Fishermen with a dolphin’s carcass. Telegraph picture

Patna, Oct. 8: The river dolphins, which enjoy the status of a national aquatic animal in India, are facing extinction threat on some stretches of the Ganga and its tributaries.

In 2006, dolphins became extinct in the Yangtze river in China. It was a major jolt to wildlife lovers across the globe.

The Yangtze river used to be replete with these mammals and made an important part of the river eco-system. Intensive fishing accompanied by heavy pressure of river traffic left little scope for the Yangtze river dolphins (Lipotes Vexillifer) to survive. They could not sustain the pressure and became extinct.

One should not be surprised if the same happens to the Gangetic dolphin (Platinista gangetica gangetica). “Around a 100-km-long-stretch of river Ganga between Haridwar and Bijnore has become dolphin-less. Fishermen have confirmed this fact,” said R.K. Sinha, the head of environmental science department of the Central University, Bihar, who is also known as the dolphin man of India.

Giving reasons for the dwindling number of dolphins, he said the construction of a barrage on the river course at Bijnore in 1984 led to this situation.

Dolphins, which used to go upstream right up to Haridwar from Bijnore side, could not do so after the construction of the barrage.

The dolphins caught between the barrage and Haridwar became isolated. With the passage of time they became extinct there. Now not a single dolphin is visible on this stretch of river Ganga.

Something similar has happened on the 225-km stretch of river Sone, which flows through Bihar and meets Ganga near Haldi Chhapra, around 25km west of Patna.

“Dolphins used to enter Sone from Ganga at Haldi Chhapra. They used to travel fair distance upstream into the Sone river. But the construction of Rihand and Bansagar barrages on Sone river in Madhya Pradesh and Indrapuri barrage in the Bihar led to reduction of water flow in the river. It acted as a deterrent for the movement of dolphins in the river course.

“Excessive human activity due to sand mining at Haldi Chapra was the final nail in the coffin as dolphins stopped moving upstream. This led to their complete disappearance from the stretch of Sone river in Bihar,” Sinha said.

He said such trends are very alarming. These show that natural habitat of the Gangetic dolphin is being reduced due to human interference.

In the long run, it may prove to be a major hurdle in conservation of this aquatic animal.