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KEY POINTS:
Migratory freshwater fish populations have declined 81 percent globally since 1970.
97 percent of listed migratory fish species are threatened with extinction, with hundreds more newly identified as at risk.
Weak international cooperation — despite hundreds of rivers and lakes crossing borders worldwide — is a barrier to protecting species and restoring ecosystems.
Migratory freshwater fish populations have declined by 81 percent worldwide since 1970, a collapse that underscores the urgent need for coordinated river and lake management across national borders, the United Nations warns.
A report published today — the first global review of migratory freshwater fish in 15 years — greatly expands the number of assessed species, from 3,000 to roughly 15,000. Researchers identified 325 freshwater fish species with significant ecological, economic, and cultural value as in need of protection.
They join the 97 percent of migratory fish species already listed under the Convention on the Conservation of Migratory Species of Wild Animals (CMS) that are currently threatened with extinction.
“By aligning science, policy, and international cooperation, governments can safeguard the world’s remaining great freshwater fish migrations and the communities and ecosystems that depend on them,” Amy Fraenkel, the CMS executive secretary, says in a statement.
The report coincides with the COP15 convention on global migratory species, hosted this week in Brazil. A focal point of the gathering is a proposed five-year action plan to recover the populations of two of the Amazon basin’s largest migratory catfish species, the laulau and gilded catfish. Both are among 20 species in the Amazon with “unfavorable conservation status” and contribute to the region’s $436 million annual migratory fish economy. The two catfish species, each capable of growing to hundreds of pounds, are key sources of protein for millions of people.
If approved, the landmark action plan would implement protected migratory corridors, fishing regulations, and joint monitoring programs across rivers in Brazil, Bolivia, Colombia, Ecuador, Peru, and Venezuela.
“These fish don’t recognize borders, they migrate thousands of kilometers across many nations in this region, and that’s exactly why this type of action plan is so important,” Michele Thieme, deputy lead of freshwater for the World Wildlife Fund, tells Circle of Blue. “I think this is precedent-setting, and I’m hopeful that we can look back and say that this was a moment that helped to change the trajectory for some of these fish.”
Improving fish health is intrinsically linked with improving habitat and water quality, researchers say. The freshwater migratory fish crisis is simultaneously a watershed health crisis.
“Migratory fish are both indicators and engineers of river health,” Thieme says. “So when we see their populations collapse, it’s a signal that there are broader issues with the ecosystem.”
Collaborative approaches to managing freshwater systems remain rare across the world, despite transboundary lakes and rivers accounting for 60 percent of the world’s freshwater flows and 47 percent of the planet’s land surface falling within shared basins.
Just one-fifth of the 153 countries that share waterways have significant cross-border resource management agreements with their neighbors in place. Many countries have recently acted to the contrary, securing their own water supplies at the expense of other nations.
In September, Ethiopia officially inaugurated its $5 billion Grand Renaissance Dam, giving them control over Nile River flows into Egypt. Water releases from dams in the Indian Himalayas caused flooding in downstream Pakistan during last summer’s monsoon season. At least 40 new rare-earth mines opened last year near waterways in Myanmar that have been shown to leak pollution into the Mekong and Irrawaddy rivers. And Brazil continues its Arco Norte project, an effort to increase ship traffic throughout at least three confirmed rivers in the Amazon rainforest.
“The key is being at the table early in the process of projects to help influence key decisions,” Thieme says. “Once you get to the environmental impact assessment stage, it’s often too late.”
All of these basins are among seven identified in the report as “priority regions,” where the greatest number of at-risk species could benefit from intervention. A majority of at-risk species in the report — 205 species — are endemic to Asian waters.
Financial arguments for prioritizing fish health often resonate with governments. The global freshwater fish market is expected to reach $211 billion in 2026, and grow to upwards of $241 billion in 2031, according to Mordor Intelligence.
But economic growth need not only come at the expense of habitat, as recent landmark collaborations have shown.
Earlier this month, Seattle City Light, a public utility, and three tribes in Washington state announced an agreement to renew the operational licenses for three hydropower dams on the Skagit River on the condition that salmon recovery, flood prevention, resource restoration, and riparian conservation are prioritized alongside renewable energy.
Transboundary freshwater fishery cooperation is important for both beloved species — such as golden mahseer, the “Himalayan Tiger of the River,” which enjoys royal protection in Bhutan, swims in protected pools in Indian temples, and is honored as the national fish of Pakistan — and those still to be included in the scientific record.
Despite their global decline, 309 species of freshwater fish were newly named in 2025 — the third-most in a single year since 1758.
“Unlike animals that migrate across land, species that migrate through fresh waters have only one option,” Thieme says. “Let’s not forget the importance of rivers in delivering so many different values to society, and make sure that these corridors are baked into our plans for how we use water, energy, and all other kinds of development.”