River dolphins, fish, and fisheries in Bangladesh

Asian river dolphins are among the most threatened large vertebrates, because the regions where they occur have high human population densities, resource overexploitation and environmental degradation, with escalating pressures on local biodiversity and diminishing ecosystem services.

Tragically we have already been witness to the extinction of the Yangtze River dolphin or Baiji. Efforts to better understand the key factors threatening the Ganges River dolphin with extinction have already begun in the Assam region of India, however funding has recently been secured to extend research down into Bangladesh throughout the Ganges-Brahmaputra-Meghna and Karnaphuli river systems. Funding is for a three year PhD project based here at ZSL but in collaboration with Julia Jones of University of Bangor, and Dr. Simon Northridge of the Sea Mammal Research Unit in St. Andrews. The project shall build upon some of the current research being done by the Wildlife Conservation Society’s (WCS) Bangladesh Cetacean Diversity Project which has already started documenting habitat preferences, abundance hot spots, and resource use in this species.

This species is considered to be particularly threatened by overfishing (incidental by-catch, direct exploitation, resource depletion), and high industrial and agricultural pollutant loads may also have a severe impact on dolphin immunocompetence and fertility. However, although these threat processes are known to constitute major causes of mortality in cetacean populations worldwide, almost no information is available on the interactions of Ganges River dolphins with fisheries or fish stocks, and similarly little is known about either observed levels or predicted health effects of persistent organic pollutant loads in the species. In the absence of such data, it is effectively impossible to assess the conservation status of the species across its range, or to develop appropriate sustainable recovery strategies.

The purpose of this project is to identify patterns and drivers of river dolphin mortality, and the relationship between regional river dolphin abundance and the status of commercially significant freshwater fish species (e.g. hilsa shad). Data on the timing, cause and distribution of river dolphin mortality events (including both incidences of by-catch and other events) will be gathered during an extensive interview survey of knowledgeable informants from riverside fishing communities across Bangladesh. During the survey additional data shall be collected on fishing gear type and use in different parts of the river system during both high- and low-water seasons, data on fish catch size and composition for target fisheries representing important resources for local communities. Further data on fishing gear use, and landings shall be obtained from the Bangladesh Fisheries Research Institute. In order to look at pollutant loads in the dolphin, tissue samples shall be obtained from carcasses and returned to the UK for analysis.

The findings of this study shall both provide an important insight into the major factors contributing to the decline of this highly threatened species and therefore identify appropriate conservation recommendations, but shall further develop the effectiveness of monitoring  techniques employed when studying cryptic, aquatic species such as this.

The project will officially start at the beginning of October, but work is already underway to plan for a field season in early 2011. A one month trip is planned for November/ December 2010 in which Dr. Sam Turvey (project principal supervisor) and Nadia Richman (PhD student) will go to Bangladesh to meet with the WCS team and discuss the logistics of fieldwork across the country.


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  1. Shamir Biswas said,

    on July 6th, 2010 at 9:37 pm

    Really really happy to see this effort going into the conservation of the Gangetic River dolphin. All the best to the team!

  2. Ronald Blom said,

    on July 8th, 2010 at 7:39 am

    We need more atention for the River Dolphins.
    Thats why i make this face book,River Dolphins of the Planet.
    Please write en feel free to post on this facebook. Its there for people to now and see how importand it is to do wat ever we can to protect them.
    Your team is amasing leds make sure people in the world get the ight information.

  3. Anup said,

    on September 9th, 2010 at 6:25 am

    Good effort this. I’m interested to know what’s the plan for the India side of P. Gangetica conservation? Forest Dept does not have infrastructure, Vikramshila Dolphin Sanctuary isn’t doing well and so on. I’m glad you’re doing this in Bangaldesh but do let me know if you have plans for the India side and if so when would you be visiting and posting updates on efforts there? Personally I’m going to visit Vikramshila around end of Sept/early October this year, I live in Singapore, and I am interested in getting things going, hands on, in order to help with conservation of these beautiful mammals in their habitat (India or Bangladesh side).

  4. Gitanjali Bhattacharya said,

    on September 13th, 2010 at 5:07 pm

    Thank you for your interest in the Gangetic River Dolphin, Anup. They are indeed in need of urgent conservation attention. ZSL (with support from UK government funded Darwin Initiative) is working in partnership with Aaranyak, Guwahati based NGO working in the field of biodiversity conservation in North East India to support river dolphin conservation in the Brahmaputra river.

