fishwithnoeyes -
While I would be surprised if similar "oscillatiuons" had not happen in the past we have not see the kind of extremely poor marine survival of steelhead that we have seen in the last decade since before the 1950s.

I believe that the survival scale been the resident and anadromous life forms in many of our river systems has further been tipped in favor of the resident forms due to increases in degraded habitats.

Between those two factors in areas such as Puget Sound there has not anytime in many decades where the anadromous life history has been at such a natural selection disadvantage.

Tight lines
Curt