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sex-specific, seasonal foraging tactics of adult grey seals (halichoerus grypus) revealed by state-space analysis.in many large pelagic animals, observing behavior is limited to observation by radio or satellite telemetry. in many cases, discriminating different behaviors from telemetry data has been a key, but often elusive, goal. here we use state-space models (ssms) to fit a correlated random walk (crw) model that switches between two unobserved behavioral states (nominally foraging and traveling) to 41 male and 43 female adult grey seal (halichoerus grypus) satellite telemetry tracks. the ssm results re ...200919967876
relationships between vitamin a and pcbs in grey seal mothers and pups during lactation.a previous study has shown a simultaneous increase of vitamin a and pcbs in grey seal (halichoerus grypus) milk at late lactation (debier et al., 2004). here we sought to understand this unexpected relationship by comparing the dynamics of vitamin a and pcbs in the different tissue compartments of transfer. lactating grey seals and their pups were sampled longitudinally in scotland during the 2006 breeding season. as blubber reserves decreased, concentrations of vitamin a and pcbs increased duri ...201020064681
mortality trends of stranded marine mammals on cape cod and southeastern massachusetts, usa, 2000 to 2006.to understand the cause of death of 405 marine mammals stranded on cape cod and southeastern massachusetts between 2000 and 2006, a system for coding final diagnosis was developed and categorized as (1) disease, (2) human interaction, (3) mass-stranded with no significant findings, (4) single-stranded with no significant findings, (5) rock and/or sand ingestion, (6) predatory attack, (7) failure to thrive or dependent calf or pup, or (8) other. the cause of death for 91 animals could not be dete ...201020225675
the identification of a new giardia duodenalis assemblage in marine vertebrates and a preliminary analysis of g. duodenalis population biology in marine systems.giardia duodenalis is an intestinal parasite of many vertebrates. the presence of g. duodenalis in the marine environment due to anthropogenic and wildlife activity is well documented, including the contributions from untreated sewage and storm water, agricultural run-off and droppings from terrestrial animals. recently, studies have detected this protistan parasite in the faeces of marine vertebrates such as whales, dolphins, seals and shore birds. to explore the population biology of g. duoden ...201020361967
using gps data to evaluate the accuracy of state-space methods for correction of argos satellite telemetry error.recent studies have applied state-space models to satellite telemetry data in order to remove noise from raw location estimates and infer the true tracks of animals. however, while the resulting tracks may appear plausible, it is difficult to determine the accuracy of the estimated positions, especially for position estimates interpolated to times between satellite locations. in this study, we use data from two gray seals (halichoerus grypus) carrying tags that transmitted fastloc gps positions ...201020380216
aversiveness of sounds in phocid seals: psycho-physiological factors, learning processes and motivation.aversiveness of sounds and its underlying physiological mechanisms in mammals are poorly understood. in this study we tested the influence of psychophysical parameters, motivation and learning processes on the aversiveness of anthropogenic underwater noise in phocid seals (halichoerus grypus and phoca vitulina). we compared behavioural responses of seals to playbacks of sounds based on a model of sensory unpleasantness for humans, sounds from acoustic deterrent devices and sounds with assumed ne ...201020400639
blood cell composition of gray seals of different ages. 201620665155
effects of age and body mass on development of diving capabilities of gray seal pups: costs and benefits of the postweaning fast.development of adequate diving capabilities is crucial for survival of seal pups and may depend on age and body size. we tracked the diving behavior of 20 gray seal pups during their first 3 mo at sea using satellite relay data loggers. we employed quantile analysis to track upper limits of dive duration and percentage time spent diving, and lower limits of surface intervals. when pups first left the breeding colony, extreme (ninety-fifth percentile) dive duration and percentage time spent divin ...201020969447
pbdes in serum and blubber of harbor, grey and harp seal pups from eastern canada.serum and blubber of pup harbor (phoca vitulina), grey (halichoerus grypus) and harp (phoca groenlandica) seals from the estuary and the gulf of st. lawrence were analyzed for polybrominated diphenyl ethers (pbdes). concentrations of ∑pbdes (on lipid weight basis) in tissues of harbor seal pups inhabiting the st. lawrence estuary were about five times higher than in those from a colony located in the northern gulf. harp seal pups have the lowest levels of ∑pbdes among the seal species born in th ...201021112068
geographic variation of the major histocompatibility complex in eastern atlantic grey seals (halichoerus grypus).pathogen-driven balancing selection maintains high genetic diversity in many vertebrates, particularly in the major histocompatibility complex (mhc) immune system gene family, which is often associated with disease susceptibility. in large natural populations where subpopulations face different pathogen pressures, the mhc should show greater genetic differentiation within a species than neutral markers. we examined genetic diversity at the mhc-dqb locus and nine putatively neutral microsatellite ...201021199032
seroprevalence of toxoplasma gondii in north-eastern atlantic harbor seal (phoca vitulina vitulina) and grey seal (halichoerus grypus).antibodies to toxoplasma gondii were determined in serum samples from 47 grey seals (halichoerus grypus) and 56 harbor seals (phoca vitulina vitulina) from the atlantic coasts of united kingdom and france. antibodies to t. gondii assayed by the modified agglutination test (mat) were found in 14 (13.6%; ic(95%): 7.0-20.2) of 103 seals tested, with titres of 1:25 in 13 seals and 1:50 in 1 seal. seroprevalence against t. gondii (mat 1:25 or higher) was significantly higher in grey seals (23.4%) com ...201121330059
zona pellucida-based contraceptive vaccines for human and animal utility.contraceptive vaccines can be designed to inhibit (i) production of the gametes (sperm and oocyte), (ii) functions of gametes leading to block in fertilization, and (iii) the gamete outcome (pregnancy). the zona pellucida (zp) glycoproteins have been proposed as candidates for developing contraceptive vaccines by virtue of their critical role in fertilization. immunization of non-human primates with either native or recombinant zp proteins leads to curtailment of fertility, which however is inva ...201121377213
detecting density dependence in recovering seal populations.time series of abundance estimates are commonly used for analyses of population trends and possible shifts in growth rate. we investigate if trends in age composition can be used as an alternative to abundance estimates for detection of decelerated population growth. both methods were tested under two forms of density dependence and different levels of environmental variation in simulated time series of growth in baltic gray seals. under logistic growth, decelerating growth could be statisticall ...201121404823
