In answer to seabeckraised's question about summers, I would say no planting. Summers have shown a greater ability to go feral than winters. In OR, the laddered a barrier that allowed winters into summer habitat. Summers declined (competition). I would expect the summers to similarly compete with and lower the winter population. Unless, of course, the summers settled in tributary/reach(above a barrier) that was naturally devoid of winters.

As to where there are lots of steelhead one can loo at Kamchatka where they are abundant in the streams they inhabit. Couple pieces of additional information is that the fraction of repeat spawners is well north of 50% and the Russian managers aim for a minimum of 1 kg/sq metre of spawning pinks and chum. That's the baseline. We, on the other hand, like to shoot for about 0.1...