1. Alaska Cooperative Fish and Wildlife Research Unit, College of Fisheries and Ocean Sciences University of Alaska Fairbanks Fairbanks Alaska 99775 USA
2. U.S. Geological Survey, Alaska Cooperative Fish and Wildlife Research Unit, Institute of Arctic Biology University of Alaska Fairbanks Fairbanks Alaska 99775 USA
3. International Arctic Research Center University of Alaska Fairbanks Fairbanks Alaska 99775 USA
4. U.S. Fish and Wildlife Service, Anchorage Conservation Office Anchorage Alaska 99503 USA