The elusive Ganges River Dolphin

I am perhaps one of the few researchers lucky enough to have seen the elusive Ganges River Dolphin in Nepal where most people do not even know of its existence. In early morning during monsoon of 2016, I got a chance to encounter the species, a mother and a calf at once! However, monsoon isn’t an ideal time for conducting census of Ganges River Dolphin but in Mohana river – the river originating from Chure hills of Nepal it is the only time when dolphins can migrate. As the International Freshwater Dolphin Day on 24th October is fast approaching, I wanted to put pen on paper and write about the current status of the dolphin species.  

Ganges River Dolphin in Mohana River Nepal, Monsoon 2016

Status and distribution

Ganges River Dolphin (GRD) Platanista gangetica gangetica are Endangered species that occur in the Ganges-Brahmaputra-Meghna (GBM) river system and Karnaphuli Sangu (KS) river systems of Nepal, India and Bangladesh occurring from the deltas in the Bay of Bengal – the Indian Sundarbans and upstream to the Himalayan foothills (Sinha and Kannan, 2014; Braulik and Smith, 2019). The distribution range of GRD was reported between 77°E and 89°E, from the foothill of the Himalayas to the mouth of the river in Bay of Bengal in the Ganges basin, “throughout all the main rivers, as far eastwards as longitude 95°E by latitude 27°30’N, frequenting all its larger tributaries” in Brahmaputra river (Anderson, 1879) in the Ganges-Brahmaputra-Meghna river systems, and in the Karnaphuli River (Anderson 1879) and possibly the Sangu River in eastern Bangladesh (Haque, 1976).

The historical range of GRD in the Ganges basin has seen a substantial diminution after the mid-90s especially in the upstream reaches such as in Bhimgoda Barrage, Haridwar – Middle Ganga Barrage, Bijnor section; in Ganges river upstream of Bijnor; and in Yamuna River above the Chambal River confluence – Tajewala near the foothills of the Himalayas (Sinha et al., 2000).

Despite its wide geographic range, the Ganges River Dolphin habitat is distributed patchily. The GBM and KS river systems are disjunct however, there may be occasional demographic interaction between the two systems during the high-water season if the freshwater plumes of the two systems meet. It is separated with the Indus dolphin population with both natural and man-made physical barriers. A recent research has further found that Ganges and Indus dolphin are two separate species (see Braulik et al. (2021)).

Several dams and barrages have been created restricting their movement. From the 1950s through the 1980s, 19 hydropower dams and 23 barrages have been created in the GBM and KS river system (Smith et al., 2000). >50% population size reduction has occurred since 1900s (Braulik and Smith, 2019). The total abundance of GRD in the range (Nepal, India and Bangladesh) was estimated at 3,526 (Sinha and Kannan, 2014).

Some threats faced by the species

The Ganges River Dolphin face multiple threats which has dwindled its population from 4000-5000 in the early 1980s to around 3500 in 2014 in its entire distribution range (Sinha and Kannan, 2014). The threats includes the directed and incidental killing by fishermen, accidental by-catch, effects of dams and barrages impeding their movement, chemical pollution, noise pollution, amongst others (Sinha and Kannan, 2014).

Large dams, flood-control structures, and embankments for irrigation projects and hydroelectric power have had substantial impacts on river ecosystem services, and biodiversity at both local and landscape scales (Dudgeon, 2000; Nilsson et al., 2005). The barrages have led to isolation of the dolphin population upstream from any possible genetic interchange with the ones living in downstream waters (Smith et al., 1994). During flooding periods, the dolphins upstream of the barrage may occasionally move downstream which may result in permanent loss of individuals from Nepal. However, it is also possible that it will move upstream during floods (Khatri et. al., 2010). The imminent threats to the survival of the species might be in the form of India’s megaproject, the Inter-basin water transfer project termed the National River Linking Project (NRLP). This threatens to modify the already depleted and degraded habitat into major dredged shipping lanes (Kelkar, 2017).

Likewise, it is still found that the oil of Ganges River Dolphin is still used as fish bait despite plenty of alternatives being developed (Kolipakam et al., 2020). While it is not known exactly how many dolphins are hunted for oil extraction in its entire range, evidence for the continued use of river dolphin oil for bait fishing and traditional medicine has been obtained. Similarly, non-targeted net entanglement has also been found to fuel the oil-bait fishing and medicinal market. In a small-scale freshwater fishery system, it has been found that fisheries-related bycatch currently exceed the sustainable limit recommended by the International Whaling Commission by 3.5 times (Dewhurst-Richman et al., 2020).

