WN1A -
Question # 2 - Why are the resident fish doing well and the steelhead are not?

I think a major factor in the success of the resident form is the fact that the anadromous form is not. With the current marine survival conditions for steelhead I believe that there is lot of freshwater habitat that is no longer capable of sustaining the anadromous life history and the resident form is taking advantage of the available habitat.

May be this example will help explain my thinking. For steelhead a potential measure of the productivity of the freshwater habitat would be the number of the smolts/spawning female that habitat can produce. In good times it an average smolts/female value of 35 might fairly representative. Let's assume that we have a river basin with two equal forks; one with excellent habitat and the other with degraded habitat. Further let's assume that the basin productivity is 35smolts/female. However the value in the good habitat fork is 45 smolts/female and in the degraded fork it is only 25 smolts/female.

During good times fish spawning in both forks will be successful and likely to produce more than enough adults to replace themselves. However look what would happen with smolt to adult survival drops to say 5% (at least a few managers feel that currently PS survivals may be that low or lower). In the good fork at 5% survival those 45 smolts would still produce more than 2 adutls however in the degraded fork at 5% survival those 25 smolts would produce only 1.25 adults. In short that fork has become a population sink and if those conditions last for any length of time steelhead would virtually disappear from that degraded habitat. That would leave empty freshwater habitat for the resident form and even in the habitat with little competition from the anadromous juveniles they would be able to increase in abundance to fill that habitat.

BTW -
It is by that same mechanism that when marine survival drops for an anadromous fish both the productivity and carrying capacity of the basin drops. The lower the marine survival rates the lower the carrying capacity becomes. It is for that reason that in tough times like we are currently in it is so damn tough to increase the number of spawners. There just isn't the habitat to support more fish. Further even if all fishing were to end for a number of years there would not be the expected increase in run sizes unless that survival increases.

Tight lines
Curt