General Information

Event name: US-94-012
Nature of the harmful event:
Water Discoloration
Event directly affected:
Toxicity detected: No
Associated syndrome:
Unexplained toxicity: No
Species implicated in toxin transmission (transvector):
Report the outcome of a monitoring programme: Yes
Event occurred before in this location: No
Individuals to contact: DORTCH, Quay

Location & Date

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Location: Latitude: , Longitude:
General location information: , Lousiana.
HAB Area code(s): US-17
Additional location information: Louisiana continental shelf from barrier islands to at least 20 miles offshore south of Terrebonne Bay.
Bloom event dates (yyyy/mm/dd): Event Date:1994-03-07
Quarantine levels dates (yyyy/mm/dd):
Additional date-related information: 7 March (star of bloom unknown).


Causative organism known: Yes
Causative Species/Genus: Heterosigma sp. (10,000 cells/L)
Heterosigma cf. Akashiwo. Nearest shore.
Heterosigma sp. (5,000,000 cells/L)
Heterosigma cf. Akashiwo. Offshore.
Co-Ocurring Species/Genus:
Chlorophyll concentration, if known: µg/l
Additional bloom information: Surface water samples. This species was observed earlier at low levels in Terrebonne Bay estuary, along with possible benthic palmelloid stage.
Event-related bibliography:

Environmental Conditions

Weather: Turbidity (NTU): Wind direction:
Stratified water: No Oxygen content (nL/L): Wind velocity:
Temperature (°C): Oxygen saturation %: Current Direction:
Sechhi disk (m): Salinity: Current Velocity: 0
Nutrient information:
Temperature Range During Event: Max: 19 °C, Min: 17 °C
Salinity Range During Event: Max: 29, Min: 21
Bloom location in the water column:
Growth Comments Not known.
Additional Environmental information: Bloom dispersed by severe storm and not seen again that year, obviating need for over flights.

Toxin Assay Information

Species containing the toxin Toxin type Toxin details Max. concentration Assay type
Kit used: No Type of kit used:
Additional information:
Economic losses:
Management decision: None (over flights planned before bloom dispersed by strom).
Additional harmful effect information: Effect: Water discoloration.