Killer whales (Orcinus orca) have been deemed one of the most contaminated cetacean species in the world. However, concentrations and potential health implications of selected ‘contaminants of ...emerging concern’ (CECs) and new persistent organic pollutants (POPs) in endangered Southern Resident and threatened Bigg’s (Transient) killer whales in the Northeastern Pacific (NEP) have not yet been documented. Here, we quantify CECs alkylphenols (APs), triclosan, methyl triclosan, and per- and polyfluoroalkyl substances (PFAS) and new POPs hexabromocyclododecane (HBCCD), PFOS, PFOA, and PFHxS in skeletal muscle and liver samples of these sentinel species and investigate in utero transfer of these contaminants. Samples were collected from necropsied individuals from 2006 to 2018 and analyzed by LC–MS/MS or HRBC/HRMS. AP and PFAS contaminants were the most prevalent compounds; 4-nonylphenol (4NP) was the predominant AP (median 40.84 ng/g ww), and interestingly, 7:3-fluorotelomer carboxylic acid (7:3 FTCA) was the primary PFAS (median 66.35 ng/g ww). Maternal transfer ratios indicated 4NP as the most transferred contaminant from the dam to the fetus, with maternal transfer rates as high as 95.1%. Although too few killer whales have been screened for CECs and new POPs to infer the magnitude of contamination impact, these results raise concerns regarding pathological implications and potential impacts on fetal development and production of a viable neonate. This study outlines CEC and new POP concentrations in killer whales of the NEP and provides scientifically derived evidence to support and inform regulation to mitigate pollutant sources and contamination of Southern Resident killer whale critical habitat and other marine ecosystems.
Effective 'valving' in the upper aerodigestive tract (UAT) is essential to temporarily separate the digestive and respiratory pathways. Marine mammals are largely dedicated to feeding underwater, and ...in many cases swallowing prey whole. In seals, little work has been done to explore the anatomy and function of the UAT in the context of valving mechanisms that function to separate food and air pathways. Here we use videofluoroscopy, gross dissection, histology and computed tomography (CT) renderings to explore the anatomy of the larynx and soft palate in the harbour seal (
), and generate models for how valving mechanisms in the head and neck may function during breathing, phonating, diving and swallowing. Harbour seals have an elevated larynx and the epiglottis may rise above the level of the soft palate, particularly in pups when sucking. In addition, the corniculate and arytenoid cartilages with associated muscles form most of the lateral margins of the laryngeal inlet and vestibule, and move independently to facilitate airway closure. The corniculate cartilages flex over the laryngeal inlet beneath the epiglottis to completely close the laryngeal vestibule and inlet. The vocal folds are thick and muscular and the medial margin of the folds contains a small vocal ligament. The soft palate has well-defined levator veli palatini muscles that probably function to elevate the palate and close the pharyngeal isthmus during feeding. Our results support the conclusion that harbour seals have evolved UAT valving mechanisms as adaptations to a marine environment that are not seen in terrestrial carnivores.
Abstract only
In North America, wild harbor seal neonates and pups (
Phoca vitulina
) are among the most common marine mammals admitted to rescue centers. Nutritional support is typically via gavage ...as most are admitted prior to weaning. In order to advance seal feeding and swallowing rehabilitation, we require a comprehensive understanding of their upper aerodigestive tract (UAT) as it applies to swallowing physiology. Anatomical studies of the harbor seal UAT are limited, and standardized UAT measurements for neonates and pups have not yet been determined. Our objective is to design a systematic method to measure their UAT structures and then obtain quantitative values. During post mortem examination, we photographed UAT structures using scalars. Structures included: tongue, vocal folds, cricoid cartilage, trachea, and epiglottis.
A priori
, we developed a manual outlining measurement start and endpoints using ImageJ (NIH, 2010). Following measurements, we summarized results with means (standard deviations, SD) and medians (interquartile ranges, IQR) as appropriate and explored correlations (Pearson’s correlation coefficient, one‐tailed) between UAT structures and other body measurements. We used IBM SPSS analytical software version 26 (IBM Corporation, 2019) for analyses with significance of p<.05. Our specimens included 14 deceased harbor seal neonates or pups (9 males, 5 females) aged between three days and 2 months old at the time of death. Causes of death were either: spontaneous, congenital, or due to infectious, metabolic or malnutrition disorders, or by euthanasia after a humane endpoint was reached. On admission to rehabilitation, body measurement ranges included: 46.0 to 57.0 (body length cm), 36.0 to 59.0 (axillary girth cm) 5.8 to 12.6 (weight kg). Post‐mortem UAT measurements (mm, mean ± SD) included: 1) tongue tip to epiglottis base: 82.7 ± 6.9, 2) vocal fold length: 13.9 ± 2.0, 3) tracheal diameter: 10.3 ± 1.4, and 4) epiglottic length: 20.0 ± 2.8. Correlations between seal body length and UAT dimensions were not statistically significant. In conclusion, we have developed a systematic method to measure harbor seal neonate and pup UAT structures. To the best of our knowledge, these measurements, as they relate to swallowing, have not been previously reported. These findings expand the seal macroscopic anatomy knowledge base and contribute to cross‐species conceptual convergences between human and seal swallowing physiology and its rehabilitation.
