Sea Turtles of the Andaman and Nicobar Islands
By Adhith Swaminathan and Kartik Shanker
India’s Andaman and Nicobar Islands (ANI), located east of mainland India in the Andaman Sea, are biogeographically (though not politically) part of the Southeast Asian region, connected to both the Indo-Burma and Sundaland hotspots. The islands are home to four of the five species of sea turtles found in Indian waters and are the only location in India where green, hawksbill, leatherback, and olive ridley turtles all nest. The archipelago, in addition to having significant nesting beaches, also hosts foraging grounds in the surrounding coral reefs and seagrass meadows, which are critical habitats for hawksbill and green turtles.
An olive ridley dines on a sea tomato jellyfish (Crambione mastigophora) in the Kei Islands of Indonesia. © Tui de Roy/Princeton University Press
Satish Bhaskar (see “In Memoriam 2024”), a pioneer of sea turtle biology and conservation in India, first visited ANI in 1978 and over a span of nearly two decades carried out extensive surveys in the islands, which have since been followed by numerous research and conservation initiatives throughout the islands. The ANI Department of Environment and Forest actively monitors important olive ridley nesting beaches in the North and Middle Andaman Islands, where hatchery programs have been running for several decades. In 2014, a small mass nesting site was discovered at Cuthbert Bay on Middle Andaman Island, leading to the establishment of a permanent monitoring camp there.
ANI also hosts India’s best nesting beaches for leatherback, hawksbill, and green turtles. Leatherback nesting has been monitored for the past four decades through periodic surveys of remote nesting sites and, more recently, through long-term annual monitoring. Of the more than 500 islands in the archipelago, leatherbacks nest in consistently high numbers on just three islands: Little Andaman, Little Nicobar, and Great Nicobar Islands. With annual numbers of about 1,000 nests in the Nicobar group and 100–200 nests on Little Andaman Island, these are the most significant nesting grounds for leatherback turtles in the northeastern Indian Ocean.
Following the 2004 Indian Ocean tsunami and earthquake, nesting on Little Andaman Island has remained stable. Beaches in the Nicobar Islands now witness nesting comparable to the pre-tsunami period, including on some beaches that were completely destroyed and have since formed again. Leatherbacks that originate in ANI migrate to foraging grounds in the Indian Ocean, as far east as Western Australia and as far west as Mozambique and Madagascar (see map “Sea Turtle Satelite Telemetry in Southeast Asia”). Demonstrating their resilience to natural calamities like the tsunami of 2004, those leatherbacks have continued to return to their ANI nesting and foraging grounds year after year.
Author Affiliation
Adhith Swaminathan, Dakshin Foundation, Bangalore, India
Kartik Shanker, Indian Institute of Science and Dakshin Foundation, Bangalore, India
This article originally appeared in SWOT Report, vol. 19 (2024). Download this article as a PDF.