The largest freshwater fish in the world so far has been caught in Cambodia

The largest recorded freshwater fish in the world, the giant stingray, has been caught in the Mekong River in Cambodia, scientists from that country and the United States announced.

The fish, caught on June 13, measured nearly four meters from head to tail and weighed just under 300 kilograms, according to a statement from the joint Cambodia-American association.

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

The ray was caught 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.

Scientists arrived within hours of receiving the news and were amazed by what they saw, said "Miracles of the Mekong" scientist team leader Zeb Hogan.

"Yeah, when you see a fish this size, especially in fresh water, it's hard to comprehend, so I think our whole team was amazed," Hogan said.

Freshwater fish are defined as those that spend their entire lives in fresh water, as opposed to giant marine species such as bluefin tuna and marlin, or fish that migrate between fresh and salt water.

"The fact that the fish can still be this big is a sign of hope for the Mekong River," Hogan said and warned of the environmental problems the river is facing.

The Mekong River flows through China, Myanmar, Laos, Thailand, Cambodia and Vietnam. It is home to several species of giant freshwater fish, but pressures on the environment are growing.

In particular, scientists fear that the large dam-building program of recent years could seriously disrupt spawning grounds.

"Globally, big fish are threatened. They're a high-value species. They take a long time to mature. So if they're caught before they're mature, they don't have a chance to reproduce," Hogan said.

He added that about 70 percent of giant freshwater fish globally are threatened with extinction, as well as all Mekong species.

A team that rushed to the site inserted a tracking device near the tail of the mighty fish that will send information over the next year, providing data on the behavior of the giant stingray 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. We don't know much about its life history, ecology and migration patterns," Hogan said.

Researchers say it is the fourth giant stingray reported in the same area in the past two months, all of which have been females. They think this could be the focal point of the species.

Locals nicknamed the rye "Borami" or "full moon" because of its round shape and because the moon was on the horizon when it was released on June 14.