the occurrence of mycoplasma phocicerebrale, mycoplasma phocidae, and mycoplasma phocirhinis in grey and common seals (halichoerus grypus and phoca vitulina) in the united kingdom.following the isolation of mycoplasma phocicerebrale from the flipper wound of a grey seal (halichoerus grypus) in cornwall, uk, surveillance for mycoplasma species was extended to include other seals rescued or found dead around the uk. mycoplasma phocicerebrale was frequently detected from the teeth of seals and from infected wounds and respiratory tracts. mycoplasma phocirhinis, mycoplasma phocidae, and some unidentified mycoplasma species were also detected. mycoplasma phocicerebrale and m. ...201121441202
repeated elicitation of the acoustic startle reflex leads to sensitisation in subsequent avoidance behaviour and induces fear conditioning.abstract:201121489285
trichinella nativa in grey seal halichoerus grypus - spill-over from a highly endemic terrestrial ecosystem.abstract trichinella infections of marine mammals pose a human health risk in arctic regions where game meat is important part of the diet. in the last decade, the grey seal population of the subarctic baltic sea has reached a level at which hunting is possible and seal meat is now available for food. we conducted a survey on the occurrence of trichinella spp. in grey seals halichoerus grypus (n = 171) and ringed seals phoca hispida botnica (n = 56) of the baltic sea in the coastal waters of fin ...201121506828
effect of induction dose, lactation stage and body condition on tiletamine-zolazepam anaesthesia in adult female grey seals (halichoerus grypus) under field conditions.tiletamine-zolazepam (tz) was used at a mean (sd) dose of 1.18 (0.15) mg/kg administered intramuscularly to anaesthetise adult female grey seals (halichoerus grypus) under field conditions at three different stages during their lactation period. a significant correlation was observed between the induction dose and time to induction (r=-0.582, p=0.011). stage of lactation had a significant effect on condition index (ci), calculated as axial girth divided by length (p<0.001), and time to induction ...201121508066
molecular methods for differentiating grey seal (halichoerus grypus) and harbour seal (phoca vitulina) scat.pinniped dietary information is crucial for understanding marine ecosystems; however, in the north atlantic, grey and harbour seals haulout concomitantly and their faeces are visually indistinguishable. therefore, we developed molecular methods to differentiate the species' scat. pcr primers were created that amplify a portion of mitochondrial 16s ribosomal dna in grey and harbour seals. the samples were amplified and the resulting products were digested using the restriction enzyme tsp509i, pro ...201021565013
could seals prevent cod recovery in the baltic sea?fish populations are increasingly affected by multiple human and natural impacts including exploitation, eutrophication, habitat alteration and climate change. as a result many collapsed populations may have to recover in ecosystems whose structure and functioning differ from those in which they were formerly productive and supported sustainable fisheries. here we investigate how a cod (gadus morhua) population in the baltic sea whose biomass was reduced due to a combination of high exploitation ...201121573062
the influence of reproductive experience on milk energy output and lactation performance in the grey seal (halichoerus grypus).although evidence from domestic and laboratory species suggests that reproductive experience plays a critical role in the development of aspects of lactation performance, whether reproductive experience may have a significant influence on milk energy transfer to neonates in wild populations has not been directly investigated. we compared maternal energy expenditures and pup growth and energy deposition over the course of lactation between primiparous and fully-grown, multiparous grey seal (halic ...201121589918
Temporal trends of polyfluoroalkyl compounds (PFCs) in liver tissue of grey seals (Halichoerus grypus) from the Baltic Sea, 1974-2008.Temporal trends of polyfluoroalkyl compounds (PFCs) were examined in grey seal (Halichoerus grypus) liver from the Baltic Sea over a period of 35years (1974-2008). In total, 17 of 43 PFCs were found, including the perfluoroalkyl sulfonates (C(4)-C(10) PFSAs), perfluorooctanesulfinate (PFOSi), long chain perfluoroalkyl carboxylates (C(7)-C(14) PFCAs), and perfluoroalkyl sulfonamides (i.e., perfluorooctane sulfonamide (FOSA) and N-ethyl perfluorooctane sulfonamide (EtFOSA)), whereas saturated and ...201121680009
hyperbaric computed tomographic measurement of lung compression in seals and dolphins.lung compression of vertebrates as they dive poses anatomical and physiological challenges. there has been little direct observation of this. a harbor and a gray seal, a common dolphin and a harbor porpoise were each imaged post mortem under pressure using a radiolucent, fiberglass, water-filled pressure vessel rated to a depth equivalent of 170 m. the vessel was scanned using computed tomography (ct), and supported by a rail and counterweighted carriage magnetically linked to the ct table movem ...201121697431
anaesthesia of three young grey seals (halichoerus grypus) for fracture repair.abstract: three young grey seals (halichoerus grypus) were presented separately for fracture repair to the veterinary teaching hospital of university college dublin. the seals were premedicated with a combination of pethidine, midazolam and atropine; anaesthesia was induced with propofol via the front flipper vein and maintained with sevoflurane or isoflurane in oxygen. one of the seals did not breathe spontaneously after anaesthesia; a cardiac arrest, resulting in death, occurred after several ...201121777490
interacting trophic forcing and the population dynamics of herring.small pelagic fish occupy a central position in marine ecosystems worldwide, largely by determining the energy transfer from lower trophic levels to predators at the top of the food web, including humans. population dynamics of small pelagic fish may therefore be regulated neither strictly bottom-up nor top-down, but rather through multiple external and internal drivers. while in many studies single drivers have been identified, potential synergies of multiple factors, as well as their relative ...201121870614
naso-pharyngeal mites halarachne halichoeri (allman, 1847) in grey seals stranded on the nw spanish atlantic coast.in north atlantic european waters, the nasal mite halarachne halichoeri has been described affecting grey seals (halichoerus grypus) producing different levels of respiratory disease. this study provides data on the prevalence, clinical signs and produced macro-pathology of this parasite mite infecting juvenile wild grey seals stranded in north-western spanish coast. among the 25 seals examined during the study, a total of 19 had nasal mites in their respiratory upper ways, including adult and l ...201221871735
