1. Department of Fisheries and Wildlife; Michigan State University; 480 Wilson Road East Lansing Michigan 48824 USA
2. U.S. Geological Survey; Great Lakes Science Center; 1451 Green Road Ann Arbor Michigan 48105 USA
3. Department of Biological Sciences; State University of New York-Oswego; Centennial Drive Oswego New York 13126 USA
4. Department of Environmental Sciences; University of Toledo Lake Erie Center; 6200 Bayshore Road Oregon Ohio 43616 USA