Fishyologist -
Welcome - great handle!
It appears that you bring a valued and interesting prespective to our discussions - looking forward to additional input from you.

It is important in discussing hatchery versus wild to remember that the fish reared in the natural and hathcery envirnoments are exposed to a very different selective pressures. This is especially acute when talking about fish that spend extended periods of time in freshwater.

For a fish like steelhead it typical that 5% or less of the wild eggs to make it to be a smolt while in the hatchery maybe 80% will become smolts the role of selective pressure can be huge. This means that natural selective pressure operates much more severely on the wild stock than hatchery.

These selective pressures don't operate directly on the genetics of the fish but rather on the various phenotypes of the populations. To illustrate take a trait like swimming speed; obviously the following example isn't a real world one but I think it will illustrate on the selection process may work and what the consequences may be. If the wild environment puts a high value on high swimming speed we would see only the 5% that were the fasts surviving to be a smolt while if the hachery didn't vvalue swimming speed (no advantage in a rearing pong) the slow and the quick would survive equally. I think one can see that the resulting offspring would have different swimming speeds. After even a few generations the hatchery fish would be notably slower.

The big thing with hatchery fish spawning in the wild is whether they are as prodcutive as the wild fish. In the above example the hatchery fish would be slower and therefore less successful in the wild. There a plenty of info one the decreased productivity of first generation of hatchery fish when spawning in the wild. Generally the longer the fish are reared in the hatchery (either as a smolt or the number of generations the broodstock has been in a hatchery) the poor they do in the wild.

In the article at the start of this thread the "success" was where hatchery fish were introduced into vacant habitats and after the initial introduction the returning fish were allowed to adapt (natural selection in operation) to the local environment. The mal-adapted traits are quickly selected against and disappear from the population resulting in a successful population. That is a very different situation that an annual hatchery program where less fit hatchery fish are constantly be infused into the population limiting the selection process.

Tight lines
S malma