Fishermen living on the banks of the Mekong River in Cambodia have hit the headlines for catching the world’s biggest freshwater fish weighing 300 kg that took around a dozen men to haul to shore.

The 13-foot-long female stingray was released back into the Mekong after being electronically tagged to allow scientists to monitor her behaviour.

"This is very exciting news because it was the world's largest fish," said biologist Zeb Hogan, ex-host of the "Monster Fish" show on the National Geographic Channel and now part of a conservation project on the river.

"It is also exciting news because it means that this stretch of the Mekong is still healthy…. It is a sign of hope that these huge fish still live here."

The earlier record was held by a 293 kg giant catfish that was caught upstream in northern Thailand in 2005.

The Mekong is reported to have one of the most varied fish population in the world, but overfishing, pollution and saltwater intrusion have taken their toll.