Irrawaddy Dolphin
Patchy distribution for a Critically Endangered species
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Irrawaddy Dolphins on Brink of Extinction
The critically endangered Irrawaddy dolphin population in the Mekong River numbers just 85. Calf survival is also very low. Read more
Common Name: Irrawaddy dolphin, snubfin dolphin ; orcelle (Fr); delfín de Irrawaddy(Sp)
Scientific Name: Orcaella brevirostris
Location: South-East Asia
Population: 85 individuals
Background
The species is patchily distributed in South-East Asia, and is primarily found in estuaries and mangrove areas, with freshwater populations occurring in river systems.
The Mahakam river (Kalimantan, Indonesian Borneo) population of Irrawaddy dolphins is severely threatened by fisheries bycatch and habitat degradation, and may number as few as 34 animals. The Mahakam subspecies is listed as Critically Endangered on the IUCN Redlist.
Surveys conducted in 2001 estimated that the Malampaya Sound population in the Philippines consists of just 77 individuals, confined to a small area in the inner sound, and is the only known population of this species in the country.The Malampaya Sound subspecies is listed as Critically Endangered on the IUCN Redlist.
During 2001 there were reports that as many as five animals from this population were killed incidentally in fishing operations, indicating that the Irrawaddy dolphins of Malampaya Sound are in immediate danger of extinction due to low numbers, limited range, and high mortality.
Physical Description
The Irrawaddy dolphin is identified by a bulging forehead, a short beak, and 12-19 teeth on each side of each jaw. The pectoral fin is broadly triangular. There is a small dorsal fin, on the posterior end of the back.
When diving, this dolphin breathes at intervals of 70-150 seconds; the head appears first and then disappears, and then the back emerges, but the tail is rarely seen.
Size
Head and body length is 180-275 cm.
Colour
Irrawaddy dophins are slaty blue to slaty gray throughout, with the underparts slightly paler.
Habitat
Biogeographic realm
Indo-Malayan
Range States
Australia, Papua New Guinea, Indonesia, India, Thailand, Myanmar, Laos, Vietnam, Philippines
Geographical Location
South-East Asia
Interesting Facts
Reports from the 1970s show that the fishermen of Burma attract the Irrawaddy dolphin by tapping the sides of their boats with oars. By swimming around the boat, the dolphin brings the fish into nets, and the fishermen share their catch with it.
