Once a delicacy for British colonialists and native Bengalis, the critically endangered northern river terrapin in Sundarbans was on verge of extinction with only 100 mature adult turtles left in the wild. Conservation efforts are now giving them hope.
The Batagur Baska, also known as the northern river terrapin, is an elusive and critically endangered turtle species native to Southeast Asia, particularly the Sundarbans mangrove delta in India and Bangladesh.
Classified as “critically endangered” by the International Union for Conservation of Nature (IUCN) in 2018, the Batagur baska’s wild population is estimated to be only about 100 mature adults. In stark contrast, the more famous Olive Ridley turtles, classified as “vulnerable” by IUCN, saw nearly 500,000 turn up to nest on the Rushikulya coast of Odisha in 2022.
The riverine turtles have largely remained out of the public eye, with tourists in the Sundarbans rarely ever catching a glimpse of them in the wild. However, due to sustained efforts by the West Bengal forest department and wildlife research institutes, there is now hope for this marine animal’s population to increase.
According to 19th-century British zoologist Edward Blyth, the Batagur baska was once considered a culinary delicacy by colonial rulers and influential Bengalis, leading to excessive poaching and rampant turtle egg collection that decimated their population.
In 2000, the department of posts released a stamp of the Batagur baska at the National Philatelic Exhibition in Bhubaneswar to raise awareness about this fast-disappearing species.
In 2008, five female and seven male Batagur baska turtles were discovered in a pond on Sajnekhali island of Sundarbans. According to West Bengal’s deputy forest director Jones Justin, this “founder batch” initiated conservation efforts.
In 2012, the batch successfully produced hatchlings for the first time.
“This gave us the conviction that they could be bred in captivity,” Justin said.
As of 2024, 430 Batagur baska turtles are being bred in captivity across seven “assurance colonies” in the Sundarbans, including Sajnekhali, Netidhopani and Harikhali. The forest department aims to breed the turtles in captivity first and then release them into the wild. However, a critical question remains: does a natural habitat still exist for the northern river terrapin to thrive and reproduce independently?
Amirtha Balan, a wildlife researcher with the Wildlife Institute of India and project associate with the West Bengal forest department since 2022, said: “The Batagur baska is the only estuarine turtle that nests on sandy beaches and prefers mangrove areas. Alarmingly, their numbers have been reducing more drastically than any other species living in that area.”
Habitat loss, rising water levels and increasing salinity in the Sundarbans delta pose significant threats to their survival. In 1998, Batagur baska eggs were found on Mechua island, whose sandy banks have since been steadily submerging. The rising water levels have caused multiple islands to erode and partially submerge, further endangering these turtles’ habitat.
In 2021, the state forest department achieved noteworthy success with artificial incubation, yielding a 95 percent maturity rate for eggs laid by the first hatchling batch.
“Our plan is to release close to 500 of these animals in the wild, every year, by 2030,” Justin shared.
In 2022, a group of 10 Batagur baska turtles were released into the Sundarbans delta by the forest department and Turtle Survival Alliance, an NGO.
“They were tracked for a year using satellite technology to ascertain their ideal weight for survival in the wild, as well as their preferred salinity and pH levels,” said Justin.
It was found that they preferred fresher waters, and increasing salinity levels due to natural as well as man-made factors are making survival more difficult. Rising temperatures due to global warming skew the sex ratio of hatchlings, with higher temperatures producing more females, complicating mating prospects.
Satellite tracking data has been instrumental in identifying threats to this critically endangered species and is being used to raise awareness among local fisherfolk in the Sundarbans regarding the conservation of the Batagur baska.
Often called “water vultures”, these riverine turtles play a crucial role in cleaning the estuarine ecosystem due to their omnivorous diet, which includes smaller animals and plants, often dead. Their presence is challenged by the adverse environmental factors specific to the Sundarbans delta, making conservation efforts urgent.
As these unique and rare Batagur baska turtles continue to fight against the odds, their journey underscores the vital importance of dedicated conservation efforts in preserving our planet’s biodiversity.
The lead image on top shows a Batagur baska, the only estuarine turtle that nests on sandy beaches and prefers mangrove areas. (Photo courtesy West Bengal forest department)
Sukanya Roy is a freelance journalist based out of Kolkata, and she believes in crafting impactful stories on the themes of gender, human rights, sexuality, environment, and the lives of denotified tribes and communities in India.
