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1.
Aerial surveys of ice-associated pinnipeds were conducted south of St. Lawrence Island in March 2001. The observed distributions of bearded seals (Erignathus barbatus), ribbon seals (Phoca fasciata), ringed seals (P. hispida), spotted seals (P. largha), and walruses (Odobenus rosmarus) were compared to the distributions of ice habitat types and benthic communities. Randomization tests were used to investigate habitat selection for each species. Both ringed seals and walruses preferred large ice floes (>48 m in diameter) that were common in the interior ice pack. Spotted seals favored smaller ice floes (<20 m in diameter) common near the ice edge, and bearded seals avoided large floes and preferred transitional habitat between small and large floes. Ringed seals also seemed to prefer areas with greater than 90% sea ice coverage, and bearded seals preferred 70–90% sea ice coverage while avoiding areas with greater than 90% coverage. All species, except spotted seals, were seen most frequently in a region of high benthic biomass, and randomization tests suggested that bearded seals actively selected that region. 相似文献
2.
Feeding ecology of phocid seals and some walrus in the Alaskan and Canadian Arctic as determined by stomach contents and stable isotope analysis 总被引:1,自引:0,他引:1
Larissa-A. Dehn Gay G. Sheffield Erich H. Follmann Lawrence K. Duffy Dana L. Thomas Todd M. O’Hara 《Polar Biology》2007,30(2):167-181
Feeding habits of ringed (Phoca hispida), bearded (Erignathus barbatus), spotted (Phoca largha) and ribbon (Phoca fasciata) seals and walrus (Odobenus rosmarus) were studied using stomach contents and stable carbon and nitrogen isotopes. Bearded seals fed benthically, primarily crustaceans and mollusks. Both zooplankton and fish were significant prey for ringed seals, while fish was principal spotted seal prey. Few gastric contents were available from ribbon seals. δ15N was positively correlated with age in ribbon seals and δ13C was positively correlated with age in ringed and ribbon seals. δ15N was highest in spotted seals, in agreement with their fish-dominated diet. δ15N was not different between Alaskan-harvested ringed and bearded seals, while δ15N was lowest in ribbon seals and walrus. Carbon-13 was most enriched in bearded seals and walrus reflecting benthic ecosystem use. Canadian ringed seals were depleted in 13C compared to Alaskan pinnipeds, likely because of Beaufort Sea versus Chukchi and Bering seas influence. 相似文献
3.
Movements and behavior of satellite-tagged spotted seals (Phoca largha) in the Bering and Chukchi Seas 总被引:1,自引:0,他引:1
Lloyd F. Lowry Kathryn J. Frost Randall Davis Douglas P. DeMaster Robert S. Suydam 《Polar Biology》1998,19(4):221-230
Satellite-linked tags were attached to 12 spotted seals (Phoca largha) captured at a coastal lagoon in the eastern Chukchi Sea during August 1991–1993. Movements of seals were tracked for 32–298
days using the Argos system. Of 9,651 total location records obtained, 7,268 were usable. Individual seals were located on
41–96% of the days that tags were operational. During August–November, tagged seals alternated haul-outs at coastal sites
lasting 1–304 h with trips to sea of 14–901 h. Coastal haul-outs occurred at 14 sites in western Alaska and eastern Russia.
On several trips to sea, seals covered distances of more than 1,000 km. Movement southward from the Chukchi Sea generally
began in October, with most of the seals passing through the Bering Strait during November. Seals first hauled out on sea
ice in October (Chukchi Sea) or November (Bering Sea), and generally moved southward during October–December as sea-ice coverage
increased. Seven seals, whose transmitters were still operating, spent December to June in the Bering Sea region between Kuskokwim
Bay and Anadyr Gulf, which corresponded to the location of the ice front. The seals made active east-west movements within
the ice front. Spotted seals are unlike other ice-breeding seals in that they regularly use coastal haul-outs during summer
and autumn. Compared to the closely related Pacific harbor seal (Phoca vitulina richardsi), spotted seals make much longer trips to sea and spend longer continuous periods at their haul-outs during summer and autumn.
Received: 9 April 1997 / Accepted: 30 September 1997 相似文献
4.
