Norway is the largest exporter of salmon in the world. And while some of those fish are wild-caught, many are raised in "fish farms"- large cylindrical pens made of nylon in the open water. Sometimes these farmed fish escape, mixing with the local population and causing ecological issues. We see farmed fish in a Norwegian fjord and hear about potential solutions to the problem.Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy