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 IN2023_V06, titled: "Understanding Eddy Interactions and Their Impacts In the East Australian Current System." The voyage took place between October 9 and November 2, 2023, departing from Sydney (NSW) and returning to Sydney. The Simrad EK60 split beam echosounders for18kHz 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, around NSW/VIC coastal areas. All frequencies were logged continuously for the extent of the voyage. The 70kHz & 120kHz frequencies were set to passive for the periods of shallow mapping areas of the voyage. Data are stored in .raw, .bot and *.idx format at CSIRO. There are 394 files totalling 35.6 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_V09, titled "Valuing Australia’s new Gascoyne Marine Park." The voyage took place between 0000 November 19, 2022 and 0700 December 19, 2022 (UTC), departing from Fremantle and returning to Fremantle. The Simrad EK60 split beam echosounders for18kHz 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 [range] m, throughout the voyage including within the Gascoyne and Ningaloo Marine Parks. All frequencies were logged continuously for the extent of the voyage. The 38 & 70 were periodically set to passive for the during the voyage to optimise MBES seabed mapping data quality. Data are stored in .raw, .bot and *.idx format at CSIRO. There are 2344 files totalling 73 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 IN2024_V04, 'Linking East Australian Current dynamics and submarine canyon geomorphology to marine ecosystem hotspots' which departed Sydney on the Friday 7th June and returned to Brisbane on the Wednesday 3rd July. 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 Sydney and Brisbane, with primary mapping focused on Richmond and Solitary Canyons. If the bottom was deeper than 1500 m during the camera operations the logging range was extended to capture the full water column. All frequencies were logged sporadically for the extent of the voyage as to not interfere with the ADCP which took priority over the EK60/EK80 to fulfil the voyage objectives. Data are stored in .raw, .bot and *.idx format at CSIRO. There are 312 files totalling 28.4 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 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 the RV Investigator voyage IN2023_V03, SOTS: Southern Ocean Time Series automated moorings for climate and carbon cycle studies southwest of Tasmania which departed Hobart on May 12, 2023 and returned to Hobart on the May 25, 2023. 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 Hobart, the SOTS location and while on site. All frequencies were logged continuously for the extent of the voyage. There was a dedicated acoustic survey over the Patience Seamount while transiting to SOTS and also some opportunistic noise data collection to compare EK60 and EK80 noise levels. Data are stored in .raw, .bot and *.idx format at CSIRO. There are 1130 files totalling 53 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 Marine National Facility (MNF) RV Investigator voyage IN2024_V02, titled "SOTS: Southern Ocean Time Series automated moorings for climate and carbon cycle studies southwest of Tasmania." The voyage took place between March 31, 2024 and April 19, 2024 (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 1500 m from Hobart to the SOTS moorings sites and during the return transit. All frequencies were logged continuously for the extent of the voyage. Data are stored in .raw, .bot and *.idx format at CSIRO. There are 783 files totalling 73.7 GB of raw data in this dataset. Calibration values from the IN2023_E03 calibration were applied on acquisition. IMPORTANT NOTE: The 18 kHz transducer had a faulty channel for the duration of this voyage. Although data was logged, the 18 kHz data should NOT be used for quantitative analysis. 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 IN2025_V04, titled "Untangling the causes of change over 25 years in the southeast marine ecosystem - Voyage IV." The voyage took place between May 27, 2025 and June 28, 2025 (AEST), departing from Hobart and returning to Hobart. The Simrad EK80 split beam echosounders for 18, 38, 70 120, and 200 kHz were used to acquire acoustic backscatter data to a range of up to1500 m, between Hobart and Eden. Logging range was changed throughout the voyage based on depth. The 18, 38, 70 120, and 200 kHz frequencies were logged continuously for the extent of the voyage. The 333 kHz was set to passive for the duration of the voyage due to a known issue with the transducer. Data are stored in .raw, .bot and *.idx format at CSIRO. There are 1,164 files totalling 112 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 high-precision wide-band echosounder data collected on the RV Investigator voyage IN2020_V06, titled "Probing the Australian-Pacific Plate Boundary: Macquarie Ridge in 3-D." The voyage took place between October 8 and November 3, 2020 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 1,500 m, around Macquarie Island and from Hobart transit. All frequencies were logged for the extent of the voyage, except where required to turn off for operational requirements. The frequencies were set to active for the whole period of the voyage. Data are stored in .raw, .bot and *.idx format at CSIRO. There are 818 files totalling 78.1 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.