What’s been done to protect this species?

The Ganges River Dolphin has been declared as the National Aquatic Animal and October 5 is nationally recognized as “Dolphin Day” in India. Likewise, the Government of India has also developed a Conservation Action Plan for the Ganges River dolphin 2010-2020 (Sinha et. al., 2010). Similarly, Vikramshila Gangetic Dolphin Sanctuary situated in Bihar, India covering 60 km stretch of the Ganges River from Sultanganj to Kahalgaon is dedicated for the conservation of dolphins. Likewise, the National Chambal Sanctuary situated in northern India has also been established covering 5400 sq. km for the protection of Ganges River Dolphin along with two other Critically Endangered species the gharial and the red-crowned roof turtle. The establishment of Asia’s first Dolphin Research Center at Patna University is also underway for the long-term conservation of the endangered species.

Likewise, the Government of Bangladesh has also developed a Conservation Action Plan for the Ganges River dolphin 2020-2030 (Aziz, 2019). Six wildlife sanctuaries have been established for the protection of Ganges river dolphin and Irrawaddy dolphin in the Sundarbans and Padma-Jamuna confluence which altogether cover only 1,648 ha (BFD, 2017).

Recently, Nepal has also published Dolphin Conservation Action Plan (2021-2025) (MoFE, 2021). The acts which mandates the protection of the endangered species include Aquatic Animal Protection Act 1961 (AAPA), Water Resource Act 1992 and Wetland Policy 2012. However, these acts remain ineffective in conservation of the endangered species. For instance, AAPA protects aquatic life but not wetlands that provide its habitat (IUCN Nepal, 2004). The lack of integrated conservation plans has led to ineffectiveness of the conservation of the Ganges River dolphin.

My reflection on researching about this species

As I had said earlier, my first experience with the species was when I got to be part of the species census which was part of my internship. Even in my limited experience, I have been deeply fascinated with the species. My curiosity has led me to conduct studies on the species which I will be in a better position to discuss in a few months. Luckily, I have also been fortunate enough to be part of a project now dedicated to promote sustainable fishing to conserve the last river dolphins in Nepal. This is a Conservation Follow-Up Award by CLP which will be active in Karnali, Nepal. 

I believe riverine species have not been much highlighted in the conservation arena of Nepal and not much attention has been given to this species from eco-tourism perspective as well (except in Mohana river, I will dive into this further in the days to come!). I distinctly remember during a survey I was conducting at Koshi Tappu, the ticket salesperson did not name Ganges River Dolphin as one of the highlights of the area.

Among the range countries, their number is least in Nepal and the sub-population in Nepal is even considered Critically Endangered (Jnawali et al., 2011). Historically, the freshwater cetacean has been documented in all four major river system of Nepal – Karnali, Koshi, Narayani, and Mahakali, (Shrestha, 1989). GRD however is locally extirpated in Mahakali (that demarcates Nepal’s western border with India; and is called Sharda river in India) and Sapta Koshi river upstream of the Sapta Koshi Barrage (Shah et al., 2020; Paudel and Koprowski, 2020).

There are barrage gates established in Karnali, Koshi and Narayani Rivers, these rivers are subject to limited habitat suitability especially near the barrages. In Narayani, even though some portion of the Narayani lies within the core area of Chitwan National Park, the variability of the water level (and hence deep pools) is largely dependent upon the barrage gates. Likewise, natural flow regime has also been seen to trigger an ecological trap effect in the species in Karnali (Khanal et al., 2016). The Geruwa River was once a preferred habitat for the dolphin, which is protected area as it flows through Bardia National Park. However, following a major flood in 2010 the river flow shifted from the active channel in Geruwa to Karnali which is dominated by fishing and agricultural activities. This has led dolphins to shift from the shallow but a relatively safe habitat to a deeper but riskier one. Thus, their adaptive feature has made them maladaptive in this regard.

The Ganges River Dolphin is not the only member of its genus, but of its family, Plantanistidae, represents an ancient lineage in the order Cetartiodactyla. It would be truly devastating if, they were to get extinct like the Baiji dolphins in China. It has been noted that the threats faced by the Ganges River Dolphin will not be solved through further acquisition of scientific knowledge but requires improved high level policy and strategic river basin planning, stronger environmental impact assessments that specifically address impacts to Ganges river dolphins, or by community level outreach, education and collaboration to reduce anthropogenic threats (Braulik et al., 2021). So, I believe it is high time that the Ganges River Dolphin deserve the conservation attention they require especially in Nepal.


