I'm not arguing that we shouldn't. Worst case scenario is that it improves the quality of those streams but the grayling's do not return. That's still a win in my book. Just pointing out some of the trappings of restoration science. Various states have taken a lot of nifty approaches to introductions. Stream side farms and "trophy rivers" with various limits on season dates, tackle, and size limits have been very effective at establishing and growing populations of fish.