General Information

Event name: ZAF-15-001
Nature of the harmful event:
High Phyto concentration , Other ( 1st bloom event associated with anoxia and marine mortalities caused by P. triestunum.)
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: -32.728889, Longitude: 18.097778
General location information: St Helena Bay, West Coast
HAB Area code(s): ZAF-01
Additional location information: There were 22 sampling stations within the St Helena Bay area.
Bloom event dates (yyyy/mm/dd): Start: 2015-02-01, End: 2015-03-31
Quarantine levels dates (yyyy/mm/dd):
Additional date-related information: Sampling on 10 and 11 February 2015.


Causative organism known: Yes
Causative Species/Genus: Prorocentrum triestinum (14.32x10e6 cells/L)
at station 3 on 10 February 2015
Co-Ocurring Species/Genus:
Chlorophyll concentration, if known: 278.8 µg/l
Additional bloom information: Subsurface maximum chlorophyll-a was recorded at St 19.
Event-related bibliography: NDHLOVU, A., DHAR, N., GARG, N., XUMA, T., PITCHER, G.C., SYM, S.D. and P.M. DURAND 2017 Red tide forming dinoflagellate Prorocentrum triestinum: identification, phylogeny and impacts on St Helena Bay, South Africa. Phycologia, 56 (6): 649665.

Environmental Conditions

Weather: Turbidity (NTU): Wind direction:
Stratified water: Yes Oxygen content (nL/L): < 0.06 Wind velocity:
Temperature (°C): >19.3 Oxygen saturation %: Current Direction:
Sechhi disk (m): Salinity: Current Velocity:
Nutrient information:
Temperature Range During Event: Max: 22.1 °C, Min: >10 °C
Salinity Range During Event:
Bloom location in the water column: Whole column
Growth: Advected
Growth Comments
Additional Environmental information: The red tide was observed along approximately 200km of the Namaqua coastline, extending well north of the Olifants river and southwards into the Bay.

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: 415 tons of rock lobster (Jasus lalandii), 21 tons of molluscs (mostly the white mussel Donax serra) and 7 tons of various fish species.
Management decision:
Additional harmful effect information:
Created at 03:03 on 23 Apr 2018
Updated at 12:04 on 24 Apr 2018