Assessment of the freshwater mussel community of the tidal-freshwater Anacostia River

Ashton, Matt; Sullivan, Kyle

This report details the work conducted by the Maryland Department of Natural Resources on behalf of the Anacostia Watershed Society to assess the freshwater mussel community in the tidal‐freshwater Anacostia River. The goals of this project were to 1) determine the number and distribution of freshwater mussels in the tidal Anacostia River, 2) contrast patterns of their abundance with abiotic variables, and 3) outline the need for future work and a framework for their restoration. Due to the low number of mussels collected, we did not correlate patterns of presence or abundance with abiotic variables or extrapolate ecosystem service parameters of mussels to population and river‐wide estimates. Instead, habitat data collected at sample locations are provided in Appendix II. The Department surveyed for freshwater mussels during October of 2016 within the Anacostia and Potomac rivers with a standard PONAR dredge to determine and compare mussel populations. The intertidal habitat of Kingman Lake was surveyed by visual and tactile searches to better understand its function as a potential refuge and the mussel community in the Anacostia River. Three individuals of two freshwater mussels species were detected in 54 samples from the Anacostia River. Fifteen individuals of four species were detected in 15 samples from the Potomac River. We observed six species of live or dead freshwater mussels in Kingman Lake and along its shoreline at low tide. Although only a few individuals of each mussel species were found in the Anacostia River, the current representatives of the mussel community largely reflect the historic community. However, the current community was primarily composed of habitat and host generalist species, which may indicate a shift in community composition over time due to environmental disturbance. Strategies for mussel population and community restoration are discussed, which vary in their objectives (biomass vs. biodiversity) and resource needs (propagation vs. host infestation). Further survey work should be considered to better understand the size, extent, and community composition of mussel population in the Anacostia River, Kingman Lake and similar habitats to inform conservation planning.

Assessment of the freshwater mussel community of the tidal-freshwater Anacostia River

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