General Information

Event name: NA-50-001
Country: NAMIBIA
Nature of the harmful event:
Water Discoloration , High Phyto concentration
Event directly affected:
Natural Fish
Toxicity detected: No
Associated syndrome:
Unexplained toxicity:
Species implicated in toxin transmission (transvector):
Report the outcome of a monitoring programme: No
Event occurred before in this location: Yes (Fish mortalities were recorded from the 1940's)
Individuals to contact: MANSFIELD, Lisa

Location & Date

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Location: Latitude: -22.886389, Longitude: 14.486667
General location information: Walvis Bay, Namibia, Northern Benguela
HAB Area code(s): NAM-01
Additional location information:
Bloom event dates (yyyy/mm/dd): Event Date:1950-12-24
Quarantine levels dates (yyyy/mm/dd):
Additional date-related information:


Causative organism known: Yes
Causative Species/Genus: Gymnodinium galatheanum Braarud 1957 ( cells/L)
Co-Ocurring Species/Genus:
Chlorophyll concentration, if known: µg/l
Additional bloom information:
Event-related bibliography: BRAARUD, T. 1957 - A red water organism from Walvis Bay (Gymnodinium galatheanum n. sp.). Galathea Deep Sea Exped. 1: 137-138. COPENHAGEN, W.J., 1953. The periodic mortality of fish in the Walvis region; a phenomenon within the Benguela Current. Investl Rep. Div. Fish. S. Afr. 14, 1-35.

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
Kit used: Type of kit used:
Additional information:
Economic losses: Thousands of tons of dead and dying fish were observed at sea or washed up on beaches in the Walvis Bay region
Management decision:
Additional harmful effect information: Cephalopods, lamellibranchs and other forms of marine life have been observed in the sea and and on the beaches of Spencer Bay, Conception Bay, Walvis Bay, Swakopmund and even as far north as the Ogab River.
Created at 07:54 on 25 Aug 2020
Updated at 07:59 on 25 Aug 2020