Nesting species: olive ridley
Tamil Nadu and Puducherry together account for 1,076 km of India’s eastern coastline (with 980 km of this stretch belonging to Tamil Nadu). Tamil Nadu is bound by the Bay of Bengal in the east, the Gulf of Mannar and Palk Strait in the southeast and the Indian Ocean in the south. All the five species of marine turtles found in Indian waters–olive ridley turtles, green turtles, leatherback turtles, loggerhead and hawksbill turtles–are reported in these waters. This coast forms a part of the migratory corridor for olive ridleys that mass-nest in Orissa. About 530 km of the coastline has sandy beaches and is assumed to be suitable for turtle nesting. However, a majority of the beaches between Kanniyakumari and Tiruchendur have sandy beaches and are highly impacted by sand mining.
The only species which nests along this coast is the olive ridley turtle, and the total number of nests is estimated to be about 2,000 to 3,000 per year. Green turtles and olive ridleys forage in the Gulf of Mannar and Palk Bay waters. There is considerable concern about nesting habitats and feeding areas in Tamil Nadu as an increasing number of dead turtles are found every year along this coast. During a survey conducted in 2000-01, 462 carcasses were counted and a large number observed along Nagapattinam coast. This high rate of mortality is attributed to incidental catch in fishing gear and exploitation of turtles for food.
The oldest known references to marine turtles come from this region, from a poem of the Tamil Sangam literature (c. 400 AD) in which the egg-laying of marine turtles has been described. Research and conservation along the coast of India was initiated by the Madras Snake Park Trust (MSPT) in 1974, marking one of the first marine turtle programmes in India. Currently several government and non-government organisations are involved in marine turtle conservation on the Tamil Nadu coast.
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Like in other parts of India, marine turtles along this coast face a variety of threats. In some parts along the southern coast of Tamil Nadu, they are regularly exploited for food. Incidental catch of turtles has been reported as a major cause of turtle mortality along this coast. A large number of current and proposed development projects on the coast and in nearshore waters pose serious threats. Modernisation of fishing practices is another major concern. For instance, the shift from traditional fishing using catamarans to trawlers, especially in the Gulf of Mannar is a potential threat to the survival of marine turtles and other marine fauna that share these waters.
In Puducherry, beach erosion is one of the major threats to nesting habitats of turtles. The government of Puducherry has constructed embankments along the coastline including groynes and seawalls, particularly along the urban stretches to prevent further erosion.
Conservation of sea turtles on this coast (primarily concentrated around Chennai) was initiated by Romulus Whitaker in 1973. Subsequently, hatcheries were maintained by the Central Marine Fisheries Research Institute and the Tamil Nadu Forest Department. The Students’ Sea Turtle Conservation Network (SSTCN)–a voluntary organisation run primarily by students–initiated a sea turtle conservation programme in 1988 and continues to carry out its activities along the Chennai coast, including maintaining a hatchery and education and awareness for school and college students. Over the past few years, the Trust for Environmental Education (TREE) has initiated in situ conservation programmes with fishing youth from several villages along the northern Tamil Nadu and Puducherry coast.
Both Tamil Nadu and Pondicherry have notified under their respective Marine Fishing Regulation Acts the use of TED by shrimp trawlers in the waters under their jurisdiction; however the implementation of this regulation has been relatively poor.
Source: Bhupathy, S. & S. Saravanan. 2006. Marine turtles of Tamil Nadu. In: Marine turtles of the Indian subcontinent(Eds. Shanker, K. & B.C. Choudhury). Pp. 58–67. Universities Press (India) Private Ltd.
Sanjeeva Raj, P.J. 1958. Egg-laying habits of sea turtles described in Tamil Sangam literature. J. of the Bombay Nat. Hist. Soc. 55: 361–362.
Valliappan, S. & R. Whitaker. 1975. Olive ridleys on the Coromandel coast of India. Herpetological Review 6(2): 42–43.
Whitaker, R. 1977. A note on sea turtles of Madras. Indian Forester 103(11): 733–734.
Agastheesapillai, A. & R. Thiagarajan. 1979. Biology of the green turtle Chelonia mydas (Linnaeus) in the Gulf of Mannar and Palk Bay. J. of the Marine Biol. Assoc. of India 21 (1&2): 45–60.
Bhaskar, S. 1981. Sea turtle survey of southern Tamil Nadu. Report to the WWF-India.
Kar, C.S. & S. Bhaskar. 1982. Status of sea turtles in the eastern Indian ocean. In: Biology and conservation of sea turtles (Ed. Bjorndal, K.). Pp. 365–372. Smithsonian Institution Press: Washington D.C.
Shanker, K. 1995. Conservation of sea turtles on the Madras coast. Marine Turtle Newsletter 64: 3–6.
Banugopan, K. & P. Davidar. 1999. Status of sea turtles along the Pondicherry coast, India. Hamadryad 24: 43.
Bhupathy, S. & S. Saravanan. 2002. Status of sea turtles along the Tamil Nadu Coast. Kachhapa 7: 7–13.
Shanker, K. 2003. Thirty years of sea turtle conservation on the Madras coast: A review Kachhapa 8: 16–19.
Bhupathy, S. & S. Saravanan. 2006. Marine turtles of Tamil Nadu. In: Marine turtles of the Indian subcontinent (Eds. Shanker, K. & B.C. Choudhury). Pp. 58–67. Universities Press (India) Private Ltd.
Bhupathy, S. 2007. Monitoring of marine turtles along the Kerala and Tamil Nadu coasts. Indian Ocean Turtle Newsletter 5: 1–9.
Madras Crocodile Bank Trust (MCBT) / Centre for Herpetology, Mamallapuram
Trust for Environmental Education (TREE), Chennai
Students’ Sea Turtle Conservation Network (SSTCN), Chennai
Salim Ali Centre for Ornithology and Natural History (SACON), Coimbatore