Till now, pug marks were used to count the tigers, but there was always controversy regarding the veracity of the marks.
During the 2006 census, the state government had rejected the Indian Statistical Institute's claim that there were not more than 70 tigers in Sunderbans, the world's largest delta.
"Sunderbans is not like Buxa or any other tiger reserve. The terrain here is very difficult and requires a special method. So we will go for DNA sampling which will be used for the first time to estimate the number of tigers," Sunderbans Biosphere Reserve (SBR) director Pradeep Vyas said.
The census would be held in January and February next year. DNA profiling of the tiger's scat will be done to count the animals, he said.
"It will provide the exact number of big cats in the mangrove habitat. We are sure we can do it," Vyas said, adding that lightweight 'tiger guards' would be provided to the scat collectors.
The scats would be sent to the Centre for Cellular and Molecular Biology for DNA sampling. Wildlife Institute of India would also be involved in the census which would be done in phases, the SBR director said.
Besides DNA sampling, camera trapping would also be used for the count, Vyas said, adding that about 250 cameras would be positioned in different areas in the world heritage site depending upon tiger density.
Wildlife experts also feel that there should be a proper method for tiger count in Sunderbans.
"The mangrove habitat of the Sundarbans require innovative methods to get an accurate picture of the tiger population there," Wildlife Protection Society of India director Belinda Wright said.
Biswajit Roy Chowdhury, a member of the state wildlife board who has worked in the Sunderbans for a long period, also said considering the difficult terrain and vast area, a special method was required for tiger census.
In the pug mark method, the fresh left hind imprints were collected from the field and analyzed.