Chapter 3 North Carolina Species
suggesting that diversity of North American mussels has been underestimated. Taxonomic difficulties have yet to be resolved for several genera, most notably the Elliptio . There is an extreme knowledge deficit regarding the pea (or fingernail) clams in North Carolina, primarily in the Family Sphaeriidae. Attaining information on their distributions should be pursued whenever possible. Protecting a rich fauna of mussels from environmental contamination requires an understanding of mussel sensitivity to diverse toxicants. The vast majority of mussel species remain untested for most toxicants, and estimating safe environmental concentrations is a critical need, especially for the protection of rare, threatened, or endangered species. Freshwater mussel toxicology still lacks full identification of pollutants that may limit mussel survival, recruitment, and recovery. Few of the compounds that mussels encounter in the wild have been evaluated in the lab. Also, toxicity tests seldom address mussel reproduction, and tests are still short relative to mussel lifespans. In particular, there is a need to test previously unevaluated contaminants of emerging concern using long-term exposures that more closely mimic natural conditions, and to evaluate more ecologically relevant endpoints such as mussel health and recruitment. Several publications over the last decade have noted the absence or under-protectiveness of national water quality criteria for particular pollutants to which mussels are known to be sensitive (Augspurger et al. 2003; Wang et al. 2010; Haag and Williams 2014; Haag 2012) . To facilitate habitat evaluation, work is needed to better characterize chemical and contaminated sediment exposure and provide benchmarks to define acceptable pollutant concentrations. Researchers at NC State University, University of Georgia, and US Geological Survey have started work on testing additional classes of chemicals (Bringolf et al. 2010; Hazelton et al. 2012, 2013; Wang et al. 2012) . The US Environmental Protection Agency (USEPA) has been an active participant in designing and funding these studies, but more are needed. Publication of recommended benchmarks for pollutants of concern (e.g., metals, major ions) will be useful in developing water quality regulations. 3.6.5 Management Needs Restoring mussels into areas where they have been extirpated is a high priority where degraded habitat is being reclaimed and restored in some watersheds. Propagation and release of mussels to augment existing populations will help reduce the risk of extinction and may increase genetic diversity among small populations. It will be important to understand how dispersal limitations of larval hosts affect connectivity of mussel communities (Newton et al. 2023) . Removing barriers and other impediments to host fish movement will allow natural recolonization of suitable habitats and facilitate gene flow between populations. Freshwaters that support populations of SGCN mussels must be monitored to detect changes in water quality. Water quality ratings (poor to excellent) determined by the NC Department of Environmental Quality (DEQ), Division of Water Resources (DWR) Waters Sciences Section
2025 NC Wildlife Action Plan
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