New method likely to yield more accurate count of the endangered species
The annual Ganges river dolphin census, undertaken by World Wide Fund for Nature-India in collaboration with the Uttar Pradesh Forest Department along about 250-km-long riverine stretch of Upper Ganga between Hastinapur Wildlife Sanctuary and Narora Ramsar site began in Bijnor on Wednesday.
Unlike previous years, when direct counting method was used, this year the tandem boat survey method is being used, said M. Semmaran, District Forest Officer, Bijnor.
Dr. Semmaran told The Hindu that the method, developed by the renowned river and marine ecologist Gill Braulik, provides a more accurate count of the endangered species. “Here the officials use two inflated boats which move in tandem to count the dolphins. After collating the data, statistical tools are employed to arrive at the final count. In this process, we don’t announce the number of sightings on a daily basis.” Ms. Braulik, who is known for her work on Indus river dolphins, is also participating in the census.
The forest official added this year the upstream of Bijnor Ganga barrage up to Balawali has also been included. It has added around 30 km to the area being covered by the census which will conclude on October 15.
Stable numbers
Mohd. Shahnawaz Khan, coordinator, WWF-India, said that last year the count was 33, including three calves. “Starting from 22 in 2015, the number has been stable in the last few years. We expect a rise this year.” Mr. Khan lists the dumping of single-use plastic, industrial pollution, fishing and dredging as some of the threats to dolphins in the region. “The increase in the number of barrages and dams is also affecting their growth as such structures impede the flow of water,” said Mr. Khan.
From mythological significance to a tourist attraction, the mammal is at the top of the riverine ecosystem. “It is among the four ‘obligate’ freshwater dolphins in the world. Its presence indicates the health of the riverine ecosystem,” said Mr. Khan.
The animal is known to make strange sounds when it breathes, earning it the sobriquet ‘Susu’. “Being a mammal, it has to come to the surface to breathe,” said Mr. Khan. It is also called a blind dolphin because it doesn’t have a crystalline eye lens and uses echolocation to navigate and hunt. “It is crucial to find prey in the murky waters of the Ganga. Like bats, they produce high-frequency sounds which helps them ‘see’ objects when the sound waves bounce off them,” said the WWF-India coordinator.
He praised the local population’s role in the region in saving the riverine ecosystem. “Often, they are the first ones to inform us of any development that requires our intervention.”