Evaluation of Growth and Survival of Three Freshwater Mussel Species at Sites Targeted for Population Restoration in a North Carolina River

In North Carolina, wavyrayed lampmussels (Lampsilis fasciola) and spike (Eurynia dilatata) currently are state species of special concern, and rainbow mussels (Villosa iris) are state threatened. As a result of extensive conservation and management efforts, recovery of suitable habitat and im- provements in water quality have made mussel restoration a possibility in the Oconaluftee River within lands owned by the Eastern Band of Cherokee Indians. As part of restoration efforts, we introduced propagated or translocated individuals of these three species into the Oconaluftee River. Individu- als were marked and stocked at four sites as either free-living specimens or within silo enclosures, and monitoring took place over one growing season (April to October 2019) to record survival and growth. In addition, we included data from mussels in silos remaining on three of our four sites from a previous feasibility study. Survivorship of stocked mussels during the study period was 98.3% for wavyrayed lampmussels, 96.6% for spike, and 96.6% for rainbow mussels. Additionally, we detected growth for all species, though it differed among sites with individuals growing least at the most upstream site for both the wavyrayed lampmussel and rainbow mussel. Free-living individuals grew faster and suffered less valve damage than those held in silos. This information is useful to guide study design for further mussel restoration efforts and feasibility studies both in the Oconaluftee River drainage and in other high-gradient systems.

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