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Flewelling, Leanne J.; Naar, Jerome P.; Abbott, Jay P.; Baden, Daniel G.; Barros, Nélio B.; Bossart, Gregory D.; Bottein, Marie-Yasmine D.; Hammond, Daniel G.; Haubold, Elsa M.; Heil, Cynthia A.; Henry, Michael S.; Jacocks, Henry M.; Leighfield, Tod A.; Pierce, Richard H.; Pitchford, Thomas D.; Rommel, Sentiel A.; Scott, Paula S.; Steidinger, Karen A.; Truby, Earnest W.; Van Dolah, Frances M.; Landsberg, Jan H.
(detail)
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2005 |
Red tides and marine mammal mortalities.
Nature 435(7043): 755-756. 2 figs.
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Landsberg, Jan H.; Flewelling, Leanne J.; Naar, Jerome P.
(detail)
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2009 |
Karenia brevis red tides, brevetoxins in the food web, and impacts on natural resources: Decadal advancements.
Harmful Algae 8(4): 598-607. 2 tabs. 5 figs. DOI: 10.1016/j.hal.2008.11.010. Mar. 2009.
–ABSTRACT: As recently as a decade ago, Karenia brevis red tides and their effects on animal resources in the Gulf of Mexico were principally perceived as acute blooms that caused massive fish kills. Although occasional mortalities of higher vertebrates were documented, it has only been in the past decade that conclusive evidence has unequivocally demonstrated that red tides and their brevetoxins are lethal to these organisms. Brevetoxins can be transferred through the food chain and are accumulated in or transferred by biota at many trophic levels. The trophic transfer of brevetoxins in the food web is a complex phenomenon, one that is far more complicated than originally conceived. Unexplained fish kills and other animal mortalities in areas where red tide is endemic are being increasingly linked with post-bloom exposures of biota to brevetoxins. Mass mortality events of endangered Florida manatees (Trichechus manatus latirostris) follow a consistent spatial and temporal pattern, occurring primarily in the spring in southwestern Florida. Persistent blooms can also cause a cascade of environmental changes, affecting the ecosystem and causing widespread die-offs of benthic communities. Ongoing fish kills from sustained blooms can lead to short-term declines in local populations. Although animal populations in areas where red tide is endemic are unquestionably at risk, it remains to be determined to what extent populations can continue to recover from these sustained effects.
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11223 |
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Capper, Angela; Flewelling, Leanne J.; Arthur, Karen
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2013 |
Dietary exposure to harmful algal bloom (HAB) toxins in the endangered manatee (Trichechus manatus latirostris) and green sea turtle (Chelonia mydas) in Florida, USA.
Harmful Algae 26:1-9. DOI: 10.1016/j.hal.2013.04.009. Aug. 2013.
–ABSTRACT: Florida is a hotspot for cyano- and microalgal harmful algal blooms (HABs) with annual red-tide events off-shore and blooms of Lyngbya spp. commonly observed in both marine and freshwater environments. This region also provides extensive foraging habitat for large populations of herbivorous green turtles (Chelonia mydas) and manatees (Trichechus manatus latirostris). The exposure of aquatic organisms to HAB toxins is not well known and whilst acute exposures are better understood, the vulnerability of aquatic animals to chronic exposure from multiple HAB toxins over prolonged periods has rarely been addressed. This study aimed to identify the presence of toxic compounds produced by HAB species commonly found in Florida (brevetoxins, okadaic acid, saxitoxins and Lyngbya toxins) in tissues and gut samples from manatee and green sea turtles that stranded in Florida, USA. Muscle, liver and alimentary tract samples were opportunistically collected from 14 manatees and 13 green turtles that stranded on the Florida shoreline between December 2003 and February 2006. Samples from each animal were assessed for the presence of brevetoxin, okadaic acid, lyngbyatoxin-A and saxitoxin. Nine (64%) manatees and 11 (85%) turtles were found to have been exposed to one or more of the HAB toxins. Okadaic acid and saxitoxin were only found in alimentary tract samples, whereas brevetoxin was more widely distributed. No lyngbyatoxin-A was observed in any tissue samples. The majority of turtles (13) stranded on the Atlantic coast between St. Johns and Monroe counties, with one on the Gulf coast at Bay County, whereas nine manatees were stranded on the Gulf coast between Levy and Lee counties, with the remaining five between Volusia and Brevard counties on the Atlantic coast. This HAB toxin screen has identified that a large proportion of a random sample of turtles and manatees that stranded in Florida in 2003–2006 were exposed to HAB toxins. Most of the concentrations measured were low, and the toxins were directly linked to the death of only three of these animals. However, the presence of these compounds, and in some cases the presence of multiple HAB toxins in individual animals, indicates that turtles and manatees in Florida are exposed to deleterious compounds at sub-lethal levels in their environment, which could ultimately compromise their health.
