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Organochlorine (OC) contaminant concentrations in tissues and lipid profiles in blubber are summarised for 101 gray whales (Eschrichtius robustus) from the eastern North Pacific stock. Samples were obtained from presumably healthy gray whales during a 1994 subsistence hunt in the Russian Arctic (n = 17) and also from biopsy sampling of live animals from the Washington coast (n = 38). In addition, tissues were collected from two groups of animals (1988-1991, n = 22; and 1999, n = 24) that stranded along the west coast of the USA. These whales represent a diverse group of animals with respect to lipid stores, age, gender, health and reproductive status. Information about these biological factors is necessary before contaminant concentration data can be properly interpreted. Differences in blubber lipid levels and profiles were examined among these groups of whales. Significantly higher lipid levels were found in the blubber of subsistence animals that were sampled following summer feeding in the Bering and Chukchi Seas, compared to lipid levels in the biopsied and stranded animals. Lipid class profiles from blubber of presumably healthy gray whales (i.e. from subsistence and biopsy sampling) contained primarily triglycerides and were very different from those of stranded animals that showed lipid decomposition (increased proportions of free fatty acids, cholesterol and phospholipids). Furthermore, lipid class profiles were found to be a means of estimating the quality of a blubber sample from stranded cetaceans. An examination of how biological factors (e.g. gender, reproductive status, age) contribute to interpreting the differences found in contaminant concentrations among the gray whales was also undertaken. Although not statistically significant, higher (OC) concentrations were found in males compared to females, thus suggesting the tendency of the mother to shift her contaminant burden to her calf during gestation and lactation. Results also indicated that there was no significant increase in concentrations of contaminants in the blubber with increase in length (surrogate for age). Higher concentrations of OC contaminants were found in stranded juvenile gray whales, compared to juvenile subsistence whales, and were thought to result from retention of OCs in blubber of the stranded animals as lipid stores are mobilised for energy and total lipid levels decrease, rather than from a difference in diet or feeding areas. OC concentrations in various tissues (blubber, liver, kidney, muscle, brain) were similar on a lipid weight basis, except for brain, which had lower lipid-adjusted OCs because the blood-brain barrier limits contaminant transfer.

The vaquita is the most critically endangered marine mammal, with fewer than 19 remaining in the wild. First described in 1958, the vaquita has been in rapid decline for more than 20 years resulting from inadvertent deaths due to the increasing use of large‐mesh gillnets. To understand the evolutionary and demographic history of the vaquita, we used combined long‐read sequencing and long‐range scaffolding methods with long‐ and short‐read RNA sequencing to generate a near error‐free annotated reference genome assembly from cell lines derived from a female individual. The genome assembly consists of 99.92% of the assembled sequence contained in 21 nearly gapless chromosome‐length autosome scaffolds and the X‐chromosome scaffold, with a scaffold N50 of 115 Mb. Genome‐wide heterozygosity is the lowest (0.01%) of any mammalian species analysed to date, but heterozygosity is evenly distributed across the chromosomes, consistent with long‐term small population size at genetic equilibrium, rather than low diversity resulting from a recent population bottleneck or inbreeding. Historical demography of the vaquita indicates long‐term population stability at less than 5,000 (Ne) for over 200,000 years. Together, these analyses indicate that the vaquita genome has had ample opportunity to purge highly deleterious alleles and potentially maintain diversity necessary for population health., see also the Perspective by Annabel Whibley

Noise is a stressor to wildlife, yet the precise sound sensitivity of individuals and populations is often unknown or unmeasured. Cook Inlet, Alaska belugas (CIBs) are a critically endangered and declining marine mammal population. Anthropogenic noise is a primary threat to these animals. Auditory evoked potentials were used to measure the hearing of a wild, stranded CIB as part of its rehabilitation assessment. The beluga showed broadband (4–128 kHz) and sensitive hearing (

Recent years have seen rapid development of tools and approaches to model population consequences of disturbance in several marine mammal populations from high-amplitude, acute sound sources. Ocean noise from shipping and other maritime activities is now recognized as a chronic, habitat-level stressor. In order to understand population consequences of chronic ocean noise to whales and their populations, advances are needed in several key areas, which are explored in this review. One tractable way to predict population-level consequences of noise-mediated disruption of feeding, which can include both behavioural responses and foraging opportunities lost due to acoustic masking. Masking may be defined as both the process and the amount by which the threshold of hearing of one sound is raised by the presence of another. Parameterising any such model requires information on sensitivity and vulnerability of large whales to ocean noise, in which sensitivity is the degree to which marine features respond to a stressor (e.g., behavioural responses to noise or proportional reduction in foraging efficiency due to masking), and vulnerability is the probability that whales are exposed noise to which they are sensitive. Efforts are underway to provide much-needed information on hearing sensitivity in baleen whales, the role of acoustic cues in foraging, and deriving links between long-term variability in prey availability and whale demography. As this information becomes available, we expect rapid advancement on modelling population consequences of acoustic masking in baleen whales, because those efforts can leverage substantial investments in statistical methodological approaches to model population consequences of disturbance. Pathways of effects other than via foraging disruption (e.g., stress hormones affecting reproduction or disease) are possible, but we illustrate potential ways to proceed based on this tractable approach, namely noise-mediated impacts on foraging. This report highlights case studies of local, national, international, and inter-governmental efforts to monitor and reduce the contribution of global shipping to ocean ambient noise. The following outlines approaches that can be used to assess the risk to baleen whale recovery of existing levels of ocean noise, and consequently, predict the benefits likely to arise from reducing chronic ocean noise.

