Bhagalpur, Sept. 3: Experts have claimed that the floods in the Ganga are unlikely to cause any permanent migration of Gangetic dolphins, primarily at Vikramshila Gangetic Dolphin Sanctuary in Bhagalpur.

Though residents have claimed that sighting of Gangetic dolphins and many other aquatic animals have dipped drastically following the floods, experts claim that the animals would return as soon as the floodwater recedes.

R.K. Sinha, professor of zoology at Patna University, who has worked extensively on the Ganga and Gangetic dolphins, claimed that shifting of Gangetic dolphins from the Vikramshila sanctuary to small tributaries of the Ganga and floodplains in monsoon is an annual phenomenon.

"Floods, as such, mostly have positive impact on aquatic animals. When the water level in the Ganga rises during monsoon, small fishes tend to shift to the riverine areas or small tributaries of the Ganga in neighbouring areas. As Gangetic dolphins feed on small fishes, they also follow them to riverine areas and tributaries of Ganga. This happens every year but the dolphins as well as fishes return to the Ganga as soon as the water level recedes in the river," explained Sinha, also known as the Dolphin Man.

Residents have claimed that the sightings of Gangetic dolphin and other animals at Vikramshila sanctuary have reduced over the past couple of weeks. "I used to take a bath daily at Barai Ghat, where the sighting of dolphins was common. However, I have not seen a single dolphin in the past 15 days, when the water level increased," said Ramsaroop Mandal, a resident of Barari.

Experts claimed that dolphins are sure to return. "Gangetic dolphins shift in monsoon almost every year, when the water level in the river rises. They go to small tributaries and floodplains to avoid high current and in search of food (fishes)," said Gopal Sharma, a scientist at Zoological Survey of India, Patna.

Apart from Gangetic dolphins, other aquatic species found in the Vikramshila sanctuary, spread across a 68-km stretch of the river from Sultanganj to Kahalgaon, include gharials, six species of turtles, 90 species of fishes. Around 200 bird species of birds also reside in the villages. Fishermen at places such as Sultanganj, Mayaganj in Bhagalpur city and Kagzi tola in Kahalgaon claimed that the sighting of fishes in the river had reduced after the floods.

"Such an incident is common in a flooded river but we can assess the real situation only after the floods. If fishes are available in the river after the floods, then it would indicate the normality of the river," said Bijay Sahani, a fisherman in Kahalgaon.

Sunil Kumar Choudhary, coordinator, Vikramshila Biodiversity Research and Education Centre, said: "There is no primary report of the flood effect on this sanctuary yet. Things could only be ascertained after floodwater recedes. It is very difficult to say about the present condition of the river's fauna and flora."

Sanjay Kumar Sinha, conservator of forests, Bhagalpur division, said: "There are possibilities of migration of dolphins from the flooded Ganga. But this aquatic animal would certainly return to its original habitat after the floodwater recedes."

Choudhary raised the question of safe return of dolphins. "Since the river is spread across a vast area owing to record rise in the level this time, so it is possible that the dolphins might have migrated to the tributaries and other water bodies. We fear some of them might have been trapped in places from where they wouldn't have the opportunity to return to the flow."

Additional reporting by Piyush Kumar Tripathi in Patna