Willi wrote:

I disagree. IMO, by carefully managing hatcheries the result can be more
natural, but hatchery produced fish will always be different than
naturally spawned wild fish. Hatcheries are a last resort for restoring
native, wild fish populations.

I agree with you, Willi, but with the caveat that I think hatcheries
could be much more effective than they are now, but it would cost money.
I suspect that a big problem (maybe THE problem) is that the fish that
are raised and survive in hatcheries are those best adapted to hatchery
conditions, which are very benign compared to wild conditions. They
don't have to deal with predators, weather and water conditions, and
diseases in the same way that wild fish do. In the end, you get a cohort
of fish that hasn't been culled by natural conditions, so there is a
"drift" of their genetics toward adaptation to man-made hatchery conditions.

In principle, these problems could be addressed by more natural
conditions in the hatchery, but the cost would be very high.