Atlantic Salmon Rearing Welfare in Land-Based RAS

Recirculating aquaculture systems (RAS) for Atlantic salmon rearing offer welfare advantages over sea cage culture but introduce new challenges requiring careful management.

Key Facts

RAS allows year-round production independent of sea conditions and temperatures
High stocking densities possible in RAS require excellent water quality management
Ammonia, CO2, and dissolved oxygen are the primary water quality parameters in RAS
Salmon in RAS show lower lice burden but face risks from system failure events
Several large RAS salmon facilities have been established in UK, US, and Nordic countries

Welfare Considerations

Salmon welfare in land-based RAS involves different welfare trade-offs compared to sea cage culture. RAS eliminates sea lice exposure and most environmental welfare risks while enabling precise environmental control. However, high stocking densities and chronic recirculated water exposure increase the importance of water quality management. System failures including pump breakdowns or filtration collapse can cause rapid water quality deterioration with mass mortality. Continuous artificial light management affects circadian rhythms and stress responses. Salmon in RAS have fewer opportunities for natural behavior including depth use and schooling behavior comparable to sea conditions. Welfare monitoring in RAS requires instrumentation and alarm systems for key water quality parameters.

What You Can Do

Support welfare certification that includes RAS-specific welfare standards for salmon
Advocate for mandatory backup power and monitoring systems in RAS facilities
Choose salmon from RAS producers with documented welfare monitoring outcomes
Back research into optimal environmental parameters for salmon welfare in land-based systems