Meeting Abstract
77.1 Sunday, Jan. 6 Contrasts in Byssal Thread Attachment of Zebra versus Quagga Mussels: Implications for Habitat Expansion Constraints PEYER, S.M.*; MCCARTHY, A.J.; LEE, C.E.; University of Wisconsin-Madison smpeyer@wisc.edu
While the invasive zebra mussel has rapidly spread throughout the Great Lakes and inland waterways since their introduction, quagga mussels have been slower to expand their range. However, quagga mussels are displacing zebra mussels in shallow habitats, but to a lesser extent in areas of high water flow. Might zebra and quagga mussels have functional differences that could explain differences in colonization and persistence patterns? We hypothesized that zebra mussels have (1) a higher rate of byssal thread attachment, (2) greater byssal thread strength, and (3) lower detachment in the face of fluid flow, relative to quagga mussels. These factors might explain the persistence of zebra mussels in wave exposed habitats. Thus far, we examined byssal thread synthesis rate and detachment from substrate of both species exposed to water velocities of 0, 50, 100, and 180 cm s-1. We allowed mussels to attach to the walls of a closed system flume for 24 hours and then exposed them to each of the velocity treatments for 8 hours. After the 8-hour exposure period we dissected the mussels to determine the total number of byssal threads produced during the experimental period. Thread synthesis rate of zebra mussels increased significantly from lower to higher water velocities, but did not increase for quagga mussels. Detachment from the substrate increased for both zebra and quagga mussels with increasing water velocities, but at a much higher rate for quagga mussels. Faster rate of byssal thread synthesis by zebra mussels might be a factor that minimizes their detachment from hard substrate at high water velocities. This difference between zebra and quagga mussels might partly account for the ability of zebra mussels to maintain their dominance in habitats with higher fluid flow.
