In terms of the known results of integrated hatchery steelhead programs, what is presented here is not accurate. While productivity of studied steelhead programs did almost universally decrease, abundance, with or without the programs was not measured or evaluated in most of the scientific papers that I have read. This would include the often cited Hood River studies which only looked at changes in productivity as well as the more recent studies of the reproductive success of steelhead in Little Sheep Creek, OR (Ewann A. Berntson, Richard W. Carmichael, Michael W. Flesher, Eric J. Ward & Paul Moran (2011): Diminished Reproductive Success of Steelhead from a Hatchery Supplementation Program (Little Sheep Creek, Imnaha Basin,Oregon), Transactions of the American Fisheries Society, 140:3, 685-698). Interestingly enough, in the study that most use to criticize integrated steelhead programs, those changes in population productivity in the Hood River where relatively low, estimated at only 8% at the population level versus a totally wild population.

Changes in abundance, with or without the programs have been hypothesized in various ways, from "back of the napkin" type calculations you see posted on internet fish sites, to more scientific modeling by independent groups such as the HSRG, Col. River ISAB, or ISRP. Those put together by the scientific groups tend to show increased adult abundance from these types of programs. Although to be clear, these results are modeling results. It should be noted that unlike differential productivity based on parentage analysis, you can only observe one population abundance number and if a hatchery program exists, that abundance will always include adults resulting from the hatchery program. A separate abundance excluding those hatchery fish cannot be observed in the same time frame. You therefore have to rely on either some modeled results or comparison between supplemented and representative unsupplemented populations for analysis of changes in abundance. Few statistically valid comparisons of population abundance such as Before-After Control-Impact (BACI) design studies as recommended by the ISRP have been conducted and those results have varied, but they do not show the reduction in "every single one" as suggested here. Taken as a whole across species, changes to abundance in supplemented populations rank in the middle (more than some and less than some) when compared to unsupplemented populations. This would lead to the conclusion that you can show no improvement from supplementation. This is the conclusion about supplemented populations reached by the ISRP. This is a completely different conclusion than wild fish, in every population (as suggested above) would be more numerous without the program. In terms of steelhead programs alone, I am aware of a couple of evaluations that have shown an increase in abundance (in one case, an increase in productivity as well) when compared to unsupplemented populations. One would be in BACI analysis of Umatilla steelhead using John Day steelhead as a reference population. The other would be the Hamma Hamma steelhead program in Hood Canal compared to three unsupplemented populations in the canal.

This is what a google search of the science as well as a thorough reading of the science will show. If anyone is aware of any more recent results, particularly statically valid reviews of changes in abundance, I am capable of learning.