PHNOM PENH (Reuters Life!) - Toxic waste in the Mekong River is a factor pushing an endangered dolphin species to extinction, the WWF warned on Thursday, estimating there were less than 80 left in a stretch of water between Cambodia and Laos.
Conservation group the World Wildlife for Nature (WWF) said high levels of mercury and other pollutants had caused the deaths of 88 Mekong River Irrawaddy dolphins since 2003, over 60 percent of them calves under two weeks old.
Bacterial disease killed many of the calves, it said.
"This disease would not be fatal unless the dolphin's immune systems were suppressed, as they were in these cases, by environmental contaminants," said Verne Dove, a veterinarian with WWF Cambodia, in a statement.
"Pollution in the Mekong River has pushed the local population of Irrawaddy dolphins to the brink of extinction," the conservation group said, estimating the number left in the 190 km (118 mile) stretch of the Mekong at between 64 and 76.
The WWF said limited genetic diversity due to inbreeding was another factor in the deaths of the Mekong dolphins, which were isolated from other members of the species.
However, one Cambodian specialist, Touch Seang Tana, who heads a group called Mekong River Dolphins Conservation, denied the animal was in danger of extinction and estimated there were 150 in Cambodia.
"How come the dolphin is on the brink of extinction when the animals give birth to more than 10 calves a year?" Seang Tana told Reuters.
He said an estimated 1,000 lived in Asia, including in India, Myanmar and Thailand.
The Mekong River Irrawaddy dolphin is listed as a critically endangered species by the International Union for Conservation of Nature.
The WWF researchers also warned that pollutants found in the Mekong water could affect the health of millions of humans who rely on resources from the river.
The Mekong produces an estimated 2.5 million tons of fish per year, with a value of at least US$2 billion, making it the world's largest inland fishery, the WWF said.
Reporting by Ek Madra; Editing by Miral Fahmy