The difference in operation being that with salmon, once founded the hatchery used what came back there. Except for massive shortfalls. This allowed for some local adaptation. Further, salmon were generally incubated and reared on surface water sources which reflected the "natural" stream temperatures.

WDG steelhead eggs were all collected at Mother sites and eggs distributed around the state. WDG water sources tended to be groundwater/spring which allowed for all the transfers due to disease considerations but also had incubation and rearing occurring on water warmer than local surface waters. So, not only was there no use of locally returning fish (for a long time) but the early life was in water radically different from natural which helped make them poor reproducers in the wild.