Cardiac auscultation is an important, albeit underutilized tool in aquatic animal medicine due to the many challenges associated with in-water examinations. The aims of this prospective study were to (1) establish an efficient and repeatable in-water cardiac auscultation technique in bottlenose dolphins (Tursiops truncatus), (2) describe the presence and characterization of heart murmurs detected in free-ranging and managed dolphins, and (3) characterize heart murmur etiology through echocardiography in free-ranging dolphins. For technique development, 65 dolphins cared for by the Navy Marine Mammal Program (Navy) were auscultated. The techniques were then applied to two free-ranging dolphin populations during capture-release health assessments: Sarasota Bay, Florida (SB), a reference population, and Barataria Bay, LA (BB), a well-studied population of dolphins impacted by the Deepwater Horizon oil spill. Systolic heart murmurs were detected at a frequent and similar prevalence in all dolphin populations examined (Navy 92%, SB 89%, and BB 88%), and characterized as fixed or dynamic. In all three populations, sternal cranial and left cranial were the most common locations for murmur point of maximal intensity (PMI). An in-water transthoracic echocardiogram technique was refined on a subset of Navy dolphins, and full echocardiographic exams were performed on 17 SB dolphins and 29 BB dolphins, of which, 40 had murmurs. Spectral Doppler was used to measure flow velocities across the outflow tracts, and almost all dolphins with audible murmurs had peak outflow velocities ≥1.6 m/s (95%, 38/40); three dolphins also had medium mitral regurgitation which could be the source of their murmurs. The presence of audible murmurs in most of the free-ranging dolphins (88%) was attributed to high velocity blood flow as seen on echocardiography, similar to a phenomenon described in other athletic species. These innocent murmurs were generally characterized as Grade I-III systolic murmurs with PMI in the left or sternal cranial region. This study is the first to describe an efficient technique for in-water dolphin cardiac auscultation, and to present evidence that heart murmurs are common in bottlenose dolphins.

Variably buoyant, dead Cetacea may float, or sink and later bloat to refloat if ambient temperature and pressure allow sufficient decomposition gas formation and expansion. Mortality can result from acute or chronic disease, fishery entanglement, vessel collision, noxious noises, or toxicant spills. Investigators often face the daunting task of elucidating a complex series of events, in reverse order, from when and where an animal is found, and to diagnose the cause of death. Various scenarios are possible: an animal could die at sea remaining there or floating ashore, or strand on a beach alive, where it dies and, if cast high enough, remain beached to be scavenged or decompose. An animal that rests low on a beach may refloat again, through increased buoyancy from decomposition gas and favorable tides, currents, and wind. Here we review the factors responsible for the different outcomes, and how to recognize the provenance of a cetacean mortality found beached, or floating at sea. In conclusion, only some carcasses strand, or remain floating. Negatively buoyant animals that die at depth, or on the surface, and sink, may never surface, even after decomposition gas accumulation, as in cold, deep waters gas may fail to adequately reduce the density of a carcass, precluding it from returning to the surface.

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.

Systemic steroid hormone measurements are often used in the assessment of reproductive, developmental, and stress physiology in vertebrates. In protected wildlife, such as the common bottlenose dolphin (Tursiops truncatus), these measures can provide critical information about health and fitness to aid in effective conservation and management. Circulating steroid hormone concentrations are typically measured by immunoassays, which have imperfect specificity and are limited to the measurement of a single hormone per assay. Here we demonstrate that reverse phase solid phase extraction (SPE) coupled to liquid chromatography tandem mass spectrometry (LC-MS/MS) allows for the simultaneous, precise (< 15% relative standard deviation), and accurate (between 70% and 120% recovery of spiked quantities) measurement of at least seven steroid hormones in dolphin plasma. These seven steroid hormones include three hormones that have been measured previously in bottlenose dolphin blood (progesterone, testosterone, and cortisol) and three hormones which have never been quantified in dolphin blood (17-hydroxyprogesterone, androstenedione, cortisone, and corticosterone). While 17β-estradiol was not detected endogenously, we were able to accurately and precisely measure spiked quantities estradiol. Measures from plasma were more precise (i.e., lower RSD) than serum, and thus we recommend plasma as the preferred matrix for this analytical method. In order to facilitate comparison of current and future plasma-based studies to previous serum-based studies, we characterized the relationships between hormone measurements in matched plasma and serum, and found that measurements across matrices are significantly and positively correlated. Lastly, to demonstrate potential applications of this method, we examined how steroid hormone profiles vary by pregnancy, sexual maturity, and stress status – pregnancy was associated with elevated progesterone, adult males had higher testosterone, and capture stress was associated with elevated corticosteroids. Overall, we conclude that this method will enable investigators to more thoroughly and efficiently evaluate steroid hormone homeostasis in bottlenose dolphins compared to immunoassay methods. These methods can potentially be applied to the assessment of sexual maturity/seasonality, pregnancy status, and stress in free-ranging bottlenose dolphins as well as those maintained under human care, and potentially other marine mammals.

Due to an increase in pinniped strandings with consistent pathological findings throughout the North Atlantic coast of the United States during the summer and fall of 2006, an unusual mortal- ity event (UME) was declared by the National Oceanic and Atmospheric Administration's (NOAA) National Marine Fisheries Service (NMFS) on 20 October 2006. The goals of this investigation were to describe the magnitude and duration of the peak in mortalities involved in the UME and to evaluate associations with potential causative agents. Seal strandings during the UME were compared to historical strandings in the area to characterize the epidemiologic pat- terns of the UME. Temporal increases in phocine distemper virus (PDV) prevalence as detected by serology and polymerase chain reaction (PCR) were significantly correlated with increased seal stranding frequency. During July to October 2006, there was a significant spatial and tempo- ral cluster of PDV positive seals centered near Cape Ann, Massachusetts. Our findings provide evidence that PDV infections increased in harbor seals along the North Atlantic coast of the U.S. in 2006, and PDV likely played a role in a UME that involved harbor seals (Phoca vitulina), harp seals Phoca groenlandica), hooded seals (Cystophora cristata), and gray seals (Halichoerus grypus).

Understanding health and mortality in killer whales (Orcinus orca) is crucial for management and conservation actions. We reviewed pathology reports from 53 animals that stranded in the eastern Pacific Ocean and Hawaii between 2004 and 2013 and used data from 35 animals that stranded from 2001 to 2017 to assess association with morphometrics, blubber thickness, body condition and cause of death. Of the 53 cases, cause of death was determined for 22 (42%) and nine additional animals demonstrated findings of significant importance for population health. Causes of calf mortalities included infectious disease, nutritional, and congenital malformations. Mortalities in sub-adults were due to trauma, malnutrition, and infectious disease and in adults due to bacterial infections, emaciation and blunt force trauma. Death related to human interaction was found in every age class. Important incidental findings included concurrent sarcocystosis and toxoplasmosis, uterine leiomyoma, vertebral periosteal proliferations, cookiecutter shark (Isistius sp.) bite wounds, excessive tooth wear and an ingested fish hook. Blubber thickness increased significantly with body length (all p < 0.001). In contrast, there was no relationship between body length and an index of body condition (BCI). BCI was higher in animals that died from trauma. This study establishes a baseline for understanding health, nutritional status and causes of mortality in stranded killer whales. Given the evidence of direct human interactions on all age classes, in order to be most successful recovery efforts should address the threat of human interactions, especially for small endangered groups of killer whales that occur in close proximity to large human populations, interact with recreational and commercial fishers and transit established shipping lanes.

