1. University of North Carolina at Chapel Hill, Institute of Marine Sciences, Morehead City, NC 28557, USA.
2. National Marine Fisheries Service, National Oceanographic and Atmospheric Administration, Alaska Fisheries Science Center, Auke Bay Laboratory, Juneau, AK 99801–8626, USA.
3. Centre for Wildlife Ecology, Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC, Canada, V5A 1S6.
4. U.S. Geological Survey, Alaska Science Center, 1011 East Tudor Road, Anchorage, AK 99503, USA.
5. U.S. Department of Interior, Fish and Wildlife Service, 1011 East Tudor Road, Anchorage, AK 99503, USA.