General Information

Event name: CA-91-006
Country: CANADA
Nature of the harmful event:
Seafood toxins
Event directly affected:
Toxicity detected: Yes (Approximate range: 18 g/g DA.)
Associated syndrome: ASP
Unexplained toxicity: No
Species implicated in toxin transmission (transvector):
Report the outcome of a monitoring programme: Yes
Event occurred before in this location: Yes (Low numbers of Nitzschia pungens but no domoic acid had previously been detected in Malpeque Bay, but this is the first year that the bay was closed to harvesting due to domoic acid contamination.)
Individuals to contact: SMITH, John C.

Location & Date

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Location: Latitude: , Longitude:
General location information: Western Prince Edward Island, Gulf Region
HAB Area code(s): CA-25
Additional location information: Malpeque and Cascumpec Bays
Bloom event dates (yyyy/mm/dd): Event Date:1991-10-31
Quarantine levels dates (yyyy/mm/dd):
Additional date-related information: Late October-early November.


Causative organism known: Yes
Causative Species/Genus: Nitzschia pungens f. multiseries (15,400 - 3 cells/L)
Depending on the station in Lennox Channel, on October 31.
Co-Ocurring Species/Genus:
Chlorophyll concentration, if known: µg/l
Additional bloom information: Cell numbers thereafter dropped to undetectable.
Event-related bibliography:

Environmental Conditions

Weather: Turbidity (NTU): Wind direction:
Stratified water: Oxygen content (nL/L): Wind velocity:
Temperature (°C): Oxygen saturation %: Current Direction:
Sechhi disk (m): Salinity: 27 Current Velocity: 0
Nutrient information:
Temperature Range During Event: Max: 16 °C, Min: 9 °C
Salinity Range During Event:
Bloom location in the water column:
In situ
Growth Comments Most probably the population originated within the bays.
Additional Environmental information: The water column was well mixed.

Toxin Assay Information

Species containing the toxin Toxin type Toxin details Max. concentration Assay type
Crassostrea virginica Domoic Acid DA eq 3 g/g LC
Mytilus edulis Domoic Acid DA eq 18 g/g LC
Kit used: Type of kit used:
Additional information: One sample of mussels (Mytilus edulis) from Lennox Island in Malpeque Bay reached 18 g/g on October 28, but this was an outlier; most of the samples contained less than 5 g/g. Cascumpec Bay mussels and oysters (Crassostrea virginica) contained less than 3 g/g.
Economic losses:
Management decision: As a precaution due to levels nearing the federal limit of 20 g/g, the following areas were closed to the harvesting of molluscan shellfish from October 31 to November 4: Lennox Channel, Darnley Basin, Malpeque Bay, Bideford River, and Conway Narrows.
Additional harmful effect information:
Updated at 07:13 on 25 Sep 2013