Meeting Abstract

P1.53  Jan. 4  Quantifying Zebra and Quagga Mussel Performance on Hard versus Sedimentary Substrates using a Random Walk Analysis PEYER, S. M.*; HERMANSON, J. C.; LEE, C. E.; University of Wisconsin-Madison, Madison, WI; USDA Forest Products Laboratory, Madison, WI; University of Wisconsin-Madison, Madison, WI smpeyer@wisc.edu

While the zebra mussel Dreissena polymorpha ranks among the most costly and environmentally destructive invasive species in North America, the quagga mussel Dreissena bugensis might pose even greater threats to ecosystem integrity. Quagga mussels are displacing zebra mussels on shallow, hard substrates and demonstrate greater propensity to colonize deep, sedimentary substrates. Few studies have focused on range expansion constraints of quagga mussels relative to zebra mussels. Although sedimentary substrates are reported to pose physical barriers for colonizing mussels because of their instability, greater variation in shell shape might give quagga mussels a competitive advantage over zebra mussels. Specifically, the deep quagga mussel shape has been speculated to be functionally adapted for living on unstable sediment. However, there has been no quantitative analysis of the functional consequences of shape variation. We examined movement of deep and shallow quagga mussels, and zebra mussels of various sizes on both hard and sedimentary substrates using time-lapse imaging at a rate of 1 frame per minute for 24 hours. A random walk analysis of the paths generated from the time-lapsed images enables us to compute diffusivities and entropies, thereby providing a quantitative means for comparing locomotory performance of the three types of mussels.