State Government and fishers respond to Swan River algal bloom

We are working closely with a select group of volunteer recreational fishers and other government agencies to monitor the Alexandrium minutum algal bloom that has spread through the mid to upper reaches of the Swan River over the course of the last four weeks.

The Department of Health’s latest warning advises people not to eat shellfish, crabs and fish from the Swan River from Pelican Point and Como Jetty upstream to Maali Bridge Park, Herne Hill, after Alexandrium minutum, a potentially toxic microscopic algae had been detected in the water at elevated levels since early March.

While this type of algae has been found in the river before, its current high concentration is likely due to favorable weather and water conditions. It is not known how long the bloom will persist, but Department of Biodiversity, Conservation and Attractions (DBCA) environmental officers will continue to monitor algae levels within the river and provide results to the Department of Health.

The algae, invisible to the naked eye, can produce a toxin which can affect shellfish and crabs and fish which if consumed by humans, can potentially cause a range of medical symptoms including vomiting, dizziness and difficulties with breathing. More information can be found on this frequently asked questions flyer.

To ensure the situation and risks are understood, DBCA with the assistance of our scientists, ‘Bream Master’ recreational fishers and Murdoch University are assisting in collecting mussels, blue swimmer crabs and black bream in the Swan River. These species will then be tested for toxins to increase our understanding of the potential impacts of Alexandrium minutum upon these species.

Please remember to check health warnings on the Department of Health website before you go fishing in the Swan River. To assist in monitoring the situation, fishers should report any signs of sluggish or distressed fish to our FishWatch phone line on 1800 815 507.