Seventy mortalities of North Atlantic right whales Eubalaena glacialis (NARW) were documented between 2003 and 2018 from Florida, USA, to the Gulf of St. Lawrence, Canada. These included 29 adults, 14 juveniles, 10 calves, and 17 of unknown age class. Females represented 65.5% (19/29) of known-sex adults. Fourteen cases had photos only; 56 carcasses received external examinations, 44 of which were also necropsied. Cause of death was determined in 43 cases, of which 38 (88.4%) were due to anthropogenic trauma: 22 (57.9%) from entanglement, and 16 (42.1%) from vessel strike. Gross and histopathologic lesions associated with entanglement were often severe and included deep lacerations caused by constricting line wraps around the flippers, flukes, and head/mouth; baleen plate mutilation; chronic extensive bone lesions from impinging line, and traumatic scoliosis resulting in compromised mobility in a calf. Chronically entangled whales were often in poor body condition and had increased cyamid burden, reflecting compromised health. Vessel strike blunt force injuries included skull and vertebral fractures, blubber and muscle contusions, and large blood clots. Propeller-induced wounds often caused extensive damage to blubber, muscle, viscera, and bone. Overall prevalence of NARW entanglement mortalities increased from 21% (1970-2002) to 51% during this study period. This demonstrates that despite mitigation efforts, entanglements and vessel strikes continue to inflict profound physical trauma and suffering on individual NARWs. These cumulative mortalities are also unsustainable at the population level, so urgent and aggressive intervention is needed to end anthropogenic mortality in this critically endangered species.

Small cetaceans continue to be exposed to elevated levels of persistent organic pollutants (POPs). The goals of this study were to use data from remote biopsy sampling and photographic-identification to compare POP concentrations between small cetacean stocks in the northern Gulf of Mexico. During 2015–2017, 74 remote biopsies were collected in St. Andrew Bay and adjacent coastal waters from two species: common bottlenose dolphin (Tursiops truncatus) (N = 28, ♀; N = 42, ♂) and Atlantic spotted dolphin (Stenella frontalis) (N = 2, ♀; N = 2, ♂). Common bottlenose dolphin POP concentrations were significantly higher in St. Andrew Bay than coastal waters. Male St. Andrew Bay dolphins had the highest Σ DDT (dichlorodiphenyl-dichloroethane) levels measured in the southeastern U.S. (67 μg/g, 50–89 μg/g; geometric mean and 95% CI) and showed a significant negative relationship between Σ DDT and sighting distance from a St. Andrew Bay point source.

The Deepwater Horizon (DWH) incident was the largest offshore oil spill in the history of the United States, contaminating surface waters, the water column, deep-sea corals and benthos, nearshore and coastal ecosystems, and natural resources across 5 states and an ocean area of more than 112000 km2 in the Gulf of Mexico (GoM). Protected marine speciesósea turtles and marine mammals, in particularówere a main focus of the DWH Natural Resource Damage Assessment (NRDA). The DWH spill overlapped in time and space with sea turtle and marine mammal habitats and life stages throughout the northern GoM. Thus, the DWH NRDA Trustees (2016; www.gulfspillrestoration.noaa.gov/restoration-planning/gulf-plan/) performed several activities to assess adverse effects of oil exposure on sea turtles and marine mammals to quantify the full extent and nature of the impacts to these taxa across the region. A synopsis of the Trusteesí assessment activities and conclusions is presented in the DWH NRDA Programmatic Damage Assessment and Restoration Plan (DWH NRDA Trustees 2016). This Theme Section presents several of these specific sea turtle and marine mammal assessment activities and associated findings. This Overview provides a context for the Theme Section papers, introduces basic NRDA concepts and discusses generally why and how protected marine species were assessed in the DWH NRDA.

Common bottlenose dolphins Tursiops truncatus were present in Barataria Bay, Louisiana, USA, before, during, and after the 2010 Deepwater Horizon oil spill. Health assessments conducted on dolphins in Barataria Bay in 2011, 2013, and 2014, after the capping of the well, found disease conditions consistent with petroleum hydrocarbon exposure and toxicity. Satellite-linked transmitters were affixed to dolphins during these health assessments for assessing the potential for continued exposure to petroleum-associated products, estimating survival rates, and planning potential restoration. In total, 44 tags were deployed, transmitting for 48 to 260 d. The dolphins exhibited multi-year site fidelity to small home ranges. Most tagged dolphin locations were inside the bay. On average, the dolphins that entered the Gulf coastal waters remained within 1.75 km of shore. No dolphins were documented more than 14 km beyond their 95% utilization distribution (UD) overall home ranges. Individual variation in the use of specific regions and habitats of Barataria Bay suggests the occurrence of community structure. All but 3 of the dolphins (93%) were tracked or observed during more than 1 yr in Barataria Bay, with 20 (45%) recorded each year from 2010 to 2014. All but 6 dolphins (86%) were tracked during multiple seasons. Home range sizes were comparable to those reported for bottlenose dolphins elsewhere. These findings suggest the occurrence of long-term, year-round residency. Residency patterns suggest potential for continued exposure to petroleum-associated products that may have remained in Barataria Bay after the spill.