Distribution and diving behaviour of crabeater seals (Lobodon carcinophagus) off Queen Maud Land 总被引:4,自引:4,他引:0
Eight crabeater seals (Lobodon carcinophagus) (three females, five males), ranging in body mass between 125 and 220 kg, were captured off Queen Maud Land (70–72°S, 7–16°W) during the last week of February, just after moulting, and tagged with Argos satellite-linked dive recorders to provide data on location and diving depth and duration. During the first few weeks of March the seals were moving in the pack ice along the continental shelf edge, close to the coast of Queen Maud Land. In April and May, when the pack ice extended northwards, most of the seals moved north, one reaching 63°S in late May. In the first half of June the two remaining seals turned south and moved back deep into the pack ice. The seals made about 150 dives per day each throughout the study period. Ninety percent of these were made to depths of less than 52 m. Individual maximum diving depths varied between 288 and 528 m. In March the seals were most active at night, when the dive depth was shallower than during the day. In April and May the seals were more active during day-time, with an absence of any diurnal change in divng depth. These results support the notion that crabeater seals predominantly feed on krill in Antarctic pack ice, even when winter returns to the waters off Queen Maud Land.Publication no. 134 of the Norwegian Antarctic Research Expedtion 1992/1993 相似文献
5.
Seven post-moulting adult ringed seals (Phoca hispida) were equipped with Satellite Linked Dive Recorders in Svalbard in July 1996 to determine if ringed seals conduct long-distance
post-moulting feeding excursions, and to obtain details of their diving behaviour. The mean duration of tags was 206 days
(range 103–325). Two seals swam 400 km north to the drifting pack ice (82°N). The rest undertook more local movements. Forty-eight
percent of all dives were shallower than 20 m and 90% were shallower than 100 m. Ninety-five percent of all dive durations
were shorter than 10 min, and 99.5% were shorter than 15 min. This study has shown that adult ringed seals undertake varying
patterns of post-moulting excursions.
Accepted: 1 April 2000 相似文献
6.
Recent unidirectional climatic trends and changes in top predator population ecology suggest that long-term modifications may be happening in Hudson Bay, Canada. Effects of such changes on ice-obligated seal populations are expected but long-term studies are required to differentiate climate-induced changes from natural variation. We conducted strip-transect surveys in late spring in 1995–1997, 1999–2000 and 2007–2008 to estimate distribution, density and abundance of ice-obligated ringed (Phoca hispida) and bearded (Erignathus barbatus) seals in western Hudson Bay. When hauled out, ringed seals preferred land-fast and consolidated pack ice, whereas bearded seals preferred unconsolidated pack ice. Bearded and ringed seal density estimates varied from 0.0036 to 0.0229 seals/km2 of ice and from 0.46 to 1.60 seals/km2 of ice, respectively. Strong inter-annual variations were recorded in the abundance estimates of both species, with the largest abundance estimates in 1995 (104,162 and 1,494 ringed and bearded seals, respectively) and the lowest in 2008 for ringed seals (33,701) and 1997 for bearded seals (278). A sine function best described seal density estimates in western Hudson Bay and suggested a decadal cycle. Previous studies that reported low ringed seal demographic parameters in the 1990s and a recovery in the 2000s supported our interpretation of the survey results. We discuss our results in the context of climate warming and suggest that a long-term decline in ice-obligated seal density estimates may overlay a possible natural decadal cycle. 相似文献
7.
Margaret H. Cooper Suzanne M. Budge Alan M. Springer Gay Sheffield 《Polar Biology》2009,32(8):1137-1145
Four species of pagophilic phocid seals in the Western Arctic—bearded (Erignathus barbatus), ringed (Phoca hispida), ribbon (Phoca fasciata), and spotted (Phoca largha)—are particularly vulnerable to arctic warming trends. Documenting diet composition over time is one way in which the flexibility
of a species, in the face of broad ecosystem changes, can be measured. Because the fatty acid (FA) composition of depot lipids
has long been known to reflect diet, we analysed the FA composition of blubber samples collected from bearded (n = 30), ringed (n = 15), ribbon (n = 32) and spotted seals (n = 24). All animals were taken near Little Diomede Island in May and June 2003, providing a unique opportunity to study interspecies
differences with minimal effects of spatial and temporal variation. Bearded seal FA composition was significantly different
from all other seals (P < 0.001 in all cases), ringed seal FA composition was significantly different from that of both ribbon and spotted seals
(P < 0.001), but ribbon and spotted seal FA compositions could not be distinguished from each other. Overall, the blubber FA
compositions of ribbon, ringed and spotted seals implied diets dominated by pelagic prey. Inferences we made about current
diets of bearded and ringed seals suggest that certain prey important to them in this area in the 1970s remain important today,
despite notable changes in the ecosystem. We believe that blubber FA analysis will be a useful tool in assessing the response
of ice-associated pinnipeds and their ecosystem to changes associated with arctic warming. 相似文献
8.
