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.

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.

In 1997 and 1998, we tagged and released 18013 red-legged banana prawns in the Joseph Bonaparte Gulf. The location of recaptures was documented for 916 tagged prawns in 1997 and 512 tagged prawns in 1998. Tag recapture information and commercial fishery logbook information was used to test whether red-legged banana prawns moved continuously to deeper waters or whether they moved first to deep water but then returned to shallower waters. The analysis is based on compartment models of recaptures per unit of fishing effort.

Buoys were released in the Southern Ocean (in Antarctic waters), in the Indian and Pacific Oceans, in the Tasman Sea and in The Great Australian Bight. 143 deployments were made between 1975 and 1995. The buoys were tracked by the NASA weather satellite NIMBUS-6, and later by the French System ARGOS aboard the satellite TRIOS-N. Buoy types include 4.5 m PVC/fiberglass spars (Cresswell et. al. CSIRO), 5m spars (Australian Bureau of Meteorology), and two variations of 2 m "torpedo" buoys (Cresswell, Richardson and Wood). Most of the buoys were drouged with 7.2m parachute at 20m depth. Sea surface temperature data was recorded and transmitted to satellite. Buoy drift speed and direction were calculated from successive satellite fixes.

This record is an overview entry for biological data collected on Diamantina cruise Dm 3/61. This cruise took place in the northeast Indian Ocean and the Timor Sea during 20 July to 26 August 1961, under the leadership of D. Tranter & J. MacIntyre. Biological data collected on this cruise include primary production rates; organisms with/without chlorophyll, total particles and occurrence of diatoms and dinoflagellates from phytoplankton stations; pigment samples; and zooplankton biomass. Data on seston, enrichment experiments and transparency recordings were also obtained. Please note: This metadata record is a preliminary entry derived from information in the cruise report. Individual data types - which may span several cruises - will be indexed separately within this metadata system in due course.

This record is an overview entry for biological data collected on Diamantina cruise Dm 2/61. This cruise took place in the Indian Ocean, Timor and Java Seas during 1 May to 12 June 1961, under the leadership of B. Newell. Biological data collected on this cruise include primary production rates; organisms with/without chlorophyll, total particles and occurrence of diatoms and dinoflagellates from phytoplankton stations; pigment samples; and zooplankton biomass. Please note: This metadata record is a preliminary entry derived from information in the cruise report. Individual data types - which may span several cruises - will be indexed separately within this metadata system in due course.