Endangered turtles play fast and loose with borders

Animals in nature know no international boundaries and this has come as some sort of a surprise and challenge to experts and forest officials who installed GPS transmitters on Nothern River Terrapin in Indian Sundarbans.

 In just six weeks after the release, at least three of the ten individuals of the critically endangered Northern River Terrapin ( Batagur baska) have travelled hundreds of kilometers and are now in Bangladesh.

Shailendra Singh, director of Turtle Survival Alliance India, who played an important role in the conservation and release of the turtles, said that the animals have traversed hundreds of kilometers and in the case of one turtle that is in Bangladesh at present, the dispersal has been about 400 km.

“There are three turtles that have entered Bangladesh. In the case of maximum dispersal, the animal descended from the release site in Indian Sundarbans, crossed the sea and Bangladesh Sundarbans, and is now on its fringe area,” Dr. Singh said.

 Of the three turtles in Bangladesh, one was caught by fishermen in Bangladesh who removed the transmitter from the animal.

“Fortunately, there was a telephone number on the transmitter and somehow the fishermen contacted the TSA office and we approached officials of the Sundarban Tiger Reserve. We are trying to bring the turtle back to India,” Dr. Singh said.

 Of the ten animals released with the transmitter, signals are coming from six, four from India, and two from Bangladesh. Experts have pointed out that five of the animals have descended down from the site of release in Sundarbans and moved south.

Justin Jones, Deputy Director of the Sundarbans Tiger Reserve said that the turtle has been rescued by the Bangladesh Forest Department.

“We are trying to bring back the animal but at present the animal is at a facility under Khulna Forest Department. Bangladesh also has a facility for  Batagur Baska, and the animal which is injured is at the facility,” Mr. Jones said.

Highlighting the need for the release of the critically endangered turtles, the official of Sundarban Tiger Reserve said the objective of the initiative was to ascertain the habitat, breeding pattern and the movement of the species.

The population of the Nothern River Terrapin, a freshwater turtle, had reached critical limits about 15 years ago when experts and forest officials were not sure about any surviving population of the freshwater turtles  in the Sundarbans.

In 2008, a joint exploration of swamps mangroves and tidal creeks by the Turtle Survival Alliance (TSA) and Sundarban Tiger Reserve (STR) located a cohort of eight males, three females, and one juvenile in a pond at the Sajnekhali Interpretation Center. In the past 14 years, the conservation breeding of the species, categorised as critically endangered by IUCN Red List, has been a success with almost 12 adults and close to 370 juveniles of the species.  

The conservation breeding programme of the species came a full circle on January 19, 2022, when ten sub-adults  Batagur Baska reared for over nine years, were reintroduced into the wild by the experts of TSA and STR.

With the emergence of data on the movement of the species, experts and forest officials are excited about the possibility of discovering new details about the species.

TSA India, Director Shailendra Singh said that the batteries fitted with the GPS transmitter can function for 18 months and it will be interesting to watch the movement of the turtles in the monsoons.