General Information

Event name: NZ-93-001
Nature of the harmful event:
High Phyto concentration , Seafood toxins
Event directly affected:
Toxicity detected: Yes
Associated syndrome: NSP , PSP , Aerosolized toxins effects
Unexplained toxicity:
Species implicated in toxin transmission (transvector): clams, green mussels, oysters
Report the outcome of a monitoring programme: No
Event occurred before in this location: No
Individuals to contact: Hallegraeff Gustaaf , RHODES Lesley

Location & Date

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Location: Latitude: -36.708889, Longitude: 175.987778
General location information: North Eastern, North Island
HAB Area code(s): NZ-02
Additional location information:
Bloom event dates (yyyy/mm/dd): Start: 1993-01-04,
Quarantine levels dates (yyyy/mm/dd):
Additional date-related information:


Causative organism known: Yes
Causative Species/Genus: Karenia mikimotoi (Mikaye et Kominami ex Oda) Hansen et Moestrup 2000 (180 000 cells/L)
Alexandrium minutum Halim 1960 (117 000 cells/L)
Co-Ocurring Species/Genus: Pseudo-nitzschia pungens (10 000 cells/L)
Chlorophyll concentration, if known: µg/l
Additional bloom information: During the crisis 14 toxic/potentially harmful phytoplankton species were identified
Event-related bibliography: Chang, F.H., MacKenzie, A.L., Till, D., Hannah, D. and Rhodes, L.L. (1995) The first toxic shellfish outbreaks and the associated phytoplankton blooms in early 1993 in New Zealand. In: Harmful marine algal toxins. (Lassus et al. eds. Lavoisier, Intercept Ltd.)

Environmental Conditions

Weather: El Nino phase 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
Shellfish Brevetoxins 595 MU 100 g^-1 Bioassay-Mouse
Shellfish Saxitoxins NEO Bioassay-Mouse
Kit used: No Type of kit used:
Additional information:
Economic losses: Loss in export sales was estimated to be NZ $2 million per week.
Management decision: Long term closure of entire New Zealand coastline. Implementation of a monitoring of harmful microalgae in New-Zealand in June 1993.
Additional harmful effect information: 180 people hospitalized
Created at 09:40 on 10 Jan 2018
Updated at 03:11 on 4 May 2018