Farmed Salmon Welfare in Recirculating Systems

Recirculating aquaculture systems (RAS) offer potential welfare and environmental improvements over sea cage salmon farming, but also introduce new challenges.

Key Facts

RAS salmon farms use closed tanks with water treatment rather than open sea cages
RAS eliminates sea lice infestations and reduces environmental impact compared to sea cages
Water quality management in RAS is critical — failures cause rapid welfare deterioration
Stocking densities in RAS can be very high, creating chronic social stress
RAS salmon production is growing rapidly as an alternative to traditional cage farming

Welfare Considerations

RAS technology promises significant environmental and some welfare improvements over sea cage salmon farming. Without sea lice and reduced predator pressure, fish can avoid some welfare harms. However, high stocking densities, artificial lighting cycles and unnatural environments still pose welfare challenges. Water quality in RAS systems must be actively managed — ammonia, CO2 and oxygen levels can rapidly reach welfare-compromising thresholds. Welfare standards for RAS salmon farming are still being developed and need to address these specific challenges.

What You Can Do

Look for salmon certified under welfare-conscious schemes that include RAS standards
Support research into optimal stocking densities and enrichment for RAS salmon
Engage with aquaculture welfare organisations developing RAS-specific guidelines
Choose salmon from producers with transparent welfare monitoring data