Bangkok - Thai fishermen caught a 293kg catfish that may have been the world's largest freshwater fish, wildlife conservation groups said.
The Mekong giant catfish was netted by villagers in a remote part of northern Thailand, the World Wildlife Fund and the National Geographic Society said in a statement.
When wildlife officials caught wind of the catch they urged the villagers to release the adult male so that it could spawn, but it later died and was eaten, the groups said. They did not say when the massive fish was caught.
The fish was the heaviest recorded since Thai officials started tracking the species in 1981 and may be the largest freshwater fish ever discovered, the statement said.
"An astonishing find," researcher Zeb Hogan was quoted as saying. Hogan leads an international project funded by the groups to locate and study the world's largest freshwater fish species.
The catfish species has been declining, a phenomenon fishermen blame on dams and environmental damage along the Mekong River - home to more species of giant fish than any other river, the statement said.
The Mekong giant catfish - which shares the title of largest freshwater fish with a close relative, the dog-eating catfish - was listed as critically endangered in 2003 after research showed its numbers had fallen by at least 80 percent over the past 13 years.
"My study of giant freshwater fish is showing a clear and global pattern - the largest fish species are disappearing," Hogan said.
"By acting now, we can save animals like the Mekong giant catfish from extinction." - Sapa-AP