So far as I know (and I can't lay my hands on my favorite reference right now) there is no run of eulachon (Columbia River smelt) in the Skagit, Though they do occur in some of the major river systems farther north in British Columbia (Skeena, Nass). There are several other varieties of smelt in Puget Sound and along the coast, and most, if not all of them spawn on the saltwater beaches or in brackish water.