Domoic Acid (Amnesic Shellfish Poisoning)

What is domoic acid?

Domoic acid is a toxin created by certain types of red-brown algae that live in coastal waters. When these algae reproduce very quickly they form what is known as a harmful algal bloom and can create enough domoic acid to contaminate shellfish in the area. These may include mussels, clams and oysters, as well as the tomalley of lobsters and crabs.

People who eat these contaminated shellfish can get a very serious illness called amnesic shellfish poisoning.

What are the symptoms of amnesic shellfish poisoning?

Amnesic shellfish poisoning can be very serious.

It usually starts with digestive symptoms such as an upset stomach, cramps, throwing up or diarrhea. These symptoms usually appear in the first few hours after eating contaminated shellfish.

It can then move on to symptoms affecting the nervous system within the next three days. These can include headache, confusion, dizziness, disorientation and memory loss. This memory loss may remain, even after the other symptoms go away.

In severe cases, a person may feel weak, have seizures, become paralyzed or even die.

What should I do if I think someone has amnesic shellfish poisoning?

If you think someone has eaten contaminated shellfish, call the Northern New England Poison center at 1-800-222-1222, chat online or text POISON to 85511.

How can I prevent amnesic shellfish poisoning?

State officials monitor domoic acid levels in shellfish, and will close an area to harvesting if there are dangerous amounts. Do not harvest or eat shellfish from a closed area. Cooking the shellfish will not make them safe to eat.

Stay safe by buying shellfish only from reputable stores, fish markets and restaurants.

You can get lists of areas closed because of domoic acid or other harmful algal blooms, such as red tide, from the Maine Department of Marine Resources and the New Hampshire Department of Environmental Services.