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validation of a homologous canine relaxin radioimmunoassay and application with pregnant and non-pregnant northern fur seals (callorhinus ursinus).the primary objectives of this study were to validate a canine relaxin ria for use in otariids and phocids and consider practical applications. for 6 captive northern fur seal females, serum samples were grouped and examined according to pregnancy (n=13), post-partum (n=8) and non-pregnancy (n=6), and, for 2 captive northern fur seal males, serum samples were grouped and examined together regardless of age (2 mo-15 yrs, n=6). placental tissue was available for examination from one northern fur s ...201019501094
characterization of phylogenetically diverse astroviruses of marine mammals.astroviruses are small, non-enveloped, positive-stranded rna viruses. previously studied mammalian astroviruses have been associated with diarrhoeal disease. knowledge of astrovirus diversity is very limited, with only six officially recognized astrovirus species from mammalian hosts and, in addition, one human and some bat astroviruses were recently described. we used consensus pcr techniques for initial identification of five astroviruses of marine mammals: three from california sea lions (zal ...201019759240
expression and self-assembly of virus-like particles from two genotypes of marine vesiviruses and development of an elisa for the detection of antibodies.sequences encoding the major and minor capsid proteins (vp1 and vp2) from two marine vesivirus isolates (steller sea lion viruses v810 and v1415) were engineered for expression of virus-like particles (vlps) in the baculovirus system. the resulting vlps were morphologically similar to native vesivirus virions. purified vlps were probed in immunoblots with pooled antisera specific for nine san miguel sea lion virus (smsv) types, and a predominant protein of approximately 60kda was detected. an en ...201019913368
fecal triiodothyronine and thyroxine concentrations change in response to thyroid stimulation in steller sea lions (eumetopias jubatus).variation in concentrations of thyroid hormones shed in feces may help to identify physiological states of animals, but the efficacy of the technique needs to be validated for each species. we determined whether a known physiological alteration to thyroid hormone production was reflected in hormone concentrations in the feces of steller sea lions (eumetopias jubatus). we quantified variation of triiodothyronine (t3) and thyroxine (t4) concentrations in feces following two intramuscular injection ...201019941866
the cytotoxicity and genotoxicity of hexavalent chromium in steller sea lion lung fibroblasts compared to human lung fibroblasts.in this study we directly compared soluble and particulate chromate cytotoxicity and genotoxicity in human (homo sapiens) and sea lion (eumetopias jubatus) lung fibroblasts. our results show that hexavalent chromium induces increased cell death and chromosome damage in both human and sea lion cells with increasing intracellular chromium ion levels. the data further indicate that both sodium chromate and lead chromate are less cytotoxic and genotoxic to sea lion cells than human cells, based on a ...201020211760
non-invasive measurement of thyroid hormone in feces of a diverse array of avian and mammalian species.we developed and validated a non-invasive thyroid hormone measure in feces of a diverse array of birds and mammals. an i(131) radiolabel ingestion study in domestic dogs coupled with high pressure liquid chromatography (hplc) analysis, showed that peak excretion in feces occurred at 24-48h post-ingestion, with i(131)-labelled thyroid hormone metabolites excreted primarily as triiodothyronine (t3) and relatively little thyroxine (t4), at all excretion times examined. the immunoreactive t3 profile ...201020412809
coxiella burnetii infection of a steller sea lion (eumetopias jubatus) found in washington state.a pregnant sea lion stranded in the state of washington was found to have placentitis caused by a unique strain of coxiella burnetii. this is the first description of coxiellosis in a sea lion and suggests that exposure to sea lions may be a risk factor for contracting q fever.201020592144
characterization of progressive keratitis in otariids.to characterize a form of progressive keratitis that occurs commonly in otariids.201020840090
the effects of age, sex, season and geographic region on circulating serum cortisol concentrations in threatened and endangered steller sea lions (eumetopias jubatus).the role of stress in the decline of steller sea lions has become of interest in the identification of factors leading to their drastic decline and subsequent failure to recover. serum cortisol was validated as a potential indicator of stress in three sub-populations inhabiting the majority of the steller sea lions range (n=941). additionally, seasonal variability in serum cortisol measured in captive animals (n=9) of different age classes and sex was investigated. significant interactions were ...201019524580
steller sea lion (eumetopias jubatus) pups undergo a decrease in circulating white blood cells and the ability of t cells to proliferate during early postnatal development.postnatal changes in circulating immune components and peripheral blood mononuclear cell (pbmc) proliferation were assessed in steller sea lion pups (ssl; eumetopias jubatus). blood samples were collected for complete blood cell counts including total and differential white blood cell (wbc) counts from 46 pups ranging in age from 5 to 38 days old. total wbc and neutrophil counts decreased in association with increased age of the pups. the ability of pbmc to proliferate was assessed by in vitro e ...201020816245
psychophysical and electrophysiological aerial audiograms of a steller sea lion (eumetopias jubatus).a within-subject comparison of auditory steady-state response (assr) and psychophysical measurements of aerial hearing sensitivity was conducted with an individual of the largest otariid species, the steller sea lion. psychophysical methods were used to obtain an unmasked aerial audiogram at 13 frequencies, spanning a range of 0.125-34 khz. the subject had a hearing range (frequencies audible at 60 db(rms) re 20 micropa) of about 0.250-30 khz, and a region of best hearing sensitivity from 5-14.1 ...201020370049
complete mitochondrial genome of a steller sea lion eumetopias jubatus (carnivora, otariidae). 201020331329
seasonal influence on the response of the somatotropic axis to nutrient restriction and re-alimentation in captive steller sea lions (eumetopias jubatus).fluctuations in availability of prey resources can impede acquisition of sufficient energy for maintenance and growth. by investigating the hormonal mechanisms of the somatotropic axis that link nutrition, fat metabolism, and lean tissue accretion, we can assess the physiological impact of decreased nutrient intake on growth. further, species that undergo seasonal periods of reduced intake as a part of their normal life history may have a differential seasonal response to nutrient restriction. t ...201020084663
environment and feeding change the ability of heart rate to predict metabolism in resting steller sea lions (eumetopias jubatus).the ability to use heart rate (fh) to predict oxygen consumption rates ([formula: see text]) in steller sea lions and other pinnipeds has been investigated in fasting animals. however, it is unknown whether established fh:[formula: see text] relationships hold under more complex physiological situations, such as when animals are feeding or digesting. we assessed whether fh could accurately predict [formula: see text] in trained steller sea lions while fasting and after being fed. using linear mi ...201120700598
