A wounded female Irrawaddy dolphin was found dead in the Mekong River in Kampong Cham on Saturday.

The 130-kilogram dolphin was discovered by residents in Kampong Siem town, significantly south of the species’ protected area, according to fishery administration officials.

Authorities have not yet determined the cause of death, though the dolphin was transferred to a fisheries office in Kratie for further examination.

“We saw that before the dolphin died, it drifted from further up the Mekong … and was found dead at the river bank with fishing net and a wound on its head,” said Phoung Tina, a deputy director of the Kampong Cham Fisheries Administration.

The Irrawaddy dolphin is considered critically endangered. A 2010 survey by the conservation NGO WWF estimated the population at between 78 and 91 dolphins.

The death of a female was a particular blow to the species’ breeding potential, said Gerry Ryan of WWF-Cambodia.