I believe that I would ask this fish biologist the mortality rate of these fish even if they are not caught. You will see hundreds of dead steelhead in the rivers during spring. Do they claim that these fish were caught and died because of it? If so why didn't they wash out during a high water. I have some problem believing that.
To my undestanding some steelhead return to the ocean after going through a cycle and return again the next year but it is already a adult and probably not grow any larger.