I can't remember the last time someone said that hatchery fish don't mingle with wild fish. I assume mingle means to spawn, which in this case that is a load of B.S. Of course hatchery fish spawn with wild fish! Anyone who thinks other wise needs a swift kick in the pants.

As far as my knowledge goes, there is no absolute statistic on hatchery-wild influence. It varies by river and by year. Idaho Fish and Game is conducting an extensive project on the influence of hatchery fish on wild genetics and ultimately the possibility of hatchery fish keeping "wild" populations afloat. This project is being done on spring chinook though, not steelhead. I'll wager that WA and OR have done a similar project in the past or are conducting one now through other projects.

There is almost no data on hatchery influence into Idaho steams with steelhead. I assume it is probably the same with WA and OR. Current data from one system in Idaho shows that in a stream considered 100% wild and native with no history of non-native steelhead introductions, there is about a 3-5% composition of adult hatchery fish per year attempting to spawn.