We conducted a study of channel catfish (Ictalurus punctatus) movements in the Yockanookany River, Mississippi, a river subjected to a long-reach decoupling of the river channel from its respective floodplain. We collected 40 channel catfish and surgically implanted radio-transmitters. Fish were tracked during 2 periods—March-June 1994 and November 1994-June 1995. Most fish moved ≤5 km. During elevated flows, radio-tagged fish in the river moved to or remained in the river section coupled with the floodplain. Four fish moved from the river channel into an oxbow lake when it was coupled with the river by high water. While we recognize the importance of addressing floodplain river ecosystems at a landscape and system level of resolution, and absolutely support management at this scale, our study indicates that 5-km channel sections should be considered the minimum management unit for channel catfish in small Mississippi rivers.