Atlantic salmon farming in marine net pen systems faces multiple simultaneous welfare challenges including sea lice, crowding, aggression, and environmental variability that require integrated welfare management approaches.
Atlantic salmon welfare represents the largest-scale fish welfare challenge in aquaculture due to the combination of enormous numbers of fish, multiple simultaneous stressors, and the difficulty of managing welfare at marine net pen scale. Each of the major welfare challenges — sea lice, crowding, delousing treatments, environmental events — affects millions of individual fish that have limited capacity for welfare monitoring and individual treatment. Systemic welfare improvement requires addressing root causes through sea lice resistant genetics, lower stocking densities, and earlier disease detection rather than reactive management of established problems.