
South Australia’s coastline is grappling with a toxic algal bloom that has now reached Adelaide’s beaches, exacerbating public concern over an environmental disaster that has persisted since March. The bloom, caused by the harmful Karenia mikimotoi algae, has already devastated marine life across regions including the Fleurieu Peninsula, Kangaroo Island, Yorke Peninsula, and the Coorong.
Following a major storm on June 24, the situation worsened as masses of dead marine life, including rays and fish, began washing ashore from north of Grange jetty to south of Christies Beach Surf Club. Dr. Michael Bossley, a marine biologist, noted, “Until that time, it hadn’t hit metro Adelaide. Suddenly, the people of Adelaide and the government and just about everybody are doubling down on their concern.”
Government Response and Environmental Impact
This week, South Australia’s Environment Minister, Dr. Susan Close, admitted the state was “helpless in the force of nature,” acknowledging that the bloom is unlikely to dissipate soon and could reoccur. “The algal bloom is a dynamic situation. Its movement depends on weather and water conditions, and [that] makes the effect on people and wildlife unpredictable,” she stated.
The state government had hoped that storms and cooler water temperatures would mitigate the bloom. However, the opposite has occurred, with storms facilitating the algae’s spread to new areas. Recent testing confirmed the algae’s presence in West Lakes, a suburb in Adelaide’s west, with further investigations underway at 14 additional sites, including the Port River, home to the Adelaide dolphin sanctuary.
Timeline of the Algal Bloom Crisis
- September 2024: A marine heatwave raises sea surface temperatures by 2.5°C above average off South Australia’s coast.
- 18 March 2025: Mysterious sea foam appears on Fleurieu Peninsula beaches, causing illness among surfers and marine life deaths.
- 25 March 2025: High concentrations of Karenia mikimotoi algae are identified in water samples.
- 13 May 2025: Over 200 marine species are reported dead, with the bloom extending over 150 kilometers of coastline.
- 24 June 2025: Abnormal tides and storms result in widespread fish deaths along Adelaide’s metropolitan coastline.
- 1 July 2025: Algae is confirmed in West Lakes, raising concerns about its spread to urban estuaries.
Community and Economic Concerns
Since the bloom’s onset, approximately 8,000 dead marine animals have been recorded, affecting 390 species as part of the SA Marine Mortalities project. OzFish, a fishing conservation charity, has been instrumental in this citizen science effort. “We know that sponge gardens and shellfish beds – mussels, native oysters, razor fish – a lot of those areas are now considered graveyards, because they’ve been completely wiped out by the bloom,” said Brad Martin, OzFish South Australian project manager.
The potential for the algae to enter urban estuaries and waterways is a significant concern. “The Onkaparinga, West Lakes, and the Port River are all areas of concern; they’re popular recreational fishing sites, with access to the ocean,” Martin added. Asher Dezsery, executive officer for RecFish SA, highlighted the dire impact on fisheries and tourism. “The fish were being poisoned, they’re being choked to death, and they need to bounce back as quickly as possible,” he said, noting that some fisheries, like Goolwa pipis, have seen mortality rates of 37%.
Future Implications and Climate Change
On Friday, the state government convened with commercial fishers, tourism operators, and local councils to devise a recovery plan for when the bloom eventually recedes. While sea surface temperatures in shallow waters are declining, marine heatwave conditions persist in deeper waters around Kangaroo Island and the southern Yorke Peninsula.
Marine heatwaves, which triggered the bloom, are a global concern linked to climate change. “It’s climate change happening,” Dr. Bossley remarked, underscoring the broader environmental implications.
As South Australia continues to navigate this crisis, the focus remains on mitigating the bloom’s impact and preparing for potential future occurrences. The state’s response and recovery efforts will be critical in addressing both the immediate and long-term challenges posed by this environmental threat.