Ganges River Dolphins
Indian Government has notified the Ganges River Dolphin (Platanista gangetica gangetica) as India’s National Aquatic Animal. It is also known as Susu because of the sound it produces when breathing. The Total population of Ganges River Dolphin is estimated to be around 2000 and they inhabit the Ganges-Brahmaputra-Meghna and Karnaphuli-Sangu river systems of Nepal, India and Bangladesh. These dolphins are found in Assam, Uttar Pradesh, Madhya Pradesh, Rajasthan, Bihar, Jharkhand and West Bengal (7 states ) and ideal habitats are in the Ganga, Chambal, Ghaghra, Gandak, Sone, Kosi, the Brahmaputra and Kulsi rivers. Ganges River Dolphin is placed under “Endangered Category” in the IUCN Red List. It lives in one of the world’s most densely populated areas, and is threatened by removal of river water and siltation arising from deforestation, pollution and entanglement in fisheries nets. They have been poached over for their oil. The habitat degradation due to declining flow, heavy siltation and construction of barrages causing physical barrier for this migratory species is also one of the reasons behind decline of their numbers. In October 2015, the West Bengal government decided to establish India’s first Dolphin Community Reserve in the state at Hooghly River between Malda and Sundarbans.
True freshwater river dolphins
There are only four true freshwater river dolphins found around the world viz. Ganges River Dolphin, Indus River Dolphin, Amazon River Dolphin and Yagtze River Dolphins. Further, the Irrawady river dolphins can survive in both fresh and marine waters.
Indus River Dolphin (Platanista minor minor) is found in Indus river in Pakistan and also in Beas and Sutlej rivers in India. Both Ganges River Dolphin and Indus river Dolphin are now taxonomically considered one species since 1998.
The Amazon River Dolphins are is found in plenty number in Amazon river. The Yangtze river dolphins have not been seen in last one decade and it is believed that they have gone extinct. The Irrawady river dolphins, which can survive both in fresh water and marine water are found in Myanmar, Indonesia and the Mekong river delta in south-east Asia. Some of the Irrawady River Dolphins are also found in Bangladesh and India’s Chilka Lake in Odisha.