Acoustic backscatter data were collected on board the RRS Discovery during cruise DY158 on 05/01/2023 in Stromness Bay, South Georgia. Data were collected using a Simrad EK80 echosounder at 18, 38, 120, 200 and 333 kHz. Funding source: This work was carried out in the frame of WCB-POETS survey cruises, and the methane survey was funded by the Collaborative Antarctic Science Scheme (CASS).

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.

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.