General Information

Event name: NO-90-004
Country: NORWAY
Nature of the harmful event:
Water Discoloration
Event directly affected:
Toxicity detected: No
Associated syndrome:
Unexplained toxicity: No
Species implicated in toxin transmission (transvector):
Report the outcome of a monitoring programme: Yes
Event occurred before in this location: Yes (This phagotrophic dinoflagellate has now and then caused patches of reddish water in the Skagerrak area during summer, but this was probably the most extensive mass occurrence in recent years.)
Individuals to contact: DAHL, Einar

Location & Date

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Location: Latitude: , Longitude:
General location information: the Skagerrak area.,
HAB Area code(s): NO-11
Additional location information:
Bloom event dates (yyyy/mm/dd): Start: 1990-07-01, End: 1990-07-30
Quarantine levels dates (yyyy/mm/dd):
Additional date-related information: July


Causative organism known: Yes
Causative Species/Genus: Noctiluca miliaris ( cells/L)
Co-Ocurring Species/Genus:
Chlorophyll concentration, if known: µg/l
Additional bloom information: Noctiluca miliaris caused patches of reddish water at the surface. The width of the patches was from only 1-2 metres to sometimes several hundred, while the length was up to kilomitres. The concentration of Noctiluca the in the reddish patches was not mea
Event-related bibliography:

Environmental Conditions

Weather: Turbidity (NTU): Wind direction:
Stratified water: Yes 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: 18 °C, Min: 16 °C
Salinity Range During Event: Max: 34, Min: 24
Bloom location in the water column:
Growth: Advected
In situ
Growth Comments The most dense patches were due to physical concentration mechanisms combined with the capacity of the algae to regulate its specific weight.
Additional Environmental information: The water column was strongly stratified with only low concentrations of nutrients in the surface layer.

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: A short information on the phenomenon was given to the public through massmedia.
Additional harmful effect information: Patches of reddish sea were observed over large areas. Some small bays were temporarily unsuitable for swimming.
Updated at 02:25 on 5 Mar 2018