General Information

Event name: NL-21-001
Nature of the harmful event:
Seafood toxins
Event directly affected:
Toxicity detected: Yes (Approximate range: 353)
Associated syndrome: OTHER
Unexplained toxicity: No
Species implicated in toxin transmission (transvector):
Report the outcome of a monitoring programme: Yes (Sanitair program government)
Event occurred before in this location: Yes (2020 first time)
Individuals to contact: POELMAN, Marnix

Location & Date

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Location: Latitude: 51.742222, Longitude: 3.981667
General location information: Lake Grevelingen,
HAB Area code(s): NL-03
Additional location information:
Bloom event dates (yyyy/mm/dd): Event Date:2021-06-21
Start: 2021-06-12, End: 2021-07-07
Quarantine levels dates (yyyy/mm/dd): First detection: 2021-06-21, End: 2021-07-09
Additional date-related information:


Causative organism known: No
Causative Species/Genus:
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: Oxygen content (nL/L): Wind velocity: 5
Temperature (°C): 18.4 Oxygen saturation %: Current Direction: NE
Sechhi disk (m): Salinity: 27 Current Velocity: n.a.
Nutrient information:
Temperature Range During Event: Max: °C, Min: °C
Salinity Range During Event:
Bloom location in the water column: Whole column
In situ
Growth Comments
Additional Environmental information:

Toxin Assay Information

Species containing the toxin Toxin type Toxin details Max. concentration Assay type
Vector organism not yet known Tetrodotoxins TTX 353 LC-MS
Kit used: No Type of kit used:
Additional information: Samples were analyzed using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS)
Economic losses: Closure during off season (reproduction) for oysters
Management decision: Closure for fisheries based on the Dutch threshold 44 ug TTX / kg
Additional harmful effect information: The source is not yet known. Examination is done based on Okabe, 2021.
Created at 10:32 on 16 Jun 2022
Updated at 10:36 on 16 Jun 2022