The population of the endangered Gangetic river dolphin is on the rise at the Vikramshila Gangetic Dolphin Sanctuary, India's only dolphin sanctuary, located in Bihar. It was revealed by a latest census study conducted by a team of experts at the Vikramshila Biodiversity Research and Education Centre, officials said on Wednesday.
"The population of dolphins recorded in the surveys are indicative of the fact that the population of the endangered species is on the rise," said Sunil Choudhary, a coordinator at the VBREC.
Choudhary said that the dolphin population is constant despite their deaths reported because of getting accidentally trapped in fishing nets in the sanctuary area.
Another expert, Nachiket Kelkar said that the team has used double platform method, otherwise known as capture and recapture method, is capable of addressing both availability and perceptions of biases in dolphin counting to a large extent.
Choudhary said the double platform method had been successfully adopted for the first time in Bangladesh and it was replicated by the VBREC team in dolphin sanctuary.
There is little chance of error or failure in recording of dolphins by this method. He said that successive surveys were undertaken between October 2011 to June 2012 in the Vikramshila Dolphin Sanctuary, which is spread over 60 km along the River Ganga in Bhagalpur district.
"In all three surveys, we counted 200-plus dolphins in the sanctuary, "he said.
"Dolphin counting is a big challenge for scientists worldwide. But our team of experts managed to record number of dolphins in the sanctuary in three different ranges," Choudhary said.
VBREC had started the dolphin census in 1998. At that time, the population of the aquatic animal stood at just 95-98. In 2008, 170 dolphins were counted. Set up in 1991, the sanctuary has reported frequent killings of the aquatic animal in the last one year.
Gangetic river dolphins fall under Schedule I of the Indian Wildlife (Protection) Act and have been declared an endangered species by the International Union for Conservation of Nature.