Progress protecting Mekong River dolphins undermined by proposed dams

Somany Phay, Frances Gulland, and H.E. Srun Limsong, Deputy Director General of the Fisheries Administration, Royal Government of Cambodia. Photo Credit: Peter Thomas

In January 2017 an international workshop on the Critically Endangered freshwater population of dolphins (Orcaella brevirostris) in the Mekong River was held in Kratie, Cambodia [click here to read report]. This was the fourth such workshop convened by the World Wide Fund for Nature (WWF) – Cambodia and the Cambodian Fisheries Administration, all of them organized and conducted in collaboration with the CSG and the U.S. Marine Mammal Commission [click here for more details].

At this workshop the external advisory group concluded that significant progress had been made on implementing most of the recommendations from the 2014 workshop, thanks to the commitment of the WWF-Cambodia team, the Fisheries Administration, the River Guards and the local community. The River Guards have worked hard to confiscate gillnets in the core dolphin zones and the consequent reduction in entanglement risk may have been a significant factor contributing to the recent increase in calf survival. The River Guards nevertheless continue to face a number of obstacles and gillnetting remains a serious threat.

River guards burning confiscated gillnets. Photo credit: Peter Thomas

Unfortunately, the threat of hydropower development, addressed in detail at the 2014 workshop, is now a reality for this population. Since the construction of the Don Sahong dam near the Laos/Cambodia border began in 2014, a local subpopulation of dolphins has declined from five to only three individual dolphins and there is now virtually no hope for its persistence. Progress on slowing the decline of the Mekong dolphin population, which currently numbers only about 80 individuals, could be completely nullified by construction of the proposed Sambor and Stung Treng hydropower dams. If built, these dams will eliminate or transform most of the dolphins’ remaining riverine habitat. A Memorandum of Understanding was signed recently between the Cambodia government and a private company to carry out feasibility studies on the two new dams.

Construction of the Don Sahong Dam on the Mekong River in Laos. Photo Credit: Peter Thomas

Other populations of Irrawaddy dolphins were also discussed, including the Critically Endangered Mahakam (Indonesia) and Ayeyarwady (Myanmar) freshwater ones as well as those in the estuaries and mangrove channels of Bangladesh.