Gangetic Dolphin Annual Census | 11 Oct 2019

Recently, the annual Ganges river Dolphin census was undertaken by the World Wide Fund for Nature- India in collaboration with the Uttar Pradesh Forest Department along about 250 km. long riverine stretch of Upper Ganga river basin between Hastinapur Wildlife Sanctuary and Narora Ramsar site.

  • This year the tandem boat survey method replaced the previous years’ direct counting method in order to provide a more accurate count of the endangered species.
    • In the ‘tandem boat survey’ method, the officials use two inflated boats which move in tandem to count the dolphins. After collating the data, statistical tools are employed to arrive at the final count.
  • In 2015 census their count was 22, and since then the number has been stable in the last few years. This year, there is an expected rise in their number.

Ganga River Dolphin (Platanista Gangetica)

  • The Ganges river dolphin is found in parts of the Ganges-Meghna-Brahmaputra and Karnaphuli-Sangu river systems in India, Nepal, and Bangladesh.
  • The Gangetic river dolphin is India's national aquatic animal and is popularly known as ‘Susu’.
  • It is among the four freshwater dolphins in the world- the other three are:
    • The ‘Baiji’ now likely extinct from the Yangtze River in China,
    • The ‘Bhulan’ of the Indus in Pakistan, and
    • The ‘Boto’ of the Amazon River in Latin America.
    • These four species live only in rivers and lakes.
  • Its presence indicates the health of the riverine ecosystem.

Threats

  • Pollution: It faces a number of threats such as dumping of single-use plastics in water bodies, industrial pollution, fishing.
  • Restrictive Flow of Water: The increase in the number of barrages and dams is also affecting their growth as such structures impede the flow of water.
  • Poaching: Dolphins are also poached for their flesh, fat, and oil, which is used as a prey to catch fish, as an ointment and as a supposed aphrodisiac.
  • Shipping & Dredging: It is also called a blind dolphin because it doesn’t have an eye lens and uses echolocation to navigate and hunt.
    • Like bats, they produce high-frequency sounds which helps them to detect objects when the sound waves bounce off them.
    • Due to their dependence on echolocation, the Gangetic dolphins also suffer from the noise pollution created by large ship propellers, and by dredging.

Protection Status

  • IUCN Status: Endangered
  • It is listed on CITES Appendix-I.
  • It is classified under Schedule 1, Wildlife (Protection) Act, 1972 providing absolute protection as offences under these are prescribed the highest penalties.
  • Vikramshila Gangetic Dolphin Sanctuary (VGDS) in Bihar’s Bhagalpur district is India’s only sanctuary for its national aquatic animal.

Source: TH