Bengaluru: On Wednesday (December 18), India radio-tagged – for the first time – a Gangetic river dolphin.
The species, listed by the IUCN Red List as endangered, is mostly found in the Ganga and Brahmaputra rivers systems in India and is also the country’s national aquatic animal.
The radio-tagging is part of “Project Dolphin” and was conducted by the Union environment ministry, the government-run Wildlife Institute of India, the Assam forest department and Guwahati-based conservation NGO Aaranyak.
This radio-tagging – which involves attaching a small tag that emits radio signals onto an animal – will provide invaluable information on the river dolphin’s movements, helping scientists understand many aspects of its ecology such as its home ranges, distribution, movement along rivers, and more. And if applied properly, these data can help scientists develop efficient conservation strategies to protect the species.
Though the Gangetic river dolphin is protected under the Wild Life Protection Act of 1972 and listed under Schedule I (that’s essentially protection on par with that given to tigers in India), the species faces several threats, including underwater noise pollution caused by moving boats and vessels, and the fragmentation of the Ganga and Brahmaputra due to dams and barrages.
First Gangetic river dolphin tagged in India
On Wednesday, scientists with Dehradun’s Wildlife Institute of India and the Aaranyak NGO attached a radio-tag to a male Gangetic river dolphin in collaboration with the Union Ministry of Environment, Forest and Climate Change and the Assam forest department.
The radio-tagging endeavour, funded by the National Compensatory Afforestation Fund Management and Planning Authority, comes under the aegis of Project Dolphin, a conservation initiative on the lines of Project Tiger announced by Prime Minister Narendra Modi in 2020.
As per a press release by the ministry, the tags are lightweight and emit signals compatible with Argos (which has several satellites as part of its system and helps collect and relay environmental data), despite the short surfacing time (of a few seconds) of the river dolphins; the tags are also “designed to minimise interference with dolphin movement”.
The ministry plans to radio-tag Gangetic river dolphins across other states as well.
Union environment minister Bhupender Yadav called the radio-tagging a “historic milestone for the species and India” that would “deepen our understanding of conserving our National Aquatic Animal,” on X.
Happy to share the news of the first-ever tagging of Ganges River Dolphin in Assam—a historic milestone for the species and India!
This MoEFCC and National CAMPA-funded project, led by the Wildlife Institute of India (@wii_india) in collaboration with Assam Forest Dept and… pic.twitter.com/2lSUHVltBN
Advertisement— Bhupender Yadav (@byadavbjp) December 18, 2024
Scientists who have studied the species and its river habitats agree.
“This is a very welcome and promising development which will be a pioneering step in knowing more about the movement ecology of this difficult-to-study species,” said Nachiket Kelkar, who heads the Riverine Ecosystems and Livelihoods programme at the Wildlife Conservation Trust.
Kelkar, also a member of the IUCN Cetacean Specialist Group, has studied both the Gangetic river dolphin and some of the river systems it lives in in India.
What’s radio-tagging and why is it important?
Radio-tagging refers to the process of attaching a radio tag – that emits radio signals that scientists can track, even in real time – onto an animal. This produces data on the animal’s movement: across times of the day, and across days, seasons and years.
Scientists can then analyse the movement patterns of the radio-tagged animals to study several aspects.
They can study what areas or habitats (in the case of Gangetic river dolphins, what depths and lengths of the rivers) they use more or less, and why; average how much each individual moves daily (which will give an estimate of the home range of the animal, which is the area that an animal uses for its daily needs, to live and to reproduce); and whether its movements differ across seasons.
Scientists can also use other ecological data to understand what factors determine these movements, and changes in the animals’ movements if any.
According to a press release by the environment ministry, the project to radio-tag Gangetic river dolphins across its distribution in India has been initiated “given the paucity of information on Ganges River Dolphin habitat needs, movement pattern or home-range information”.
“The tagging exercise will help in understanding their seasonal and migratory patterns, range, distribution, and habitat utilisation, particularly in fragmented or disturbed river systems,” the ministry’s press release said.
And the habitat of the Gangetic river dolphin is both particularly fragmented and disturbed in India.
Along the Ganga, for instance, dams that divert water for both irrigation and hydropower have cut the river into several fragmented bits, preventing river dolphins from moving between these fragments.
The water flow in these stretches are modified for human use by barrages – so these stretches also witness very low water depths, which are a problem for river dolphins.
A part of the Ganga – from Prayagraj in Uttar Pradesh to Haldia in West Bengal – is a national waterway (National Waterway 1). This also includes a stretch in Bihar, which is protected as the Vikramshila Gangetic Dolphin Sanctuary.
A study in 2019 by Kelkar and other scientists here found that the high vessel traffic and the resulting high underwater noise caused by the vessels’ propeller blades drowns out the echolocating clicks produced by the river dolphins to forage, move and communicate.
And authorities continue to dredge the river to maintain the waterway, which increases turbidity and can release toxic metals into the water.
All these could be telling on the animals: not just their stress levels, but their populations too. As per an estimate quoted in a technical report submitted by the WWF in 2021, there are just around 5,000 Gangetic river dolphins in the world.
Experts that the WWF team contacted also ranked the poisoning of river dolphins due to industrial or agricultural effluents and dolphin deaths due to entrapment in fishing nets as some of the major threats to the species in Indian river systems.
