Vital Freshwater Fish Migrations Collapsing Worldwide, Warns UN
Migratory freshwater fish are in steep decline due to pressures along their paths, including dams, altered flows, habitat degradation, pollution and unsustainable fishing. Restoring rivers and habitats cannot wait.
– UN Environment Programme
Some of the longest, most important migrations of species on Earth are happening beneath the surface of the world’s rivers and many are rapidly collapsing, according to a major new assessment by the UN Convention on the Conservation of Migratory Species of Wild Animals (CMS).
More than 300 species of migratory freshwater fish are in dire need of “urgent coordinated cross-border collaboration” amid this crisis, according to the latest CMS annual report.
The report finds that migratory freshwater fish – a group of species that maintain river health, underpin some of the world’s largest inland fisheries, and sustain hundreds of millions of people – are among the most imperiled wildlife on the planet.
“This assessment shows that migratory freshwater fish are in serious trouble, and that protecting them will require countries to work together to keep rivers connected, productive, and full of life,” says Dr Zeb Hogan, lead author of the report, “Global Assessment of Migratory Freshwater Fishes”.
Migratory freshwater fish populations worldwide have declined by roughly 81% since 1970 and nearly all (97%) of the 58 CMS-listed migratory fish species (including fresh and salt-water species) are threatened with extinction.
According to the report, many migratory fish rely on long, uninterrupted river corridors connecting spawning grounds, feeding areas, and floodplain nurseries, often across multiple countries. When dams, altered flows, or habitat degradation interrupt those pathways, populations can decline rapidly.
CMS recommends governments take steps to safeguard migratory fish and their habitats, including protecting migration corridors, devising basin-scale action plans and transboundary monitoring, and international coordination of seasonal fisheries.
Michele Thieme, one of the 3 authors of the report, who is vice president of World Wildlife Fund-US, said that “rivers don’t recognise borders – and neither do the fish that depend on them.”
“The crisis unfolding beneath our waterways is far more severe than most people realise, and we are running out of time,” she added.
“Rivers need to be managed as connected systems, with coordination across borders, and investments in basin-wide solutions now before these migrations are lost forever.”
The CMS report follows a February 2026 publication of a study by researchers in Spain who examined how ocean warming driven by human burning of fossil fuels is causing a “staggering and deeply concerning loss of marine life”.
– info compiled from Wetlands International (24 March 2026); Common Dreams (24 March 2026)
Original articles here:
https://www.commondreams.org/news/fish-migrations-collapsing
https://www.wetlands.org/vital-freshwater-fish-migrations-are-collapsing-warns-un/
UN’s CMS “Global Assessment of Migratory Freshwater Fishes” report here: