The primary goals of this proposed project are to help identify and prioritize threats to endangered mussels and to determine whether existing environmental concentrations of ammonia, copper, and major ions in sediment pore-water are contributing to the decline of native mussel populations, as indicated by recent laboratory toxicity tests. These goals are consistent with the needs identified in the National trategy for the Conservation of Mussels, particularly to “increase coordination and information exchange among entities that study, manage, harvest, conserve, or recover native freshwater mussels”; and “determine how various perturbations impact mussels and their habitat, and provide managers with the information needed to minimize or eliminate threats and protect quality mussel habitat”. Also, consistent with the Service’s Strategic Habitat Conservation approach, we are using information from the Mussel Threats Geospatial Database (Database) to design this study, will enter our results into it upon completion of the study, and use our results to recommend management actions—forming an adaptive management feedback loop and presenting results in a transparent manner, while involving the following components: assessment, goal setting, conservation delivery, monitoring, and information management.
To accomplish these goals, this project has the following objectives:
- Work collaboratively to identify and prioritize threats to freshwater mussels using the Ecological Risk Assessment framework, and add information to the Database. Consolidate available data, and demonstrate mussel threats in an easily assessable and interpretable manner.
- Collect pore-water samples and gather available data to compare measured concentrations of ammonia, copper, and major to toxicity thresholds determined in laboratory studies and determine where exceedances occur. (The availability of recent surveys and ability to coordinate with planned surveys will be considered in site selection).
- Collect pore-water and overlying water samples and gather available data to determine the relationship between measured concentrations of ammonia, copper, and major ions and local distributions of mussels in the field.
- Determine the relationship between pore-water and overlying water concentrations of ammonia, copper, and major ions at each site. While glochidia, their host, and adult mussels are more commonly exposed to overlying water, juvenile freshwater mussels are burrowed within the sediment and are exposed to pore-water. However, water quality monitoring samples are typically collected only from the overlying water. Therefore, relationships between pore-water and overlying water concentrations must be established to translate overlying water concentrations used in typical water quality monitoring into pore-water concentrations that are relevant to the most sensitive life-stage of mussels.
- Share results and appropriate management recommendations with Service biologists working on mussel recovery and conservation plans, ESA section 7 consultations, and mussel restoration; with U.S. EPA, state and tribal agencies that are setting water quality criteria and standards and issuing permits; and with conservation partners working on mussel protection and reintroduction. Results will be entered in the Midwest Regional Freshwater Mussel Threats Geospatial Database.
