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  • These aerial survey data of southern right whales (Eubalaena australis) off southern Australia were collected in August 2019. Such annual flights in winter/spring between Cape Leeuwin (Western Australia) and Ceduna (South Australia) have now been conducted over a 27-year period 1993-2019. These surveys have provided evidence of a population trend of around 6% per year, and a current (at 2014) population size of approximately 2300 of what has been regarded as the 'western' Australian right whale subpopulation. With estimated population size in the low thousands, it is presumed to be still well below carrying capacity. No trend information is available for the 'eastern' subpopulation of animals occurring around the remainder of the southern Australian Coast, to at least as far as Sydney, New South Wales and the populations size is relatively small, probably in the low hundreds. A lower than expected 'western' count in 2015 gives weak evidence that the growth rate may be starting to show signs of slowing, though an exponential increase remains the best description of the data. If the low 2015 count is anomalous, future counts may be expected to show an exponential increase, but if it is not, modelling growth as other than simple exponential may be useful to explore in future.

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    This dataset was generated to assess the biological impacts of ocean alkalinity enhancement (OAE) in the Southern Ocean. Deck-board incubation experiments were conducted at five sites spanning subantarctic to sea-ice regions during the RV Investigator MISO voyage (January–March 2024). Unfiltered surface seawater was incubated for 5–8 days following additions of three alkalinity sources: sodium hydroxide (NaOH), ground olivine, and steel slag, alongside untreated controls. Measurements collected at the beginning and end of each incubation included carbonate chemistry (total alkalinity and pH), macronutrients (nitrate, phosphate, silicate), chlorophyll-a, biogenic silica, photophysiology (Fv/Fm), and plankton community composition. Phytoplankton and bacterial abundances were quantified using flow cytometry, while genus-level phytoplankton composition was determined by light microscopy. A complementary dark leaching experiment quantified dissolved trace metal release from each OAE material using ICP-MS. The purpose of the study was to distinguish the biological effects of alkalinity change alone from those arising from collateral nutrient and trace-metal release, and to evaluate how different OAE materials influence phytoplankton growth and community structure in iron-limited Southern Ocean waters. The dataset supports assessment of ecological risks and co-benefits associated with ocean alkalinity enhancement as a carbon dioxide removal strategy.

  • Mesozooplankton community composition and structure were examined throughout the D’Entrecasteaux Channel, Huon Estuary and North West Bay, Tasmania, from November 2004 to October 2005, the data represented by this record was collected on the 11/02/2005. The composition of the mesozooplankton community was typical of inshore, temperate marine habitats, with seasonally higher abundance in summer and autumn and lower numbers in winter and spring. Copepods were the largest contributors to total abundance across all seasons and stations, while cladocerans and appendicularians were proportionally abundant in spring and summer. The faecal pellets of these three main groups, along with those of krill and amphipods, also contributed significantly to material recovered from sediment traps. Meroplanktonic larvae of benthic animals showed short-term peaks in abundance and were often absent from the water column for long periods. Spatially, North West Bay and the Channel had a higher representation of typically marine species, including Calanus australis and Labidocera cervi, while truly estuarine species, such as the copepod Gladioferens pectinatus, were more important in the Huon Estuary.

  • The goal of the program was developing comprehensive inventories and maps of the distribution and abundance of physical and biological seabed habitats, seagrasses and benthic assemblages to provide baseline environmental mapping and a description of ecological patterns. The benthic habitat mapping was performed by utilising R/Python and Maxent software within the species distribution modelling domain. We correlated the probability of occurrence of individual benthic habitat classes with the environmental predictors developed form the multibeam hydroacoustic dataset. The data is presented as a maximum likelihood map incorporating all five prediction classes: (1- Macroalgae; 2- Filter Feeders; 3- Seagrass; 4- Hard Corals; 5- Bare seafloor). An updated version of this data are available (2022) Revised predictive benthic habitat map for Darwin Harbour. Report prepared for Department of Environment, Parks and Water Security. Australian Institute of Marine Science, Darwin, 127 pp.

