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Freshwater Mussel Research and Monitoring for the Penobscot River Restoration Project
Abstracts:
Dwarf Wedgemussel (Alasmidonta heterodon) Relocation and Monitoring for the Removal of the Homestead Woolen Mill Dam on the Ashuelot River (Swanzey, New Hampshire)
Ethan Jay Nedeau, Biodrawversity
The removal of the Homestead Dam in the Ashuelot Riv¬er in 2010, and concurrent reinforcements to the bridge located just upstream from the dam, affected instream habitat for freshwater mussels throughout the nearly 4.25-mile long impoundment. The federally endangered dwarf wedgemussel (Alasmidonta heterodon) had been documented throughout the impoundment. Although some mortality ("take") was inevitable and expected, it was hoped that most mussels that were not relocated prior to or during dam removal would migrate downslope as water levels fell, and ultimately establish stable and resilient mussel populations. The anticipated long-term positive effects of dam removal on mussel populations and ecosystem health were recognized as an additional benefit of a project whose primary goal was to improve fish passage. There were three elements of this project. First, mussels were relocated to minimize mortality. Second, post-removal monitoring of tagged mussels was conducted to evaluate the success of relocation. Third, a post-removal quantitative mussel study helped to establish new baseline population and habitat data in the former impoundment. Biodrawversity biologists and volunteers collected and relocated 496 dwarf wedgemussels prior to and dur¬ing construction work in 2010, of which 253 were tagged and monitored in 2012. A 2012 quantitative mussel and habitat survey in the former impoundment demonstrated that the anticipated long-term benefits of dam removal on instream habitat and mussel populations was still not realized, and surviving mussels were still transient because of patchy and unstable habitat. This project yielded several interesting insights into the effectiveness and logistical challenges of recovering mussels during dam removals, and into the potential short-term and long-term effects of dam removals on rare mussels and their habitat.
Freshwater Mussel Research and Monitoring for the Penobscot River Restoration Project
Ethan Jay Nedeau, Biodrawversity
George Aponte Clark, Penobscot River Restoration Trust
The Penobscot River Restoration Project is one of the largest and most creative river restoration projects in our nation's history. In 2012, the Great Works Dam and an older submerged "legacy dam" were removed, marking major milestones in the historic effort to restore fish habitat and aquatic connectivity in the Penobscot River. Biodrawversity worked with the Penobscot River Restoration Trust to develop and implement an Incidental Take Plan (ITP) for two state-listed mussel species known to occur upstream and downstream of the Great Works Dam: yellow lampmussel (Lampsilis cariosa) and tidewater mucket (Leptodea ochracea). One element of the ITP was a quantitative study of the mussel assemblage in the entire impoundment before and after dam removal. A second element was a quantitative study of mussel assemblages in three monumented plots (25x50 meters) in the impoundment before and after dam removal. A third element was relocation of mussels before and during the dam removal process; yellow lampmussels and tidewater muckets were tagged and moved to stable areas of the former impoundment, and monitored during and after dam removal. In 2013, the Veazie Dam and associated legacy structures were also removed. During this dam removal, yellow lampmussels and tidewater muckets were collected and moved to stable areas of the former impoundment.
Biography:
Ethan Nedeau is the Principal at Biodrawversity. In the past 18 years, Ethan has led more than 300 field projects in the northeastern United States, focusing primarily on freshwater mussels and other aquatic macroinvertebrates. In total, Ethan has surveyed nearly 900 waterbodies, sampled more than 7,000 survey sites, and handled more than 30,000 specimens of state-listed or federally listed freshwater mussel species. His projects have spanned a wide range of objectives, including basic research on endangered species populations; inventories and baseline data collection; consultation for projects related to transportation infrastructure, transmission lines, pipelines, water withdrawals, dam removal, and river restoration; relicensing and compliance monitoring for hydropower companies; and pollution assessment. Ethan wrote, edited, designed, and illustrated numerous environmental publications, including four frequently cited publications on the freshwater mussels of Maine, Connecticut, the Connecticut River watershed, and western North America.