General Information

Event name: NL-89-008
Nature of the harmful event:
Seafood toxins
Event directly affected:
Toxicity detected: Yes (Approximate range: Positive rat bioassay)
Associated syndrome: DSP
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 (1976, 1979, 1981, 1986)
Individuals to contact: WETSTEYN, L.P.M.J , POELMAN, Marnix

Location & Date

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Location: Latitude: 53.327778, Longitude: 5.234444
General location information: Wadden Sea,
HAB Area code(s): NL-01
Additional location information: Stations W30, W420, W590, E250.
Bloom event dates (yyyy/mm/dd): Event Date:1989-10-01
Start: 1989-09-01, End: 1989-10-30
Quarantine levels dates (yyyy/mm/dd): First detection: 1989-10-01, End: 1989-11-01
Additional date-related information: After October gradual decrease of toxicity.


Causative organism known: Yes
Causative Species/Genus: Dinophysis rotundata (10 - 180 cells/L)
Station E250
Dinophysis rotundata (1100 cells/L)
Station W590
Dinophysis rotundata (10 cells/L)
Station W420
Dinophysis rotundata (10 - 200 cells/L)
Station W30
Dinophysis acuminata (100 cells/L)
water samples from sept - October
Dinophysis acuminata (60 cells/L)
nethauls 60 liters
Co-Ocurring Species/Genus:
Chlorophyll concentration, if known: µg/l
Additional bloom information:
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: Whole column
Growth: Advected
Growth Comments
Additional Environmental information:

Toxin Assay Information

Species containing the toxin Toxin type Toxin details Max. concentration Assay type
Mussel Okadaic Acid OA Positive Bioassay-Rat
Mussels Okadaic Acid DTX1 Positive Bioassay-Mouse
Kit used: No Type of kit used:
Additional information: Bioassay-Rat.
Economic losses: Closure of the area for shellfish fisheries. Production continued in Oosterschelde.
Management decision: Although the toxicity measured by the rat bioassays was low, closure of mussel production in the western Wadden sea during October-November was necessary.
Additional harmful effect information: In 1989 DSP was measured in samples from the western Wadden sea.
Updated at 05:22 on 16 Apr 2015