Field studies documented increased mortality, adverse health effects, and reproductive failure in common bottlenose dolphins Tursiops truncatus following the Deepwater Horizon (DWH) oil spill. In order to determine the appropriate type and amount of restoration needed to compensate for losses, the overall extent of injuries to dolphins had to be quantified. Simply counting dead individuals does not consider long-term impacts to populations, such as the loss of future reproductive potential from mortality of females, or the chronic health effects that continue to compromise survival long after acute effects subside. Therefore, we constructed a sex- and agestructured model of population growth and included additional class structure to represent dolphins exposed and unexposed to DWH oil. The model was applied for multiple stocks to predict injured population trajectories using estimates of post-spill survival and reproductive rates. Injured trajectories were compared to baseline trajectories that were expected had the DWH incident not occurred. Two principal measures of injury were computed: (1) lost cetacean years (LCY); the difference between baseline and injured population size, summed over the modeled time period, and (2) time to recovery; the number of years for the stock to recover to within 95% of baseline. For the dolphin stock in Barataria Bay, Louisiana, the estimated LCY was substantial: 30 347 LCY (95% CI: 11 511 to 89 746). Estimated time to recovery was 39 yr (95% CI: 24 to 80). Similar recovery timelines were predicted for stocks in the Mississippi River Delta, Mississippi Sound, Mobile Bay and the Northern Coastal Stock. Publisher PDF

The potential role of morbillivirus was evaluated in the deaths of >1100 bottlenose dolphins Tursiops truncatus and other small cetaceans that stranded from February 2010 through July 2014, during the northern Gulf of Mexico (GoM) unusual mortality event (UME). Morbillivirus analysis was carried out on 142 live or freshly dead cetaceans and results were combined with samples from 102 live, free-ranging bottlenose dolphins sampled during capture-release health assessments conducted from 2011 to 2014. Polymerase chain reaction (PCR) testing for morbillivirus showed that 9.9% (14/142) of the stranded cetaceans and 1% (1/83) of the free-ranging live dolphins were positive for dolphin morbilliviral (DMV) RNA. In contrast, previous DMV dolphin die-offs had DMV detectable by PCR in 61 to 97% of animals tested. Histologic findings consistent with morbillivirus infection, including lymphoid depletion, bronchointerstitial pneumonia, syncytial cell formation, or meningoencephalitis, were found in 6.6% (9/136) of the cetaceans that underwent histologic examinations. Serological analysis using a virus neutralization assay found that 29% (5/17) of live stranded and 23% (23/102) of live free-ranging bottlenose dolphins had titers of 64 or greater for cetacean morbillivirus, indicating prior but not necessarily recent exposure to morbillivirus. Current findings suggest that DMV infection, although present in the northern GoM, was sporadic and occurred at low levels and therefore was not the primary cause of the northern GoM UME. Confirmation of DMV infections and existing DMV titers demonstrate continued exposure to morbillivirus among northern GoM cetaceans since the first detection of this virus in the early 1990s.

The 2010 Deepwater Horizon (DWH) disaster resulted in large-scale oil contamination of the northern Gulf of Mexico. As part of the Natural Resource Damage Assessment designed to investigate the potential impacts of the DWH oil spill, comprehensive health assessments were conducted on bottlenose dolphins Tursiops truncatus living in oiled bays (Barataria Bay [BB], Louisiana, and Mississippi Sound [MS], Mississippi/Alabama) and a reference bay with no evidence of DWH oil contamination (Sarasota Bay [SB], Florida). As previously reported, multiple health issues were detected in BB dolphins during 2011. In the present study, follow-on capture-release health assessments of BB dolphins were performed (2013, 2014) and indicated an overall improvement in population health, but demonstrated that pulmonary abnormalities and impaired stress response persisted for at least 4 yr after the DWH disaster. Specifically, moderate to severe lung disease remained elevated, and BB dolphins continued to release low levels of cortisol in the face of capture stress. The proportion of guarded or worse prognoses in BB improved over time, but 4 yr post-spill, they were still above the proportion seen in SB. Health assessments performed in MS in 2013 showed similar findings to BB, characterized by an elevated prevalence of low serum cortisol and moderate to severe lung disease. Prognosis scores for dolphins examined in MS in 2013 were similar to BB in 2013. Data from these follow-on studies confirmed that dolphins living in areas affected by the DWH spill were more likely to be ill; however, some improvement in population health has occurred over time.

Tursiops truncatus (Common Bottlenose Dolphin) in Georgia are exposed to multiple natural and anthropogenic stressors. Here, we describe a case study of an adult, male Common Bottlenose Dolphin entangled in marine debris, that was temporarily captured, disentangled, sampled for health assessment, satellite tagged, and released. Photographic-identification history and short-term tagging data support that the animal, Z58, has long-term site fidelity to the estuaries of southern Georgia. Health-assessment results identified several abnormal health parameters, including anemia, which likely resulted from exposure to extremely high site-specific contaminants that are known in the area. This note provides a case study of the various stressors to which Common Bottlenose Dolphins in Georgia are exposed, which can be used to develop effective management strategies for at-risk populations.

In 2017 an emergency field effort was undertaken in an attempt to prevent the extinction of the world's most endangered marine mammal, the vaquita Phocoena sinus. The rescue effort involved 90 experts from 9 countries and cost US$ 5 million. Following a long decline due to entanglement in legal gillnet fisheries, the vaquita population had fallen from more than 200 to fewer than 30 individuals from 2008 to 2016, due to entanglement in an illegal gillnet fishery that supplies swim bladders of the endangered totoaba Totoaba macdonaldi to Chinese black markets. An emergency ban of gillnets and increased enforcement failed to slow the decline, triggering an emergency effort to catch vaquitas and place them under protection in captivity. Two animals were targeted and captured using light gill nets; a juvenile was released 4 h later because it appeared stressed, and an adult female died of capture myopathy. The program was suspended because of the risk of additional mortalities to the population. The lack of success in capturing vaquitas for temporary protection emphasizes the need to improve our understanding of the effects of chase, capture, handling and enclosure on cetaceans, and to consider intervention before populations reach critically low levels, when there is sufficient time to use phased, precautionary approaches. Furthermore, conservation approaches focused on single species must be integrated into broader efforts to conserve ecosystems and involve the human communities that depend on them.

Oil spills of unknown origin were detected in three oil-fouled, ice-associated seals from the Alaska Bering Strait region collected by Alaska Native subsistence hunters during fall 2012. Bile analyses of two oiled seals indicated exposure to fluorescent polycyclic aromatic hydrocarbon (PAH) metabolites but levels of some metabolites were similar to or lower than biliary levels in harvested unoiled ice seals. Oiled seals had elevated tissue PAH concentrations compared to tissue levels of PAHs determined in unoiled ice seals. However, regardless of oiling status, tissue PAH levels were relatively low (

