Global Assessment of Migratory Freshwater Fishes

The assessment identifies 349 migratory, transboundary freshwater fish species that potentially meet CMS Appendix criteria, with 325 not yet listed. These species are facing rapid declines due to connectivity loss, habitat degradation, and overexploitation. The report emphasizes the need for basin-scale cooperation in priority areas such as the Amazon, Mekong, and Danube, proposing a 'toolbox' of CMS instruments—including Appendix listings, Action Plans, and MOUs—to restore 'swimways' and ensure the survival of these ecologically and economically vital species.

• The global assessment identified 349 migratory, transboundary freshwater fish species that potentially meet CMS Appendix criteria; 24 are already listed, leaving 325 candidates for prospective action.
• Migratory freshwater fish populations have decreased by 81% over the last 50 years, with 'megafish' (the largest migrating species) experiencing a more severe crash of 94%.
• The primary drivers of decline for these species include connectivity loss from barriers like dams and weirs, altered river flows, habitat degradation, overexploitation, bycatch, and pollution.
• Asia has the highest number of threatened transboundary migratory freshwater fish (205 species), followed by South America (55), Europe (50), Africa (42), North America (32), and Oceania (6).
• A specific case study of the Amazon basin identified 21 migratory, transboundary species that meet the criteria for Appendix II listing, noting that over 90% of fisheries landings in the Amazon are estimated to come from migratory species.
• The report identifies several high-value river basins for urgent coordinated cooperation, specifically the Amazon, La Plata–Paraná–Paraguay, Danube, Mekong, and Ganges–Brahmaputra–Meghna.
• The assessment proposes two implementation pathways: 'High-readiness' for species occurring in two or more CMS Parties where action can proceed immediately, and 'High-need, membership-limited' contexts (such as the Mekong Region) where engagement with non-Party Range States is required.

APA

Hogan, Z., Bess, Z., Thieme, M., & Stoffers, T. (2026). Global Assessment of Migratory Freshwater Fishes. WWF International. https://www.worldwildlife.org/documents/2281/FINAL_26_3202_UN_CMS_Migratory_Fish_Report_v6c_031826_uL4zPT8.pdf

Chicago

Hogan, Zeb, Zach Bess, Michele Thieme, and Twan Stoffers. Global Assessment of Migratory Freshwater Fishes. WWF International, 2026. https://www.worldwildlife.org/documents/2281/FINAL_26_3202_UN_CMS_Migratory_Fish_Report_v6c_031826_uL4zPT8.pdf.

Wikipedia

{{cite report |last1=Hogan |first1=Zeb |last2=Bess |first2=Zach |last3=Thieme |first3=Michele |last4=Stoffers |first4=Twan |title=Global Assessment of Migratory Freshwater Fishes |publisher=WWF International |date=2026 |url=https://www.worldwildlife.org/documents/2281/FINAL_26_3202_UN_CMS_Migratory_Fish_Report_v6c_031826_uL4zPT8.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{hogan2026global, author = {Hogan, Zeb and Bess, Zach and Thieme, Michele and Stoffers, Twan}, title = {{Global Assessment of Migratory Freshwater Fishes}}, institution = {WWF International}, year = {2026}, url = {https://www.worldwildlife.org/documents/2281/FINAL_26_3202_UN_CMS_Migratory_Fish_Report_v6c_031826_uL4zPT8.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }