Gangetic River Dolphin Numbers Decline in Assam

Local folklore of the Mising people (an indigenous community) has facilitated a reverence for rivers and their wild inhabitants over the centuries. The story features a Mising woman named Yakashi, who was inept at household chores. As people from her community grew bored of her incompetence, they decided to throw Yakashi in the river. However, instead of drowning, she turned into a dolphin.

The Mising people don’t kill the Gangetic river dolphins, or ‘xihus’ as they are known locally in Assam. However, they have noticed a decline in dolphin populations over the years. Krishna Pegu, a Mising farmer from the river island Majuli (in Assam) says, “Even a few years back, we would see pods of dolphins regularly. However, now we might only sporadically see a dolphin near Majuli.”

Rapidly declining populations

The Gangetic river dolphin, which is both the national aquatic animal and state aquatic animal of Assam, is a Schedule-1 species under the Wildlife Protection Act, 1972, and is also considered ‘endangered’ by the International Union of Conservation of Nature (IUCN). While dolphins once thrived in Assam, across Brahmaputra and its tributaries like Kulsi and Subansiri, the species is currently struggling. When the action plans were formulated for their revival, conservationist and journalist Mubina Akhtar told Mongabay-India that most of these plans failed to create the desired impact.

“For instance, the Species Recovery Programme launched by the Ministry of Environment, Forest and Climate Change (MoEFCC) in 2016, targeted a recovery plan for the Gangetic dolphin. It focused on regular population monitoring and factors affecting the species and their habitats across their range, which also included Assam. However, even after constant monitoring of the species and its habitat, threats to their existence continue to loom large,” said Akhtar.

Elaborating on the threats, she added, “Subansiri dolphins face severe threats from the dams upstream. Sand mining and other developmental activities make Kulsi dolphins all the more vulnerable. Further, the construction of a 1.5 km. wall in Domukha by a multinational tobacco company located at Bortezpur in Kukurmara has jeopardized the Kulsi dolphins. Surveys confirmed the presence of about 40 dolphins at a 2.5 km. stretch, at the confluence of the Kulsi and the Batha rivers. The Kulsi dolphins have become all the more vulnerable as many of the wetlands in the area that supply abundant fish into the Kulsi on which the dolphins survive, have been transformed into industrial land banks.”

Last year, a report published by the Wildlife Institute of India (WII) confirmed that the Brahmaputra river system remains a major stronghold for the Gangetic river dolphins, harbouring 30% of its world population. Kulsi and Subansiri also harbour a significant population.

Dolphins are present in national parks like Kaziranga and Orang, as they enjoy sufficient protection there. Apart from that, dolphin hotspots in Brahmaputra are at Sivasagar, Tezpur, Guwahati and Goalpara.

Barak, the other major river system in Assam, once harboured a good population of dolphins. However, now they may be approaching local extinction, with only a handful of them found in tributaries like Kushiyara at the Bangladesh border.

Perils of sand mining in Kulsi

The Kulsi tributary originates from West Khasi Hills of Meghalaya and bifurcates into two main channels upstream at Kulsi village in Kamrup district of Assam. It is known for being one of the main habitats of dolphins in Assam — the WII report estimates about 32 dolphins here. However, since the last few years, the flow in one channel has drastically declined to a staggering extent, affecting not only dolphins, but other aquatic fauna as well.

 Local communties say that unregulated mechanised sand mining in the area has led to the river drying up. Prasanna Kalita, a local environmentalist who is vocal about the conservation of dolphins, said, “Sand mining has been going on here since many years. However, earlier it used to happen manually and not much damage was done. Now, mechanised sand mining is happening and as a result the river is drying up. As there is no fish, population of dolphin is also being risked. Also, there are many fishing villages on the bank of Kulsi and more than 10,000 people used to earn their livelihood from fishing. Now, majority of these fishermen are working as daily wagers or some are even working with the sand miners.

”Dimpi Bora, Divisional Forest Officer (DFO), Kamrup said, “We have conducted raids into these sand mines and have seized 150 machines. However, the problem is that there is huge demand for Kulsi sand in big cities like Guwahati. If they don’t get sand from Kulsi, then the entire construction business in Guwahati can come to a standstill. So, even if we take action like collecting fines from the trucks carrying sand, it is met with resistance from a lobby as it increases the construction cost in Guwahati. We are trying to ensure that sustainable mining takes place. Also, more than 5,000 local youth are working in the sand mines. So, if we have to bring them out from there, we need to provide them with an alternative source of employment. So, we are imparting training on jewellery making, handicraft, bee keeping and also how to join paramilitary forces.”

Bora added that dolphins face other threats apart from sand mining in Kulsi. “Industrial effluents dumped into the river are also affecting the population of dolphins. Last year, three dolphins died in my area. A forensic report revealed that two died from organo-phosphate poisoning which is used in agriculture and one died from bacterial infection.”

