For precision, from section 3 of the Endangered Species Act, Definitions;

(19) The term “take” means to harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect, or to attempt to engage in any such conduct.

Collecting wild threatened steelhead for broodstock for instance would be take according to this definition and would require a permit. There is a lot of flexibility in the incidental take permitting process otherwise there would be no fisheries for chinook and steelhead in the Columbia or Puget Sound. I think the problem with the Chambers Creek stock is not breeding introgression or an incidental take in the fishery. For steelhead it is clear that in the marine environment large numbers of smolts attract predators and at the smolt and the adult stage competition for food impacts growth and survival. Any recovery plan has to take in to account these density dependent factors when hatchery fish are involved.