The World Wildlife Fund (WWF) warned Thursday that a dam that Laos plans to build across the Mekong River could threaten the existence of critically endangered Irrawaddy dolphins in downstream Cambodia.

"The Lao government's decision to forge ahead with the Don Sahong hydropower project in southern Laos, located just 1 km upstream of the core habitat for Mekong dolphins, could precipitate the extinction of the species from the Mekong River," the WWF said in a statement.

According to the WWF, the dam builders intend to excavate millions of tones of rock using explosives, creating strong sound waves that could potentially kill dolphins which have highly sensitive hearing structures.

"Plans to construct the Don Sahong dam in a channel immediately upstream from these dolphins will likely hasten their disappearance from the Mekong," said Chhith Sam Ath, WWF-Cambodia's Country Director.

"The dam's impacts on the dolphins probably cannot be mitigated, and certainly not through the limited and vague plans outlined in the project's environmental impact assessment,"he said.

The WWF urged Cambodian Prime Minister Hun Sen to call for a moratorium on the dam during the Mekong River Commission's Heads of State Summit in April.

Freshwater Irrawaddy dolphins are critically endangered in the Mekong River, where their numbers have dwindled to around 85 individuals restricted to a 190 km stretch of the Mekong River mainstream between southern Laos and northeast Cambodia, the WWF said. However, the Cambodian government estimated that the total population of Mekong river dolphins in the area is between 155 and 175 heads.

In August 2012, the Cambodian government approved a dolphin protection zone in a 180-km stretch along Mekong River from the border of Laos to Cambodia's Stung Treng and Kratie provinces.



The Mekong River Irrawaddy dolphin has been listed as critically endangered on the World Conservation Union Red List of Threatened Species since 2004.