Recirculating aquaculture systems (RAS) on land offer better environmental control than sea cages, potentially enabling improved welfare through optimised water quality and disease management.
Land-based RAS represents a potential welfare advance in aquaculture by enabling precise control of water quality, temperature, oxygen, and other parameters that determine fish welfare. Disease incidence can be dramatically reduced, eliminating welfare-harming disease events and the stressful treatments they require. However, RAS design must actively support fish welfare: high stocking densities are possible in optimal water quality but can still compromise welfare through social stress. The welfare potential of RAS is conditional on operators using environmental control to optimise fish welfare rather than simply maximise stocking density.