dive behaviour impacts the ability of heart rate to predict oxygen consumption in steller sea lions (eumetopias jubatus) foraging at depth.the predictive relationship between heart rate (f(h)) and oxygen consumption (vo2) has been derived for several species of marine mammals swimming horizontally or diving in tanks to shallow depths. however, it is unclear how dive activity affects the f(h):vo2 relationship and whether the existing equations apply to animals diving to deeper depths. we investigated these questions by simultaneously measuring the f(h) and vo2 of steller sea lions (eumetopias jubatus) under different activity states ...201121653820
proportion of prey consumed can be determined from faecal dna using real-time pcr.reconstructing the diets of pinnipeds by visually identifying prey remains recovered in faecal samples is challenging because of differences in digestion and passage rates of hard parts. analysing the soft-matrix of faecal material using dna-based techniques is an alternative means to identify prey species consumed, but published techniques are largely nonquantitative, which limits their usefulness for some applications. we further developed and validated a real-time pcr technique using species- ...201121481211
aerial audiograms of several california sea lions (zalophus californianus) and steller sea lions (eumetopias jubatus) measured using single and multiple simultaneous auditory steady-state response methods.measurements of the electrophysiological auditory steady-state response (assr) have proven to be efficient for evaluating hearing sensitivity in odontocete cetaceans. in an effort to expand these methods to pinnipeds, assrs elicited by single and multiple simultaneous tones were used to measure aerial hearing thresholds in several california sea lions (zalophus californianus) and steller sea lions (eumetopias jubatus). there were no significant differences between thresholds measured using the s ...201121389199
spatial patterns and scaling behaviors of steller sea lion (eumetopias jubatus) distributions and their environment.fractal geometry and other multi-scale analyses have become popular tools for investigating spatial patterns of animal distributions in heterogeneous environments. in theory, changes in patterns of animal distributions with changes in scale reflect transitions between the controlling influences of one environmental factor or process over another. in an effort to find linkages between steller sea lions (eumetopias jubatus) and their environment, the objective of this study was to determine if the ...201121241711
accumulation and maternal transfer of polychlorinated biphenyls in steller sea lions (eumetopias jubatus) from prince william sound and the bering sea, alaska.the western stock of the steller sea lion (eumetopias jubatus) in the northern pacific ocean has declined by approximately 80% over the past 30 years. this led to the listing of this sea lion population as an endangered species in 1997. chemical pollution is [corrected] one of several contributing causes. in the present study, 145 individual pcbs were determined in tissues of male sea lions from tatitlek (prince william sound) and st. paul island (bering sea), and placentae from the aleutian isl ...201120965632
differentiating between steller sea lion (eumetopias jubatus) and northern fur seal (callorhinus ursinus) scats through analysis of faecal dna.we describe a method to determine the species of pinniped from faeces collected from sympatric steller sea lion (eumetopias jubatus) and northern fur seal (callorhinus ursinus) rookeries using newly developed species-specific primers that amplify a 667-669-base pair segment from the mitochondrial dna (mtdna) cytochrome b (cytb) gene region. the primers yielded the correct species in 100% of tissue samples from 10 known animals and 100% of faecal samples from 13 known animals. species could be id ...201121429117
addendum to “the cytotoxicity and genotoxicity of hexavalent chromium in steller sea lion lung fibroblasts compared to human lung fibroblasts” [comp biochem physiol c toxicol pharmacol. 152(1)91–8. 201121812147
discovery of an orthoreovirus in the aborted fetus of a steller sea lion (eumetopias jubatus).an aborted mid-gestational male steller sea lion fetus with an attached placenta was recovered on the floor of an open floating capture trap located off norris rock near denman island, british columbia. viral culture of the placenta demonstrated cytopathic effect. although no specific signal was obtained in microarray experiments using rna obtained from viral culture, elution and sequence analysis revealed the presence of a reovirus. complete genome pyrosequencing led to the identification of an ...201121795475
aerobic oral and rectal bacteria of free-ranging steller sea lion pups and juveniles (eumetopias jubatus) in alaska.bacteriologic cultures from oral, rectal, and lesion samples from free-ranging steller sea lion (ssl, eumetopias jubatus) pups and juveniles in alaska (2001-2005) were examined to determine frequency of infection by a specific subset of common and pathogenic aerobic bacteria. associations between isolated bacteria and age, sex, body condition, location, and sampling season were investigated. salmonella spp. isolates were further evaluated to determine spatial clustering (n=48) and to identify se ...201122102651
effects of hot-iron branding on heart rate, breathing rate and behaviour of anaesthetised steller sea lions.this study assessed the heart rate, breathing rate and behavioural responses of 12 juvenile steller sea lions during hot-iron branding under isoflurane anaesthesia. physiological and behavioural measures were recorded in four periods: baseline (five minutes), sham branding (one minute), branding (approximately 2.7 minutes) and postbranding (five minutes). no difference in heart rate was noted from baseline to sham branding, but heart rate increased from mean (sem) 78.3 (2.4) bpm in the baseline ...201121881020
the effects of two analgesic regimes on behavior after abdominal surgery in steller sea lions.this study examined the effects of two non-steroidal anti-inflammatory drug (nsaid) treatment protocols on the behavioral responses of juvenile steller sea lions after abdominal surgery. sea lions were randomly assigned to one of two treatments designed to control post-operative pain. the flunixin group (n=6) received flunixin meglumine (1mg/kg) administered as a single intramuscular (im) injection before extubation from surgery. the carprofen group (n=5) received carprofen (4.4 mg/kg) as an im ...201120932783
occurrence of pasteurellaceae bacteria in the oral cavity of selected marine mammal species.the occurrence of bacteria belonging to pasteurellaceae in the oral cavity of captive marine mammals was investigated using culture and subsequent geno- and phenotypic characterization and phylogenetic analyses. a total of 89 bacterial isolates from pinnipeds tentatively classified with the family pasteurellaceae were further characterized by phylogenetic analysis of rpob gene sequences, which showed that the isolates investigated formed five distinct groups. four strains from california sea lio ...201223272350
