Fish Habitat Use in the New Madrid Floodway

The New Madrid Floodway in southeast Missouri was created to divert part of the Mississippi River flow during catastrophic floods and thus alleviate flood risk on nearby population centers.  The Floodway extends from Birds Point, Missouri south to New Madrid, Missouri and encompasses the area between the Birds Point-New Madrid secondary levee and the Mississippi River primary levee. The surface area of the New Madrid Floodway is approximately 475 square kilometers. Prior to development, the New Madrid Floodway was dominated by bottomland hardwoods that periodically provided aquatic habitats used by fishes. This area has subsequently been cleared for agriculture related uses. As such, land use in the area is primarily agricultural with bottomland hardwoods and wetlands constituting the minority.  Since its creation, it was opened once during the extreme 1937 flood.  However, during 2011 the floodway was again opened and provided an unprecedented opportunity to evaluate the influence of floodplain inundation on fishes.  Specifically, we sampled the floodplain and the adjacent river at three stratified random locations (with replication) biweekly from the commencement of inundation (early June) through September.  We found that species richness and relative abundance was higher in the floodway then the main river. Our data supports many previous examinations that suggest floodplain inundation may be important for riverine fishes.