Aquaculture Recirculating Systems: Welfare Benefits and Challenges

Recirculating Aquaculture Systems (RAS) offer significant welfare and environmental advantages over traditional pond and cage systems.

Key Facts

RAS filter and recirculate up to 99% of water, allowing precise control of all water quality parameters
Temperature, oxygen, pH, and ammonia can be managed optimally regardless of external conditions
RAS allows indoor land-based production, reducing disease risk from wild fish contact
Higher capital and energy costs can limit adoption despite welfare and environmental advantages
Stocking density in RAS still requires careful management — the technology does not eliminate density effects
Emerging RAS systems are being developed for salmon, shrimp, sea bass, and other major species

Welfare Considerations

RAS technology represents a significant opportunity to improve aquaculture welfare by providing consistently optimal water quality conditions, eliminating exposure to wild pathogens, and enabling year-round production without seasonal temperature stress. However, RAS is not a welfare guarantee — high stocking densities remain a welfare concern regardless of water quality, and system failures can be catastrophic when backup systems are inadequate. Welfare-positive RAS requires appropriate density management, robust redundancy for life support systems, and continuous monitoring. As the technology matures and costs reduce, RAS could underpin a major shift toward higher-welfare aquaculture across species.

What You Can Do

Look for aquaculture products from land-based RAS systems when available
Ask seafood retailers about the production systems used by their suppliers
Support investment in RAS technology development as a welfare-positive aquaculture approach
Advocate for welfare standards to be applied to RAS systems, not assumed by default
Support policy frameworks that incentivise transition to RAS in appropriate contexts