reprint of: temporal trends of polyfluoroalkyl compounds (pfcs) in liver tissue of grey seals (halichoerus grypus) from the baltic sea, 1974-2008.temporal trends of polyfluoroalkyl compounds (pfcs) were examined in grey seal (halichoerus grypus) liver from the baltic sea over a period of 35 years (1974-2008). in total, 17 of 43 pfcs were found, including the perfluoroalkyl sulfonates (c(4)-c(10) pfsas), perfluorooctanesulfinate (pfosi), long chain perfluoroalkyl carboxylates (c(7)-c(14) pfcas), and perfluoroalkyl sulfonamides (i.e., perfluorooctane sulfonamide (fosa) and n-ethyl perfluorooctane sulfonamide (etfosa)), whereas saturated and ...201121944042
Effects of handling regime and sex on changes in cortisol, thyroid hormones and body mass in fasting grey seal pups.Survival of seal pups may be affected by their ability to respond appropriately to stress. Chronic stress can adversely affect secretion of cortisol and thyroid hormones, which contribute to the control of fuel utilisation. Repeated handling could disrupt the endocrine response to stress and/or negatively impact upon mass changes during fasting. Here we investigated the effects of handling regime on cortisol and thyroid hormone levels, and body mass changes, in fasting male and female grey seal ...201221945943
static inflation and deflation pressure-volume curves from excised lungs of marine mammals.excised lungs from eight marine mammal species [harp seal (pagophilus groenlandicus), harbor seal (phoca vitulina), gray seal (halichoerus grypush), atlantic white-sided dolphin (lagenorhynchus acutus), common dolphin (delphinus delphis), risso's dolphin (grampus griseus), long-finned pilot whale (globicephala melas) and harbor porpoise (phocoena phocoena)] were used to determine the minimum air volume of the relaxed lung (mav, n=15), the elastic properties (pressure-volume curves, n=24) of the ...201122031747
Indications for both host-specific and introduced genotypes of Staphylococcus aureus in marine mammals.Staphylococcus aureus is present in the marine environment and causes disease in marine mammals. To determine whether marine mammals are colonized by host-specific strains or by strains originating from other species, we performed multi-locus sequence typing on ten S. aureus strains isolated from marine mammals in the U.K., the Netherlands, and the Antarctic. Four new sequence types of S. aureus were discovered. S. aureus strains from a southern elephant seal (n=1) and harbour porpoises (n=2) di ...201122112853
likely effects of construction of scroby sands offshore wind farm on a mixed population of harbour phoca vitulina and grey halichoerus grypus seals.scroby sands offshore wind farm was built close to a haul-out and breeding site for harbour seal, a species of conservation concern. an aerial survey programme conducted during a five-year period spanning wind farm construction, revealed a significant post-construction decline in haul-out counts. multivariate model selection suggested that the decline was not related to the environmental factors considered, nor did it mirror wider population trends. although cause and effect could not be unequiv ...201222333892
fused traditional and geometric morphometrics demonstrate pinniped whisker diversity.vibrissae (whiskers) are important components of the mammalian tactile sensory system, and primarily function as detectors of vibrotactile information from the environment. pinnipeds possess the largest vibrissae among mammals and their vibrissal hair shafts demonstrate a diversity of shapes. the vibrissae of most phocid seals exhibit a beaded morphology with repeating sequences of crests and troughs along their length. however, there are few detailed analyses of pinniped vibrissal morphology, a ...201222509310
phocid seal leptin: tertiary structure and hydrophobic receptor binding site preservation during distinct leptin gene evolution.the cytokine hormone leptin is a key signalling molecule in many pathways that control physiological functions. although leptin demonstrates structural conservation in mammals, there is evidence of positive selection in primates, lagomorphs and chiropterans. we previously reported that the leptin genes of the grey and harbour seals (phocids) have significantly diverged from other mammals. therefore we further investigated the diversification of leptin in phocids, other marine mammals and terrest ...201222536379
patterns of stranding and mortality in common seals (phoca vitulina) and grey seals (halichoerus grypus) in the netherlands between 1979 and 2008.pathological examination of stranded marine mammals provides information on the causes of mortality in their populations. patterns of stranding and causes of death of dead-stranded seals on the dutch coast were analyzed over a 30-year period (1979-2008). stranding data (n=1,286) and post-mortem data (n=379) from common seals (phoca vitulina) and grey seals (halichoerus grypus) found dead, or that died before admission to rehabilitation, were obtained from the seal rehabilitation and research cen ...201222632685
selective transfer of persistent organic pollutants and their metabolites in grey seals during lactation.twenty grey seal (halichoerus grypus) mother-pup pairs from the colony of the isle of may (scotland) were sampled at early and late lactation in order to study the transfer of polychlorinated biphenyls (pcbs), polybrominated diphenyl ethers (pbdes) and their metabolites (ho-pcbs and ho-pbdes) as well as organochlorine pesticides (ocps), such as ddt and metabolites (ddxs) and hexachlorobenzene (hcb). the transfer of the naturally produced meo-pbdes was also investigated. generally, concentrations ...201222659007
emerging pseudoterranova decipiens (krabbe, 1878) problems in baltic cod, gadus morhua l., associated with grey seal colonization of spawning grounds. 201222817526
primiparous and multiparous females differ in mammary gland alveolar development: implications for milk production.mammary gland capacity is influenced by the number of secretory cells in the gland, the activity of those cells and the size and arrangement of the alveoli that they form. although reproductive experience has been shown to affect the total number of secretory cells in the gland, its potential effect on the structural development of lobulo-alveolar tissues has not been directly investigated. to examine whether reproductive experience affects lobulo-alveolar development, we took mammary gland biop ...201222837465
improved reproductive success in otters (lutra lutra), grey seals (halichoerus grypus) and sea eagles (haliaeetus albicilla) from sweden in relation to concentrations of organochlorine contaminants.we studied indices of reproductive outcome in three aquatic species in relation to organochlorine concentrations during four decades. in female otters, the frequency of signs of reproduction increased after 1990. in grey seals, pregnancy rate increased 1990-2010 and uterine obstructions ceased after 1993. the frequency of uterine tumours was highest 1980-2000. the number of sea eagle nestlings per checked nest increased 1985-2000, while the frequency of desiccated eggs decreased. organochlorine ...201222842056
