General Information

Event name: US-90-004
Nature of the harmful event:
Seafood toxins
Event directly affected:
Toxicity detected: Yes
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 (Annual event in most years since 1972, ususally in May/June.)
Individuals to contact: ANDERSON, Donald M.

Location & Date

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Location: Latitude: , Longitude:
General location information: Massachusetts Bay, North Shore
HAB Area code(s): US-04
Additional location information:
Bloom event dates (yyyy/mm/dd): Start: 1990-05-15, End: 1990-07-15
Quarantine levels dates (yyyy/mm/dd):
Additional date-related information: Last 2 weeks of May through mid-July


Causative organism known: Yes
Causative Species/Genus: Alexandrium fundyense ( cells/L)
Alexandrium tamarense ( cells/L)
Co-Ocurring Species/Genus:
Chlorophyll concentration, if known: µg/l
Additional bloom information: Alexandrium fundyense and/or A. tamarense (variety not determined). Cell numbers 500-2500 cells/liter.
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: 11 °C, Min: 8 °C
Salinity Range During Event: Max: 31, Min: 29
Bloom location in the water column:
Growth: Advected
Growth Comments Advection from the North is the most likely cause of toxicity. Population originated near Kennebec River in Maine during early April. Growth probably also occurred during transit to the South.
Additional Environmental information: Salinity front along coast (29-31) caused by freshwater plume from further North (i.e., Merrimac and Kennebec Rivers. Slightly stratified due to buoyant plume; waters 1-2 C warmer and 2 less saline than surrounding ambient waters.

Toxin Assay Information

Species containing the toxin Toxin type Toxin details Max. concentration Assay type
Kit used: Type of kit used:
Additional information:
Economic losses:
Management decision: Mytilus edulis, Mya arenarai and other species closed to shellfishing from late May to mid-August.
Additional harmful effect information: Shellfish closures Toxic level 200-300 g/100 g shellfish (mouse bioassay: MA Division of Marine Fisheries) No human deaths or illnesses known.
Updated at 11:04 on 22 Apr 2020