Aerial surveys for pack-ice seals along the Ingrid Christensen and Princess Astrid Coasts, East Antarctica

Abstract

We conducted aerial surveys in the austral summer of 2009-2010 to count and record the spatial distribution patterns of pack-ice seals hauled-out along the Ingrid Christensen and Princess Astrid coast of East Antarctica. A total of 3,601 hauled-out seals were counted from six aerial surveys totalling a length of approx. 1,200km, with each survey lasting about two hours. Weddell Seal Leptonychotes weddellii was the most commonly sighted species in both the areas surveyed (98.2%), and had an encounter rate of 2.9 seals/km. The other species encountered during the survey were Crabeater Seal Lobodon carcinophaga (1.7%) and Leopard Seal Hydrurga leptonyx (0.03%). Group size of hauled-out Weddell Seals varied considerably and ranged from solitary to maximum of 42 individuals. The median group size of Weddell seals hauled-out along the Ingrid Christenson Coast was found to be significantly different between the December 2009 and January 2010 survey. Further, along this coast Weddell Seals were found hauled-out mainly close to the ice shelf and their spatial distribution appeared to be influenced by the extent of sea ice in the area.