coxiella burnetii infection of marine mammals in the pacific northwest, 1997-2010.q fever is a zoonotic disease caused by the bacterium coxiella burnetii. humans are commonly exposed via inhalation of aerosolized bacteria derived from the waste products of domesticated sheep and goats, and particularly from products generated during parturition. however, many other species can be infected with c. burnetii, and the host range and full zoonotic potential of c. burnetii is unknown. two cases of c. burnetii infection in marine mammal placenta have been reported, but it is not kno ...201222247392
[helminthofauna of steller's sea lion (eumetopias jubatus) inhabiting the north-eastern coast of asia].helminths collected from 55 steller's sea lions in the western and central bering sea were examined. helminth species, their localization in the host organism, invasion indices, categories, and host ranges are reported. helminthofaunas of sea lions from various sea areas are compared. forming of the recent steller's sea lion helminthofauna and its links with other host are discussed. it was hypothesized that helminths do nor substantially affect the recent decline of the steller's sea lion abund ...201219370982
mortality related to spotted ratfish (hydrolagus colliei) in pacific harbor seals (phoca vitulina) in washington state.tissue perforation and penetration by dorsal fin spines of spotted ratfish (hydrolagus colliei) were responsible for the death of seven harbor seals (phoca vitulina) in washington state (usa) between 2006 and 2011. in six animals, necropsy revealed spines or spine parts that had perforated the esophagus or stomach and migrated into vital tissues, resulting in hemothorax, pneumothorax, pleuritis, and peritonitis. in a seventh case, a ratfish spine was recovered from the mouth of a harbor seal eut ...201223060509
mercury concentrations in hair from neonatal and juvenile steller sea lions (eumetopias jubatus): implications based on age and region in this northern pacific marine sentinel piscivore.mercury is a global contaminant of concern for the fetus and the neonate of piscivores. methylmercury, produced within marine ecosystems, is of particular concern as a readily absorbed neurotoxicant transported across the blood brain barrier and transplacentally. in the north pacific ocean, steller sea lions are broadly distributed apex predators and, as such, integrate complex food webs and the associated exposure and possible adverse effects of toxic and infectious agents. hair, including lanu ...201222815134
pbde flame retardants and pcbs in migrating steller sea lions (eumetopias jubatus) in the strait of georgia, british columbia, canada.polybrominated diphenyl ethers (pbdes) and polychlorinated biphenyls (pcbs) were measured in blubber biopsy samples from 22 live-captured steller sea lions (eumetopias jubatus) that had just entered the strait of georgia, british columbia, canada, for their overwintering feeding season. ∑pbde ranged from 50μgkg(-1) (lipid weight) in adult females to 3780μgkg(-1) in subadult individuals. ∑pcbs ranged from 272μgkg(-1) in adult females to 14280μgkg(-1) in subadult individuals. while most pbde and p ...201222560183
predation on an upper trophic marine predator, the steller sea lion: evaluating high juvenile mortality in a density dependent conceptual framework.the endangered western stock of the steller sea lion (eumetopias jubatus)--the largest of the eared seals--has declined by 80% from population levels encountered four decades ago. current overall trends from the gulf of alaska to the aleutian islands appear neutral with strong regional heterogeneities. a published inferential model has been used to hypothesize a continuous decline in natality and depressed juvenile survival during the height of the decline in the mid-late 1980's, followed by the ...201222272296
methods for estimating spatial trends in steller sea lion pup production using the kalman filter.many species exhibit spatially varying trends in population size and status, often driven by differences among factors affecting individual subpopulations. estimation and differentiation of such trends may be important for management, and a driving force for monitoring programs. the ability to estimate spatial differences in population trend may depend on assumptions regarding connectivity among subpopulations (stock structure or spatial overlap in stressors), information that is often poorly kn ...201324147416
inter-population movements of steller sea lions in alaska with implications for population separation.genetic studies and differing population trends support the separation of steller sea lions (eumetopias jubatus) into a western distinct population segment (wdps) and an eastern dps (edps) with the dividing line between populations at 144° w. despite little exchange for thousands of years, the gap between the breeding ranges narrowed during the past 15-30 years with the formation of new rookeries near the dps boundary. we analyzed >22,000 sightings of 4,172 sea lions branded as pups in each dps ...201323940543
maternal steller sea lion diets elevate fetal mercury concentrations in an area of population decline.total mercury concentrations ([thg]) measured in western aleutian island steller sea lion pup hair were the highest maximum [thg] documented in this endangered species to date. some pups exceeded concentrations at which other fish-eating mammals can exhibit adverse neurological and reproductive effects (21% and 15% pups above 20 and 30 μg/g in hair, respectively). of particular concern is fetal exposure to mercury during a particularly vulnerable stage of neurological development in late gestati ...201323545490
high diving metabolism results in a short aerobic dive limit for steller sea lions (eumetopias jubatus).the diving capacity of marine mammals is typically defined by the aerobic dive limit (adl) which, in lieu of direct measurements, can be calculated (cadl) from total body oxygen stores (tbo) and diving metabolic rate (dmr). to estimate cadl, we measured blood oxygen stores, and combined this with diving oxygen consumption rates (vo2) recorded from 4 trained steller sea lions diving in the open ocean to depths of 10 or 40 m. we also examined the effect of diving exercise on o2 stores by comparing ...201323354410
body condition and endocrine profiles of steller sea lion (eumetopias jubatus) pups during the early postnatal period.body condition indices have been useful in assessing the health of domestic and free ranging populations of terrestrial mammals. given the high energy demand and rapid growth during the postnatal period of steller sea lion (eumetopias jubatus) (ssl) pups, body condition was expected to be related to concentrations of a suite of hormones (cortisol, aldosterone, thyroxine, triiodothyronine, leptin) previously associated with changes in body mass and composition in developing pinnipeds. blood sampl ...201323313076
concentration profiles of pcb congeners in the blubber and liver of steller sea lions (eumetopias jubatus) from the coast of hokkaido, japan.the concentrations of pcb congeners in the blubber and liver of male and female steller sea lions (eumetopias jubatus; ssls) collected from the shakotan peninsula and the nemuro strait, hokkaido, japan in 2008 and 2010 were measured by hrgc-hrms, in order to express the concentration profiles in ssls at these regions. #153 predominated in both organs, followed by #138, #99 and #118. in males, #28 and #31 were concentrated particularly in the blubber, while #177 and #199 were accumulated specific ...201323306066
