Fish are a vital source of protein and other nutrients for humans, as well as an important part of the ocean's ecology. But overfishing has become a crisis. It is estimated that 90 percent of the world’s fisheries are being fished either at or over their capacity, while some species have been driven to extinction. Can an innovative farming method, which grows fish on dry land, solve the problem? Abby Bertics, The Economist’s science correspondent, investigates. Tackling overfishing is a problem that needs to be solved in the ocean but also by using aquaculture, according to George Clark of the Marine Stewardship Council. At a small shrimp farm in California, Steve Sutton, the boss of TransparentSea, explains how recirculating aquaculture systems (RAS) work. John Sällebrant, Salten Smolt’s production manager shows how RAS can be scaled-up at a Norwegian salmon farm. Plus, Matt Craze, a consultant at Spheric Research, and David Cahill of Pure Salmon, explore the future of fish farming. Alok Jha, The Economist’s science and technology editor, hosts.  For full access to The Economist’s print, digital and audio editions subscribe at economist.com/podcastoffer and sign up for our weekly science newsletter at economist.com/simplyscience. Hosted on Acast. See acast.com/privacy for more information.