General Information

Event name: ZAF-07-001
Country: SOUTH AFRICA
Nature of the harmful event:
High Phyto concentration
Event directly affected:
Shellfish
Toxicity detected: Yes (Approximate range: 0.5 - 11.7 mg STX eq kg-1)
Associated syndrome: PSP
Unexplained toxicity: No
Species implicated in toxin transmission (transvector):
Report the outcome of a monitoring programme: No
Event occurred before in this location:
Individuals to contact: MANSFIELD, Lisa

Location & Date

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Location: Latitude: -32.039167, Longitude: 18.260000
General location information: Lamberts Bay, West Coast
HAB Area code(s): SA-01
Additional location information: Mooring station 3.5km offshore of Lambert's Bay, within the St Helena Bay region.
Bloom event dates (yyyy/mm/dd): Start: 2007-03-20, End: 2007-04-11
Quarantine levels dates (yyyy/mm/dd):
Additional date-related information: 20 March-11 April -2 upwelling periods occur

Microalgae

Causative organism known: Yes
Causative Species/Genus: Alexandrium catenella (6.1x10e5 cells/L)
at 5m on 22 March
Co-Ocurring Species/Genus: Dinophysis acuminata (8.3x10e4 cells/L)
at 5m on 25 March
Pseudo-nitzschia spp. (1.2x10e6 cells/L)
at 5m on 29 March
Chlorophyll concentration, if known: 38 - 63 µg/l
Additional bloom information: An increase in phytoplankton biomass was associated with the onset of each period of downwelling, depicted by subsurface chlorophyll-a maxima of 38g/L (on 22 March) 63g/L (on 29 March). The extended period of stratification during the later stages of the study, from 3 to 11 April, was distinguished by low phytoplankton biomass depicted by chlorophyll-a concentrations less than 5g/L.
Event-related bibliography: HUBBART, B., PITCHER, G.C., KROCK, B. and A.D. CEMBELLA 2012 Toxigenic phytoplankton and concomitant toxicity in the mussel Choromytilus meridionalis off the west coast of South Africa. Harmful Algae, 20: 30-41.

Environmental Conditions

Weather: Turbidity (NTU): Wind direction:
Stratified water: Yes Oxygen content (nL/L): Wind velocity:
Temperature (°C): 11.5 - 16.5 Oxygen saturation %: Current Direction:
Sechhi disk (m): Salinity: Current Velocity:
Nutrient information:
Temperature Range During Event: Max: 16.5 °C, Min: 10.5 °C
Salinity Range During Event:
Bloom location in the water column:
Surface
Subsurface
Growth: Advected
Growth Comments
Additional Environmental information:

Toxin Assay Information

Species containing the toxin Toxin type Toxin details Max. concentration Assay type
Alexandrium catenella Saxitoxins STX 4.8x10e7 pgSTX eqL-1 LC-FD
Kit used: Type of kit used:
Additional information: Four different assays were carried out (LC-FD, ELISA, RBA and MBA) to test for PSP. Results and bias are compared in this study.
Economic losses:
Management decision:
Additional harmful effect information:
Created at 12:08 on 20 Apr 2018
Updated at 12:34 on 23 Apr 2018
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