    The three year project will focus on key conservation outcomes which include a coordinated framework of institutionalised dolphin monitoring and reporting systems across the Brahmaputra River system in Assam, providing baseline information for targeted conservation action. The project aims at enhanced relationships and goodwill with local communities across a network of identified dolphin priority sites through targeted education and awareness programmes, fostering deeper understanding and ownership of the river ecosystem and the plight of the dolphin as an indicator species. The programme endeavours to contribute towards long term dolphin conservation by setting up community-based “stewardship” conservation developed in two identified priority dolphin areas, providing a model for replication across a network of identified protected/community-based conservation areas in the Brahmaputra River.

    More information about the project and regular updates on the project will be available at http://www.zsl.org/conservation/regions/asia/river-dolphin-india/

  5. Shamir Biswas said,

    on October 2nd, 2010 at 6:00 pm

    Hi Anup, if you really want to get a chance to see the Gangetic River dolphin, I would strongly recommend you not go to Vikramshila, since from what I have heard, the sanctuary (like most Indian wildlife sanctuaries) is in a dilapidated condition, and there is a very minute probability of seeing one of the few dolphins that remains there.

    Instead, you should head to a place called Kukurmara, which is 40kms ( 1 hr drive) outside Guwahati, Assam, where in a tiny river called the Kukurmara, there lives a family of around 40 river dolphins. The fishermen of this village have lived in peace with these dolphins for centuries in this peaceful amicable little village, and to the extent that they are willing to give their lives for their protection. More info here:


    Truly applaud the initiative of ZSL and C-NES to take a step forward and try and prevent the extinction of this truly remarkable, yet helpless, gem of evolution.

  6. Anup said,

    on November 7th, 2010 at 5:57 am

    Hi Gitanjali, sorry for the late response. Yes, I have heard of Aaranyak’s efforts in Assam and also read some of Dr. Wakid’s research since I last posted. Thanks for the link you have provided. All the best to the Dolphins!

    Hi Shamir, since my comment, I have been in touch with Prof. Sinha of Patna Uni, known as the Dolphin man of India. There are stretches of the Ganges also that supports a small number of Dolphins. I’d definitely go to Assam sometime but the kind Prof. has also offered to take me to places on the Bihar stretch of the Ganges and show me GD’s. They are in dire straits in the Ganges, I was told, by Prof. Sinha and this needs to change. The problems are similar to those of the GD population in the Brahmaputra tributaries but perhaps the Ganges has additional problem of heavy metal/chemical discharge in huge quantities and sewage of course. Poaching and boat traffic is another common problem. There’s a plan forming for conservation of the Ganges GD’s also and I hope to be a part of that effort. Thanks again guys, hats off to those doing such good work in the areas you have described.

  7. said,

    on December 30th, 2010 at 12:37 pm

    I have been working for conservation of Ganges River Dolphin since 1990 in Brahmaputra Drainage. Being the first river dolphin researcher in Brahmaputra, I conducted the first ever systematic dolphin census in Brahmaputra in 1992-93, 2nd census in 1997 and after that the 3rd in the year 2002, made worldwide campaign about the conservation need for unique Kulsi River Residential dolphin population in Assam, studied extensively on the dolphin-oil bait fishing, introduced fish-oil as a substitute of dolphin oil for its use in bait fishing in Brahmaputra in 1995, started alternative livelihood rehabilitation program for the fisherman involved in dolphin-oil bait fishing from 1997. After putting all these efforts for over a decade, the people of Assam had come to know about the existence and importance of River Dolphins in Brahmaputra. While sharing my experiences, I seriously feel that nothing much have so far been changed in the context of conservation of this important species. There were many projects undertaken, many studies carried out, but the animal is continue to loose its fate in these waters. Brahmaputra is a vast water body, taking intervention even in one-tenth of it is almost near to impossible with the kind of technology & resources available and policies in place. It needs international cooperation, political will and huge amount of resources to be applied with cooperative technologies. Lets do something which can really help….

    Dr. Sujit Bairagi, PhD
    Founder & Chariman
    Dolphin Foundation
    Guwahati, India

  8. Gopal Khanal said,

    on June 17th, 2013 at 4:47 am

    I am really glad to know such research efforts in Bangladesh. I am also concerned that despite the most threatened status of the upstream isolated population of dolphin in the Karnali of Nepal above the Kailaspuri barrage, little is done from national and international level conservation stakeholders level. Handful efforts of local community are not adequate to ensure their long term survival in the waters of Karnali. Thus, I urge all stakeholders to do their best for conservation of dolphins in the Karnali.

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