I see the part on accumulative effects. One thing to consider, which is mentioned at the start of the article, is local adaptation to specific streams. Some fish adapted to live in conditions well above what "normal" rainbows existed at. Consider the artifical selection pressure heavy angling and no temperature closure has on the population.
These fish get hammered. Only the strong survive. Given that it's still a world class fishery despite
Mans best efforts to **** it up, it makes me wonder.
Mind you, that depends on a large gene pool. Small, isolated cutty streams don't have that luxury, and my impression is that they'd be more susceptible.