Vulnerability to climate change of United States marine mammal stocks in the western North Atlantic, Gulf of Mexico, and Caribbean.

Climate change and climate variability are affecting marine mammal species and these impacts are projected to continue in the coming decades. Vulnerability assessments provide a framework for evaluating climate impacts over a broad range of species using currently available information. We conducted a trait-based climate vulnerability assessment using expert elicitation for 108 marine mammal stocks and stock groups in the western North Atlantic, Gulf of Mexico, and Caribbean Sea. Our approach combined the exposure (projected change in environmental conditions) and sensitivity (ability to tolerate and adapt to changing conditions) of marine mammal stocks to estimate vulnerability to climate change, and categorize stocks with a vulnerability index. The climate vulnerability score was very high for 44% (n = 47) of these stocks, high for 29% (n = 31), moderate for 20% (n = 22), and low for 7% (n = 8). The majority of stocks (n = 78; 72%) scored very high exposure, whereas 24% (n = 26) scored high, and 4% (n = 4) scored moderate. The sensitivity score was very high for 33% (n = 36) of these stocks, high for 18% (n = 19), moderate for 34% (n = 37), and low for 15% (n = 16). Vulnerability results were summarized for stocks in five taxonomic groups: pinnipeds (n = 4; 25% high, 75% moderate), mysticetes (n = 7; 29% very high, 57% high, 14% moderate), ziphiids (n = 8; 13% very high, 50% high, 38% moderate), delphinids (n = 84; 52% very high, 23% high, 15% moderate, 10% low), and other odontocetes (n = 5; 60% high, 40% moderate). Factors including temperature, ocean pH, and dissolved oxygen were the primary drivers of high climate exposure, with effects mediated through prey and habitat parameters. We quantified sources of uncertainty by bootstrapping vulnerability scores, conducting leave-one-out analyses of individual attributes and individual scorers, and through scoring data quality for each attribute. These results provide information for researchers, managers, and the public on marine mammal responses to climate change to enhance the development of more effective marine mammal management, restoration, and conservation activities that address current and future environmental variation and biological responses due to climate change.

Challenges in small cetacean telemetry: an attempt at developing a remotely deployed attachment device for single-pin dorsal fin satellite transmitters.

Satellite telemetry is critical for collecting fine-scale temporal and spatial data on individual animals that has broad-scale applicability at population and species levels. There have been significant advances in the remote deployment of satellite telemetry devices on large cetacean species. However, the development of comparable remote attachment methodologies for small cetaceans is still limited. Currently, satellite tag attachment for small cetaceans requires manual capture that increases the risk to the target animal, can be logistically challenging, and cost prohibitive. The goal of this project was to develop a novel tool to remotely attach single-pin satellite telemetry devices to the dorsal fin of individual small cetaceans. Three different spring-loaded designs and one pneumatic version of the remote attachment device were built in an iterative process to identify a successful deployment methodology. Ultimately, as a result of logistical challenges associated with a Category 5 hurricane, the COVID-19 pandemic, and engineering complexities related to dorsal fin morphology and small cetacean behavior, the objective of this project was not met. However, lessons learned from these attempts to develop this new sampling tool have applicability for future researchers in the successful completion of a safe and effective methodology for remote attachment of satellite tags to small cetacean dorsal fins.

Exploring the Use of SEM-EDS Analysis to Measure the Distribution of Major, Minor, and Trace Elements in Bottlenose Dolphin (Tursiops truncatus) Teeth.

