Lipid and fat soluble (lipophilic) toxins linked to diarrhetic shellfish poisoning and azaspiracid shellfish poisoning are emerging threats to recreational, subsistence, and commercial shellfisheries in Washington State. These toxins are produced by blooms of the microscopic algae Dinophysis and Azadinium. This project optimizes methods for detecting lipophilic toxins and transfers detection and analytical technologies to the Washington Department of Health.
Why We Care
Until recently, diarrhetic shellfish poisoning (DSP) did not appear to be a problem in the United States. However, in 2011, three people became ill in Washington State after eating recreationally harvested mussels from Puget Sound. Laboratory analysis of contaminated shellfish from the same area, confirmed this as the first recognized DSP illnesses in the United States. Other human illnesses, such as azaspiracid shellfish poisoning (AZP), have been linked to a suite of lipophilic algal toxins. As a result of recent bloom events and human illnesses there is an urgent need to develop and transfer operational HAB cell and toxin detection methods to help Washington State health officials monitor and accurately quantify risks from lipophilic toxins.
What We Are Doing
The three-year project uses comprehensive field and laboratory studies to characterize the abundance and distribution of Dinophysis and Azadinium and their toxins in seawater and shellfish. It establishes and validates a tiered early warning system for lipophilic shellfish toxins and assists Washington State Department of Health in establishing globally accepted protocols for quantifying lipophilic toxins as an integrated part of their biotoxin-monitoring program.
In partnership with the Washington State monitoring programs SoundToxins (Puget Sound) and Olympic Region Harmful Algal Bloom (ORHAB) project (Washington Pacific coast), water is collected weekly from June to September (with higher frequency during bloom periods) from eight shore-based sites in Puget Sound and two shore-based ORHAB outer coast sites. The abundance of targeted phytoplankton species is quantified via microscopy, with species identity confirmed by quantitative PCR and scanning electron microscope. Other associated environmental parameters measured include chlorophyll a, dissolved oxygen, temperature and salinity. Toxins are analyzed in shellfish, collected in collaboration with the Washington State Department of Health, and in passive toxin sampling devices known as Solid Phase Toxin Tracking (SPATT) disks. These disks contain resins that adsorb lipophilic toxins from the water column to provide a time-averaged record of toxin concentrations. SPATT deployments occur weekly at the eight Puget Sound sites and one ocean site, with an increase to twice-weekly during bloom periods. Together, these measurements will be used to develop early warning, monitoring and analytical techniques to help Washington State manage lipophilic toxin risks.
Benefits of Our Work
Recent and unprecedented DSP outbreaks in the Pacific Northwest have highlighted human health risks posed by lipophilic toxins. However, high concentrations of Dinophysis species have been found in other regions of the U.S., including Texas, New York, and California, suggesting that DSP poses a risk to shellfish safety in other parts of the U.S.. This work addresses clear gaps in knowledge that prevents adequate management of lipophilic toxins in Washington State and address stated needs of the WDOH. This project will enable the WDOH to better assess the risks of DSP and AZP exposure and to take steps to establish a dedicated monitoring effort for these toxins. This work will also benefit state and federal shellfish managers, tribal harvesters, and commercial shellfish farmers.
Led by the NOAA Northwest Fisheries Science Center’s Marine Microbes & Toxins Program, the project team includes researchers from the NCCOS Stressor Detection & Impacts Division, Jamestown S’Klallam Tribe, University of Washington Sea Grant, Washington Department of Health, Alfred-Wegener Institute, Molecular Resources LLC, the U.S. Food and Drug Administration, SoundToxins, and ORHAB. This project is part of the NCCOS Monitoring and Event Response for Harmful Algal Blooms (MERHAB) program.