India’s Indus Dolphins: Very Few, Very Threatened
In 2008, upstream from the Harike Barrage, scientists discovered a small population of the endangered Indus river dolphin. Science writer Aathira Perinchery analyses relevant studies and speaks with experts to understand if they have a future in India.
Photo: Mohd. Shahnawaz Khan.
Barely 50 km. from where tourists marvel at Amritsar’s world-renowned Golden Temple, a little-known, yet fascinating aquatic animal navigates the turbid waters of the river Beas. Here, in a 70 km. stretch of the river, dwells India’s only population of Indus river dolphins, or bhulan, as they are locally known. Recent studies show that only 18-35 of these dolphins remain here, and human activities including fishing and construction along riverbanks are affecting the survival of these endangered mammals.
Photo: Mohd. Shahnawaz Khan.
The River Dolphins of South Asia
British explorers discovered the South Asian river dolphins Platanista gangetica that inhabited the rivers of India, Bangladesh, Nepal and Pakistan in the early 19th century. The dolphins found in the 3500 km.-long Indus river system (comprising the Indus and its tributaries Ravi, Jhelum, Chenab and Sutlej) though, were marginally different: smaller and with a slightly varied skull structure, apart from being completely isolated from those in the Ganga and its tributaries. Today, science recognises the dolphins inhabiting these two river systems as two separate sub-species. While the Gangetic river dolphin Platanista gangetica gangetica dwells in the Ganga and its linked rivers, those in the Indus river system are the Indus river dolphins Platanista gangetica minor.
What fascinated early explorers was that South Asian river dolphins are almost blind. Their small, bead-sized eyes are sunk into their heads, almost as if put there as an evolutionary after thought. That’s because in the murky waters of the silt-laden rivers they live in, eyes don’t serve much purpose. These eight feet-long cetaceans use their heightened echo-locating skills – much like bats do – to both prey on bottom-dwelling fish and prawns, and to move around in their riverine habitats.
However, the dolphins’ movements were affected when the British began building barrages – low-walled dams comprising several gates that help divert water for irrigation to canal systems – across the large rivers in their colonies.
The Indus was no exception; work on the barrages commenced in the early 1900s. While the barrages were a godsend for farmers, it sounded the first death knell for Indus river dolphins. They could not move upstream or downstream, and were stranded between barrages. With India’s independence and the ensuing partition, Pakistan became home to the fragmented river stretches where the Indus river dolphins dwelled. Research shows that as of 2011, around 1,450 individuals remain in Pakistan in five fragmented populations split between six barrages on the Indus, while dolphins in the tributaries of Jhleum, Chenab, Ravi and Sutlej have been completely wiped out.
India’s Indus dolphins
Two Indian tributaries feed the Sutlej river in Pakistan: the Sutlej and the Beas. These Himalayan-born tributaries flow through the plains of Punjab in India and merge at the Harike Barrage, less than 35 km. from the India-Pakistan border. It was here, upstream from the Harike Barrage to Beas city on the Beas river, that Indian scientists - in a rather unexpected but heartening discovery - confirmed the presence of a population of Indus river dolphins in 2008.
But how many dolphins survive here? Which parts of the river do they use? The Punjab government auctions fishing rights across most of its rivers to contractors every year; so does fishing and allied human activities affect the dolphins in any way?
Intrigued, Mohammed Shahnawaz Khan, Senior Project Officer at the World Wildlife Fund-India, set out to answer these questions in April 2011.
Demarcating the river into seven segments of 10 km. each, Khan and his team scoured the river in boats moving at a constant speed (but slowing down in what they thought were prime dolphin habitats), for dolphin sightings within each segment for 10 hours a day, for two entire years. While looking out for dolphins, Khan’s team also collected information on the river’s flow: the presence of deep pools and circular movements of water called eddies. They also checked the river and its banks for signs of human activity including fishing, construction along riverbanks and pollution.
Photo: Mohd. Shahnawaz Khan.
Understanding the River and its Dolphins
To understand the dolphins, Khan had to understand the river and its flow.
The Beas is both rain and glacier-fed. The southwest monsoon – which hits Punjab in late June and continues till August – coincides with summer glacial melts in the Himalaya, resulting in a surge in water levels during these months.