Common bottlenose dolphins serve as sentinels for the health of their coastal environments as they are susceptible to health impacts from anthropogenic inputs through both direct exposure and food web magnification. Remote biopsy samples have been widely used to reveal contaminant burdens in free-ranging bottlenose dolphins, but do not address the health consequences of this exposure. To gain insight into whether remote biopsies can also identify health impacts associated with contaminant burdens, we employed RNA sequencing (RNA-seq) to interrogate the transcriptomes of remote skin biopsies from 116 bottlenose dolphins from the northern Gulf of Mexico and southeastern U.S. Atlantic coasts. Gene expression was analyzed using principal component analysis, differential expression testing, and gene co-expression networks, and the results correlated to season, location, and contaminant burden. Season had a significant impact, with over 60% of genes differentially expressed between spring/summer and winter months. Geographic location exhibited lesser effects on the transcriptome, with 23.5% of genes differentially expressed between the northern Gulf of Mexico and the southeastern U.S. Atlantic locations. Despite a large overlap between the seasonal and geographical gene sets, the pathways altered in the observed gene expression profiles were somewhat distinct. Co-regulated gene modules and differential expression analysis both identified epidermal development and cellular architecture pathways to be expressed at lower levels in animals from the northern Gulf of Mexico. Although contaminant burdens measured were not significantly different between regions, some correlation with contaminant loads in individuals was observed among co-expressed gene modules, but these did not include classical detoxification pathways. Instead, this study identified other, possibly downstream pathways, including those involved in cellular architecture, immune response, and oxidative stress, that may prove to be contaminant responsive markers in bottlenose dolphin skin.

Health assessments of wild cetaceans can be challenging due to the difficulty of gaining access to conventional diagnostic matrices of blood, serum and others. While the noninvasive detection of metabolites in exhaled breath could potentially help to address this problem, there exists a knowledge gap regarding associations between known disease states and breath metabolite profiles in cetaceans. This technology was applied to the largest marine oil spill in U.S. history (The 2010 Deepwater Horizon oil spill in the Gulf of Mexico). An accurate analysis was performed to test for associations between the exhaled breath metabolome and sonographic lung abnormalities as well as hematological, serum biochemical, and endocrine hormone parameters. Importantly, metabolites consistent with chronic inflammation, such as products of lung epithelial cellular breakdown and arachidonic acid cascade metabolites were associated with sonographic evidence of lung consolidation. Exhaled breath condensate (EBC) metabolite profiles also correlated with serum hormone concentrations (cortisol and aldosterone), hepatobiliary enzyme levels, white blood cell counts, and iron homeostasis. The correlations among breath metabolites and conventional health measures suggest potential application of breath sampling for remotely assessing health of wild cetaceans. This methodology may hold promise for large cetaceans in the wild for which routine collection of blood and respiratory anomalies are not currently feasible.

This work was supported by funding from the International Whaling Commission's Pollution 2000+Program, the U.S. NOAA/NFMS Health and Stranding Response Program and the UK's Natural Environment Research Council (Grant Code SMRU 10001). The potential impact of exposure to polychlorinated biphenyls (PCBs) on the health and survival of cetaceans continues to be an issue for conservation and management, yet few quantitative approaches for estimating population level effects have been developed. An individual based model (IBM) for assessing effects on both calf survival and immunity was developed and tested. Three case study species (bottlenose dolphin, humpback whale and killer whale) in four populations were taken as examples and the impact of varying levels of PCB uptake on achievable population growth was assessed. The unique aspect of the model is its ability to evaluate likely effects of immunosuppression in addition to calf survival, enabling consequences of PCB exposure on immune function on all age-classes to be explored. By incorporating quantitative tissue concentration-response functions from laboratory animal model species into an IBM framework, population trajectories were generated. Model outputs included estimated concentrations of PCBs in the blubber of females by age, which were then compared to published empirical data. Achievable population growth rates were more affected by the inclusion of effects of PCBs on immunity than on calf survival, but the magnitude depended on the virulence of any subsequent encounter with a pathogen and the proportion of the population exposed. Since the starting population parameters were from historic studies, which may already be impacted by PCBs, the results should be interpreted on a relative rather than an absolute basis. The framework will assist in providing quantitative risk assessments for populations of concern. Postprint Postprint

Blubber has been proposed as a possible alternative to blood in the assessment of endocrine physiology in marine mammals because it can be collected via remote biopsy, which removes some of the confounding variables and logistical constraints associated with blood collection. To date, few studies have directly assessed the relationships between circulating versus blubber steroid hormone profiles in marine mammals, and these studies have been limited to a small subset of steroid hormones, which collectively limit the current utility of blubber steroid hormone measurements. In this study, we used liquid-chromatography tandem-mass spectrometry (LC-MS/MS) to screen for 16 steroid hormones in matched blood and blubber samples from free-ranging common bottlenose dolphins (Tursiops truncatus). Seven steroid hormones were detected and quantified, including two progestogens, two androgens, and three corticosteroids. Using principal components analysis (PCA), we explored relationships between hormones in both matrices and three physiological states: sexual maturity, pregnancy, and acute stress response. Plasma and blubber testosterone and its precursors, 17-hydroxyprogesterone and androstenedione, loaded to the first principal component (PC1), and PC1 scores were higher in mature males. Plasma and blubber progesterone loaded to PC2, and pregnant/probable pregnant females had significantly higher PC2 scores. Pregnant females also had higher PC1 scores than other females, suggesting differences in androgen profiles between these groups. There was disagreement between plasma and blubber corticosteroid profiles, as indicated by their loading to different PCs; plasma corticosteroids loaded to PC3 and blubber corticosteroids to PC4. PC3 scores were significantly predicted by elapsed time to blood collection (i.e., time between initiating the capture process and blood collection), while elapsed time to blubber collection significantly predicted PC4 scores, indicating that corticosteroid profiles shift in both tissues during acute stress. Corticosteroid profiles were not related to demographic group, site-month, body mass index, water temperature, or time spent outside of the water on the processing boat. Overall, these results demonstrate that blubber steroid hormone profiles reflect changes in endocrine function that occur over broad temporal scales.

Hundreds of southern right whale calves Eubalaena australis died on their calving ground at Peninsula Valdes, Argentina from 2003 through 2011. During this period, the number of dead calves increased at a much greater rate than that of living calves over the preceding 32 yr, and with greater inter-annual variation. High mortality events occurred late in the calving seasons of 2005 and 2007, early in the seasons of 2008 and 2009, and were equally divided between early and late in 2010 and 2011. Calves that died late in the seasons of 2005 and 2007 were at least a meter longer (mean 7.3 m) than newborns, indicating that they had grown and presumably were healthy before dying. An unusual number of large calves (>6 m) died early in the seasons of 2008 and 2009, suggesting that a population-wide process (e.g. nutritional stress) affected many mothers including older, larger mothers that tend to give birth to larger calves early in the season. Many tissue samples have been collected and analyzed, but no consistent lesions, pathologic processes or elevated levels of algal biotoxins have been identified to explain these recent mortality events. Here, we document the high mortality events, place them in historical context and describe ongoing efforts to identify their causes. As of 2010, the southern right whale sub-population that calves off Peninsula Valdes was estimated to be less than 20% of its initial size before whaling; the ongoing high mortality of calves will significantly affect its recovery.

