Salmon can grow very large: up to 1.5 meters long. They eat herring, smelt and crustaceans. The first years of life is spent in fresh water, after which they migrate to sea. After 1 to 3 years at sea, they migrate back to their place of birth to spawn. There is little known about where they stay at sea. From marked specimen, it appears that a large number of salmon migrate to waters around Greenland, thousands of kilometers from their spawning grounds.