Recirculating aquaculture systems (RAS) offer promise for sustainable fish farming but present specific welfare challenges that require careful management to address.
Recirculating aquaculture systems represent a double-edged development for fish welfare. On one hand, they eliminate many open-net cage problems: sea lice infestations, exposure to wild pathogens, water quality dependence on external conditions, and escape of farmed fish into wild populations. On the other hand, RAS environments present distinct challenges. Fish in closed systems cannot escape poor local conditions; pump noise and artificial lighting cycles may disrupt normal behavior; and high densities combined with intensified production pressure create chronic stress. The welfare potential of RAS depends heavily on management quality, stocking density policies, and commitment to fish welfare monitoring as part of system design and operation.