Farmed Salmon Welfare in Recirculating Aquaculture Systems

Recirculating aquaculture systems (RAS) offer potential welfare improvements over open net-pen salmon farming. Understanding their benefits and limitations helps consumers and policymakers assess this growing sector.

Key Facts

RAS farms recirculate water through filtration systems, eliminating sea lice, preventing escapes, and allowing land-based production anywhere
RAS salmon farming has grown significantly in the US, Europe, and Asia as an alternative to open-net pen production
Water quality parameters including temperature, oxygen, and ammonia can be precisely controlled in RAS, potentially improving welfare
RAS eliminates the sea lice problem that plagues open-net farming and requires heavy chemical treatment
Energy requirements for RAS are significantly higher than open-net farming due to pumping, filtration, and oxygenation
Stocking density in RAS can still be high; welfare benefits depend on how density and water quality are managed
Mortality from RAS system failures — power outages, equipment malfunction — can be rapid and catastrophic

Welfare Considerations

RAS salmon farming represents a genuine potential welfare improvement over open-net pen production by eliminating sea lice, controlling water quality, and preventing exposure to pathogens. However, welfare outcomes in RAS depend heavily on management: high stocking densities in a controlled environment can still cause social stress and behavioral deprivation. The elimination of sea lice removes one major welfare problem but does not address fundamental questions about whether salmon in any intensively managed system can have adequate behavioral freedom. RAS also introduces system-failure risk — if water systems fail, mortality can be rapid and complete. The welfare case for RAS is that it removes several serious welfare problems; the remaining questions concern whether density and behavioral enrichment standards will be prioritized.

What You Can Do

Choose RAS-raised salmon over open-net pen Atlantic salmon when purchasing, as it eliminates several serious welfare problems
Support ASC certification for RAS operations, which provides welfare and environmental monitoring
Advocate for welfare standards covering stocking density and enrichment to be part of RAS certification frameworks
Reduce farmed salmon consumption overall to reduce demand for intensive fish production of any kind
Support research into behavioral needs of salmon in RAS and appropriate density and enrichment standards
Ask seafood suppliers and retailers about the farming method used for their salmon products
Learn about the welfare differences between aquaculture production systems and share this information with other consumers