Wild salmon have complex social behaviors and responses to conspecifics that affect their welfare during migration, spawning, and in relation to aquaculture impacts on wild populations.
Social welfare in wild salmon is an emerging area of welfare science that complements the more established focus on individual pain and stress. Salmon are not fully solitary — they school for protection, use conspecific cues to navigate, and compete socially for spawning access in ways that affect both individual welfare and reproductive success. The welfare implications of human interventions — fish ladders, hatchery releases, escaped farmed salmon — operate partly through social channels: fish ladders concentrate salmon at high densities causing social stress; hatchery fish with reduced social learning capacity integrate poorly with wild populations; escaped farmed salmon compete with wild conspecifics for spawning sites while producing offspring with lower survival rates. Protecting wild salmon welfare thus requires protecting the social ecology of their populations alongside individual fish welfare.