| carnivora: the primary structure of the pacific walrus (odobenus rosmarus divergens, pinnipedia) hemoglobin. | the primary structure of the alpha- and beta-chains of the hemoglobin from the pacific walrus (odobenus rosmarus divergens, pinnipedia) is presented. sequence analysis revealed only one hemoglobin component whereas two bands were found in polyacrylamide gel electrophoresis. the globin chains were separated by high-performance liquid chromatography and the sequences determined by automatic liquid- and gas-phase sequencing of the chains and their tryptic peptides. the alpha-chains show 20 and the ... | 1989 | 2706084 |
| antibodies to marine caliciviruses in the pacific walrus (odobenus rosmarus divergens illiger). | sera from 155 pacific walruses (odobenus rosmarus divergens illiger), sampled in the chukchi sea during the summer of 1983, were tested for serum neutralizing (sn) antibodies to six marine calicivirus serotypes. serotypes tested included san miguel sea lion virus (smsv) types 1, 5, 8, and 10, previously isolated from northern fur seals (callorhinus ursinus linné) in the bering sea; walrus calicivirus (wcv), previously isolated from walrus feces collected off sea ice in the chukchi sea; and tilla ... | 1986 | 3712641 |
| prevalence and distribution of serum neutralizing antibodies to tillamook (bovine) calicivirus in selected populations of marine mammals. | neutralizing antibodies to tillamook calicivirus (tcv) were found in sera collected from california sea lions (zalophus c. californianus lesson) in 1983 and 1984 and in sera collected from steller sea lions (eumetopias jubatus schreber) in 1976 and 1985. the combined prevalence of antibodies for these two species was 10/228 = 4.38%. titers ranged from 1:20 (five animals), to 1:40 (four animals), to 1:80 (one animal) by standard microtiter neutralization assay. the seropositive pinnipeds were dis ... | 1987 | 3820428 |
| population structure and gene flow of the atlantic walrus (odobenus rosmarus rosmarus) in the eastern atlantic arctic based on mitochondrial dna and microsatellite variation. | the population structure of the atlantic walrus, odobenus rosmarus rosmarus, was studied using 11 polymorphic microsatellites and restriction fragment length polymorphism detected in the nadh-dehydrogenase nd1, nd2 and nd3/4 segments in mtdna. a total of 105 walrus samples were analysed from northwest (nw) greenland, east (e) greenland, svalbard and franz joseph land. two of the 10 haplotypes detected in the four samples were diagnostic for the nw greenland sample, which implied that the group o ... | 1998 | 9787444 |
| twenty years of trace metal analyses of marine mammals in alaska: evaluation and summation. | the compilation of existing data on contaminants in the marine food chain is essential in addressing concerns regarding the magnitude of potential human exposures and in the evaluation of subsistence food safety. this paper presents a summary of studies on trace metals in tissues of alaska marine mammals from the 1970s to the present, along with derived mean tissue trace metal concentrations. the derived mean can serve as a norm against which future monitoring results may be compared, and may be ... | 1998 | 10093345 |
| viral and bacterial serology of free-ranging pacific walrus. | serum or heparinized plasma samples were obtained between 1994 and 1996 from 20 male and 20 female adult free-ranging pacific walrus (odobenus rosmarus divergens) from st. lawrence island and round island, alaska. samples were screened for antibodies to some potentially pathogenic bacteria and viruses. no sample had detectable antibody to brucella spp. three of 40 (8%) had low antibody titers to leptospira interrogans serovars. phocine distemper virus antibodies were not detected. serologic resp ... | 2002 | 11838234 |
| novel sound production through contingency learning in the pacific walrus (odobenus rosmarus divergens). | walruses (odobenus rosmarus) are highly vocal amphibious mammals with a range of anatomical specializations that can provide plasticity to their sound emissions. the objective of this descriptive study was to determine whether contingency learning could be used to increase variability and induce novelty in the acoustic behavior of walruses. the subjects were two twelve-year-old captive walruses, a male and a female that had previously been conditioned using food reinforcement to produce several ... | 2008 | 18038276 |
