This record describes multibeam echosounder data collected on RV Investigator voyage IN2023_V01, titled "Antarctic Bottom Water Production in the past: Records from marine sediments, Cape Darnley, East Antarctica". The voyage took place between 25th January, 2023 and 2nd March, 2023 departing from Henderson's (WA) and arriving in Hobart (TAS). The Kongsberg EM710 MKII multibeam echosounder was used to acquire seafloor bathymetry and backscatter information and watercolumn backscatter between Fremantle to Antarctica and Albany to Hobart. The EM710 MKII provides a 0.5° by 1° transmit and receive angular resolution respectively. The echosounder's nominal frequency range is from 40 to 100 kHz. Data are stored in .all raw format for bathymetry and backscatter and .wcd format for watercolumn backscatter at CSIRO. There are 102 files totalling 26.3 GB of raw data in this dataset. Sound velocity profiles were applied to this data during data acquisition. Bathymetry data contained in *.all format are corrected for motion and position. Bathymetry data contained in .all format are corrected for motion and position. GPS tide was computed using the EGM2008 model and applied to the processed data. Processed data had outliers removed. Processed line data are available in .gsf and ascii format, and processed bathymetry and backscatter grids in geotiff format. Additional information regarding this dataset, including information on processing streams, is contained in the GSM data acquisition and processing report. Additional data products may be available on request.

This record describes multibeam echosounder data collected on RV Investigator voyage IN2023_V01, titled "Antarctic Bottom Water Production in the past: Records from marine sediments, Cape Darnley, East Antarctica". The voyage took place between 25th January, 2023 and 2nd March, 2023 departing from Henderson's (WA) and arriving in Hobart (TAS). The Kongsberg EM122 multibeam echosounder was used to acquire seafloor bathymetry, backscatter information and watercolumn backscatter between Fremantle to Antarctica and Albany to Hobart. The EM122 provides a 1 degree by 1 degree angular resolution. The echosounder's nominal frequency is 12 kHz. Data are stored in .all raw format for bathymetry and backscatter and .wcd format for watercolumn backscatter at CSIRO. There are 1,395 files totalling 60 GB of raw data in this dataset. Sound velocity profiles were applied to this data during data acquisition. Bathymetry data contained in *.all format are corrected for motion and position. Bathymetry data contained in .all format are corrected for motion and position. GPS tide was computed using the EGM2008 model and applied to the processed data. Processed data had outliers removed. Processed line data are available in .gsf and ascii format, and processed bathymetry and backscatter grids in geotiff format. Additional information regarding this dataset, including information on processing streams, is contained in the GSM data acquisition and processing report. Additional data products may be available on request.

This record describes scientific split-beam echosounder data collected on the RV Investigator voyage IN2016_E01, 'East Tasman Plateau – key to unravelling the onset of the Antarctic Circumpolar Current/MNF Equipment Sea Trials,' which departed Hobart on the 17 August 2016 and returned to Hobart on the 22 August 2016. The Simrad EK60 split beam echosounders 18, 38, 70, 120, 200 and 333 kHz were used to acquire acoustic backscatter data to a maximum range of 1500 m between Hobart and the Cascade Seamount. All frequencies were logged continuously for the extent of the voyage. Data are stored in .raw, .bot and *.idx format at CSIRO. There are 109 files totalling 9.46GB of raw data in this dataset. No processing has been conducted on this data. A calibration was performed during this voyage on August 17. Additional information regarding this dataset is contained in the GSM data acquisition and processing report. Additional data products may be available on request.

This record describes scientific split-beam echosounder data collected on the RV Investigator voyage IN2021_V02 (SOTS: Southern Ocean Time Series automated moorings for climate and carbon cycle studies southwest of Tasmania), which departed Hobart on the 14th April 2021 and returned to Hobart on the 28th April 2021. The Simrad EK80 wide band transceivers (WBT) 38, 70, 120, 200 and 333 kHz, as well as the EK60 split-beam GPT 18kHz were used to acquire acoustic backscatter data to a range of 1500 m, during the voyage. All frequencies were logged sporadically (only when transiting) for the extent of the voyage. The frequencies were set to passive for the periods when stationary during the voyage. Data are stored in .raw, .bot and *.idx format at CSIRO. There are 422 files totalling 40.6 GB of raw data in this dataset. No processing has been conducted on this data. Additional information regarding this dataset is contained in the GSM data acquisition and processing report. Additional data products may be available on request.

This record describes scientific split-beam echosounder data collected on the RV Investigator voyage IN2017_V01, 'Interactions of the Totten Glacier with the Southern Ocean through multiple cycles. ‘Sabrina Seafloor Survey' which departed Hobart on the 14th January 2017 and returned to Hobart on the 5th March 2017. The Simrad EK60 split beam echosounders 18, 38, 70 120, 200 and 333 kHz were used to acquire acoustic backscatter data to a range of 1500 m, between Hobart and Totten Glacier. All frequencies were logged continuously for the extent of the voyage. Data are stored in .raw, .bot and *.idx format at CSIRO. There are 1120 files totalling 31.5 GB of raw data in this dataset. No processing has been conducted on this data. Additional information regarding this dataset is contained in the GSM data acquisition and processing report. Additional data products may be available on request.

