One thing about steelhead, at least winters, is that I have had nobody ever able to show a good data set of S/R from smolting to first return to spawn that averaged 1. The caveat was that you had to sample 100% of the run for age because age varies over time at return. This held for Waddell Creek in the 30s and 40s and held on the streams I looked at into the 00s. You need repeat spawners, almost period.

Looking at smolt age versus R/S as smolts got younger R/S increased. It looked like if the mean smolt age was about 1.5 that R/S=1. This may explain why, in general, the hatchery runs worked as they were age-1.

You can get younger wild smolts by significantly increasing salmon escapements but that's a non-starter.

It also means that programs to produce age-2 and older hatchery smolts is a non-starter.