1. Department of Environmental Conservation; University of Massachusetts; Amherst MA 01003 USA
2. Division of Biological Sciences; University of Montana; Missoula MT 59812 USA
3. USDA Forest Service; Rocky Mountain Research Station; Missoula MT 59801 USA
4. Silvio O. Conte Anadromous Fish Research Center; United States Geological Survey; Turners Falls MA 01376 USA