Dolphins

Why in News?

• FSI surveys reveal that sizeable number of dolphins on the east coast along Indian EEZ.

For Prelims: Types of Dolphins, Fisheries survey of India

• In all 2703 dolphins and 4 whales have been sighted in marine mamal stock assesment survey conducted in coast covering Andhra Pradesh, Orissa, West Bengal.

3 Type of Dolphins in India

1. Gangetic Dolphin

• The Gangetic dolphin, also called the Ganges river dolphin, is a freshwater dolphin found in the Ganges-Brahmaputra-Meghna and Karnaphuli-Sangu river systems in Nepal, India, and Bangladesh.
  • Currently, only an estimated 3,500-5,000 Gangetic dolphins remain. Due to declining numbers and population fragmentation, the species is listed as Endangered by the IUCN Red List.
• The Gangetic dolphin has a long thin snout and rounded belly. Their bodies are stocky, and they have large flippers compared to oceanic dolphins.
  • Adults have smooth, hairless skin that is gray-brown in color. The females are bigger than males, growing over 2 meters long and weighing up to 170kg, compared to 2.12m and 150kg for males.

2. Indus River Dolphin

• The Indus River dolphin is a freshwater dolphin that lives only in the lower parts of the Indus River in Pakistan and the Beas River in Punjab, India.
• With an estimated population between 1,200-1,800, Indus River dolphins are classified as Endangered by the IUCN Red List.
  • They continue to face threats from human activities like fishing and development projects.
• Indus River dolphins have a distinctive stocky body shape with a rounded forehead called a “melon”. They grow around 2 meters long and weigh 150-200kg. Their skin color is mostly gray on the back and pale pinkish or white on the underside.

3. Irrawaddy Dolphins

• The Irrawaddy dolphin (Orcaella brevirostris) is a unique freshwater dolphin found in parts of South and Southeast Asia.
  • Unlike most dolphins that live in the ocean, Irrawaddy dolphins are adapted to river habitats like the Ayeyarwady in Myanmar, Mekong in Cambodia and Chilika lake in Odisha.
• Irrawaddy dolphins are classified as Endangered on the IUCN Red List. Once more widespread, their distribution is now patchy and limited to small pockets across their range. 
• Irrawaddy dolphins have short round heads without a beak, giving them expressive-looking faces. Their flexible necks allow greater head movement while echolocating.