Dolphin teeth contain enamel, dentin, and cementum. In dentin, growth layer groups (GLGs), deposited at incremental rates (e.g., annually), are used for aging. Major, minor, and trace elements are incorporated within teeth; their distribution within teeth varies, reflecting tooth function and temporal changes in an individual's exposure. This study used a scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) to determine the distribution of major (e.g., Ca, P), minor (e.g., Cl, Mg, Na), and trace elements (e.g., Cd, Hg, Pb, Zn) in teeth from 12 bottlenose dolphins (Tursiops truncatus). The objective was to compare elemental distributions between enamel and dentin and across GLGs. Across all dolphins and point analyses, the following elements were detected in descending weight percentage (wt %; mean ± SE): O (40.8 ± 0.236), Ca (24.3 ± 0.182), C (14.3 ± 0.409), P (14.0 ± 0.095), Al (4.28 ± 0.295), Mg (1.89 ± 0.047), Na (0.666 ± 0.008), Cl (0.083 ± 0.003). Chlorine and Mg differed between enamel and dentin; Mg increased from the enamel towards the dentin while Cl decreased. The wt % of elements did not vary significantly across the approximate location of the GLGs. Except for Al, which may be due to backscatter from the SEM stub, we did not detect trace elements. Other trace elements, if present, are below the detection limit. Technologies with lower detection limits (e.g., laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS)) would be required to confirm the presence and distribution of trace elements in bottlenose dolphin teeth.

Age determination of common bottlenose dolphins (Tursiops truncatus) using dental radiography pulp:tooth area ratio measurements.

Age is an important parameter to better understand wildlife populations, and is especially relevant for interpreting data for fecundity, health, and survival assessments. Estimating ages for marine mammals presents a particular challenge due to the environment they inhabit: accessibility is limited and, when temporarily restrained for assessment, the window of opportunity for data collection is relatively short. For wild dolphins, researchers have described a variety of age-determination techniques, but the gold-standard relies upon photo-identification to establish individual observational life histories from birth. However, there are few populations with such long-term data sets, therefore alternative techniques for age estimation are required for individual animals without a known birth period. While there are a variety of methods to estimate ages, each involves some combination of drawbacks, including a lack of precision across all ages, weeks-to-months of analysis time, logistical concerns for field applications, and/or novel techniques still in early development and validation. Here, we describe a non-invasive field technique to determine the age of small cetaceans using periapical dental radiography and subsequent measurement of pulp:tooth area ratios. The technique has been successfully applied for bottlenose dolphins briefly restrained during capture-release heath assessments in various locations in the Gulf of Mexico. Based on our comparisons of dental radiography data to life history ages, the pulp:tooth area ratio method can reliably provide same-day estimates for ages of dolphins up to about 10 years old.

Occurrence of Brucella ceti in stranded bottlenose dolphins Tursiops truncatus coincides with calving season.

Brucellosis is a disease caused by the Gram-negative facultative intracellular bacterium Brucella spp. In terrestrial species, this zoonotic bacterium is a global public health risk, but there is also concern over the zoonotic potential of marine forms, such as B. ceti, which affects cetaceans. Due to the detection of B. ceti in samples from bottlenose dolphins Tursiops truncatus during the 2010-2014 Gulf of Mexico Unusual Mortality Event, a long-term study of the prevalence of Brucella in stranded bottlenose dolphins from South Carolina, USA, was conducted. From 2012 through 2017, 282 stranded bottlenose dolphins were tested for B. ceti via real-time PCR. Nearly 32% of the dolphins tested positive in at least one sample (brain, lung, blowhole swab). Very little information exists in the literature on the occurrence of Brucella spp. in marine mammals, though in terrestrial species, such as cattle and elk, higher prevalence is often reported in spring. Similar results were found in this study with the peak occurrence being between March and June, a known period of calving in South Carolina. Results from this study provide important insights into the occurrence of the marine bacterium B. ceti.

Health impacts of environmental contamination of micro- and nanoplastics: a review.

