Sea lice are the most significant parasite challenge in Atlantic salmon farming, causing skin damage, stress, and mortality. Welfare-compatible control strategies balance efficacy with minimising treatment harm.
Sea lice cause genuine suffering in farmed salmon. Attachment sites become painful wounds vulnerable to secondary infection; severe infestations expose the cranium in salmon, directly damaging brain tissue. The welfare calculus of treatment is complex — both infestation and intervention cause harm. Chemical bath treatments involve crowding, air exposure, and chemical stress. Mechanical removal procedures cause scale loss, physical trauma, and handling stress. Every treatment option carries a welfare cost, making prevention the most humane strategy. Integrated pest management combining site selection, wrasse and lumpfish welfare improvements, reduced use of chemicals, and early treatment thresholds represents current best practice.