While deaths of the Mekong River's critically endangered Irrawaddy dolphin have been decreasing for years, government officials and conservationists warned yesterday that Laos’s controversial Don Sahong hydropower dam could hinder efforts to protect the species.

Phay Somany, an administration official at the Ministry of Agriculture’s Fisheries Department, said the annual average number of deaths of the Mekong dolphin has dropped from 11 to six over the past four years.

“The latest death was caused by old age,” Somany said.

But, he added, in addition to threats including fishing and diseases, the construction of the 260-megawatt dam could put the species in jeopardy.

“We are worrying about effect of the Don Sahong dam construction. It is a new threat facing the dolphins and it is very controversial,” Somany said.

“When the construction takes place, the effect [on the dolphins] occurs when [builders] blow up the rocks. [The dam] will influence fish movement and lead to a loss of habitat through the irregular and unsustainable mud flow,” he added.

Somany’s comments came after around 200 villagers, government officials and activists from WWF gathered in Kratie province yesterday morning to mark International Freshwater Dolphin Day.

Chhit Sam Ath, country director of WWF-Cambodia, said the event was aimed at drawing attention to the dangers facing the Mekong dolphin.

“Dolphins are culturally, economically, and ecologically vital,” Sam Ath said.

Sam Ath said that while only 85 Mekong dolphins are estimated to be left in Kratie and Stung Treng’s parts of Mekong River, he explained that “education, promotion, legal implementation and conservation activities” were working.

So far this year, four dolphins have died, while seven calves have been born, he said.