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Author ORCID Identifier


Campus-Only Access for One (1) Year

Document Type


Degree Name

Doctor of Philosophy (PhD)

Degree Program

Environmental Conservation

Year Degree Awarded


Month Degree Awarded


First Advisor

Allison Roy

Subject Categories

Terrestrial and Aquatic Ecology


The brook floater (Alasmidonta varicosa) is a freshwater mussel (Order: Unionida) native to Atlantic Slope drainages from Canada (Nova Scotia and New Brunswick) to Georgia, U.S. The precipitous loss of brook floater populations and extant low densities in many regions evokes an urgency to establish conservation initiatives for the species. A targeted approach to population restoration is critical in Massachusetts (MA) where brook floater remain in low abundances in only 4 of the 11 originally occupied watersheds (Hydrologic unit code-12). A succinct strategy to restore a rare freshwater mussel species is unavailable yet critical to aid restoration. The overall goal of my dissertation was to provide information essential for brook floater population restoration. In my dissertation, I focus on key aspects of population restoration that include propagation, habitat, and juvenile growth and survival. To propagate brook floater, I evaluated host fishes that maximized juvenile production in a laboratory. Brook floater glochidia metamorphosed on all fish species (ten in six families). Although brook floater glochidia can metamorphose on many different fish species, relative metamorphosis success was variable among species and may depend on fish collection location. To understand brook floater riverine habitat, I sampled 25 sites in 9 watersheds across MA. Habitat features within mesohabitats predicted brook floater abundance and indicate mussels are dependent on small particle sizes likely supportive of burrowing. To understand the range of brook floater growth rates and how they relate to water quality within the four rivers with brook floater in MA, I deployed two cohorts of juvenile brook floater in contained systems and related growth and survival to water quality. Mussels had uniformly high survival across the four rivers, but total growth differed among rivers and growth rate was negatively affected by multiple diffuse stressors. In the last chapter I developed a framework for locating habitat to support species reintroduction that could be applied across different taxa. Results from this dissertation are integral to aid decision-making on brook floater restoration in MA. Moreover, this dissertation provides a blueprint for population restoration steps to consider for any rare mussel.


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Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.