The Department of Health has updated its toxic algal bloom warning to include parts of the Canning River.
The update follows earlier health advice, warning people not to eat fish, crabs or shellfish collected from within the Swan River – from Pelican Point to Como Jetty and upstream to Tonkin Highway Bridge (this includes the commonly known areas of Matilda Bay, Perth Waters, Elizabeth Quay, Barrack Street Jetty, Claisebrook Cove, Maylands Yacht Club, Ascot Waters and Riverside Gardens).
Recent testing by the Department of Biodiversity, Conservation and Attractions (DBCA) has now identified elevated levels of the same, potentially toxic Alexandrium algae in the Canning River and the health warning has been extended to the area from the South of Perth Yacht Club to Como Jetty and upstream to Kent Street Weir.
The ingestion of toxins produced by this microscopic species of algae can produce a type of poisoning known as paralytic shellfish poisoning (PSP). Cooking will not destroy these toxins.
People who consume wild shellfish, crabs or fish collected from the affected area of the Swan River may experience symptoms including:
- tingling or numbness of the lips
- prickliness of the fingertips and toes
- nausea or vomiting
- impaired balance
- slurred speech
- double vision
- difficulty in swallowing or breathing
- loss of fluids and diarrhoea
In severe cases PSP may cause muscular paralysis in people who consume affected shellfish, crabs or fish. Shellfish includes oysters, mussels, clams, pipis, scallops, cockles and razor clams.
Anyone who has consumed shellfish, crabs or fish collected from the affected area of the Swan River and experiences any of these symptoms should seek urgent medical attention, particularly if they have difficulty breathing.
They should also retain uneaten portions of mussels or other shellfish to help determine a likely cause of any symptoms.
As a general rule people should avoid eating recreationally collected shellfish in rivers, estuaries or other waterways where there is an increased likelihood of contaminant or nutrient inputs that could lead to increased microscopic algae growth.
Farmed shellfish purchased in supermarkets and other commercial outlets in WA are not affected because there is a strict quality assurance program to ensure they are safe for human consumption.
Other recreational activities including swimming, skiing and boating in the Swan River are not affected by this microalgae species, but as a general rule swimming should be avoided in areas of discoloured water.
Health warning signs advising against crabbing, shellfish collection and fishing have been erected at key locations including jetties, boat ramps and key accessible foreshore areas within the affected region.
DBCA will continue to monitor algae levels within the Swan and Canning Rivers and will resample mussels and crabs for toxins within the next two weeks.
A map detailing affected waterways can be viewed on the DBCA website.