serum chemistry reference ranges for steller sea lion (eumetopias jubatus) pups from alaska: stock differentiation and comparisons within a north pacific sentinel species.blood chemistry and hematologic reference ranges are useful for population health assessment and establishing a baseline for future comparisons in the event of ecosystem changes due to natural or anthropogenic factors. the objectives of this study were to determine if there was any population spatial structure for blood variables of steller sea lion (eumetopias jubatus), an established sentinel species, and to report reference ranges for appropriate populations using standardized analyses. in ad ...201324419664
beneath the surface: profiling blubber depth in pinnipeds with infrared imaging.infrared thermography (irt) was assessed as a non-invasive tool to evaluate body condition in juvenile female harbor seals (phoca vitulina), (n=6) and adult female steller sea lions (eumetopias jubatus), (n=2). surface temperature determined by irt and blubber depth assessed with portable imaging ultrasound were monitored concurrently at eight body sites over the course of a year in long-term captive individuals under controlled conditions. site-specific differences in surface temperature were n ...201324229798
molecular systematics of pinniped hookworms (nematoda: uncinaria): species delimitation, host associations and host-induced morphometric variation.hookworms of the genus uncinaria have been widely reported from juvenile pinnipeds, however investigations of their systematics has been limited, with only two species described, uncinaria lucasi from northern fur seals (callorhinus ursinus) and uncinaria hamiltoni from south american sea lions (otaria flavescens). hookworms were sampled from these hosts and seven additional species including steller sea lions (eumetopias jubatus), california sea lions (zalophus californianus), south american fu ...201324162075
linking reproduction and survival can improve model estimates of vital rates derived from limited time-series counts of pinnipeds and other species.we propose a method to model the physiological link between somatic survival and reproductive output that reduces the number of parameters that need to be estimated by models designed to determine combinations of birth and death rates that produce historic counts of animal populations. we applied our reproduction and somatic survival linked (rssl) method to the population counts of three species of north pacific pinnipeds (harbor seals, phoca vitulina richardii (gray, 1864); northern fur seals, ...201324324541
coxiella burnetii in northern fur seals and steller sea lions of alaska.coxiella burnetii, a zoonotic bacterium, has recently been identified in several marine mammal species on the pacific coast of north america, but little is known about the epidemiology, transmission, and pathogenesis in these species. we tested sera archived from northern fur seals (nfs, callorhinus ursinus; n=236) and steller sea lions (ssl, eumetopias jubatus; n=72) sampled in alaska for c. burnetii antibodies, and vaginal swabs from nfs (n=40) for c. burnetii by qpcr. the antibody prevalence ...201323568925
complete genome analysis identifies tvärminne avian virus as a candidate new species within the genus orthoreovirus.orthoreoviruses have been associated with a variety of diseases in domesticated poultry and wild-living birds. in 2002, a reovirus strain named tvärminne avian virus (tvav), was identified in finland in a crow showing neurological disorders. the objective of this study was the molecular characterization of this novel reovirus strain. genome sequencing was performed by combining semiconductor sequencing and traditional capillary sequencing. sequence and phylogenetic analyses showed that tvav shar ...201424421111
halogenated phenolic contaminants in the blood of marine mammals from japanese coastal waters.information on accumulation of halogenated phenolic contaminants in the blood of marine mammal is limited. the present study, we determined the residue levels and patterns of chlorinated and brominated phenolic contaminants (oh-pcbs, oh-pbdes and bromophenols) in the blood collected from pinnipeds (northern fur seal, spotted seal, steller sea lion and ribbon seal) and small cetaceans (harbor porpoise and dall's porpoise) from japanese coastal waters. concentrations of pcbs and oh-pcbs found in p ...201424060385
inflation and deflation pressure-volume loops in anesthetized pinnipeds confirms compliant chest and lungs.we examined structural properties of the marine mammal respiratory system, and tested scholander's hypothesis that the chest is highly compliant by measuring the mechanical properties of the respiratory system in five species of pinniped under anesthesia (pacific harbor seal, phoca vitulina; northern elephant seal, mirounga angustirostris; northern fur seal callorhinus ursinus; california sea lion, zalophus californianus; and steller sea lion, eumetopias jubatus). we found that the chest wall co ...201425426080
occurrence and genotypic analysis of trichinella species in alaska marine-associated mammals of the bering and chukchi seas.the zoonotic parasite trichinella is the causative agent of trichinellosis outbreaks in the circumpolar arctic. subsistence communities are particularly prone to trichinellosis due to traditional meat preparation methods and regional presence of a freeze-tolerant trichinella species (trichinella nativa). this study is the first application of a validated artificial digestion method in determining incidence of trichinella sp. in alaskan mammals. infection incidence in pinniped species (erignathus ...201424373515
sarcocystis canis associated hepatitis in a steller sea lion (eumetopias jubatus) from alaska.sarcocystis canis infection was associated with hepatitis in a steller sea lion (eumetopias jubatus). intrahepatocellular protozoal schizonts were among areas of necrosis and inflammation. the parasite was genetically identical to s. canis and is the first report in a steller sea lion, indicating another intermediate host species for s. canis.201424484486
steller sea lions (eumetopias jubatus) have greater blood volumes, higher diving metabolic rates and a longer aerobic dive limit when nutritionally stressed.marine mammal foraging behaviour inherently depends on diving ability. declining populations of steller sea lions may be facing nutritional stress that could affect their diving ability through changes in body composition or metabolism. our objective was to determine whether nutritional stress (restricted food intake resulting in a 10% decrease in body mass) altered the calculated aerobic dive limit (cadl) of four captive sea lions diving in the open ocean, and how this related to changes in obs ...201424198263
no evidence of metabolic depression in western alaskan juvenile steller sea lions (eumetopias jubatus).steller sea lion (eumetopias jubatus) populations have undergone precipitous declines through their western alaskan range over the last four decades with the leading hypothesis to explain this decline centering around changing prey quality, quantity, or availability for this species (i.e., nutritional stress hypothesis). under chronic conditions of reduced food intake sea lions would conserve energy by limiting energy expenditures through lowering of metabolic rate known as metabolic depression. ...201424416394
