Northern River Terrapins Released in the Sunderbans

by Shailendra Singh 

The northern river terrapin (Batagur baska) is one of the world's most endangered turtles with fewer than 50 adults at four captive locations and very little evidence of surviving wild specimens. The Turtle Survival Alliance (TSA), in partnership with the West Bangal Forest Department, has been managing a conservation breeding program for this species within the Sunderbans region of India. The Sunderbans is the largest mangrove forest in the world, located along the border between India and Bangladesh. The area is best known for its tigers (Panthera tigris) and saltwater crocodiles (Crocodylus porosus).

To date the TSA team in India has headstarted 145 hatchlings at the conservation breeding facility at the forest ranger station within Sunderbans National Park. This year, with the support of of People's Trust for Endangered Species (PTES) and Ocean Park Hongkong Conservation Fund (OPHKCF), the team reintroduced (released) ten (three males and seven females) juveniles from our facility to learn more about their survival and dispersal, as well as habitat use. Turtle were fitted with acoustic transmitters prior to release that would allow them to be tracked by biologists. The animals were released into a soft-release pen (contained area of natural habitat that allow the animals to acclimate prior to being fully released to the wild) that was constructed on a 300 meter long secondary channel using 800 pieces of bamboo and 50 fishing nets. Turtles were held in the soft-release pen for about a month where they were observed and tracked using directional hydrophones and man-track units provided by Sonotronics. The turtles have since been released, but have not yet been tracked due to the vast, rugged terrain that bring with it many logistical challenges and the risk of tiger attack! However, a two-member research team has continuously been monitoring the area near the release site and plan to increase the search radius, using small motorboats. 

Information on the survival, dispersal and habitat use for this species that could be provided by this long-term study will help the team in India prepare a plan to scale up reintroduction efforts in the future. The release team included RK Mahtolia, Nilanjan Mallik, Shailendra Singh, Niladri Dasgupta and Saurav Gawan. The project was carried out under the guidance of Dr Pradeep Vyas, PCCF Wildlife West Bengal.