It is hoped that recent strong winds and ocean swells will help break up the harmful algal bloom affecting parts of South Australia. Further monitoring is needed in the coming days to determine what effect the storm conditions will have on the algal bloom, including its potential movement along South Australia’s coast. Higher sea temperatures are among the conditions that have caused the algal bloom. Sea temperatures are dropping but still above average for this time of the year. It is hoped cold fronts pushing up from the south will bring temperatures down further.
What are the effects of the algal bloom?
The Karenia mikimotoi algal bloom has caused discoloured water and foam along parts of Fleurieu Peninsula, Kangaroo Island and the southern coast of Yorke Peninsula. It has affected various marine wildlife, including fish, sharks, rays, seahorses and other species with gills.
Why has it appeared?
Experts believe the bloom is being driven by a marine heatwave – with sea temperatures about 2.5°C warmer than usual – combined with calm conditions, light winds and small swells. The last large event of this type of algae recorded in SA was at Coffin Bay in 2014.
How long might the bloom last?
Similar blooms around the world have lasted from a week to several months, depending on wind, rain and ocean temperatures. This one is expected to persist until strong westerly winds arrive, which historically happens at the end of April. However, persistent high pressure systems have delayed these winds.
Is the bloom harmful to people?
Karenia mikimotoi does not cause long-term harmful effects in humans. However, exposure to discoloured or foamy water can cause short-term skin or eye irritation and respiratory symptoms, including coughing or shortness of breath. These symptoms usually resolve within several hours of leaving the beach. Swallowing water affected by the algal bloom can cause gastrointestinal symptoms, including vomiting, diarrhoea and abdominal cramps.
What should I do if I experience symptoms?
If you are outdoors and experience irritation, go indoors, close windows and rinse exposed skin. If symptoms are more severe or do not resolve, seek medical advice from a GP and call 000 if it is a medical emergency.
Can I swim or walk on the beach?Avoid swimming or surfing in discoloured water, foam or where marine life is dead or in poor healthIf you experience irritation, go indoors, close windows and rinse exposed skin; seek medical advice if symptoms persist or call 000 in an emergencyDo not touch or eat dead or dying fish, shellfish or marine wildlifeFish caught alive are safe to eatFollow beach signage and directions from NPWS rangersIs it safe to eat seafood from affected areas?Do not eat dead or dying fish, cockles or other marine life found on the beachFish caught live are safe to eatReport fish deaths to FISHWATCH on 1800 065 522Commercial pipi harvesting was closed on 16 April from the Murray Mouth to 10km south of the mouth, to prevent packaging of dead or dying pipis.Further closures were implemented on 19 May at American River, Port Vincent and Stansbury oyster harvesting areas.Ongoing testing in open harvest areas continues to ensure product safety.What is being done about the bloom?Government agencies, including the Department for Environment and Water, the Environment Protection Authority, the Department of Primary Industries and Regions and SA Health are monitoring the situationSigns are in place at public entry points to affected beaches, and National Parks beaches remain openNothing can be done to dilute or dissipate the bloom naturallyIs quarry sand contributing to the bloom?Quarry sand is tested to meet strict environmental standards to ensure it is compatible with existing sand on the beach. As the algal bloom is naturally occurring, there is no link between it and the delivery of external quarry sand to West Beach and Henley Beach.Are desalination plants contributing to the bloom?No health issues are known to be associated with brine discharged from desalination plants and brine is not linked to increased algal growth. All marine desalination plants operated by SA Water are regulated by the Environment Protection Authority, which ensures appropriate management of brine outflow.Who should I contact about dead wildlife?Who should I contact with health questions?Where can I read more?