A female Irrawaddy dolphin and its baby were found dead yesterday morning in Kratie province’s Chet Borei district, though the World Wildlife Fund (WWF) said the cause of death is still unknown.

Un Chakrey, an official at WWF, said the mother dolphin and its baby were found side by side in the river near the district’s Bos Leav commune.

“We do not know the cause of death. It could have been a natural death during childbirth,” Chakrey said, though he did not rule out the possibility that the dolphins had been killed.

“They could have been trapped in the net of local fishers.”

Although Irrawaddy dolphins are not purposefully exploited, they are often killed accidentally by fishermen who string nets illegally in the protected waters where they live.

The mother dolphin was 120 kilograms and 220 centimetres long. Her baby was just 1 kilogram and 44 centimetres long. Chakrey said the bodies will be frozen for further investigation.

This is the fifth Irrawaddy dolphin death this year. The WWF estimates that there are only about 80 left in the Mekong.