Since the middle of March 2025, South Australian coasts have been afflicted by a toxic algal bloom of unprecedented size and duration. The effects of the bloom on marine life have been devastating, with untold thousands of dead creatures, from tiny worms to large sharks, washing up on the beaches from Encounter Bay and Kangaroo Island to shores on both sides of Gulf St Vincent. Underwater surveys indicate that mortalities seen on the beaches are only a small fraction of what is happening off-shore.
As the bloom has progressed, various citizen science groups, independent researchers, university researchers and government departments have been working to monitor and understand the genesis, progression and effects of the toxic algal bloom. As a result of my background in zoology, comparative anatomy and physiology, pharmacology, and both cellular and systems neuroscience, it turns out that I am one of the few people around who has significant background knowledge of how the various algal toxins affect different cell types and organ systems is a wide range of marine creatures. Consequently, I have contributed directly to several citizen science projects and have spoken about the toxins at public forums.
Based on the talks I have given at public forums together with discussions with key citizen scientists, I have put together a comprehensive overview of how the different toxins in the current bloom cause their effects on various organisms, including fish, marine invertebrates and people.
The material here is under constant review as new information comes to hand and is updated accordingly. For example, in November 2025, a major new analysis revealed that the dominant dinoflagellate in the bloom is a species previously undocumented in South Australia and that this species is a major source of brevetoxin, leading to a re-assessment of some key elements of the bloom.
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