Plastics are extensively used in our daily life. However, a significant amount of plastic waste is discharged to the environment directly or via improper reuse or recycling. Degradation of plastic waste generates micro- or nano-sized plastic particles that are defined as micro- or nanoplastics (MNPs). Microplastics (MPs) are plastic particles with a diameter less than 5 mm, while nanoplastics (NPs) range in diameter from 1 to 100 or 1000 nm. In the current review, we first briefly summarized the environmental contamination of MNPs and then discussed their health impacts based on existing MNP research. Our review indicates that MNPs can be detected in both marine and terrestrial ecosystems worldwide and be ingested and accumulated by animals along the food chain. Evidence has suggested the harmful health impacts of MNPs on marine and freshwater animals. Recent studies found MPs in human stool samples, suggesting that humans are exposed to MPs through food and/or drinking water. However, the effect of MNPs on human health is scarcely researched. In addition to the MNPs themselves, these tiny plastic particles can release plastic additives and/or adsorb other environmental chemicals, many of which have been shown to exhibit endocrine disrupting and other toxic effects. In summary, we conclude that more studies are necessary to provide a comprehensive understanding of MNP pollution hazards and also provide a basis for the subsequent pollution management and control.

Mercury concentrations in blubber and skin from stranded bottlenose dolphins (Tursiops truncatus) along the Florida and Louisiana coasts (Gulf of Mexico, USA) in relation to biological variables.

Due to their long life-span and top trophic position, odontocetes can accumulate high concentrations of mercury (Hg) in their tissues. This study measured the concentration of total Hg (THg) in the blubber and skin of bottlenose dolphins (Tursiops truncatus) that stranded along the Florida (FL) panhandle and Louisiana (LA) coasts and investigated the relationship between total Hg (THg) concentration and sex, body length, age, stranding location, diet/trophic position (δ13C and δ15N, respectively), and foraging habitat (δ34S). Additionally, we compared models using body length and age as explanatory variables to determine which was a better predictor of THg concentration. In both tissues, sex was not an influential predictor of THg concentration and there was a positive relationship between body length/age and THg concentration (p < 0.001). Florida dolphins had greater mean blubber and skin THg concentrations compared to LA dolphins (p < 0.001). There was a modest improvement in model fit when age was used in place of body length. δ13C, δ15N, and δ34S differed between stranding locations and together with age were significant predictors of THg concentrations (R2 = 0.52, P < 0.001). Florida dolphins were δ13C enriched compared to LA dolphins (p < 0.001) and THg concentrations were positively correlated with δ13C (R2 = 0.22, p < 0.001). Our results demonstrate spatial variability in THg concentrations from stranded bottlenose dolphins from the northern Gulf of Mexico; however, future research is required to understand how fine-scale population structuring of dolphins within FL and LA impacts THg concentrations, particularly among inshore (bay, sound, and estuary) stocks and between inshore and offshore stocks, as variations in biotic and abiotic conditions can influence both stable isotope ratios and THg concentrations.

Evidence for cortisol-cortisone metabolism by marine mammal blubber.

Blubber, a specialized hyperdermic adipose tissue found in marine mammals, has been identified as a useful tissue for the assessment of steroid hormone homeostasis in cetaceans. However, blubber cortisol measurements are not quantitatively predictive of circulating cortisol concentrations in bottlenose dolphins. In other mammals, adipose tissue metabolizes steroid hormones. Thus, it is proposed that the disagreement between blubber and blood cortisol in bottlenose dolphins could be due in part to metabolism of corticosteroids in blubber. The purpose of this study is to characterize the ability of blubber to interconvert cortisol and cortisone using an in vitro design. Results demonstrate that bottlenose dolphin blubber microsomes interconvert cortisol and cortisone, an effect that is abated by denaturing the microsomes, indicating this is an enzymatic process. These findings lead to the conclusion that blubber is likely a site of active steroid metabolism, which should be considered in future studies utilizing blubber as a matrix for endocrine assessment.

Ranging patterns, spatial overlap, and association with dolphin morbillivirus exposure in common bottlenose dolphins (Tursiops truncatus) along the Georgia, USA coast.

