Olive Ridleys of India Genetically different from other Olive Ridley turtles – via Herp Digest

By Ashis Senapati  |  New India Express News Service  | 3/24/18

File photo of a turtle fitted with satellite transmitter | Express

KENDRAPARA: There is a significant genetic difference between Olive Ridleys of India and the turtles of Costa Rica, Mexico, Australia and other countries. A large number of sea turtles which lay eggs in the world’s largest rookery at Gahiramatha Marine Sanctuary of Kendrapara district and Rushikulya river mouth in Ganjam every year are an isolated population who live in the Bay of Bengal. These turtles have no link with the ones of the Pacific Ocean and the Atlantic Ocean, said Dr Basudev Tripathy, noted biologist and Deputy Director of Zoological  Survey of India, Kolkata.

Dr Tripathy has been doing research on Olive Ridley sea turtles in Odisha for more than two decades.

  “Our research work on Olive Ridley turtles on Odisha coast also showed that the turtle population in the State is quite different from the ones which visit other mass nesting sites of Costa Rica, Mexico and Australia. It also demolished the myth that Olive Ridleys come from Australia, Costa Rica and other countries from the Pacific Ocean for laying eggs at Gahiramatha and Rushikulya, said Dr Tripathy.

 “In 2008, we had fitted Platform Transmitter Terminals (PTTs) on 30 Olive Ridleys at Gahiramatha, Devi and Rushikulya. Around 14 turtles with PTTs arrived at Gahiramatha marine sanctuary from Sri Lanka a few years back. This proves that the turtles move around the coast of Sri Lanka. Olive Ridleys migrate long distances between their feeding grounds in the deep sea of the Bay of Bengal and nesting sites in Odisha. It is a myth that the turtles come from the Pacific Ocean, he said.

In April 2001, the Forest department, Wildlife Institute of India (WII) and turtle biologist Jack Frazier of Smithsonian Institution had also fitted four turtles with PTTs at Devi beach and monitored their migratory routes online. The PTT-fitted turtles circled the waters and only one was seen migrating south towards Sri Lanka. Unfortunately, all four turtles stopped transmitting within two to four months either due to some technical problems or trawler-related mortality, the official said.

The Forest department, in collaboration with  WII, Dehradun had also fitted tags on the flippers of 35,000 turtles from 1996 to 1999 in Gahiramatha, Rushikulya and Devi river mouths. “In the past, we have also sighted many tagged turtles on the same beach where they were marked.  Finding some tagged turtles in Gahiramatha and Rushikulya proved that the females return to the same beach where they first laid eggs. It has been proved by turtle researchers that female turtles lay eggs where they were born decades back,” he informed. Recently, more than a million Olive Ridleys laid eggs at Gahiramatha and Rushikulya due to sincere efforts of turtle researchers, forest officials, locals and others, Dr Tripathy added.

Research Result

Around 14 turtles with PTTs arrived at Gahiramatha marine sanctuary from Sri Lanka a few years back

PTT-fitted turtles circled waters and only one was seen migrating south towards Sri Lanka

In April 2001, the Forest department, Wildlife Institute of India and turtle biologist Jack Frazier of Smithsonian Institution had also fitted four turtles with PTTs at Devi beach and monitored their migratory routes online.