Patna: A team of scientists from Wildlife Institute of India (WII), Dehradun, and officials from the state's Valmiki Tiger Reserve took part in a preliminary survey programme on Friday to assess the presence of dolphins in river Gandak.

Led by senior WII scientist Qamar Quereshi, the team surveyed about 40km of the stretch of the river during the daylong programme for which the environment and forest department had provided logistics.

The information gathered through the preliminary survey will be used during the detailed survey work the WII will conduct on Gangetic dolphins in February-March next year.

"The Centre had commissioned the work to the WII to conduct survey of four critically endangered animals - dolphins, dancing deer of Manipur, the Great Indian Bustard and Dugong (a marine species) - and suggest ways to protect these animals. The dolphin survey work is part of that work," said Quereshi, sharing details with The Telegraph.

Quereshi is heading the WII team that would conduct the study on dolphins.

Gangetic dolphins, which enjoy the status of national aquatic animal, are generally found in river Ganga and its tributaries and the Brahmaputra. Of an estimated population of about 2,500, around 1,500 of these aquatic mammals are found in Bihar in river Ganga and its tributaries.

The senior WII scientist said during survey, the scientists would also study the impact of various development works like plying of ships, dredging of river and construction of ports on its habitat.

He said during the preliminary survey in which inputs would be gathered based on observations made in the field, special emphasis would be laid on identifying the areas where the scientists should focus mainly while conducting the detailed survey and past records too would be used while finalising the suggestions based on the preliminary survey.

Unlike the past observation-based survey, the one conducted on Friday was done using the standardised protocol developed by the WII for collecting data from the field.

As far as the final survey is concerned, WII has decided to take help of all the agencies and individuals who are working for conservation of dolphins. "We would take help of dolphin expert R.K. Sinha, Bhagalpur university, Zoological Survey of India and Wildlife Trust of India during the final survey programme and we would be open to include others as well to enrich the survey work," Quereshi said.

He pointed out that special gadgets had been developed using which one could see well below the surface of the water and the same would be used by the survey teams.

The WII is also planning to engage fishermen in the conservation work of the Gangetic dolphins and it is now experimenting with a device fitted in the nets of fishermen and dolphins, which sometimes get killed after getting trapped in these nets, don't come near the nets once they sense the presence of the gadget.