Interim Health Advisory on Eating Razor Clams
A new study shows razor clams containing low levels of domoic acid may cause memory problems for those who eat large amounts year-round.
The Department of Health recommends you eat no more than 15 razor clams each month for 12 consecutive months. This interim advisory applies to everyone, especially women who are or might become pregnant, nursing mothers, children, the elderly, and people with compromised renal function.
Why is the interim health advisory necessary?
This interim advisory is based on research from the CoASTAL study (“Community Advancing the Study of Tribal Nations Across the Lifespan”). The study was completed by the Universities of Maryland, Hawaii, and Florida, the National Oceanic and Atmospheric Administration (NOAA), and three tribes in Washington State (Quileute, Makah, and Quinault Nations). The study's goal was to determine whether exposure to low levels of domoic acid over long periods of time could affect people's health. This is the first study to evaluate long-term exposure to low levels of domoic acid from eating razor clams.
After consulting with tribal leaders, tribal advisory committee members, and medical advisors, the researchers recommended tribal members from the Quileute, Makah, and Quinault Nations eat no more than 15 razor clams each month for 12 consecutive months. The Department of Health is recommending everyone follow this advice.
What is domoic acid and how can it affect my health?
Domoic acid is a naturally occurring toxin produced by microscopic marine algae. Fish, shellfish, and crabs may eat this algae. At high levels, eating seafood with domoic acid can cause Amnesic Shellfish Poisoning. Symptoms can include nausea, vomiting, diarrhea, and abdominal cramps within 24 hours of eating contaminated seafood. In more severe cases, neurological symptoms may develop within 48 hours, including headache, dizziness, confusion, disorientation, loss of short-term memory, motor weakness, seizures, trouble breathing, irregular heartbeat, coma, and possibly death.
There is no known way to stop the harmful effects from high levels of domoic acid. The Department of Health routinely monitors shellfish for domoic acid. If levels reach or exceed 20 parts per million, we close harvesting areas to protect your health. The new CoASTAL study shows razor clams containing low levels of domoic acid may cause memory problems for those who eat large amounts year-round prompting this interim advisory.
Why is this an interim advisory?
An interim advisory is a temporary advisory put in place while health agencies gather more information. Since the focus of the CoASTAL study was on tribal members, we need more research to understand the potential exposure and health risks for others.
What are the next steps?
We plan to collaborate with researchers from the CoASTAL study to expand our knowledge. Our staff will continue to track ongoing research, and we will update this advisory as new information becomes available.
Domoic Acid in Razor Clams, Handout (PDF)