"There are only about 2500 dolphins in the Ganga river basin according to a 2006 survey out of which 60 per cent are found exclusively in Bihar," Sinha told PTI.
The dolphins, particularly of the Gangetic variety, were found at the confluence of the Ganga and Saryu rivers at Doriganj in Saran district, the confluence of the Ganga and Gandak confluence at Sonepur in the same district and the confluence of Ganga and Koshi at Kursela in Katihar district.
The decreasing number of dolphins because of water pollution led the Centre to declare it as national aquatic animal in May 2010 and take steps for its protection and conservation, Sinha said.
The central government also recognized dolphins as a highly endangered species under Schedule I of the Wildlife Protection Act, 1972, Sinha said.
The zoologist, who has been working on a campaign to save the dolphin since his students days in 1970s, said that decrease in depth of rivers due to increasing siltation and rise in effluents have led to reduction in habitat of the mammal and decline in its population. MORE