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.

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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]