IMAS Metadata Catalogue
TROPHIC DYNAMICS
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This record provides an overview of the NESP Marine and Coastal Hub Emerging Priorities project "A trophic-ecology based tool to assess and manage HAB impacts on marine ecosystems". For specific data outputs from this project, please see child records associated with this metadata. -------------------- South Australia’s 2025 harmful algal bloom (HAB) caused mortality across multiple trophic levels, from primary producers to top predators. This highlighted the need for tools that assess reef ecosystem condition and recovery using food-web structure, not only species counts or biomass estimates. This Emerging Priorities project will develop a trophic integrity framework for assessing subtidal reef condition across South Australia’s marine estate. The framework will support development of a Normalised Reef Status Index (NRSI) based on relative biomass across trophic levels, using biodiversity datasets from Reef Life Survey and the Australian Temperate Reef Collaboration, along with stereo-BRUV surveys and long-term habitat, plankton and water-quality monitoring. The project will model relationships between reef condition and environmental, disturbance and management drivers, enabling assessment of the 2025 HAB and marine heatwave impacts, recovery trajectories, and areas most vulnerable to future events. It will integrate existing and new biodiversity datasets with trophic and spatial analyses to provide a science-based assessment of subtidal reef condition. A web-based decision-support tool will be used to visualise reef condition, disturbance impacts and recovery, and to explore management options such as spatial protection, habitat restoration, fishing closures and rezoning. A technical report with management recommendations will support the SA HAB Science Program, state and Commonwealth agencies, marine park management, and public engagement. Outputs • Quantitative models linking trophic integrity indicators (including the NRSI) with environmental and management drivers [modelling framework] • Spatial prediction and vulnerability maps identifying reef areas most affected by the 2025 HAB and areas most susceptible to future disturbance events [dataset] • Interactive web-based decision-support dashboard for visualising reef condition, disturbance impacts and recovery trajectories, with scenario-testing functionality [tool] • Final technical report [written]
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The Tasman Fracture Marine Park (TFMP), located off the southwestern coast of Tasmania, is an ecologically and culturally significant area characterised by dynamic and diverse marine ecosystems ranging from abyssal plains to rocky reefs. This region is a productivity hotspot due to the convergence of ocean currents and upwelling processes (Ridgway and Ling, 2023), which supports rich biodiversity, including endangered species such as the shy albatross (Thalassarche cauta), the migratory short-tailed shearwater (Ardenna tenuirostris), the endemic Australian fur seal (Arctocephalus pusillus doriferus) and expanding populations of long-nosed fur seal (Arctocephalus forsteri). The primary objectives of this multidisciplinary research were to quantify the physical water properties within the TFMP to establish baseline environmental conditions; map mesopelagic (midwater) productivity using acoustic equipment; characterise the foraging behaviour and habitat use of key marine predators through biotelemetry devices; investigate the diet of seabird and fur seal species to understand pelagic food web interactions; and assess cetacean species diversity, temporal patterns, and quantify underwater noise using passive acoustic monitoring. To achieve these objectives, the study employed a combination of methodologies (see 'Lineage' section for full methodology): • Oceanographic analysis provided insights into the climatology and productivity patterns influenced by the East Australian Current and the Zeehan Current. • Biotelemetry tracking of seabirds and seals provided data on foraging behaviour and habitat use of key predators. • Scat sampling of predator species combined with DNA metabarcoding techniques were utilised to identify prey species and provide detailed dietary profiles. • Underwater acoustic recorders were used to monitor cetacean vocalisations and assess underwater noise levels. In summary, this research provides essential baseline data and insights into the complex interactions within the TFMP's ecosystems. The findings emphasise the need for integrated, multidisciplinary approaches to marine conservation. By addressing the identified challenges and implementing the recommendations, managers can enhance the resilience of the TFMP, ensuring the protection of its unique biodiversity in the face of environmental changes.
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Data is PCR amplification results of southern rock lobster (Jasus edwardsii) faecal material tested for sea urchin DNA (using unique primers for Centrostephanus rodgersii and Heliocidaris erythrogramma) in an attempt to determine in situ rates of consumption of sea urchins by lobsters. An efficient and non-lethal method was used to source and screen lobster faecal samples for the presence of DNA from ecologically important sea urchins. Lobster faecal samples were collected from trap caught specimens sourced in winter & summer seasons over 2 years (2009-2011) within two no-take research reserves; declared specifically for the purpose of rebuilding large predatory-capable lobsters to assess the potential for predator-driven remediation of kelp beds on rocky reefs extensively overgrazed by sea urchins (North Eastern Tasmania) and reefs showing initial signs of overgrazing (South Eastern Tasmania). Data for molecular assays showed high variability in the proportion of lobsters testing positive to sea urchins, with significant variability detected across different years and seasons but this was found to vary depending on different lobster size-classes. Sea urchin DNA was also amplifiable from sediments and urchin faeces collected from the reef surface where urchins occurred in high abundance. Furthermore, positive sea urchin DNA assays were obtainable from lobster faeces after lobsteres were fed sediment and urchin faecal material. Rates of predation obtained with genetics tests can also be compared to independent rates of urchin losses given known lobster abundances within research reserves (and at control sites). Data of changes in urchin abundances and lobster abundances are therefore also lodged as part of this record.