Central Marine Fisheries Research Institute, Mandapam Regional Centre, Tamil Nadu India
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The Gulf of Mannar Biosphere Reserve was started in 1989 jointly by the Government of India and the state of Tamilnadu. It has an area of about 10,500 km2 between 8°45’N and 9°25’N and 78°05’E and 79°30’E about 170 nautical miles including the 21 islands in the gulf. Of the seven species of sea turtles in the world, four have been reported nesting on the Gulf of Mannar coast of Tamil Nadu (Kar & Bhaskar, 1982): the green (Chelonia mydas, local name: Paer aamai), olive ridley (Lepidochelys olivacea, local name: Yeth aamai), leatherback (Dermochelys coriacea, local name: Ezhuvari aamai) and hawksbill (Eretmochelys imbricata, local name: Kilimooku amai) sea turtles.
The nesting season for olive ridley turtles along the Gulf of Mannar coast of Tamil Nadu occurs from December to April (Bhupathy & Saravanan, 2006). The operation of shore seines may result in the accidental catch of turtles, and capture occurs more frequently from October to February (Thirumalaiselvan, pers.ob.). The accidental catch of sea turtles in the Gulf of Mannar is mostly unreported or unnoticed. Some reported cases include olive ridley turtles at Pamban (Kasinathan, 1988) and Dhanushkodi (Krishna & Kasinathan, 1989), and leatherback turtles at Dhanushkodi (Krishna & Kasinathan, 1989), Rameswaram (Krishna et al., 1995) and Mandapam (Rao et al., 1989).
During our routine field observations on 28th January 2017, we observed a shore seine operation by the traditional fishers of Dhanuskodi. The shore seine was operated by 35 to 40 local fishers. When the shore seine drag ended, we found two sea turtles had been accidentally caught in the net with the fish catch. The turtles were identified as one male and one female (sex based on plastron shape and proximity of the cloaca to the plastron) olive ridley turtle; morphometric measurements are given in Table 1. The turtles were thoroughly examined and showed no sign of injury. The local fishers initially declined to release the turtles into the sea due to their lack of awareness about the turtles. However, we explained about the importance of turtles to the marine ecosystem and, with their assistance, we released them back into the sea. We speculate that the turtles may have been in the area for breeding, but the female showed no signs of mating damage (bite marks on neck or claw marks on shoulders or carapace).
Table 1: Carapace dimensions and weight of olive ridley turtles rescued from a shore seine net in Dhanuskodi, Tamil Nadu.
|
Sex |
CCL (cm) | CCW (cm) | Weight (kg) |
|
Male |
61 |
58 |
38 |
| Female | 65 | 61 |
45 |
The authors acknowledge the support and encouragement of A Gopalakrishnan, Director, CMFRI, Kochi and A. K Abdul Nazar, Scientist in-Charge of Mandapam Regional Centre of CMFRI.
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