1) Suganthi Devadason Marine Research Institute, 44-Beach Road, Tuticorin-628 001.
2) Wildlife Warden, Gulf of Mannar Marine National Park, Ramanathapuram.
The Gulf of Mannar Marine Biosphere Reserve, established in 1989, is located in Tamil Nadu on the southeast coast of India between 8º45’N and 9º25’N and 78º05’E and 79º30’E and harbours marine biodiversity of global significance. It is unique and renowned for its coral reef, sea grass and seaweed ecosystems. All five species of sea turtles (green, olive ridley, hawksbill, loggerhead and leatherback turtles) found in Indian waters have been reported along the Tamil Nadu coast. The rich coral reef and sea grass areas in the Gulf of Mannar form a good foraging ground for sea turtles and hence all the five species are reported to frequent this area.
The Gulf of Mannar coast was known for sea turtle trade in the 1960s. Targeted sea turtle fishing was carried out in this area during that period. Green turtles formed the majority of the catch and its blood has been considered as an elixir in the Tuticorin area (Rajagopalan, 1984). The turtle meat is believed to cure piles though no authentic scientific proof exists (Murugan, 2003). Death or injury due to turtle poisoning has also been reported along the Tuticorin coast (Silas and Bastian Fernando, 1984).
After the inclusion of all five species of sea turtles in Schedule I of the Indian Wild Life (Protection) Act 1972, exploitation was reduced to a great extent. The Gulf of Mannar region, including the islands, was also reported to be a good turtle nesting ground earlier (Chacko, 1942; CMFRI, 1977; Bastian Fernando, 1983). However, in recent years, nesting intensity has reduced substantially (Bhupathy and Saravanan, 2001) owing to many factors especially habitat degradation/disturbance, increased fishing pressure, incidental catch, exploitation for meat, egg collection, etc. Incidental catch is reported to be high on the east coast of India during the breeding season from October to February. The stranding or landings of sea turtles have been sporadically reported in the Gulf of Mannar area (Kasinathan, 1988; Krishna Pillai and Kasinathan, 1989; Ganapathy, 1994; Krishna Pillai et al., 1995; Krishna Pillai, 1998).
Four sea turtles were rescued on 23.07.2003 from an illegal trader by the officials of the Gulf of Mannar Marine National Park based on the information from police and released into the sea on 24.07.2003. After the rescue, the sea turtles were handed over to Suganthi Devadason Marine Research Institute (SDMRI) for identification and further study. The turtles were identified as green turtles, Chelonia mydas (one male and three females). Owing to rough handling of the animals, bloody scratches were observed on the carapace. Otherwise, all the turtles were in good condition. There were no other visible external injuries. No tags were found. The Curved Carapace Length (CCL) and Curved Carapace Width (CCW) of the turtles were measured and weight was taken (Table 1). The male turtle was the biggest among the four and weighed 83.5 kg. The turtles were maintained in SDMRI’s shore laboratory in the Tuticorin harbour area until 24.07.2003 midnight and after the completion of judicial formalities, the turtles were safely released into the sea. The turtles were said to be from incidental catch and no proper information is available on the exact location of the catch.
Table 1: Morphometrics of the rescued turtles
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Bhupathy, S. & S. Saravanan. 2001. A report on the status of sea turtles along the Tamil Nadu coast. In: Proceedings of the national workshop for the development of a national sea turtle conservation action plan, Bhubaneshwar, Orissa (Eds. K. Shanker & B.C. Choudhury), pp. 70 -73. GOI-UNDP Sea Turtle Project. Wildlife Institute of India, Dehradun, India.
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CMFRI, 1977. Report on the survey of the islands of Gulf of Mannar for the setting up of a Marine National Park.
Fernando, A.B. 1983. Nesting site and hatching of the hawksbill turtle along Tirunelveli coast of Tamil Nadu. Marine Fisheries Information Service T & E Series 50: 33-34.
Ganapathy, A. 1994. On a hawksbill turtle washed ashore near Thondi along Palk Bay coast in Tamil Nadu. Marine Fisheries Information Service T & E Series 133: 19.
Kasinathan, C. 1988. Olive ridleys landed at Pamban reported. Marine Fisheries Information Service T & E Series 84: 10.
Krishna Pillai, S. 1998. On the landing of an olive ridley turtle at Kanyakumari, Tamil Nadu and updated record of incidental catches of sea turtles in India. Marine Fisheries Information Service T & E Series 157: 17-20.
Krishna Pillai, S. & C. Kasinathan. 1989. On two species of marine turtles caught off Dhanushkodi, Gulf of Mannar. Marine Fisheries Information Service T & E Series 102: 17-18.
Krishna Pillai, S., M. Badrudeen & M. Bose. 1995. On a leatherback Dermochelys coriacea landed at Rameswaram. Marine Fisheries Information Service T & E Series140: 11.
Murugan, A. 2003. Status of Sea Turtles in India with emphasis on Andaman and Nicobar Islands. In: Proceedings of the 3rd Workshop of SEASTAR 2000: 63-70.
Rajagopalan, M. 1984. Value of sea turtles to India. In: Proceedings of the Workshop on Sea Turtle Conservation (ed. E.G.. Silas), pp 49-58. Central Marine Fisheries Research Institute Special Publication 18.
Silas, E.G. & A. Bastian Fernando. 1984. Turtle poisoning. Bulletin of the Central Marine Fisheries Research Institute 35: 62-70.
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