Brendan P. Kelly Oriana H. Badajos Mervi Kunnasranta John R. Moran Micaela Martinez-Bakker Douglas Wartzok Peter Boveng 《Polar Biology》2010,33(8):1095-1109
Population structure and patterns of habitat use among ringed seals (Phoca hispida) are poorly known, in part because seasonal movements have not been adequately documented. We monitored the movements of
98 ringed seals in the Beaufort and Chukchi seas between 1990 and 2006 using three forms of telemetry. In the winter—spring
period (when the seals were occupying shorefast ice), we used radio and ultra-sonic tags to track movements above and below
the ice, respectively. We used satellite-linked transmitters in summer and fall (when the seals ranged away from their winter
sites) to track at-sea movements. In the shorefast ice habitat, the home ranges of 27 adult males ranged from <1 to 13.9 km2 (median = 0.628) while the home ranges of 28 adult females ranged from <1 to 27.9 km2 (median = 0.652). The 3-dimensional volumes used by 9 seals tracked acoustically under the ice averaged 0.07 (SD = 0.04) km3 for subadults and adult males and 0.13 (SD = 0.04) km3 for adult females. Three of the radio-tracked seals and 9 tracked by satellite ranged up to 1,800 km from their winter/spring
home ranges in summer but returned to the same small (1–2 km2) sites during the ice-bound months in the following year. The restricted movements of ringed seals during the ice-bound season—including
the breeding season—limits their foraging activities for most of the year and may minimize gene flow within the species. 相似文献
9.
Alicia M. Hendrix Kathi A. Lefebvre Lori Quakenbush Anna Bryan Raphaela Stimmelmayr Gay Sheffield Gabriel Wisswaesser Maryjean L. Willis Emily K. Bowers Preston Kendrick Elizabeth Frame Thomas Burbacher David J. Marcinek 《Marine Mammal Science》2021,37(4):1292-1308
Domoic acid (DA) and saxitoxin (STX)-producing algae are present in Alaskan seas, presenting exposure risks to marine mammals that may be increasing due to climate change. To investigate potential increases in exposure risks to four pagophilic ice seal species (Erignathus barbatus, bearded seals; Pusa hispida, ringed seals; Phoca largha, spotted seals; and Histriophoca fasciata, ribbon seals), this study analyzed samples from 998 seals harvested for subsistence purposes in western and northern Alaska during 2005–2019 for DA and STX. Both toxins were detected in bearded, ringed, and spotted seals, though no clinical signs of acute neurotoxicity were reported in harvested seals. Bearded seals had the highest prevalence of each toxin, followed by ringed seals. Bearded seal stomach content samples from the Bering Sea showed a significant increase in DA prevalence with time (logistic regression, p = .004). These findings are consistent with predicted northward expansion of DA-producing algae. A comparison of paired samples taken from the stomachs and colons of 15 seals found that colon content consistently had higher concentrations of both toxins. Collectively, these results suggest that ice seals, particularly bearded seals (benthic foraging specialists), are suitable sentinels for monitoring HAB prevalence in the Pacific Arctic and subarctic. 相似文献
10.
Quantitative assessment of species identification in aerial transect surveys for ice‐associated seals 下载免费PDF全文
Brett T. McClintock Erin E. Moreland Joshua M. London Shawn P. Dahle Gavin M. Brady Erin L. Richmond Kymberly M. Yano Peter L. Boveng 《Marine Mammal Science》2015,31(3):1057-1076
Technological advances have facilitated collection of vast quantities of photographic data from aerial surveys of marine mammals. However, when it is difficult to distinguish species from a distance, reliable identification from aerial images can often be challenging. This is the case for ice‐associated seals, species for which global climate change has motivated intensive monitoring efforts in recent years. We assess species and age class identification from aerial images of four ice seal species (bearded seals, Erignathus barbatus; ribbon seals, Histriophoca fasciata; ringed seals, Pusa hispida; spotted seals, Phoca largha) in the Bering Sea. We also investigate the specific phenomenological and behavioral traits commonly associated with species identification and observer confidence. We generally found species and age class misidentification occurred at relatively low levels, but only 83% of spotted seals tended to be correctly identified (with 11% mistaken as ribbon seals). We also found certain traits were strong predictors for observed species, age class, or observer confidence. Our findings add to the growing body of evidence that species misidentification is pervasive in passive sampling of animal populations. Even low levels of misidentification have been demonstrated to induce substantial biases in estimators of species distribution and abundance, and it is important that statistical models account for such errors. 相似文献
11.
