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Regional Seas | Arafura Sea
92 record(s)
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The dataset is a map of a benthic environmental classification of the North Marine Region (NMR). The aim of the classification was to summarise the way the physical environment near the seabed varies across the NMR. In particular, we were interested in variation within and across bioregion boundaries. The analysis was performed for the Department of the Environment and Water Resources for use in profiling of the NMR during the development of a marine bioregional plan for the region. The environmental classification process comprised laying a grid of cells over the NMR and sorting the cells into clusters on the basis of their physical environmental attributes. The classification method was unsupervised, model-based clustering with a Gaussian mixture model, and was performed with the MCLUST package for R. With this method, the statistical distributions of the clustering variables are modelled as a mixture of multivariate normal distributions. Clustering is a two-step process. First, the parameters of the mixture model are fitted by maximum likelihood. Second, the model is used to assign grid cells to clusters. The clustering variables were bathymetry, median current stress, sediment gravel percentage and average bottom salinity. The environmental characteristics of the nine clusters were (1) deep; (2) deep; (3) low stress, low gravel, low salinity; (4) average for the region; (5) average for the region; (6) shallow, low stress, high salinity; (7) shallow, low salinity; (8) shallow, high stress, gravel; and (9) shallow, high stress, high salinity.
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Northern Prawn Fishery fishers' GPS plotter data collected between 1977 and 1997. The data indicates which areas in the Gulf of Carpentaria are considered untrawlable.
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The dataset comprises GIS grids of fishing effort of the Northern Prawn Fishery (NPF) estimated from vessel monitoring system (VMS) data. The VMS is operated by the Australian Fisheries Management Authority (AFMA). It periodically records the location of each vessel in the fishery. Note that the activity of the vessel at the time is not recorded. The system's primary purpose is to monitor compliance with fishing regulations, but the data can also be used for research. To estimate fishing effort from the VMS records, we estimated the track of each fishing vessel by joining successive vessel locations with lines. We divided the track into apparent trawling and non-trawling sections (e.g. based on date, time and vessel speed), and calculated the time each trawling section spent in each cell of a GIS grid covering the managed area of the fishery. This method for estimating fishing effort from VMS data has limitations. Because a vessel may have taken a path other than a straight line between the polls, our straight line path (a) may only partially match the real path of the vessel, (b) may underestimate the length of the path traversed by the vessel, and (c) may underestimate the speed of the vessel. Note that (a) and (b) would affect which particular grid cells the trawling time was allocated to, but not the total trawling time that was added to the grid. The use of vessel speed to filter out non-trawling activity is imperfect because vessels may carry out other activities at speeds less than the maximum trawling speed.
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This record describes SVP data collected on 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. A total of 1 SVP casts were conducted over the duration of this voyage. Data are stored in ASCII format files with extention *.txt 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.
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This data set contains Simrad EK500 single beam echosounder data at 38 and 120 kHz and Simrad EA500 single beam echosounder data at 12 kHz from the Southern Surveyor. The EK500 data is primarily for water column characterisation (fish stocks, microplankton distribution) and on occasions for seabed classification (particularly prior to the EM300 swath mapper being installed), while the EA500 data is primarily for bathymetric readings.
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This data set contains Simrad EK500 single beam echosounder data at 38 and 120 kHz and Simrad EA500 single beam echosounder data at 12 kHz from the Southern Surveyor. The EK500 data is primarily for water column characterisation (fish stocks, microplankton distribution) and on occasions for seabed classification (particularly prior to the EM300 swath mapper being installed), while the EA500 data is primarily for bathymetric readings.
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This data set contains Simrad EK500 single beam echosounder data at 38 and 120 kHz and Simrad EA500 single beam echosounder data at 12 kHz from the Southern Surveyor. The EK500 data is primarily for water column characterisation (fish stocks, microplankton distribution) and on occasions for seabed classification (particularly prior to the EM300 swath mapper being installed), while the EA500 data is primarily for bathymetric readings.
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This record describes multibeam echosounder data collected on RV Investigator voyage IN2022_T01, titled "Transit: Cairns to Darwin 2022." The voyage took place between September 11, 2022 and September 17, 2022 (AEST), departing from Cairns and returning to Darwin. The Kongsberg EM710 MKII multibeam echosounder was used to acquire seafloor bathymetry and backscatter information and watercolumn backscatter between Cairns and Darwin. 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. During this voyage, the frequency range was set to 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 155 *.all files totaling 94.8 GB of raw bathymetry/backscatter data and 129 *.wcd files totaling 399 GB of watercolumn 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. GPS tide was computed using the EGM2008 model and applied to the processed data. Predicted tides were applied to the first 10 lines of the dataset due to lack of accurate GPS heighting available. Processed data has had outliers removed. Processed line data are available in *.gsf and ascii format, and processed bathymetry grids 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.
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This dataset comprises the current meter data collected from the Arafura Sea (2 sites) and Gulf of Carpentaria (1 site) during November 1987-February 1988. There are 3 moorings with 6 current meters represented in this dataset. Parameters typically recorded in current meter data comprise east-west and north-south velocity components, water temperature, pressure, and salinity at a nominal depth for each current meter. The data have been processed and are archived as part of the holdings of the CMR Data Centre in Hobart.
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Information about target species and by-catch, environment and practical prawn trawling was collected from current and past commercial operators in the Northern Prawn Fishery to guide and assist in the development of future CSIRO research projects in this geographic area. The information volunteered included both verbal and written responses to formal interviews, questionnaires and casual conversations. A casual approach seemed to encourage less guarded responses. Although the information refers to the defined management area of the NPF the practical experience to make such observations and interpretations may have been gained anywhere and where possible we have recorded the experience of the contributor in the fishing industry. The information volunteered was initially recorded onto data sheets and later in the laboratory transposed to Oracle tables.