Migratory fish blocked from spawning grounds by dams and other barriers experience significant welfare harm, and dam removal is among the most effective single interventions for migratory fish welfare.
Migratory fish barrier welfare harm is profound. Fish with strong natal homing — salmon, steelhead, shad — are blocked from reaching spawning grounds that represent the culmination of their biological purpose. The physiological stress of attempted passage, combined with reproductive failure for those that cannot pass, represents significant welfare harm for individual fish and population-level consequences. Dam removal that restores migratory access provides direct, measurable welfare improvement: fish can complete their biological migrations, spawn successfully, and die in their natal streams as natural history intends. The welfare case for dam removal in rivers where the benefits outweigh the losses is strong.