Electronic tags have proven to be valuable tools in assessing small cetacean movement and behavior. However, problems associated with tag size and attachment have limited duration and damaged dorsal fins. These outcomes have motivated researchers to develop a new satellite-linked tag design that reduces detrimental effects to tagged animals, while increasing transmission durations. The goals of this study were to review previous studies that deployed single-pin transmitters and determine factors that influence transmission duration. Then, test these factors utilizing computational fluid dynamics (CFD) models to identify an optimal single-pin satellite-linked tag design, and evaluate this prototype through field studies. A review of four projects, which deployed 77 single-pin radio tags, determined that tags attached along the lower third of the dorsal fin and approximately 33 mm from the trailing edge resulted in longer transmission durations and reduced negative impacts to the dorsal fin. Based upon these results and CFD modeling, prototype, single-pin satellite-linked tags (n = 25) transmitted for 163 ± 22 d (mean ± 95% CI) which greatly exceeded transmissions for previous small cetacean telemetry studies. These results suggest that the newly developed single-pin satellite-linked tag design strikes a balance between reducing impacts to the individual while maximizing transmissions.

Firestorms negatively affected air quality throughout San Diego County during 2003 and 2007, including the San Diego Bay, which houses the Navy's bottlenose dolphins (Tursiops truncatus).To assess the potential impact of the 2003 and 2007 fires on dolphin health.Hematology and serum chemistry values were evaluated retrospectively among Navy dolphins the year and month before; during; and the month after the 2003 and 2007 fires.Both 2003 and 2007 fires were associated with lower calcium either during or the month post-fire compared to the control periods. During and the month following the 2003 fire, dolphins had higher serum carbon dioxide compared to the control periods. Dolphins during and the month following the 2007 fire had lower absolute or percent neutrophils and higher chloride. The 2007 fire was also associated with increased percent eosinophils during the fire and higher percent monocytes and bilirubin the month following the fire compared to the control periods.Consistent with what has been previously reported in humans and other animals, this study supports that fire smoke inhalation may have mild effects on dolphin physiology, including calcium homeostasis, lung function and immune response.

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

Decompression sickness (DCS; ‘the bends’) is a disease associated with gas uptake at pressure. The basic pathology and cause are relatively well known to human divers. Breath-hold diving marine mammals were thought to be relatively immune to DCS owing to multiple anatomical, physiological and behavioural adaptations that reduce nitrogen gas (N2) loading during dives. However, recent observations have shown that gas bubbles may form and tissue injury may occur in marine mammals under certain circumstances. Gas kinetic models based on measured time-depth profiles further suggest the potential occurrence of high blood and tissue N2 tensions. We review evidence for gas-bubble incidence in marine mammal tissues and discuss the theory behind gas loading and bubble formation. We suggest that diving mammals vary their physiological responses according to multiple stressors, and that the perspective on marine mammal diving physiology should change from simply minimizing N2 loading to management of the N2 load. This suggests several avenues for further study, ranging from the effects of gas bubbles at molecular, cellular and organ function levels, to comparative studies relating the presence/absence of gas bubbles to diving behaviour. Technological advances in imaging and remote instrumentation are likely to advance this field in coming years. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Cetacean morbilliviruses (CeMV) are viruses that can cause mass mortalities among various odontocete species. In this study levels of “herd” immunity in cetaceans from the U.S. coast are described from the distribution and prevalence of antibodies against morbilliviruses. Neutralizing antibody titers against dolphin morbillivirus (DMV), porpoise morbillivirus (PMV), phocine distemper (PDV), and canine distemper viruses (CDV) were measured. Positive samples had higher titers against the CeMV than against the other morbilliviruses tested, indicating that although PDV or CDV can be used to investigate exposure their use may result in a higher false negative rate. The results suggest that morbillivirus did not persist in coastal populations of bottlenose dolphins (Tursiops truncatus) after the major outbreaks that occurred in the 1980s and 1990s. Bottlenose dolphins from Beaufort, North Carolina; St. Joseph Bay, Florida; and Cape May, New Jersey had anti-DMV seroprevalences ranging from between 15% and 33% but those from Charleston, South Carolina and Sarasota Bay, Florida, sampled in recent years were largely negative. These latter groups are therefore now vulnerable to infection and could experience high mortality if exposed to CeMV. Sero-surveys of this kind are therefore vital for assessing the risk of new and recurring viral outbreaks in coastal cetaceans.

Biomonitoring surveys of wild cetaceans commonly utilize blubber as a means to assess exposure to persistent organic pollutants (POPs), but the relationship between concentrations in blubber and those in blood, a better indicator of target organ exposure, is poorly understood. To define this relationship, matched blubber and plasma samples (n = 56) were collected from free-ranging bottlenose dolphins (Tursiops truncatus) and analyzed for 61 polychlorinated biphenyl (PCB) congeners, 5 polybrominated diphenyl ether (PBDE) congeners, and 13 organochlorine pesticides (OCPs). With the exception of PCB 209, lipid-normalized concentrations of the major POPs in blubber and plasma were positively and significantly correlated (R(2) = 0.828 to 0.976). Plasma concentrations, however, significantly increased with declining blubber lipid content, suggesting that as lipid is utilized, POPs are mobilized into blood. Compound- and homologue- specific blubber/blood partition coefficients also differed according to lipid content, suggesting POPs are selectively mobilized from blubber. Overall, these results suggest that with the regression parameters derived here, blubber may be used to estimate blood concentrations and vice versa. Additionally, the mobilization of lipid from blubber and concomitant increase in contaminants in blood suggests cetaceans with reduced blubber lipid may be at greater risk for contaminant-associated health effects.

