Meeting Abstract

P1.54  Jan. 4  Comparing byssal thread properties of Dreissena polymorpha and Dreissena bugensis in turbulent conditions MCCARTHY, A.J.*; PEYER, S.M.; LEE, C.E.; Univ. of Wisconsin, Madison; Univ. of Wisconsin, Madison; Univ. of Wisconsin, Madison ajmccarthy@wisc.edu

The zebra mussel (Dreissena polymorpha) ranks among the most costly and ecologically destructive invasive species in North America. A congener of the zebra mussel and more recent invader, the quagga mussel (Dreissena bugensis), is now displacing the zebra mussel in shallow habitats of the Great Lakes. However, there is anecdotal evidence that zebra mussels still maintain dominance in areas of higher water velocity or wave exposure, suggesting possible hydrodynamic limits to quagga mussel range expansion. Differences in byssal threads, which are secreted by the foot for attachment to hard substrate to prevent dislodgement, might help explain in situ observations of zebra and quagga mussel distributions. We compared byssal thread production and strength of attachment between the two species following exposure to three different intensities of turbulence and water velocity. Machine-based image processing was used to quantify byssal thread production and attachment location, and areas of the adhesive plaques. Tensile tests indicated any differences in mechanical properties of the byssal threads between the two species. To date, competitive interactions between these two highly invasive species has received little attention. This study will help reveal whether quagga mussel expansion and displacement of the zebra mussel within the Great Lakes is limited by byssal thread attachment production and strength in turbulent habitats.