Recirculating aquaculture systems promise to address the environmental and welfare problems of net pen salmon farming, but their welfare track record is still being established.
Recirculating aquaculture systems offer genuine welfare advantages over open net pen salmon farming. The elimination of sea lice, control over water temperature and oxygen, and protection from weather and predators could substantially improve salmon welfare. However, the technology is still maturing, and several high-profile catastrophic mortality events at poorly managed facilities demonstrate that RAS welfare is not guaranteed by the system design alone. Stocking density, water quality monitoring, and emergency response protocols are critical. If implemented well, RAS represents one of the most promising pathways to high-welfare, low-environmental-impact salmon production.