Here's a theory:

From what I understand about the Toutle and its recovery after the eruption is that the biologists decided to leave the system alone and observe its natural recovery. With that in mind, maybe what they are doing is allowing for a good number of returning fish the opportunity to naturally spawn. Maybe it doesn't happen this year, or even in this decade. If we interfere any more than we already have, we skew the results of the study. I have heard that the Toutle at one time had an incredible run. It would be interesting to see if it ever recovers on its own.

This is the part of science that sucks-research. Especially when you are studying an entire ecosystem. This is a once in a lifetime opportunity to study this system from square one, and it will be an on-going study for years to come. There have been some big suprises already.

Again, these are just my thoughts on this issue. I'm not an expert in any of this, just an interested spectator.

So release that old boot. You'll be doing it for science.