You can take it to the bank that most of the "rainbows" in rivers that offer
access to salt water are steelhead parr or (in the spring and summer)
smolts. While populations of resident rainbows have existed and continue
to exist in these rivers these populations are very small compared to the
temporary populations of young steelhead. Before being decimated by the 8,
12, 15, or even 20, trout limits allowed in years past, resident rainbow
formed an important part of the rainbow/steelhead complex since even the
progeny of resident rainbows may decide, at some point, to adopt an
anadromous lifestyle. It's quite possible that the apparent increase in
numbers of resident rainbow in some rivers (I've taken a few large ones in
the Snoqualmie while fishing for cutthroat and steelhead) is the result of
the residualization of hatchery steelhead plants. This was quite a common
phenomenon in some of the eastern Washington rivers like the Weatchee before
it was closed.
