General Information

Event name: NL-89-007
Nature of the harmful event:
High Phyto concentration
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 (Phytoplankton Monitoring program. Rijkswaterstaat's North Sea Directorate.)
Event occurred before in this location: Yes (Phaeocystis occurred every year at the vertically mixed stations: The Walcheren transect, G6, the Noordwijk transect, Ts4, Ts10 and Ts235.)
Individuals to contact: WETSTEYN, L.P.M.J

Location & Date

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Location: Latitude: , Longitude:
General location information: North Sea,
HAB Area code(s): NL-01
Additional location information: Cells were found at the walcheren transect G6, the Noordwijk transect Ts4, Ts10 and Ts135.
Bloom event dates (yyyy/mm/dd): Event Date:1989-04-01
Start: 1989-04-01, End: 1989-06-15
Quarantine levels dates (yyyy/mm/dd): First detection: 1989-04-01, End: 1989-06-15
Additional date-related information: Estimated dates from April-June.


Causative organism known: Yes
Causative Species/Genus: Phaeocystis sp. (70,000,000 cells/L)
Noordwijk transect station.
Co-Ocurring Species/Genus:
Chlorophyll concentration, if known: µg/l
Additional bloom information: The highest cell numbers (>10,000,000 cells/L) always occurred during April-June. Highest cell numbers at the stations Ts4 and Ts10 were between 20-60,000,000 cells/L. At station Ts235 the highest number was 3,000,000.
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: °C, Min: °C
Salinity Range During Event:
Bloom location in the water column:
In situ
Growth Comments
Additional Environmental information: Phaeocystis occurred every year at the vertically mixed stations: The Walcheren transect, G6, the Noordwijk transect, Ts4, Ts10 and Ts235. At the Stratified stations Ts100, Ts 135 and Ts 175 Phaecystis was (almost) never found.

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: No specific economic loss. However, Phaeocsysis is put on a high interest list of the authorities. Potential effects for tourism, and aquatic life are a concern.
Management decision:
Additional harmful effect information:
Updated at 05:43 on 16 Apr 2015