South Australia (SA) is currently experiencing one of the largest-scale algal bloom events ever recorded in Australian waters. The harmful algal bloom (HAB), first detected in March 2025, is a marine disaster, similar to ‘an underwater bushfire’, with an extensive marine mortality rate.

This report outlines the findings and recommendations from an inquiry into the causes, frequency, scale and duration of recent algal blooms in South Australian marine and coastal environments.

Structure of the report

• Chapter 1 provides details of the inquiry and background information on the harmful algal bloom in SA.
• Chapter 2 outlines the key contributing factors for the bloom, and discusses current and future management strategies, forecasting and prevention strategies, and the international experience of Karenia mikimotoi blooms.
• Chapter 3 outlines the role of the SA and Commonwealth Governments in the response to the harmful algal bloom.
• Chapter 4 sets out evidence relating to the ecological, economic and social impacts of the algal bloom on marine biodiversity and ecosystem health.
• Chapter 5 continues to discuss the ecological, economic and social impacts of the algal bloom on industries which rely on ocean health, and on regional and coastal communities.
• Chapter 6 sets out the human health impacts of the algal bloom.
• Chapter 7 sets out the cultural and economic impacts on First Nations communities.
• Chapter 8 sets out the committee view and recommendations.

Key recommendations

• Coordination and communication between the Commonwealth and South Australian Governments, including the involvement of local government.
• Preparedness for harmful algal blooms.
• Financial support for marine industries.
• Ecological restoration and recovery efforts.