Community models could help conserve the disappearing migratory freshwater fish [Commentary]

When the United Nations Convention on the Conservation of Migratory Species of Wild Animals (CMS) published its Global Assessment of Migratory Freshwater Fishes report earlier this year, the numbers confirmed what riverine communities had suspected for decades. Migratory freshwater fish populations have dropped 81% globally since the 1970s. Nearly all (97%) of the 58 fish species listed under the convention now face extinction. The report, drafted in collaboration with the UN Environment Programme-World Conservation Monitoring Centre (UNEP-WCMC) names the Ganges-Brahmaputra-Meghna (GBM) river system as a global priority region. Zeb Hogan, a fish biologist and one of the report’s lead authors, describes the GBM basin as among South Asia’s greatest migration landscapes. It is a single connected pathway from Himalayan headwaters down to the Bay of Bengal. Yet, despite supporting an immense biomass of migratory species, the basin is collapsing under severe habitat fragmentation driven by aggressive hydropower expansion and altered flow regimes. Public debate about the GBM usually stops at the lower reaches, majorly at barrages like Farakka. The damage is worse far above the plains. In the high-altitude headwaters of the Indian Himalayan Region, the lifelines that flow-dependent species depend on are being cut apart piece by piece. Cascading hazards and the dislocation of aquatic life In late August 2026, a massive ice and rock avalanche struck the Nepal-Tibet border. The debris tore into the Lende Khola before surging down the Bhote Koshi and Trishuli rivers. Monitoring stations run by the International Centre for Integrated Mountain Development (ICIMOD) at…This article was originally published on Mongabay