Young salmon migrating to the ocean face gauntlets of hydroelectric dams, predators, and warming waters that kill the majority before they reach the sea.
The migration gauntlet faced by juvenile salmon involves acute suffering at multiple stages. Turbine passage through dams causes physical injury including barotrauma. Thermal stress in warming rivers pushes fish into physiological distress. High predator concentrations at dam tailwaters create extended pursuit and capture stress. Dam removal has shown dramatic improvements in salmon survival and represents the most direct welfare intervention available.