| 137cs and 210po in pacific walrus and bearded seal from st. lawrence island, alaska. | the activity concentration of cesium-137 ((137)cs) and naturally-occurring polonium-210 ((210)po) were measured in the muscle tissue, kidney and liver of pacific walrus (odobenus rosmarus divergens) and bearded seal (erignathus barbatus) collected by native hunters from the bering sea during may 1996. the mean (137)cs concentrations in muscle, liver and kidney of pacific walrus were 0.07, 0.09 and 0.07 bq kg(-1) (n=5, wet weight), respectively, and 0.17, 0.10, and 0.17 bq kg(-1) (n=2, wet weight ... | 2008 | 18371988 |
| Use of Human Chorionic Gondadotropoin in a Male Pacific Walrus (Odobenus rosmarus divergens) to Induce Rut and Achieve a Pregnancy in a Nulliparous Female. | Walrus in United States zoos have a very low reproductive rate of 11 births in 80 years, and little is known about Pacific walrus (Odobenus rosmarus divergens) reproductive biology. To address this, we initiated a program in which detailed biological data were recorded on captive walrus. As part of a seven year study, one male and one female 16-year-old captive Pacific walrus were carefully monitored with weekly serum hormone analysis, daily glans penis smears for spermatozoa, and abdominal ult ... | 2011 | 22207706 |
| 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 ... | 2014 | 24373515 |
| antidog igg secondary antibody successfully detects igg in a variety of aquatic mammals. | serological tests play an important role in the detection of wildlife diseases. however, while there are many commercial assays and reagents available for domestic species, there is a need to develop efficient serological assays for wildlife. in recent years, marine mammals have represented a wildlife group with emerging infectious diseases, such as influenza, brucellosis, and leptospirosis. however, with the exception of disease-agent-specific assays or functional assays, few reports describe t ... | 2016 | 28080908 |
| a colostrum trypsin inhibitor gene expressed in the cape fur seal mammary gland during lactation. | the colostrum trypsin inhibitor (cti) gene and transcript were cloned from the cape fur seal mammary gland and cti identified by in silico analysis of the pacific walrus and polar bear genomes (order carnivora), and in marine and terrestrial mammals of the orders cetartiodactyla (yak, whales, camel) and perissodactyla (white rhinoceros). unexpectedly, weddell seal cti was predicted to be a pseudogene. cape fur seal cti was expressed in the mammary gland of a pregnant multiparous seal, but not in ... | 2016 | 26639991 |
| first molecular detection and characterization of herpesvirus and poxvirus in a pacific walrus (odobenus rosmarus divergens). | herpesvirus and poxvirus can infect a wide range of species: herpesvirus genetic material has been detected and amplified in five species of the superfamily pinnipedia; poxvirus genetic material, in eight species of pinnipedia. to date, however, genetic material of these viruses has not been detected in walrus (odobenus rosmarus), another marine mammal of the pinnipedia clade, even though anti-herpesvirus antibodies have been detected in these animals. | 2014 | 25527906 |
| 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 ... | 2015 | 26179383 |
| thermal reference points as an index for monitoring body temperature in marine mammals. | monitoring body temperature is essential in veterinary care as minor variations may indicate dysfunction. rectal temperature is widely used as a proxy for body temperature, but measuring it requires special equipment, training or restraining, and it potentially stresses animals. infrared thermography is an alternative that reduces handling stress, is safer for technicians and works well for untrained animals. this study analysed thermal reference points in five marine mammal species: bottlenose ... | 2015 | 26338544 |
| effect of climatic warming on the pacific walrus, and potential modification of its helminth fauna. | the decreasing extent of sea-ice in the arctic basin as a consequence of climatic warming is modifying the behavior and diets of pagophilic pinnipeds, including the pacific walrus, odobenus rosmarus divergens illiger, the species emphasized here. mammals such as the walrus and bearded seal, erignathus barbatus (erxleben), cannot remain associated with the sea-ice, and continue to feed on their usual diet of benthic invertebrates inhabiting coastal waters to a depth of approximately 100 m, when t ... | 2007 | 18163371 |