mhc genotype and near-deterministic mortality in grey seals.the major histocompatability complex (mhc) is one of the best known and best characterised components of the immune system, yet its functions remain somewhat enigmatic, including both anti-pathogen activity and kin recognition. to explore the importance of the mhc relative to literally hundreds of other components of the immune system, we compared mhc genotype frequencies between pups and adults in the grey seal (halichoerus grypus), one of many marine mammals that exhibit low allelic diversity. ...201222997548
natural selection on marine carnivores elaborated a diverse family of classical mhc class i genes exhibiting haplotypic gene content variation and allelic polymorphism.pinnipeds, marine carnivores, diverged from terrestrial carnivores ~45 million years ago, before their adaptation to marine environments. this lifestyle change exposed pinnipeds to different microbiota and pathogens, with probable impact on their mhc class i genes. investigating this question, genomic sequences were determined for 71 mhc class i variants: 27 from harbor seal and 44 from gray seal. these variants form three mhc class i gene lineages, one comprising a pseudogene. the second, a can ...201223001684
changes in trace elements during lactation in a marine top predator, the grey seal.lactation in pinnipeds represents the most significant cost to mothers during the reproductive cycle. dynamics of trace elements and their mobilization associated with energy reserves during such an intense physiological process remains poorly understood in marine mammals. the changes in tissue concentrations of 11 elements (ca, cd, cr, cu, fe, hg, ni, pb, se, v, and zn) were investigated in a longitudinal study during the lactation period and during the post-weaning fast period. blood, milk, bl ...201323010392
sink fast and swim harder! round-trip cost-of-transport for buoyant divers.efficient locomotion between prey resources at depth and oxygen at the surface is crucial for breath-hold divers to maximize time spent in the foraging layer, and thereby net energy intake rates. the body density of divers, which changes with body condition, determines the apparent weight (buoyancy) of divers, which may affect round-trip cost-of-transport (cot) between the surface and depth. we evaluated alternative predictions from external-work and actuator-disc theory of how non-neutral buoya ...201223014571
canid progesterone receptors lack activation function 3 domain-dependent activity.progesterone regulates multiple behavioral, physiological, and pathological aspects of female reproductive biology through its two progesterone receptors (prs), pr-b and the truncated pr-a. pr-b is necessary for mammary gland development in mice and, compared with pr-a, is overall a stronger transactivator of target genes due to an additional activation function 3 (af3) domain. in dogs, known for their high sensitivity to progesterone-induced mammary cancer, the pr-b function was studied. canine ...201223041671
effects of polychlorobiphenyls, polybromodiphenylethers, organochlorine pesticides and their metabolites on vitamin a status in lactating grey seals.polychlorobiphenyls (pcbs), polybromodiphenylethers (pbdes) and organochlorine pesticides (ocps), such as dichlorodiphenyltrichloroethane (ddt) and hexachlorobenzene (hcb), are considered as endocrine disruptors in laboratory and wild animals. this study investigated whether these compounds and their hydroxylated metabolites (ho-pcbs and ho-pbdes) may affect the homoeostasis of vitamin a, a dietary hormone, in the blubber and serum of twenty lactating grey seals sampled at early and late lactati ...201323051620
entanglement of grey seals halichoerus grypus at a haul out site in cornwall, uk.entanglement in marine debris has been internationally recognised as a potential threat to marine species. sightings records and a photo identification catalogue from a haul out site in southwest england were used to establish entanglement records for grey seals halichoerus grypus. between 2004 and 2008 the annual mean entanglement rates varied from 3.6% to 5%. the maximum recapture period for entangled seals compared to paired control seals was significantly less (p=0.045) suggesting an increas ...201223117201
surgical repair of a tibial fracture in a two-week-old grey seal (halichoerus grypus).to report the successful management of a suspected infected tibial fracture in a common grey seal.201323154822
animal-borne acoustic transceivers reveal patterns of at-sea associations in an upper-trophic level predator.satellite telemetry data have substantially increased our understanding of habitat use and foraging behaviour of upper-trophic marine predators, but fall short of providing an understanding of their social behaviour. we sought to determine whether novel acoustic and archival gps data could be used to examine at-sea associations among grey seals (halichoerus grypus) during the fall foraging period. fifteen grey seals from sable island, canada were deployed with vemco mobile transceivers and satel ...201223155435
variation in female grey seal (halichoerus grypus) reproductive performance correlates to proactive-reactive behavioural types.consistent individual differences (cids) in behaviour, indicative of behavioural types or personalities, have been shown in taxa ranging from cnidaria to mammalia. however, despite numerous theoretical explanations there remains limited empirical evidence for selective mechanisms that maintain such variation within natural populations. we examined behavioural types and fitness proxies in wild female grey seals at the north rona breeding colony. experiments in 2009 and 2010 employed a remotely-co ...201223166723
cyclic volatile methylsiloxanes in fish from the baltic sea.laboratory studies suggest that the cyclic volatile methylsiloxanes (cvms) octamethylcyclotetrasiloxane (d4), decamethylcyclopentasiloxane (d5) and dodecamethylcyclohexasiloxane (d6) will persist in the aquatic environment and bioaccumulate in fish. here these cvms were measured in herring collected in the swedish waters of the baltic sea and the north sea and in grey seals from the baltic proper. d4, d5, and d6 were present in herring muscle at concentrations around 10, 200, and 40ngg(-1) lipid ...201323177719
the role of glucocorticoids in naturally fasting grey seal (halichoerus grypus) pups: dexamethasone stimulates mass loss and protein utilisation, but not departure from the colony.seals must manage their energy reserves carefully while they fast on land to ensure that they go to sea with sufficient fuel to sustain them until they find food. glucocorticoids (gcs) have been implicated in the control of fuel metabolism and termination of fasting in pinnipeds. here we tested the hypothesis that dexamethasone, an artificial gc, increases fat and protein catabolism, and induces departure from the breeding colony in wild, fasting grey seal pups. a single intramuscular dose of de ...201323197086
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
how many seals were there? the global shelf loss during the last glacial maximum and its effect on the size and distribution of grey seal populations.predicting how marine mammal populations respond to habitat changes will be essential for developing conservation management strategies in the 21st century. responses to previous environmental change may be informative in the development of predictive models. here we describe the likely effects of the last ice age on grey seal population size and distribution. we use satellite telemetry data to define grey seal foraging habitat in terms of the temperature and depth ranges exploited by the contem ...201223300843
