One of the other things associated with salmon feeding steelhead is that as more salmon spawn and die, the steelhead smolt at younger ages. And, when the smolts are younger the carrying capacity for smolts raises. So, you put more salmon into the stream and you get more steelhead smolts out. At the same time, reducing salmon spawners increases age and reduces number of smolts.

So, steelhead carrying capacity to produce smolts varies with the amount of stream spawned and reared in and the amount of salmon that spawn. Conveniently, then, as reduce salmon escapements and/or habitat access (lose tributary spawning and such) the escapement goal declines which is just what recent analysis keeps showing.

And this is independent of what goes on in the ocean.