No, I was just suggesting taking a varied genetic sample of a certain "wild" strain.
For example if you sampled a pure wild stock from several fish of that stock, you would find they are almost exactly the same, except for slight differences. These differences are what result in the survivability of the stock. Some of the strain might feed on slightly different things in the ocean, or pick different areas to spawn. Which during poorer feed populations in the ocean, or flood, or drought, would help at least the survivability of some.
I would be willing to bet that if you took a group of hatchery fish, that they would be very similiar, almost like brother, and sister, and lets say the combination of the too alike is not a good thing. Habits are very similiar. If an environmental conditions are unfavorable, it results in destruction in the main population, and as I stated in my previous post due to inbreeding, unfavorable genetic traits are produced.
I was suggesting getting a varied representative sample of the strain. This is what happening when brood stocking is performed like at the Sol Duc Snyder Creek hatchery.
On a "dead" river perhaps get a wide varied sample of wild stock from similar rivers, and hopefully the genetics necessary for that river are contained in that sample where natural process can take over. Though if environmental conditions led to the "dead" river, and they haven't been corrected. Even with the right strain the river will remain barren. Having the right stock isn't always the answer. Having the right nutrients, preventing over fishing, water temperature, good spawning areas, and other factors all play a role.