[MARMAM] New publication: - Red tide exposure and corresponding neurotoxins in Texas dolphins

Spencer Fire sfire at fit.edu
Fri Oct 16 08:27:35 PDT 2020

Dearest MARMAM-ers,
My collaborators and I are pleased to announce the publication of our recent article, "Association between red tide exposure and detection of corresponding neurotoxins in bottlenose dolphins from Texas waters during 2007-2017", in Marine Environmental Research.

Harmful algal blooms produced by the phytoplankton species Karenia brevis and its associated neurotoxin, brevetoxin (PbTx), occur throughout the Gulf of Mexico and have had devastating impacts on co-occurring populations of bottlenose dolphins (Tursiops truncatus), an important marine sentinel species. The majority of documented impacts, however, are from the eastern Gulf of Mexico, with a critical lack of information on the degree and frequency of PbTx exposure in bottlenose dolphins from Texas coastal waters. This study documents PbTx exposure in Texas bottlenose dolphins between 2007 and 2017 and their association with co-occurring K. brevis blooms. PbTx was detected in 60% (n = 112) of the animals tested. Liver tissue samples had the highest frequency of detection (62%), followed by feces (41.4%) and gastric contents (30.4%). PbTx was not detected in urine or intestinal tissue. The concentration ranges of PbTx detected in feces (1.2-216, mean 38.4 ng/g), gastric contents (3.3-1016, mean 158 ng/g) and liver (0.6-52.4, mean 8.5 ng/g) samples were an order of magnitude less than values reported for Florida dolphins for the same sample types. The proportion of dolphins recovered within 4 weeks of a bloom that tested positive for PbTx ('Bloom' group; 75%) was significantly higher compared to those that were recovered 5-8 weeks after termination of a bloom ('Post-Bloom' group; 36%; p = 0.004). The proportion of PbTx-positive animals with no observed bloom association ('Baseline' group; 60%) was also significantly greater than the Post-Bloom group (p = 0.012). No significant difference in proportion of PbTx-positive animals was detected between Bloom and Baseline groups (p = 0.242). No significant differences in liver PbTx concentrations were observed between any pairwise combinations of the 3 exposure groups (p = 0.261). Overall, these findings suggest persistent PbTx exposure for many individuals in these populations, although the health impacts of such exposure are not known.

Fire SE, Leighfield TA, Miller GA, Piwetz S, Sabater E, Whitehead H (2020). Association between red tide exposure and detection of corresponding neurotoxins in bottlenose dolphins from Texas waters during 2007-2017.  Marine Environmental Research 162:105191.


Feel free to contact me directly for any comments or questions.
Best regards,


Spencer Fire, Ph.D.
Asst. Professor of Biological Sciences
Florida Institute of Technology
150 W. University Blvd.
Melbourne, FL 32901
sfire at fit.edu<mailto:sfire at fit.edu>
The Fire Lab website<https://firelabfit.weebly.com/>
The Fire Lab on Instagram<https://www.instagram.com/thefirelab/>

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