What does a recirculating aquaculture system (RAS) do?

A recirculating aquaculture system (RAS) is designed primarily to reuse and filter water within the system, allowing for a more sustainable approach to aquaculture. It continuously circulates water through various filtration processes, which include mechanical and biological filtration, to maintain a suitable aquatic environment for fish or other organisms being cultivated. This closed-loop system minimizes water usage by treating and reintroducing water back into the environment of the aquatic organisms, which significantly reduces the overall water consumption and helps to conserve this precious resource.

The emphasis on reusing and filtering water is critical because it enables aquaculture operations to be more environmentally friendly and reduces the reliance on external water sources. By maintaining water quality through constant recirculation and treatment, a RAS can support higher densities of aquatic species while mitigating the waste produced.

The other choices do not accurately represent the primary function of a RAS. For instance, while it does contribute to efficient feeding practices, it does not inherently reduce the need for supplemental feeding. Additionally, RASs are not designed to dispose of waste directly into the ocean, nor are they limited to cultivating only freshwater species, as some systems can also support marine organisms.