A significant harmful algal bloom (HAB), dominated by Karenia spp., has affected Gulf St Vincent, Spencer Gulf and adjacent waters in South Australia since March 2025. The bloom has been associated with substantial marine mortality, with large numbers of organisms from a broad range of taxonomic groups observed along the South Australian coastline, including species of commercial, recreational and ecological importance.
In response, the Government of South Australia implemented a substantial, coordinated program to assess the impacts of the HAB on key marine species and to provide information to support real-time fisheries management. SARDI's targeted fishing and dedicated survey program has generated field-based data to support the assessment, monitoring and management of South Australian marine fisheries. The program has incorporated targeted sampling by commercial fishers and dedicated scientific surveys across affected regions and key species, collecting information on abundance, distribution, size and age structure, recruitment, and other biological indicators.
Regular reporting of survey and commercial fishing data has supported the rapid evaluation of fishery status and informed ‘real time’ management responses. This presentation will describe the spatial and temporal development of the bloom, the monitoring and assessment programs established in response, and the resulting management actions, including the Recovery Roadmap. It will also provide an overview of current fishery status and outline the proposed SARDI monitoring and research program for 2026/27.