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.

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.

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.

Water column acoustic data collected in the Amundsen and Bellingshausen Seas (from 2008-02-26 to 2008-04-10) during cruise JR179. 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.

Water column acoustic data collected in the Scotia Sea (from 2008-01-01 to 2008-02-17) during cruise JR177. 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.

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.

Water column acoustic data collected in the Scotia Sea (from 2016-12-09 to 2017-01-15) during cruise JR16003. 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.

Water column acoustic data collected in the Scotia Sea (from 2015-11-13 to 2015-12-14) during cruise JR15002. 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.

Water column acoustic data collected in the Scotia Sea (from 2016-01-21 to 2016-02-21) during cruise JR15004. 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.