John L. Bengtson Lisa M. Hiruki-Raring Michael A. Simpkins Peter L. Boveng 《Polar Biology》2005,28(11):833-845
Aerial surveys were conducted in 1999 and 2000 to estimate the densities of ringed (Phoca hispida) and bearded (Erignathus barbatus) seals in the eastern Chukchi Sea. Survey lines were focused mainly on the coastal zone within 37 km of the shoreline, with
additional lines flown 148–185 km offshore to assess how densities of seals changed as a function of distance from shore.
Satellite-linked time-depth recorders were attached to ringed seals in both years to evaluate the time spent basking on the
ice surface. Haulout patterns indicated that ringed seals transitioned to basking behavior in late May and early June, and
that the largest proportion of seals (60–68%) was hauled out between 0830 and 1530 local solar time. Ringed seals were relatively
common in nearshore fast ice and pack ice, with lower densities in offshore pack ice. The average density of ringed seals
was 1.91 seals km−2 in 1999 (range 0.37–16.32) and 1.62 seals km−2 in 2000 (range 0.42–19.4), with the highest densities of ringed seals found in coastal waters south of Kivalina and near
Kotzebue Sound. The estimated abundance of ringed seals for the entire study area was similar in 1999 (252,488 seals, SE=47,204)
and 2000 (208,857 seals, SE=25,502). Bearded seals were generally more common in offshore pack ice, with the exception of
high bearded seal numbers observed near the shore south of Kivalina. Bearded seal densities were not adjusted for haulout
behavior, and therefore, abundance was not estimated. Unadjusted average bearded seal density was 0.07 seals km−2 in 1999 (range 0.011–0.393) and 0.14 seals km−2 in 2000 (range 0.009–0.652). Levels of primary productivity, benthic biomass, and fast ice distribution may influence the
distributions of ringed and bearded seals in the Chukchi Sea. Information on movement and haulout behavior of ringed and bearded
seals would be very useful for designing future surveys. 相似文献
12.
The feeding habits of harp seals (Phoca groenlandica) in the Barents Sea were examined in studies conducted during June 1991, September 1990 and 1991, and October 1992. Analyses of stomach and intestinal contents were carried out and concurrent estimates of prey abundance were made using trawl gear. Harp seals appeared to feed at low intensity in the pack ice belt during the first half of June. There was little potential prey in the water column, but prawns (Pandalus borealis), capelin (Mallotus villosus) and polar cod (Boreogadus saida) were abundant close to the bottom. In September, the seals sampled in the northern pack ice areas of the Barents Sea fed on the pelagic amphipod Parathemisto libellula, krill (Thysanoessa spp.), prawns and, to a lesser extent, on fish species such as polar cod, sculpins (Cottidae) and snailfish (Liparidae). Trawling revealed that large quantities of Parathemisto libellala were present in the upper layers of the water column. Fish, mainly capelin and polar cod, were less abundant and occurred in deeper waters. In mid-October, the diet of seals in the northern Barents Sea consisted mainly of amphipods (Parathemisto sp.). Later in October, when increasing pack ice cover forced the harp seals to move south, the diet seemed to change from amphipods to fish prey, predominantly capelin and polar cod. 相似文献
13.
Yann Planque Jrme Spitz Matthieu Authier Gaël Guillou Ccile Vincent Florence Caurant 《Ecology and evolution》2021,11(15):10004
Sympatric harbour (Phoca vitulina) and grey seals (Halichoerus grypus) are increasingly considered potential competitors, especially since recent local declines in harbour seal numbers while grey seal numbers remained stable or increased at their European core distributions. A better understanding of the interactions between these species is critical for conservation efforts. This study aimed to identify the trophic niche overlap between harbour and grey seals at the southern limit of their European range, in the Baie de Somme (BDS, Eastern English Channel, France), where numbers of resident harbour seals and visiting grey seals are increasing exponentially. Dietary overlap was identified from scat contents using hierarchical clustering. Isotopic niche overlap was quantified using δ13C and δ15N isotopic values from whiskers of 18 individuals, by estimating isotopic standard ellipses with a novel hierarchical model developed in a Bayesian framework to consider both intraindividual variability and interindividual variability. Foraging areas of these individuals were identified from telemetry data. The three independent approaches provided converging results, revealing a high trophic niche overlap due to consumption of benthic flatfish. Two diet clusters were dominated by either small or large benthic flatfish; these comprised 85.5% [CI95%: 80.3%–90.2%] of harbour seal scats and 46.8% [35.1%–58.4%] of grey seal scats. The narrower isotopic niche of harbour seals was nested within that of grey seals (58.2% [22.7%–100%] overlap). Grey seals with isotopic values similar to harbour seals foraged in coastal waters close to the BDS alike harbour seals did, suggesting the niche overlap may be due to individual grey seal strategies. Our findings therefore provide the basis for potential competition between both species (foraging on benthic flatfish close to the BDS). We suggest that a continued increase in seal numbers and/or a decrease in flatfish supply in this area could cause/amplify competitive interactions and have deleterious effects on harbour seal colonies. 相似文献
14.