maternal-to-fetal transfer and concentration profiles of pcb congeners for steller sea lions (eumetopias jubatus) from hokkaido, japan.the concentrations of pcb congeners in the blubber and liver of mother steller sea lions (eumetopias jubatus; ssls) and their fetuses from the coast of hokkaido, japan in 2008, 2010 and 2012 were analyzed by hrgc-hrms, in order to elucidate pcb congener profiles and maternal-to-fetal transfer of pcbs in ssls. σpcbs in the fetuses were 1400 ± 660 (the mean ± sd) ng/g-fat in the blubber and 570 ± 320 ng/g-fat in the liver, respectively. there was a concern that ssls had been contaminated by pcbs d ...201424269191
a longitudinal study of steller sea lion natality rates in the gulf of alaska with comparisons to census data.steller sea lion (eumetopias jubatus) numbers in the western distinct population segment are beginning to recover following the dramatic decline that began in the 1970s and ended around the turn of the century. low female reproductive rates (natality) may have contributed to the decline and remain an issue of concern for this population. during the 2000s we found high natality among steller sea lions in the gulf of alaska indicating a healthy population. this study extends these previous estimat ...201425383865
crossing to safety: dispersal, colonization and mate choice in evolutionarily distinct populations of steller sea lions, eumetopias jubatus.population growth typically involves range expansion and establishment of new breeding sites, while the opposite occurs during declines. although density dependence is widely invoked in theoretical studies of emigration and colonization in expanding populations, few empirical studies have documented the mechanisms. still fewer have documented the direction and mechanisms of individual transfer in declining populations. here, we screen large numbers of pups sampled on their natal rookeries for va ...201425266462
the effect of organohalogen contaminants on western steller sea lion survival and movement in the russian far east.the western stock of steller sea lions (eumetopias jubatus) have experienced dramatic declines since the 1960s, particularly in the western alaskan and asian portions, which have continued to decline or stabilized at low levels. multiple causes for this decline have been proposed and may include anthropogenic contamination from organohalogen contaminants (ocs). these include polychlorinated biphenyls (pcbs) and dichlorodiphenyltrichloroethane (ddt), which have not been ruled out as a potential c ...201424887189
the effects of birth weight and maternal care on survival of juvenile steller sea lions (eumetopias jubatus).steller sea lions were listed as endangered following a collapse of the western distinct population beginning in the late 1970s. low juvenile survival has been implicated as a factor in the decline. i conducted a multistate mark-recapture analysis to estimate juvenile survival in an area of the western population where sea lions are showing signs of recovery. survival for males and females was 80% between 3 weeks and 1 year of age. approximately 20% of juveniles continued to be nursed by their m ...201424804679
drag, but not buoyancy, affects swim speed in captive steller sea lions.swimming at an optimal speed is critical for breath-hold divers seeking to maximize the time they can spend foraging underwater. theoretical studies have predicted that the optimal swim speed for an animal while transiting to and from depth is independent of buoyancy, but is dependent on drag and metabolic rate. however, this prediction has never been experimentally tested. our study assessed the effects of buoyancy and drag on the swim speed of three captive steller sea lions (eumetopias jubatu ...201424771620
assessment of mercury and selenium tissular concentrations and total mercury body burden in 6 steller sea lion pups from the aleutian islands.concentrations of total mercury ([thg]) and selenium ([tse]) were measured in several tissue compartments in steller sea lion (eumetopias jubatus) pups; in addition we determined specific compartment and body burdens of thg. compartmental and body burdens were calculated by multiplying specific compartment fresh weight by the [thg] (summing compartment burdens equals body burden). in all 6 pup tissue sets (1) highest [thg] was in hair, (2) lowest [thg] was in bone, and (3) pelt, muscle and liver ...201424661459
sensitivity to hypercapnia and elimination of co2 following diving in steller sea lions (eumetopias jubatus).the diving ability of marine mammals is a function of how they use and store oxygen and the physiological control of ventilation, which is in turn dependent on the accumulation of co2. to assess the influence of co2 on physiological control of dive behaviour, we tested how increasing levels of inspired co2 (hypercarbia) and decreasing inspired o2 (hypoxia) affected the diving metabolic rate, submergence times, and dive recovery times (time to replenish o2 stores and eliminate co2) of freely divi ...201424604293
feeding kinematics and performance of basal otariid pinnipeds, steller sea lions and northern fur seals: implications for the evolution of mammalian feeding.feeding performance studies can address questions relevant to feeding ecology and evolution. our current understanding of feeding mechanisms for aquatic mammals is poor. therefore, we characterized the feeding kinematics and performance of five steller sea lions (eumetopias jubatus) and six northern fur seals (callorhinus ursinus). we tested the hypotheses that both species use suction as their primary feeding mode, and that rapid jaw opening was related to suction generation. steller sea lions ...201526449976
tooth size variation in pinniped dentitions.it is contentious whether size variation among mammalian teeth is heterogeneous or homogeneous, whether the coefficient of variation is reliable, and whether the standard deviation of log-transformed data and the residual of standard deviation on mean variable size are useful replacements for the coefficient of variation. most studies of tooth size variation have been on mammals with complex-crowned teeth, with relatively little attention paid to taxa with simple-crowned teeth, such as pinnipedi ...201526317362
uridine diphosphate-glucuronosyltransferase (ugt) xenobiotic metabolizing activity and genetic evolution in pinniped species.there are various interspecies differences in xenobiotic-metabolizing enzymes. it is known that cats show slow glucuronidation of drugs such as acetaminophen and strong side effects due to the ugt1a6 pseudogene. recently, the ugt1a6 pseudogene was found in the northern elephant seal and otariidae was suggested to be ugt1a6-deficient. from the results of measurements of uridine diphosphate-glucuronosyltransferase (ugt) activity using liver microsomes, the steller sea lion, northern fur seal, and ...201526179383
the effect of novel research activities on long-term survival of temporarily captive steller sea lions (eumetopias jubatus).two novel research approaches were developed to facilitate controlled access to, and long-term monitoring of, juvenile steller sea lions for periods longer than typically afforded by traditional fieldwork. the transient juvenile steller sea lion project at the alaska sealife center facilitated nutritional, physiological, and behavioral studies on the platform of temporary captivity. temporarily captive sea lions (tjs, n = 35) were studied, and were intraperitoneally implanted with life history t ...201526580549
