General Information

Event name: ZAF-62-001
Nature of the harmful event:
Water Discoloration , High Phyto concentration , Mass mortalities , Foam/Mucilage in the coast
Event directly affected:
Planktonic life , Natural Fish , Shellfish
Toxicity detected: No
Associated syndrome: OTHER
Unexplained toxicity: No
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: -34.218056, Longitude: 18.658056
General location information: False Bay and Walker Bay, South Coast
HAB Area code(s): ZAF-02
Additional location information: Area covered by the bloom from Muizenberg in Flase Bay to Hermanus in Walker Bay
Bloom event dates (yyyy/mm/dd): Event Date:1962-03-04
Start: 1962-03-03, End: 1962-03-10
Quarantine levels dates (yyyy/mm/dd):
Additional date-related information:


Causative organism known: Yes
Causative Species/Genus: Gonyaulax polygramma Stein 1883 (10000000 cells/L)
Co-Ocurring Species/Genus: Prorocentrum micans Ehrenberg 1833 (1000000 cells/L)
ratio of 10:100 with G. polygramma
Chlorophyll concentration, if known: µg/l
Additional bloom information:
Event-related bibliography: GRINDLEY, J.R. and F.J.R. TAYLOR 1962 - Red water and marine fauna mortality near Cape Town. Trans. Roy. Soc. S. Afr. 37: 111-130 + 1 plate.

Environmental Conditions

Weather: calm Turbidity (NTU): Wind direction: N
Stratified water: Yes Oxygen content (nL/L): Wind velocity:
Temperature (°C): 13.8-17.0 Oxygen saturation %: Current Direction:
Sechhi disk (m): Salinity: 34.83 to 35.00 Current Velocity:
Nutrient information:
Temperature Range During Event: Max: 21.1 °C, Min: 11.0 °C
Salinity Range During Event:
Bloom location in the water column:
Growth Comments
Additional Environmental information: The fish killed were almost all inshore-reef and shallow-water fish. Large numbers of dead invertebrates only started to appear a few days after the start of the fish mortality.

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: Over 100 tons of dead fish and invertebrates were removed from 4 miles of coast from Gordon's Bay and Strand.
Management decision:
Additional harmful effect information: The sea in the Strand-Gordons Bay area became slimy with rotting plankton and the water produced an almost unbearable stench that was detectable in the centre of Cape Town 30 miles away.
Created at 04:25 on 19 Jun 2018
Updated at 04:46 on 19 Jun 2018