During 2013-2015, an outbreak of dolphin morbillivirus (DMV) occurred in the western North Atlantic, which resulted in the stranding of over 1,600 common bottlenose dolphins (Tursiops truncatus). There are currently five coastal and 10 bay, sound, and estuary dolphin stocks along the U.S. Atlantic coast, yet there is very limited understanding of which stocks were exposed to DMV during the recent outbreak, or how DMV was transmitted across stocks. In order to address these questions, information is needed on spatial overlap and stock interactions. The goals of this project were to determine ranging patterns, prevalence of DMV, and spatial overlap of the South Carolina-Georgia (SC-GA) Coastal Stock, and adjacent Southern Georgia Estuarine System (SGES) Stock. During September 2015, a health assessment and telemetry study was conducted in which 19 dolphins were captured, tested for antibodies to DMV, and satellite tagged. Dolphins were classified into one of three ranging patterns (Coastal, Sound, or Estuary) based upon telemetry data. Coastal dolphins (likely members of the SC-GA Coastal Stock) had a significantly higher prevalence of positive DMV antibody titers (0.67; N = 2/3), than Sound and Estuary dolphins (likely members of the SGES Stock) (0.13; N = 2/16). These results suggest that the SC-GA Coastal Stock may have experienced greater exposure to DMV as compared to the SGES Stock. However, due to the small size of the SGES Stock and its exposure to high levels of persistent contaminants, this stock may be particularly vulnerable to DMV infection in the future.

Selenium protein identification and profiling by mass spectrometry: A tool to assess progression of cardiomyopathy in a whale model.

Non-ischemic cardiomyopathy is a leading cause of congestive heart failure and sudden cardiac death in humans and in some cases the etiology of cardiomyopathy can include the downstream effects of an essential element deficiency. Of all mammal species, pygmy sperm whales (Kogia breviceps) present the greatest known prevalence of cardiomyopathy with more than half of examined individuals indicating the presence of cardiomyopathy from gross and histo-pathology. Several factors such as genetics, infectious agents, contaminants, biotoxins, and inappropriate dietary intake (vitamins, selenium, mercury, and pro-oxidants), may contribute to the development of idiopathic cardiomyopathy in K. breviceps. Due to the important role Se can play in antioxidant biochemistry and protein formation, Se protein presence and relative abundance were explored in cardiomyopathy related cases. Selenium proteins were separated and detected by multi-dimension liquid chromatography inductively coupled plasma mass spectrometry (LC-ICP-MS), Se protein identification was performed by liquid chromatography electrospray tandem mass spectrometry (LC-ESI-MS/MS), and Se protein profiles were examined in liver (n=30) and heart tissue (n=5) by SEC/UV/ICP-MS detection. Data collected on selenium proteins was evaluated in the context of individual animal trace element concentration, life history, and histological information. Selenium containing protein peak profiles varied in presence and intensity between animals with no pathological findings of cardiomyopathy and animals exhibiting evidence of cardiomyopathy. In particular, one class of proteins, metallothioneins, was found to be associated with Se and was in greater abundance in animals with cardiomyopathy than those with no pathological findings. Profiling Se species with SEC/ICP-MS proved to be a useful tool to identify Se protein pattern differences between heart disease stages in K. breviceps and an approach similar to this may be applied to other species to study Se protein associations with cardiomyopathy.

Rapid and reliable steroid hormone profiling in Tursiops truncatus blubber using liquid chromatography tandem mass spectrometry (LC-MS/MS).

