General Information

Event name: US-99-011
Nature of the harmful event:
Water Discoloration , High Phyto concentration
Event directly affected:
Toxicity detected: No
Associated syndrome:
Unexplained toxicity: No
Species implicated in toxin transmission (transvector):
Report the outcome of a monitoring programme: No
Event occurred before in this location: Yes
Individuals to contact: MONCREIFF, Cynthia A.

Location & Date

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Location: Latitude: 30.259367, Longitude: -89.216950
General location information: Coastal waters of Mississippi., Gulf of Mexico, Florida.
HAB Area code(s): US-17
Additional location information: Harrison and Jackson Counties in coastal Mississippi experienced blooms of this genus during the time frame indicated; location given is location from which sample with highest cell counts was collected.
Bloom event dates (yyyy/mm/dd): Event Date:1999-10-05
Start: 1999-09-14, End: 1999-10-14
Quarantine levels dates (yyyy/mm/dd):
Additional date-related information: Highest cell count observed in Jackson County on 14/10/99.


Causative organism known: Yes
Causative Species/Genus: Prorocentrum spp. (2,000 - 18 cells/L)
Discolored water due to a Skeletonema costatum bloom; Prorocentrum species detected upon microscopic examination
Prorocentrum micans ( cells/L)
Prorocentrum scutellum ( cells/L)
Prorocentrum gracile ( cells/L)
Prorocentrum minimum ( cells/L)
Co-Ocurring Species/Genus: Skeletonema costatum ( cells/L)
Cell count estimated to be "high" (in excess of 1,000,000 cells/L) due to discoloration of water
Chlorophyll concentration, if known: Not performed. µg/l
Additional bloom information: Prorocentrum spp= P. micans, P. sutellum, P.gracile & P.minimum. A list of other genera of microalgae (predominantly diatoms) present in association with the bloom is available on request. Cysts: none observed.
Event-related bibliography: None.

Environmental Conditions

Weather: Variable. Turbidity (NTU): Wind direction: NE
Stratified water: No Oxygen content (nL/L): Wind velocity: 8-12
Temperature (°C): 24.5 Oxygen saturation %: Current Direction:
Sechhi disk (m): Salinity: 31 Current Velocity: 0
Nutrient information:
Temperature Range During Event: Max: 27 °C, Min: 24 °C
Salinity Range During Event: Max: 32, Min: 20
Bloom location in the water column: Whole column
In situ
Growth Comments Assume 'in situ' growth. Prorocentrum reported to be benthic; species observed in phytoplankton may have been displaced from bottom.
Additional Environmental information: Winds during bloom period generally E to ENE at 5-10. Subsurface / throughout water column; water depth shallow (< 2 m).

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: None reported.
Management decision: None taken.
Additional harmful effect information: None reported.