human streptococcus agalactiae strains in aquatic mammals and fish.in humans, streptococcus agalactiae or group b streptococcus (gbs) is a frequent coloniser of the rectovaginal tract, a major cause of neonatal infectious disease and an emerging cause of disease in non-pregnant adults. in addition, streptococcus agalactiae causes invasive disease in fish, compromising food security and posing a zoonotic hazard. we studied the molecular epidemiology of s. agalactiae in fish and other aquatic species to assess potential for pathogen transmission between aquatic s ...201323419028
detection of canine distemper virus serum neutralizing antibodies in captive u.s. phocids.antibodies to morbilliviruses have been documented in free-ranging pinnipeds throughout populations in the atlantic and arctic oceans, but not from the pacific ocean. as a symbolic geographic barrier between the exposed atlantic and naive pacific populations, the captive phocid population in north america had undocumented serologic status. in this study, canine distemper virus (cdv) serum neutralization assays were used to assess the prevalence of antibodies in this population with participation ...201323505705
imaging diagnosis-ultrasonographic and ct findings in a gray seal (halichoerus grypus) with hepatic cirrhosis, pyelonephritis, and nephrolithiasis.an immature gray seal was presented with lethargy, weight loss, vomiting and hematuria. hepatic disease and urinary tract infection were suspected. abdominal ultrasound showed hyperechoic structures with marked acoustic shadowing spread throughout both kidneys, but incomplete visualization of the liver. abdominal ct showed mineral densities scattered throughout both kidneys and poor delineation of the liver. due to the poor quality of life, the seal was euthanized. postmortem examination showed ...201623578275
habitat-mediated dive behavior in free-ranging grey seals.understanding the links between foraging behaviour and habitat use of key species is essential to addressing fundamental questions about trophic interactions and ecosystem functioning. eight female grey seals (halichoerus grypus) were equipped with time-depth recorders linked to fastloc gps tags following the annual moult in southwest ireland. individual dives were coupled with environmental correlates to investigate the habitat use and dive behaviour of free-ranging seals. dives were characteri ...201323667663
liver glucose-6-phosphatase proteins in suckling and weaned grey seal pups: structural similarities to other mammals and relationship to nutrition, insulin signalling and metabolite levels.phocid seals have been proposed as models for diabetes because they exhibit limited insulin response to glucose, high blood glucose and increasing insulin resistance when fasting. liver glucose-6-phosphatase (g6pase) catalyses the final step in glucose production and is central to glucose regulation in other animals. g6pase comprises a translocase (slc37a4) and a catalytic subunit (g6pc). g6pc and slc37a4 expression and activity are normally regulated by nutritional state and glucostatic hormone ...201323743798
mycobacterium bovis infection in a grey seal pup (halichoerus grypus). 201323764843
selective blubber fatty acid mobilization in lactating gray seals (halichoerus grypus).during negative energy balance periods, fatty acids (fas) are mobilized to cover the metabolic demands of the body. fas from adipose tissue are selectively mobilized according to their carbon length (cl) and number of double bonds (dbs); however, studies in vivo have focused only on fasting and nonlactating animals. during lactation, uk gray seals fast for 18 d, mobilizing a large amount of lipid from blubber to sustain their own metabolic demands and the nutritional requirements of pups. we inv ...201323799838
the use of non destructive biomarkers in the study of marine mammals.marine mammals have been subject to heavy anthropogenic pressure by direct killing and chemical pollution all over the world. most studies of contamination and biomarker responses in marine mammals have been conducted using animals killed by hunting out of a total of 12 cetacean species studied, 45 of the specimens were obtained by sacrificing the animal; out of a total of eight pinniped species studied, 40 of the specimens were obtained by killing. the development of a series of non destructive ...199723899212
control control control: a reassessment and comparison of genbank and chromatogram mtdna sequence variation in baltic grey seals (halichoerus grypus).genetic data can provide a powerful tool for those interested in the biology, management and conservation of wildlife, but also lead to erroneous conclusions if appropriate controls are not taken at all steps of the analytical process. this particularly applies to data deposited in public repositories such as genbank, whose utility relies heavily on the assumption of high data quality. here we report on an in-depth reassessment and comparison of genbank and chromatogram mtdna sequence data gener ...201323977362
effects of a large northern european no-take zone on flatfish populations.in march 2006, a 360 km² no-take zone (ntz) was established north of gotland in the central baltic sea, with the purpose to scientifically evaluate the effects of a fishing ban on flatfish populations. a monitoring programme was set up to study the populations in the ntz and in a reference area east of gotland where the fishing pressure was high. the programme included fishing with multimesh survey nets, modelling of potential larval export and estimation of fish consumption by large marine pred ...201324090556
behavioral signature of intraspecific competition and density dependence in colony-breeding marine predators.in populations of colony-breeding marine animals, foraging around colonies can lead to intraspecific competition. this competition affects individual foraging behavior and can cause density-dependent population growth. where behavioral data are available, it may be possible to infer the mechanism of intraspecific competition. if these mechanics are understood, they can be used to predict the population-level functional response resulting from the competition. using satellite relocation and dive ...201324198943
a study on the effect of different rifle calibres in euthanisation of grey seals (halichoerus grypus) in seal traps in the baltic sea.in recent years, the euthanasia of seals has been discussed internationally and concern has been raised regarding the use of rifles, the effect of different calibres, and which calibres are sufficient for humane euthanasia. this study therefore investigated the effect of different firearm calibres on euthanasia of grey seals (halichoerus grypus) in traps, and provides information for the development and refinement of regulations for hunting seals in the wild.201324219864
human pathogens in marine mammal meat – a northern perspective.only a few countries worldwide hunt seals and whales commercially. in norway, hooded and harp seals and minke whales are commercially harvested, and coastal seals (harbour and grey seals) are hunted as game. marine mammal meat is sold to the public and thus included in general microbiological meat control regulations. slaughtering and dressing of marine mammals are performed in the open air on deck, and many factors on board sealing or whaling vessels may affect meat quality, such as the ice use ...201424344685