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Fire, Spencer E.; Flewelling, Leanne J.; Stolen, Megan; Durden, Wendy Noke; De Wit, Martine; Spellman, Ann C.; Wang, Zhihong
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2015 |
Brevetoxin-associated mass mortality event of bottlenose dolphins and manatees along the east coast of Florida, USA.
Marine Ecology Progress Series 526: 241-251. 2 tabs. 4 figs. DOI: 10.3354/meps11225. Apr. 22, 2015.
–ABSTRACT: A mass mortality of bottlenose dolphins Tursiops truncatus and Florida manatees Trichechus manatus latirostris 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 the tested carcasses of manatees and dolphins, respectively, at concentrations similar to those reported for earlier mortality events along the west coast of Florida. 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.
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Walsh, Catherine J.; Butawan, Matthew; Yordy, Jennifer; Ball, Ray; Flewelling, Leanne; De Wit, Martine; Bonde, Robert K.
(detail)
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2015 |
Sublethal red tide toxin exposure in free-ranging manatees (Trichechus manatus) affects the immune system through reduced lymphocyte proliferation responses, inflammation, and oxidative stress.
Aquatic Toxicology 161: 73-84. DOI: 10.1016/j.aquatox.2015.01.019
–ABSTRACT: The health of many Florida manatees (Trichechus manatus latirostris) is adversely affected by exposure to blooms of the toxic dinoflagellate, Karenia brevis. K. brevis blooms are common in manatee habitats off Florida's southwestern coast and produce a group of cyclic polyether toxins collectively referred to as red tide toxins, or brevetoxins. Although a large number of manatees exposed to significant levels of red tide toxins die, several manatees are rescued from sublethal exposure and are successfully treated and returned to the wild. Sublethal brevetoxin exposure may potentially impact the manatee immune system. Lymphocyte proliferative responses and a suite of immune function parameters in the plasma were used to evaluate effects of brevetoxin exposure on health of manatees rescued from natural exposure to red tide toxins in their habitat. Blood samples were collected from rescued manatees at Lowry Park Zoo in Tampa, FL and from healthy, unexposed manatees in Crystal River, FL. Peripheral blood leukocytes (PBL) isolated from whole blood were stimulated with T-cell mitogens, ConA and PHA. A suite of plasma parameters, including plasma protein electrophoresis profiles, lysozyme activity, superoxide dismutase (SOD) activity, and reactive oxygen/nitrogen (ROS/RNS) species, was also used to assess manatee health. Significant decreases (P < 0.05) in lymphocyte proliferation were observed in ConA and PHA stimulated lymphocytes from rescued animals compared to non-exposed animals. Significant correlations were observed between oxidative stress markers (SOD, ROS/RNS) and plasma brevetoxin concentrations. Sublethal exposure to brevetoxins in the wild impacts some immune function components, and thus overall health, in the Florida manatee.
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Bibliography and Index of the Sirenia and Desmostylia 