From next year, the environment and forest department will conduct an annual Gangetic dolphin census in the 525km stretch of the Ganga between Chausa in the west and Manihari Ghat in the east.

Deputy chief minister Sushil Kumar Modi, who holds the environment and forest department charge, said on Thursday at the Dolphin Day function at Eco Park.

Gangetic dolphins were declared as India's national aquatic on October 5, 2009, after chief minister Nitish Kumar and dolphin expert from Patna R.K. Sinha convinced the then central government. The state observes October 5 as Dolphin Day since 2012.

At the Dolphin Day event on Thursday, Sinha underlined the need of keeping a regular tab on numbers of the animal, whose presence is the sign of a healthy river ecosystem.

Sinha and his team had conducted the last dolphin census in 2012 and it is estimated that Bihar is home to around half of the estimated 3,000 Gangetic dolphins in the country.

Modi announced that a 24-seater boat service would be launched by the end of this month in Bhagalpur. 'Apart from giving visitors the chance to have a glimpse of dolphins, the service would also take tourists to Bateshwar Sthan temple and Antipur where remains of the ancient Vikramshila University lie,' Modi said.

The environment and forest department will give cash awards to fishermen who rescue dolphins from accidental death, Modi said after fishermen's representative Ramashish Choudhary Nishad highlighted the efforts of a fisherman from Fatuha who had saved three dolphins but his effort went unnoticed.

Vivek Kumar Singh, the environment department principal secretary, said the proposed National Dolphin Research Centre in Patna was held up due to some technical issues raised by Patna University, on whose land the centre is to come up. Modi said he would discuss the issue with the vice-chancellor.

S.A. Hussain of the Wildlife Institute of India spoke about an upcoming study by the institute this year to assess the number of dolphins.