An Australian state has temporarily closed two beaches after dead fish and an unusual off-white foam washed ashore, with surfers reporting health issues, officials said on Tuesday.
Authorities suspect a microalgal bloom, triggered by unusual weather conditions, is responsible for the foam, the marine life deaths, and the reported human illnesses, according to Sam Gaylard, principal scientific officer at the South Australian Environment Protection Authority.
“This scale of bloom is unusual. While we do see isolated blooms under certain weather conditions, one of this magnitude is quite rare,” Gaylard said.
Waitpinga Beach and nearby Parsons Beach, located south of Adelaide, have been off-limits since Monday due to what the Department for Environment and Water described as a “fish mortality event.” Officials assured the public that the beaches would reopen as soon as conditions allow.
Dozens of dead fish have reportedly washed ashore, while surfers have been experiencing symptoms such as sore eyes, sore throats, and coughing after being in the water. Local surfer Anthony Rowland, who surfed at Waitpinga on Saturday, said he and his friends began coughing while in the water. After sharing his experience online, he received numerous responses from others with similar symptoms.
Marine scientists collected water samples on Monday to analyze the foam, which is a byproduct of the toxic organisms’ decay. However, identifying the specific organism may take until the end of the week, Gaylard said.
The bloom could have been triggered by an extended period of hot, dry weather, combined with low tides and little wind, he explained. Since Sunday, stronger swells have increased turbulence in the water, which may help disperse the algae but also create more foam.
“At this stage, we don’t know how long it will last,” Gaylard added.
Authorities are closely monitoring the situation and have advised the public to stay away from the affected beaches until further notice. Officials are also urging anyone experiencing symptoms after being in the water to seek medical advice and report their condition to health authorities.
Meanwhile, environmental scientists are working to determine the full extent of the bloom’s impact on marine life and whether additional beaches may be affected. While microalgal blooms occur naturally, large-scale events like this can disrupt local ecosystems, deplete oxygen levels in the water, and pose risks to both wildlife and humans.
Experts say that if the bloom is found to contain harmful toxins, it could take days or even weeks for conditions to return to normal. Cleanup efforts may be necessary if large amounts of dead fish continue to wash ashore.
Local businesses, particularly those reliant on tourism and water sports, are also feeling the effects of the closures. Some surf schools and tour operators have temporarily suspended operations, while nearby cafes and shops have reported fewer visitors.
The South Australian government has assured residents that they are prioritizing public health and environmental safety, with ongoing water testing and aerial surveys to track the spread of the algae. Further updates on beach reopenings and test results are expected by the end of the week.
