Harmful Algal Information System: Event US-91-012

General Information

Event name:	US-91-012
Country:	UNITED STATES
Nature of the harmful event:	Seafood toxins
Event directly affected:
Toxicity detected:	Yes (Approximate range: 10,000 痢 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 (1927, 1929, 1932, 1954, 1962, 1963, 1964, 1965, 1966, 1970, 1971, 1976, 1980, 1981, 1982, 1984, 1986, 1988, 1989, 1990.)
Individuals to contact:	ROSS, Maria R.

Location & Date

[View larger map]

Location:	Latitude: , Longitude:
General location information:	Marin County., California. HAB Area code(s): US-21
Additional location information:	Stinson Beach/south rocks, Rodeo Beach, Kehoe Beach (Wild Sea Mussels); Drakes Bay/Chimney Rock, Tomales Bay/Lawson's Landing (Sentinel Sea Mussels); Drakes Estero/Bed#12, Tomales Bay/Lease #M430-10 (Wild Bay Mussels, Sentinel Bay Mussels); Tomales Bay/Marconi Cove and Leases #M430-10, 11, 14 (Cultured Bay Mussels); Drakes Bay/Chimney Rock LBS (Sentinel Pacific Oysters); Drakes Estero/Beds 3, 8, 12, 22, Tomales Bay/Marconi Cove, Lawson's Landing, Leases =M430-02, 02B, 10, 11, 14, HIOC Wet Storage (Cultured Pacific Oysters); Tomales Bay/Lease #M430-10, 11 (Manila Clam); Tomales Bay/Clam Island (Gaper Clam).
Bloom event dates (yyyy/mm/dd):
Quarantine levels dates (yyyy/mm/dd):
Additional date-related information:	January, February, June, July, August, September high above alert levels; March, October, November high measurable but below alert concentrations.

Microalgae

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:

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

Both advected population from the northern coastal areas and in situ growth most likely contributed to the bloom condition.

Additional Environmental information:

No data available.

Toxin Assay Information

Species containing the toxin	Toxin type	Toxin details	Max. concentration	Assay type
Sentinel sea mussel	Saxitoxins	STX eq	10,000	Bioassay-Mouse
Wild sea mussel	Saxitoxins	STX eq	1,900	Bioassay-Mouse
Wild Bay mussels	Saxitoxins	STX eq	4,100	Bioassay-Mouse
Cultured bay mussels	Saxitoxins	STX eq	2,400	Bioassay-Mouse
Gaper clam viscera	Saxitoxins	STX eq	2,500	Bioassay-Mouse
Manila clam	Saxitoxins	STX eq	110	Bioassay-Mouse
Sentinel Pacific oyster	Saxitoxins	STX eq	1,200	Bioassay-Mouse
Cultured Pacific oysters	Saxitoxins	STX eq	2,200	Bioassay-Mouse

Kit used: No

Type of kit used:

Additional information:

Economic losses:

Management decision:

The magnitude and geographical extent of the toxic Alexandrium catenella bloom resulted in the issuance of a special quarantine order by the Director of Health Services on July 25, 1991 to include all bivalve shellfish taken by sport harvesters. On July

Additional harmful effect information:

These high concentrations occurred during the months of July and August.