This undated photo provided by Chhut Chheana shows a researcher holding a giant salmon carp Aaptosyax grypus rediscovered in Cambodia. (Chhut Chheana/Wonders of the Mekong via AP)This undated photo provided by Chhut Chheana shows a researcher holding a giant salmon carp Aaptosyax grypus rediscovered in Cambodia. (Chhut Chheana/Wonders of the Mekong via AP)

Researchers say a large fish that was thought to have disappeared from Asia’s Mekong River has been seen in the waterway in recent years.

The fish is called a giant salmon carp. A recent study detailed the most recent sightings of the fish. The lead writer of that study said the fish was seen at least three times between 2020 and 2023.

The predatory fish can grow to more than one meter in length and has an identifiable yellow spot surrounding its large eyes.

The Mekong River is Southeast Asia’s longest river. It passes through China, Laos, Thailand, Myanmar, Cambodia and Vietnam. About 60 million people depend on the river for food and survival. It is also an important environment for numerous river creatures.

The leader of the research was Chheana Chhut. He is with the Inland Fisheries Research and Development Institute in Phnom Penh, Cambodia. “The giant salmon carp is like a symbol of the Mekong region,” Chheana recently told The Associated Press.

He was the co-writer with other researchers of a study announcing the findings in the publication Biological Conservation. Chheana said researchers had believed that the last confirmed sighting of the fish in the Mekong was in 2005.

This undated photo provided by Chhut Chheana shows a giant salmon carp, rediscovered in Cambodia. (Chhut Chheana/Wonders of the Mekong via AP)
This undated photo provided by Chhut Chheana shows a giant salmon carp, rediscovered in Cambodia. (Chhut Chheana/Wonders of the Mekong via AP)

But since 2017, biologists following the movements of migratory fish in Cambodia developed relationships with local fishing communities. They asked people in the communities to inform them of any unusual sightings.

That process led to the finding that three giant salmon carp were identified in the Mekong River and a neighboring waterway in Cambodia between 2020 and 2023.

Bunyeth Chan is a researcher at Cambodia’s Svay Rieng University. He helped lead the research. Bunyeth told the AP, “I was really surprised and excited to see the real fish for the first time.”

Researchers say the sightings give them new hope for the future of the species. Another name used for the species is “ghost fish.”

“This rediscovery is very exciting, positive news,” said Zeb Hogan. He is a fish biologist at the University of Nevada, Reno, who was part of the research team.

This undated photo provided by Chhut Chheana shows a researcher working on a giant salmon carp Aaptosyax grypus rediscovered in Cambodia. (Chhut Chheana/Wonders of the Mekong via AP)
This undated photo provided by Chhut Chheana shows a researcher working on a giant salmon carp Aaptosyax grypus rediscovered in Cambodia. (Chhut Chheana/Wonders of the Mekong via AP)

But the problems the fish experienced also demonstrate the dangers facing all migratory species in the Mekong. The huge river faces industrial pollution and overfishing, among other problems.

Brian Eyler is director of the Southeast Asia Program at the Stimson Center in Washington, D.C. He was was not involved in the research. Eyler said one issue is that more than 700 dams are built along the river and neighboring waterways. In addition, there are very few workable “fish passages” that help species avoid obstructions.

The Greater Mekong area includes Vietnam, Cambodia, Laos, Thailand and Myanmar.

The researchers said they hope that cooperation with local communities in Thailand and Laos will permit them to confirm whether the fish also still swims in other parts of the Mekong.

I’m Bryan Lynn.

The Associated Press reported this story. Bryan Lynn adapted the report for VOA Learning English.

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Words in This Story

predatory – adj. a predatory animal kills and eats other animals

symbol – n. a sign or objected used to represent something

species – n. a group of animals or plants that are similar and can produce young animals or plants

positive – adj. something good

obstruction – n. something that blocks something or someone from being able to do something