The last known freshwater Irrawaddy dolphin on a stretch of the Mekong River in northeastern Cambodia has died, apparently after getting tangled in a fishing net, wildlife officials said Wednesday.
The aquatic mammal was found dead Tuesday on a riverbank in Stung Treng province near the border with Laos, Cambodia's Fisheries Conservation Department announced on its Facebook page.
The Irrawaddy dolphin, also known as the Mekong River dolphin, is classified as an endangered species by the International Union for Conservation of Nature. Other groups of these dolphins are still to be found farther downstream in Cambodia and in two other freshwater rivers — Myanmar’s Irrawaddy and Indonesia’s Mahakam on the island of Borneo.
The first census of Irrawaddy dolphins in Cambodia in 1997 estimated their total population was about 200. In 2020, the population was estimated to have fallen to 89, almost all in the group that still exists downstream from Stung Treng.
“The remaining population of ‘critically endangered’ river dolphins in the Cambodia section of the Mekong is now stable, whilst still facing serious challenges,” said a statement from Lan Mercado, Asia-Pacific director of the World Wildlife Fund. “This latest river dolphin death highlights how vulnerable these and other species remain.”
The tail of the dolphin that died Tuesday was seen tangled in a fishing net about a week earlier, the Cambodian state news agency AKP reported. It said the dolphin was unable to swim properly after that and died due to its injury and inability to catch its usual prey for nourishment.
The World Wildlife Fund said the 25-year-old male dolphin, 2.6 meters (8.5 feet) long and weighing 110 kilograms (242 pounds), is believed to have died three days before his body was found.
In addition to being entangled in fishing nets, the species is also threatened by pollution, according to Cambodia's Fisheries Administration and other conservationists.
In recent years, risks have also increased due to climate change and waters made shallow by the construction of upstream dams, both of which decrease water flow and the number of other aquatic species that the dolphins eat.