“This ‘high flow’ season sees the flooding of low-lying areas,” says Khan. Water depth in the Beas increases to up to 4.5 metres during this time.
As the monsoon lets up in September and October, the river eases back to normal water levels. In November, the onset of winter in the Himalaya arrests glacial thaw, causing a fall in water levels till February. Lack of rains during this season fragments river sections into patches of deep pools. Khan calls this the ‘low flow’ season, when water discharge in the river is at its bare minimum.
According to Khan’s research, dolphins moved upstream during high flows because the increased water level created new habitats. However, during low flows, they were restricted to habitats downstream. “At this time, the dolphins have no choice but to restrict themselves to areas that have deep pools,” says Khan.
“It is a useful study and it concurs very well with what we know from other places; that the dolphins are concentrated in areas of deep pools during the low water seasons,” says cetacean expert Gillian Braulik of the Wildlife Conservation Society, who studies the species in Pakistan. “And that this is also where human activity is concentrated – with fishing and ferry activities."
Khan’s work (published in the journals Marine and Freshwater Research in October 2016 and in Current Science in December 2016) also shows that there may be only 18 to 35 individuals of the Indus river dolphin in the Beas in India, a number he derived by using dolphin occurrence data from the different sections of the river.
“The entire 70 km. distribution range of the dolphins in India needs to be protected,” says Khan. Considering that such a small population survives in an area where there is intense fishing and pollution, Khan says that the government should also withdraw fishing contracts in the entire 70 km. span of the Beas where the dolphins are found.
Photo Courtesy: Mohd Shahnawaz Khan.
“That is a much bigger issue than only river ecology, it also relates to fishermen’s well-being,” says Braulik. And will it not antagonize locals to the cause of conserving the species in India? Yes, agrees IUCN Cetacean Specialist Group member Nachiket Kelkar, who studies the Gangetic river dolphin in Bihar. While studying ecological mechanisms, the social context and economic realities of contract systems need to be studied, he adds. Paskolos-internetu.eu - greitieji kreditai internetu visiems - nedirbantiems, automobiliui su vekseliu iš privačių asmenų, paskolų refinansavimas be užstato, sms kreditas, vartojimo paskola be užstato ir t.t.
“I would surely recommend working with contracts to come up with dolphin-friendly means of conducting fishing operations. Contracts at least systematize the process, making it easier to regulate fishing. Suppose contracts were abolished (this happened in Bihar), imagine what would happen in an open-access? Everyone will come in and fish the way they want to. I know from a contact in Punjab that fishermen used to kill bhulans for oil to use as fish bait. So just withdrawing fishing contracts without supplanting them with wiser and ecologically better systems, will be an overall lose-lose.”
Braulik quotes a similar situation that played out in Pakistan’s Sindh district in 2011, which she says, turned out to be quite bad for the Indus river dolphins there. “With the change from the contractor system to one where individual fishermen could buy licenses more cheaply, there were more fishers, and, more unskilled fishers. Then there was a sudden spike in dolphin mortality. Within a year after the contractor system was abolished, about 45 dolphins in Sindh were found dead. So it may be a good thing for social equity and a better system for fishermen, but it may in fact harm the river ecosystem and the dolphins,” she says.
In the case of the dolphins, community-based conservation measures may be a wiser and more productive road to take. “The sustainable use of natural resources can be recommended for the local community. And the scale of sustainable human activities should be within the dolphin tolerance range,” says Khan.
Photo: Mohd. Shahnawaz Khan.
“In Bangladesh, they’ve identified deep pool habitats and work in collaboration with the fishing community to declare small areas as protected. It is on a small scale, but is community-led and managed,” says Braulik. Similarly, Khan's work also recommends that management interventions be focused on “identified havens for dolphins during the low-flow season.”
While management interventions may need to be recommended with a lot more caution, Khan’s work generates important preliminary data on the newly-discovered bhulan – the second most-endangered cetacean in the world – in India.Aathira Perinchery is a trained wildlife biologist who was smitten by science journalism. She freelances as a science writer and is currently pursuing a post-graduate diploma in journalism in Chennai, Tamil Nadu
Author: Aathira Perinchery.