Positive Welfare Indicators for Farmed Atlantic Salmon

Moving beyond mortality and disease metrics, researchers are identifying positive welfare indicators for farmed Atlantic salmon — behaviours and states associated with good fish experiences, not just absence of suffering.

Key Facts

Atlantic salmon farming produces approximately 2.8 million tonnes annually, predominantly in Norway, Chile, and Scotland.
Traditional welfare metrics focus on mortality, disease prevalence, fin damage, and parasite burden.
Positive indicators under development include voluntary swimming patterns, feeding motivation, and shoaling cohesion.
Research shows salmon in enriched conditions — with current variability and refuges — show increased exploratory behaviour.
Operant conditioning studies demonstrate salmon can learn and remember, suggesting capacity for positive learning experiences.
The Salmon Welfare Index developed in Norway combines multiple welfare domains into a composite farm-level assessment.

Welfare Considerations

Positive welfare science for farmed salmon is advancing rapidly, driven by recognition that mortality-based metrics miss the quality of experience during a fish's life. Voluntary swimming patterns — fish actively choosing to use varied areas of a pen, rather than being pushed to the periphery — are emerging as reliable positive indicators. Feeding motivation assessed by response latency and active competition for feed indicates fish in a state compatible with positive experience, while depressed feeding suggests illness, stress, or poor water quality. Shoaling cohesion — whether fish swim in coordinated groups or show erratic individual movement — reflects social welfare state. Current variability enrichment, which allows salmon to choose between faster and slower water flow, appears to activate natural rheotactic behaviour and is associated with reduced cortisol. The challenge for the industry is translating these scientifically interesting indicators into practical, cost-effective daily monitoring protocols that influence management decisions in real time.

What You Can Do

Support research institutions working on practical positive welfare indicator tools for commercial salmon farms.
Ask salmon producers and retailers about the welfare assessment protocols they require from suppliers.
Advocate for regulatory inclusion of positive welfare metrics alongside existing disease and mortality requirements.
Choose certified salmon products where welfare reporting goes beyond mortality rates.
Reduce salmon consumption while welfare science catches up to the scale of production challenges.