Gary -
Steelhead not only feed on different food items than coho and chinook they migrate to much different areas in the ocean. The steelhead seem to head offshore into the high seas directly. Steelhead are found throughout the north Pacific. The west coast steelhead have been found west of the international date line. In contrast the coho and chinook basically stay along the coast line and rarely migrate outside of the continental shelf.

There is little evidence of steelhead staying in the Sound rather than migrating to the ocean. Typically the only time one sees steelhead in the Sound is as they migrate to and from the rivers. That said rarely what has been termed "half-pounders" are see in our rivers. They are fish that returns to the river the same fall that migrate as smolts. With the fish returning within months of smolting it is hard to imagine them migrating very far off shore.

Tight lines
S malma