| bioaccumulation of persistent organochlorine pesticides (ocps) by gray whale and pacific walrus from the western part of the bering sea. | the feeding habits of a gray whale (eschrichtius robustus) and a pacific walrus (odobenus rosmarus divergens), caught from the western bering sea in the summers of 2010 and 2011, have been studied, and concentration of persistent organochlorine pesticides (ocps) in their organs determined. the total ocp concentration (∑hch+∑ddt) in muscles and liver of the gray whales varies from 297 to 3581 and from 769 to 13,808 ng/g lipids, respectively. the total ocp concentration (∑hch+∑ddt) in muscles and ... | 2015 | 26169228 |
| bioindicators of organochlorine pesticides in the sea of okhotsk and the western bering sea. | organochlorine pesticides (ocps), such as hchs and ddts, are still used as pesticides in the southern hemisphere and can reach the north pacific due to long range atmospheric transfer. marine mammals (pacific walrus odobenus rosmarus divergens, gray whale eschrichtius robustus), the seabirds (pacific gull larus schistisagus, crested auklet aethia cristatella, auklet crumb aethia pusilla, northern fulmar fulmarus glacialis, and grey petrel oceanodroma furcata) and pacific salmon (pink oncorhynchu ... | 2017 | 28528412 |
| growth in pinnipeds. | this review presents summary figures of, and fits growth curves to, data on body lengths (as standard length, sl, whenever possible) of pinnipeds at ages estimated to o.i y. (1) generalized von bertalanffy (vb) growth curves are fitted to most data: lx = l infinity (i - ea(x-x0)b, lx is length at age x, x0 is the origin of the curve (here chosen a priori as time of initiation of embryonic growth), l infinity is asymptotic length, a (which is negative) determines rate of approach to the asymptote ... | 1993 | 8457634 |
| resource partitioning between pacific walruses and bearded seals in the alaska arctic and sub-arctic. | climate-mediated changes in the phenology of arctic sea ice and primary production may alter benthic food webs that sustain populations of pacific walruses (odobenus rosmarus divergens) and bearded seals (erignathus barbatus). interspecific resource competition could place an additional strain on ice-associated marine mammals already facing loss of sea ice habitat. using fatty acid (fa) profiles, fa trophic markers, and fa stable carbon isotope analyses, we found that walruses and bearded seals ... | 2017 | 28550467 |
| accurate recapture identification for genetic mark-recapture studies with error-tolerant likelihood-based match calling and sample clustering. | error-tolerant likelihood-based match calling presents a promising technique to accurately identify recapture events in genetic mark-recapture studies by combining probabilities of latent genotypes and probabilities of observed genotypes, which may contain genotyping errors. combined with clustering algorithms to group samples into sets of recaptures based upon pairwise match calls, these tools can be used to reconstruct accurate capture histories for mark-recapture modelling. here, we assess th ... | 2016 | 28083094 |
| sex-specific energetics of pacific walruses (odobenus rosmarus divergens) during the nursing interval. | habitat use and activity patterns of pacific walruses (odobenus rosmarus divergens) have changed with climate-induced reductions in sea ice. increases in the time active in water could result in negative energy balance, precluding females from sustaining lactation, which could impact population demographics. little is known about lactation costs in walruses. we examined the energetics of 0-2-yr-old walrus calves by using bayesian hierarchical models based on longitudinal husbandry records of gro ... | 2017 | 27082720 |
| pulmonary mast cell tumor and possible paraganglioma in a free-ranging pacific walrus ( odobenus rosmarus divergens), barrow, alaska, usa. | we describe a pulmonary mast cell tumor in a subsistence-harvested free-ranging pacific walrus (odobenus rosmarus divergens). neoplastic cells effacing a focal area of pulmonary parenchyma were characterized by rare metachromatic granules and positive staining for c-kit. we also report co-occurrence of a peribronchial mass with a morphologic and immunohistochemical profile compatible with paraganglioma. | 2016 | 27054472 |
| decadal bering sea seascape change: consequences for pacific walruses and indigenous hunters. | the most significant factors currently affecting the pacific walrus (odobenus rosmarus divergens) population are climate change and consequent changes in sea-ice morphology and dynamics. this paper integrates recent physical sea-ice change in the bering sea with biological and ecological conditions of walruses in their winter-spring reproductive habitat. historically, walrus in winter-spring depended on a critical mass of sea-ice habitat to optimize social networking, reproductive fitness, feedi ... | 2016 | 27039507 |
