Aquaculture Recirculating System Welfare

Recirculating aquaculture systems (RAS) are land-based fish farming facilities that can offer some welfare advantages over open net pens but introduce new challenges including water quality management, light conditions, and high stocking density.

Key Facts

RAS facilities maintain fish in enclosed tanks with water continuously filtered and recirculated
Unlike sea cage systems, RAS facilities can be located anywhere and are isolated from wild fish populations
Water quality parameters including dissolved oxygen, ammonia, CO2, and pH are monitored continuously in well-run systems
Stocking densities in RAS can be very high, increasing aggression, skin injuries, and stress
Lighting in RAS facilities can be manipulated to control growth and reproduction but may disrupt natural patterns
RAS salmon production is growing as sea lice and disease problems increase costs in open net cage systems
Technical failures in RAS (pump failures, filter blockages) can rapidly cause catastrophic water quality events
The welfare advantages of RAS over net cages depend entirely on management quality and stocking density decisions

Welfare Considerations

RAS technology offers genuine potential welfare benefits over traditional net cage aquaculture - protection from sea lice, predictable water quality, and removal from coastal ecosystems. However, these advantages are not inherent to the technology; they depend on how systems are managed. High stocking densities, technical failures, and inappropriate lighting can cause significant suffering. RAS welfare is determined by operational standards rather than system type.

What You Can Do

Look for RAS-farmed fish from certified systems with published welfare and stocking density standards
Support research into optimal RAS design and management for fish welfare
Advocate for welfare standards that apply equally to RAS and net cage aquaculture
Ask fish retailers about the source and production system of the fish they sell