Temperature data were collected from a tidepool at Rothera Point, Antarctica every two minutes from February 1999 to May 2000, with the aim of documenting tidal, diurnal and seasonal variability.

Marine debris washed up on beaches on Goudier Island has been recorded since 2014. Surveys are conducted on a monthly basis when the station is occupied during the summer season. This data contributes to the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) Marine Debris programme.

Acoustic backscatter data were collected on board the RRS Sir David Attenborough during polar science trials 2023 (cruise SD025) on 25/02/2023 in Admiralty Bay, King George Island, Antarctica. Data were collected using a Simrad EK80 echosounder at 18, 38, 70, 120, 200 and 333 kHz. The EK80 was calibrated on 10/03/2023 in the Weddell Sea. This work was supported by NERC core funding to BAS.

Acoustic backscatter data were collected on board the RRS James Clark Ross during cruise JR17002 on 20/01/2018 in Bransfield Strait and the caldera of Deception Island. Data were collected using a Simrad EK60 echosounder at 38, 70, 120 and 200 kHz. The EK60 was calibrated on 07/01/2018 in Stromness Harbour, South Georgia. More information about the calibration can be found in the Cruise Report for JR17002. This work was carried in the frame of the Polar Ocean Ecosystem TimeSeries - Western Core Box (POETS-WCB) project.

Acoustic backscatter data were collected on board the RRS James Clark Ross during cruise JR19001 on 10/12/2019 in Stromness Harbour and South Georgia. Data were collected using a Simrad EK60 echosounder at 38, 70, 120 and 200 kHz. The EK60 was calibrated on 09/12/2019 in Stromness Harbour, South Georgia. More information about the calibration can be found in the Cruise Report for JR19001. This work was carried in the frame of the Polar Ocean Ecosystem TimeSeries - Western Core Box (POETS-WCB) project.

This data set represents the model results plotted in the figures in Bett et al. (2024), produced using the MITgcm/WAVI ice/ocean coupled model. The model domain is the Amundsen Sea sector, where the simulations start in approximately the year 2015 and run for 180 years. Simulations are forced using idealised ocean boundary conditions which represent cold and warm conditions, along with a third extreme case where no ice shelf melting is applied. These simulations were produced in order to examine the ice/ocean processes that occur during future evolution of the region. For full descriptions of the results plotted in each figure see Bett et al. (2024). Funding was provided by NERC Grant NE/S010475/1, ITGC THWAITES MELT (NE/S006656/1), ITGC THWAITES PROPHET (NE/S006796/1) and the European Union''s Horizon 2020 grant PROTECT (869304).

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).

Raw (calibrated as per Demer et al., 2015) Simrad EK60 echosounder data (18, 38 and 120 kHz; Kongsberg Maritime, Norway) collected annually in August and September between 2011 and 2016 as part of the Barents Sea Ecosystem Survey (Eriksen et al., 2018) were obtained from the Norwegian Marine Data Centre (Institute of Marine Research, Norway). The data were used to evaluate the StrathE2EPolar (an end-to-end food web model incorporating ice-dependencies to simulate climate-fisheries interactions in the Barents Sea) model. Echosounder data were calibrated and processed (noise removed). Nautical-area-scattering coefficient (NASC, m2 nmi-2: average received echo energy over a given depth range scaled up to a square nautical mile) values were computed between 15 m (maximum vessel draft plus echosounder near-field for all surveys, vessels and frequencies) and 400 m (lower extent of StrathE2EPolar model domain). NASC values at 18 kHz were used as a proxy for fish biomass. NASC values at 120 kHz and where NASC 120 kHz > 38 kHz > 18 kHz were used as a proxy for macro-zooplankton biomass. NASC values were binned into a 0.5 by 0.5-degree grid and averaged to map the spatial distribution of fish and macro-zooplankton. Funded by NERC project Microbes to Megafauna Modelling of Arctic Seas (MiMeMo), NE/R012571/1 (lead), and NE/R012679/1.

These data are gonad index (gonad mass/total animal mass) and egg size measurements for two Antarctic marine invertebrates, the starfish Odontaster validus and the brittle star Ophionotus victoriae. Data are for samples hand-collected monthly, where weather permits, by scuba divers from sites near the British Antarctic Survey''s research station at Rothera Point, Adelaide Island. Samples were first collected in 1997 and have continued for 19 years to 2015.

Water column acoustic data collected in the Scotia Sea (from 2006-10-24 to 2006-12-03) during cruise JR161. Multi-frequency (38,120 and 200 kHz) acoustic data were collected using a Simrad EK60 echo sounder. The dataset comprises of calibrated and processed 38 kHz volume backscattering strength (Sv, dB re 1m-1). Data processing was undertaken using Echoview and Matlab. Processed netCDF data files are made available as part of the NERC Southern Ocean Network of Acoustics (SONA) and the EU MESOPP project.