Sea lice infestations on farmed Atlantic salmon cause chronic pain, open wounds, and behavioral changes that represent one of the most significant welfare challenges in global aquaculture.
Sea lice cause lesions that expose raw tissue, creating persistent pain signals that impair normal behavior and stress fish continuously. Research shows infested salmon have elevated cortisol, reduced growth, and behavioral indicators consistent with chronic pain. The scale of lice infestation across global salmon aquaculture represents one of the largest ongoing animal welfare problems by individual count.