Realize that many Chinook grow-up in near-shore waters; this & many other factors make them very different from all other Salmon species. For the most part, the commercial Troll fishery in SE Alaska (SEAK) is open year around, exposing Chinook from rivers south of Alaska to year-around harvest. There are size limits imposed, revival tanks must be used, & only single-point barbless hooks are required. From Oct-May they target "their" fish. When 50K of "treaty fish" (non-Alaska fish) are caught during this period, they get shut-down until the summer season. These 50K treaty fish count as part of their quota established by the "Abundance Index". From what I can tell the SEAK fisheries always overrun their quota while the BC fisheries underrun theirs.
If you took a look at the graph I posted earlier you wold see that only 3% of Chinook caught in SEAK are of Alaska origin. These fish are largely hatchery raised spring run Chinook that are marked by thermally altering a bone in their head.
http://wildfishconservancy.org/abou...d-fishery-chinook-catch-composition-1999-2010
The text is a good read if you are interested in conservation & click on the picture to enlarge it.
IMO the year-around SEAk fishery is a large reason we are seeing smaller Chinook:
They grow-up in this year-around fishery.
The older they are the larger they are (I know duh?)
The older they are they more time they are exposed to harvest.
If there is a genetic component to "large Chinook", then the gene pool is diminished
As far as misguided gloom & doom, we find out when the fish return when it's too late to act. So far dam counts on the Columbia show Spring & Summer Chinook counts to be below the 10 year average, as well as the fish being late.