Energy requirements and daily food consumption of crabeater seals in the Antarctic winter pack-ice

• Other Authors: MCMAHON, CLIVE (hasPrincipalInvestigator), MCMAHON, CLIVE (processor), HINDELL, MARK A. (hasPrincipalInvestigator), HINDELL, MARK A. (processor), Australian Antarctic Data Centre (publisher)
• Format: Dataset
• Language: unknown
• Published: Australian Antarctic Data Centre
• Subjects: biota; oceans; ANIMALS/VERTEBRATES; EARTH SCIENCE; BIOLOGICAL CLASSIFICATION; MAMMALS; CONSUMPTION RATES; BIOSPHERE; ECOLOGICAL DYNAMICS; ECOSYSTEM FUNCTIONS; USE/FEEDING HABITATS; SPECIES/POPULATION INTERACTIONS; SEALS/SEA LIONS/WALRUSES; CARNIVORES; BATHYMETRY; CRABEATER SEALS; DENSITY; DISTRIBUTION; HABITAT USE; LOBODON CARCINOPHAGUS; MERTZ GLACIER POLYNYA; POLYNYA; SEA ICE; WINTER; FIELD INVESTIGATION; FIELD SURVEYS; OCEAN > SOUTHERN OCEAN; GEOGRAPHIC REGION > POLAR; Antarctic; East Antarctica; Mertz Glacier; Southern Ocean; The Antarctic; Antarc*; Antarctic Krill; Antarctica; Crabeater Seals; Lobodon carcinophagus; Sea ice; walrus*
• Online Access: https://researchdata.ands.org.au/energy-requirements-daily-pack-ice/699411; https://data.aad.gov.au/metadata/records/ASAC_1090; http://nla.gov.au/nla.party-617536

Although the most abundant of all mammalian predators in the Antarctic marine ecosystem, crabeater seals are also one of the least understood. The most fundamental question of all - how many are there? - is the focus of an extensive international collaborative program (the Antarctic Pack-ice Seal Program, or APIS). This study supplements APIS by providing additional data on the diving behaviour and food requirements of crabeater seals, that can be used in conjunction with census data to provide information on the role of crabeater seals in the antarctic ecosystem. Winter densities and distributions of Crabeater seals were collected during 1999. Crabeater seals were most often encountered on the shelf break. The data collected include numbers of seals sighted per hour in relation to the amount of time the ship spent in each 0.5 degree grid square. 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 200m wide strip transect was 0.108 seals per square kilometre, or 0.042 groups per square kilometre. Crabeater seals were not uniformly distributed in the polynya but selected areas of stable ice over shallow (less than 1000m) waters. We used a generalised 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.