Welcome to the interactive web schedule for the 2019 Midwest Fish & Wildlife Conference! Please note, this event has passed. To return to the main Conference website, go to: www.midwestfw.org.
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CONFERENCE SCHEDULE UPDATES & CHANGES: As a result of the prolonged government shutdown, we experienced a number of cancellations and changes to the schedule. Cancellations and changes are listed here (as of January 26, 2019).
AUTHORS: Jason L. Fischer, University of Toledo, Lake Erie Center; Edward Roseman, US Geological Survey, Great Lakes Science Center; Christine Mayer, University of Toledo, Lake Erie Center; Todd Wills, Michigan Department of Natural Resources, Lake St. Clair Fisheries Research Station
ABSTRACT: Artificial rock reefs have been used to remediate spawning substrates for lithophilic spawning fishes (e.g., Lake Sturgeon, Acipenser fulvescens;Lake Whitefish, Coregonus clupeaformis; and Walleye, Sander vitreus) in the St. Clair-Detroit River System. Early projects used species specific metrics (e.g., proximity to historic spawning locations) to guide reef placement. However, long-term success of some of the initial reefs was compromised by accumulation of fine sediments. Therefore, to improve the likelihood of successful reef function, project managers incorporated geomorphological criteria in 2013 to avoid placing reefs in areas near sediment sources and depositional zones. To evaluate the effectiveness of the revised placement process, we quantified physical maturation of artificial reefs using 1) annual down-looking and side-scan sonar surveys beginning in 2014 to measure reef areas and bottom roughness and 2) underwater video surveys beginning in 2015 to quantity sediment composition. Roughness of reefs constructed after 2013 remained greater than bottom roughness in areas adjacent to the reefs thru 2017, however, roughness of the Hart’s Light Reef was significantly lower in 2017 than in 2014, indicating some sediment accumulation. Similarly, sediment composition of the reefs remained similar thru 2017 and prevalence of reef rock was high, except at Hart’s Light Reef, where dreissenid mussel shells composed 32% of the substrate by age three. However, in 2018 reef rock was less prevalent at all reefs, due to accumulation of shells, fine sediments, and gravel. Despite the use of geomorphic criteria to identify areas most suitable for reef construction, sediment composition of the reefs has changed and long-term evaluation is required to determine if the changes observed in 2018 are temporary or representative of a longer trend. Nevertheless, our evaluation indicates future reef restoration projects could benefit by incorporating methods for maintenance, in addition to using geomorphic criteria to identify restoration sites.
