The threatened fish of the Mekong River are inching closer extinction, according to a new report that cites piling pressures on the waterway. Though the situation is serious, conservationists say it’s not too late to turn the tide for the river’s freshwater species.

The nearly 5,000-kilometer (3,000-mile) Mekong supports millions of people across six countries, from its headwaters in China to its delta in Vietnam. The river, a key vein in mainland Southeast Asia, faces a rising tide of threats, from unsustainable fishing and invasive species, to hydropower dams and sand mining, all compounded by climate change.

Nearly a fifth of the known fish species in the river are threatened to some degree with extinction, according to a recently release report, “The Mekong’s Forgotten Fishes.” The report was compiled by 25 organizations, including conservation NGOs WWF and Conservation International, and the IUCN, the global wildlife conservation authority, which is responsible for the Red List of Threatened Species.

The report used a threat calculation based on the risk assessments in the Red List. The calculation found that 19% of the nearly 400 assessed Mekong River fish species are threatened with extinction. But the report noted that 40% of the species that underwent risk assessments are considered “data deficient” on the Red List, which means not enough is known about them to determine just how threatened they are. In light of this, the report said, “it’s safe to say that the true number of globally threatened fish species in the Mekong is much higher.”

“The fishes of the Mekong are indicative of the state of the basin,” Marc Goichot, , told Mongabay in an interview. He added that beyond “the intrinsic value of a fish, of a unique species, there is also the fact that they are an indication of food resiliency and an indicator of the climate resilient state of the Mekong.”

The risk of losing these species is why this report “zoomed in on the Mekong,” said Goichot, who was a key reviewer of the report.

A chapter in the report, “Mekong fishes in freefall,” underlines the extinction threat to many species with a flurry of studies documenting the decline of the Mekong, from major fish population collapses in Cambodia’s Tonle Sap Lake, to the overall decline in the value of the river’s fishery.

In a study published in February, the Mekong River Commission (MRC), an intergovernmental organization tasked with promoting cooperative development of the waterway, documented a decline in fish harvests of 25-30% from 2015-2020.

“It’s crucial to approach this issue with a balanced perspective,” the MRC Secretariat told Mongabay in an email. “The Mekong River Basin is influenced by various interconnected factors, including environmental changes, infrastructure development, climate change, and socio-economic dynamics.”

It added that “while the findings of the report underscore challenges faced by communities reliant on the river’s resources, it’s essential to avoid characterizing any period as the ‘most dire.’ Instead, it serves as an important reminder of our duty to ensure its conservation and sustainable management for generations to come.”

The solutions focus on letting rivers flow more naturally, improving water quality, protecting and restoring critical habitats and species, ending unsustainable resource management, addressing nonnative species, and protecting free-flowing rivers and removing obsolete river barriers.

“Keeping rivers free flowing is probably the most cost-effective climate adaptation strategy that one has because free flowing rivers are more resilient. They make people more resilient, prevent natural disasters and support more biodiversity,” Goichot said. “It is win-win-win across the wider understanding of sustainability.”

While nearly half of the Mekong River is in China, the report focuses on the Lower Mekong Basin countries. “That is where the overlap between the fisheries and the biodiversity is the clearest through the dependence of the people on the river,” Goichot said.

He said he hopes restoration efforts can tap into global initiatives, like the Kunming-Montreal Global Biodiversity Framework and the Climate Adaption Summit, which promote nature-based solutions to financial institutions. Chapters of the report also noted the importance of exploring other potential revenue streams for conservation, like recreational fishing and ecotourism.

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  Three critically-endangered Irrawaddy dolphins are spotted in the Mekong River by Kratie in northeast Cambodia. The Mekong’s Forgotten Fishes report referred to the dolphins as “one of the Mekong’s top predators” that rely on a functioning ecosystem of Mekong fish for prey. Image by Anton L. Delgado.

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  The carvings of fish on the outer walls of Bayon Temple in Angkor Archeological Park, a UNESCO World Heritage site in Cambodia, are cited in the Mekong’s Forgotten Fishes report as evidence of the cultural importance of the Mekong’s species. Image by Anton L. Delgado.

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  Three people look out at the dried-out Mekong River, which acts as the natural border between Thailand and Laos. Image by Anton L. Delgado.

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  A fisherman clears his net of its catch in Kampong Phluk, a floating village on Cambodia’s Tonle Sap Lake. The Mekong’s Forgotten Fishes report referred to the lake as “critical for fish, people and nature.” Image by Anton L. Delgado.

Urgent and collective action

The supposed death march of the “Mighty Mekong” is consistently a call to action among conservationists for transboundary cooperation and biodiversity management, as they try to sound the alarm for the health of the river.

Zeb Hogan, who has worked in the Mekong Region since 1996, told Mongabay in an email that “yes, the situation is as dire as it has ever been. But it’s also not too late to protect and restore the Mekong. Reversing the decline is possible with urgent and collective action.”

The forgotten fishes report cites several moments of hope for the river last year: from rediscoveries of presumed extinct species and descriptions of new species, to record sightings of critically endangered species and the capture of the world’s largest freshwater fish.

“The bright spots provide hope and indicate that the Mekong River is still capable of supporting its bountiful fisheries and iconic wildlife,” said Hogan, the program lead for the U.S.-funded conservation project Wonders of the Mekong. “The persistence of these species indicates that it is not too late, there is still hope, and that the river has not been irreversibly damaged — at least not yet.”

Whether or not the six points of the emergency recovery plan amount to success will soon be seen.

“The health of the Mekong River is on a downward trajectory but it’s not too late to ‘bend the curve’ for conservation,” Hogan said. “The question becomes how much can the people in the region afford to lose before governments take action to protect the health of the river and the people and animals that depend on it.”

Banner image: In Kampong Phluk, a floating village on Cambodia’s Tonle Sap Lake, a fisherman collects his catch. The Mekong’s Forgotten Fishes report said there is “evidence of an 88% collapse in the population size of fishes” on the lake. Image by Anton L. Delgado.

Fisheries crackdown pushes Cambodians to the brink on Tonle Sap lake

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