| rapid maturation of the muscle biochemistry that supports diving in pacific walruses (odobenus rosmarus divergens). | physiological constraints dictate animals' ability to exploit habitats. for marine mammals, it is important to quantify physiological limits that influence diving and their ability to alter foraging behaviors. we characterized age-specific dive limits of walruses by measuring anaerobic (acid-buffering capacity) and aerobic (myoglobin content) capacities of the muscles that power hind (longissimus dorsi) and fore (supraspinatus) flipper propulsion. mean buffering capacities were similar across mu ... | 2015 | 26347559 |
| behavior and body mass changes of a mother and calf pacific walrus (odobenus rosmarus divergens) during the suckling period. | the behavior of a 13-year-old female pacific walrus and her first calf is described during the first 7 months of the 19-month suckling period. the calf vocalized before 62% of suckling sessions. the mother immediately responded after 84% of vocalizations; after 44% she allowed a suckling session. the number of suckling sessions per 24-h period decreased from on average nine in the second week after birth to two by the thirteenth week. thereafter, the number of suckling sessions fluctuated betwee ... | 2015 | 25511011 |
| energy demands for maintenance, growth, pregnancy, and lactation of female pacific walruses (odobenus rosmarus divergens). | decreases in sea ice have altered habitat use and activity patterns of female pacific walruses odobenus rosmarus divergens and could affect their energetic demands, reproductive success, and population status. however, a lack of physiological data from walruses has hampered efforts to develop the bioenergetics models required for fully understanding potential population-level impacts. we analyzed long-term longitudinal data sets of caloric consumption and body mass from nine female pacific walru ... | 2014 | 25461648 |
| pacific walrus (odobenus rosmarus divergens) resource selection in the northern bering sea. | the pacific walrus is a large benthivore with an annual range extending across the continental shelves of the bering and chukchi seas. we used a discrete choice model to estimate site selection by adult radio-tagged walruses relative to the availability of the caloric biomass of benthic infauna and sea ice concentration in a prominent walrus wintering area in the northern bering sea (st. lawrence island polynya) in 2006, 2008, and 2009. at least 60% of the total caloric biomass of dominant macro ... | 2014 | 24717979 |
| coccidioidomycosis in a pacific walrus (odobenus rosmarus divergens). | an 11 yr-old female pacific walrus (odobenus rosmarus divergens) demonstrated decreased appetite and weight loss approximately 4 wk after truck transport from a northern california facility to a southern california facility. an initial blood analysis revealed a leukocytosis of 22,800 white blood cells (wbc)/microl, with a left shift, low iron (58 microg/dl), and mild hyperglobulinemia (4.3 g/dl). empiric antibiotic therapy was started with amoxicillin and clavulanic acid (14 mg/kg p.o. b.i.d.). ... | 2014 | 24712180 |
| underwater passive acoustic localization of pacific walruses in the northeastern chukchi sea. | this paper develops and applies a linearized bayesian localization algorithm based on acoustic arrival times of marine mammal vocalizations at spatially-separated receivers which provides three-dimensional (3d) location estimates with rigorous uncertainty analysis. to properly account for uncertainty in receiver parameters (3d hydrophone locations and synchronization times) and environmental parameters (water depth and sound-speed correction), these quantities are treated as unknowns constrained ... | 2013 | 23968051 |
| estimating age ratios and size of pacific walrus herds on coastal haulouts using video imaging. | during arctic summers, sea ice provides resting habitat for pacific walruses as it drifts over foraging areas in the eastern chukchi sea. climate-driven reductions in sea ice have recently created ice-free conditions in the chukchi sea by late summer causing walruses to rest at coastal haulouts along the chukotka and alaska coasts, which provides an opportunity to study walruses at relatively accessible locations. walrus age can be determined from the ratio of tusk length to snout dimensions. we ... | 2013 | 23936106 |
