National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Government of India, Chennai, India
There are five species of sea turtles reported from Indian waters, the olive ridley, green, leatherback, loggerhead, and hawksbill (Kar and Bhaskar, 1982; Bhupathy & Saravanan, 2002). In the past two decades, reports from within both the Indian and international media have indicated an increase in sea turtle mortality along several coastal stretches of the east coast of India due to anthropogenic activities, including fishing, movement of shipping vessels, disposal of municipal waste and coastal armouring structures (Sachithanandam et al., 2015). India’s Coastal Regulation Zone (CRZ) Notification, 2011, under the Environment (Protection) Act, 1986, declared all turtle nesting areas of the Indian coastline as Ecologically Sensitive Areas (ESAs) and regulated human activities within them. In Odisha, olive ridley turtles exhibit synchronous mass nesting, known as arribadas. This species is listed as Endangered under in Schedule 1 of the Indian Wildlife (Protection) Act, 1972. Further, the Hon’ble Supreme Court of India (2003) recommended banning of trawlers within 20 km of the three mass nesting beaches during the November to May nesting period in Odisha.
To quantify turtle mortality along the Tamil Nadu coast, which is both nesting habitat for olive ridley turtles and part of the migratory corridor for olive ridleys that nest in Odisha, field work was conducted from December 2013 to July 2014. Using a hand held Trimble GPS, we recorded 96 and 134 carcasses of olive ridley turtles along the Chennai coast (between Foreshore Estate and Napier Bridge) and Nagapattinam coast (between Nagapattinam Port and Nagore) respectively. A questionnaire was also used to survey local fishing communities for their perspective on the capture rate of sea turtles. From the responses, we inferred that the primary cause (80%) of turtle mortality during the period were fishing activities including trawling, setting of gill nets, and offshore long line fishing, and factors such as pollution and predators resulted in 20% of turtle mortalities. Nearly 85% of turtle mortality occurred between December and March, and most during the November to May breeding period. Close to 60% of fishers reported that turtles became entangled in their nets during fishing activities, 45% indicated that they were not aware of the importance of sea turtles, and 30% stated that they were unaware of the 2011 CRZ notification.
Fishing is the main livelihood for coastal people in this region, and gill nets, trawlers, nylon dip net, cotton drag nets, cotton shore seines, and long lines are all in operation. Kasimedu Harbour and Chennai Port are located on the northern side of the Chennai study site, and the sea is always busy with passage of cargo vessels, fishing boats, and passenger ships. The Tamil Nadu Marine Fisheries Census of 2010 indicated there are 2,800 trawl boats and 3,000 non-mechanised boats operated at Kasimedu, and 1,465 mechanised and 4,129 non-mechanised crafts in Nagapattinam district, with 32,652 units of fishing gear (Sachithanandam et al., 2015).
To further protect the sea turtles in Tamil Nadu, the following are recommended:
Bhupathy, S & S. Saravanan. 2002. Status of sea turtles along the Tamil Nadu coast, India. Kachhapa 7: 7-13
IUCN. 2010. IUCN Red List of threatened Species. Version 2010.1. http://www.iucnredlist.org. Accessed on 11th April 2010.
Kar, C.S. & S. Bhaskar. 1982. Status of sea turtle in the Eastern Indian Ocean. In: Biology and conservation of sea turtles. Pp: 365-372. K.A. Bjorndal (Ed.) Smithsonian Institution press, Washington, D.C
Sachithanandam, V., T. Mageswaran, R. Sridhar, T. Arumugam & R. Ramesh. 2015. Marine turtle mortalities along the Tamil Nadu coast of India and the need for turtle-friendly fisheries. Biodiversity 16: 8-14.
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