Sampling is underway as the University of Washington Tacoma, Washington Department of Health, and the Washington Department of Fish and Wildlife work to map overwintering harmful algal cysts in Willapa Bay and Grays Harbor, Washington in partnership with NOAA’s National Centers for Coastal Ocean Science (NCCOS) Harmful Algal Bloom (HAB) Event Response Program. The resulting cyst map data will help state shellfish managers and growers predict potential blooms this spring and summer, and mitigate their harmful impacts on the region.
In May and June of 2024, Washington and Oregon experienced an extreme paralytic shellfish poisoning (PSP) event along their coastal beaches and bays, prompting response assistance from NCCOS. This PSP event marks the first documented outbreak causing widespread shellfish closures along Washington and Oregon’s coasts since the 1990s. Over 40 individuals in Oregon were confirmed to have PSP, some requiring hospitalization. Recreational and commercial shellfisheries in both states had to be closed due to high levels of PSP toxins, including in Washington’s Grays Harbor and Willapa Bay. In Willapa Bay, emergency shellfish recalls and closures led to over $900,000 in losses for the commercial shellfish industry, leading to additional hardships for rural Washington communities.
PSP is caused by neurotoxins (like saxitoxin) produced by certain species of harmful algae, including Alexandrium catenella. During an Alexandrium bloom, shellfish can accumulate dangerous concentrations of PSP toxins in their tissues. These PSP toxins can not be destroyed by freezing or cooking shellfish. Consuming toxic shellfish can cause PSP in humans and other animals, including marine mammals and birds. Symptoms of PSP in humans can include numbness or tingling of the mouth and lips, nausea, vomiting, diarrhea, cardiac and respiratory failure. Shellfish are regularly monitored for HAB toxins, and harvests are closed when toxins exceed regulatory limits.
Alexandrium forms dormant cysts that overwinter on the seafloor. If conditions are right the following summer, the cysts (like seeds) germinate, swim to the surface and multiply, potentially forming another bloom. Maps of cyst abundance combined with other contextual data can help inform our understanding of where future toxic Alexandrium blooms and PSP outbreaks could occur.
This NCCOS-supported HAB Event Response project will provide the first Alexandrium cyst maps of southern Washington’s Willapa Bay and Grays Harbor, providing critical information for contingency planning for state agencies and shellfish growers.
The NCCOS HAB Event Response Program is a national program authorized by the Harmful Algal Bloom and Hypoxia Research and Control Act (HABHRCA) that provides immediate support to help state, tribal, and local officials manage events and advance the understanding of HABs as they occur. For more information about the NCCOS HAB Event Response Program, contact us at nccos.hab.event.response@noaa.gov.
Partner Links:
- University of Washington – Tacoma
- Washington Department of Health – Shellfish Program
- Washington Department of Fish and Wildlife
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