behavioral responses by grey seals (halichoerus grypus) to high frequency sonar.the use of high frequency sonar is now commonplace in the marine environment. most marine mammals rely on sound to navigate, and for detecting prey, and there is the potential that the acoustic signals of sonar could cause behavioral responses. to investigate this, we carried out behavioral response tests with grey seals to two sonar systems (200 and 375 khz systems). results showed that both systems had significant effects on the seals behavior; when the 200 khz sonar was active, seals spent si ...201424445129
clinical challenge: systemic rhizopus microsporus infection with renal cavitation in a grey seal (halichoerus grypus). 201324450087
the use of dna barcoding to monitor the marine mammal biodiversity along the french atlantic coast.in the last ten years, 14 species of cetaceans and five species of pinnipeds stranded along the atlantic coast of brittany in the north west of france. all species included, an average of 150 animals strand each year in this area. based on reports from the stranding network operating along this coast, the most common stranding events comprise six cetacean species (delphinus delphis, tursiops truncatus, stenella coeruleoalba, globicephala melas, grampus griseus, phocoena phocoena)and one pinniped ...201324453548
validation of an enzyme-linked immunoassay (elisa) for plasma oxytocin in a novel mammal species reveals potential errors induced by sampling procedure.the neuropeptide oxytocin is increasingly the focus of many studies investigating human and animal social behaviours and diseases. however, interpretation and comparison of results is made difficult by a lack of consistent methodological approaches towards analysing this hormone.201424485867
anisakids of seals found on the southern coast of baltic sea.in the present study 5 grey seals (halichoerus grypus), 3 common seals (phoca vitulina) and 1 ringed seal (pusa hispida) bycaught or stranded on the polish baltic sea coast in years 2000-2006 were investigated for the infestation of parasitic anisakid nematodes. 749 of anisakids were found. the most common were: contracaecum osculatum (59.3%) and pseudoterranova decipiens (31.0%). there were also small numbers of anisakis simplex (0.8%). after performing rflp three sibling species were found. c. ...201424570064
in-air evoked potential audiometry of grey seals (halichoerus grypus) from the north and baltic seas.in-air anthropogenic sound has the potential to affect grey seal (halichoerus grypus) behaviour and interfere with acoustic communication. in this study, a new method was used to deliver acoustic signals to grey seals as part of an in-air hearing assessment. using in-ear headphones with adapted ear inserts allowed for the measurement of auditory brainstem responses (abr) on sedated grey seals exposed to 5-cycle (2-1-2) tone pips. thresholds were measured at 10 frequencies between 1-20 khz. measu ...201424632891
increased contracaecum osculatum infection in baltic cod (gadus morhua) livers (1982-2012) associated with increasing grey seal (halichoerus gryphus) populations.grey seals (halichoerus gryphus), the main final host of the gastric parasitic nematode contracaecum osculatum in the baltic, have recently recolonized the southwestern baltic sea. this colonization could lead to an increase in prevalence and intensity of third-stage larvae of c. osculatum in livers of baltic cod (gadus morhua), which serve as transport host for this helminth. we performed a parasitologic study of cod in spring 2012 and compared the results with previously unpublished data from ...201424779467
validation of a commercial canine assay kit to measure pinniped cytokines.the present study was conducted to assess and validate the cross-reactivity of commercially available multiplex human and canine cytokine kits coupled with the bio-plex 200 platform to measure cytokines in three pinniped species, harbor seals (phoca vitulina), gray seals (halichoerus grypus), and harp seals (pagophilus groenlandicus). cytokines are important small proteins that help direct a proper immune response to pathogens. the human cytokine kit allowed the detection of cytokines in the sup ...201424845148
probability of detecting marine predator-prey and species interactions using novel hybrid acoustic transmitter-receiver tags.understanding the nature of inter-specific and conspecific interactions in the ocean is challenging because direct observation is usually impossible. the development of dual transmitter/receivers, vemco mobile transceivers (vmt), and satellite-linked (e.g. gps) tags provides a unique opportunity to better understand between and within species interactions in space and time. quantifying the uncertainty associated with detecting a tagged animal, particularly under varying field conditions, is vita ...201424892286
global population structure and demographic history of the grey seal.although the grey seal halichoerus grypus is one of the most familiar and intensively studied of all pinniped species, its global population structure remains to be elucidated. little is also known about how the species as a whole may have historically responded to climate-driven changes in habitat availability and anthropogenic exploitation. we therefore analysed samples from over 1500 individuals collected from 22 colonies spanning the western and eastern atlantic and the baltic sea regions, r ...201425041117
an optimized computed tomography protocol for metallic gunshot head trauma in a seal model.computed tomography (ct) is commonly used to assess animals with head trauma. however, strongly attenuating objects such as metallic gunshot cause artifacts that may make accurate localization of shrapnel pieces difficult. the purpose of this study was to develop an optimized ct protocol for minimizing metal artifacts in an animal model of gunshot head trauma. a cadaver head of a stranded gray seal (halichoerus grypus) was shot post-mortem with a 0.223-inch caliber rifle. the head was frozen, th ...201625184173
molecular biomarkers in grey seals (halichoerus grypus) to evaluate pollutant exposure, health and immune status.grey seals as top-predators bioaccumulate contaminants and can be considered as sentinels of eco-system health. pups are weaned after a short nursing period, characterised by an enormous lipid transfer and exposure to contaminants. this study established molecular biomarkers of the xenobiotic metabolism and immune system to help assess health and immune status. mrna transcription of ahr, arnt, pparα and cytokine il-2 and heat-shock-protein hsp70 was measured in blood of grey seal pups and adults ...201425220314
occurrence of zoonotic nematodes pseudoterranova decipiens, contracaecum osculatum and anisakis simplex in cod (gadus morhua) from the baltic sea.baltic cod gadus morhua (a total of total 224 specimens) captured east of the island of bornholm in the southern baltic sea were subjected to a parasitological investigation between march 2013 and april 2014. full artificial digestion of fillets from 188 cod and additional investigation of livers from 36 cod were performed. cod or seal worm pseudoterranova decipiens was recorded in musculature (prevalences up to 55% and intensities up to 56 worms per fish) associated with a negative correlation ...201425224792