| pacific walrus and climate change: observations and predictions. | the extent and duration of sea-ice habitats used by pacific walrus (odobenus rosmarus divergens) are diminishing resulting in altered walrus behavior, mortality, and distribution. i document changes that have occurred over the past several decades and make predictions to the end of the 21st century. climate models project that sea ice will monotonically decline resulting in more ice-free summers of longer duration. several stressors that may impact walruses are directly influenced by sea ice. ho ... | 2012 | 22957206 |
| limitations of an optimum sustainable population or potential biological removal approach for conserving marine mammals: pacific walrus case study. | decision rules are the agreed-upon points at which specific management interventions are initiated. for marine mammal management under the u.s. marine mammal protection act (mmpa), decision rules are usually based on either a numeric population or biological-removal approach. however, for walrus and other ice-associated pinnipeds, the inability to reliably assess population numbers or biological removals highlights a significant gap in the mmpa, particularly when the arctic environment is rapidl ... | 2009 | 19783356 |
| the influence of feeding, enrichment, and seasonal context on the behavior of pacific walruses (odobenus rosmarus divergens). | though some research exists concerning general behavior and activity patterns of walruses in zoos or aquariums, less is known about how these patterns change in response to various environmental and temporal contexts. this study presents two studies assessing behavioral changes in relation to feeding period, object enrichment (oe), and season in a social group of four pacific walruses at the new york aquarium. study 1 examined behavior in relation to feeding context (nonfeed, prefeed, postfeed); ... | 2010 | 19722224 |
| feeding enrichment methods for pacific walrus calves. | in the wild, walrus calves are occupied with many behaviors necessary for survival. in captivity there is usually less to occupy them. therefore it is necessary to develop other ways to occupy the animals to prevent negative behavior. in the present study, food in four different types of dispensers were tested on two walrus calves: fish in ice, fish in a nine-hole container, fish in a two-hole container, and fish in ice in a one-hole container. all four methods of offering fish had an effect on ... | 2007 | 19360571 |
| underwater audiogram of a pacific walrus (odobenus rosmarus divergens) measured with narrow-band frequency-modulated signals. | the underwater hearing sensitivity of an 18-year-old male pacific walrus was measured in a pool by using a go/no-go response paradigm and the up-down staircase method. auditory sensitivity was measured using narrow-band, frequency-modulated signals (1500 ms duration) with center frequencies ranging from 0.125 to 15 khz. the resulting underwater audiogram (50% detection thresholds) for this individual walrus shows the typical mammalian u-shape. maximum sensitivity (67 db re 1 micropa) occurred at ... | 2002 | 12430829 |
| atherosclerosis with multifocal myocardial infarction in a pacific walrus (odobenus rosmarus divergens illiger). | a 25-yr-old male captive walrus (odobenus rosmarus divergens illiger) died after suffering from periods of inactivity, anorexia, and weight loss for 8 wk. necropsy revealed prominent, generalized atherosclerosis of cardiac arteries with widespread chronic myocardial infarction. severe disseminated myocardial fibrosis most likely resulted in insidious cardiac failure that was ultimately the cause of death. bouts of abdominal pain and disseminated cutaneous ulcers that had been observed 3 and 4 da ... | 2002 | 12398303 |
| organochlorine compounds and aliphatic hydrocarbons in pacific walrus blubber. | blubber samples were collected from 8 male and 19 female pacific walrus (odobenus rosmarus divergens) taken during a 1991 joint usa/ussr cruise traveling widely through the bering sea. dieldrin was found at a level similar to that reported 10 years earlier; oxychlordane was found at a slightly higher concentration than reported previously (taylor et al, 1989). heptachlor epoxide was detected for the first time and found at a low concentration. an initial testing for alpha-, beta- and gamma-hch d ... | 2013 | 11601530 |
| [prenatal development of the vestibular apparatus in walrus (pinnipedia: odobenidae-odobenus rosmarus divergens)]. | | 1997 | 9376800 |
| prenatal sonography: a useful adjunct in the management of the gravid captive pacific walrus (odobenus rosmarus divergens). | | 1994 | 8083951 |