Karnali dolphins on verge of extinction

- PRAGATI SHAHI, Kathmandu
Karnali dolphins on verge of extinction

Apr 13, 2012-

The Ganges River Dolphin, locally known as ‘Susu’, faces an extinction threat unless the authorities concerned devise and implement stringent actions to protect these freshwater mammals in the Karnali River System.

A new field-based study conducted by a team of young researchers sighted only four dolphins in the Karnali river and its tributaries Mohana and Geruwa in the country. Dolphins are listed as critically endangered species, the highest level of threat under the list provided by the International Union for the Conservation of Nature (IUCN).

Earlier, a study conducted by the WWF-Nepal in 2005-2006 in the Karnali river and its tributaries recorded around 20 dolphins while the number was estimated to be above 100 a few decades ago. There has been little study by the government or concerned conservation partners, including researchers, on river dolphins in the country. The dolphins are also believed to exist in Koshi, Narayani and Mahakali rivers.

The findings of a three-month study on the hydro-ecological factors affecting the habitat and distribution of dolphins undertaken by Sambhu Paudel, a Master-level student, and supported by Gopal Khanal, a Bachelor-level student at the Institute of Forestry, Pokhara, show that these freshwater dolphins may become extinct in near future unless proper conservation actions are initiated at the earliest. The study was carried out in two phases this winter and will again be conducted in monsoon.

“There is a marked depletion of prey availability in winter due to intensive fishing, land use change and habitat fragmentation in both the river systems,” said Paudel. Meanwhile, there has not been a record of sightings of gharials, one of the top predators of aquatic system in the Karnali river. This clearly suggests that the number of fish is sharply declining in the rivers in recent years. According to the researchers, among confluence (meeting point of two rivers), deep pool (long/straight channel of part of river), meandering (zigzag part of the river)—the three types of habitat identified for the assessment, the confluence was found biologically rich and productive. This is the first scientific research carried out on dolphins by using the acoustic sensor, which gives a realistic number of dolphins in the country, said Khanal. The use of acoustic sensor to determine the number of dolphins is reportedly being used in the Ganges in India by scientists from the Zoological Society of London. “We believe this research will act as a touchstone for preparing action plan for dolphin conservation in Nepal, an urgent task to save the mammals,” said Paudel.

Published: 14-04-2012 07:56

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