Mystery toxic foam on South Australia’s Fleurieu Peninsula beaches identified

The cause of a strange toxic foam at SA beaches, which killed wildlife and caused allergic-type responses in humans, has been identified.

The cause of a mystery Fleurieu beach foam killing wildlife and causing illness in humans has been identified.

The Environment Protection Authority has received test results identifying the species Karenia mikimotoi as the cause of the microalgae bloom on the Fleurieu Peninsula.

Over the past week, yellow-toned foam was seen across beaches on the Fleurieu from Cape Jervis to Encounter Bay.

Several marine animals, including multiple species of fish, sea dragons and octopus were seen washed up on the beach and beach users also reported flue-like symptoms.

A sludge-coloured foam and dead fish have been sighted on the beaches of Waitpinga Point to Victor Harbor. Picture: Facebook

Waitpinga Beach was closed after surfers reported feeling ill. Picture: Aden Hill

The EPA confirmed the algae bloom was toxic to fish and can cause mass mortalities of marine species while causing flu-like symptoms in humans.

Human exposure, including through breathing in algae particles, can cause respiratory and eye irritation or skin rashes in some people, while ingestion could cause stomach upsets or flu-like symptoms, the EPA said.

Environment minister Susan Close urged people to avoid the water and shoreline along the affected beaches.

She said the EPA would continue to monitor the microalgae bloom and beaches would reopen as the bloom dissipates.

“If people do come into contact with the microalgae, please follow the health advice and wash it off with fresh water,” she said.

Several marine animals, including multiple species of fish, sea dragons and octopus were seen washed up on the beach. Picture: Facebook

The algae bloom can cause mass mortalities of marine species while causing flu-like symptoms in humans. Picture: Facebook

“With temperatures, including water temperatures, continuing to rise as part of climate change, we need to remain vigilant for these type of events and I thank everyone who took to the time to report the bloom to authorities.

SA Health’s Principal Water Quality Adviser David Cunliffe said Karenia mikimotoi was toxic to fish but not humans.

“In humans, exposure – including through breathing in algae particles broken up by the surf and wind – can cause general allergic-type responses, including respiratory and eye irritation or skin rashes in some people, while ingestion could cause stomach upsets or flu-like symptoms.

He said symptoms disappear when the exposure stops or following washing in clean water and there were no long-term effects.

Waitpinga Beach and Parsons Beach will remain closed until further notice and people should adhere to the warning signs located at other council-run beaches.

The last time a large event of this type of algae was recorded in SA was in 2014 in Coffin Bay.

The event has been driven by an ongoing marine heatwave, with marine water temperatures currently 2.5C warmer than usual, as well as relatively calm marine conditions with little wind and small swell.

Originally published as Mystery toxic foam on South Australia’s Fleurieu Peninsula beaches identified