Symposium Abstract: Characterization of Coastal Great Lakes Benthic Habitat
S. J. Lozano, M. Blouin, and N. Wattrus
Colonization by dreissenid mussels, Dreissena polymorpha (Zebra) and Dreissena bugensis (Quagga), is one of the more ecologically important events to occur in the Great Lakes during the last decade. Since their introduction into the Great Lakes, dreissenids have colonized both soft and hard substrates to depths of 80 m and reached average densities of 40,000 mussels m-2 in the littoral zone. Because of high densities and widespread distribution, they have modified habitats for benthos and fishes and fostered growth and proliferation of non-indigenous species, such as the round goby and a Black Sea amphipod, Echinogammarus. In 2001, we used multibeam sonar to characterize the benthic habitat in Lake Michigan and acoustic remote sensing technology (sidescan sonar and acoustic bottom classification) to extend and extrapolate information on dreissenid distributions from spatially limited observations. These observations were combined with discrete in situ (video and SCUBA) observations in a geographic information system (GIS). We used this system to link dreissenid distribution with substrate type, morphology and depth. These data are critical inputs to modeling the ecological implications of dreissenid filtering on algal biomass and composition in the Great Lakes over changing environmental conditions.