The previous record for a freshwater fish was a 293-kilogram (646-pound) Mekong giant catfish, discovered in Thailand in 2005, the group said.

The stingray was snagged by a local fisherman south of Stung Treng in northeastern Cambodia. The fisherman alerted a nearby team of scientists from the Wonders of the Mekong project, which has publicized its conservation work in communities along the river.