The Acting Director of Public Health, Dr Mark Veitch, has advised that new test results on mussels from Spring Bay show levels of toxins now exceed the safe human consumption level of 0.8 mg/kg.
Dr Veitch said that the affected product had not been released to the market.
"This is the first time this season toxins have exceeded the limit.
"Public Health has responded by immediately closing the Spring Bay growing area for commercial shellfish growing.
"The elevated toxin levels were detected because of a recently implemented increased testing regime along the East Coast.
"One growing area had been closed earlier as a precaution after heavy rain caused farm run-off in the area," Dr Veitch said.
Toxic algae have been commonly detected in Tasmanian waters since 1980.
Non-commercial shellfish growing areas are not routinely monitored so Public Health advises it is unsafe to eat shellfish in unmonitored areas.
For more information visitwww.dhhs.tas.gov.au/peh/tsqap/recreational_harvesting_of_bivalve_shellfish