Charles Darwin University (CDU)
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Relevant spatial datasets for mapping pressures were identified and collated. Pressures were categorised as resource extraction and use, pollution, habitat modification, climate, and ‘other’. Pressures included Commonwealth trawl fisheries effort, aquaculture infrastructure, location of oil and gas infrastructure, historical shipping and pollution data, location of historical seismic operations, cyclone intensity, spoil dumping, sewage outfalls, location of ports, and tourism operations. Two main pressure maps were derived i) an additive pressure hotspots map, which gives higher weight to areas with multiple pressures of high risk; and, ii) a multiplicative hotspot pressure map, which gives lower weighting to areas with multiple low risk pressures. Areas of high risk were identified, and thus possibly high benefit for management versus low risk or low associated benefit for mitigation. The information generated needs to be considered alongside robust species distribution data and interaction matrices for effective decision-making.
This database contains acoustic telemetry data for euryhaline elasmobranchs in northern Australian rivers. Data was collected 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'. An acoustic receiver array was deployed in the Adelaide River, and another in the Alligator Rivers (primarily the South Alligator River) to monitor the movements, habitat use and natural mortality of threatened river sharks (Glyphis species) and sawfishes (Pristis species). Receiver deployment data is available through the IMOS Animal Tracking Facility database (visit https://animaltracking.aodn.org.au/receivers/deployment and search for project 'NESP Northern Australian hotspots for the recovery of threatened euryhaline species'). Detection data is currently embargoed until end 2023.
Australia is home to a quarter of the world’s cartilaginous fishes (Class Chondrichthyes) with 328 species consisting of 182 sharks, 132 rays, and 14 chimaeras. Australia’s first Shark Action Plan aims to provide a comprehensive and consistent review of the extinction risk of all cartilaginous fishes (hereafter ‘sharks’) occurring in Australian waters, to provide a benchmark from which changes in population and risk can be measured, and to help guide management for their conservation. This Action Plan also serves to raise the profile of their diversity and conservation needs. This volume includes a taxa profile for each of the 328 species occurring in Australian marine and inland waters, including external territories. Each species’ extinction risk was assessed by applying the IUCN Red List Categories and Criteria at the national level. Assessments of extinction risk consider all available information on a species’ taxonomy, distribution, population status, habitat and ecology, major threats, use and trade, and conservation measures. The IUCN Red List Categories and Criteria utilise a series of thresholds to evaluate extinction risk based on population size reduction, geographic range, population size, or the probability of extinction. Species were assessed against the five Red List criteria; to qualify for one of the three threatened categories (Critically Endangered, Endangered, or Vulnerable), a species had to meet a quantitative threshold for that category in any of the five criteria. The overall status of sharks in Australia is characterised by a relatively low level of extinction risk and a high level of secure species. Of the 328 species, 12% are threatened (39 species: 22 sharks, 17 rays; no chimaeras are threatened); 10% are Near Threatened (32 species: 18 sharks, 13 rays, 1 chimaera); 70% are Least Concern (231 species: 123 sharks, 95 rays, 13 chimaeras); and, 8% are Data Deficient (26 species: 19 sharks, 7 rays, no chimaeras are Data Deficient). No species are Extinct or Extinct in the Wild. Each taxa profile specifies two sets of actions for a species: actions to address knowledge gaps, and actions to maintain, secure, and if necessary, recover the population. To improve the ability to accurately assess the status of species, and ultimately, better conserve and manage them, all species treated in this Action Plan require some knowledge gaps be filled. Knowledge gaps are divided into five themes, each of which improves the information base from which to assess status: taxonomy, distribution, population trend, life history, and connectivity. Conservation actions are provided for each species, regardless of the status assigned them in this Action Plan. While threatened species require immediate action to conserve, manage, and recover their populations, Least Concern species also require action to maintain their secure status. Data Deficient species require action to understand various aspects of their population, but since an assessment as Data Deficient acknowledges the possibility that future research may show that a threatened classification is appropriate, action is also needed to minimise or mitigate threats until such time as more information is available to show that the species is not threatened. Finally, an overarching recommendation is provided for each threatened species. This includes the recommendation that five species be considered for listing on the Environment Protection and Biodiversity Conservation Act (EPBC Act), three species be considered for up-listing, and two species be considered for down-listing. An additional 12 threatened species have been identified as priorities for data collection where further data are required to strengthen the evidence-base underlying their status determinations. These species are priorities for research and monitoring to provide data to support inferred or suspected population reductions or continuing declines identified in the Action Plan. The implementation of the recommendations and actions in this Action Plan will require an ongoing and enhanced investment in science and management which will help secure the future of Australia’s sharks, rays, and chimaeras.
Of the ~80 EPBC-listed Threatened and Migratory marine species known to occur in the North Marine Bioregion, 16 were identified as priority species through consultation with research end-users and experts. The priority group consisted of three sawfishes, two river sharks, Dugong, two inshore dolphins, six shorebirds and two turtles. Dwarf and then Green Sawfish had the most data gaps, indicating that these were the most poorly-known of the selected priority species in the North Marine Bioregion, and as such are a priority for research. These were followed (in order of data gaps) by the other river sharks and sawfishes, inshore dolphins, Hawksbill Turtle, Dugong, Olive Ridley Turtle, and shorebirds. Research assessing the relevance and impact of pressures was identified as a gap for all species. New data identified during the project can fill data gaps for all 16 species, and the analysis of these datasets can improve the accuracy of distribution maps, but new data collection is still required for all sharks and sawfishes, Hawksbill Turtle, and inshore dolphins to improve data coverage for distribution modelling and mapping. The gap analysis identified numerous new datasets, both published and unpublished, that are currently not incorporated into SPRAT profiles and distributions (see Table 5). This provided an opportunity to begin compiling and analysing this information to fill current data gaps, as well as identify targeted research needs for the future.
This database contains molecular data 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. Tissue samples were collected from all elasmobranchs for molecular analyses (population genetics and close-kin mark-recapture).