Anderson, J. (1879) Anatomical and Zoological Researches: Comprising an Account of the Zoological Results of the Two Expeditions to Western Yunnan in 1868 and 1875; and A Monograph of the Two Cetacean Genera, Platanista and Orcella-Vol. 1 (Text). Bernard Quaritch.

Aziz, M.A. (2019) Conservation Action Plan for Ganges River Dolphin And Irrawaddy Dolphin of Bangladesh. Dhaka: Ministry of Environment, Forest and Climate Change.

BFD (2017) Protected Areas of Bangladesh. Dhaka: Bangladesh Forest Department.

Braulik, G., Atkore, V., Khan, M.S., Malla, S. (2021) Review of Scientific Knowledge of the Ganges river dolphin. , 84.

Braulik, G.T., Archer, F.I., Khan, U., Imran, M., Sinha, R.K., Jefferson, T.A., Donovan, C., Graves, J.A. (2021) Taxonomic revision of the South Asian River dolphins (Platanista): Indus and Ganges River dolphins are separate species. Marine Mammal Science.

Braulik, G.T., Smith, B.D. (2019) Platanista gangetica: Braulik, G.T. & Smith, B.D.: The IUCN Red List of Threatened Species 2019: e.T41758A151913336.

Dewhurst-Richman, N.I., Jones, J.P.G., Northridge, S., Ahmed, B., Brook, S., Freeman, R., Jepson, P., Mahood, S.P., Turvey, S.T. (2020) Fishing for the facts: river dolphin bycatch in a small-scale freshwater fishery in Bangladesh. Animal Conservation. 23(2), 160–170.

Haque, A. (1976) Comments on the abundance and distribution of the Ganges susu, Platanista gangetica, and the effects of the Farakka Barrage on its population. FAO Scientific Consultation on Marine Mammals, ACMRR/MM/SCI. 132.

IUCN Nepal (2004) A Review of the Status and Threats of Wetlands in Nepal. Kathmandu Nepal: International Union for Conservation of Nature.

Jnawali, S., Baral, H., Lee, S., Acharya, K., Upadhyay, G., Pandey, M., Griffiths, J. (2011) The status of Nepal mammals: the national red list series, department of national Parks and wildlife conservation kathmandu, Nepal. Preface by Simon M. Stuart Chair IUCN Species Survival Commission The Status of Nepal’s Mammals: The National Red List Series. 4.

Kelkar, N. (2017) A river dolphin’s ear-view of India’s waterways development plans. Sanctuary Asia. 37(4), 58–61.

Khanal, G., Suryawanshi, K.R., Awasthi, K.D., Dhakal, M., Subedi, N., Nath, D., Kandel, R.C., Kelkar, N. (2016) Irrigation demands aggravate fishing threats to river dolphins in Nepal. Biological Conservation. 204, 386–393.

Kolipakam, V., Singh, S., Ray, S., Prasad, L., Roy, K., Wakid, A., Qureshi, Q. (2020) Evidence for the continued use of river dolphin oil for bait fishing and traditional medicine: implications for conservation. Heliyon. 6(8), e04690.

MoFE (2021) Dolphin Conservation Action Plan. Ministry of Forest and Environment.

Paudel, S., Koprowski, J.L. (2020) Factors affecting the persistence of endangered Ganges River dolphins (Platanista gangetica gangetica). Ecology and Evolution. 10(6), 3138–3148.

Shah, D.N., Poudyal, A., Sharma, G., Levine, S., Subedi, N., Dhakal, M. (2020) Status, distribution, threats, and conservation of the Ganges River Dolphin Platanista gangetica (Mammalia: Artiodactyla: Cetacea) in Nepal. Journal of Threatened Taxa. 12(1), 15106–15113.

Sinha, R.K., Kannan, K. (2014) Ganges River Dolphin: An Overview of Biology, Ecology, and Conservation Status in India. Ambio. 43(8), 1029–1046.

Sinha, R.K., Smith, B.D., Sharma, G., Prasad, G., Choudhury, B.C., Sapkota, K., Sharma, R.K., Behera, S.K. (2000) Status and distribution of the Ganges susu(Platanista gangetica) in the Ganges River system of India and Nepal. Occas. Pap. IUCN Species Survival Comm.. 23, 54–61.

Smith, B.D., Sinha, R.K., Kaiya, Z., Chaudhry, A.A., Renjun, L., Ding, W., Ahmed, B., Haque, A.A., Mohan, R.S.L., Sapkota, K. (2000) Register of water development projects affecting river cetaceans in Asia. Biology and Conservation of Freshwater Cetaceans in Asia, 22.

Anu Rai

I am an aspiring environmental researcher.

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