This record describes scientific split-beam echosounder data collected on the RV Investigator voyage IN2023_V05, titled "Untangling the causes of change over 25 years in the southeast marine ecosystem (SEA-MES Voyage 1). The voyage took place between June 28, 2023 and July 30, 2023 (AEST), departing from Hobart and returning to Hobart. The Simrad EK60 split beam echosounders for 18kHz and Simrad EK80 split beam echosounders for 38, 70 120, 200 and 333 kHz were used to acquire acoustic backscatter data to a range of 1500m, between Hobart and Sydney. All frequencies were logged continuously for the extent of the voyage. The 70 & 120 kHz frequencies were set to passive for periods of the voyage. Data are stored in .raw, .bot and *.idx format at CSIRO. There are 809 files totalling 68.4 GB of raw data in this dataset. No Processing has been conducted on this data. Additional information regarding this dataset is contained in the GSM data acquisition and processing report. Additional data products may be available on request.

This record describes scientific split-beam echosounder data collected on the RV Investigator voyage IN2016_V03, 'Monitoring Ocean Change and Variability along 170° W from the ice edge to the equator', which departed Hobart on the 26 April 2016 and returned to Lautoka, Fiji on the 30 June 2016. There was a port call at Wellington, New Zealand, 26 - 27 May for some science personnel change; this resulted in two "legs" of the voyage therefore Leg 1 is 26 April - 26 May 2016, and Leg 2 27 May - 30 June 2016. During Leg 1 the EK60 was predominately set to passive on all frequencies except for the 18 kHz which was run to full ocean depth as redundancy to the EM122 depth for CTD casts. The EK60 was also turned on with each individual frequency during transit to thoroughly test the interaction between the individual frequencies of EK60 and each of the ADCP’s. The EK60 was not run at all on Leg 2 as it was thought that it could cause interference with the ADCP data. Data are stored in .raw, .bot and *.idx format at CSIRO. There are 1494 files totalling 63.1 GB of raw data in this dataset. No processing has been conducted on this data. Additional information regarding this dataset is contained in the GSM data acquisition and processing report. Additional data products may be available on request.

This record describes scientific split-beam echosounder data collected on the RV Investigator voyage IN2024_V03, titled "Untangling the causes of change over 25 years in the southeast marine ecosystem (SEA-MES Voyage 2)." The voyage took place between May 01, 2024 and May 31, 2024 (AEST), departing from Hobart and returning to Sydney. The Simrad EK60 split beam echosounders for 18kHz and Simrad EK80 split beam echosounders for 38, 70 120, 200 and 333 kHz were used to acquire acoustic backscatter data to a range of 1500 m, between the shelf areas of eastern Australia from Hobart, TAS to Sydney, NSW. All frequencies were logged continuously for the extent of the voyage. The frequencies 70kHz & 120kHz were set to passive for small periods of mapping during the voyage. Data are stored in .raw, .bot and *.idx format at CSIRO. There are 688 files totalling 64.3 GB of raw data in this dataset. No post processing has been conducted on this data. Additional information regarding this dataset is contained in the GSM data acquisition and processing report. Additional data products may be available on request.

This record describes scientific split-beam echosounder data collected on the RV Investigator voyage IN2022_V03, "SOTS: Southern Ocean Time Series automated moorings for climate and carbon cycle studies southwest of Tasmania", which departed Hobart on the 4th May 2022 and returned to Hobart on the 15th May 2022 (AEST). The Simrad EK60 split beam GPT for 18kHz and Simrad EK80 split beam WBTs for 38, 70 120, 200 and 333 kHz were used to acquire acoustic backscatter data to a range of 1500 m during transits. All frequencies were logged continuously for the extent of the voyage, except for periods of mooring recovery/deployment when all acoustic systems were mandated to be suspended to communicate with the mooring beacons. Data are stored in .raw, .bot and *.idx format at CSIRO. There are 436 files totalling 41.5 GB of raw data in this dataset. Additional information regarding this dataset is contained in the GSM data acquisition and processing report. Additional data products may be available on request.

This record describes scientific split-beam echosounder data collected on RV Investigator research charter, IN2015_C01, 'GAB deep water geological and benthic ecology program' which departed Hobart on the 25 October and returned to Port Lincoln on the 28 November. A short sea trial voyage (October 22 - 25, Hobart - Hobart) was undertaken prior to the charter. Data for those days is also included in this data set. The Simrad EK60 split beam echosounders 18, 38, 70 120, 200 and 333 kHz were used to acquire acoustic backscatter data during the voyage. Data are stored in .raw, .bot and *.idx format at CSIRO. There are 6795 files totalling 102 GB of raw data in this dataset. No processing has been conducted on this data. Additional information regarding this dataset is contained in the GSM data acquisition and processing report. Additional data products may be available on request.