General Information

Event name: US-22-013
Nature of the harmful event:
High Phyto concentration , Seafood toxins
Event directly affected:
Shellfish , Humans
Toxicity detected: Yes (Approximate range: 106-991 μg/100 g shellfish tissue)
Associated syndrome: PSP
Unexplained toxicity: No
Species implicated in toxin transmission (transvector): Case consumed multiple meals of contaminated butter clams recreationally harvested from a closed area over a period of a few days. Others known to case consumed clams with no symptoms. Case complained of tingling/numbness the next morning.
Report the outcome of a monitoring programme: Yes (Marine Biotoxin Program at the Washington State Department of Health, Office of Environmental and Health and Safety.)
Event occurred before in this location: Yes
Individuals to contact: BORCHERT, Jerry , BARRY, Tracie

Location & Date

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Location: Latitude: , Longitude:
General location information: Washington State, Central Puget Sound,
HAB Area code(s): US-24
Additional location information: PSP closures occurred later than usual beginning in mid September lasting through November. No PSP new PSP closures occurred in the Whidbey Basin in 2022, but butter/varnish clam closures remain in place due to elevated PSP levels.
Bloom event dates (yyyy/mm/dd):
Quarantine levels dates (yyyy/mm/dd):
Additional date-related information:


Causative organism known: Yes
Causative Species/Genus: Alexandrium spp. ( cells/L)
Co-Ocurring Species/Genus:
Chlorophyll concentration, if known: µg/l
Additional bloom information:
Event-related bibliography:

Environmental Conditions

Weather: Turbidity (NTU): Wind direction:
Stratified water: Oxygen content (nL/L): Wind velocity:
Temperature (°C): Oxygen saturation %: Current Direction:
Sechhi disk (m): Salinity: Current Velocity:
Nutrient information:
Temperature Range During Event: Max: °C, Min: °C
Salinity Range During Event:
Bloom location in the water column:
Growth Comments
Additional Environmental information:

Toxin Assay Information

Species containing the toxin Toxin type Toxin details Max. concentration Assay type
Blue Mussels Saxitoxins 991 g/100g tissue Bioassay-Mouse
Butter Clams Saxitoxins 667g/100g Bioassay-Mouse
Pacific Oysters Saxitoxins 329g/100g Bioassay-Mouse
Varnish Clams Saxitoxins 106g/100g Bioassay-Mouse
Kit used: No Type of kit used:
Additional information:
Economic losses: Recreational, commercial and tribal ceremonial shellfish harvests were interrupted, causing cultural and economic loss to Central Puget Sound Washington communities
Management decision: WADOH closed shellfish harvesting at impacted areas to protect public health.
Additional harmful effect information: First PSP related human illness reported since 2012.
Created at 06:48 on 5 Apr 2023