General Information

Event name: CA-91-009
Country: CANADA
Nature of the harmful event:
Seafood toxins
Event directly affected:
Toxicity detected: Yes (Approximate range: 74 - 159 µg STXeq /100g.)
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 (Alexandrium bloom is an annual event reported since 1984; PSP toxic incidents known for more than 100 years in the region.)
Individuals to contact: HUPPERTZ, Béatrice , LEVASSEUR, Maurice

Location & Date

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Location: Latitude: 48.216667, Longitude: -65.716667
General location information: St. Lawrence River, Quebec Region
HAB Area code(s): CA-08
Additional location information: South shore of the Gulf of St Lawrence (49º 13' N, 65º 43' O) and north shore of the St. Lawrence estuary (48º 08' N, 69º 42' O).
Bloom event dates (yyyy/mm/dd): Event Date:1991-07-21
Quarantine levels dates (yyyy/mm/dd):
Additional date-related information: Late July - early august.


Causative organism known: Yes
Causative Species/Genus: Alexandrium excavatum (28,278 cells/L)
Maximum concentration recorded July 21
Co-Ocurring Species/Genus:
Chlorophyll concentration, if known: µg/l
Additional bloom information: First occurence May 6, 196 cells/L observed.
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: 23 Current Velocity: 0
Nutrient information:
Temperature Range During Event: Max: 13 °C, Min: 10 °C
Salinity Range During Event:
Bloom location in the water column:
Growth: Advected
In situ
Growth Comments The Alexandrium bloom found along the northern shore of the lower St. Lawence estuary may represent an endemic population since high concnetrations of motile cells have previously been observed in the water column. In contrast, bloom along the southern sh
Additional Environmental information: Temperature range: 0-15ºC (10 - 13º C during the bloom). Salinity range: 8-30‰ ( 23 ‰ during the bloom).

Toxin Assay Information

Species containing the toxin Toxin type Toxin details Max. concentration Assay type
Mytilus edulisMitilus edulis Saxitoxins STX eq 159 Bioassay-Mouse
Mya arenaria Saxitoxins STX eq 74 Bioassay-Mouse
Kit used: Type of kit used:
Additional information: AOAC mouse bioassay.
Economic losses:
Management decision: Harvesting of shellfish periodically prohibited. Due to recurring mussel intoxications along the northern Gaspé penninsula, certain zones remained closed without PSP analysis.
Additional harmful effect information:
Updated at 07:07 on 25 Sep 2013