‘Critical’ Mekong fishes threatened with extinction

Posted on March, 04 2024

Mekong fishes vital for tens of millions of people and health of river but one-fifth face extinction
  • At least 1,148 fish species in the Mekong – around 25% – are found nowhere else on Earth
  • World’s largest inland fishery sustains at least 40 million people and valued at US$11 billion
  • 19% of assessed fishes threatened with extinction, including mega and migratory species
The Mekong River’s dazzlingly diverse fishes are critical for the health, food security and livelihoods of tens of millions of people across the region as well as the overall health of the river system, but they are under ever increasing pressure with one in five already threatened with extinction, according to a report published today by 25 regional and global organizations.
Mekong’s Forgotten Fishes details the extraordinary variety of fish species in the river – with at least 1,148 making the Mekong the third most biodiverse river after the Amazon and Congo. The first-of-its-kind report celebrates this wealth of species – from the world’s most massive freshwater fish to one of its most minute, from fishes that ‘talk’ and ‘walk’ to fishes that spit water to knock unsuspecting prey into the river. The Mekong is also home to one of the largest migrations on Earth in terms of numbers of animals, with an estimated 5 billion fishes on the move.

The report highlights the critical role of all these fishes in maintaining the health of the Mekong River Basin and supporting societies and economies across the region. The Mekong boasts the world’s largest inland fishery, which accounts for over 15 per cent of the entire global inland catch, generates over US$11 billion annually, and is central to the food security and livelihoods of over 40 million people in communities across the basin.
But the Mekong’s fishes continue to be undervalued and overlooked by decision makers and at least 19 per cent of assessed species are now estimated to be heading towards extinction, with 18 species already listed as Critically Endangered by the IUCN Red List of Threatened Species.* However, a staggering 38 per cent of species are considered Data Deficient, meaning too little is known about them to gauge their conservation status – and that the number of threatened species is likely far higher.

“The alarming decline in fish populations in the Mekong is an urgent wake-up call for action to save these extraordinary – and extraordinarily important – species, which underpin not only the region’s societies and economies but also the health of the Mekong’s freshwater ecosystems,” said Lan Mercado, WWF Asia-Pacific Regional Director. “These fishes have swum through our civilizations and cultures for millenia and millions of people still depend on them every day. But overlooked by decision makers, they are disappearing. We must act now to reverse this disastrous trend because the communities and countries of the Mekong cannot afford to lose them.” 

The report highlights the unprecedented combination of threats that are driving the decline in the Mekong’s fishes, including habitat loss, hydropower dams fragmenting free flowing rivers, conversion of wetlands for agriculture and aquaculture, unsustainable sand mining, invasive species – and the worsening impacts of climate change. Together, these threats are devastating fishes and fisheries with fish populations in Tonle Sap collapsing by 88 per cent between 2003-2019 and an estimated one-third fall in the economic value of the Mekong fishery between 2015-2020.

Losing these fisheries would have huge impacts on millions of people and trying to replace them would be extremely costly in terms of increased deforestation to free up more land for crops and livestock, water use and greenhouse gas emissions. For example, replacing a 50 per cent fall in the Mekong wild capture fishery would require beef production alone to more than double, requiring the conversion of an extra 83,000 km2 of land, an eight per cent increase in regional water demand, and 45 million extra tonnes of Greenhouse Gas Emissions.

But 2024 offers real hope that the region can turn the tide and start to reverse decades of decline in Mekong fish populations. Countries in the Mekong should join the Freshwater Challenge – the largest freshwater restoration and protection initiative in history, which builds on the 30x30 targets for inland waters in the Kunming-Montreal Global Biodiversity Framework.

“The good news is that it’s not too late to restore the Mekong and bring its fishes back from the brink,” said Zeb Hogan, Lead for Wonders of the Mekong, which funded the report. “By factoring the future of fishes and fisheries into decisions that impact the basin while building on the expertise, knowledge and solutions of local communities, we can chart a new course for the Mekong – securing food and jobs for millions, safeguarding cultural icons, boosting biodiversity and enhancing resilience to climate change.”

Along with protecting and restoring freshwater ecosystems, Mekong countries will also need to implement a transboundary Emergency Recovery Plan for Freshwater Biodiversity. This comprehensive 6-pillar plan, which includes letting rivers flow more naturally, improving water quality, and ending unsustainable exploitation of resources, can deliver solutions at the scale necessary to reverse the collapse in Mekong fish populations.

Critically, local communities have already led the way, developing a range of successful solutions, such as community-led Fish Conservation Zones in Lao PDR, which have proven to increase fish populations and diversity – and benefit local fishers. 
“Local fishers and communities have shown that there is hope. Together, we can scale up their solutions. We can protect and restore the Mekong, and use it sustainably for the benefit of societies and economies now and in the future – a future in which the river’s extraordinary freshwater fishes survive and thrive,” said Kathy Hughes, WWF Asia-Pacific Freshwater Biodiversity Lead and the author of the report. “Reversing decades of decline will be hard but it’s possible – if we act collectively and urgently.


Note to editors:

The report was published by  Association Anoulak, Cambodian Fisheries Administration, Conservation International, FISHBIO, IMWI, Inland Fisheries Alliance, InFish, IUCN, IUCN SSC Asian Species Action Partnership (ASAP), IUCN SSC Freshwater Fish Specialist Group, Living Rivers Siam Association, Mandai Nature, Mekong Community Institute, Re:Wild, Royal University of Agriculture, Cambodia, Shoal, Synchronicity Earth, The Nature Conservancy, University of Nevada Global Water Center, USAID, World Fish Migration Foundation, Wonders of the Mekong, WorldFish, WWF and WWT 

For more information: news@wwfint.org

Additional facts and figures:
* Threatened Mekong fishes include a remarkably diverse range of species, including two of the world's largest catfish (weighing up to 300kg), the world's largest carp, the giant freshwater stingray, a striped tiger fish, the mouth-brooding arowana, wolf barb and salmon carp.

Additional quotes from partner organizations:

Harmony Patricio, freshwater fish conservation program manager, Re:wild: “We normally think of under-explored and under-studied places as being places where it is incredibly hard for humans, or any species to survive, but the Mekong River is one of the most biodiverse rivers on the planet and millions of people depend on it. It is a river filled with wonders, from the largest freshwater fish in the world to some fish species, like pufferfish, that are more typically found in oceans. This report is a wake-up call about how fragile the Mekong River is, but the good news is that there are steps that can protect and restore its biodiversity”

Herman Wanningen, Managing Director, World Fish Migration Foundation: "It’s clear that we are risking a new biodiversity crisis for the Mekong River basin. But it’s not too late. This new report gives valuable insights to halt and furthermore improve the ecological status, so the Mekong River will stay full of fish."
Giant freshwater stingray
© Fishbio