Poachers are the foremost threat to the Royal Bengal tiger, says an expert
The number of Royal Bengal tigers in the Sundarbans of Bangladesh has risen to some extent in the last three years.
The rising trend in tiger numbers was found in the latest tiger census, “Second Phase Status of Tiger in Bangladesh Sundarbans 2018,” said sources at the Bangladesh Forest Department on Tuesday.
An event will be organized on Wednesday where the findings will be formally announced at the Hoimonti auditorium of Ban Bhaban (Forest Department) in Agargaon.
According to an earlier census in 2015, a total of 106 tigers were recorded in the Sundarbans, but that number rose to 114 in the 2018 survey.
A Forest Department official, on condition of anonymity, said the second phase census began in 2016 under the USAID BAGH project. Camera trap methods were used to record the number of tigers.
He said the survey was conducted over an extended period of time, starting December 1, 2016. Cameras were set up in 1,659 square kilometres of tiger inhabited areas in the Sundarbans.
Of the total area, 1,208sq km are in Satkhira, 165sq km in Khulna, and 283sq km in the Shoronkhola range of Bagerhat.
A total of 491 cameras at 239 points of the Sundarbans were set up on trees. The cameras captured 2,466 images of tigers for the 249-day census.
The survey report states the number of tigers to be 114.
The USAID BAGH project's first phase survey in 2015 recorded 106 tigers. With this latest report, tiger numbers have increased 8% in three years.
Forest department sources say the draft of the latest survey report was also sent to the Wildlife Institute of India for confirmation of the findings. The Indian institute has confirmed the findings to be accurate.
To be noted, the Bangladesh Forest Department in cooperation with Wildteam, and the Smithsonian Conservation Institute, started the tiger census with United States Agency for International Development (USAID) financing.
The Department of Zoology at Jahangirnagar University also assisted in analyzing the data and preparing the final report.
Fluctuation in tiger numbers
British wildlife researcher, Guy Mountfort, studied the biodiversity of the Sundarbans from 1966 to 1970. At that time, the Forest Department said the number of Bengal tigers was 300 in the forest.
A total of 350 tigers were recorded during a field survey conducted by Bubert Hendrichs in 1975.
In 1982, Margaret Salter carried out another field survey and estimated the number of tigers to be 425.
Another survey by Rex Gittins conducted in 1984, found the tiger population to be between 430 to 450.
In 1992, the forest department collected data from researchers working in the Sundarbans and recorded the number to be 359.
With yet another survey in 2004, the Forest Department said the number of tigers stood at 440, although the accuracy of that survey was debatable.
In 2006, Dr Monirul H Khan, renowned tiger researcher and professor of Jahangirnagar University's Zoology Department, conducted a census using the camera trap method and said the tiger number was 200 only.
Expert's opinion on the rise in tiger numbers
The Forest Department started using the camera trap method to conduct tiger census from 2015. Previously, surveyors would count tiger footprints to determine tiger numbers.
When asked about the reliability of the camera trap system, Professor of Jahangirnagar University's Zoology Department, Dr Monirul H Khan, said: "The camera trap system is the most scientifically advanced method available today to measure tiger population. It is more effective than the footprint count method."
He also said poachers are the principal threat to the very survival of the Bengal tigers.