title: Concurrent exposure of bottlenose dolphins (Tursiops truncatus) to multiple algal toxins in Sarasota Bay, Florida, USA.
abstract: Sentinel species such as bottlenose dolphins (Tursiops truncatus) can be impacted by large-scale mortality events due to exposure to marine algal toxins. In the Sarasota Bay region (Gulf of Mexico, Florida, USA), the bottlenose dolphin population is frequently exposed to harmful algal blooms (HABs) of Karenia brevis and the neurotoxic brevetoxins (PbTx; BTX) produced by this dinoflagellate. Live dolphins sampled during capture-release health assessments performed in this region tested positive for two HAB toxins; brevetoxin and domoic acid (DA). Over a ten-year study period (2000-2009) we have determined that bottlenose dolphins are exposed to brevetoxin and/or DA on a nearly annual basis (i.e., DA: 2004, 2005, 2006, 2008, 2009; brevetoxin: 2000, 2004, 2005, 2008, 2009) with 36% of all animals testing positive for brevetoxin (n = 118) and 53% positive for DA (n = 83) with several individuals (14%) testing positive for both neurotoxins in at least one tissue/fluid. To date there have been no previously published reports of DA in southwestern Florida marine mammals, however the May 2008 health assessment coincided with a Pseudo-nitzschia pseudodelicatissima bloom that was the likely source of DA observed in seawater and live dolphin samples. Concurrently, both DA and brevetoxin were observed in common prey fish. Although no Pseudo-nitzschia bloom was identified the following year, DA was identified in seawater, fish, sediment, snails, and dolphins. DA concentrations in feces were positively correlated with hematologic parameters including an increase in total white blood cell (p = 0.001) and eosinophil (p<0.001) counts. Our findings demonstrate that dolphins within Sarasota Bay are commonly exposed to two algal toxins, and provide the impetus to further explore the potential long-term impacts on bottlenose dolphin health.
authors.affiliation: Marine Biotoxins Program, National Oceanic and Atmospheric Administration/National Ocean Service, Charleston, South Carolina, United States of America. mtwiner@umd.umich.edu
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Twiner
authors.forename: Spencer
authors.initials: S
authors.lastname: Fire
authors.forename: Lori
authors.initials: L
authors.lastname: Schwacke
authors.forename: Leigh
authors.initials: L
authors.lastname: Davidson
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Wang
authors.forename: Steve
authors.initials: S
authors.lastname: Morton
authors.forename: Stephen
authors.initials: S
authors.lastname: Roth
authors.forename: Brian
authors.initials: B
authors.lastname: Balmer
authors.forename: Teresa K
authors.initials: TK
authors.lastname: Rowles
authors.forename: Randall S
authors.initials: RS
authors.lastname: Wells
mesh_terms: D000818:Animals; D050681:Bottle-Nosed Dolphin / Q000097:blood / Q000378:metabolism* / Q000652:urine; D002452:Cell Count; D004141:Dinoflagellida / Q000166:cytology / Q000187:drug effects; D004781:Environmental Exposure / Q000032:analysis*; D004784:Environmental Monitoring; D004804:Eosinophils / Q000166:cytology / Q000187:drug effects; D005243:Feces; D005399:Fishes / Q000378:metabolism; D005431:Florida; D005843:Geography; D006262:Health; D007608:Kainic Acid / Q000031:analogs & derivatives* / Q000633:toxicity; D016014:Linear Models; D008387:Marine Toxins / Q000633:toxicity*; D009792:Oceans and Seas; D035964:Oxocins / Q000633:toxicity*; D012908:Snails / Q000187:drug effects / Q000378:metabolism; D000095702:Polyether Toxins
chemical_list: D007608:Kainic Acid; D008387:Marine Toxins; D035964:Oxocins; C053342:brevetoxin; D000095702:Polyether Toxins; C012301:domoic acid