Grandpa-
No, what I'm saying is that if hatchery fish are left alone (no further introductions) in an acceptable habitat that is not occupied or under utilized they have a chance to evolve over time to become successful in that environment. Nothing to do with good science.

The hatchery fish would not have the chance to be successful if there is not a niche for them. That niche could be from fish gaining access to new habitat (removing barriers such as culverts) or in situations where over-fishing has occurred.

The question is why would anyone be interested in using hatchery fish and the number of generations needed for the fish to reach full productivity when the existing wild fish can do the job better is we would just give them the chance.

Tight lines
Smalma