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Will the dolphin bounce back?

Endangered species
Last Updated 31 May 2010, 12:36 IST
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Hindu mythology is replete with stories which are connected to nature. According to one such story, the Goddess Ganga came down to earth from heaven and the Gangetic Dolphin heralded the descent of the holy Ganga. The dolphins are also mentioned in the epic Mahabharatha. However, this special status of the Gangetic Dolphin seems to be restricted to the realm of mythology.

In reality, though, the high levels of pollution in the river has left this graceful mammal struggling for existence. The Ganges River Dolphin (Platanista gangetica gangetica) is restricted to the Ganga and Brahmaputra Rivers and their tributaries in India, Bangladesh and Nepal and surveys show that only about 2000 of them remain in these rivers.

Indicator of a river’s health

Ironically, the Gangetic Dolphins were probably the first animals in the world to have been accorded protection. During the rule of Emperor Ashoka in third century BC, the dolphins were considered sacred and specially protected.

Locally, the dolphins are called ‘Susu’, because of the breathing sound that they make. Ecologists consider the Gangetic Dolphin an extremely useful animal for monitoring the river. These animals act as an indicator of health for the ecosystem of the river.

Being at the top of the food chain, its presence in good numbers signifies a rich biodiversity within the river system. The Gangetic Dolphin is among the four freshwater dolphins found in the world - the other three are the Baiji found in the Yangtze river in China, the Bhulan of the Indus in Pakistan and the Boto of the Amazon River in Latin America.

Like any other dolphin, the Gangetic Dolphin looks very beautiful. Like the other river dolphins, they too have long, pointed noses. The teeth are visible in both the upper and lower jaws even when the mouth is closed. The body is brown in colour and stocky at the middle. They have only a small triangular lump in the place of a dorsal fin. The flippers and tail are thin and large in relation to the body size.

The Gangetic Dolphins are considered to be blind because their eyes do not have crystalline eye lens. But they may still be able to detect the intensity and direction of light. Also, they can still effectively navigate and hunt in the murky waters of the Ganga by using using echolocation, which is similar to the use of sonars in submarines.

Their rapid decline in numbers in the last few decades testifies to the development and conservation policies of the country. Even though the dolphins have been declared ‘highly endangered’ in Schedule I under the Wildlife Protection Act of 1972, their numbers have plummeted. This is because aquatic habitats like rivers and lakes have received less or no importance as compared to terrestrial ecosystems like the evergreen and decidous forests in India.

Development, at what cost?

Extensive damming of the Ganga and Brahmaputra Rivers for electricity and irrigation have contributed largely to the decline in their population. Damming of the rivers has led to segregation of populations resulting in a small genetic pool in which the dolphins can breed.

They have also been impacted adversely by human activities in these rivers.

Entanglement in fishing nets can cause a significant damage to the remaining population. Some individuals are killed each year for their oil and meat which is used as an aphrodisiac and bait for catfish. It is also suspected that high levels of pollution of these rivers are contributing to their decline in numbers.

A recent announcement by the Ministry of Environment and Forests to accord the Gangetic Dolphins the status of National Aquatic Animal raises hope of survival for this highly endangered mammal and also the highly polluted River Ganga. This new status is likely to raise the public awareness and support for its conservation and protection.
However, the main issue which needs to be addressed effectively is the revival and conservation of river ecosystems that have been neglected for several decades. Or else, Gangetic Dolphins will merely become another symbol for campaigns such as ‘Save the tiger’!

Conversely, a successful conservation story of the Gangetic Dolphins will mean that we have achieved water security for the vast number of people dependent on the Ganga and the Brahmaputra.

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(Published 31 May 2010, 12:36 IST)

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