Abstract

A mass mortality of bottlenose dolphins (Tursiops truncatus, n = 14) and Florida manatees (Trichechus manatus latirostris, n = 33) co-occurred with a severe bloom of the toxic algal species Karenia brevis along the eastern coast of Florida, USA, between October 2007 and January 2008. Brevetoxin (PbTx), a potent neurotoxin produced by this marine alga, was detected in 69% and 92% of tested carcasses of manatees and dolphins, respectively, at concentrations similar to those reported for earlier mortality events along the west coast of Florida.^1-3 Brevetoxin was also detected in fetal and neonate dolphins, providing evidence of maternal transfer of the toxin in wild populations. This study is the first to document a brevetoxin-associated marine mammal mortality event along the Atlantic coast of Florida. It also demonstrates that, despite the rarity of K. brevis blooms in this region, significant negative impacts to marine mammals inhabiting this region can occur.

Acknowledgements

The authors would like to thank Karen Atwood (FWC), Brandon Bassett (FWC), Hannah Giddens (NOAA) and Leigh Davidson (NOAA) for assistance; FWC's marine mammal section staff for manatee event coordination and response; and Teresa Jablonski and HSWRI volunteers for dolphin stranding coordination and response (HSWRI). We thank Tod Leighfield (NOAA), Tina Mikulski (NOAA), Maggie Broadwater (NOAA), Noel Takeuchi (FWC) and Leslie Ward (FWC) for assistance in preparation and revisions of text.

* Presenting author

Literature Cited

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