Microalgae toxic to fish identified as cause of bloom linked to Fleurieu Peninsula marine deaths
Topic:Environment
11m ago11 minutes agoMon 24 Mar 2025 at 8:41pm
dead octopus about the length of six mobile phones on a beach
A dead octopus washed up at Basham Beach during the algal bloom. (ABC News: Caroline Horn)
In short:
The Environment Protection Authority has identified the species Karenia mikimotoi as the cause of an algal bloom on Fleurieu Peninsula, where dozens of dead marine creatures washed up at Encounter Bay and Basham Beach.
Several people reportedly experienced sore eyes, coughing and blurry vision after visiting beaches two weekends ago.
What's next?
The beaches will remain closed until further notice.
A toxic microalgae linked to fish and octopus deaths along South Australian beaches has been identified, with environment authorities blaming the bloom on a "marine heatwave" and "warmer-than-usual" sea temperatures.
The Environment Protection Authority (EPA) has identified the species Karenia mikimotoi as the cause of the bloom on Fleurieu Peninsula, where dozens of dead marine creatures washed up at Encounter Bay and Basham Beach.
Several people reportedly experienced sore eyes, coughing and blurry vision after visiting Waitpinga and Parsons beaches two weekends ago before the environment department closed both sites.
The EPA suspected a microalgal bloom as the cause, but said testing would have to be conducted to identify the species.
The SA government today said results had identified Karenia mikimotoi, which SA Health said was "toxic to fish but not humans".
A large build up on cloud like foam on a beach.
The EPA said swell broke up the algae, causing foam. (ABC News: Caroline Horn)
Environment Minister Susan Close said the microalgae had flourished in calm sea conditions, and that the bloom had been caused by an "ongoing marine heatwave" in which water temperatures were 2.5 degrees Celsius "warmer than usual".
"The EPA will continue to monitor the microalgae bloom and beaches will reopen as soon as it dissipates," she said.
The department's principal water quality adviser David Cunliffe said exposure, including via inhaling algal particles, could 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".
"These symptoms disappear when the exposure stops or following washing in clean water. There are no long-term effects," he said in a statement.
"In general, people should avoid contact with discoloured fresh or marine water. If they do enter this water they should take care to wash in clean water afterwards."
A dead fish with black and white stripes lays in the sand
SA Health said the algae was toxic to fish but not to humans. (ABC News: Caroline Horn)
Waitpinga and Parsons beaches will remain closed until further notice, the government said.
"I would encourage people to avoid the water and shoreline along the affected beaches," Ms Close said.
"If people do come into contact with the microalgae, please follow the health advice and wash it off with fresh water."
The government said algal blooms of the kind that have been detected along the Fleurieu had been recorded in marine waters since the 1930s, and caused "mass mortalities of fish, shellfish, and other invertebrates".
It said the last such event in South Australian waters involving this type of algae was at Coffin Bay in 2014.
Posted11m ago11 minutes agoMon 24 Mar 2025 at 8:41pm
Copy link
X (formerly Twitter)