Trap cameras have captured tiger images on two Sunderbans islands, which mark the end of land and open into the vast expanse of the Bay of Bengal.

A senior forest official requested that the islands not be named for the safety of the apex predators. The names could be a giveaway for poachers in an otherwise remote habitat, he said.

Of the two islands, the bigger is around 3km from the Kendo forest beat. The smaller one, which is around 4km farther, is literally the southernmost tip of Bengal. The Sunderbans in Bangladesh is around 17km away, said forest officials.

Trap cameras were placed across the Sunderbans in winter as part of the state’s annual tiger estimation exercise in the world’s largest mangrove habitat for the big cat.

“The smaller island is spread over around five square kilometre. We have recorded six tiger images from there. From the bigger one, we have recorded more,” said a forest official.

Multiple images do not necessarily mean multiple tigers. The images are being analysed now to estimate the population.

For two consecutive years now, tiger images have been recorded from the two islands, which are officially part of the Sundarban Tiger Reserve (STR). The presence of tigers on the two islands suggests that conservation efforts are bearing fruit, said foresters.

Reaching the smaller island is a challenge, even for foresters. The safest time to reach the island is when the water is still. “There is a two-hour window between the time when high tide ends and the water starts receding. Our boats sail to the smaller island during that window. Otherwise, the waves are too strong,” said an official.

Expert swimmers that they are, Bengal tigers make the currents their ally and move between the larger Kendo forest and the two islands, he said.

The trap cameras have also taken images of a leopard cat, wild boars and deer on the two islands. It points to a prey base for the tigers. A few years ago, some spotted deer were released into the islands by the forest department.

Rajendra Jakhar, field director of the STR, attributed the presence of tigers on the two islands to “extensive conservation efforts”.

“Even a few years ago, trawlers on fishing expeditions would anchor on the islands. They would enter the smaller island via a creek. The engines and propellers of the boats cause a lot of disturbance for the animals. The occupants would leave plastic and other waste on the islands,” he said.

The islands are part of the core forest area and are out of bounds for fishing.

“We have increased patrolling. Our boats visit the island every second day,” said Jakhar.

“We have caught fishermen venturing into the island and imposed fines. Now, human interference has been reduced significantly,” said Jakhar.

More than 1,400 cameras were placed at strategic locations across the STR and the South 24-Parganas forest division from November 20, 2024, to January 6, 2025, as part of the state’s tiger estimation exercise.

The annual exercise is conducted by the forest departments of the states that have tigers in the wild.

The national tiger census — a quadrennial exercise — is conducted by the National Tiger Conservation Authority, which functions under the Centre.

The final report of the last national count, “Status of Tigers 2022”, was released by the National Tiger Conservation Authority on July 29 (International Tiger Day), 2023. The exercise pegged the number of tigers in India at 3,682. The Sunderbans had 101.

In 2020-21, the state-level exercise pegged the number of tigers at 96 in the Sunderbans. After that, the state forest department stopped formally releasing the results of the annual count.

“The count is for internal analysis. The authoritative figures are only released by the NTCA. The main objective of this annual estimation is to gauge the impact of the tiger protection and habitat-management steps we have been taking,” said an official at Aranya Bhavan, the state forest department headquarters.

The images captured by the trap cameras are being analysed.

“The initial findings are encouraging. STR has four ranges. In at least three, the tiger count seems to have risen,” said a source.