As apex predators within coastal ecosystems, bottlenose dolphins (Tursiops truncatus) are prone to accumulate complex mixtures of persistent organic pollutants (POPs). While substantial variations in POP patterns have been previously observed in dolphin populations separated across regional- and fine-scale geographic ranges, less is known regarding the factors influencing contaminant patterns within localized populations. To assess the variation of POP mixtures that occurs among individuals of a population, polychlorinated biphenyl (PCB), organochlorine pesticide (OCP) and polybrominated diphenyl ether (PBDE) concentrations were measured in blubber and milk of bottlenose dolphins resident to Sarasota Bay, FL, and principal components analysis (PCA) was used to explain mixture variations in relation to age, sex and reproductive maturity. PCA demonstrated significant variations in contaminant mixtures within the resident dolphin community. POP patterns in juvenile dolphins resembled patterns in milk, the primary diet source, and were dominated by lower-halogenated PCBs and PBDEs. A significant correlation between principal component 2 (PC2) and age in male dolphins indicated that juvenile contaminant patterns gradually shifted away from the milk-like pattern over time. Metabolically-refractory PCBs significantly increased with age in male dolphins, whereas PCBs subject to cytochrome p450 1A1 metabolism did not, suggesting that changes in male POP patterns likely resulted from the selective accumulation of persistent POP congeners. Changes to POP patterns were gradual for juvenile females, but changed dramatically at reproductive maturity and gradually shifted back towards pre-parturient profiles thereafter. Congener-specific blubber/milk partition coefficients indicated that lower-halogenated POPs were selectively offloaded into milk and changes in adult female contaminant profiles likely resulted from the offloading of these compounds during the first reproductive event and their gradual re-accumulation thereafter. Overall, these results indicate that significant variations in contaminant mixtures can exist within localized populations of bottlenose dolphins, with life history factors such as age and sex driving individual differences.

A mother and female calf humpback whale (Megaptera novaeangliae) pair were observed at an atypical location, 72 nmi inland in the Port of Sacramento, California, on 16 May 2007. Sequencing of mtDNA from a skin biopsy showed the cow to be an E1 haplotype, which is common in the California feeding population. Both animals had lacerations, suggesting sharp trauma from a boat strike. Photographs taken over 11 d showed generalized deterioration of skin condition and necrotic wound edges. Behavioral responses were recorded during attempts to move the animals downriver to the Pacific Ocean. The attempts included playback of alarm tones, humpback and killer whale sounds, banging hollow steel pipes (“Oikami pipes”), spraying water from fire hoses on the water surface, and utilizing tug and power boat engine noise and movement. None of these deterrents resulted in significant, consistent downstream movement by the whales. Antibiotic therapy (ceftiofur) was administered by a dart, representing the first reported antibiotic treatment of free-ranging live whales. After 11 d, the animals swam downstream from fresh water at Rio Vista to brackish water, and their skin condition noticeably improved 24 h later. The animals followed the deep-water channel through the Sacramento

Describing the viral diversity of wildlife can provide interesting and useful insights into the natural history of established human pathogens. In this study, we describe a previously unknown picornavirus in harbor seals (tentatively named phopivirus) that is related to human hepatitis A virus (HAV). We show that phopivirus shares several genetic and phenotypic characteristics with HAV, including phylogenetic relatedness across the genome, a specific and seemingly quiescent tropism for hepatocytes, structural conservation in a key functional region of the type III internal ribosomal entry site (IRES), and a codon usage bias consistent with that of HAV., IMPORTANCE Hepatitis A virus (HAV) is an important viral hepatitis in humans because of the substantial number of cases each year in regions with low socioeconomic status. The origin of HAV is unknown, and no nonprimate HAV-like viruses have been described. Here, we describe the discovery of an HAV-like virus in seals. This finding suggests that the diversity and evolutionary history of these viruses might be far greater than previously thought and may provide insight into the origin and pathogenicity of HAV.

Inshore common bottlenose dolphins (Tursiops truncatus) are exposed to a broad spectrum of natural and anthropogenic stressors. In response to these stressors, the mammalian adrenal gland releases hormones such as cortisol and aldosterone to maintain physiological and biochemical homeostasis. Consequently, adrenal gland dysfunction results in disruption of hormone secretion and an inappropriate stress response. Our objective herein was to develop diagnostic reference intervals (RIs) for adrenal hormones commonly associated with the stress response (i.e., cortisol, aldosterone) that account for the influence of intrinsic (e.g., age, sex) and extrinsic (e.g., time) factors. Ultimately, these reference intervals will be used to gauge an individual’s response to chase-capture stress and could indicate adrenal abnormalities. Linear mixed models (LMMs) were used to evaluate demographic and sampling factors contributing to differences in serum cortisol and aldosterone concentrations among bottlenose dolphins sampled in Sarasota Bay, Florida, USA (2000–2012). Serum cortisol concentrations were significantly associated with elapsed time from initial stimulation to sample collection (p

Perfluoroalkyl compounds (PFCs) were determined in plasma, milk, and urine of free-ranging bottlenose dolphins (Tursiops truncatus) from Sarasota Bay (FL, USA) during three winter and two summer capture-and-release programs (2002-2005). Plasma and urine samples were extracted using an ion-pairing method. Perfluoroalkyl compounds were extracted from milk samples using acetonitrile, and extracts were cleaned with graphitized nonporous carbon. All extracts were analyzed by high-performance liquid chromatography-tandem mass spectrometry. Mean seasonal sum of PFCs (sigma PFCs) detected in dolphin plasma ranged from 530 to 927 ng/g wet weight. No significant differences (p > 0.05) were found in concentrations between seasons, suggesting a constant exposure to PFCs. Overall, blubber thickness of dolphins did not correlate with PFC concentrations in plasma, suggesting an absence of PFC sequestration in blubber. Sexually immature calves (age

