You just have to learn each piece of water individually. Some rivers have species of fish that others do not. You could call up your local Biologist or check at the local hatchery for info. On most Northern Rivers there are winter steelhead and after January the big natives come home--at least the rivers in Whatcom and Skagit county. In the spring the Chinook will start showing up but many rivers are closed so it is a good time to fish the lakes.