The endangered Indus river dolphin

from Reuters

June 7 (Reuters) - The 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.

A survey carried out in March this year showed their numbers in Pakistan had risen to 1,331 from about 1,100 in 2001, most of them concentrated in one small section of the river.

Here are some facts about the Indus river dolphin:

- The unique, blind dolphin is one of the world's four freshwater dolphin species, and one of its rarest mammals.

- The dolphins were once common throughout the Indus river system. Today they occur in only a fifth of their previous range, in small populations, fragmented by barrages built across the river since the 1930s.

- Most are confined to a 200-km (125-mile) stretch of the river between barrages in the north of Sindh province.

- They sometimes carry their young on their backs, above the surface of the water. Although Indus dolphins prefer deep water, they can live in water as shallow as 1 metre (3.3 feet) because of their ability to swim on their side.

- Grey-brown in colour, fully grown adults are 1.5 to 2.5 metres (4.9 to 8.2 feet) in length and weigh up to 90 kg (200 lb). Males are smaller than females.

- Maturing at about 10 years, they are estimated to have a life-span of at least 28 years.

- The dolphins are functionally blind, using tiny remnant eyes only to tell day from night. They rely on sonar to find fish, shrimp, and other prey in the murky depths.

- The World Conservation Union (IUCN) says the biggest threat to their survival has been the construction of dams and barrages that have fragmented the population and reduced the amount of available habitat. (Sources: Reuters; Whale and Dolphin Conservation Society (www.wdsc.org); World Wildlife Federation (www.wwfpak.org)