Sea-run brown trout spend at least part of their life-cycle at sea. They then return to freshwater rivers to spawn. It is thought that they do this more than once over their lifespan. Sea-run trout are common in the surf off river mouths in the spring and summer as they hunt smelt. A fresh sea-run brown trout will be bright silver in colour and have bright orange flesh much like a sea-run salmon. There is no evidence that rainbow trout in New Zealand migrate to sea in the same way as brown trout. Sea-run rainbow trout are known as steelhead in North America.