population trend and elasticities of vital rates for steller sea lions (eumetopias jubatus) in the eastern gulf of alaska: a new life-history table analysis.steller sea lion (eumetopias jubatus) numbers are beginning to recover across most of the western distinct population segment following catastrophic declines that began in the 1970s and ended around the turn of the century. this study makes use of contemporary vital rate estimates from a trend-site rookery in the eastern gulf of alaska (a sub-region of the western population) in a matrix population model to estimate the trend and strength of the recovery across this region between 2003 and 2013. ...201526488901
validating the relationship between 3-dimensional body acceleration and oxygen consumption in trained steller sea lions.we tested the ability of overall dynamic body acceleration (odba) to predict the rate of oxygen consumption ([formula: see text]) in freely diving steller sea lions (eumetopias jubatus) while resting at the surface and diving. the trained sea lions executed three dive types-single dives, bouts of multiple long dives with 4-6 dives per bout, or bouts of multiple short dives with 10-12 dives per bout-to depths of 40 m, resulting in a range of activity and oxygen consumption levels. average metabol ...201526002519
assessment of competition between fisheries and steller sea lions in alaska based on estimated prey biomass, fisheries removals and predator foraging behaviour.a leading hypothesis to explain the dramatic decline of steller sea lions (eumetopias jubatus) in western alaska during the latter part of the 20th century is a change in prey availability due to commercial fisheries. we tested this hypothesis by exploring the relationships between sea lion population trends, fishery catches, and the prey biomass accessible to sea lions around 33 rookeries between 2000 and 2008. we focused on three commercially important species that have dominated the sea lion ...201525950178
a nutrigenomic approach to detect nutritional stress from gene expression in blood samples drawn from steller sea lions.gene expression profiles are increasingly being used as biomarkers to detect the physiological responses of a number of species to disease, nutrition, and other stressors. however, little attention has been given to using gene expression to assess the stressors and physiological status of marine mammals. we sought to develop and validate a nutrigenomic approach to quantify nutritional stress in steller sea lions (eumetopias jubatus). we subjected 4 female steller sea lions to 3 feeding regimes o ...201525700740
dive behaviour can predict metabolic expenditure in steller sea lions.quantification of costs associated with foraging contributes to understanding the energetic impact that changes in prey availability have on the energy balance of an animal and the fitness of populations. however, estimating the costs of foraging is difficult for breath-hold divers, such as steller sea lions, that feed underwater. we developed models parameterized with data from free-diving captive steller sea lions to estimate the costs incurred by wild animals while foraging. we measured divin ...201527293736
physiological predictors of long-term survival in juvenile steller sea lions (eumetopias jubatus).this study builds on a continued effort to document potential long-term research impacts on the individual, as well as to identify potential markers of survival for use in a field framework. the transient juvenile steller sea lion (tj) project was developed as a novel framework to gain access to wild individuals. we used three analyses to evaluate and predict long-term survival in temporarily captive sea lions (n = 45) through cormack-jolly-seber open population modelling techniques. the first a ...201527293728
the influence of time in captivity, food intake and acute trauma on blood analytes of juvenile steller sea lions, eumetopias jubatus.the steller sea lion, eumetopias jubatus, has experienced regionally divergent population trends over recent decades. one potential mechanism for this disparity is that local factors cause reduced health and, therefore, reduced survival of individuals. the use of blood parameters to assess sea lion health may help to identify whether malnutrition, disease and stress are important drivers of current trends, but such assessments require species-specific knowledge of how parameters respond to vario ...201527293693
isolation and genomic characterization of a novel orthoreovirus from a brown-eared bulbul (hypsipetes amaurotis) in japan.five species, mammalian orthoreovirus, avian orthoreovirus (arv), nelson bay orthoreovirus (nbv), baboon orthoreovirus and reptilian orthoreovirus, have been identified in the genus orthoreovirus. their genomes each consist of 10 dsrna segments. a novel orthoreovirus was isolated from the haemorrhagic intestine of a dead brown-eared bulbul (hypsipetes amaurotis) in japan. the virus formed syncytia in caco-2 and vero cells. electron microscopy revealed non-enveloped capsids of ~70 nm diameter, wh ...201525740958
correction: assessment of competition between fisheries and steller sea lions in alaska based on estimated prey biomass, fisheries removals and predator foraging behaviour. 201526244864
age specific survival rates of steller sea lions at rookeries with divergent population trends in the russian far east.after a dramatic population decline, steller sea lions have begun to recover throughout most of their range. however, steller sea lions in the western aleutians and commander islands are continuing to decline. comparing survival rates between regions with different population trends may provide insights into the factors driving the dynamics, but published data on vital rates have been extremely scarce, especially in regions where the populations are still declining. fortunately, an unprecedented ...201526016772
respiratory function in voluntary participating patagonia sea lions (otaria flavescens) in sternal recumbency.we measured esophageal pressures (n = 4), respiratory flow rates (n = 5), and expired o2 and co2 (n = 4) in five adult patagonia sea lions (otaria flavescens, body mass range 94.3-286.0 kg) during voluntary breaths while laying down out of water. the data were used to estimate the dynamic specific lung compliance (scl), the o2 consumption rate ([formula: see text]o2) and co2 production rates ([formula: see text]co2) during rest. our results indicate that the resting tidal volume in patagonia sea ...201627899896
the ancestral carnivore karyotype as substantiated by comparative chromosome painting of three pinnipeds, the walrus, the steller sea lion and the baikal seal (pinnipedia, carnivora).karyotype evolution in carnivora is thoroughly studied by classical and molecular cytogenetics and supplemented by reconstructions of ancestral carnivora karyotype (ack). however chromosome painting information from two pinniped families (odobenidae and otariidae) is noticeably missing. we report on the construction of the comparative chromosome map for species from each of the three pinniped families: the walrus (odobenus rosmarus, odobenidae-monotypic family), near threatened steller sea lion ...201626821159