This year, an expert committee was formed by the Deputy Commissioner of Kamrup to analyse causes of river degradation and promote dolphin conservation and local livelihood security. The committee submitted its report in March 2022, recommending a complete ban on mechanised sand mining in Kulsi river. The report also emphasised the maintenance of Standard Operating Procedures (SOPs) to protect dolphins from developmental activities, and suggested conducting of investigations on abundance, distribution, ecology and threats, along with studying climactic patterns that may aid a long term conservation plan.

Mega dams that are proposed along northeast rivers are another threat to dolphins. Subansiri, the largest tributary of Brahmaputra, harbours nearly 48 dolphins in a 93 km stretch, according to WII. Populations have been known to fluctuate, falling to as low as 14 when dolphins move mainstream during the river’s leanest months, when natural flows are at their lowest. However, the 2000 MW Subansiri Lower Hydroelectric Project (SLHEP), a dam under construction, is a potential threat to the dolphin population of Subansiri. An example of how it can play out is already seen in the Ranganadi in Arunachal Pradesh where the Ranganadi concrete gravity dam is established and in the lean period, the river loses connectivity with Subansiri river. “[The] Gangetic river dolphins in Ranganadi [river have] have been completely wiped out,” the WII report states, stressing the importance of protecting the Subansiri so that it does not have the same fate.

Jugal Borah, a conservationist from Lakhimpur who has been studying dolphins on the bank of the Subansiri said, “Currently, Subansiri has a good population and the habitat is stable. In 2011, North Lakhimpur College did a survey where they found 27 dolphins. I think now the number will be more than 40. I have counted 20 dolphins on a stretch of 25-30 km. on the bank. However, if the Subansiri dam is constructed, it will become a major threat for dolphins here.”

Excessive poaching in Barak

P. Biswas, a professor who taught Life Sciences at Dibrugarh University, spent his childhood at Dilkhush tea garden in Cachar district of Assam, where his father worked. “In the early 1960s, we remember seeing a lot of dolphins in the Barak river. There was a place called Naraindah in the upstream near Assam-Manipur border which was a very good habitat for dolphins. However, in 1985, a group of people came from Bihar to Naraindaha and rampantly killed dolphins in that area. After 1995, no dolphin was seen at Naraindaha. Dolphins have a pungent smell so there is not much demand for their meat. However, their oil was sold widely. Dolphins were mainly killed using gill nets at that time,” recalls Biswas. Dolphin oil is believed to have medicinal qualities.

After the large-scale killing of dolphins, they became almost extinct in the Barak river system. Research scholar Amir Sohail Choudhury told Mongabay-India, “The Barak river bifurcates at Teenganga near Bangladesh border and there the river divides into Kushiyara and Soorma in Karimganj district. A handful of dolphins are found in that area. The present dolphin population is also facing several disturbances in the Barak river system. There are around 30 sluice gates in Barak which interrupt the prey base of dolphins. Also, the 1,500 MW Tipaimukh dam which is constructed on Barak River will decrease depth of the river and thus further impacting dolphins.” Choudhury co-authored a paper titled The endangered Ganges river dolphin heads towards local extinction in the Barak river system – a plea for conservation along with Nazrana Begam Choudhury, Mohammed Khairujjaman Mazumder, Himabrata Chakravary.

The way ahead

WII has also conducted another survey on the status of dolphins and its findings will be published later this year. Abdul Wakid, Program Scientist, Campa, Dolphin at WII said, “This is a national survey from Punjab to Assam where we have studied rivers like Beas, Chambal, Ganga and Brahmaputra. In Assam, dolphin killing due to poaching, and the use of gill nets for fishing are major issues. In 2008, we started a body called Dolphin Conservation Network with two members at 30 places each. Their vigilance has helped to bring down poaching to a large extent. 

As dolphins are blind and use echolocations to find objects, they often get entangled in fishing nets. So, on an experimental basis, we used a device called ‘pinger’ which was fitted with the nets. These devices send out a signal and as a result dolphins avoid the nets where pingers are fitted.”

On the possibility of dolphin tourism, such as that being conducted at the Vikramshila Gangetic Dolphin Sanctuary in Bhagalpur district of Bihar, Wakid said, “Dolphin tourism is possible [on the Brahmaputra]. In Guijan, Tinsukia, people come to watch dolphins. However, the sound of boats affects the echolocation process of dolphins. If we consider dolphin tourism seriously, then we also need to ensure that dolphins are not disturbed by the initiative. When I was working in the USA as a visiting scientist, I went to the Gulf of Mexico in Florida to watch manatees and dugongs. Those places are zero speed zones with signboards displaying zero km. They can’t speed up even if chased by a storm. So, if we start dolphin tourism here, we will have to abide by these rules for the sake of dolphins.”

This story was first published in Mongabay India