Monitoring of marine mammal steroid hormone status using matrices alternative to blood is desirable due to the ability to remotely collect samples, which minimizes stress to the animal. However, measurement techniques in alternative matrices such as blubber described to date are limited in the number and types of hormones measured. Therefore, a new method using bead homogenization to QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) extraction, C18 post extraction cleanup and analysis by liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed and applied to the measurement of hormone suites in bottlenose dolphin blubber. Validations were conducted in blubber from fresh dead stranded bottlenose dolphin. The final method consisting of two LC separations and garnet bead homogenization was tested for extraction efficiencies. Steroids were separated using a biphenyl column for reproductive hormones and C18 column for corticosteroids. Three hormones previously noted in blubber, testosterone, progesterone, and cortisol, were quantified in addition to previously unmeasured androstenedione, 17-hydroxyprogesterone, 11-deoxycortisol, 11-deoxycorticosterone, and cortisone in a single sample (0.4 g blubber). Extraction efficiencies of all hormones from blubber ranged from 84% to 112% and all RSDs were comparable to those reported using immunoassay methods (< 15%). The method was successfully applied to remote biopsied blubber samples to measure baseline hormone concentrations. Through this method, increased coverage of steroid hormone pathways from a single remotely collected sample potentially enhances the ability to interpret biological phenomena such as reproduction and stress in wild dolphin populations. Graphical abstract The steroid hormone profile is quantifiable from a single sample of bottlenose dolphin blubber using liquid chromatography tandem mass spectrometry. This profile can be applied to remotely collected dart biopsies and be used to determine reproductive or stress status of a wild-living dolphin.

Evaluation of Serum for Pathophysiological Effects of Prolonged Low Salinity Water Exposure in Displaced Bottlenose Dolphins (Tursiops truncatus).

We conducted a retrospective study of serum biochemistry and hematologic findings from displaced, out-of-habitat bottlenose dolphins (Tursiops truncatus) exposed to various low salinity environments in waters along the southern United States including southeastern Atlantic and northern Gulf of Mexico. Serum sodium, chloride, and calculated osmolality were significantly lower and below reference ranges in displaced animals compared to free-ranging case control animals. This suggests clinical hyponatremia, hypochloremia, and hypo-osmolality due to an uptake of low saline water from the environment. In addition, significant differences were found in other serum chemistry variables, although none were outside of normal reference ranges for non-controlled free-ranging animals. Multiple linear regressions demonstrated the degree of salinity had a greater pathophysiologic response than the duration of fresh water exposure. The Na/Cl ratio and bicarbonate were the only variables that were significantly modulated by exposure duration. These findings suggest that the degree of salinity is a critical factor when assessing and managing care for dolphins chronically exposed to low salinity water. Results from this study indicate that changes in various biochemical parameters can be used to determine fresh water exposure and aid in determining the treatment for animals recovered from low salinity waters.

Detection of Brucella spp. in bottlenose dolphins Tursiops truncatus by a real-time PCR using blowhole swabs.

Blowhole swabs are a simple and non-invasive method for collecting samples from cetaceans and can be used for screening large numbers of animals in the field. This study reports a real-time PCR assay for the detection of Brucella spp. using blowhole swab samples from bottlenose dolphins Tursiops truncatus stranded in the coastal region of Virginia, South Carolina and northern Florida, USA, between 2013 and 2015. We used real-time PCR results on lung samples from the same dolphins in order to estimate the relative sensitivity and specificity of real-time PCR of blowhole swabs. Brucella DNA was detected in lung tissue of 22% (18/81) and in blowhole swabs of 21% (17/81) of the sampled dolphins. The relative sensitivity and specificity of real-time PCR on blowhole swabs as compared to the real-time PCR on lung samples was 94% (17/18) and 100% (63/63), respectively. These results indicate that real-time PCR on blowhole swabs may be used as a non-invasive test for rapid detection of Brucella spp. in the respiratory tract of dolphins. To our knowledge, this is the first report on the use of blowhole swabs for detection of bacterial pathogens by real-time PCR in bottlenose dolphins.

Fetal distress and in utero pneumonia in perinatal dolphins during the Northern Gulf of Mexico unusual mortality event.

