General Information

Event name: US-91-007
Nature of the harmful event:
Mass mortalities
Event directly affected:
Toxicity detected: No
Associated syndrome: OTHER
Unexplained toxicity: No
Species implicated in toxin transmission (transvector):
Report the outcome of a monitoring programme: Yes
Event occurred before in this location: Yes (Suspected but not documented.)
Individuals to contact: BURKHOLDER, Joann , NOGA, E.

Location & Date

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Location: Latitude: , Longitude:
General location information: Pamlico River, Taylor Creek, etc ..., North Carolina.
HAB Area code(s): US-11
Additional location information: Pamlico River (6 stations), Taylor Creek, Lee Brothers Aquaculture Aurora Facility, Nense River (2 stations). Also: NC Maritime Museum (all fish species in holding tank), Jan. 1992, and National Marine Fisheries Service, Beaufort (Menhaden tank), Feb. 1992.
Bloom event dates (yyyy/mm/dd):
Quarantine levels dates (yyyy/mm/dd):
Additional date-related information: 15 May, 4 Aug, 10 (?) Sep, 7-20 Oct, 15 Dec, 1991.


Causative organism known: Yes
Causative Species/Genus: Pfiesteria piscicida Steidinger et Burkholder 1996 ( cells/L)
Previously reported as Pfiesteria, however, Karlodinium is now believed to be the causative species
Co-Ocurring Species/Genus:
Chlorophyll concentration, if known: µg/l
Additional bloom information: Alga may be a new species within genus Alexandrium (K. Steidinger is helping to get the plate formula for formal speciation). Note-subsequently identified as Pfiesteria piscicida Quickly encysts and settles out once fish are dead. Cysts characteristics
Event-related bibliography:

Environmental Conditions

Weather: Turbidity (NTU): Wind direction:
Stratified water: Yes 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: 28 °C, Min: 12 °C
Salinity Range During Event: Max: 35,
Bloom location in the water column:
Growth Comments Describe physical location: Various tributaries and acquaculture facilities as described previously.
Additional Environmental information: Salinity range: 0/ppt (with water or high in Ca++) 35 ppt = kills as documented by Burkholder. Oxygen concentration: from low (approx 2 ppm) to approx 10 ppm. Water Column Stability: Unmixed, in shallow, turbid conditions.

Toxin Assay Information

Species containing the toxin Toxin type Toxin details Max. concentration Assay type
Kit used: Type of kit used:
Additional information: Underway with guidance/assistance from D. Baden, S. Hall. Fish kills confirmed with lab bioassays, (Burkholden) SEM.
Economic losses:
Management decision: Sampling protocol to detect and verify presence of the toxic dinoflagellate, directed by J. Burkholder and E. Noga (NCSU).
Additional harmful effect information: Water coloration: usually no change but on 2 occasions milky/pale tan.
Updated at 04:33 on 3 Apr 2019