General Information

Event name: US-96-010
Nature of the harmful event:
Seafood toxins
Event directly affected:
Toxicity detected: Yes (Approximate range: 160 g STXeq / 100 g.)
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 (Alert levels of PSP toxicity routinely occur in this region each year.)
Individuals to contact: LANGLOIS, Gregg

Location & Date

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Location: Latitude: , Longitude:
General location information: Drakes Estero., California.
HAB Area code(s): US-21
Additional location information: Area 21, Drakes Estero, Marin County (50 miles north of San Francisco). This is the most productive commercial shellfish growing area in California at present. Only oysters are grown and harvested for human consumption. Mussels are used as a monitoring tool. Affected Species: bay mussels (Mytilus edulis).
Bloom event dates (yyyy/mm/dd): Start: 1996-05-22, End: 1996-05-24
Quarantine levels dates (yyyy/mm/dd):
Additional date-related information:


Causative organism known: Yes
Causative Species/Genus: Alexandrium catenella ( cells/L)
Confirmed by routine phytoplankton monitoring.
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: 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 May: Unknown. Warming tredn did not last beyond a cople days. Imagery shows no clear sign of advection. Toxicity due to 'in situ' population that experiences a small increase due to warming conditions? July: advection more plausible due to appearance of
Additional Environmental information: Each event occurred during a slight warmin trend which broke down quickly. The July warming trend appeared to be better developed. Imagery poor.

Toxin Assay Information

Species containing the toxin Toxin type Toxin details Max. concentration Assay type
Mytilus edulis Saxitoxins STX eq 160 Bioassay-Mouse
Kit used: No Type of kit used:
Additional information:
Economic losses:
Management decision: Outer Estero closed to harvesting. Inner Estero placed on batch release.
Additional harmful effect information: Relatively minor episodes, each short lived.