An unusual mortality event (UME) involving primarily common bottlenose dolphins Tursiops truncatus of all size classes stranding along coastal Louisiana, Mississippi, and Alabama, USA, started in early 2010 and continued into 2014. During this northern Gulf of Mexico UME, a distinct cluster of perinatal dolphins (total body length <115 cm) stranded in Mississippi and Alabama during 2011. The proportion of annual dolphin strandings that were perinates between 2009 and 2013 were compared to baseline strandings (2000-2005). A case-reference study was conducted to compare demographics, histologic lesions, and Brucella sp. infection prevalence in 69 UME perinatal dolphins to findings from 26 reference perinates stranded in South Carolina and Florida outside of the UME area. Compared to reference perinates, UME perinates were more likely to have died in utero or very soon after birth (presence of atelectasis in 88 vs. 15%, p < 0.0001), have fetal distress (87 vs. 27%, p < 0.0001), and have pneumonia not associated with lungworm infection (65 vs. 19%, p = 0.0001). The percentage of perinates with Brucella sp. infections identified via lung PCR was higher among UME perinates stranding in Mississippi and Alabama compared to reference perinates (61 vs. 24%, p = 0.01), and multiple different Brucella omp genetic sequences were identified in UME perinates. These results support that from 2011 to 2013, during the northern Gulf of Mexico UME, bottlenose dolphins were particularly susceptible to late-term pregnancy failures and development of in utero infections including brucellosis.

A Bayesian mixture model for missing data in marine mammal growth analysis.

Much of what is known about bottle nose dolphin (Tursiops truncatus) anatomy and physiology is based on necropsies from stranding events. Measurements of total body length, total body mass, and age are used to estimate growth. It is more feasible to retrieve and transport smaller animals for total body mass measurement than larger animals, introducing a systematic bias in sampling. Adverse weather events, volunteer availability, and other unforeseen circumstances also contribute to incomplete measurement. We have developed a Bayesian mixture model to describe growth in detected stranded animals using data from both those that are fully measured and those not fully measured. Our approach uses a shared random effect to link the missingness mechanism (i.e. full/partial measurement) to distinct growth curves in the fully and partially measured populations, thereby enabling drawing of strength for estimation. We use simulation to compare our model to complete case analysis and two common multiple imputation methods according to model mean square error. Results indicate that our mixture model provides better fit both when the two populations are present and when they are not. The feasibility and utility of our new method is demonstrated by application to South Carolina strandings data.

A survey of trace element distribution in tissues of the dwarf sperm whale (Kogia sima) stranded along the South Carolina coast from 1990-2011.

Few studies report trace elements in dwarf sperm whale (Kogia sima). As high trophic level predators, marine mammals are exposed through diet to environmental contaminants including metals from anthropogenic sources. Inputs of Hg, Pb, and Cd are of particular concern due to toxicity and potential for atmospheric dispersion and subsequent biomagnification. Liver and kidney tissues of stranded K. sima from coastal South Carolina, USA, were analyzed for 22 trace elements. Age-related correlations with tissue concentrations were found for some metals. Mean molar ratio of Hg:Se varied with age with higher ratios found in adult males. Maximum concentrations of Cd and Hg in both tissues exceeded historical FDA levels of concern, but none exceeded the minimum 100µg/g Hg threshold for hepatic damage. Tissue concentrations of some metals associated with contamination were low, suggesting that anthropogenic input may not be a significant source of some metals for these pelagic marine mammals.

Adrenal Gland and Lung Lesions in Gulf of Mexico Common Bottlenose Dolphins (Tursiops truncatus) Found Dead following the Deepwater Horizon Oil Spill.

