Spatial Patterns of Fish Assemblages in Bear Creek Watershed, Mississippi

Oxbow lakes form isolated aquatic fragments on floodplains and retain differing degrees of connectivity to neighboring rivers. Maintenance of both lacustrine and rheophilic fish communities in oxbow lakes is intrinsically dependent on the hydrologic landscape. We explore how hydrologic connectivity shapes fish communities in the Bear Creek watershed in central Mississippi. Bear Creek, located in the former channel of a disjoined river bed, spans the entire watershed and is characterized by five on-channel lakes. Additionally, numerous other oxbow lakes are located throughout the watershed, and range in succession and connectivity to the creek.  Fish collections, made with electrofishing in 2006-2012, were examined with indirect gradient analysis which indicated that on-channel lakes (n=5) had similar fish communities and were characterized by rheophilic species. Conversely, fish communities in off-channel lakes (n=8) often exhibited strong dissimilarities among themselves and were distinguished from on-channel lakes by the dominance of lacustrine species. From a fishery management perspective, our survey suggests a diversity of fishing opportunities are provided by the diversity of fish assemblages, and that off-channel lakes offer the greatest potential for management involvement.