Winter distribution and abundance of crabeater seals off George V Land, East Antarctica

Abstract

This study is the first to describe the winter distribution of crabeater seals (Lobodon carcinophagus) in East Antarctica. The study was conducted in the Mertz Glacier Polynya region from July to August 1999. In total 89 crabeater seals were seen in 26 groups which ranged in size from 1 to 35 animals (mean = 3.2). The mean observed haulout density along a 200 m wide strip transect was 0.108 seals per km2, or 0.042 groups per km2. Crabeater seals were not uniformly distributed in the polynya but selected areas of stable ice over shallow (< 1000 m) waters. We used a generalized linear model to assess the relationship of seal distribution to the physical attributes of sea ice concentration, thickness, and ocean depth. We found that ice thickness and ocean depth were the most important determinants of seal distribution. Crabeater seals occurred in areas where the ice affords them a stable haulout platform while allowing them access to Antarctic krill that live directly beneath the ice.