Scientists have warned against the decreasing number of river dolphins and said that the rising number of dams is posing serious threat to them.
According to a new study, the populations of the Indus river dolphins, which are endangered, are dropping in rivers due to the removal of water for irrigation and habitat fragmentation.
Indus River Dolphin is an endangered freshwater dolphin, inhabiting in one of the most modified rivers worldwide.
It’s note worthy, the population of many freshwater marine mammals are getting endangered due to swiftly degrading of their habitats. Moreover, conservation of remaining habitats has also been ignored.
Gill Braulik, of the Wildlife Conservation Society, carried a study on dolphins along with other researchers from the University of St. Andrews.
Origin of Dolphin
Dolphins, who are man’s best buddy, are believed to have originated in the ancient Tethys Sea.
But Tethys Sea dried up 50 million years ago. According to the World Wildlife Fund, the dolphins were forced to adapt to rivers for their survival.
It’s noteworthy that about 1,100 dolphins are remaining today in the lower parts of the Indus River in Pakistan. These dolphins are mostly confined to its 750-mile stretch.
For the study, the researchers collected historical range data and information on these endangered species. They collected fisher interviews to better comprehend the timing pattern of drop in the Indus River Dolphin.
In a bid to understand the reasons behind their decline, the researchers tried to collect info on the construction date of the nearest dam, its dry season river discharge, length of river section and its distance from the edge of the former range.
The researchers found that the historical range of the Indus dolphin was fragmented into 17 river sections by diversion dams.
Shockingly, dolphins disappeared from almost ten river sections. Researchers mainly blamed the low dry-season river discharge, due to irrigation at diversion dams, responsible for their declining numbers and decreasing habitat.
“This important study shows that it is river habitat fragmentation by dams, and removal of river water for irrigation that has caused the massive range decline of the Indus River freshwater dolphin,” Braulik said in a statement.
Braulik further said, “This increased understanding of species decline in fragmented river systems is especially important because hundreds of new dams and water developments are planned or are under construction in many of the world’s rivers and large losses of aquatic biodiversity can be expected.”
The findings of the study were published in the journal PLOS ONE.