2011 Northern Fur Seal Pup Production Estimate on Bogoslof Island, Alaska
Northern fur seal pup production numbers estimated for Bogoslof Island during August 2011.
Numbers of northern fur seal, Callorhinus ursinus, pups were estimated using a mark-recapture method, shear-sampling, on Bogoslof Island (Figure 1) during August 2011. We estimated that 22,905 (SE = 921.5, Table 1) pups were born on Bogoslof Island. Dead pups were counted on all breeding areas of Bogoslof Island resulting in an observed pup mortality rate of 2.6%. The 2011 pup production estimate for Bogoslof Island is 30.3% greater than the estimate in 2007 (Figure 2). Since the first pup was observed on Bogoslof Island in 1980 pup production has increased at an annual rate of 38.2% (SE = 2.60) and at an annual rate of 11.7% (SE = 0.90) since 1997.