Farmed Salmon Welfare in Recirculating Aquaculture Systems

Recirculating aquaculture systems offer significant welfare advantages over open-net salmon farming by eliminating sea lice and disease pressures, though high density and water quality management remain critical welfare challenges.

Key Facts

Recirculating aquaculture systems filter and recirculate water, eliminating pathogen exchange with wild fish
Sea lice cannot complete their life cycle in closed RAS environments, eliminating the primary welfare threat of open nets
Water quality parameters including oxygen, CO2, ammonia, and pH can be precisely controlled in RAS
High capital costs mean RAS salmon are produced at higher prices but with lower environmental impact
Stocking densities in RAS must be carefully managed to prevent chronic stress and fin damage
Light manipulation in RAS can control smoltification timing, improving welfare during life-stage transitions
Several large RAS salmon operations are now commercially viable and scaling globally

Welfare Considerations

RAS salmon farming represents the most welfare-positive currently commercial salmon production system available. By eliminating sea lice infestations and allowing precise control of the aquatic environment, RAS addresses the two most significant chronic welfare problems in conventional open-net farming. However, RAS welfare is not automatic — poorly managed RAS farms with inadequate water quality, overcrowding, or equipment failures can cause rapid welfare deterioration. The welfare advantage of RAS requires operational excellence to realize. Supporting the development and scaling of well-managed RAS operations is one of the most impactful aquaculture welfare interventions currently available to consumers and policymakers.

What You Can Do

Choose RAS-produced salmon where available and labeled to support welfare-positive production methods
Advocate for RAS transition as a welfare improvement requirement in seafood certification standards
Support government investment in RAS technology development and farmer transition support
Encourage supermarkets to set transition timelines from open-net to closed containment salmon sourcing
Support research on RAS welfare optimization including density, lighting, and water quality standards