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    The ocean absorbs >90% of anthropogenic heat in the Earth system, moderating global atmospheric warming. However, it remains unclear how this heat uptake is distributed by basin and across water masses. Here we analyze historical and recent observations to show that ocean heat uptake has accelerated dramatically since the 1990s, nearly doubling during 2010–2020 relative to 1990–2000. Of the total ocean heat uptake over the Argo era 2005–2020, about 89% can be found in global mode and intermediate water layers, spanning both hemispheres and both subtropical and subpolar mode waters. Due to anthropogenic warming, there are significant changes in the volume of these water-mass layers as they warm and freshen. After factoring out volumetric changes, the combined warming of these layers accounts for ~76% of global ocean warming. We further decompose these water-mass layers into regional water masses over the subtropical Pacific and Atlantic Oceans and in the Southern Ocean. This shows that regional mode and intermediate waters are responsible for a disproportionate fraction of total heat uptake compared to their volume, with important implications for understanding ongoing ocean warming, sea-level rise, and climate impacts. The study titled “Recent acceleration in global ocean heat accumulation by mode and intermediate waters” was published in Nature Communications in October 2023. All datasets are publicly accessible (https://doi.org/10.5281/zenodo.17274477) and are additionally linked to this record.

  • This record describes the conductivity-temperature-depth (CTD) data and underway water sample data collected during the CSIRO Investigator transit voyage IN2024_T01, between 9 March and 20 March 2024. The objective of the voyage was for a safe transit from Fremantle, Western Australia, to Hobart, Tasmania. This record was part of a piggyback project whereby undergraduate students attained at-sea training through the Institute of Marine and Antarctic Studies and the University of Tasmania. The project aim was for students to gain experience with oceanographic data collection, processing and analysis. The CTD data includes 7 CTD profiles that measured conductivity, temperature, pressure, dissolved oxygen, salinity, fluorescence, turbidity and photosynthetically active radiation (PAR). Each of these parameters were collected during each CTD profile. The CTD data also includes calculated measurements of ammonium, nitrate, nitrite, phosphate, silicate, as well as chlorophyll-a, from select rosette bottles. The underway water sample data includes 41 duplicate samples of calculated measurements of chlorophyll-a and associated calculated measurements of ammonium, nitrate, nitrite, phosphate and silicate nutrient concentrations. In both data files, ODV quality flags have been used to indicate data quality.

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    The Fisheries Research and Development Corporation Project (FRDC) No. 2001/060 characterised and identified the distribution of the different benthic habitats of the Recherche Archipelago and identified the distribution of assemblages of fish, mobile invertebrates, filter feeding communities and seagrasses and the patterns and processes which structure them. Benthic habitat were determined from the interpretation of Landsat imagery, sidescan sonar imagery and video validation data collected within the Recherche region from May 2002 to November 2003.

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    The SeaMap Tasmania project undertook mapping of seafloor habitats across the nearshore Tasmanian coastline (0-40 m) - the first state to compile a statewide asssimilated benthic habitat dataset. This initiative comprised of collating aerial photography (from archives), acoustic mapping, and conducting underwater video surveys and field-based visual observations. From this, 1:25,0000 scale habitat maps were created for shallow coastal water to within 1.5 km of the coastline (or 40 m depth, which ever was arrived at first). This record provided access to the raw video and associated annotations from video transects, which were subsequently used as validation (ground-truthing) for habitat mapping. A submersible digital video camera was deployed at selected locations around the Tasmanian coastline. These samples were used to verify the aerial photography and echo sounder substrate classification and obtain more detailed information on biological assemblages. Transects were undertaken from the LWM (Low water mark) to 80 metres in depth or 1.5 kms from shore. Positional information was recorded for each video drop as a series of DGPS coordinates and also as a direct overlay of the DGPS output (position, date and time) onto the video.

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    Metric: Presence/absence of strong producer organisation that is accessible to fishery workers. Indicates whether workers and businesses have access to an effective industry representative organisation.

  • These aerial survey data of southern right whales (Eubalaena australis) off southern Australia were collected in August 2018. Such annual flights in winter/spring between Cape Leeuwin (Western Australia) and Ceduna (South Australia) have now been conducted over a 26-year period 1993-2018. These surveys have provided evidence of a population trend of around 6% per year, and a current (at 2014) population size of approximately 2300 of what has been regarded as the 'western' Australian right whale subpopulation. With estimated population size in the low thousands, it is presumed to be still well below carrying capacity. No trend information is available for the 'eastern' subpopulation of animals occurring around the remainder of the southern Australian Coast, to at least as far as Sydney, New South Wales and the populations size is relatively small, probably in the low hundreds. A lower than expected 'western' count in 2015 gives weak evidence that the growth rate may be starting to show signs of slowing, though an exponential increase remains the best description of the data. If the low 2015 count is anomalous, future counts may be expected to show an exponential increase, but if it is not, modelling growth as other than simple exponential may be useful to explore in future.