60.
South Asian River Dolphin
(Platanista gangetica)
EN
Overview
A stocky freshwater dolphin, characterised by a long beak containing large, visible teeth. Like most river dolphins, this species has little need for vision in the muddy waters it inhabits, and as a result has tiny, non-functional eyes that lack lenses. Individuals use echolocation to detect food and navigate, and – to a very small extent – for communication. The species lives in one of the most densely populated areas of the world. It is threatened primarily by the damming of rivers for irrigation and electricity generation, which degrades habitat, isolates populations and prevents seasonal migration. Concerted conservation action is needed if this species is to survive.
Urgent Conservation Actions
Surveys to assess distribution, abundance and availability of suitable habitat, further research into the main threats, public awareness programmes and the creation of additional protected habitat.
Distribution
Ganges-Brahmaputra-Meghna and Karnaphuli-Sangu river systems of Bangladesh and India, and the Indus River of Pakistan. A few individuals survive in Nepal.
Fact
Until the late Pliocene, the present-day Indus, Ganges and Brahmaputra (except for the upper reach, the Yarlung Zangpo Jiang) rivers constituted a single westward-flowing river called the Indobrahm. Even up until historical times there was probably sporadic faunal exchange between the Indus and Ganges drainages by way of head-stream capture on the low Indo-Gangetic plains, between the Sutlej (Indus) and Yamuna (Ganges) rivers (Rice 1998).
Associated Blog Posts
26th Sep 13
Manish Datta is an EDGE fellow working on the South Asian river dolphin in Bangladesh. In his first EDGE blog he describes his love for the species and intro...  Read

18th Apr 12
The Ganges River Dolphin (Platanista gangetica) is not your conventional ‘Flipper’: they are virtually blind and live in murky rivers; they aren’t ...  Read

4th Nov 11
Earlier this week Bangladesh announced that three areas in the southern Sundarbans mangrove forest will be declared sanctuaries to protect Ganges river dolph...  Read

24th Feb 11
Last month five Indus River dolphins (Platanista gangetica minor) were found dead in Pakistan with three females and a male found at the village of Ali Wahan...  Read

6th Jul 10
Asian river dolphins are among the most threatened large vertebrates, because the regions where they occur have high human population densities, resource ove...  Read

Media from ARKive
ARKive video - Ganges river dolphin breaching
ARKive image - Ganges river dolphin swimming
ARKive image - Ganges river dolphin swimming at water surface
ARKive image - Ganges river dolphin diving at water surface
Evolutionary Distinctiveness
Order: Cetacea
Family: Platanistidae
Traditionally all river dolphins were grouped together into the family Platanistidae. However, genetic studies have shown that they represent a convergent group of only distantly related species, which are superficially similar to one another – for example, having reduced eyes - because they have each evolved in similar riverine environments. The ancestors of the Ganges and Indus River dolphins are now thought to have represent one of the earliest divergences within the odontocete (toothed whale) clade, after it separated from the mysticetes (baleen whales) during the Oligocene (30-35 million years ago). Indian river dolphins diverged after the Physeteridae (sperm whales) but before the divergence of the beaked whales, Chinese and South American river dolphins, marine dolphins and porpoises. The platanistid lineage was highly successful over the past 30 million years; it diversified into many different species, the fossils of which are known from marine sediments around the world. The Ganges River dolphin is the sole survivor of this once diverse cetacean group. Two subspecies are recognised: Platanista gangetica gangetica (Ganges River dolphin) and P. g. minor (Indus River dolphin).
Description
Size: 
Length: 1.5-2.5 m
Weight: up to 150 kg
A stocky freshwater dolphin characterised by a long beak that widens at the tip. The beak can reach up to a fifth of the dolphin’s body length, and contains large visible teeth. The dorsal fin is undeveloped compared to other dolphins and looks like a low triangular hump. Both the flippers and the flukes (tail fins) are large and broad. The colouration is dark grey or grey-brown above and lighter, occasionally pinkish below. The forehead is steep and rises abruptly from the base of the snout. The eyes lack lenses, leaving the species unable to resolve images; the most the dolphins can do is perceive the presence or absence of light. Females are generally larger than males and may have longer rostrums.
Ecology
Individuals spend most of their time feeding and travelling alone, although groups of 5-7 are sometimes seen in areas where the current is relatively weak and there is a high abundance of prey. Small fish and invertebrates are the main prey species. Most feeding takes place in shallow areas at or near the bottom, with the dolphin swimming on one side and probing the substrate with its beak or flipper. Individuals use echolocation to detect food and navigate, and – to a very small extent – for communication. The dolphins migrate seasonally according to fluctuations in water levels. They spend the dry season in deep pools or the main channels of the river systems, and migrate upstream to the tributaries following the monsoon. Births may take place throughout the year, but appear to peak in December-January and March-May. A single calf is born every two years. Juveniles are weaned at around one year of age, but do not reach sexual maturity until around 10 years of age. This species is thought to live to around 28-30 years in the wild.
Habitat
This species is found in freshwater river systems. In the river basins in India the dolphin is present mostly in plains with slow-flowing rivers. In Nepal it is found in relatively clear waters and rapids. In both areas, however, there is a preference for deep waters. The dolphins tend to concentrate in areas of high prey availability and reduced flow, such as eddy counter-currents.

