Microscopy data on the percentages of liverwort stem length colonised by (i) stained hyphal coils, (ii) stained septate hyphae and (iii) dark septate hyphae, and (iv) percentages of rhizoids colonised by hyphae, in 16 leafy liverwort species sampled from sub-Antarctic South Georgia. Specimens were collected in 2011 and 2016 from 12 sites on the Thatcher Peninsula, South Georgia. The specimens have been deposited in the British Antarctic Survey herbarium. This project was funded by NERC under the British Antarctic Survey Long Term Monitoring programme.

The weights of fledging Gentoo penguin chicks at Maiviken have been monitored since 2010. The colony at Maiviken, can have over 1000 breeding pairs. Each year, just before their departure from the colony, a sample of 50 fledgling birds are weighed as part of a long-term monitoring programme. These data are submitted to the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) as part of their Ecosystem Monitoring Programme (CEMP). This work was funded by Natural Environment Research Council (UK) core funding to the British Antarctic Survey.

During several austral summers covering a 13 year period, we collected a random sample of body feathers from chicks of 11 sympatric species of Procellariiform (wandering albatross Diomedea exulans -79 individuals in total-, black-browed albatross Thalassarche melanophris - 51-, grey-headed albatross T. chrysostoma - 58 -, light-mantled sooty albatross Phoebetria palpebrata - 34 -, northern giant petrel Macronectes halli - 59 -, southern giant petrel M. giganteus - 60 -, white-chinned petrel Procellaria aequinoctialis - 39 -, blue petrel Halobaena caerulea - 19 - , Antarctic prion Pachyptila desolata - 19 -, South Georgian diving petrel Pelecanoides georgicus - 2 - and common diving petrel P. urinatrix - 6 -) to analyse Delta15N and Delta13C.

The data include size, sex, location and morphological measurements and of Muraenolepis specimens included in Fitzcharles et al. (2021). The morphometric data were primarily collected from fish captured during South Georgia Groundfish Surveys in 2003, 2004 and 2005, with additional data obtained from type specimens and extracted from published descriptions of Muraenolepididae. For genetic studies, tissue samples from the South Georgia specimens were supplemented by additional tissue samples from Muraenolepis in other parts of the Southern Ocean. Source, location and depth of capture are included for all specimens that were sequenced, together with sequence Accession Numbers (to the DNA Database of Japan) for Cox 1 and 16S rRNA sequences. The work was primarily funded by the Government of South Georgia & the South Sandwich Islands and was a component part of Elaine Fitzcharles'' PhD (University of St Andrews).

We present a new bathymetric compilation of the greater South Georgia region, here defined by a bounding box of ~900km (45W to 19W) by ~580km (63S to 50S) and covering an area of 530,000 km2. The region includes the South Georgia shelf, the Shag Rock shelf (to the west of South Georgia), the surrounding continental slopes and adjacent deep sea. This bathymetry grid was compiled from a variety of different data sources including multibeam swath bathymetry collected from scientific cruises undertaken by British Antarctic Survey (BAS), Alfred Wegener Institute (AWI) and the Institute of Geophysics, University of Texas. The grid has been constructed using a layered hierarchy dependent on accuracy of each dataset. The data is available as a 100m resolution GeoTIFF, ESRI ascii grid or KMZ file of elevation data along with a shapefile indicating the spatial coverage of all the contributing datasets. This work was supported by the National Environmental Research Council (grant number NE/L002531/1). For further information regarding the creation of this dataset please refer to doi:10.1038/srep33163.

Cetacean sightings in South Georgia and South Sandwich Islands waters, made by a team of four professional marine mammal observers during the British Antarctic Survey CCAMLR synoptic krill survey on the RRS Discovery (DY098), January and February 2019. The latitude and longitude of each sighting, the identified species, bearing and distance from the vessel, and estimated group size are provided. These data have been used by BAS to estimate (i) humpback whale and (ii) baleen whale abundance in South Georgia and South Sandwich Islands waters in 2019. Funding was provided by the Foreign, Commonwealth and Development Office, as part of the Overseas Territories Blue Belt programme, as well as the South Georgia Heritage Trust, Friends of South Georgia Island and Darwin PLUS award DPLUS057.

Platform Transmitting Terminal (PTT) tags were used to track Gentoo penguins from Maiviken and Ocean Harbour, South Georgia, from June to September 2018. PTT tags were attached to the lower back feathers with tape and glue. PTT tags use the ARGOS satellite system to collect geospatial data. Tags were deployed to provide information on the protection afforded to Gentoo penguins by the 12NM no take zone (part of the South Georgia and South Sandwich Island MPA that is closed to fishing), and the krill fishing grounds.

This dataset contains processed acoustic backscatter data that reflect integrated density estimates for Antarctic krill (Euphausia superba). The acoustic backscatter data are from the Western Core Box (WCB), comprising 8 acoustic transects that span the shelf-break at South Georgia. The data were obtained from a time series of 22 cruises carried out between 1996/97 and 2019/20. Data were collected using either a Simrad EK500 or EK60 echo sounder by biological oceanographers working at the British Antarctic Survey under the Ecosystems scientific research programme and predecessor Discovery 2010 and Dynamo research programmes. Funding was provided by the NERC/BAS Antarctic, Logistic, Infrastructure (ALI) Science and predecessor Long Term Monitoring Science research programmes.

This dataset contains reflectance spectra measurements of Antarctic krill (Euphausia superba) that were sampled from the Scotia Sea in the Southern Ocean. Reflectance measurements were made on board on freshly caught krill, using a spectroradiometer. A number of these reflectance experiments were carried out across different regions of the Scotia Sea, on male, female and juvenile krill. Reflectance measurements are given for krill in both in situ and filtered seawater, as well as for water without krill. Data are presented in terms of remote sensing reflectance (Rrs). Funding for the work was primarily through a bursary awarded to Anna Belcher from Antarctic Science Ltd. Additionally, funding from the BAS ecosystems programme supported the project. The Natural Environment Research Council Field Spectroscopy Facility (NERC FSF) loaned the equipment required to carry out this research.

This dataset contains the mean position of the Southern Antarctic Circumpolar Current front (SACCF) in the Scotia Sea, southwest Atlantic sector of the Southern Ocean. The location of the front was determined from analysis of the geopotential anomaly field calculated from quality-controlled potential temperature and salinity data from the World Ocean Database 1998 (Levitus et al., 1998) supplemented by an additional hydrographic profile obtained from the Scripps Institute of Oceanography, as detailed by Thorpe (2001) and Thorpe et al. (2002). The geopotential anomaly data were gridded at a horizontal resolution of one quarter degree and spanned the period 1911-1990. The front position was generated as part of a studentship awarded to SE Thorpe, funded by the Natural Environment Research Council with CASE support from the British Antarctic Survey. The studentship was supervised by KJ Heywood, MA Brandon and DP Stevens.