My argument assumes that the Bonneville fish counts are both quantitative and accurate. If they are not, then the argument is like a court case losing it's prime witness.

The data cannot say anything about the pre-1938 (ie, "historical") fish counts and how they were impacted by commercial fishing practices. But it can say a bunch about what happened after 1938, especially as it relates to upstream hatcheries and dams built during the 40's, 50's, and 60's.