evaluating hair as a predictor of blood mercury: the influence of ontogenetic phase and life history in pinnipeds.mercury (hg) biomonitoring of pinnipeds increasingly utilizes nonlethally collected tissues such as hair and blood. the relationship between total hg concentrations ([thg]) in these tissues is not well understood for marine mammals, but it can be important for interpretation of tissue concentrations with respect to ecotoxicology and biomonitoring. we examined [thg] in blood and hair in multiple age classes of four pinniped species. for each species, we used paired blood and hair samples to quant ...201626149950
organochlorine contaminant concentrations in multiple tissues of free-ranging steller sea lions (eumetopias jubatus) in alaska.the relationships of selected organochlorine (oc) contaminants between blubber, blood, feces, and milk of young, free-ranging steller sea lions (eumetopias jubatus) were examined. both between and within each tissue there was considerable individual variation. in spite of the variation, similar patterns were observed across the tissues for most of the selected pcb congeners. in all four tissues, the major pcb congeners were pcb101, pcb118, pcb138, and pcb153. the most prominent congener, both as ...201626524270
prevalence of algal toxins in alaskan marine mammals foraging in a changing arctic and subarctic environment.current climate trends resulting in rapid declines in sea ice and increasing water temperatures are likely to expand the northern geographic range and duration of favorable conditions for harmful algal blooms (habs), making algal toxins a growing concern in alaskan marine food webs. two of the most common hab toxins along the west coast of north america are the neurotoxins domoic acid (da) and saxitoxin (stx). over the last 20 years, da toxicosis has caused significant illness and mortality in m ...201628073526
supporting risk assessment: accounting for indirect risk to ecosystem components.the multi-scalar complexity of social-ecological systems makes it challenging to quantify impacts from human activities on ecosystems, inspiring risk-based approaches to assessments of potential effects of human activities on valued ecosystem components. risk assessments do not commonly include the risk from indirect effects as mediated via habitat and prey. in this case study from british columbia, canada, we illustrate how such "indirect risks" can be incorporated into risk assessments for sev ...201627632287
averaged propulsive body acceleration (apba) can be calculated from biologging tags that incorporate gyroscopes and accelerometers to estimate swimming speed, hydrodynamic drag and energy expenditure for steller sea lions.forces due to propulsion should approximate forces due to hydrodynamic drag for animals horizontally swimming at a constant speed with negligible buoyancy forces. propulsive forces should also correlate with energy expenditures associated with locomotion-an important cost of foraging. as such, biologging tags containing accelerometers are being used to generate proxies for animal energy expenditures despite being unable to distinguish rotational movements from linear movements. however, recent m ...201627285467
dive, food, and exercise effects on blood microparticles in steller sea lions (eumetopias jubatus): exploring a biomarker for decompression sickness.recent studies of stranded marine mammals indicate that exposure to underwater military sonar may induce pathophysiological responses consistent with decompression sickness (dcs). however, dcs has been difficult to diagnose in marine mammals. we investigated whether blood microparticles (mps, measured as number/μl plasma), which increase in response to decompression stress in terrestrial mammals, are a suitable biomarker for dcs in marine mammals. we obtained blood samples from trained steller s ...201626843583
first isolation of streptococcus halichoeri and streptococcus phocae from a steller sea lion (eumetopias jubatus) in south korea.streptococcus species are emerging potential pathogens in marine mammals. we report the isolation and identification of streptococcus halichoeri and streptococcus phocae in a steller sea lion (eumetopias jubatus) in south korea.201626555114
a high-resolution area in the retinal ganglion cell layer of the steller's sea lion (eumetopias jubatus): a topographic study. 201615354821
contamination status and accumulation characteristics of heavy metals and arsenic in five seabird species from the central bering sea.seabirds are marine top predators and accumulate high levels of metals and metalloids in their tissues. contamination by metals in the highly productive offshore region has become a matter of public concern. it is home to 80% of the seabird population in the usa, 95% of northern fur seals (callorhinus ursinus), and major populations of steller sea lions (eumetopias jubatus), walruses (odobenus rosmarus) and whales. here, the concentrations of eight heavy metals (hg, cd, cr, co, ni, cu, zn and pb ...201728302954
characterization of species differences in xenobiotic metabolism in non-experimental animals.the ability to metabolize xenobiotics in organisms has a wide degree of variation among organisms. this is caused by differences in the pattern of xenobiotic bioaccumulation among organisms, which affects their tolerance. it has been reported in the veterinary field that glucuronidation (ugt) activity in cats, acetylation activity in dogs and sulfation (sult) activity in pigs are sub-vital in these species, respectively, and require close attention when prescribing the medicine. on the other han ...201728250318
physiological constraints and energetic costs of diving behaviour in marine mammals: a review of studies using trained steller sea lions diving in the open ocean.marine mammals are characterized as having physiological specializations that maximize the use of oxygen stores to prolong time spent under water. however, it has been difficult to undertake the requisite controlled studies to determine the physiological limitations and trade-offs that marine mammals face while diving in the wild under varying environmental and nutritional conditions. for the past decade, steller sea lions (eumetopias jubatus) trained to swim and dive in the open ocean away from ...201727686668
serologic evidence of brucella infection in pinnipeds along the coast of hokkaido, the northernmost main island of japan.brucella infection in hokkaido was serologically surveyed in four species of pinnipeds inhabiting cape erimo during 2008-2013 and the shiretoko peninsula in 1999, by enzyme-linked immunosorbent assay using brucella abortus and b. canis as antigens. anti-brucella positive sera showed higher absorbance to b. abortus than b. canis in almost all samples. anti-b. abortus antibodies were detected in serum samples from 24% (n=55) of western pacific harbor seals (phoca vitulina stejnegeri) in cape erimo ...201728262966
serum estradiol and progesterone profiles during estrus, pseudopregnancy, and active gestation in steller sea lions.while the proximate driver behind the decline of the western stock of steller sea lions (eumetopias jubatus, >80% since 1970s) is likely multifactorial, the population reduction may have been powered by a decrease in fecundity. a harvest of steller sea lions in the 1970s and 80s revealed a 30% reduction in the proportion of pregnant females from early (october-november) to late gestation (april-may). identification and quantification of these reproductive failures are difficult when we lack spec ...201728901587
