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This database contains sampling effort, catch records, biological data, and water quality data for sampling and catches of elasmobranchs in northern Australian rivers, estuaries and coasts undertaken under the National Environmental Research Program (NERP) Marine Biodiversity Hub Project 2.4 'Supporting Management of Listed and Rare Species'. and the National Environmental Science Program (NESP) Marine Biodiversity Hub Project A1 'Northern Australian Hotspots for the Recovery of Threatened Euryhaline Elasmobranchs'. Surveys using gillnets and rod-and-line were undertaken in the Top End region of the Northern Territory and the Kimberley region of Western Australia. Selected animals were tagged for movement ecology, habitat use and mortality estimates (acoustic telemetry), and tissue samples were collected from all fish for molecular analyses (population genetics and close-kin mark-recapture).
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We evaluate the status of shellfish reef ecosystems in Australia including their historical distribution and loss, regulation and management and identify current research priorities, policies and conservation mechanisms that can enable their future protection and repair. Eight species of shellfish were identified as developing complex, three-dimensional reef systems over large scales in intertidal and subtidal areas across tropical, subtropical and temperate Australia. A dramatic decline in the extent and condition of Australia’s shellfish reef ecosystems occurred during the mid-1800s to early 1900s in concurrence with extensive harvesting for food and lime production, habitat modification, disease outbreaks and a decline in water quality. Despite early attempts during the late 1800s to curb over exploitation and repair degraded reefs through protection, primitive aquaculture and enhancement, living examples of shellfish reefs are now rare. Only one Ostrea angasi reef is known to exist that is comparable in size to reefs historically commercially fished, compared to at least 118 previously known locations. Out of the 60 historically fished locations identified for Saccostrea glomerata, only five are known to still contain commercially harvestable sized reefs. The introduced oyster Crasostrea gigas is increasing in reef extent, whilst data on the remaining five reef-building species is limited, preventing a detailed assessment of their current status. Our knowledge of the extent, physical characteristics, biodiversity and ecosystem services of natural shellfish reefs in Australia is extremely limited. Australia is well equipped to reverse the decline of shellfish reef ecosystems with a number of state and federal protection laws, international conventions and management mechanisms already in place, all of which can be used to help protect remaining reefs and aid in future recovery. Several restoration projects have recently begun as awareness of historical loss grows amongst the community and groups become motivated to implement repair. As momentum continues to grow, Australia could serve as a long-term model for other regions that may currently have limited understanding of their shellfish reefs ecosystems but wish to work towards their future conservation. Data to be made publicly available with publication of manuscript by end 2018.
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These files contain the metadata adopted and MATLAB code edited as well as visual plots generated in the Hongkun Honour's project. The data mainly includes the shipboard ADCP data and vertical cast type of Triaxus data collected from RV Investigator during the voyage IN2016V04 and IN2018T01 and satellite data (chlorophyll, sea level anomaly & sea surface temperature) collected from the IMOS website on the study region. The data was processed in MATLAB and then used to find visualization results, with the ultimate aim of exploring the potential of Triaxus in biogeochemistry.
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Voyage IN2019_V04 contributed an additional 29,000 kms2 of seafloor survey data to the Coral Sea knowledge base. From this new bathymetric data individual seamounts have been extracted and have been classified to the Geoscience Australia Geomorphology Classification Scheme. This dataset contains two layers representing the classification layers- 1) Surface (Plain, Slope, Escarpment) and 2) fine scale Geomorphology of the seamount for the Calder Seamount. Two classification layers are available for each seamount: 1) Surface (Plain, Slope, Escarpment) and 2) fine scale Geomorphology This parent record contains links to child records describing collections from seven (7) seamounts: • Fregetta Seamount • Mellish Seamount • Sula Seamount • Lexington Seamount • Kenn Seamount • Calder Seamount • Cassowary Seamount Data from individual seamounts are available through each record, or as a single data package in the 'Online Resources' section of this record.
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Short-tailed shearwater stable isotope data, nitrogen and carbon. This data was collected to document dietary trends.
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NOTE THIS IS AN ARCHIVED VERSION OF THE GLOBAL FISHERIES LANDING DATA AND MAY BE INCOMPLETE. The current version of the data is available from https://metadata.imas.utas.edu.au/geonetwork/srv/eng/catalog.search#/metadata/5c4590d3-a45a-4d37-bf8b-ecd145cb356d and should be used for all future analyses from 16/01/2019. For any questions about version changes to this dataset, please contact the Point of Contact nominated in this record. Global fisheries landings supplied by a number of agencies (FAO/UN, CCAMLR, NAFO, ICES etc) are mapped to 30-min spatial cells based on the range/gradient of the reported taxon, the spatial access of the reporting country's fleets, and the original reporting area. This data is associated with types of fishing gears. Estimates of illegal, unreported and unallocated landings are included as are estimates of the weight of fisheries products discarded at sea. Mapping the source of fisheries capture allows investigation of the impacts of fishing and the vulnerability of fishing (with its associate food security implications) to climate change impacts.
