The world’s great fish migrations are collapsing - that’s a problem for millions of people

Key Points:

• Migratory freshwater fish, including species like salmon, sturgeon, and giant catfish, undertake massive journeys essential for their survival, but their populations are rapidly declining due to dams, overfishing, habitat loss, and pollution.
• A global assessment identified 325 migratory freshwater fish species as priorities for international conservation, with 97% of those already listed under the Convention on Migratory Species at risk of extinction, especially large species in Asia experiencing over 95% population declines since 1970.
• Iconic species such as the Mekong giant catfish and the Amazon’s gilded catfish face critical threats from blocked migration routes and habitat fragmentation, severely impacting ecosystems, fisheries, and local cultures dependent on these fish.
• The fragmentation of rivers by dams and other barriers disrupts migration corridors that often cross national borders, highlighting the need for international cooperation and coordinated conservation efforts under treaties like the Convention on Migratory Species.
• Successful restoration efforts, such as dam removals in Washington state, demonstrate that reconnecting rivers and protecting habitats can help migratory fish populations recover, emphasizing the importance of managing rivers as connected ecological systems.