In Pakistan, the dolphins generally occur in the deepest river channel and are less common in secondary channels. Reported habitat preferences include channel constrictions, confluences (where rivers or streams converge), and deep water.
Distribution
The Ganges subspecies was formerly distributed throughout the Ganges-Brahmaputra river system of India, Bangladesh, Nepal, and possibly Sikkim and Bhutan. Its distribution has declined less dramatically than the Indus River dolphin. Today it is found in the Ganges-Brahmaputra-Meghna and Karnaphuli-Sangu river systems of Bangladesh and India. A few individuals survive in Nepal in the Karnali River and possibly the Sapta Kosi River.

The Indus subspecies formerly ranged throughout the 3,500 km Indus river system in Pakistan. Today the majority of the dolphins are restricted to less than 700 km of river. The majority of the remaining population is found in the mainstream between the Sukkur and Guddu barrages in Sind Province. There are two small additional subpopulations between the Chashma and Taunsa barrages and the Taunsa and Guddu barrages in Punjab and NWFP Provinces. A few individuals still remain above Chashma Barrage and below Sukkur Barrage
Population Estimate
Surveys of portions of the range of the Ganges subspecies have collectively accounted for 1,200–1,800 animals, but the true population is believed to be larger. The entire current range of the Indus subspecies was surveyed in 2001 and resulted in an estimate of 843–1,171 individuals, with a best estimate of about 965.
Population Trend
Decreasing.
Status
Classified as Endangered (EN A2abcde) on the 2010 IUCN Red List of Threatened Species.
Threats

P. gangetica gangetica lives in one of the most densely populated areas of the world. It is threatened primarily by the damming of rivers for irrigation and electricity generation, which degrades habitat, isolates populations and prevents seasonal migration. More than twenty barrages (low, gated diversion dams) and eighteen high dams have been constructed in the Ganges-Brahmaputra-Megna and Karnaphuli-Sangu river systems alone since 1956, and in the northern Ganges tributaries at least three of six subpopulations that were isolated by barrages have recently disappeared. Many individuals swim downstream through barrage gates during the wet season, but are unable to return in the dry season due to strong downstream hydraulic forces at the gates. Further declines are expected as more barrages are planned and under construction throughout the species’ range. The proposed Ganges-Brahmaptura inter-link canal and dam project, expected to be completed in India in 2016, will involve additional dam construction and diversion of water from rivers inhabited by dolphins. This will undoubtedly result in further habitat loss and degradation, population fragmentation, and an increase in dolphin strandings. Pollution by fertilisers, pesticides and industrial and domestic effluents are responsible for the death of many fish and are likely to have a negative effect on dolphin populations. Other threats include deliberate killing of the animals for their meat or oil (used as catfish bait), and accidental entanglement in fishing nets. The latter is a severe problem for this species since its preferred habitat is often in the same location as primary fishing grounds.

Conservation Underway
The species is legally protected throughout its range. It is listed on Appendix I of CITES and Appendix I of the Convention on Migratory Species (CMS or the Bonn Convention). However, poaching still occurs in some areas, and greater enforcement of laws is required. The Upper Ganga River (Brijghat to Narora, in the state of Uttar Pradesh) has been declared as a Ramsar site because of the presence of dolphins there. The population in this stretch has doubled in the last 10 years due to conservation work conducted by WWF-India along with the local community. The Vikramshila Gangetic Dolphin Sanctuary, between Sultanganj and Kahalgaon in the mainstem of the Ganges River in Bihar, India, was designated as a protected area for dolphins in 1991, although until recently there has been little enforcement of protective measures here. In a few smaller tributaries, dolphins receive nominal protection by virtue of the fact that small portions of their habitat are within or adjacent to national parks and sanctuaries (e.g. Kaziranga National Park in Assam, India; National Chambal Sanctuary in Madhya Pradesh, India; Royal Bardia National Park and Katerniya Ghat Gharial Sanctuary, respectively north and south of the Nepal-India border). It has been recently found that fish oils can be used in the place of Ganges River dolphin oil for the preparation of bait; popularization of fish oil bait will hopefully reduce the poaching of the dolphin for its oil.

