These datasets and accompanying syntheses provide a greater understanding of fundamental ecosystem processes in the Southern Ocean, support modelling of predator distributions under future climate scenarios and create inputs that can be incorporated into decision making processes by management authorities. In this data paper, we present the compiled tracking data from research groups that have worked in the Antarctic since the 1990s. The data are publicly available through biodiversity.aq and the Ocean Biogeographic Information System. The archive includes tracking data from over 70 contributors across 12 national Antarctic programs, and includes data from 17 predator species, 4060 individual animals, and over 2.9 million observed locations.Scientific Data | (2020) 7:94 | https://doi.org/10.1038/s41597-020-0406-x www.nature.com/scientificdata www.nature.com/scientificdata/ circum-Antarctic synthesis yet exists that crosses species boundaries. This deficiency prompted the Expert Group on Birds and Marine Mammals (EG-BAMM) and the Expert Group on Antarctic Biodiversity Informatics (EGABI) of the Scientific Committee on Antarctic Research (SCAR; www.scar.org) to initiate in 2010 the Retrospective Analysis of Antarctic Tracking Data (RAATD). RAATD aims to advance our understanding of fundamental and applied questions in a data-driven way, matching research priorities already identified by the SCAR Horizon Scan 9,21 and key questions in animal movement ecology 22 . For these reasons, we worked on the collation, validation and preparation of tracking data collected south of 45 °S. Data from over seventy contributors (Data Contacts and Citations 23 ) were collated. This database includes information from seventeen predator species, 4,060 individuals and over 2.9 million at-sea locations. To exploit this unique dataset, RAATD is undertaking a multi-species assessment of habitat use for higher predators in the Southern Ocean 24 .RAATD will provide a greater understanding of predator distributions under varying climate regimes, and provide outputs that can inform spatial management and planning decisions by management authorities such as the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR; www.ccamlr.org). Our synopsis and analysis of multi-predator tracking data will also highlight regional or seasonal data-gaps.Scientific Data | (2020) 7:94 | https://doi.

We examined how seabirds might be used to study marine environmental variables, which necessitates knowing location and the value of the variable to be studied. Five systems can potentially be used for determination of location: VHF (Very High Frequency) telemetry, PTT (Platform Terminal Transmitters) telemetry, GLS (Global Location Service) geolocation methods, dead reckoning and GPS (Global Positioning System), each with its own advantages with respect to accuracy, potential number of fixes and size. Temperature and light were used to illustrate potential difficulties in recording environmental variables. Systems currently used on seabirds for measurement of temperature respond slowly to environmental changes; thus, they may not measure sea surface temperature adequately when contact periods with water bodies are too short. Light can be easily measured for light extinction studies, but sensor orientation plays a large role in determining recorded values. Both problems can be corrected. The foraging behaviour of seabirds was also examined in order to identify those features which would be useful for determination of marine environmental variables at a variety of spatial and temporal scales. Area coverage by birds is highly dependent on breeding phase and tends to be concentrated in areas where prey acquisition is particularly enhanced. The identification of these sites may be of particular interest to marine biologists. 'Plungers' and 'divers' are potentially most useful for assessment of variables deeper within the water column, with some divers spending up to 90% of their time sub-surface. Few seabirds exploit the water column deeper than 20 m, although some divers regularly exceed 50 m (primarily penguins and auks), while 2 species dive in excess of 300 m. The wide-ranging behaviour of seabirds coupled, in many instances, with their substantial body size makes them potentially excellent carriers of sophisticated environmental measuring technology; however, the ethical question of how much the well-being of birds can, and should, be compromised by such an approach needs to be carefully considered.

ObjectiveSatellite telemetry was used to investigate the migratory behaviour of southern elephant seals (Mirounga leonina). The seal studies were part of the German-Argentinean cooperation project and carried out at Stranger Point on King George Island between September 1996 and February 1997. Stranger Point (62°14'S; 58°40'W) is the southernmost breeding site of elephant seals. Elephant seals are able to dive to depths in excess of 1500 m and feed on squid and fish. The objective of this study was to identify the wintering areas and feeding grounds of elephant seals of this true Antarctic breeding colony. The results can potentially be compared between years or sites, in order to monitor differences in migratory and foraging behaviour that can be attributed to environmental changes in physical parameters (e.g. sea ice distribution) or to human impact on prey resources of these top predators. Field methodsAdult female elephant seal with satellitelinked dive recorder (SDR). SDRs were glued to the hair on the backs of 7 two month-old juveniles and on the heads of 13 moulted cows. To attach the instruments, seals were sedated with a combination of ketamine, xylazin, and diazepam. The initial doses of the drugs were either administered by hand (juveniles) or by a dart gun (adults) with automatically evacuating syringes. To maintain an immobilization of 1.5 to 3 h, small additional doses of ketamine and/or diazepam were administered by hand while the transmitters were being attached and the epoxy resin allowed to set.Satellite-linked dive recorder. Two types of ARGOS (CLS/Service Argos, Toulouse, France) transmitters were used in this study: 1) Satellite transmitters (ST-10 Telonics, Mesa, AZ, USA) are designed to provide the seals' at-sea locations. 2) In addition to transmissions of locations, satellite-linked dive recorders (SDR T-6 Wildlife Computers, Redmond, WA, USA) also process data on dive depths in the form of histograms. The histograms are encoded into messages and transmitted to a polar-orbiting satellite. The accessed data provide the horizontal extent of the seals' migrations and the distribution of their dive depths. Results and DiscussionComputer animation: To obtain a comprehensive picture of the seal's foraging activity in its three-dimensional marine environment the data need to be interpreted in the context of both biological and physical parameters. In our first attempt, a computer animation was developed to relate the animals behaviour to sea ice cover. A QuickTime (Apple Computer, Inc.) animation shows the tracks of the satellite tagged elephant seals in conjunction with seasonal changes in sea ice cover in the Antarctic Peninsula region from

In aquatic-mating pinnipeds, acoustic communication plays an important role in male competition and mate attraction. Vocal repertoire size and composition during the breeding season varies between species and is presumed to be a product of interspecific differences in sexual selection. In this study, we examine seasonal and diel patterns in acoustic repertoire size, composition and call activity of 4 Antarctic pinniped species: Weddell seal Leptonychotes weddellii, leopard seal Hydrurga leptonyx, Ross seal Ommatophoca rossii and crabeater seal Lobodon carcinophaga. An

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