The Ganges sus, formerly quite abundant throughout its range, is now believed to number only 4,000-5,000 individuals; it is possible that there are as few as 40 remaining in Nepal. The construction of a large dam at Kaptai on the Karnaphuli River has prevented the migration of the dolphin to the adjacent river system of the Brahmaputra and Ganges. All the Ganges susus above the dam have disappeared, and those below it appear to be declining.
Every year 2,500 tonnes of pesticide and 1.2 million tonnes of fertilizers are used in the vicinity of the Ganges River. It receives the discharges from a wide variety of sources, including sugar mills, tanneries and chemical plants, as well as from about 700 towns and cities along its banks. The Ganges Basin is the home of more than 220 million people, 37 per cent of the total population of India.
In Nepal, the species' habitat is being degraded by logging, road building, irrigation and the mining of gravel and rock along the river banks and in the river beds themselves.
The species' close cousin, the Indus susu, has declined to a population of around 500. It is now extinct in parts of its former range. Like its close relative, the Indus susu has been divided into several populations by a series of irrigation dams. Three of the six populations may be on the verge of extinction; one may number only 2 or 3 individuals.
An Indus Dolphin Reserve was established in 1974 on the 170-km (105-mile) stretch of the Indus between the Guddu and Sukkur Barrages by the governments of Sind Province.
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