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 gravity data collected on RV Investigator voyage IN2021_V03, titled "Integrated Marine Observing System: monitoring of East Australian Current property transports at 27 degrees South (multi-year)." The voyage took place from Hobart (TAS) to Brisbane (QLD) between May 8 and June 3, 2021. The gravity meter instrument is a MicroG Lacoste Air-Sea II. Data are stored in .ENV and .DAT data files at CSIRO. There are 62 files totalling 462 MB 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.

This record describes sub bottom profiler data collected on RV Investigator voyage IN2021_V03, titled "Integrated Marine Observing System: monitoring of East Australian Current property transports at 27 degrees South (multi-year)." The voyage took place from Hobart (TAS) to Brisbane (QLD) between May 8 and June 3, 2021. The Kongsberg SBP120 (sub bottom profiler) was used to acquire data containing the specular reflections at different sediment interfaces below the seafloor. The SBP120 provides a 3° by 3° angular resolution. The echosounder's frequency sweep range is from 2.5 to 7 kHz. The SBP120 was logged continuously for the extent of the voyage. Data are stored in *.raw (9,960 files 20.9 GB) raw and *.seg (9,956 files 20.8 GB) segy formats at CSIRO. The segy format data had a real time processing stream applied, which applies gain, a gain correction, matched filter with replica shaping, an attribute calculation for instantaneous amplitude and time variable gain. 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 XBT data collected on RV Investigator voyage IN2021_V03, titled "Integrated Marine Observing System: monitoring of East Australian Current property transports at 27 degrees South (multi-year)." The voyage took place from Hobart (TAS) to Brisbane (QLD) between May 8 and June 3, 2021. A total of 31 XBT casts were conducted over the duration of this voyage. 25 XBT casts were considered good and used for processing. Data are stored in netCDF files at CSIRO. 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 IN2021_v03, titled "Integrated Marine Observing System: monitoring of East Australian Current property transports at 27 degrees South (multi-year)." The voyage took place from Hobart (TAS) to Brisbane (QLD) between May 8 and June 3, 2021. The Kongsberg EM122 multibeam echosounder was used to acquire seafloor bathymetry, backscatter information and water column backscatter, during the transit and at the East Australian Current (EAC) Moorings site. 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 (459 files 26.4 GB) and backscatter and *.wcd format for watercolumn backscatter (423 files 28.9 GB) at CSIRO. Sound velocity profiles were applied to this data during data acquisition. Bathymetry data contained in *.all format are corrected for motion and position. The data has been reduced to approximate Mean Sea Level (MSL) using the Earth Gravitation Model 2008 (EGM2008) 1 arc-minute x 1 arc-minute grid spacing. Tide corrections were not applied to the processed data. Processed data had outliers removed. Processed line data are available in *.gsf (version 3.0.9) and ascii format, and processed bathymetry 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 IN2021_E01 (Trials and Calibration) which departed Hobart on the 10th November 2021 and returned to Hobart on the 14th November 2021. The purpose of this voyage was to undertake annual equipment calibrations and commissioning, sea trials and personnel training. The Simrad EK80 wide band transceivers (WBT) 18, 38, 70, 120, 200 and 333 kHz and the EK60 split-beam GPT 18, 70, 120, 200 and 333 kHz were calibrated at the start of this voyage at anchor in the Derwent Estuary on the 10th November 2021. The EK80 WBTs were calibrated using default settings for both CW and FM modes. The EK80 system was then used to acquire acoustic backscatter data to a range of 1500 m for the remainder of the voyage offshore to the southeast of Tasman Peninsula. All frequencies were logged sporadically for the extent of the voyage. The frequencies were set to passive for periods during the voyage when conducting other system calibrations. Data are stored in *.raw, *.bot and *.idx format at CSIRO. There are 289 files totalling 25.7 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 on RV Investigator voyage IN2021_E01 (Trials and Calibration) which departed Hobart on the 10th November 2021 and returned to Hobart on the 14th November 2021. 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. Data are stored in *.all raw format for bathymetry and backscatter and *.wcd format for watercolumn backscatter at CSIRO. There are 39 files totalling 1.31 GB of raw bathymetry (.all) data and 39 files totalling 1.82 GB of raw watercolum (.wcd) 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. GPS tide corrections were applied to the processed data using the EGM2008 model (EGM_2008_1Min_Aust_WGS84.csar). 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 IN2021_E01 (Trials and Calibration) which departed Hobart on the 10th November 2021 and returned to Hobart on the 14th November 2021. The purpose of this voyage was to undertake post port-period equipment calibrations and commissioning, sea trials and personnel training. The Kongsberg EM710 MKII multibeam echosounder was used to acquire seafloor bathymetry and backscatter information and watercolumn backscatter in Storm Bay and offshore to the southeast of Tasman Peninsula. A patch test calibration was performed to determine the angular offsets of the system. 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 and during this voyage was acquired with a frequency range setting of 70 to 100 kHz. Data are stored in *.all raw format for bathymetry and backscatter and *.wcd format for watercolumn backscatter at CSIRO. There are 78 files totalling 14.3 GB of raw bathymetry (.all) data and 76 files totalling 95.6 GB of raw watercolum (.wcd) 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. GPS tide corrections were applied to the processed data using the EGM2008 model (EGM_2008_1Min_Aust_WGS84.csar). Processed data has had outliers removed. Processed line data are available in *.gsf and ascii format, and processed bathymetry in geotiff format. 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 sub bottom profiler data collected on RV Investigator voyage IN2021_E01 (Trials and Calibration), which departed Hobart on the 10th November 2021 and returned to Hobart on the 14th November 2021. The Kongsberg SBP120 (sub bottom profiler) was used to acquire data containing the specular reflections at different sediment interfaces below the seafloor. The SBP120 provides a 3° by 3° angular resolution. The echosounder's frequency sweep range is from 2.5 to 7 kHz. The SBP120 was logged [continuously/sporadically] for the extent of the voyage. Data are stored in *.raw (596 files, 1.81GB) raw and *.seg (595 files, 1.8 GB) segy formats at CSIRO. The segy format data had a real time processing stream applied, which applies gain, a gain correction, bandpass filter (for depths < ~200m) or matched filter with replica shaping (for depths > ~200 m), and time variable gain. No attribute calculation for instantaneous amplitude was applied. 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 gravity data collected on RV Investigator voyage IN2021_E01 (Trials and Calibration) which departed Hobart on the 10th November 2021 and returned to Hobart on the 14th November 2021. The purpose of this voyage was to undertake post port-period equipment calibrations and commissioning, sea trials and personnel training. The gravity meter instrument is a MicroG Lacoste Air-Sea II. Data are stored in .ENV and .DAT data files at CSIRO. There are 7 files totalling 99MB of raw data in this dataset. A post voyage wharf tie was undertaken at the wharf in Hobart using a Scintrex Autograv CG-5 on 14th November 2021. Wharf tie data can be found in Hobart wharf_tie_2021_11_14.TXT, which is stored with the raw data. No processing has been conducted on this data. Additional information regarding this dataset is contained in the GSM data acquisition and processing report.