[MARMAM] New paper - Three brevetoxin-associated dolphin mortality events in Florida panhandle

Spencer Fire spencer.fire at noaa.gov
Thu Aug 16 12:49:16 PDT 2012

On behalf of my co-authors, I am pleased to announce the publication of the
following article:

Twiner MJ, Flewelling LJ, Fire SE, Bowen-Stevens SR, Gaydos JK, Johnson CK,
Landsberg JH, Leighfield TA, Mase-Guthrie B, Schwacke L, Van Dolah FM, Wang
Z, Rowles TK (2012).  Comparative analysis of three brevetoxin-associated
bottlenose dolphin (*Tursiops truncatus*) mortality events in the Florida
Panhandle region (USA). PLoS ONE 7: e42974

In the Florida Panhandle region, bottlenose dolphins (*Tursiops truncatus*)
have been highly susceptible to large-scale unusual mortality events (UMEs)
that may have been the result of exposure to blooms of the
dinoflagellate *Karenia
brevis* and its neurotoxin, brevetoxin (PbTx). Between 1999 and 2006, three
bottlenose dolphin UMEs occurred in the Florida Panhandle region. The
primary objective of this study was to determine if these mortality events
were due to brevetoxicosis. Analysis of over 850 samples from 105
bottlenose dolphins and associated prey items were analyzed for algal
toxins and have provided details on tissue distribution, pathways of
trophic transfer, and spatial-temporal trends for each mortality event. In
1999/2000, 152 dolphins died following extensive* K. brevis* blooms and
brevetoxin was detected in 52% of animals tested at concentrations up to
500 ng/g. In 2004, 105 bottlenose dolphins died in the absence of an
identifiable *K. brevis* bloom; however, 100% of the tested animals were
positive for brevetoxin at concentrations up to 29,126 ng/mL. Dolphin
stomach contents frequently consisted of brevetoxin-contaminated menhaden.
In addition, another potentially toxigenic algal species, *Pseudo-nitzschia*,
was present and low levels of the neurotoxin domoic acid (DA) were detected
in nearly all tested animals (89%). In 2005/2006, 90 bottlenose dolphins
died that were initially coincident with high densities of* K. brevis*.
Most (93%) of the tested animals were positive for brevetoxin at
concentrations up to 2,724 ng/mL. No DA was detected in these animals
despite the presence of an intense DA-producing *Pseudo-nitzschia* bloom.
In contrast to the absence or very low levels of brevetoxins measured in
live dolphins, and those stranding in the absence of a* K. brevis* bloom,
these data, taken together with the absence of any other obvious pathology,
provide strong evidence that brevetoxin was the causative agent involved in
these bottlenose dolphin mortality events.

The full text and pdf are available from:

Best regards,

-Spencer Fire


Spencer E. Fire, Ph.D.
Marine Biotoxins Program <http://www.chbr.noaa.gov/habar/eroart.aspx>
Center for Coastal Environmental Health and Biomolecular Research
NOAA/National Ocean Service
219 Fort Johnson Road
Charleston, SC 29412****

Tel:  843.762.8574
Fax:  843.762.8700
Email:  spencer.fire at noaa.gov
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