General Information

Event name: NO-89-004
Country: NORWAY
Nature of the harmful event:
Event directly affected:
Toxicity detected: No
Associated syndrome:
Unexplained toxicity:
Species implicated in toxin transmission (transvector):
Report the outcome of a monitoring programme: No
Event occurred before in this location: Yes (Mass occurrences of G. aureolwn have previously been recorded along the Norwegian coast in 1966, 1976, 1981, 1982 and 1985. The bloom in 1988 propagated further north along the west coast than before.)
Individuals to contact: DAHL, Einar

Location & Date

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Location: Latitude: , Longitude:
General location information: The Norwegian coast from the Swedish border to the Trondelag area at the north-west coast,
HAB Area code(s): NO-01
Additional location information:
Bloom event dates (yyyy/mm/dd):
Quarantine levels dates (yyyy/mm/dd):
Additional date-related information: The middle of August to the end of October 1989.


Causative organism known: No
Causative Species/Genus: Gyrodinium aureolum ( cells/L)
Co-Ocurring Species/Genus: Ceratium furca ( cells/L)
Brownish patches along the coast, but no severe mortalities
Chlorophyll concentration, if known: µg/l
Additional bloom information:
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: Current Velocity:
Nutrient information:
Temperature Range During Event: Max: °C, Min: °C
Salinity Range During Event:
Bloom location in the water column:
Growth Comments The most dense surface popualtions were due to on site concentration of cells by physical and migration mechanisms. Compared to previous occurrences of this alga along the Norwegian coast the bloom in 1988 was probably due to growth along the coast rathe
Additional Environmental information: The dense concentrations were mainly restricted to the upper 2-3 m. The distribution was very patchy, accumulation of cells in bays due to Wind driven surface currents. The precipitation along the coast was above the normal before and during the bloom.

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: At a few sites cages were towed a short distance out of the most dense patches of brown water.
Additional harmful effect information: Patches of brownish water were recorded all along the coast and some encaged fish exposed to such patches were killed.