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South Asian River Dolphin: Is It Endangered?

South Asian River Dolphin: Is It Endangered?

River dolphins are one of the most endangered animals on the planet, with just two species remaining. The south asian river dolphin is among them and is declining at a higher rate than any other freshwater cetacean, with a population count as low as 2,400 individuals.

The south Asian river dolphin requires our assistance! Here’s what you need to know about south Asian river dolphins and why they require our aid!

We need to do more to protect south asian river dolphins from extinction. Join us by donating today or take action for south Asian River Dolphins now!

  • Status: Endangered
  • Known as: South Asian River Dolphin, Blind River Dolphin, Ganges River Dolphin, Ganges Susu, Indus River Dolphin, Susu.
  • Estimated numbers left in the wild: +/-2000.

Description

The river dolphin is characterized by its long pointy nose, thickening towards the end, large steeply rising forehead, small eyes, brownish/grey skin, and stocky build.

They are typically solitary creatures and usually spotted on their own or in loose groups. They do not ordinarily form tight interactive groups.

The river dolphin is essentially blind because It lacks a crystalline eye lens. Despite the lack of an eye lens, it still has the ability to detect the intensity and direction of light in the murky waters in which it inhabits. The river dolphin hunts and navigates using a method called echolocation or biological sonar.

This method involves the animal emitting calls and listening to the echoes that return from various objects in the surrounding environment and enables the river dolphin to locate and identify objects.

In place of a dorsal fin, the river dolphin has a small, triangular lump.

Its flippers are thin and are considered large compared to its body which generally reaches approximately 2 to 2.2 meters in males and 2.4 to 2.6 meters in females. The oldest recorded South Asian River Dolphin was a 28-year-old male who was measured at 199 centimeters.

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Location

Native to freshwater rivers located in Bangladesh, India, Pakistan, and Nepal.

They are most commonly found in waters abundant in prey consisting of various shrimp and fish (carp and catfish) and a reduced water current.

River dolphins are split into two subspecies, namely the Ganges and Indus. The Ganges subspecies inhabits the Ganges- Brahmaputra- Meghna and Kampaphuli-Sangu river systems of Bangladesh and India with small populations located on the Ghaghara River and Sapta Kosi River.

The Indus subspecies can be found between the Sukkur and Guddu barrage in the Sind Province of Pakistan.

Behavior

The river dolphins are mostly solitary, but they may congregate in groups of three or ten. Despite their largely solitary existence, these river dolphins may be found in loose gatherings especially at tributary junctions, when prey gather.

Nudibrancinus gigas has a unique swimming style, in which it swims on its sides while submerged. In captivity, however, swimming speed was 5.4 km/hr, but this may not be representative of the species’ actual underwater swimming ability. The longest wild dive was 3 minutes long and the longest was 1 minute and 35 seconds.

A south asian river dolphin is most active between 8:40 pm and 3:58 am, peaking at 11:32 pm.

They are opportunistic feeders, meaning they hunt prey which they perceive has the highest chance of easy capture. This could mean any animal that cannot detect its approach or is relatively slower than itself. They tend to survey large areas of deep water where prey is most abundant, and circle repeatedly to snatch prey with their long snout.

Accomplishments/Evolutionary adaptations

The south asian river dolphin is the only species that belongs to its genus, meaning that it is uniquely evolved for life in freshwater rivers. They are able to generate and perceive sound in a unique way that is different from all other animal species: most notably, they are able to determine the intensity and direction of an object by bouncing sound off it.

They also lack a nasal organ for olfaction (the sense of smell). They compensate for this with vision and echolocation.

South Asian River Dolphins are in danger of extinction in the wild; their population is declining at an extremely rapid rate.

The IUCN (the International Union for the Conservation of Nature) has designated the south Asian river dolphin as one of the world’s most endangered species, going extinct in its natural habitat.

This rapid decline in south asian river dolphin numbers is the result of three main factors:

  1. Fishing nets used in dams and barriers pose a deadly hazard to south Asian river dolphins by entanglement and drowning.
  2. Changes in water quality or habitat loss for certain fish species that south asian river dolphins need for food have resulted in a decrease of prey species.
  3. A drop in prey species due to human activities along the south asian river dolphin’s habitat, leading to deterioration of the natural environment and shrinkage in food animals.

The northern river dolphin is still on the CITES list, which means that international trade in southern asian river dolphin specimens is prohibited.

The south Asian river dolphin is also covered by Appendix I of the CMS (Convention on Migratory Species), which means that all nation states will protect south asian river dolphins within their own borders and collaborate internationally to do so.

The south asian river dolphin is listed on Appendix I of the Convention on the Conservation of Migratory Species of Wild Animals (CMS).

Most south asian river dolphins live in freshwater rivers and not saltwater, this is because south asians have evolved to hunt and navigate using echolocation and not sight.

South Asian River Dolphins lack a nasal organ for olfaction (the sense of smell) and compensate with vision and echolocation.

Distribution

The South Asian river dolphin, like other river dolphins, is a freshwater mammal that may be found in South Asia regions such as Pakistan, Nepal, India and Bangladesh. They migrate seasonally – downriver when water levels are lower and upriver when water levels are higher.

These river dolphins rely heavily on freshwater river systems to survive, making them an incredible species that is extremely rare.

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Feeding behavior (Ecology)

The fish-eating Indus river dolphin’s echolocation skills and long snouts are used to find various benthic animals, including fish and invertebrates. Some experts estimate that they consume more than 1 kg of food each day.

The common carp is a popular sport fish because of its high yield and mild flavor. It has few, if any, natural predators but is frequently preyed upon by locals.

