Recirculating aquaculture systems (RAS) for Atlantic salmon offer potential welfare improvements over sea cage farming, but also introduce novel welfare challenges related to water quality, stocking density, and sensory environment.
RAS salmon production removes some sea cage welfare concerns, such as sea lice infestation and environmental variability, but introduces new challenges. High mechanical noise levels from pumps and filtration systems may cause chronic stress. Reduced environmental complexity compared to natural water bodies can impair normal behaviour. Water quality management is critical; ammonia spikes cause acute distress. Research is needed to establish welfare standards specific to RAS environments that address these novel conditions.