Support or Funding Information
Supported by a UBC Faculty of Medicine Summer Student Research Program 2019 award to Hirad Nourbakhsh, UBC Faculty of Medicine Start‐up grant to Stacey A. Skoretz and by a Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant to A. Wayne Vogl (RGPIN‐2018‐03727).
Previously, we reported the isolation of Bartonella henselae from the blood of harbor porpoises (Phocoena phocoena) and loggerhead sea turtles (Caretta caretta) from the North Carolina coast. ...Hematologic, pathologic, and microbiologic findings surrounding the death of a juvenile captive beluga in Vancouver initiated an outbreak investigation designed to define the molecular prevalence of Bartonella infection in belugas. Using polymerase chain reaction analyses targeting the intergenic spacer region (ITS), two B. henselae ITS strains were identified in 78% of captive and free-ranging hunter-harvested belugas. These findings may have public health implications and may influence aquarium management procedures for captive marine mammals.
Whaling has decimated North Atlantic right whales Eubalaena glacialis (NARW) since the 11th century and southern right whales E. australis (SRW) since the 19th century. Today, NARWs are Critically ...Endangered and decreasing, whereas SRWs are recovering. We review NARW health assessment literature, NARW Consortium databases, and efforts and limitations to monitor individual and species health, survival, and fecundity. Photographs are used to track individual movement and external signs of health such as evidence of vessel and entanglement trauma. Post-mortem examinations establish cause of death and determine organ pathology. Photogrammetry is used to assess growth rates and body condition. Samples of blow, skin, blubber, baleen and feces quantify hormones that provide information on stress, reproduction, and nutrition, identify microbiome changes, and assess evidence of infection. We also discuss models of the population consequences of multiple stressors, including the connection between human activities (e.g. entanglement) and health. Lethal and sublethal vessel and entanglement trauma have been identified as major threats to the species. There is a clear and immediate need for expanding trauma reduction measures. Beyond these major concerns, further study is needed to evaluate the impact of other stressors, such as pathogens, microbiome changes, and algal and industrial toxins, on NARW reproductive success and health. Current and new health assessment tools should be developed and used to monitor the effectiveness of management measures and will help determine whether they are sufficient for a substantive species recovery.
Abandoned harbor seal pups (Phoca vitulina) are frequently recovered by rehabilitation centers and often require intensive nursing, gavage feeding and swallowing rehabilitation prior to anticipated ...release. Seal upper aerodigestive tract (UAT) histology descriptions relevant to deglutition are limited, impacting advances in rehabilitation practice. Therefore, we examined the histological characteristics of the harbor seal UAT to understand species‐specific functional anatomy and characterize adaptations. To this end, we conducted gross dissections, compiled measurements and reviewed histologic features of the UAT structures of 14 preweaned harbor seal pups that died due to natural causes or were humanely euthanized. Representative samples for histologic evaluation included the tongue, salivary glands, epiglottis, and varying levels of the trachea and esophagus. Histologically, there was a prominent muscularis in the tongue with fewer lingual papillae types compared to humans. Abundant submucosal glands were observed in lateral and pharyngeal parts of the tongue and rostral parts of the esophagus. When compared to other mammalian species, there was a disproportionate increase in the amount of striated muscle throughout the length of the esophageal muscularis externa. This may indicate a lesser degree of autonomic control over the esophageal phase of swallowing in harbor seals. Our study represents the first detailed UAT histological descriptions for neonatal harbor seals. Collectively, these findings support specific anatomic and biomechanical adaptations relevant to suckling, prehension, and deglutition. This work will inform rehabilitation practices and guide future studies on swallowing physiology in harbor seals with potential applications to other pinniped and otariid species in rehabilitation settings.
From February to May 2021, four nonmigratory rams from the Radium-Stoddart bighorn sheep (BHS; Ovis canadensis) herd in the Rocky Mountains of southeastern British Columbia, Canada, died from ...infection with the giant liver fluke, Fascioloides magna. Affected animals were emaciated, weak, and lethargic or were found dead. Gross lesions, histopathology, and parasite burdens were consistent with those reported in experimentally infected BHS, domestic sheep, and other aberrant hosts. Although BHS range does not typically overlap with fluke-contaminated aquatic habitats, the change in migratory behavior recently observed in some Radium-Stoddart rams may have exposed the affected animals to F. magna. We describe clinical signs and gross and histopathologic findings of hepatobiliary trematodiasis associated with F. magna in free-ranging BHS. From experimental data and our findings, giant liver fluke is pathogenic and is a threat to the conservation of the Radium-Stoddart BHS herd and other BHS herds in endemic F. magna regions.
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