Fisherman in Cambodia Catches Largest Freshwater Fish Ever Hooked

A fisherman in northern Cambodia had captured a 661-pound fish, measuring about 13 feet in length, near a remote island on the Mekong River in the Stung Treng area.

The 42-year-old fisherman named Moul Thun had accidentally hooked the giant fish near Koh Preah island in the Mekong River in northern Cambodia. A team of scientists from the Wonders of Mekong research project identified the catch as a giant stingray (Urogymnus polylepis) which they said they know very "relatively little" about. It was believed to be the world's largest freshwater fish ever caught hooked in Cambodia, NBC News reported.

The research group helped tag, measure and weigh the ray before releasing it back into the river. The tag will allow researchers to track its movement and hopefully learn more about its species' behavior in the Mekong.

The fish was believed to be of good health and will expectedly survive in the water.

What We Know about the Giant Freshwater Fish

"You have a fish that's now the record holder for the world's largest freshwater fish, and we know little about it," says Zeb Hogan, a fish biologist at the University of Nevada.

Fish experts believe that giant freshwater stingray, such as this one in Cambodia's Mekong River, may be the largest freshwater species on Earth, according to the National Geographic.

However, they are also "cloaked with mystery", as very little are known about them. No one is sure how many of them are left, which habitats they prefer, or even if they ever venture into the ocean, where their more commonly known relatives live, the channel said.

It is a part of the research team's project to track the migratory fish by installing underwater receivers in the river.

"It's a particularly healthy stretch of the river with a lot of deep pools - pools up to 90 meters deep," said Hogan, who also hosts the National Geographic's "Monster Fish" television series. "We started focusing on this area as a stretch of river that's particularly important for biodiversity and fisheries, and as a last refuge for these big species."

Little is known about the giant fish, Hogan said, describing the creature having a mouth about "the size of a banana" with no teeth, but with "gripping pads" used to crush prey such as shrimps, mollusks and small fish.

Potential Pupping Ground for the Giant Fish

Fishermen have reported three catches of female stingrays so far in the area during the past two months, which means for scientists that the site could be an important seasonal gathering site for giant freshwater stingrays, "and might serve as a pupping ground for young", according to Hogan.

The tag and track in the river should help researchers etter understand fish migrations and local habitat in the upper Cambodian Mekong.

"There's potential for hydropower development right where these stingrays were caught," Hogan said. "We want to understand the importance of this area before there's development, potentially in an unsustainable way."

The Cambodian government has also expressed its interest in developing a conservation plan for the giant freshwater rays.