Hatchery supplementation of wild salmon populations raises welfare questions about captive rearing conditions and release stress.
Hatchery salmon welfare is often treated as secondary to production numbers, but the quality of welfare during rearing directly affects both fish wellbeing and post-release survival. Chronic stress from overcrowding impairs immunity, behaviour, and physiology in ways that persist post-release. Improving hatchery welfare standards serves both individual fish and population conservation goals.