The way I understand it is, its the residence fish you dont want to eat. Salmon and Steehead are migratory therefore they are not in the river long enough to become contaminated, contamination rests in the body fat of the fish. I generally fillet fish that I kill trimming belly fat from the fillet. Sturgeon are also migratory and travel to and from the ocean. You can tell a sturgeon that hasn't been in the river very long, this is the fish I kill if I kill one. Sturgeon above the falls should be considered resident fish, They can't travel through the fish ladder, so they can't be considered migratory. When I start exploring the upper Willamette for Sturgeon, this will be a catch and release fishrie from my boat.