1. Division of Biology, Kansas State University, Manhattan, Kansas 66506 USA
2. Department of Fish, Wildlife and Conservation Biology, Colorado State University, Fort Collins, Colorado 80521 USA
3. University of Maryland Center for Environmental Science, Appalachian Laboratory, Frostburg, Maryland 21532 USA
4. Center for Reservoir and Aquatic Systems Research, Department of Biology, Baylor University, One Bear Place 97388, Waco, Texas 76798-7388 USA