Three Rivers is a tributary of the Nestucca River on the northern Oregon Coast.It’s a special place, especially for anglers, because it carries a lot of fish.One particular fishing hole, 3 miles south of Hebo, sits just below the Cedar Creek Fish Hatchery. It’s where all the hatchery salmon return, fat, shiny and ready to spawn. “See his tail moving?” One angler whispers to another, pointing to a shadow underwater. “There are two fish just sitti…