By Shailendra Singh & Sushmita Kar, 11th June 2024
Softshell turtles, all members of the reptile family Trionychidae, comprise approximately 30 species that mostly live in freshwater habitats across temperate and tropical regions of Africa, Asia and North America. Their name points to the nature of their shells, which lack the hard, horny epidermal scutes characteristic of most turtles, making them leathery and pliable. They may not look like fierce hunters, but softshell turtles are primarily carnivores that ambush their prey such as fish, worms, crustaceans and even waterfowl.
The black softshell turtle Nilssonia nigricans occurs in India and Bangladesh, but its fate has been hanging in the balance for decades. The species was traditionally hunted for its meat and is threatened by overexploitation and fisheries bycatch. Endemic to the Brahmaputra basin, this turtle was thought to be extinct in the wild until recent sightings revealed its presence in the Brahmaputra River and in a few temple ponds in east and north-east India. In 2022, some were even discovered in a wetland in southern Nepal, renewing hopes for the conservation of this Critically Endangered species.
An adult Black softshell turtle at Nagshankar temple in Assam, India. Photo: Arunima Singh.
The species is considered sacred in Hinduism, and for many years temple-goers have been donating wild individuals to temples for religious purposes, inadvertently leading to the creation of semi-captive populations. These isolated populations have been maintained in temple ponds in north-east India, mainly in Assam where such ponds hold a number of threatened turtle species. But temple ponds are not ideal environments for the turtles, and without protection, the eggs and nests are at risk of drying out or being lost to depredation by feral dogs and mongooses. To prevent this, the project team from the TSA Foundation India has been assisting some temple ponds with husbandry improvements, nest protection and rear-and-release programmes since 2018. In the past few years, the team have stepped up our conservation actions for the species and begun to release hatchlings of these semi-captive individuals to the wild, in efforts to recover the wild population of this fascinating species.
Pilot release of Black softshell turtle hatchlings along Brahmaputra at Biswanath Wildlife Division, Kaziranga Tiger Reserve in Assam, India. Photo: Jayanta Bhuyan.
In 2023, we chose two new release sites that would allow the turtles to acclimatize over the winter before dispersing into the mainstream as the river floods during the monsoon. Then, over three occasions, we released a total of 150 healthy black softshell turtle hatchlings into the river at these two locations. The hatchlings were approximately 5 months old and came from eggs collected from nests protected at Nagshankar temple in Assam. To get them ready for release, newly emerged hatchlings were fed live fish fingerlings, maintained in a heated indoor environment and regularly moved into the sun for basking.
At the same time, we also provided terracotta model turtles for temple visitors to offer to Lord Shiva in lieu of live turtles. Our aim here was to support local beliefs and religious practices, while also providing income for local vendors and minimizing the collection of wild turtles. There were some exotic predatory fish in the Nagshankar pond, so to keep the turtle hatchlings safe, on a couple of occasions we safely removed these and replaced them with native fishes, as it is forbidden to harm any live individual (e.g. fish, turtles, birds) that are being kept within the temple premises.
To maximize the impact of our project and ensure it would benefit local people as well as the turtles, we also carried out education programmes at riverside schools and worked with the local fishing community near the key release sites. At Gamirighat and Bishwanathghat, the TSA project team have been working with 15 female members of the fishing community (a group we have named Kaso Sakhi–’the friends of turtles’) on skill development trainings, empowering the women through weaving and selling traditional turtle-motif scarves (Gamocha in Assamese). We have partnered with Pashoo-Pakshee, an online store supporting wildlife and communities, as well as a few other outlets to sell the products made by the women, and we are working with the Handloom Department of the Government of Assam to help us to expand this model in to other nearby fishing villages, by providing subsidized raw materials and selling the products at a larger scale.
Left: An adult Black softshell turtle at Nagshankar temple. Right: Nest protection at Nagshankar temple by the project team. Photos: Sushmita Kar (left) & Bidyut Bikash Chamuah (right).
Moving forward, we would like to set up a long-term monitoring programme at our rearing facility, so that we are better able to gauge the project’s success. Currently, around 35 hatchlings from 2023 are being retained in the semi-captive facility until their weight reaches 1 kg, at which point they will be fitted with acoustic telemetry devices prior to release. This technology will allow us to monitor their post-release survival and dispersal.
The project team is also trying to procure some large semi-natural fishing ponds that we can raise juvenile turtles in, to replace the smaller cement tanks currently used at our facility and at Assam Zoo. Soft-shell turtles grow faster and often become aggressive toward weaker individuals when kept in high density. These larger earthen ponds would provide a muddy bottom and edges that would thermoregulate the tank and enhance our capacity to rear more juveniles, and would be continuously stocked with native fish fingerlings. Once we are ready to release the turtles in 1-2 years, we want to involve local fishermen, who can keep any additional fish stock and keep an eye out for the turtles. Setting up this ‘fish-turtle’ rearing cooperative in the area has been challenging so far, but an integrated model like this could contribute to the local economy (through selling left-over fish) and build confidence between community members and the turtle project.
Left: Pilot release of Black softshell turtle hatchlings at Biswanath Wildlife Division, Kaziranga Tiger Reserve. Right: Measuring a hatchling in Biswanath, Assam. Photos: Jayanta Bhuyan (left) & Monalisha Basistha (right).
This collaborative effort between conservation agencies, religious organizations, government bodies and local fishing communities is helping to bring the black softshell turtle back from the brink of extinction. We are working to gradually expand this model to other religious places in north-east India, as well as in the state of West Bengal and in Bangladesh. This project was supported by Disney Conservation Fund, Prince Bernard Nature Conservation Fund, the Assam Forest Department and Turtle Survival Alliance, USA.
The Conservation News item ‘Rewilding of black softshell turtles in Brahmaputra landscape, India’ is available open access in Oryx—The International Journal of Conservation.
