India has 6,327 river dolphins, finds first population survey

“The dolphin estimate for Ganga is 5,689 (range: 5,371-6,024), while 635 dolphins were estimated in Brahmaputra, totalling a population estimate of 6,234 (range: 5,977-6,688) in the surveyed rivers,” the report stated.

PM Narendra Modi released the results of the dolphin population survey during the 7th meeting of National Board for Wildlife held Monday at the Gir National Park. He launched Project Dolphin on August 15, 2020.

The survey was done by Wildlife Institute of India, state forest departments of Punjab, UP, Bihar, Assam, Jharkhand, Rajasthan and non-profit organisations including Aaranyak, World Wildlife Fund, Turtle Survival Alliance and Wildlife Trust of India.

Of the 6,324 Gangetic dolphins, 3,275 were found on the river’s main stem, 2,414 were found in Ganga’s tributaries while 584 were found in Brahmaputra’s main stem. A total of 28 rivers were surveyed by boat for the estimation exercise and 30 river stretches were mapped by road.

Among range states, 2,397 dolphins were counted in UP, 2,220 in Bihar, 162 in Jharkhand, 95 in Rajasthan and Madhya Pradesh, 815 in West Bengal, 635 in Assam and three in Punjab.

In Ganga, a total of 7,109 km was actively surveyed, which included the main stem of Ganga as well as its tributaries – Chambal, Yamuna, Rapti, Sharda, Ghaghara, Mahananda, Kosi, Gandak, Geruwa, Rupnarayan, Torsa, Kaljani, Churni, and Haldi, covering UP, Bihar, Jharkhand, West Bengal, Madhya Pradesh, and Rajasthan.

In UP, the highest encounter or concentration of dolphins was found in the 47-km stretch of Bhind-Pachnada in Chambal River.

The Kanpur-Vindhyachal stretch of 380 km had an encounter rate of 1.89 dolphins/km. The dolphin population in 366-km long Narora to Kanpur stretch was almost non-existent, the report said.

In Bihar, the survey found dolphin populations thriving in most stretches due to relatively higher water depth owing to tributaries such as Ghaghara, Gandak, Kosi and Son, coupled with ideal river morphology. The stretch from Chausa–Manihari, covering the Ganga’s main stem has 1,297 dolphins in 590 km, making it one of the most densely populated stretches.