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.

We assembled tracking data from seabirds (n = 12 species) and marine mammals (n = 5 species), collected between 1991 and 2016, from across the Antarctic predator research community. See https://data.aad.gov.au/metadata/records/SCAR_EGBAMM_RAATD_2018_Standardised and https://data.aad.gov.au/metadata/records/SCAR_EGBAMM_RAATD_2018_Filtered for the tracking data. Habitat selectivity modelling was applied to these tracking data in order to identify the environmental characteristics important to each species, and to produce circum-Antarctic predictions of important geographic space for each individual species. The individual species maps were then combined to identify regions important to our full suite of species. This approach enabled us to account for incomplete tracking coverage (i.e., colonies from which no animals have been tracked) and to produce an integrated and spatially explicit assessment of areas of ecological importance across the Southern Ocean. The data attached to this metadata record include the single-species maps for Adelie, emperor, king, macaroni, and royal penguins; Antarctic and white-chinned petrels; black-browed, grey-headed, light-mantled, sooty, and wandering albatross; humpback whales; Antarctic fur seal, southern elephant seals, and crabeater and Weddell seals. The data also include the integrated maps that incorporate all species (weighted by colony size, and unweighted). See the paper and its supplementary information for full details on the modelling process and discussion of the model outputs.

The Retrospective Analysis of Antarctic Tracking Data (RAATD) is a Scientific Committee for Antarctic Research (SCAR) project led jointly by the Expert Groups on Birds and Marine Mammals and Antarctic Biodiversity Informatics, and endorsed by the Commission for the Conservation of Antarctic Marine Living Resources. The RAATD project team consolidated tracking data for multiple species of Antarctic meso- and top-predators to identify Areas of Ecological Significance. These datasets constitute the compiled tracking data from a large number of research groups that have worked in the Antarctic since the 1990s. This metadata record pertains to the "standardized" version of the data files. These files contain position estimates as provided by the original data collectors (generally, raw Argos or GPS locations, or estimated GLS locations). Original data files have been converted to a common format and quality-checking applied, but have not been further filtered or interpolated. Periods at the start or end of deployments were identified and discarded if there was evidence that location data during these periods did not represent the animals' at-sea movement. For example, tags may have been turned on early (thereby recording locations prior to their deployment on animals) or animals may have remained at the deployment site, e.g. the breeding colony, for an extended period at the start or end of the tag deployment. Some tracks also showed a marked deterioration in the frequency and quality (for PTTs) of location estimates near the end of a track. Such locations were visually identified based on maps of each track in conjunction with plots of location distance from deployment site against time. This information is captured in the location_to_keep column appended to each species’ data file (1 = keep, 0 = discard). The code used to trim the tracks can be found in the https://github.com/SCAR/RAATD repository. This data set comprises one metadata csv file that describes all deployments, along with data csv files (17 files, one per species) containing the position data. For details of the file formats, consult the data paper. The data are also available in a filtered version (see https://data.aad.gov.au/metadata/records/SCAR_EGBAMM_RAATD_2018) that have been processed using a state-space model in order to estimate locations at regular time intervals.

The Retrospective Analysis of Antarctic Tracking Data (RAATD) is a Scientific Committee for Antarctic Research (SCAR) project led jointly by the Expert Groups on Birds and Marine Mammals and Antarctic Biodiversity Informatics, and endorsed by the Commission for the Conservation of Antarctic Marine Living Resources. The RAATD project team consolidated tracking data for multiple species of Antarctic meso- and top-predators to identify Areas of Ecological Significance. These datasets constitute the compiled tracking data from a large number of research groups that have worked in the Antarctic since the 1990s. This metadata record pertains to the "filtered" version of the data files. These files contain position estimates that have been processed using a state-space model in order to estimate locations at regular time intervals. For technical details of the filtering process, consult the data paper. The filtering code can be found in the https://github.com/SCAR/RAATD repository. This data set comprises one metadata csv file that describes all deployments, along with data files (3 files for each of 17 species). For each species there is: - an RDS file that contains the fitted filter model object and model predictions (this file is RDS format that can be read by the R statistical software package) - a PDF file that shows the quality control results for each individual model - a CSV file containing the interpolated position estimates For details of the file contents and formats, consult the data paper. The data are also available in a standardized version (see https://data.aad.gov.au/metadata/records/SCAR_EGBAMM_RAATD_2018_Standardised) that contain position estimates as provided by the original data collectors (generally, raw Argos or GPS locations, or estimated GLS locations) without state-space filtering.