Recirculating aquaculture systems are a way to farm aquatic organisms by reusing the water in the production. The technology is based off of mechanical and biological filters to remove any impurities from the water so it can be put back into circulation. In theory this system can be used for any species one would want to farm, such as fish, shrimps, and clams. 

​

Recirculating aquaculture systems are growing rapidly in many areas of the fish farming sector. Systems are being deployed in production units that vary from huge plants generating many tonnes of fish per year for human consumption to smaller systems used for restocking wild populations or saving endangered species. 

​

The image below represents s general set-up for a recirculating aquaculture tank. The tanks are often circular or rectangular, however some farms utilize other types of tanks. These tanks can be located outside, where they are subject to environmental factors, or inside facilities, where bio-security and environmental factors can be highly controlled. Improvements in filtration and water efficiency has made newer farms utilizing RAS technology more environmentally friendly and able to produce thousands of high quality fish per year. Because the animals are in a completely controlled environment, there is often no need for chemicals or antibiotics, no threat of outside pollutants being ingested, and no threat of escapement into wild populations. At a well-run farm, water exchange and filtration capacity are high enough to ensure any waste suspended in the water is quickly removed and monitors ensure water temperature, dissolved oxygen levels, and salinity are maintained at optimum levels. Additionally, redundancy is key to ensure if a system goes off line, there is a back up in place to assure the survival of the animals.