Aquaculture Recirculating Systems: Can Technology Improve Fish Welfare?

Recirculating aquaculture systems (RAS) offer potential welfare improvements over open net pens through water quality control, disease management, and reduced environmental exposure, but introduce new welfare challenges.

Key Facts

RAS circulates water through filtration systems, allowing intensive fish production indoors with controlled conditions
RAS allows production far from natural water bodies, reducing environmental and disease interactions with wild fish
Water quality parameters including oxygen, temperature, and ammonia can be precisely controlled in RAS
Equipment failures in RAS can cause catastrophic mortality events due to high fish density
High capital and energy costs make RAS salmon more expensive than net pen production

Welfare Considerations

RAS offers genuine welfare advantages: elimination of sea lice, precise water quality management, reduced disease exposure, and no dependency on seasonal temperature variation. However, high stocking densities in some RAS facilities, the sensory monotony of indoor environments, and the catastrophic welfare events caused by equipment failure represent significant welfare concerns. The reliability of life support systems is a critical welfare issue - a power failure or filter malfunction in a high-density RAS can kill hundreds of thousands of fish rapidly. Welfare assessment of RAS must consider both normal operation and failure mode consequences.

What You Can Do

Ask retailers about production method for farmed salmon - RAS origin may be welfare-relevant
Support development of welfare standards specific to RAS production including stocking density and enrichment
Advocate for mandatory backup systems and failure protocols in RAS operations
Support research into optimal RAS conditions for fish welfare alongside production efficiency
Engage with aquaculture innovation bodies developing next-generation welfare-positive production systems