Maybe yes and maybe no on the late coho. When WDF set up the coho escapement goals, at least in PS, they quantified the escapements with surveys through 12/31. On Clinton's first inauguration, January of 1993, I think, more than 200 coho went up Soos Creek on a spate. But, the December and January net fisheries have likely hammered them, too.

Especially in the face of intense fisheries of any kind remember that what spawns is what is not caught; non-biters, odd-timed returns, smaller (or larger) than net mesh, and so on.

Jeff Cedreholm, who worked for DNR and primarily on the coast, was convinced that the early returning steelhead spawned in the tributaries. Which means that intense early fisheries eliminated them. Since steelhead rear for a year or more in the stream, loss of tributary spawners means loss of tributary production. Back when I was working, this was conformed by loss of trib spawners in intensively fished waters like the Green.