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Tuesday, January 26 • 10:40am - 11:00am
Comparison of The Effects of Dreissenid Mussels on Native Virile Crayfish and Invasive Rusty Crayfish In Lake Michigan

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AUTHORS: Mael Glon*, Central Michigan University; Larson, E. R, University of Illinois Urbana-Champaign; Reisinger, L. S. , Pangle, K. L. - Central Michigan University

ABSTRACT: The Lake Michigan ecosystem has been dramatically altered by invasive species in the last several decades. Amongst these invaders, dreissenid mussels Dreissena polymorpha and D. rostriformis bugensis have been particularly large drivers of change, and research has suggested that these mussels may be facilitating the establishment of subsequent invasive species (i.e., invasional meltdown). The virile crayfish Orconectes virilis is native to the Great Lakes and has recently faced increased competition from and has widely been displaced by the invasive rusty crayfish Orconectes rusticus native to the Ohio River Drainage and introduced by bait bucket releases. Using a 30-day mesocosm experiment, we tested the hypothesis that rusty crayfish benefit more than virile crayfish from the presence of dreissenid mussels, and assessed if this effect is mediated by crayfish density. We also made behavioral observations to determine how mussel absence/presence and crayfish density affect habitat usage. We found that both species of crayfish grew more in the presence of mussels, and that growth of both species was higher at low densities. Overall, however, rusty crayfish grew and therefore benefited more from the presence of dreissenid mussels than virile crayfish. We also found that both species of crayfish were more active in the presence of mussels, with rusty crayfish being more active than virile crayfish in all cases. These results suggest that invasive mussels are disproportionately benefiting invasive rusty crayfish over native virile crayfish in Lake Michigan, which may be evidence of an invasional meltdown. Our study brings attention to the synergistic effects that benthic invasive species are having on Lake Michigan and will inform future studies on biological invasions and management efforts.

Tuesday January 26, 2016 10:40am - 11:00am EST
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