Mekong River Dolphins Near ‘Brink of Extinction’

For the Mekong River dolphins, the water in which they are born, live and reproduce may be poison. Toxic levels of pesticides, environmental contaminants and mercury in the Lower Mekong, along with other factors, are bringing the Irrawaddy dolphins to the “brink of extinction,” a new report by the World Wildlife Fund (WWF) said.

According to the study, water pollution from unidentified sources has caused the deaths of at least 88 animals since 2003, with more than 60 percent of them being calves under two weeks old. According to scientists, water contaminants weakened the animals’ immune systems, making them more susceptible to infectious disease. Limited genetic diversity due to inbreeding might have also played a role, they noted.

“Necropsy analysis identified a bacterial disease as the cause of the calf deaths,” said Dr. Verne Dove, report author and veterinarian at WWF Cambodia. “The disease would not be fatal unless the dolphins’ immune systems were suppressed, as they were in these cases by environmental contaminants.”

The dolphins inhabit a stretch of the Mekong between Cambodia and Laos, but the water contaminants might have come from anywhere along the river, which flows through six countries in Southeast Asia and supplies water to more than 300 million people.

“A transboundary preventative health programme is urgently needed to manage the disease-affected animals in order to reduce the number of deaths each year,” said Seng Teak, country director of WWF Cambodia.

A sacred animal to both Khmer and Lao people, the Irrawaddy dolphin is listed as a highly endangered species by the International Union for Conservation of Nature. WWF estimates that the Mekong dolphins number between 64 and 76 members.

However, the head of the Mekong River Dolphins Conservation denied that the animal species is in danger.

“How come the dolphin is on the brink of extinction when animals give birth to more than 10 calves a year,” Seang Tana told Reuters. She estimated that there were about 150 Irrawaddy dolphins in Cambodia only.

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Sources: World Wildlife Fund, Reuters

Inset image by Jim Davidson, and reproduced under a creative commons license.