It is poaching of a different kind.

While tigers have been killed in Sariska and other national parks, the famous Royal Bengal variety of the big cat in the Sunderbans faces dwindling prey base caused by poaching.

In the world's largest mangrove, the tiger is facing scarcity of food as poaching of its favourite prey, the spotted deer, has been on the rise in recent years.

Wildlife officials say if the trend continues, it would be difficult for the tiger to sustain itself on the available prey base in the 4000 sq km forests.

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If it fails to get its prey inside the forest, it would stray into villages in the vicinity and hunt for cattle or humans, which in turn could result in killing of the big cats by angry villagers, says Director of Sundarbans Biosphere Reserve, Atanu Raha.

"Yes, it is a cause for concern. There have been cases of poaching of spotted deer. We have begun a massive campaign to stop villagers from eating deer meat. If there is no ready market, the demand for meat would go down. But it is a tough task since the forests are a huge open resource with lakhs of people inhabiting its fringes," he says.

The reserve, which has 274 tigers (the last census was conducted in 2004), has only 150 forest staff to man its borders, Raha says.

He added that the number is dismally low to put either a check on poaching or take up conservation efforts.

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The 'conservation first' approach of the campaign involves making people aware of the evils of eating into the tiger's prey base and taking villagers into confidence by making them 'informers'.

"If herbivores flourish, so will the tigers," Raha says.

As far as tiger poaching was concerned, Sundarbans had a fairly good track record with five cases detected in the last one decade, Raha says.

He suggested a thorough genome-mapping programme to pinpoint the exact location of tigers.

"Over the last 100 years, eco-separation of tigers from the Kanha, Sundarbans and Tarai regions has isolated them into distinct categories. There is no cross-interaction between these groups. They have developed genetic traits adapting to their individual ecosystems," he says.