Farmed Atlantic salmon face significant welfare challenges from sea lice infestation, high stocking densities, and delousing treatments that cause substantial harm.
Salmon welfare in aquaculture has traditionally received less attention than terrestrial farm animal welfare, partly due to persistent uncertainty about fish sentience and partly due to the economic importance of the industry. However, the evidence for salmon pain and stress responses is now substantial. Sea lice cause ongoing tissue damage and distress; crowded cages prevent normal behavioral expression; delousing treatments cause acute harm to prevent chronic harm. The welfare costs of current salmon aquaculture are real and significant, affecting billions of individual fish annually.