General Information

Event name: US-01-003
Nature of the harmful event:
Water Discoloration , High Phyto concentration , Seafood toxins , Mass mortalities
Event directly affected:
Natural Fish , Birds , Aquatic Mammals , Humans
Toxicity detected: Yes (Approximate range: 33.4 g/L BREVETOXINS)
Associated syndrome: NSP , Aerosolized toxins effects
Unexplained toxicity: No
Species implicated in toxin transmission (transvector): Crassostrea virginica, the Eastern Oyster.
Report the outcome of a monitoring programme: Yes (State of Florida HAB program and federal ECOHAB: Florida program.)
Event occurred before in this location: Yes (Go to
Individuals to contact: STEIDINGER, Karen A.

Location & Date

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Location: Latitude: , Longitude:
General location information: Offshore and inshore Gulf of Mexico., Gulf of Mexico and Florida.
HAB Area code(s): US-16
Additional location information: Offshore and inshore Gulf of Mexico from Panama City Beach to the Florida Keys up to Martin County on the east coast. This red tide of 2001 was first detected off SW Florida offshore of Johns Pass (27.7267 and -82.9767) and Sarasota (27.1335 and -82.9812) in January and then periodically offshore of Sarasota until June. It reappeared inshore in August off Sarasota and has been offshore and inshore (from 25.9075, -81.7076 to 27.9775, -82.8319 to -83.3916), even down to the Florida Keys. It continues today into 2002. The SW bloom evidently was transported to the north and was first detected 20 miles off Carrabelle Florida (-84.6067) on October 15, 2001, it then moved west to Panama City Beach (-85.8189).
Bloom event dates (yyyy/mm/dd): Event Date:2001-11-19
Quarantine levels dates (yyyy/mm/dd):
Additional date-related information: Date of detection of quarantine levels: 21/08/01 for SW ; 17/10/01 for N, East Bay, Apalachicola. Final date of quarantine levels: still closed for SW. open on 14/12/01 for N, East Bay, Apalachicola. Ongoing in SW.


Causative organism known: Yes
Causative Species/Genus: Karenia brevis (105,000,00 cells/L)
Co-Ocurring Species/Genus: Karenia mikimotoi (11,200,000 cells/L)
Other Karenia appear to be in Gulf of Mexico as well.
Chlorophyll concentration, if known: Maximum of 220.72 g/L Chl off of Venice, Fl µg/l
Additional bloom information: preliminary information available at and and Foley, A., Stacy, B. A., Schueller, P., Flewelling, L. J., Schroeder, B., Minch, K., Fauquier, D. A., Foote, J. J., Manire, C., Atwood, K. E., Granholm, A. A., Landsberg, J. H., 2019. Assessing Karenia brevis red tide as a mortality factor of sea turtles in Florida. Dis. Aquat. Org. 132, 109124.
Event-related bibliography:

Environmental Conditions

Weather: Turbidity (NTU): Wind direction:
Stratified water: No Oxygen content (nL/L): Wind velocity:
Temperature (°C): 21.9717 Oxygen saturation %: Current Direction:
Sechhi disk (m): Salinity: 36.1237 Current Velocity: 0
Nutrient information: PHOSPHATE: 0.14 M
Temperature Range During Event: Max: 33 °C, Min: 13 °C
Salinity Range During Event: Max: 37, Min: 22
Bloom location in the water column: Whole column
Growth: Advected
In situ
Growth Comments Both in different areas and different times, cross shelf movement and longshore movement with winds.
Additional Environmental information: SiO4: 3.08 uM, NO3/NO2: 0.02 uM, PPO4: 0.349 uM, PO4: 0.14 uM, TDP: 0.319 uM, Dissolved N/P: 0.17 uM, c Karenia brevis count: 1,755,000/L , Sigma t: 25.0814. In addition CHN and extracted chlorophyll values are available as are weather, wind, and curr

Toxin Assay Information

Species containing the toxin Toxin type Toxin details Max. concentration Assay type
Brevetoxins 1,037 Receptor Binding
Crassostrea virginica Brevetoxins 33.4 g/L ELISA
Kit used: Type of kit used:
Additional information: Positive Mouse Bioassay of <20 MU/100 gm shellfish meats to 46.4 MU/100 gm shellfish meats. Above 20 MU/100 gm shellfish meats is the regulatory level for NSP.
Economic losses:
Management decision: Closure of shellfish harvesting areas along the coast
Additional harmful effect information: 2 adults with NSP symptoms after eating oysters illegally harvested from Closed Shellfish Area.
Updated at 06:57 on 28 Jul 2020