Question: Recently a survey was conducted by the Cetacean Specialist Group of the International Union for Conservation of Nature (IUCN) on Dolphin number.The survey showed drop in Dolphin number in which river?
(a) Gandak
(b) Ghaghara
(c) Ganga
(d) Brahmaputra
Answer: (a)
Related facts:
- A count of the Ganges River Dolphin (Platanista gangetica) in two rivers of Bihar, Gandak and Ghaghara has revealed the presence of 280 dolphins.
- The number of dolphins recorded in a 324-km stretch of river Gandak were 155, a drop from 257 dolphins in 2009-10. In the 99-km stretch of river Ghaghara in Bihar the survey showed the presence of 125 dolphins.
- The estimation was done following the direct count method recommended by the Cetacean Specialist Group of the International Union for Conservation of Nature.
- Gandak is a regulated river due construction of river barrage on the Indo-Nepal border and thus the river depth is low, while the Ghaghara has deeper stretches.
- Ganges river dolphins usually prefer a depth of more than 2 metres and diversity in the river channels.
- Construction of National Waterway 37 is likely to pose a major threat to the population of Ganges river dolphin. Other threats include regulated discharge from Gandak Barrage, electrofishing (discharging electric current to kill fish) and mosquito-net fishing.
- The river system of Bihar, which includes Ganga and its other tributaries, are estimated to contain half of the population of Ganges river dolphin in the country.
Achyutanand Pandey