites are Gahirmatha and Rushikulya in Odisha.

Through the 1990s, teams of marine biologists had documented the deaths of up to 10,000 turtles each year at sites along the beaches of Odisha, causing concern among sections of scientists and non-government conservation groups and turning marine turtles into what Shanker says were “flagships or icons of marine conservation”.

The conservation campaign has had some impact — the company that built the Dhamra Port, north of the Gahirmatha nesting sites, had consulted conservation groups and scientists, seeking suggestions to reduce the risk to turtles. “But the port was treated as a fait accompli,” Shanker said.

He cautioned that the loss of habitat through the construction of new ports or activities such as oil exploration continue to threaten the Olive Ridley turtles. Even bright lights on a beach can disorient hatchlings and make them stray away from water.

“We need to ask — do we need so many ports and at the exact sites picked (for them)?” he said. The establishment of a port at an alternative site might come at some cost but, he said, could reduce the risk to the turtles and their mass nesting grounds.

Studies by the Bombay Natural History Society (BNHS) suggest that plantations of Causarina species along sections of the beach on Sriharikota island in Andhra Pradesh may also interfere with mass nesting. Such plantations may also provide shelter to mammalian predators of turtles, BNHS researcher S. Sivakumar and his colleagues wrote two years ago in the Indian Ocean Turtle Newsletter.

“There’s no room at all for complacency,” said Akila Balu, a volunteer with the Students Sea Turtles Conservation Network (SSTCN), a non-government organisation based in Chennai. “It is distressing to see dead turtles on the beach.”

Along a 14km stretch of beach near Chennai earlier this year, Balu said, SSTCN members had spotted several hundreds of dead turtles. “The actual mortality must be much higher as it is estimated that only 10 per cent of the carcasses are washed up on the beaches.”