General Information

Event name: US-22-012
Nature of the harmful event:
High Phyto concentration , Seafood toxins
Event directly affected:
Shellfish , Humans
Toxicity detected: Yes (Approximate range: 40-401 g/100 g)
Associated syndrome: PSP
Unexplained toxicity: No
Species implicated in toxin transmission (transvector): California Mussels, Pacific Oysters, and Rock Scallop viscera
Report the outcome of a monitoring programme: Yes (California Department of Public Health - Marine Biotoxin Monitoring Program)
Event occurred before in this location: Yes
Individuals to contact: ZUBKOUSKY-WHITE, Vanessa

Location & Date

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Location: Latitude: , Longitude:
General location information: California - Del Norte, Humboldt, Mendocino, Sonoma, and Marin, San Mateo, Santa Cruz, Monterey Counties,
HAB Area code(s): US-21
Additional location information: Locations with >80 g/100 g detected in mussels: Humboldt County - Humboldt Bay, San Mateo County - Bean Hollow State Beach, Monterey County - Monterey Wharf
Bloom event dates (yyyy/mm/dd): Event Date:2022-08-30
Quarantine levels dates (yyyy/mm/dd): End: 2022-12-05
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
California Mussels Saxitoxins 401 micrograms/gram Bioassay-Mouse
Pacific Oysters Saxitoxins 40 g/100g Bioassay-Mouse
Rock Scallop viscera Saxitoxins 72 g/100g Bioassay-Mouse
Kit used: Yes Type of kit used: NeoGen
Additional information: Shellfish homogenates are received on ice, extracted, and a Neogen rapid test determines whether the mussel sample is positive or negative. Mussel samples that are positive on NeoGen are then tested using a mouse bioassay to determine concentration of PSP toxins. All other species are only tested with mouse bioassay.
Economic losses: Commercial areas in Humboldt and Tomales Bay went under biotoxin closures or biotoxin harvest restrictions and had more frequent testing. Recreational advisories were placed on all 3 counties at different times, mussel quarantine was not in effect so pote
Management decision: Precautionary biotoxin closures were placed on growing areas initially, but they were allowed to remain open if twice weekly testing from growing area product showed results lower than 80g/100g. Recreational advisory was in place in all three counties, f
Additional harmful effect information:
Created at 06:30 on 5 Apr 2023