In Pakistan, the area between the Sukkur and Guddu Barrages was declared a dolphin reserve in 1974 (the Sindh Dolphin Reserve), and dolphin counts here show an apparently increasing trend from 1975 to 2001. Two additional sanctuaries, the Taunsa Wildlife Sanctuary (est. 1983) and the Chashma Wildlife Sanctuary (est. 1984) in Punjab Province also appear to be helping to arrest the rapid population declines. A programme sponsored by the United Nations Development Programme (UNDP) to rescue dolphins trapped in irrigation canals and return them to the Indus mainstream has had some success in reducing mortality.
Projects

This project will investigate by-catch levels of entangling gear types and the use of dolphin products for South Asian river dolphins in the north-eastern Sundarban mangrove forest and adjacent areas. It will increase awareness of fishing communities about freshwater dolphins and ongoing efforts to protect them in collaboration with students from local educational institutions

Conservation Proposed
Although the population has declined dramatically, it is still large enough to be viable in the long-term if adequate conservation measures are taken soon. The International Whaling Committee (IWC) recommends that surveys be carried out to assess the current distribution and abundance of the species, and to assess the availability of suitable habitat. Further research into the main threats facing the species is required in order to implement effective conservation measures. Education and public awareness programmes are crucial to conservation efforts as many local people are unaware of the dolphin’s protected status and regulations. The creation of additional areas of protected habitat and/or dolphin sanctuaries may be required to ensure this species’ long-term survival.

In Pakistan, efforts to ensure the Sindh Dolphin Reserve population remains well-protected are crucial, as is the creation of additional areas of protected habitat upstream of the Guddu Barrage. The International Whaling Committee (IWC) recommends that priority be given to monitoring the survival and movement of dolphins rescued from irrigation channels. Surveys should also be carried out to assess the current distribution and abundance of the species, and to assess the availability of suitable habitat. Further research into the main threats facing the species is required in order to implement effective conservation measures. In particular, the effects of barrages and canal gates on dolphin movements need to be determined. Finally, education and public awareness programmes are crucial to conservation efforts as many local people are unaware of the dolphin’s protected status and regulations.
Associated EDGE Community members

GWild will wear ONLY 12 outfits in 12 months for 12 threatened animals to fundraise for their conservation.

Involved in the conservation of the Ganges River Dolphin in west Nepal.

I am a student of Wildlife Ecology and currently involving in Dolphin conservation in Western Nepal.

I am the Assistant Programme Manager for South and Central Asia at the Zoological Society of London.

I am an EDGE Fellow working on South Asian river dolphins in Bangladesh.

Links
Aaranyak
Aaranyak, a registered conservation NGO working in North East India since 1989, has initiated a project entitled “Conservation of Gangetic dolphin in Brahmaputra river system, India" in collaboration with Dibrugarh University (Assam). The project aims to evaluate the conservation status of the Ganges River dolphin throughout the entire Brahmaputra river system by carrying out research into the species’ population status, distribution, habitat preferences and threats. The data collected will be used to inform the development of a conservation strategy and subsequent conservation action for the species.

Project leader: Wakid Abdul
Contact details: wakid@rediffmail.com

Whale and Dolphin Conservation Society (WDCS)
The Vikramshila Biodiversity Research and Education Centre (VBREC), led by Dr Sunil Chaudhary, together with the Whale and Dolphin Conservation Society (WDCS), the Environmental Biology Laboratory of Patna University, and T.M. Bhagalpur University, has initiated a project to improve the conservation value of the 50km Vikramshila Gangetic Dolphin Sanctuary. One of the most important accomplishments has been the development of the Vikramshila Conservation Action Plan.

WWF India
The Dolphin Conservation Programme of WWF-India has been engaged in various activities to conserve the habitat of the Ganges River Dolphin and secure a future for the endangered species. The Action Plan prepared by WWF-India in 1997, has been under implementation to bring about a sustainable improvement in the status of the Dolphin.

Key contact: Sandeep Behera (Freshwater- Species)
Address: WWF-India, Secretariat, New Delhi (IN) Main Office
T: +91 11 41504813

References
Convention on Migratory Species (CMS): Platanista gangetica, Ganges river dolphin

Nikaido, M., Matsuno, F., Hamilton, H., Brownell, R. L. Jr, Cao, Y., Ding, W., Zuoyani, Z., Shedlock, A. M., Fordyce, R. E., Hasegawa, M. and Okada, N. 2001. Retroposon analysis of major cetacean lineages: The monophyly of toothed whales and the paraphyly of river dolphins. Proceedings of the National Academy of Sciences of the United States of America 98(13): 7384-7389.

Nowak, R. M. 1999. Walker’s Mammals of the World. Sixth edition. The Johns Hopkins University Press, Baltimore and London.

Reeves, R. R., Smith, B. D., Crespo, E. A. and Notarbartolo di Sciara, G. 2003. Dolphins, Whales and Porpoises: 2002-2010 Conservation Action Plan for the World’s Cetaceans. IUCN: Gland, Switzerland.

Smith, B.D. & Braulik, G.T. 2008. Platanista gangetica. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4. <www.iucnredlist.org>. Downloaded on 12 November 2010.

Distribution map based on data provided by the IUCN Global Mammal Assessment.

if you can provide new information to update this species account or to correct any errors, please email us at info@edgeofexistence.org


Forum comments

There are as yet no comments for this species.

Add a comment

You must log in to post. If you don't have a login, it's easy to register.