Dolphins are to rivers what tigers are to the jungle. Being the umbrella species of a river system, dolphins act as a ‘mirror’ to reflect the health of a river. But unlike tigers, whose number may have shown an increase in recent years, river dolphins are falling in number despite being recognised as the National Aquatic Animal. From an estimated 4,000-5,000 in 1982, their population has slipped below 2,000.
However, the trouble with counting river dolphins is the absence of a unified method and timing of census. With critical stretches scattered across the Ganga, Brahmaputra, Yamuna, Chambal, Ghaghra and Rapti rivers, concurrent counting is a daunting task. Consequently, no two surveys are comparable owing to variations in methodology and survey stretches.
A 2012 census along a 2,200-km stretch of the Ganga and its tributaries, involving 150 participants in 18 teams, had counted 671 dolphins. More recently, in October 2015, a survey by 200 members in 20 teams counted 1,272 dolphins along a 3,307-km length of the Ganga, Ghaghra, Rapti and Chambal rivers. The number has seemingly doubled!
“It has, but getting a sense of the numbers is critical for drawing conclusions,” says Suresh Babu, Director — Rivers, Wetlands and Water Policy at WWF, which partnered with the UP Forest Department for the recent dolphin census. “The numbers may have increased, but there are stretches where dolphin numbers have fallen.” Therefore, the rise in number can be attributed to survey of longer stretches and the presence of breeding populations.
Overall, however, there has been a significant decline in the number of river dolphins across habitations. Altered river stretches, pollution of freshwater ecosystems, and bioaccumulation of toxicity are to blame.
Turning a blind eye
River dolphins, also called bottlenose dolphins because of their long beaks, love to swim in freshwaters at speeds averaging 5-12 kmph and up to 32 kmph when there is adequate water depth.
The absence of meaningful estimates of range-wise populations has hindered conversation efforts.
In the latest census, in addition to standardised methodology, a large number of forest officials, civil society members, and local villagers were trained and involved. The month-long exercise had an interesting spin-off, creating awareness about dolphin conservation among nearly 700 locals from 80 riparian villages. Enthused by the response, Prashant Verma, Chief Conservator of Forests (Wildlife), UP, who oversaw the ‘My Ganga, My Dolphin’ campaign, announced that 20 model dolphin conservation villages would be developed along the Ganga and its tributaries.
Engaging communities in the conservation of dolphins is critical as the plethora of wildlife regulations and environmental laws haven’t been as effective in protecting them.
Like many mammals, river dolphins have the unique ability to communicate using sound. In fact, each dolphin has a unique signature whistle it uses to communicate with others of its species. The onus is on us to listen to and recognise their signature whistle for survival.
The writer is Director, The Eco-logical Foundation, New Delhi