Recirculating aquaculture systems (RAS) for salmon farming offer improved welfare potential compared to open sea cages, but present their own distinct challenges including water quality management, stocking density, and sensory environment.
RAS offers genuine welfare advantages over traditional sea cage salmon farming. The elimination of sea lice, greater control over water quality, and potential for lower stocking densities can substantially improve fish lives. However, these systems are not inherently welfare-positive — poor management can create suffering at scale very quickly. Salmon evolved as active, migratory fish with complex sensory needs. Depriving them of natural light variation, current to swim against, and environmental complexity may cause chronic stress even in otherwise well-managed systems. The welfare potential of RAS will only be realised if operators actively monitor fish behavior and health rather than treating welfare as an automatic byproduct of the technology.