The world’s largest recorded freshwater fish, a giant stingray, has been caught in the Mekong River in Cambodia, according to scientists.
The stingray, captured on 13 June, measured almost four metres from snout to tail and weighed just under 300kg, according to a statement on Monday by Wonders of the Mekong, a joint Cambodian-US research project.
The previous record for a freshwater fish was a 293kg Mekong giant catfish discovered in Thailand in 2005, the group said.
The stingray was snagged by a local fisher south of Stung Treng in north-east Cambodia. The fisher alerted a team of scientists from the Wonders of the Mekong project, which has publicised its conservation work in communities along the river.
The scientists arrived within hours of getting a post-midnight call with the news, and were amazed at what they saw. “Yeah, when you see a fish this size, especially in freshwater, it is hard to comprehend, so I think all of our team was stunned,” said the Wonders of the Mekong leader, Zeb Hogan.
“The fact that the fish can still get this big is a hopeful sign for the Mekong River,” he said, noting that the waterway faces many environmental challenges.
The Mekong runs through China, Myanmar, Laos, Thailand, Cambodia and Vietnam, and is home to several species of giant freshwater fish, but environmental pressures are rising. Scientists fear that a major programme of dam building in recent years may be seriously disrupting spawning grounds.
A tagging device was inserted near the fish’s tail that will send tracking information for the next year, providing unprecedented data on giant stingray behaviour in Cambodia.
“The giant stingray is a very poorly understood fish. Its name, even its scientific name, has changed several times in the last 20 years,” Hogan said. “It’s found throughout south-east Asia, but we have almost no information about it. We don’t know about its life history. We don’t know about its ecology, about its migration patterns.”
Researchers say it’s the fourth giant stingray reported in the same area in the past two months, all of them females. They think this may be a spawning hotspot for the species.
Local residents nicknamed the stingray “Boramy” – meaning “full moon” – because of its round shape and because the moon was on the horizon when it was freed on 14 June. In addition to the honour of having caught the record-breaker, the lucky fisher was compensated at market rate, meaning he received a payment of about $600.
“Big fish globally are endangered. They’re high-value species. They take a long time to mature. So if they’re fished before they mature, they don’t have a chance to reproduce,” Hogan said.
“A lot of these big fish are migratory, so they need large areas to survive. They’re impacted by things like habitat fragmentation from dams [and are] obviously impacted by overfishing. So about 70% of giant freshwater fish globally are threatened with extinction, and all of the Mekong species.”