JJ,
All of the Puget sound rivers have had low returns of fish the last 5 years, wild fish included and the rivers in Oregon, California, and sourthwest Washington have had good returns. Only a few years ago the rivers of California had very bad returns of steelhead. Also, B.C. rivers have had poor returns of steelhead the last few years. Therefore, the low returns are a systemic problem spread over a very large area and probably due to ocean conditions or the salmon farms in the Straight of Georgia.
I didn't say anything about residualizing or straying. I said that according to the DNA studies Steve Stout the manager of the Marblemount Hatchery told me about, there was only a 0.01% probability of hatchery/wild interaction on the Skagit, Sauk, and Cascade rivers. I also said Steve told me there was not a lot of steelhead spawning happening below Concrete and that the majority of steelhead spawn in the Sauk.
I am aware of the wild steelhead returns to several of the creeks in the middle river. However, these are either miles downstream of Grandy Creek or some distance upstream of Grandy Creek. Presitin Creek in the closest one and it is around 2 miles upstream. Therefore, there seems to be little likelihood of wild/hatchery spawning interaction.
I've not caught a residualized steelhead (rainbows) in the Skagit system, nor have I met anyone who has. This doesn't mean they don't exist; but it does mean they are rare. I don't see a facility at Grandy Creek adding much if anything to the small number of residualized steelhead (rainbows) in the river.
There is no documented hatchery steelhead strays that I am aware of in Bacon Creek, Day Creek, Gilligan Creek, Presitin Creek, Jackman Creek, Swift Creek, Illabot Creek, Loretta Creek, or Finney Creek all of which have been extensively surveyed by the Skagit System Cooperative for the presence of wild and hatchery steelhead. Therefore, although straying is a possibility, it appears to be a very, very low possibility.
MMM,
Steelhead are able to spawn in a seasonal stream, have the eggs hatch, and the egg-sack fry survive by moving down to a larger body of water all in a 3 week time frame with the seasonal creek becoming dry almost at the moment the fry make it to the larger water. It is amazing what steelhead can do.