A northern Gulf of Mexico (GoM) cetacean unusual mortality event (UME) involving primarily bottlenose dolphins (Tursiops truncatus) in Louisiana, Mississippi, and Alabama began in February 2010 and continued into 2014. Overlapping in time and space with this UME was the Deepwater Horizon (DWH) oil spill, which was proposed as a contributing cause of adrenal disease, lung disease, and poor health in live dolphins examined during 2011 in Barataria Bay, Louisiana. To assess potential contributing factors and causes of deaths for stranded UME dolphins from June 2010 through December 2012, lung and adrenal gland tissues were histologically evaluated from 46 fresh dead non-perinatal carcasses that stranded in Louisiana (including 22 from Barataria Bay), Mississippi, and Alabama. UME dolphins were tested for evidence of biotoxicosis, morbillivirus infection, and brucellosis. Results were compared to up to 106 fresh dead stranded dolphins from outside the UME area or prior to the DWH spill. UME dolphins were more likely to have primary bacterial pneumonia (22% compared to 2% in non-UME dolphins, P = .003) and thin adrenal cortices (33% compared to 7% in non-UME dolphins, P = .003). In 70% of UME dolphins with primary bacterial pneumonia, the condition either caused or contributed significantly to death. Brucellosis and morbillivirus infections were detected in 7% and 11% of UME dolphins, respectively, and biotoxin levels were low or below the detection limit, indicating that these were not primary causes of the current UME. The rare, life-threatening, and chronic adrenal gland and lung diseases identified in stranded UME dolphins are consistent with exposure to petroleum compounds as seen in other mammals. Exposure of dolphins to elevated petroleum compounds present in coastal GoM waters during and after the DWH oil spill is proposed as a cause of adrenal and lung disease and as a contributor to increased dolphin deaths.

Real-time PCR assays for detection of Brucella spp. and the identification of genotype ST27 in bottlenose dolphins (Tursiops truncatus).

Rapid detection of Brucella spp. in marine mammals is challenging. Microbiologic culture is used for definitive diagnosis of brucellosis, but is time consuming, has low sensitivity and can be hazardous to laboratory personnel. Serological methods can aid in diagnosis, but may not differentiate prior exposure versus current active infection and may cross-react with unrelated Gram-negative bacteria. This study reports a real-time PCR assay for the detection of Brucella spp. and application to screen clinical samples from bottlenose dolphins stranded along the coast of South Carolina, USA. The assay was found to be 100% sensitive for the Brucella strains tested, and the limit of detection was 0.27fg of genomic DNA from Brucella ceti B1/94 per PCR volume. No amplification was detected for the non-Brucella pathogens tested. Brucella DNA was detected in 31% (55/178) of clinical samples tested. These studies indicate that the real-time PCR assay is highly sensitive and specific for the detection of Brucella spp. in bottlenose dolphins. We also developed a second real-time PCR assay for rapid identification of Brucella ST27, a genotype that is associated with human zoonotic infection. Positive results were obtained for Brucella strains which had been identified as ST27 by multilocus sequence typing. No amplification was found for other Brucella strains included in this study. ST27 was identified in 33% (18/54) of Brucella spp. DNA-positive clinical samples. To our knowledge, this is the first report on the use of a real-time PCR assay for identification of Brucella genotype ST27 in marine mammals.

Health of common bottlenose dolphins ( Tursiops truncatus ) in Barataria Bay, Louisiana, following the deepwater horizon oil spill.

The oil spill resulting from the explosion of the Deepwater Horizon drilling platform initiated immediate concern for marine wildlife, including common bottlenose dolphins in sensitive coastal habitats. To evaluate potential sublethal effects on dolphins, health assessments were conducted in Barataria Bay, Louisiana, an area that received heavy and prolonged oiling, and in a reference site, Sarasota Bay, Florida, where oil was not observed. Dolphins were temporarily captured, received a veterinary examination, and were then released. Dolphins sampled in Barataria Bay showed evidence of hypoadrenocorticism, consistent with adrenal toxicity as previously reported for laboratory mammals exposed to oil. Barataria Bay dolphins were 5 times more likely to have moderate-severe lung disease, generally characterized by significant alveolar interstitial syndrome, lung masses, and pulmonary consolidation. Of 29 dolphins evaluated from Barataria Bay, 48% were given a guarded or worse prognosis, and 17% were considered poor or grave, indicating that they were not expected to survive. Disease conditions in Barataria Bay dolphins were significantly greater in prevalence and severity than those in Sarasota Bay dolphins, as well as those previously reported in other wild dolphin populations. Many disease conditions observed in Barataria Bay dolphins are uncommon but consistent with petroleum hydrocarbon exposure and toxicity.