The P. gangetica minor variety is known to consume catfish, herring, catfish, carp, gobies, mahseers and prawns. A small number of natural predators exist, including tigers, crocodiles, and some species of large fish.

Prey is caught by use of the teeth which are used to grasp prey before swallowing it whole.

Prey differs across regions due to different mixes of available fish within differing portions of south asian river dolphin habitat range. For example, one study found that most common carp were between 200 and 250 mm in length, but south asian river dolphins preyed on fish of greater than 300 mm in length.

Carried out by researchers at the National Institute of Hydrology (NIH) in Roorkee, India-based study suggests that south asian river dolphin numbers are declining more rapidly than any other freshwater cetacean: their population has declined by 82.2 percent over the last century and they could be as low as 2,400 individuals.

In Pakistan south asian river dolphins are found mainly in the Indus River from Jammu to Karachi with a small number of sightings south of Hyderabad, near Thatta on the Pakistani side of the Indus.

These south asian river dolphins are found in the Indus, Ganges and Brahmaputra rivers in India, Nepal and Bangladesh.

There has been a study of the dolphin population in India since 2005. The study is along the Ghaghra River in Uttar Pradesh, which is south of Lucknow. The dolphins in this region are smaller than their counterparts in other parts of Asia, suggesting that there may have been a bottleneck (a small number) of dolphins at one point.

It’s believed that there are around 1,100 south Asian river dolphins in the wild today, and it’s been claimed that their number is decreasing.

There are nine (9) separate species of the River Dolphin. One (1) of them is already extinct and another one (1) is dying and we don’t know if it will come back.

Many threats confront South Asian River Dolphins. Fast speed boats and fishing net entanglements pose a hazard to these freshwater fish that reside in Nepal, India, and Bangladesh’s freshwater areas.

Their food, as well as their habitat, is also under attack: south asian river dolphins feed on such things as catfish, carp, gobies, mahseers, and prawns; they rely on their senses to find them.

There are only 2,000 south asian river dolphins left in the wild. The number is decreasing every year. A recent study by NIH in India suggests that south asian river dolphin numbers are declining more rapidly than any other freshwater cetacean.

South asian river dolphins are getting smaller. It is estimated that these dolphins have gone down by 82.2%. There are less than 2,400 south asian river dolphins left in the world today. These south asian river dolphins live mainly in Pakistan but there are sightings of them near Thatta on the Indus River.

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Conservation

The Ganges River dolphins are currently listed as a critically endangered species on the IUCN Red List. They are both hunted for meat and oil and are at risk of being caught in fishing gear during their passage.

In numerous ways, the Indian river dolphin is becoming increasingly uncommon. Hunting, construction of dams, and altering rainfall patterns are all factors that have contributed to their decline.

They were previously included on the list as endangered in the 1970s. The current population of Dolphins is believed to be between a hundred and a thousand individuals—a quantity insufficient to sustain the species.

Hunting has been one of the largest factors in the south Asian river dolphin’s decline in population numbers. They are hunted for meat and oil, while their fat is used as a cure-all in many cultures. Dolphins are even killed by fishermen to prevent them from eating caught fish.

This statement led to an investigation into the matter which found that in some villages, nearly 25% of the dolphin’s meat catch was dolphins.

It is considered an endangered species, like other river dolphin populations, for its risk of becoming extinct. It faces many threats including degradation of habitat, depletion of prey species, entanglement in fishing gear and small population size.

The south Asian river dolphin’s habitats are threatened by the pollution they cause (including toxic waste dumping). Not to mention, dams built on south Asian rivers has blocked their route for feeding.

The Ganges River Dolphin is protected under the Indian Wildlife Protection Act, 1972. However, the south Asian river dolphin still falls under a major threat from hunting and fishing nets.

Conservation efforts have been made to bring this species back from the brink of extinction including the south Asian river dolphin’s conservation project in Bangladesh which includes both captive breeding and reintroduction into the wild.

The Indian south Asian river dolphin conservation project is more of an education and awareness program than a direct conservation project.

It is aimed at teaching people about the south asian river dolphin and why they need protecting.

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Threats

Exploding human populations in the Ganges drainage area threatens the natural habitat of the river dolphin due to strains on the natural resources.

They also face threats as rivers are dammed for irrigation and electricity, which results in river dolphin populations becoming isolated and seasonal migration being prevented.

They are further threatened by pollution, boats, hunting, and human disturbance. They are hunted for food and oil and often become trapped in fishing nets.

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Conservation efforts

The South Asian River dolphins are protected on Appendix I of the Convention on the International Trade in Endangered Species (CITES). They are also listed in the Agreement on the Conservation of Small Cetaceans of the Baltic and North Sea (ASCOBANS) and protected under the Indian Wildlife Act.

See Related: Endangered vs. Threatened vs. Extinct

Organizations

Do you know of or are you a part of an organization that works to conserve the South Asian River Dolphin? Then please contact us to have it featured on Our Endangered World.

Frequently Asked Questions (FAQs)

What does the snout on a south Asian river dolphin do?

The south Asian River Dolphin has a long narrow snout. The snout contains an elongated upper and attached lower jawbone with attachments for muscles of mastication and feeding. This makes the south asian river dolphin an unusual looking cetacean that is also largely unknown or misunderstood by many people worldwide!

Why is the south Asian river dolphin endangered?

The south Asian river dolphin, the only other freshwater cetacean besides the Amazonian manatee, is threatened by pollution, habitat destruction and hunting.

Are South Asian river dolphins extinct?

No, south asian river dolphins are not yet extinct! They are classified as critically endangered by the International Union for Conservation of Nature because there are only 2,400 left. There is less than 1% of the world’s population of these animals in the south asian river. We need to help them now!

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