Health authorities warn people not to eat fish and shellfish from the Mindarie marina.
The WA Health Ministry said fish, crabs or shellfish collected from the marina should not be consumed, after recent tests confirmed potentially toxic microscopic algae at very high levels.
Richard Theobald, Executive Director of Active Environmental Health, said that the tiny microscopic seaweeds, known as Alexandrium spp, could cause paralytic shellfish poisoning.
"These algae, which are not visible to the naked eye, can produce a very strong neurotoxin which could be absorbed by filterfish shellfish and possibly consumed by crabs and fish to a lesser extent. cooking procedures will not destroy these toxins, "he said.
"In the worst case scenario, PSP can cause muscle paralysis in people who eat infected shellfish, crab or fish from the marina.
"People who consume wild shellfish, crabs or fish collected from the Mindarie marina may also experience symptoms such as tingling or numbness of the lips, toes and toes, nausea or vomiting, decreased balance, dizziness, speech, vision, weakness, difficulty in swallowing or breathing, loss of fluid and diarrhea. "
He said that anyone who had eaten shellfish, crabs or fish collected from the marina and experienced any of these symptoms should seek urgent medical attention, especially if he felt some breathing discomfort. They should not reject the useless parts of mussels or other shellfish in case they need to test.
Shellfish include oysters, mussels, mussels, monkeys, scallops, scallops and razor.
The department stated that, as a general rule, people should avoid eating wild shellfish that are harvested, as safety can not be guaranteed. This is particularly true for rivers, estuaries or other waterways where there is an increased likelihood of inputs of pollutants or nutrients that could lead to increased growth of tiny algae.
Mr Theobald said shellfish farming purchased in WA's supermarkets and other WA stores was unaffected, as there was a strict quality assurance program to ensure that it is safe for human consumption.