Recirculating aquaculture systems (RAS) are land-based aquaculture facilities – either open air or indoors – that minimise water consumption by filtering, adjusting, and reusing the water.
Compared to traditional pond or open water aquaculture, the water recirculation process in RAS makes it possible to control the culture conditions and collect waste. In addition, land-based aquaculture avoids escapees and limits external transmission of diseases and parasites. RAS gives promise of more sustainable food production with lower consumption of fresh water, and shorter transport distances, as fish can be grown closer to the markets. By controlling the culture conditions, aquaculture production in a RAS facility can be established almost anywhere, regardless of local conditions. By moving the production on land, it can also mitigate the scarcity of available space and competition for access to sea areas.
On the other hand, a RAS facility tends to be energy intensive and expensive. Investment costs are high, and the recirculation technology consumes vast amounts of energy and requires to be controlled and managed by a skilled workforce. Furthermore, the technology remains to prove its viability on large-scale production, especially concerning saline water environments.