Conservation group WWF announced Tuesday that 10 new Irrawaddy dolphin calves were sighted this year in the section of Mekong River that runs through Cambodia, raising hope of saving the species from local extinction.

It said the birth of the calves — seven in Kratie province and three in Stung Treng province — are a "great encouragement and reward" of its decade-long collaborative efforts with Cambodia's Fisheries Administration to protect the critically endangered species.

Irrawaddy dolphins are confined to a few isolated populations in South and Southeast Asia, all of them at risk of extinction.

Conservationists believed that no more than 80 survive in the Cambodian section of the Mekong River.

Last year, the species was declared functionally extinct in neighboring Laos.

The dolphins are primarily threatened by rampant illegal and destructive fishing practices such as gill nets, poisoning, electroshock and explosive fishing devices. Other threats include hydropower dam construction, decreasing water levels and collisions with boats.