Rare Dolphin Thrives in Small Part of Indus River
By Robert Birsel
ISLAMABAD — The highly endangered Indus river dolphin has dramatically increased in numbers in a small section of the Indus in Pakistan but the animals remain very rare and in grave danger, a scientist said on Wednesday.
The unique, blind dolphin is one of the world’s four freshwater dolphin species, and one of its rarest mammals.
While the animals once thrived from the lower Indus up to the foothills of the Himalayas, its range has shrunk to just 20 percent of that, British dolphin expert Gill Braulik told a news conference.
Barrages built across the Indus since the 1930s to collect and divert water for agriculture have reduced the dolphin population to small, isolated pockets.
According to a survey carried out in March this year, the number of the dolphins in Pakistan has risen to 1,331 from about 1,100 in 2001, most of them concentrated in one small section of the river.
Most of the dolphins recorded in the survey, about 1,200 of them, were confined to a 200-km (125-mile) stretch of the river between barrages in the north of Sindh province.
The dolphin population in that stretch had increased almost 65 percent since the 2001 survey, said Braulik, a scientist with the U.N.- and government-backed Pakistan Wetlands Programme.
“There was a dramatic increase in abundance between Guddu and Sukkur,” Braulik said, referring to the stretch of river.
“This was extremely unexpected and is very encouraging news for the species,” she said.
The number of dolphins in four other stretches of the river covered in the survey ranged from just one to 82, she said.
Braulik said it was unclear why numbers had increased so dramatically in the river between Guddu and Sukkur but a ban on hunting might have played a part.
The animals might be slipping through barrages further up stream when they are opened for a day or two each year, and massing in that stretch of the river, she said.
That part of the river was also the deepest found in the survey and the animals are known to like deep water, she said.
But the concentration of the animals in that one small section of the river made the species extremely vulnerable.
With millions of people and extensive industry upstream of that section of the river, the animals would be in grave danger in the event of an industrial spill.
“It remains one of the most endangered dolphins in the world despite the encouraging results of this survey,” she said.
Feeding on crustaceans and fish in the turbid waters of the Indus, the animal has only tiny remnant eyes and is functionally blind. It relies on sonar to find its food in the murky depths.