I am a biologist, and I personally think that the genetic impacts of hatchery outplanting over many generations is under appreciated as a potential explanation for slow recovery of some populations. Fish populations maladapted to their river systems would show many of the same symptoms of a habitat-limited population, and it would take many generations of selective pressure to re-build a population well-suited to any specific system even if habitat was pristine. So if more adults spawning does not result in more smolts produced, perhaps is isn't necessarily the habitat that always is the only culprit to blame. And before I get jumped on here, I'm not saying that habitat isn't also a big player in low freshwater productivity. In fact I think habitat always limits populations. But there are quite a few systems that used to support decent runs, continue to have good habitat conditions, yet don't seem to be recovering as might be expected.