General Information

Event name: US-95-009
Nature of the harmful event:
Seafood toxins
Event directly affected:
Toxicity detected: Yes (Approximate range: 700 g STXeq / 100 gr.)
Associated syndrome: PSP
Unexplained toxicity: No
Species implicated in toxin transmission (transvector):
Report the outcome of a monitoring programme: Yes
Event occurred before in this location: Yes (1927, '29, '32, '54, '62-'66, '70, '71, '76, '80-'84, '86-'95.)
Individuals to contact: ROSS, Maria R.

Location & Date

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Location: Latitude: , Longitude:
General location information: Marin County., California.
HAB Area code(s): US-21
Additional location information: Drakes Bay, Chimney Rock, Kehoe Beach, Rodeo Beach, Drakes Esteron, Muir Beach, Tomales Bay.
Bloom event dates (yyyy/mm/dd):
Quarantine levels dates (yyyy/mm/dd):
Additional date-related information: April-May, July- December.


Causative organism known: Yes
Causative Species/Genus: Alexandrium catenella ( cells/L)
Co-Ocurring Species/Genus:
Chlorophyll concentration, if known: µg/l
Additional bloom information:
Event-related bibliography: Ref: State of California Department of Health Services (SCDHS). Shellfish Monitoring Program Technical Reports 95-05 thru -10, -15 thru -20, -22, -23, -25 thru -28, -30 thru -33.

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: Advected
In situ
Growth Comments Although difficult to assess it is probable that both in situ and advected populations contributed to the high phytoplankton population.
Additional Environmental information: No data available.

Toxin Assay Information

Species containing the toxin Toxin type Toxin details Max. concentration Assay type
Mussel Saxitoxins STX eq 700 Bioassay-Mouse
Kit used: No Type of kit used:
Additional information: Low but detectable levels of PSP toxin in sentinel mussel tissue during April, May, Sept. thru Dec. In July toxin levels at Chimney Rock, Drakes Bay increased to 700 g, at Drakes Estero PSP concentration was 420 g, in Tomales Bay 130 g, and Rodeo Beach mussel samples assayed at 240 g/100 g tissue.
Economic losses:
Management decision: The annual quarantine on sport harversting of mussels was put in effect on May 1, 1995 and continued until October 31, 1995.
Additional harmful effect information: