Collecting and eating wild shellfish can cause illness

Collecting and eating wild shellfish can cause illness

This advice applies to wild shellfish.

Shellfish for sale in shops and restaurants are safe to eat.

Public Health Advice

  • This advice is about collecting and eating wild shellfish.
  • There is always a risk of illness from eating wild shellfish that you have collected.
  • Poor water quality and harmful algal blooms increase the risk of illness from eating wild shellfish.
  • Shellfish collected in Hobart’s Derwent Estuary and Launceston’s Tamar Estuary are always unsafe to eat because the shellfish concentrate the heavy metals present in these waters.

Shellfish from shops and restaurants in Tasmania are safe to eat. This is because the safety of commercially grown shellfish is closely monitored.

There is always a risk to your health from eating wild shellfish that you have collected.

Water quality affects shellfish quality.

Poor water quality can be caused by rainfall run-off, sewage and other outfalls. It is often hard to know if water quality is poor.

Shellfish are filter feeders. They feed by filtering large volumes of water.  Bacteria, viruses, other harmful germs, and metals in poor quality water can build up in the shellfish.

It is always unsafe to eat wild shellfish from:

  • near marinas or other places where boats discharge waste
  • near sewage, industrial or stormwater outfalls
  • in areas near septic tanks
  • in places affected by recent heavy rain
  • from the Derwent and Tamar Estuaries.

You can get gastro illness if you collect and eat wild shellfish like oysters, mussels, clams, pipis, cockles and wedge shells from where the water quality is poor.

There is an extra risk to your health when there is a harmful algal bloom

  • Harmful algae in the water can affect shellfish.
  • Large numbers of harmful algae in water are called a harmful algal bloom.
  • You cannot see any change to the water when a harmful algal bloom is present.The water looks and smells normal.
  • Some types of naturally-occurring algae make toxins. When shellfish feed on these algae the toxins build up in their flesh.
  • The harmful algal bloom can persist for weeks and the shellfish take even longer to clear the toxins from their flesh.
  • Shellfish can be affected even in places where there are no warning signs.

Do not collect and eat wild shellfish when there is a harmful algal bloom warning.

Toxic shellfish during a harmful algal bloom can cause serious illness

  • You can become seriously ill with shellfish poisoning if you collect and eat shellfish with toxins from a harmful algal bloom.
  • Shellfish toxins are not destroyed by freezing or cooking.
  • Symptoms of shellfish poisoning can occur from minutes to hours after eating shellfish.
  • Paralytic shellfish poisoning is the most common form of shellfish poisoning in Tasmania.
  • Shellfish poisoning symptoms include:
    • tingling or numbness
    • weakness
    • blurred vision
    • difficulty breathing
    • vomiting
    • diarrhoea.

Get urgent medical attention if you have these symptoms after eating wild shellfish

Oysters, mussels, clams, pipis, cockles, wedge shells, abalone, scallop roes and the intestines and livers of rock lobster can be affected by toxins.

Visit Do not eat wild shellfish for more information on shellfish quality and current harmful algal blooms or call the Public Health Hotline – Tasmania on 1800 671 738.

February 2021