This study was conducted by:  Ian Stirling - Wildlife Research Division, Department of Environment, Department of Biological Sciences, University of Alberta Kristin L. Laidre - Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle Andrew E. Derocher - Department of Biological Sciences, University of Alberta, Edmonton Canada Rinie Van Meurs - Jastrzebia 201, 34-143 Lanckorona, Poland.