Research initiated in 1970 has identified a long-term, year-round resident community of about 140 bottlenose dolphins (Tursiops truncatus) in Sarasota Bay, Florida, providing unparalleled opportunities to investigate relationships between organochlorine contaminant residues and life-history and reproductive parameters. Many individual dolphins are identifiable and of known age, sex, and maternal lineage (or =4 generations). Observational monitoring provides data on dolphin spatial and temporal occurrence, births and fates of calves, and birth-order. Capture-release operations conducted for veterinary examinations provide biological data and samples for life-history and contaminant residue measurement. Organochlorine concentrations in blubber and blood (plasma) can be examined relative to age, sex, lipid content, and birth-order. Reproductive success is evaluated through tracking of individual female lifetime calving success. For the current study, 47 blubber samples collected during June 2000 and 2001 were analyzed for PCB concentrations of 22 congeners relative to life-history factors and reproductive success. Prior to sexual maturity, males and females exhibited similar concentrations of about 15-50 ppm. Classical patterns of accumulation with age were identified in males, but not in females. Subsequently, males accumulated higher concentrations of PCBs through their lives (100 ppm), whereas females begin to depurate with their first calf, reaching a balance between contaminant intake and lactational loss (15 ppm). In primiparous females, PCB concentrations in blubber and plasma and the rates of first-born calf mortality were both high. First-born calves had higher concentrations than subsequent calves of similar age (25 vs.25 ppm). Maternal burdens were lower early in lactation and increased as calves approached nutritional independence. Empirical data were generally consistent with a published theoretical risk assessment and supported the need for incorporation of threats from indirect anthropogenic impacts such as environmental pollutants into species management plans. Long-term observational monitoring and periodic biological sampling provide a powerful, non-lethal approach to understanding relationships between organochlorine residue concentrations in tissues and reproductive parameters for coastal dolphins.

Wild California sea lions (Zalophus californianus) have an unusually high prevalence of neoplasms (18% of stranded dead adults) and high levels of contaminants. The contribution of organochlorine (OC) tissue burdens to the probability of sea lions dying from carcinoma was explored using a logistic regression model. Levels of PCBs and DDTs were determined in blubber of sea lions diagnosed with metastatic carcinoma and animals that had died from non-carcinoma-related incidents (e.g., gunshot, domoic acid poisoning). Animals with carcinoma had higher mean concentrations (based on wet weight) of PCBs and DDTs (more than 85% and 30% higher, respectively) in blubber than did sea lions without carcinoma; the highest concentrations of OCs in the sea lions affected with carcinoma were measured in the males. Blubber thickness was significantly different between the two groups of sea lions, but after controlling for this difference, there was still a significant effect of PCBs, but not DDTs, on the probability of sea lions dying with carcinoma. Age, sex, mass and length did not affect the probability of dying from carcinoma.

Phocine herpesvirus-1 (PhHV-1) has been associated with morbidity and high mortality in neonatal harbor seals (Phoca vitulina) along the Pacific coast of California (USA) and in northern Europe. Seals dying with PhHV-1 associated disease in California primarily have histopathologic evidence of adrenal necrosis or adrenalitis with herpesviral inclusion bodies. Little is known about prevalence of exposure to PhHV-1, modes of disease transmission, and viral pathogenesis in free-ranging harbor seal populations. To evaluate the prevalence in North America, 866 serum samples collected between 1994 and 2002 from harbor seals captured or stranded on the Pacific and Atlantic coasts of North America were assayed by enzyme linked immunosorbent assay (ELISA) for evidence of PhHV-1 exposure. Samples from three harbor seal age classes (pre-weaned, weaned, and subadults/adults) were obtained from each of four regions to compare exposure among sex, age class, and region. We found increasing prevalence with age as 37.5% of pre-weaned pups, 87.6% of weaned pups, and 99.0% of subadults and adults were seropositive. When accounting for age, no associations between seropositivity and sex or location of harbor seals were detected. These data indicate that PhHV-1 is endemic in the harbor seal populations of North America.

A multi-year unusual mortality event (UME) involving primarily common bottlenose dolphins (Tursiops truncates) was declared in the northern Gulf of Mexico (GoM) with an initial start date of February 2010 and remains ongoing as of August 2014. To examine potential changing characteristics of the UME over time, we compared the number and demographics of dolphin strandings from January 2010 through June 2013 across the entire GoM as well as against baseline (1990-2009) GoM stranding patterns. Years 2010 and 2011 had the highest annual number of stranded dolphins since Louisiana’s record began, and 2011 was one of the years with the highest strandings for both Mississippi and Alabama. Statewide, annual numbers of stranded dolphins were not elevated for GoM coasts of Florida or Texas during the UME period. Demographic, spatial, and temporal clusters identified within this UME included increased strandings in northern coastal Louisiana and Mississippi (March-May 2010); Barataria Bay, Louisiana (August 2010-December 2011); Mississippi and Alabama (2011, including a high prevalence and number of stranded perinates); and multiple GoM states during early 2013. While the causes of the GoM UME have not been determined, the location and magnitude of dolphin strandings during and the year following the 2010 Deepwater Horizon oil spill, including the Barataria Bay cluster from August 2010 to December 2011, overlap in time and space with locations that received heavy and prolonged oiling. There are, however, multiple known causes of previous GoM dolphin UMEs, including brevetoxicosis and dolphin morbillivirus. Additionally, increased dolphin strandings occurred in northern Louisiana and Mississippi before the Deepwater Horizon oil spill. Identification of spatial, temporal, and demographic clusters within the UME suggest that this mortality event may involve different contributing factors varying by location, time, and bottlenose dolphin populations that will be better discerned by incorporating diagnostic information, including histopathology.

Lacazia loboi, a cutaneous fungus, is found in humans and dolphins from transitional tropical (Florida) and tropical (South America) regions. We report 2 cases of lobomycosis in stranded bottlenose dolphins (Tursiops truncatus) and 1 case of lobomycosis-like disease in 1 free-swimming, pelagic, offshore bottlenose dolphin from North Carolina, where no cases have previously been observed.

Contamination of coastal waters can carry pathogens and contaminants that cause diseases in humans and wildlife, and these pathogens can be transported by water to areas where they are not indigenous. Marine mammals may be indicators of potential health effects from such pathogens and toxins. Here we isolated bacterial species of relevance to humans from wild bottlenose dolphins Tursiops truncatus and assayed isolated bacteria for antibiotic resistance. Samples were collected during capture-release dolphin health assessments at multiple coastal and estuarine sites along the US mid-Atlantic coast and the Gulf of Mexico. These samples were transported on ice and evaluated using commercial systems and aerobic culture techniques routinely employed in clinical laboratories. The most common bacteria identified were species belonging to the genus Vibrio, although Escherichia coli, Shewanella putrefaciens, and Pseudomonas fluorescens/putida were also common. Some of the bacterial species identified have been associated with human illness, including a strain of methicillin-resistant Staphylococcus aureus (MRSA) identified in 1 sample. Widespread antibiotic resistance was observed among all sites, although the percentage of resistant isolates varied across sites and across time. These data provide a baseline for future comparisons of the bacteria that colonize bottlenose dolphins in the southeastern USA.