General Information

Event name: VE-91-001
Nature of the harmful event:
Water Discoloration , Seafood toxins
Event directly affected:
Toxicity detected: Yes
Associated syndrome: PSP
Unexplained toxicity: No
Species implicated in toxin transmission (transvector): Perna perna
Report the outcome of a monitoring programme: No
Event occurred before in this location: Yes
Individuals to contact: Lorelys Valerio

Location & Date

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Location: Latitude: , Longitude:
General location information: Margarita Island,
HAB Area code(s): VE-04
Additional location information: Manzanillo beach and Guayacan beach
Bloom event dates (yyyy/mm/dd): Event Date:1991-08-01
Start: 1991-08-28, End: 1991-10-15
Quarantine levels dates (yyyy/mm/dd): First detection: 1991-08-28, End: 1991-11-28
Additional date-related information:


Causative organism known: Yes
Causative Species/Genus: Alexandrium tamarense (Lebour) Balech 1985 (20 cell/ml. cells/L)
Co-Ocurring Species/Genus: Gymnodinium catenatum Graham 1943 ( cells/L)
Chlorophyll concentration, if known: µg/l
Additional bloom information: El análisis microscópico del agua en la proximidad de los bancos de mejillones se mostró la presencia de Gymnodinium catenatum y Alexandrium tamarense; a concentraciones de ≤ 20 células / ml. Un miembro del género Cochlodinium sp. también se detectó a muy bajas densidades. Las diatomeas más abundantes fueron: Cyclotella sp., Navicula sp., Nitzschia seriata y Rhizosolenia delicatula, mientras que los dinoflagelados más abundante fueron Ceratium furca, Dinophysis cf. acuminata, Gonyaulax polygramma, Prorocentrum gracilis y Polykrikos polikrikoides. En ambos lugares, Prorocentrum gracile fue la especie dominante, y su densidad indicó que era el principal formador de la floración.
Event-related bibliography: La Barbera-Sánchez, A., Franco Soler, J., Rojas de Astudillo, L. y Chang-Yen, I. 2004. Paralytic Shellfish Poisoning (PSP) in Margarita Island, Venezuela. Rev. Biol. Trop. 52(Suppl. 1): 89-98.

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
Additional Environmental information:

Toxin Assay Information

Species containing the toxin Toxin type Toxin details Max. concentration Assay type
Saxitoxins STX 2548 µg STX Bioassay-Mouse
Kit used: Type of kit used:
Additional information: A high liquid chromatographic (HPLC) procedure was recently used on the 1991 samples. The major toxin detected in samples of both locations was decarbamoyl saxitoxin (dcSTX), but low concentrations of saxitoxin were also found in Manzanillo samples. Gonyautoxins GTX1, GTX2 and GTX3 were detected only at Guayacán, while in both locations, decarbamoylgonyatouxin (dcGTX2,3) toxins were detected.
Economic losses:
Management decision:
Additional harmful effect information:
Created at 06:15 on 28 Oct 2015
Updated at 04:49 on 29 Oct 2015