General Information

Event name: US-04-004
Nature of the harmful event:
High Phyto concentration , Seafood toxins
Event directly affected:
Toxicity detected: Yes (Approximate range: 81 - 1602 g/100 g tissue)
Associated syndrome: PSP
Unexplained toxicity: No
Species implicated in toxin transmission (transvector):
Report the outcome of a monitoring programme: Yes (California Department of Health Services Marine Biotoxin Monitoring Program)
Event occurred before in this location: Yes (The length of time (months) associated with low level toxicity was unusual)
Individuals to contact: LANGLOIS, Gregg

Location & Date

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Location: Latitude: , Longitude:
General location information: Central Coast, California
HAB Area code(s): US-20 US-21
Additional location information: 1. San Luis Obispo County (20): North of Pt. Conception, encompasses Pismo Beach northward to Morro Bay and San Simeon.2. Santa Cruz County (21): North of Monterey, includes shoreline in Monterey Bay and open coast.3. Marin County (21): North of Golden Gate (San Francisco).
Bloom event dates (yyyy/mm/dd):
Quarantine levels dates (yyyy/mm/dd):
Additional date-related information: March-July 1. San Luis Obispo County: Low level PSP toxicity Jan - March. Alert level exceeded late March (535 ug), declining below alert level by early April and below detection limit by late April. Low level toxicity returned mid-October, increased above alert level early December (248 ug) through late December (94 ug).2. Santa Cruz County: Low level PSP toxicity in early June, exceeding alert level by mid-July. Max concentration by late July (770 ug), declining below detection limit by mid-August.3. Marin County: Low level PSP toxicity in early June, exceeding alert level by June 30 (129 ug). Peak concentration (1602 ug) reached by July 7, declining below alert level by mid-July. Low levels persisted through December.


Causative organism known: Yes
Causative Species/Genus: Alexandrium spp. ( cells/L)
Co-Ocurring Species/Genus:
Chlorophyll concentration, if known: µg/l
Additional bloom information: 1. San Luis Obispo County: Highest relative abundance of Alexandrium observed by volunteer network in mid-March and mid-December, associated with increasing/peak toxicity.2. Santa Cruz County: Highest relative abundance of Alexandrium observed in mid to l
Event-related bibliography: Monthly/Annual reports issued by CDHS Marine Biotoxin Monitoring Program

Environmental Conditions

Weather: Turbidity (NTU): Wind direction:
Stratified water: No Oxygen content (nL/L): Wind velocity:
Temperature (°C): Oxygen saturation %: Current Direction:
Sechhi disk (m): Salinity: Current Velocity: 0
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
Mytilus californianus Saxitoxins STX eq 770 Bioassay-Mouse
Mytilus galloprovincialis Saxitoxins STX eq 1602 Bioassay-Mouse
Crassostrea gigas Saxitoxins STX eq 420 Bioassay-Mouse
Kit used: No Type of kit used:
Additional information: Jellet/AOAC for screening in lab
Economic losses:
Management decision: Harvest closures in commercial aquaculture areas; annual quarantine on sport-harvested mussels.
Additional harmful effect information: Toxin levels detected in shellfish, primarily mussels