Cooperative Fish and Wildlife Research Units Program: North Carolina
Education, Research and Technical Assistance for Managing Our Natural Resources

The robust redhorse (Moxostoma robustum) is a rare and imperiled, large catostomid fish found in only three regulated river drainages in the southeastern U.S. It has large pharyngeal teeth for crushing mollusks and other invertebrates known to sequester anthropogenic contaminants. The robust redhorse has been negatively affected by habitat modification and fragmentation from hydroelectric dams, introduced species, sedimentation, and water pollution and is protected by state endangered status in Georgia and North Carolina. Previous research by the authors and their students on physical instream habitat suitability has shown that habitat suitability will be enhanced by prescribed flow augmentations from hydroelectric dam releases; however, the impacts of water quality and contaminant loads remain unknown. In addition to the unknown effects of traditional organic and inorganic contaminants, recent research suggests that the impact of emerging contaminants, such as endocrine disrupting compounds, may be of significant detriment to fishes in the Pee Dee River. To further elucidate the impact and potential threat of water quality and contaminant dynamics on the robust redhorse, we proposed six research objectives to pursue in the Pee Dee River of North Carolina and South Carolina. We will (1) conduct systematic field sampling of habitat and food web components, (2) conduct experimental field bioassay exposures with captively-propagated fish, (3) perform laboratory analyses of traditional and emerging contaminants (4) determine aquatic food web structure, (5) develop population and food web models to describe effects of habitat and water quality modifications, and (6) synthesize results for robust redhorse recovery from population and ecosystem perspectives. This research is unique in that it will yield results and inference that are descriptive (systematic sampling), explanatory (experimental bioassays, food web analyses), and predictive (population and food web modeling) at multiple scales and across disciplines to inform decision making and management. If the proposed research is funded and conducted, it will guide management objectives and goals for species recovery and habitat restoration.