Exotic Bivalves Thrive in Deepwater

Ann Arbor, MI — Exotic bivalves, the zebra mussel and quagga mussel, apparently thrive well in deepwater of Lake Michigan - where the largest biomasses of burrowing amphipod, fingernail clam, and aquatic worms also occur.

Since 1999, researchers found that 1) exotic bivalves made up significant large portion of trawl catch from Lake Michigan at depths of 18-110 m and 2) biomass of bivalves often peaked at 27-46 m.

Average shell-free body weights of bivalves increased from low levels in shallow water, then increased to their maxima at 55-64 m, and then declined in deeper waters. Densities of quagga mussel larvae increased markedly from 2001 to 2003. Low stable water temperature at the thermocline, less wave action, and transport of food from shallow waters to deepwater are favorable factors that allow bivalves thrive, along with amphipods, fingernail clams, and aquatic worms. The quagga mussel thus is overtaking the zebra mussel as the dominant mollusk.

Original Publication Information

Results of this study, "Shell-free Biomass and Population Dynamics of Dreissenids in Offshore Lake Michigan, 2001–2003," are reported by John R. P. French III, Jean V. Adams, Jaquelyn Craig, Richard G. Stickel, S. Jerrine Nichols and Guy W. Fleischer in the latest issue (Volume 33, No. 3, pp. 536-545) of the Journal of Great Lakes Research, published by the International Association for Great Lakes Research, 2007.

Contacts

For more information about the study, contact John French, US Geological Survey - Great Lakes Science Center, 1451 Green Rd., Ann Arbor, MI 48105, frenchjrp@usgs.gov, (734) 994-3331.

For information about the Journal of Great Lakes Research, contact Marlene Evans, Editor, National Water Research Institute, 11 Innovation Boulevard, Saskatoon, SK, S7N 3H5, Canada; editor@iaglr.org; (608) 692-1076.

Links

Since 1967, IAGLR has served as the focal point for compiling and disseminating multidisciplinary knowledge on North America's Laurentian Great Lakes and other large lakes of the world and their watersheds. In part, IAGLR communicates this knowledge through publication of the Journal of Great Lakes Research, available to members in print and electronic form. A searchable archive of the journal is available online and includes the abstracts of articles from the journal's inception in 1975 through the most recent issue. In addition, complete articles are available to members who have signed up for an electronic subscription.