The Importance of Shallow, Low-Velocity Habitat to Juvenile Fish in the Middle Mississippi River

Habitat management is a crucial aspect of fisheries management.  Without knowledge of habitat utilization, fisheries scientists are unable to effectively make habitat manipulation recommendations.  This becomes especially prominent when trying to conserve sportfish and protect threatened and endangered species.  To determine juvenile fish and their habitat associations in the Middle Mississippi River (MMR), we analyzed mini-trawl catch data of six juvenile fish species: Blue Catfish (Ictalurus furcatus), Channel Catfish (Ictalurus punctatus), Channel Shiner (Notropis wickliffi), Freshwater Drum (Aplodinotus grunniens), American Paddlefish (Polyodon spathula), and Shovelnose Sturgeon (Scaphirhynchus platorynchus).  The data set contained 2,500 mini-trawl sampling efforts conducted between 2002 and 2013, resulting in the capture of roughly 22,000 target specimens.  Catch per unit effort (CPUE) was evaluated by mesohabitat (i.e., velocity, depth, and substrate).  Overall, these data suggest that juvenile fish species are more prevalent in shallow water and slower velocities.  Ultimately the information garnered during this evaluation should be incorporated when considering habitat modifications, especially those modifications that impact the availability of shallow-low velocity habitats.