Number of freshwater dolphins doubles in two decades: StudySigns are encouraging for the conservation of Gangetic River Dolphins as their number has gone up from 14 in 1993 to 28 in 2014 in the three major riversystems in the country
Saptakoshi, Karnali and Narayani river systems have recorded the presence of 14, 12 and 2 of these freshwater mammals respectively. The first ever survey on dolphins conducted after two decades found that the seven-kilometre stretch extending downstream from Koshi Barrage towards Nepal-India border recorded the highest density of dolphins in the country, followed by Karnali and Narayani. Likewise, the Mahakali river in the Far-Western region, where dolphins were seen in the previous studies, failed to record its presence.
In 1993, BD Smith and his team of researchers had conducted a study on the status of Ganges River dolphins in Nepal’s rivers and recorded a total of 14, with Karnali showing the highest number at 7, followed by Saptakoshi and Narayani at 5 and 2 respectively. Before and after Smith’s study, various research works on dolphins were carried out in the country but focused on individual rivers than finding the total number of the freshwater river dolphins throughout the country. According to Shambhu Paudel, assistant professor at the Kathmandu Forestry College, who conducted the one-year survey between August 2013 and July 2014, the studies on Dolphins till now were based on direct count and not included the missing animals in the river systems. “And this was the first time, we used both direct count and missing animals to bring their total number,” he said. Paudel added that unlike the rivers in neighbouring countries where dolphins are found, human pressure on river habitats, including excessive fishing and habitat degradation, is low in Nepal’s rivers except few places. In 2000, researcher duo Shanta Raj Jnwali and Ukesh Raj Bhuju had concluded that Karnali and Koshi were the only rivers in the country harbouring river dolphins. The sighting of blind dolphin in Narayani has disproved the conclusion.
“The study is important to provide benchmark for the future population comparisons and study,” Paudel said. The one-year study covered whole river systems and could be used as base line for further conservation actions and planning by researchers and policy makers, he said.
The study also revealed that during the pre-monsoon season, dolphins are found in abundance while the habitat becomes critical after monsoon (below lower threshold level). “Though the results are encouraging, the situation is still critical and needs adequate conservation planning for sustainable conservation of dolphins,” he said.