Atlantic salmon farming is a major global industry producing over 2.5 million tonnes annually, primarily in Norway, Chile, and Scotland. Sea lice infestation, disease outbreaks, crowding stress, and inhumane slaughter remain central welfare challenges.
Key Facts
Norway is the world's largest Atlantic salmon producer (approximately 1.4 million tonnes/year), followed by Chile, Scotland, Canada, and the Faroe Islands
Sea lice (Lepeophtheirus salmonis and Caligus elongatus) are ectoparasitic copepods that attach to salmon skin and gills, causing lesions, secondary infection, and significant welfare impact — a chronic industry crisis
Salmon welfare during sea lice treatment is a growing concern: treatments including hydrogen peroxide baths, freshwater immersion, and mechanical cleaner fish (wrasse, lumpfish) all carry welfare costs
Crowding stress at high stocking densities causes suppressed immune function, fin damage, aggressive interactions, and impaired growth — all measurable welfare deficits
Slaughter of Atlantic salmon typically involves electrical stunning or percussive stunning at harvest — both are considered humane when properly implemented, but equipment calibration is critical
RSPCA Assured salmon certification (used by major UK supermarkets) specifies maximum stocking densities, water quality parameters, sea lice thresholds, and stunning requirements
The Norwegian government's Traffic Light System, which regulates farm expansion based on sea lice impact on wild salmon, has driven significant industry welfare and environmental attention
Welfare Considerations
Atlantic salmon welfare in net pens is shaped by a complex of interacting stressors: sea lice cause persistent pain and skin damage; disease outbreaks trigger mass mortality events; crowding suppresses normal behaviour and immunity; and handling during treatments adds acute stress. The welfare and production interests of the industry align on many issues — healthier fish grow faster and have lower mortality — creating genuine incentives for welfare improvement that are largely absent in terrestrial livestock farming. However, the scale of production (billions of fish) means that even small per-individual welfare deficits represent enormous aggregate suffering. Consumer certification labels are effective levers: RSPCA Assured and ASC-certified products provide meaningful differentiation, and retailer commitments to these standards drive farm-level improvement.
What You Can Do
Choose Atlantic salmon with RSPCA Assured or ASC certification — these specify welfare standards beyond basic regulatory minimums
Support the Fish Welfare Initiative's salmon programme, which works directly with farms on practical welfare improvement
Advocate for mandatory sea lice threshold enforcement and welfare-inclusive farm licensing in salmon-producing countries
Reduce salmon consumption where possible, or diversify toward plant-based omega-3 sources (algal oil supplements provide DHA/EPA without the welfare or environmental footprint)
Support research into integrated pest management approaches for sea lice that reduce both welfare costs and environmental impacts compared to chemical treatments