i agree with ryan 100%. though i didn't spend a lot of time on local flows this year for coho, close friends of mine managed 2 to 4 hatchery fish on nearly every outing. these guys fish blades and bait and are hardcore anti flossers. I was starting to get sick of seeing pics and hearing thier reports so i did put some time in at the tail end. for 4 days on the water (1 vedder/3 suicide) i killed 5 hatchery, released 6 wild and 2 boots and lost 4 that appeared to be coho. hooked only 7 chum.
i've been fishing these rivers for over 18 years and even though they change shape, if the coho are there it's only a matter of changing up your presentation and drift choice until they bite.
take the chehalis for example.... a few years ago we would get there long before first light to be the first guys in one of the "glory" holes. That first 20 mins of fishable light was the key, nice little ball of roe with a tiny white yarn and it was coho one after another.... then nothing. that's when the switch came for #3 nickel or gold colorados, fished just below the chums... and bang bite on again for a little while the nothin. that's about when we'd pack up and head er home, limits of hatchery coho all around. we would be leaving the hole by 1 1/2 after sunrise, guys looking at us in disgust because the vast majority of them hadn't caught anything but chums.
Applying this tactic on the chehalis was a sure fire bet as long as the conditions were right and the fish were present. Every flow will be different and of course every years fish numbers will vary but cycling through your gear, especially at first light is key to getting otherwise non biting fish to aggresively turn on.
that's what's worked for me, not saying it's the holy grail of advice though