Leatherback turtles in the Andamans: Highest number of turtle nests in a decade found this year

Researchers and the Andaman and Nicobar Forest Department have recorded the maximum number of turtle nests for a single season in the Little Andaman Islands this year. With 302 nests identified, this is the highest number recorded since turtle egg-monitoring began in the islands in 2010.Nesting season for the leatherback turtle in the islands begins in December and goes on till March every year."This indicates that leatherback nesting on beaches of the Little Andaman Island has recovered substantially after the 2004 tsunami. It now seems stable with some fluctuations," says Adhith Swaminathan, senior research assistant, Dakshin Foundation, who has been working on the islands since the monitoring project began in 2010.[caption id="attachment_6602341" align="alignnone" width="1024"]

Sea turtles hatching and heading seawards.[/caption]An average of 1,000 leatherback nests is found across the Andaman and Nicobar islands over the years, making this a significant nesting population in the South Asian region — and the only one in India.The leatherback is the largest sea turtle in the world and is considered a vulnerable species by the International Union for Conservation of Nature (IUCN). Muralidharan M, field director, Dakshin foundation said, "Little Nicobar Island and Great Nicobar Island constitutes 94 percent of the total nests found in the Nicobar region. A rapid survey of Little and Great Nicobar Island was carried out to assess if the high nesting observed in Little Andaman extends to the Nicobar region as well."Over 300 leatherback nests found in the nesting beaches of Little Andaman, where an average of about 150 nests are usually found every year. He added, "This is the highest number of nests recorded for turtles since the initiation of our monitoring camp in 2010. Existing literature on sea turtle monitoring programs around the world indicates that these fluctuations in nesting numbers may arise in response to inter-annual variations in breeding behaviour due to climate change."

Relatives of modern leatherback turtles have existed in some form since the first true sea turtles evolved over 110 million years ago during the Cretaceous period. They mate at sea and the males never leave the water once they enter it as hatchlings, unlike females, which come back to nest on land.Leatherback turtles are among the deepest-diving marine animals and have been recorded diving to depths of over 1000 metres. They are also the fastest moving reptiles and can swim at speeds of up to 35 km per hour.Major causes for their endangered status include loss of nesting beaches due to developmental plans, sea erosion and plastic pollution of the oceans. Researchers are certain that these turtles mistake plastic for jellyfish. An estimated one-third of all adults of the species have ingested plastic at some point or the other in their lifetimes.

"Though we have a general understanding on the nesting population in the Andaman and Nicobar region, it is important that a continuous long-term annual monitoring program is carried out to obtain reliable data on leatherbacks at key nesting sites and index beaches such as South and West Bay, Little Andaman," Muralidharan says. "Since Great Nicobar Island receives the highest nesting in the region, we are hoping to extend our long term monitoring efforts to study nesting trends, nest site fidelity, population recruitment and post-nesting migratory routes of the turtles nesting in Nicobar as well."