Salmon hatcheries are used to supplement wild populations but raise welfare concerns about rearing conditions and post-release survival, with evidence of both conservation benefit and unintended harm.
Salmon hatchery welfare requires balancing individual rearing welfare against post-release outcomes. Fish reared in barren, crowded hatchery conditions experience chronic stress that impairs immune function and behaviour - but these conditions are partly justified by high production targets. Enriched rearing environments (cover structures, varied flow, lower density) produce fish with better predator avoidance and foraging behaviour, improving both individual welfare and post-release survival - aligning welfare and conservation objectives. The most welfare-positive hatchery programmes invest in rearing conditions that produce competent wild-type fish rather than maximising throughput at the expense of individual and post-release welfare.