1. Department of Fisheries and Wildlife, Oregon State University, Corvallis, Oregon, USA
2. Environmental Science Program, Pacific University, Forest Grove, Oregon, USA
3. Oregon Department of Environmental Quality, Portland, Oregon, USA
4. Oregon Cooperative Fish and Wildlife Research Unit, Oregon State University, Corvallis, Oregon, USA
5. Biological Resources Division, U.S. Geological Survey, Corvallis, Oregon, USA
6. Biological Resources Division, U.S. Geological Survey, Columbia River Research Laboratory, Cook, Washington, USA