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Shellfish Safety


Important:  Before harvesting or consuming local, recreationally-harvested shellfish, always check the status of shellfish harvesting first. Marine biotoxins can become concentrated in shellfish to dangerous levels that makes them unsafe to eat. Shellfish with toxic levels of biotoxins don’t look or taste different, so be sure to check first! Shellfish harvested commercially that are available in stores and restaurants are tested for toxins before distribution, and are safe to eat.


Vibriosis in Shellfish:

Vibriosis is an intestinal disease caused by bacteria called vibrio. Vibrio are found naturally in marine coastal waters and areas where freshwater meets saltwater (some rivers and streams). Vibrio are also found in fish and shellfish living in these waters. This bacterium usually occurs in low numbers and is not harmful. However, warm weather can cause levels of vibrio to grow. Consuming raw or undercooked fish or shellfish contaminated with high levels of vibrio can cause illness, including diarrhea, abdominal cramps, nausea, vomiting, headache, fever, and chills. Because vibrio multiplies in warm weather, the Washington State Department of Health advises that all shellfish recreationally harvested June-September should be thoroughly cooked to avoid illness due to Vibriosis. Here are a few steps you can take to reduce your risk of sickness from Vibriosis:

  • Eat only well cooked shellfish, especially during the summer months when vibrio levels tend to be higher.
  • For more information on Vibriosis, visit the Washington State Department of Health Website

When Harvesting:

  • Before harvesting, review the Washington State Department of Health shellfish safety map for closures. You can also call Mason County Public Health and Human Services at 360-427-9670 ext. 400 or the Marine Biotoxin Hotline at 1-800-562-5632.
  • Don’t harvest shellfish if they have been exposed to the sun for more than one hour.
  • Keep shellfish cold after harvesting.

Paralytic Shellfish Poisoning (PSP):

Paralytic shellfish poison is a naturally occurring toxin called biotoxin and is produced by some species of algae. PSP can become concentrated in shellfish and cause illness in people if these contaminated shellfish are eaten. This biotoxin quickly affects the nervous system and can cause tingling in the lips and tongue, hands and feet, and even cause difficulty in breathing. Anyone experiencing these symptoms should contact a health care provider immediately. For extreme reactions, call 911.
All molluscan shellfish (those having a hinged shell) are capable of building up high concentrations of PSP. This includes clams, mussels, oysters, geoduck and scallops. Crab feed on other shellfish, so PSP can accumulate in crab gut as well (although it’s not known to accumulate in crab meat). Here are a few steps you can take to help stay safe and healthy while enjoying some of the great natural resources that Mason County has to offer:

  • Clean crab thoroughly before cooking and discard “crab butter.”
  • Shellfish are regularly tested for PSP and areas with unsafe levels of the toxin are closed. Before harvesting or consuming any local, recreationally-harvested shellfish, review the Washington State Department of Health shellfish safety map or call the Marine Biotoxin Hotline at 1-800-562-5632.
  • For more information on PSP, visit the Washington State Department of Health website.
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