hsp70 abundance and antioxidant capacity in feeding and fasting gray seal pups: suckling is associated with higher levels of key cellular defenses.heat shock proteins (hsps) and antioxidants are key cellular defenses against stress. seals routinely undergo protracted fasting, which is normally associated with physiological stress in other animals. we tested the hypotheses that (1) relative hsp70 protein abundance is higher in liver and blubber of fasting relative to suckling wild gray seal pups; (2) differences in hsp70 are mirrored in tissue superoxide dismutase (sod) and catalase activity, as well as glutathione levels; (3) extracellular ...201425244378
sealworm (pseudoterranova decipiens) infection in grey seals (halichoerus grypus), cod (gadus morhua) and shorthorn sculpin (myoxocephalus scorpius) in the baltic sea.the anisakid nematode pseudoterranova decipiens, known as the sealworm or cod worm, can infect the flesh of several fish species. the parasite causes cosmetic problems for the fish industry and can cause abdominal discomfort if consumed by humans. there are only scattered studies on the abundance or distribution of the sealworm in fish and seals in the baltic sea. to remedy this situation, the extent of sealworm infection was investigated in cod (gadus morhua) and shorthorn sculpin (myoxocephalu ...201525367209
molecular epidemiology of seal parvovirus, 1988-2014.a novel parvovirus was discovered recently in the brain of a harbor seal (phoca vitulina) with chronic meningo-encephalitis. phylogenetic analysis of this virus indicated that it belongs to the genus erythroparvovirus, to which also human parvovirus b19 belongs. in the present study, the prevalence, genetic diversity and clinical relevance of seal parvovirus (sepv) infections was evaluated in both harbor and grey seals (halichoerus grypus) that lived in northwestern european coastal waters from ...201425390639
evidence of land-sea transfer of the zoonotic pathogen campylobacter to a wildlife marine sentinel species.environmental pollution often accompanies the expansion and urbanization of human populations where sewage and wastewaters commonly have an impact on the marine environments. here, we explored the potential for faecal bacterial pathogens, of anthropic origin, to spread to marine wildlife in coastal areas. the common zoonotic bacterium campylobacter was isolated from grey seals (halichoerus grypus), an important sentinel species for environmental pollution, and compared to isolates from wild bird ...201525401947
grey seals use anthropogenic signals from acoustic tags to locate fish: evidence from a simulated foraging task.anthropogenic noise can have negative effects on animal behaviour and physiology. however, noise is often introduced systematically and potentially provides information for navigation or prey detection. here, we show that grey seals (halichoerus grypus) learn to use sounds from acoustic fish tags as an indicator of food location. in 20 randomized trials each, 10 grey seals individually explored 20 foraging boxes, with one box containing a tagged fish, one containing an untagged fish and all othe ...201525411449
by-catch of grey seals (halichoerus grypus) in baltic fisheries--a bayesian analysis of interview survey.baltic seals are recovering after a population decline. the increasing seal stocks cause notable damage to fisheries in the baltic sea, with an unknown number of seals drowning in fishing gear every year. thus, sustainable seal management requires updated knowledge of the by-catch of seals--the number of specimens that die in fishing gear. we analyse the by-catch of grey seals (halichoerus grypus) in finland, sweden, and estonia in 2012. we collect data with interviews (35 in finland, 54 in swed ...201425423168
exposing the grey seal as a major predator of harbour porpoises.harbour porpoises (phocoena phocoena) stranding in large numbers around the southern north sea with fatal, sharp-edged mutilations have spurred controversy among scientists, the fishing industry and conservationists, whose views about the likely cause differ. the recent detection of grey seal (halichoerus grypus) dna in bite marks on three mutilated harbour porpoises, as well as direct observations of grey seal attacks on porpoises, have identified this seal species as a probable cause. bite mar ...201525429021
bite injuries of grey seals (halichoerus grypus) on harbour porpoises (phocoena phocoena).bite-like skin lesions on harbour porpoises (phocoena phocoena) have been suspected to be caused by grey seals (halichoerus grypus), and a few field observations have been reported. bite-like skin lesions observed on stranded animals were characterized by two main components: large flaps of loose or missing skin and blubber with frayed edges and puncture lesions. definitive demonstration of predation by a grey seal was not reported so far in those stranded animals. in this study, five stranded p ...201425461599
identification of dna sequences that imply a novel gammaherpesvirus in seals.various herpesviruses have been discovered in marine mammals and are associated with a wide spectrum of disease. in the present study we describe the detection and phylogenetic analysis of a novel gammaherpesvirus, tentatively called phocine herpesvirus 7 (phhv-7), which was detected in samples collected during an outbreak of ulcerative gingivitis and glossitis from juvenile harbour seals (phoca vitulina) at the seal rehabilitation and research centre, the netherlands. the presence of this novel ...201525524165
phocine distemper virus: current knowledge and future directions.phocine distemper virus (pdv) was first recognized in 1988 following a massive epidemic in harbor and grey seals in north-western europe. since then, the epidemiology of infection in north atlantic and arctic pinnipeds has been investigated. in the western north atlantic endemic infection in harp and grey seals predates the european epidemic, with relatively small, localized mortality events occurring primarily in harbor seals. by contrast, pdv seems not to have become established in european ha ...201425533658
development of a one-step duplex rt-qpcr for the quantification of phocine distemper virus.worldwide, stranded marine mammals and the network personnel who respond to marine mammal mortality have provided much of the information regarding marine morbillivirus infections. an assay to determine the amount of virus present in tissue samples would be useful to assist in routine surveying of animal health and for monitoring large-scale die-off events. false negatives from poor-quality samples prevent determination of the true extent of infection, while only small amounts of tissue samples ...201525647591
isolation and phylogenetic characterization of streptococcus halichoeri from a european badger (meles meles) with pyogranulomatous pleuropneumonia.clinical and pathological studies in european badgers (meles meles) are limited. badgers play a significant role in the epidemiology of bovine tuberculosis (tb) in some countries and an accurate diagnosis is needed for this infection. however, the lesions of bovine tb are similar to those associated with other pathogens, making pathological diagnosis difficult. in the present study, streptococcus halichoeri was isolated from a european badger with pyogranulomatous pleuropneumonia and suspected o ...201525678424
