This record describes scientific split-beam echosounder data collected on the RV Investigator voyage IN2021_V01, "Quantifying krill abundance for krill monitoring and management off the Australian Antarctic Territory", which departed Hobart on the 29th January 2021 and returned to Hobart on the 24th March 2021 (AEST). The Simrad EK80 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 near Mawson station, Antarctica. All frequencies were logged continuously for the extent of the voyage. Acquisition settings (pulse length, power) were varied for the transit and survey portions of the voyage according to science requirements. Specific settings for each time period can be obtained from the GSM voyage report. From 1 Feb, 2021 the 18kHz WBT was replaced with the 18kHz GPT which was run for the remainder of the voyage. A calibration was performed at the survey location on 13 Feb 2021. Data are stored in *.raw, *.bot and *.idx format at CSIRO. There are 3192 files totalling 295 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 multibeam echosounder data collected from the Marine National Facility (MNF) RV Investigator Voyage IN2020_V01, titled: “Development of William’s Ridge, Kerguelen Plateau: tectonics, hotspot magmatism, microcontinents, and Australia’s Extended Continental Shelf” between January 08 and March 06, 2020 departing from Henderson (WA) and returning back to Fremantle (WA). The Kongsberg EM122 multibeam echosounder was used to acquire seafloor bathymetry, backscatter information and watercolumn backscatter at Rig Seismic Seamount, Williams Ridge, Broken Ridge and on associated transits. 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 2164 files totalling 174 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. Tide corrections were not 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 IN2020_E01 (Trials and Calibration) which departed Hobart on the 29th July 2020 and returned to Hobart on the 6th August 2020. The purpose of this voyage was to undertake post port-period equipment calibrations and commissioning, sea trials and personnel training. The Kongsberg EM122 multibeam echosounder was used to acquire seafloor bathymetry, backscatter information and watercolumn backscatter in Storm Bay and offshore to the southeast of Tasman Peninsula. The EM122 provides a 1 degree by 1 degree angular resolution. The echosounder's nominal frequency is 12 kHz. A patch test calibration was performed to determine the angular offsets of the system on August 1st, 2020. Data are stored in *.all raw format for bathymetry and backscatter and *.wcd format for watercolumn backscatter at CSIRO. There are 98 files totalling 3.72 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. Tide corrections were not 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 IN2018_V08, The Balleny mantle plume: key role in Tasmania-Antarctic breakup?, which departed Hobart on the 27/12/2018 and returned to Hobart on the 10/01/2019. The voyage objectives was to identify/map seamounts of the Balleny seamount chain and dredge volcanic samples from the identified seamounts. The Kongsberg EM122 multibeam echosounder was used to acquire seafloor bathymetry, backscatter information and watercolumn backscatter in the Tasman Sea. 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 822 files totalling 42.7 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. Tide corrections were not 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 IN2019_E01, 'Post-Dry Dock Calibration Trials', which departed Singapore on the 19th July 2019 and returned to Cairns] on the 2nd August 2019. EK60 Calibration data was also collected on this voyage 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, within Australia's EEZ in the Arafura sea, the Torres Strait and the Coral Sea. All frequencies were logged continuously for the extent of the voyage within Australia's EEZ. Data are stored in *.raw, *.bot and *.idx format at CSIRO. There are 173 files totalling 15.9 GB of raw data in this dataset. Processing has been conducted on the calibration data only. 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 multibeam echosounder data collected on RV Investigator voyage IN2023_E01, 'Sea Trials and Calibrations' which departed Fremantle on the 07/01/2023 and returned to Fremantle on the 12/01/2023. The Kongsberg EM122 multibeam echosounder was used to acquire seafloor bathymetry, backscatter information and watercolumn backscatter at various times and depths throughout the voyage. 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 69 files totalling 3.91 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. Tide corrections [were/were not] 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 IN2018_E02, titled 'MNF Trials and Calibrations' which departed Hobart on the 3rd of September 2018 and returned to Hobart on the 9th of September 2018. The Kongsberg EM710 multibeam echosounder was used to acquire seafloor bathymetry and backscatter information around south eastern Tasmania. The EM710 provides a 0.5° by 1° transmit and receive angular resolution respectively. The echosounder's nominal frequency range is from 70 to 100 kHz. Data are stored in *.all raw format for bathymetry and backscatter at CSIRO. There are 97 files totalling 15.4 GB of raw data in this dataset. Multibeam bathymetry calibrations were performed on this trial. Tide corrections were not applied to the processed data. Processed data had outliers removed. Processed line data is not available as they were trials for calibration. Additional information regarding this dataset, including further 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 IN2017_C02, ['Hogan Group Hydrographic Survey – Bass Strait'] which departed Hobart on the 4th May 2017 and came alongside Bell Bay following completion of the survey on the 14th May 2017. The Simrad EK60 split beam echosounders [12], 18, 38, 70 120, 200 and 333 kHz were used to acquire acoustic backscatter data to a range of [range] m, around Bass Strait. All frequencies were logged sporadically for the extent of the voyage. The frequencies were set to passive for the periods of the voyage. Data are stored in *.raw, *.bot and *.idx format at CSIRO. There are 1,120 files totalling 22 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 IN2019_T02, titled: "Deep seascapes of the Great Barrier Reef: Uncovering submarine canyons and landslides." The voyage took place between October 4 and October 14, 2019 departing from Brisbane (QLD) and arriving in Darwin (NT). 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 Brisbane to Darwin transit. All frequencies were logged sporadically for the extent of the voyage. The frequencies were set to passive for the periods of the voyage. Data are stored in *.raw, *.bot and *.idx format at CSIRO. There are 728 files totalling 36 GB of raw data in this dataset. The EK60, EM122 and SBP120 were synchronised using K-Sync as often as possible to minimise cross-system interference. No p/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 from the Marine National Facility (MNF) RV Investigator Voyage IN2020_V08, titled "SOLACE - Southern Ocean Large Areal Carbon Export: quantifying carbon sequestration in subpolar and polar waters." The voyage took place between December 5, 2020 and January 16, 2021 departing from Hobart (TAS) and arriving in Hobart (TAS). The Simrad EK80 split beam echosounders 18, 38, 70 120, 200 and 333 kHz were used to acquire acoustic backscatter data to a range of 1500 m, at the three study locations and transit to and from Hobart . All frequencies were logged continuously for the extent of the voyage. Logging of "complex samples" occurred daily for one hour. Data are stored in *.raw (6273 files 625 GB) and *.idx (6273 files 63.0 MB) formats at CSIRO. 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.