Applying to the hatchery genetics scenario.
I have the assumption that not all fish in the vedder are actually hatchery fish, and that there are definitely some wild genes left over. I hit some fish that take me for a run every year, and they fight noticeably different to me than the hatchery fish do.
By my logic the "hatchery fish" are wild fish that are just helped along a little - only once removed from the gene pool of wild fish. If that same hatchery fish would be spawned over and over each season then we would have a problem (possible inbreeding complications, etc). In the case of wild broodstock, if that hatchery fish goes and spawns in the wild, it is only 1 generation out of the wild gene pool and shouldn't effect the gene pool much, if at all. Those offspring are still wild fish, they need to hatch out of the ground, make it past all the predation from egg to smolt and have to fight for food just like every other wild fish does.
It actually baffles me when people say that all the fish in the river are hatchery fish. What makes a hatchery fish? Is it the fact that they are helped along a little in the first stages of life, or do you actually think there is a genetic contribution attributed with it? I personally believe a hatchery fish is one helped along, a wild fish is one that had to survive on it's own in the river. If that one that had to survive on it's own had a hatchery parent, I don't see that making it a "hatchery fish".
I'd love for someone to prove that this actually makes the gene pool weaker in the terms of wild brood stock. In the case of using hatchery fish year after year, then yes it could definitely have a huge effect on the gene pool. In my mind, if a fish makes it through everything and comes back to spawn on it's own, it's just as good as any wild fish whether it had a hatchery parent or not.