Well said SG. I was trying to infer that just because someone writes a scientific paper, it should not be taken as the gospel. Trying to make concrete conclusions from statistical analysis is a flawed approach. One sentence in that paper that struck me as bold was "the proportions of wild steelhead also declined over time because of the increase in the proportion of hybrid individuals". Like you said, there is no black and white. Just too many variables. Thanks for your info.