This may sound freaky.
I think I know which river you are floating. I've had a couple of reports and they said the only thing they are getting fish on was red GP's 1/0 -3/0. I know sounds freaky weird but worth a shot. I would guess you are putting in at the dam and taking out at the g... ......... (as you didn't mention the river it I won't, I know I get tick when people talk about the big one north). What are the water temps? I would personally try something small with movement and flash (very little).
best of luck and let us know