Cooperative Fish and Wildlife Research Units Program: Massachusetts
Education, Research and Technical Assistance for Managing Our Natural Resources

The Brook Floater (Alasmidonta varicosa) is a stream-dwelling freshwater mussel (Bivalvia, Unionoida), native to the Atlantic Slope of the United States and Canada and has experienced significant population declines throughout its range. The species’ distribution has been restricted to approximately 50% of its historic sites, and local population declines have been observed from Nova Scotia to Georgia. Identified threats include decreased habitat and water quality associated with shoreline and watershed development, habitat fragmentation caused by dams and stream crossings, and potential stochastic events associated with a changing climate. This species has been identified by Northeastern states as one of the most critically imperiled species in the region and was one of the few mussel species identified as “At-Risk” by the US Fish and Wildlife Service in 2021. A range wide, collaborative approach to conservation is needed to reverse the trend of habitat loss and reduce the risk of local and regional extirpations. A nationally competitive State Wildlife Grant involving four funded states was awarded to address this issue. To assist in the coordination of this project, and to serve as a technical lead on project activities, the Natural Heritage and Endangered Species Program (NHESP) of the Massachusetts Division of Fisheries and Wildlife (MassWildlife) has partnered with the Massachusetts Cooperative Fish & Wildlife Research Unit at the University of Massachusetts, Amherst (UMass).

To increase rangewide cooperative conservation efforts and strategic planning towards reducing further population losses and defining approaches for recovery of Brook Floater throughout the species’ range from Georgia to Nova Scotia. UMass will assist in mussel surveys and habitat assessments to evaluate responses to dam removals for mussel (SGCN) species of greatest conservation need, develop pre-stocking and post-stocking mussel monitoring and habitat assessment protocols to identify and track introduced Brook Floater populations, perform rapid mussel and habitat assessments in Massachusetts and Connecticut to update mussel SGCN distributions, develop multi-species occupancy and detection models using reach- and landscape- scale covariates, and help to maintain the Brook Floater Working Group. Our hope is that State partners will utilize approaches and information outcomes of this grant to assess and maintain populations of Brook Floater and other SGCN using an Adaptive Management Framework and prioritize site-specific actions that will prevent further declines of Brook Floater.