Steelhead evolved to require repeat spawners. I have seen data from AK and Kamchatka where the run is 50-90% repeats. I had thought, way back, that steelhead were just big trout and letting the whole population spawn once (works well for trout) would work for them. It doesn't. Somehow, we need to find ways to significantly increase the number of repeats along with all the other recovery actions.