1. Washington Cooperative Fish and Wildlife Research Unit, School of Aquatic and Fishery Sciences University of Washington Seattle Washington USA
2. Applied Physics Laboratory Polar Science Center, University of Washington Seattle Washington USA
3. Marine Mammals Management United States Fish and Wildlife Service Anchorage Alaska USA
4. United States Geological Survey Eastern Ecological Science Center Laurel Maryland USA
5. United States Geological Survey, Washington Cooperative Fish and Wildlife Research Unit, School of Environmental and Forest Sciences and School of Aquatic and Fishery Sciences University of Washington Seattle Washington USA