Atlantic salmon in aquaculture face welfare challenges from crowding, sea lice, handling stress, and restricted behavioral expression compared to their wild counterparts.
Atlantic salmon welfare in aquaculture is compromised by the fundamental mismatch between their natural migratory life history and the confined conditions of net pen aquaculture. Salmon evolved to range across thousands of kilometers between freshwater and ocean, responding to complex environmental cues for migration timing and spawning. In net pens, these behavioral motivations find no outlet. High densities cause crowding stress, aggressive interactions, and fin damage. Sea lice cause ongoing discomfort. Handling during routine operations including grading, vaccination, and treatment causes acute stress that can be lethal in susceptible individuals. Progressive aquaculture companies are investing in welfare assessment tools and improved management to reduce these impacts, though the fundamental constraints of net pen aquaculture limit the welfare improvements achievable.