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The threatened status of shellfish reefs has been well established globally (e.g Beck et al 2011) however the ecological consequences of these losses is still largely unknown. In Australia, shellfish reefs are one of the most imperilled marine habitat types (Gillies et al 2018), due to historical overharvest and widespread eutrophication of coastal waters through the use of fertilizers, livestock and human waste. Marine bivalves are important ecosystem engineers providing habitat, shelter and a food source for other species in benthic soft-sediment environments. In addition, filter-feeding bivalves link benthic and pelagic components of ecosystems through filtration and excretion. Through their filter feeding, they produce large amounts of faeces (digested seston) and pseudofaeces (rejected particles bound up in mucus) which are deposited on the benthos. This process brings energy and nutrients from the pelagic system to the benthic system (bentho-pelagic coupling). The removal of large quantities of seston can serve an important ecosystem function by improving water quality and clarity. The filtration of water performed by bivalves has been demonstrated to reduce water turbidity, improving light penetration and thereby enhancing growing conditions for seagrasses (Wall et al 2008). In systems where healthy populations of bivalves remain, they can filter a volume equivalent or larger than the entire estuary volume within the residence time of the water (zu Ermgassen et al 2013). While such densities of oysters are rare today, this highlights the critical ecosystem services that are lost when oyster reefs decline. Furthermore, it demonstrates the potential functions that can be regained through oyster reef restoration. Given the increasing awareness of the decline of these ecosystems, interest in restoration efforts to restore critical ecosystem functions has been growing. However, conservation and restoration decision making is underpinned by reliable quantification of relevant ecosystem services (zu Ermgassen et al 2016). For example, there are plans to restore some of the natural oyster reefs of Sydney Rock Oyster (Saccostrea glomerata) in Port Stephens, New South Wales. One of the main drivers motivating this restoration project is restoring lost ecosystem services. The filtration rates of Australian oysters has been demonstrated in aquarium studies using filtered water augmented with algae, yet little is known about filtration and biodeposition rates of oysters using raw seawater. In this study, we provide the first evaluation of the filtration and biodeposition rate of four species of bivalves using raw seawater, providing a proxy for natural biodeposition rates. As such, this study provides a first indication of the filtration/nutrient cycling function that may be restored following oyster restoration efforts.
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Estimates of the value of habitats can provide an objective basis for the prioritisation of conservation and restoration actions. Bivalve habitats, three-dimensional structures made of high-densities of bivales (most often oysters or mussels), their shells and other organisms, used to be a dominant habitat found in temperate and subtropical coastal waters. These habitats, provide a suite of ecosystem services such as habitat provision and food supply for many species, substrate stabilisation and shoreline protection, and water quaility improvements through their filter feeding. Bivalve habitat restoration is increasingly seen as an opportunity to return lost ecosystem services. In Australia, there is growing interest in bivalve habitat restoration, but there is a knowledge gap in regards to the services they provide. Here, we determined the habitat value of a historically dominant oyster species in Australia, Saccostrea glomerata. At remnant soft-sediment oyster reefs at four locations we estimated density, biomass, productivity and composition of mobile macroinvertebrate communities and compared these with adjacent ‘bare’ soft sediments, which typically replace ecologically extinct oyster reefs. The oyster reefs had a distinct assemblage of macroinvertebrates, with 30% higher densities, 5 times the biomass and almost 5 times the productivity of adjacent bare sediments. Infauna macroinvertebrate productivity was more than twice as high below oyster reefs, suggesting these reefs facilitate infaunal productivity. Crustaceans, an important food source for small fishes, were 13 times more productive on oyster reefs compared to adjacent bare sediments. These results demonstrate that oyster reefs provide an important habitat for macroinvertebrates and that restoration efforts are likely to provide significant returns in enhanced productivity.
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Policy and decision makers often seek guidance as to the benefits of conservation and repair of coastal seascapes, to justify and underpin any potential investments. Much is already known about the broad habitat and nursery values of seascapes among the science community, but there is also a need for estimation of clear and unambiguous market-based benefits that may arise from investment in repair. Recognising that this economic knowledge is imperfect for Australian seascapes, three case studies spanning tropical, subtropical and temperate environments explored the benefits in question. The case studies focus on saltmarsh habitats in particular, which have received very little investment in repair despite subtropical and temperate coastal saltmarsh listed as vulnerable ecological community under Australian Federal legislation. A subset of economically important species and conservative judgments were used to characterise the minimum potential economic benefit. For each of the case studies the conclusion was that while the biological information will remain imperfect, the business case for investment in the repair and conservation of coastal seascapes is compelling. We outline priorities for further research to make the business case more tangible to policy makers, stakeholders and the general public.
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Voyage IN2019_V04 contributed an additional 29,000 kms2 of seafloor survey data to the Coral Sea knowledge base. From this new bathymetric data individual seamounts have been extracted and have been classified to the Geoscience Australia Geomorphology Classification Scheme. This dataset contains two layers representing the classification layers- 1) Surface (Plain, Slope, Escarpment) and 2) fine scale Geomorphology of the seamount for the Cassowary Seamount. Ongoing research with this survey data will provide new insights into the detailed geomorphic shape and spatial relationships between adjacent seabed features. This information will be released in future publications to show the potential of how the scale of such seafloor data can be used for predictive habitat modelling when analysed with the biological data overlays.