Originally Posted By: BigJim
I presume the reason why the offspring of the mixed stock doesn't return in viable numbers is that they are not truely bred for that system, as we see in so many rivers why hatchery fish fail at making it back in decent numbers.


It is actually even a bigger deal than that (although your point about putting the wrong genes in the wrong river is valid). Even if you used the native genes from a particular river, the fish themselves are much worse off simply by the way they are raised. Check some of the more recent Oregon studies. It has been discussed on this board before.