natal and breeding philopatry of female steller sea lions in southeastern alaska.information on drivers of dispersal is critical for wildlife conservation but is rare for long-lived marine mammal species with large geographic ranges. we fit multi-state mark-recapture models to resighting data of 369 known-aged steller sea lion (eumetopias jubatus) females marked as pups on their natal rookeries in southeastern alaska from 1994-2005 and monitored from 2001-15. we estimated probabilities of females being first observed parous at their natal site (natal philopatry), and of not ...201728591130
udp-glucuronosyltransferase (ugt) 2b subfamily interspecies differences in carnivores.udp-glucuronosyltransferases (ugts) are among the most important xenobiotic metabolizing enzymes that conjugate a wide range of chemicals. previous studies showed that felidae and pinnipedia species have very low ugt activities toward some phenolic compounds because of the ugt1a6 pseudogene and small numbers of ugt1a isozymes. in addition to the ugt1as, ugt2bs isozymes also conjugate various endogenous (e.g., estrogens, androgens, and bile acids) and exogenous compounds (opioids, nsaids, and env ...201728453659
oil spills and marine mammals in british columbia, canada: development and application of a risk-based conceptual framework.marine mammals are inherently vulnerable to oil spills. we developed a conceptual framework to evaluate the impacts of potential oil exposure on marine mammals and applied it to 21 species inhabiting coastal british columbia (bc), canada. oil spill vulnerability was determined by examining both the likelihood of species-specific (individual) oil exposure and the consequent likelihood of population-level effects. oil exposure pathways, ecology, and physiological characteristics were first used to ...201728695252
estimating dispersal rates of steller sea lion (eumetopias jubatus) mother-pup pairs from a natal rookery using mark-resight data.to monitor population trends of steller sea lions (eumetopias jubatus) in alaska, newborn pups are counted during aerial surveys. these surveys are scheduled to occur after the majority of pups are born, but before pups begin to spend significant time in the water. some studies have reported dispersal of mother-pup pairs away from breeding beaches during the pupping season (july), which may influence survey results. using a multistate mark-recapture model with state uncertainty, we estimated the ...201729211808
extralobar pulmonary sequestration in two pinniped species.two cases of extralobar pulmonary sequestrations from a walrus (odobenus rosmarus) and a steller sea lion (eumetopias jubatus) are described in the present study. grossly, an independent, soft unilocular cystic mass was found within the abdominal cavities of both animals, adherent to the diaphragm in o. rosmarus and attached to the cardia of the stomach in e. jubatus. histopathologically, the cysts were lined by pseudostratified ciliated columnar epithelium with abundant goblet cells, while the ...201728924092
characterizing estrus by trans-abdominal ultrasounds, fecal estrone-3-glucuronide, and vaginal cytology in the steller sea lion (eumetopias jubatus).the ability to monitor the estrus cycle in wild and captive marine species is important for identifying reproductive failures, ensuring a successful breeding program, and monitoring animal welfare. minimally invasive sampling methods to monitor estrus in captive populations have been developed, but results suggest these tools can be species-specific in their precision and accuracy. therefore, the minimally invasive sampling methods of trans-abdominal ultrasounds, a fecal steroid analysis (estron ...201830081245
hair mercury concentrations in the spotted seal (phoca largha) pups from the sea of japan.this publication presents the results of a study of the total mercury (thg) concentration in the fetal hair (lanugo) of the young spotted seals inhabiting the peter the great bay, sea of japan. we analyzed samples from pups that were collected in 2014-2017 at the seal breeding grounds. the concentration of total mercury was determined by atomic absorption spectrometry. the concentration of thg ranged from 1.52 to 6.68 μg/g dry weight. mercury concentration in the lanugo exceeds that found in the ...201830022391
temporal records of diet diversity dynamics in individual adult female steller sea lion (eumetopias jubatus) vibrissae.detailed information on the nutrition of free-ranging mammals contributes to the understanding of life history requirements, yet is often quite limited temporally for most species. reliable dietary inferences can be made by analyzing the stable carbon (c) and nitrogen (n) isotopic values (δ13c and δ15n) of some consumer tissues; exactly which tissue is utilized dictates the inferential scope. steller sea lion (ssl) vibrissae are grown continuously without shedding and thus provide a continuous m ...201829948317
juvenile steller sea lion (eumetopias jubatus) utilization distributions in the gulf of alaska.a utilization distribution quantifies the temporal and spatial probability of space use for individuals or populations. these patterns in movement arise from individuals' internal state and from their response to the external environment, and thus can provide insights for assessing factors associated with the management of threatened populations. the western distinct population segment of the steller sea lion (eumetopias jubatus) has declined to approximately 20% of levels encountered 40 years a ...201829785269
correction: natal and breeding philopatry of female steller sea lions in southeastern alaska.[this corrects the article doi: 10.1371/journal.pone.0176840.].201829677218
reference ranges and age-related and diving exercise effects on hematology and serum chemistry of female steller sea lions ( eumetopias jubatus).decreased health may have lowered the birth and survival rates of steller sea lions ( eumetopias jubatus) in the gulf of alaska and aleutian islands over the past 30 yr. reference ranges for clinical hematology and serum chemistry parameters needed to assess the health of wild sea lion populations are limited. here, blood parameters were serially measured in 12 captive female steller sea lions ranging in age from 3 wk to 16 yr to establish baseline values and investigate age-related changes. whe ...201829517439
brucella antibodies in alaskan true seals and eared seals-two different stories.brucella pinnipedialis was first isolated from true seals in 1994 and from eared seals in 2008. although few pathological findings have been associated with infection in true seals, reproductive pathology including abortions, and the isolation of the zoonotic strain type 27 have been documented in eared seals. in this study, a brucella enzyme-linked immunosorbent assay (elisa) and the rose bengal test (rbt) were initially compared for 206 serum samples and a discrepancy between the tests was fou ...201829445729
survival of adult steller sea lions in alaska: senescence, annual variation and covariation with male reproductive success.population dynamics of long-lived vertebrates depend critically on adult survival, yet factors affecting survival and covariation between survival and other vital rates in adults remain poorly examined for many taxonomic groups of long-lived mammals (e.g. actuarial senescence has been examined for only 9 of 34 extant pinniped species using longitudinal data). we used mark-recapture models and data from 2795 steller sea lion (eumetopias jubatus) pups individually marked at four of five rookeries ...201829410794
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