Expressing doubt whether the Sunderbans, which according to the last census in 2001 had 274 tigers, the NGO — Nature, Environment and Wildlife Society (NEWS) — in a letter to the National Tiger Conservation Authority (NTCA) said there should be a scientific study to ascertain the number of the big cats and to determine the prey base.

Claiming that the release of the deer was being done in an unscientific manner, NEWS secretary Biswajit Roy Chowdhury said, “Determination of the root cause for decline in prey base through a scientific basis is the need of the hour. How is such a step justified when looked at in the long-term?”

But the Field Director of Sunderbans Tiger Reserve (STR) Subrat Mukhjeree defended the government’s decision saying it was done after calls from different quarters that the big cats were straying into human habitation because of a shortage in prey base in the forests.

The state forest department also said that it was done in consultation with the state wildlife advisory board, the apex body which included representatives of wildlife NGOs.

“Nobody raised any objection when the decision was taken to release deer in the Sunderbans. In fact, deer were also released in Buxa tiger reserve and Jaldapara Wildlife sanctuary which has tigers,” Pradeep Vyas, Director Sunderban Biosphere Reserve told PTI.

Admitting that the prey base might not be uniform in all the islands in the Sunderbans as it depended on the vegetation, Vyas said shortage of prey base could not be the only reason for tigers straying. There were other factors for it as well, he added.

The NEWS claimed that 63 deer would be totally insufficient for the tigers in the reserve. Roy Chowdhury asked whether the forest department planned to release a second lot of deer and continue the practice in the Sunderbans.