If bass (assumed you mean Largemouth Bass) present in high numbers, then it is likely Channel Catfish recruitment is being blocked by depredation by bass on the Channel Catfish fry once they leave nest and fingerlings once the leave the father's care. The smaller 4" to 10" bass have little trouble rushing in to snatch fry even with male catfish trying to defend the schooling brood. The surviving fingerlings, if any, would then be running a gauntlet of bass that have to be only half again as long to eat the catfish fingerlings. The Channel Cat's are not good at using cover.

You could restore recruitment, assuming breeders have not aged out, by culling the Largemouth Bass hard. The larger Bluegill can eat catfish fry as well but I doubt they will actually fill up on them like bass are inclined to do.