[infestation rates of the main commercial fish species with larvae of contracaecum osculatum (rudolphi, 1802) (nematoda: anisakidae) in russian waters of the south baltic in 2000-2012].the infestation dynamic of the sprat (sprattus sprattus balticus), the baltic herring (clupea harengus membras), and the baltic cod (gadus morhua callaris) with nematodes contracaecum osculatum 1 (anisakidae) from russian waters of the south baltic were studied in 2000-2012. peculiarities of larval growth in different hosts were analyzed. a total of 6233 fish specimens were investigated, including 1420, 3867, and 946 specimens of sprat, herring, and cod, respectively. the prevalence and mean int ...201525693327
analysis of streptococcus agalactiae pan-genome for prevalence, diversity and functionality of integrative and conjugative or mobilizable elements integrated in the trna(lys ctt) gene.streptococcus agalactiae is the first cause of invasive infections in human neonates and is also a major bovine and fish pathogen. high genomic diversity was observed in this species that hosts numerous mobile genetic elements, in particular elements transferable by conjugation. this works aims to evaluate the contribution of these elements to gbs genome diversity. focusing on genomic islands integrated in the trna(lys) (ctt) gene, a known hotspot of recombination, an extensive in silico search ...201525832353
distance measures and optimization spaces in quantitative fatty acid signature analysis.quantitative fatty acid signature analysis has become an important method of diet estimation in ecology, especially marine ecology. controlled feeding trials to validate the method and estimate the calibration coefficients necessary to account for differential metabolism of individual fatty acids have been conducted with several species from diverse taxa. however, research into potential refinements of the estimation method has been limited. we compared the performance of the original method of ...201525859330
adiponectin and insulin in gray seals during suckling and fasting: relationship with nutritional state and body mass during nursing in mothers and pups.animals that fast during breeding and/or development, such as phocids, must regulate energy balance carefully to maximize reproductive fitness and survival probability. adiponectin, produced by adipose tissue, contributes to metabolic regulation by modulating sensitivity to insulin, increasing fatty acid oxidation by liver and muscle, and promoting adipogenesis and lipid storage in fat tissue. we tested the hypotheses that (1) circulating adiponectin, insulin, or relative adiponectin gene expres ...201525860828
offspring size at weaning affects survival to recruitment and reproductive performance of primiparous gray seals.offspring size affects survival and subsequent reproduction in many organisms. however, studies of offspring size in large mammals are often limited to effects on juveniles because of the difficulty of following individuals to maturity. we used data from a long-term study of individually marked gray seals (halichoerus grypus; fabricius, 1791) to test the hypothesis that larger offspring have higher survival to recruitment and are larger and more successful primiparous mothers than smaller offspr ...201525897381
spatial distribution of fishes in a northwest atlantic ecosystem in relation to risk of predation by a marine mammal.1. numerous studies have shown that, at spatial scales of metres to several kilometres, animals balance the trade-off between foraging success and predation mortality by increasing their use of safer but less profitable habitats as predation risk increases. however, it is less clear whether prey respond similarly at the larger spatiotemporal scales of many ecosystems. 2. we determine whether this behaviour is evident in a large marine ecosystem, the southern gulf of st. lawrence (sgsl, 75 000 km ...201525976520
a novel tool to mitigate by-catch mortality of baltic seals in coastal fyke net fishery.developing methods to reduce the incidental catch of non-target species is important, as by-catch mortality poses threats especially to large aquatic predators. we examined the effectiveness of a novel device, a "seal sock", in mitigating the by-catch mortality of seals in coastal fyke net fisheries in the baltic sea. the seal sock developed and tested in this study was a cylindrical net attached to the fyke net, allowing the seals access to the surface to breathe while trapped inside fishing ge ...201525993534
trends in stranding and by-catch rates of gray and harbor seals along the northeastern coast of the united states: evidence of divergence in the abundance of two sympatric phocid species?harbor seals and gray seals are sympatric phocid pinnipeds found in coastal waters of the temperate and sub-arctic north atlantic. in the northwest atlantic, both species were depleted through a combination of subsistence hunts and government supported bounties, and are now re-occupying substantial portions of their original ranges. while both species appear to have recovered during the past 2 decades, our understanding of their population dynamics in us waters is incomplete. here we describe tr ...201526200461
a novel approach to quantifying the spatiotemporal behavior of instrumented grey seals used to sample the environment.paired with satellite location telemetry, animal-borne instruments can collect spatiotemporal data describing the animal's movement and environment at a scale relevant to its behavior. ecologists have developed methods for identifying the area(s) used by an animal (e.g., home range) and those used most intensely (utilization distribution) based on location data. however, few have extended these models beyond their traditional roles as descriptive 2d summaries of point data. here we demonstrate h ...201526213626
chlorinated herbicides in fish, birds and mammals in the baltic sea.the aim of the present work was to determine the concentration levels, as well as accumulation and magnification coefficients, of triazine derivatives in herring gulls and baltic grey seals 11 years after a ban on their use in the eu and eight after their exclusion in poland. dead birds were collected in the coastal zone of the gulf of gdansk in the years 2010-2012. the grey seals, on the other hand, were from before 2007, when s-triazine derivatives were still in use. triazine herbicides (atraz ...201726246644
conspecific recognition and aggression reduction to familiars in newly weaned, socially plastic mammals.recognising conspecifics and behaving appropriately towards them is a crucial ability for many species. grey seals (halichoerus grypus) show varying capabilities in this regard: mother-pup recognition has been demonstrated in some geographical populations but is absent in others, yet there is evidence that individuals aggregate with prior associates. the recognition capabilities of newly weaned grey seal pups were investigated using class recognition trials within the habituation/dishabituation ...201726246656
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