General Information

Event name: ZAF-97-002
Nature of the harmful event:
Water Discoloration , High Phyto concentration
Event directly affected:
Toxicity detected: No
Associated syndrome: OTHER
Unexplained toxicity:
Species implicated in toxin transmission (transvector):
Report the outcome of a monitoring programme: No
Event occurred before in this location: No
Individuals to contact: MANSFIELD, Lisa

Location & Date

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Location: Latitude: -33.007500, Longitude: 18.004722
General location information: Saldanha Bay, West Coast
HAB Area code(s): ZAF-01
Additional location information: Occurred in a tidal dam, the site of and oyster farm
Bloom event dates (yyyy/mm/dd): Event Date:1997-02-01
Start: 1997-02-01, End: 1997-03-31
Quarantine levels dates (yyyy/mm/dd):
Additional date-related information: Actual dates of the bloom were not published


Causative organism known: Yes
Causative Species/Genus: Aureococcus anophagefferens (1-3x10e9 cells/L)
Co-Ocurring Species/Genus:
Chlorophyll concentration, if known: 21-41 µg/l
Additional bloom information: First occurrence of brown tide organism, Aureococcus anophagefferens.
Event-related bibliography: PROBYN, T.A., G.C. PITCHER, R.N. PIENAAR and R. NUZZI 2001 Brown tides and mariculture in Saldanha Bay, South Africa. Mar. Poll. Bull. 42(5): 405-408.

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: Whole column
Growth Comments
Additional Environmental information: the morphology of the bay and the nature of exchange with coastal waters do provide a favourable environment for Aureococcus blooms under certain conditions.

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: Following the appearance of Aureococcus in 1997, harvests of oysters declined considerably (from approx. >50000 to <10000 oysters per month).The bay-wide bloom in 1998 also had a negative effect on mussel farmers in Small Bay.
Management decision: As a direct result of the brown tide related fall in oyster production the farm was placed in preliminary liquidation in April 1999.
Additional harmful effect information: Should bay-wide blooms of Aureococcus become a more frequent, albeit seasonal, feature of the system, they could have dire consequences for the shellfish industry in this important mariculture development area.
Created at 11:14 on 18 Jun 2018
Updated at 01:34 on 19 Jun 2018