Ideally you need to know what's contributing to the problem before you can resolve it, right?

Granted, a shotgun approach, if economical, is sometimes the best way to start out. You might get lucky. In this case there's no economical shotgun.

Dave, in answer to your original question, I don't see how it can't effect the fish. You've already identified the factors (low flows, increased water temperatures, increased flooding, etc.) that we expect to have the most effect, but I'm curious about things like sea levels and the changes in the estuary system too. What is the rate of sea level increase? Is it noticeable over a period of years, decades, or centuries? Can the upriver spawning fish adapt by spawning lower in the rivers quickly enough to survive? Will the managers come to grips with the situation quickly enough and take the necessary steps to insure that we have enough fish (and genetic variety) left to make the transition?