Mekong river dolphins on verge of extinction: WWF

TOKYO: Dolphins living in parts of the Mekong River between Cambodia and Laos are on the brink of extinction due to pollution, international conservationist group WWF warned in a report.

Inhabiting a 190-kilometer stretch of the river, the Irrawaddy dolphin population has suffered 88 deaths since 2003, of which 58 were calves under 2 weeks old, bringing the latest population to an estimated 64 to 76 members, the World Wide Fund for Nature said.

WWF researchers found high toxic levels of pesticides such as DDT and environmental contaminants such as PCBs alongwith mercury in an analysis of 21 dead dolphins retrieved between 2004 and 2006.

Of the 11 dead dolphins recovered in 2007, 10 died of tumors and while rest were infected with bacteria, WWF found.

A bacterial disease was identified to be the cause of the calf deaths but it "would not be fatal unless the dolphin's immune systems were suppressed, as in these case, by environmental contaminants," report author and veterinarian Verne Dove with WWF Cambodia was quoted as saying.

Another factor identified for the dolphin deaths was their limited genetic diversity due to inbreeding in an isolated habitat.