11 research outputs found

    Report of 2009 Bottlenose Dolphin (Tursiops truncatus) Life History Workshop: expanding network capabilities

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    The Virginia Aquarium & Marine Science Center Foundation’s Stranding Response Program (VAQS) was awarded a grant in 2008 to conduct life history analysis on over 10 years of Tursiops truncatus teeth and gonad samples from stranded animals in Virginia. A major part of this collaborative grant included a workshop involving life historians from Hubbs-Sea World Research Institute (HSWRI), NOS, Texas A & M University (TAMU), and University of North Carolina Wilmington (UNCW). The workshop was held at the NOAA Center for Coastal Environmental Health & Biomolecular Research in Charleston, SC on 7-9 July 2009. The workshop convened to 1) address current practices among the groups conducting life history analysis, 2) decide on protocols to follow for the collaborative Prescott grant between VAQS and HSWRI, 3) demonstrate tissue preparation techniques and discuss shortcuts and pitfalls, 4) demonstrate data collection from prepared testes, ovaries, and teeth, and 5) discuss data analysis and prepare an outline and timeline for a future manuscript. The workshop concluded with discussions concerning the current collaborative Tursiops Life History Prescott grant award and the beginnings of a collaborative Prescott proposal with members of the Alliance of Marine Mammal Parks and Aquariums to further clarify reproductive analyses. This technical memorandum serves as a record of this workshop

    Fatal Asphyxiation in Bottlenose Dolphins (Tursiops truncatus) from the Indian River Lagoon.

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    Multiple single case reports of asphyxiation in dolphins caused by fish lodged in the esophagus exist. However, the significance of this cause of mortality in a single population has not been documented. We performed a retrospective evaluation of pathology records from stranded bottlenose dolphins (Tursiops truncatus) from the Indian River Lagoon to evaluate the impact of this cause of death on this population. From 1997 to 2011, asphyxiation due to choking was identified as the cause of death in 14 of 350 cases (4%). Sampling of an unrelated but adjacent population over this same period yielded 186 necropsy cases of bottlenose dolphins with no cases of asphyxiation. Asphyxiated animals presented with a fish lodged in the cranial esophagus associated with a dislocated and obstructed or compressed larynx. There was no clear sex predilection. Affected animals included 12 adults and two juveniles. The fish species involved included sheepshead, black chin tilapia and striped mojarra. In five cases, recreational fishing gear was also present. Cetacean choking is related to selection of prey fish species with strong dorsal spines and may be secondarily associated with fish attached to fishing gear. Prey abundance and dolphin behavior may influence these selections. Environmental alterations leading to changes in prey availability or increased interactions with fishing gear may change the significance of fatal choking in dolphin populations

    Photograph of dolphin with fish in esophagus.

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    <p>Photograph of IRL dolphin (Hubbs-1075) showing large fish displacing the laryngeal cartilage causing asphyxiation.</p

    Map of study area.

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    <p>Study area on the central east coast of Florida. The Indian River Lagoon is comprised of three interconnected water bodies separated from the Atlantic Ocean by barrier islands. Records of stranded dolphins that died of asphyxiation are symbolized as blue dots.</p

    Incidence of asphyxiation in IRL bottlenose dolphins (1997–2010).

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    *<p>Sizes of fish were estimated when only partial remains were available.</p

    Photograph of stranded dolphin with fish.

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    <p>Photograph of IRL dolphin (Hubbs-0723) with sheepshead lodged in the esophagus.</p

    Trace element bioaccumulation, tissue distribution, and elimination in odontocetes stranded in Florida and Georgia, USA over a 15-year period (2007–2021)

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    Odontocetes obtain nutrients including essential elements through their diet and are exposed to heavy metal contaminants via ingestion of contaminated prey. We evaluated the prevalence, concentration, and tissue distribution of essential and non-essential trace elements, including heavy metal toxicants, in tissue (blubber, kidney, liver, skeletal muscle, skin) and fecal samples collected from 90 odontocetes, representing nine species, that stranded in Georgia and Florida, USA during 2007–2021. Samples were analyzed for concentrations of seven essential (cobalt, copper, iron, manganese, molybdenum, selenium, zinc) and five non-essential (arsenic, cadmium, lead, mercury, thallium) elemental analytes using inductively-coupled plasma mass spectrometry. Risso's dolphins (Grampus griseus) and short-finned pilot whales (Globicephala macrorhynchus) had the highest median concentrations of mercury, cadmium, and lead, while dwarf sperm whales (Kogia sima) had the lowest. Adult pygmy and dwarf sperm whales that stranded in 2019–2021 had higher concentrations of arsenic, copper, iron, lead, manganese, selenium, thallium, and zinc compared to those that stranded in 2010–2018, suggesting an increasing risk of exposure over time. The highest concentrations of many elements (e.g., cadmium, cobalt, copper, manganese, molybdenum, thallium, zinc) were in fecal samples, illustrating the usefulness of this noninvasively collected sample. Aside from fecal samples, hepatic tissues had the highest concentrations of iron, manganese, mercury, molybdenum, and selenium in most species; renal tissues had the highest concentrations of cadmium; skin had the highest concentrations of zinc; and copper, arsenic, and lead concentrations were primarily distributed among the liver and kidneys. Phylogenetic differences in patterns of trace element concentrations likely reflect species-specific differences in diet, trophic level, and feeding strategies, while heterogeneous distributions of elemental analytes among different organ types reflect differences in elemental biotransformation, elimination, and storage. This study illustrates the importance of monitoring toxic contaminants in stranded odontocetes, which serve as important sentinels of environmental contamination, and whose health may be linked to human health

    Spatiotemporal movements of common bottlenose dolphins (Tursiops truncatus truncatus) in Northeast Florida, USA

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    Common bottlenose dolpliins (Tursiops inmca-tus truncatus) (hereafter referred to as dolpliins ) are distributed along the east coast of Florida in a longitudinal continuum within inland waterways and federally managed via assignment into stocks. Seven regional studies have identified local estuaiine populations with resident and seasonally transient dolpliins. However, study area boundaries limit understanding of distribution and movement patterns between these geographically separated regions. To reveal the bigger picture of spatiotemporal movements, a multi-organizational consortium conducted semiannual photo-identification surveys from the Florida-Georgia border to Titusville, Florida (331 km). The study area incorporated dolpliins occurring in the Jacksonville Estuaiine System (JES) stock in the north, the Mosquito Lagoon within the Indian River Lagoon Estuaiine System (IRLES-ML) stock in the south, and the connecting 156-km inland waterway currently managed under the Western North Atlantic Northern Florida and Central Florida coastal stocks. The area was divided into segments, and simultaneous surveys were conducted from 2011 to 2016 during two primary sampling seasons within each year: five summers and five winters (primary period), with two to three surveys (secondary sessions) within each primary period separated by one-week intervals to allow mixing of the population. A total of 6,896 dolpliins. including 196 neonates, were observed, and 649 individuals were identified. Spatial autocorrelation analyses of 222 marked dolphins sighted in \u3e 5 primary surveys revealed that 78fc exhibited significant regional and seasonal fidelity to one or more segments, which no single study could elucidate. Additionally, JES-North dolphins demonstrated strong regional site fidelity and were consistently sighted during both seasons, similar to studies in the 1990s, and continued to be partitioned from dolphins to the south. JES-Soutli and IRLES-ML dolphin home ranges extended beyond previously known boundaries. Based on spatiotem-poral movement patterns between the segments, recommendations are made to revise boundaries of the JES and IRLES stocks
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