I know there are Channel cats in the Columbia as we caught them near the mouth of the John Day river , not sure what their range is in the big river though . Not sure what you meant by "what do you use carp bait for" ? I would imagine if you are asking what you can catch using their flesh for bait , then I would guess catfish as well as sturgeon and squawfish , and depending on the size of the bait who knows ??? When I was a kid and the method of take and bait restrictions werent what they are today , a guy could take chunks or srtips of meat off of chubs , whitefish and others and catch trout , panfish , bass and a few others . May not be on their top five list but it is still food for them .