Rainbow trout are one of the most commonly farmed fish globally, with welfare considerations spanning stocking density, water quality and slaughter methods.
Trout welfare research has advanced significantly in recent years, documenting that trout respond to painful stimuli in ways consistent with suffering, show conditioned fear responses and display behavioral indicators of both positive and negative welfare states. High stocking densities cause elevated aggression, increased injury rates (particularly fin damage), feeding competition and chronic stress. Water quality management - particularly dissolved oxygen levels - is critical: hypoxic conditions cause acute distress. Pre-slaughter welfare has received growing attention, with percussive stunning now recognized as more humane than asphyxiation in ice slurry. Trout welfare lags behind salmon in both research investment and regulatory standards - an inequity worth addressing given the scale of trout production globally.