Peter J. H. Reijnders Sophie M. J. M. Brasseur Erik H. W. G. Meesters 《Biology letters》2010,6(6):854-857
The annual reproductive cycle of most seal species is characterized by a tight synchrony of births. Typically, timing of birth shows little inter-annual variation. Here, however we show that harbour seals Phoca vitulina from the Wadden Sea (southeast North Sea) have shortened their yearly cycle, moving parturition to earlier dates since the early 1970s. Between 1974 and 2009, the birth date of harbour seals shifted on average by −0.71 d yr−1, three and a half weeks (25 days) earlier, in the Dutch part of the Wadden Sea. Pup counts available for other parts of the Wadden Sea were analysed, showing a similar shift. To elucidate potential mechanism(s) for this shift in pupping phenology, possible changes in population demography, changes in maternal life-history traits and variations in environmental conditions were examined. It was deduced that the most likely mechanism was a shortening of embryonic diapause. We hypothesize that this could have been facilitated by an improved forage base, e.g. increase of small fishes, attributable to overfishing of large predator fishes and size-selective fisheries. 相似文献
15.
To examine seasonal and inter-annual shifts in the energy requirements of captive harp seals (Phoca groenlandica), metabolic rate and body temperature were repeatedly measured over the annual cycle. Seasonal shifts were evident in both
parameters, with spring and summer (April to September) peaks decreasing throughout fall and winter (October to March). Seasonal
changes in oxygen consumption concur with earlier published reports and data presented here validate these trends inter-annually.
The standard metabolic rates (SMRs) of all seals were lower than predicted during fall/winter, but were indistinguishable
from expected rates during spring/summer. Although individual variation in metabolic rate was largely independent of changes
in both total body mass and predicted total body fat over the year, such variation was more closely related to changes in
predicted lean body mass. Both deep rectal and core body temperatures co-varied with metabolic rate, perhaps indicating a
metabolic defense of fat for thermoregulation. The implications of these shifting basal requirements are considered in the
light of calculating the impact of the harp seal herd on fisheries resources in the Northwest Atlantic.
Received: 18 December 1996 / Accepted: 30 April 1997 相似文献
16.
Age is an important factor that significantly impacts the gut microbiota of various mammals. Captive spotted seals (Phoca largha) provide an ideal opportunity to study how age affects their gut microbiota, excluding other environmental factors, which is a challenge when monitoring wildlife. Here, the bacterial composition of the feces of captive spotted seals from four age groups were analyzed; namely, pup (<1 year old), juvenile (1–2 years old), subadult (2–3 years old), and adult (≥4 years old). Firmicutes were the dominant bacteria in all measured feces; however, the composition of gut microbiota in seals of different ages was distinct. Blautia, Slackia, and an unclassified Peptostreptococcaceae were more abundant in pups; Clostridium was abundant in juveniles; Fusobacterium, Bacteroides, and Psychrobacter were abundant in subadults; and Dorea and Peptostreptococcus abundant in adults. Two and 4 years of age appeared to be the most influential time nodes for variation in gut microbiota. In conclusion, this study identified age-related differences in the composition of gut microbiota in P. largha. 相似文献
17.
Among the most numerous seabird and pinniped species of the Fram Strait and the Greenland Sea, little auks Alle alle and harp seals Pagophila (Phoca) groenlandica are very abundant in the mixed Polar/Arctic Waters at the front between the two water masses. This must reflect the presence
of very high concentrations of their food, Arctic zooplankton and nekton, massively attracting their predators. Such a high
biological production seems to be depending on new primary production based on upwelling and high nutrient concentration.
This usually takes place at the ice edge (e.g. July 2005), but hydrological conditions such as eddies can modify its position,
east of the front in open water as caused by a subsurface eddy (August 2005), or in ice-covered areas if westerly winds push
the pack ice to the east, eventually covering an eddy and causing very high concentrations of little auks and harp seals (July
2008). On the other hand, a dramatic decrease of pack ice coverage can move this water mass farther north and west, making
it inaccessible to little auks during their breeding season, and apparently causing breeding failure in Jan Mayen in July
2005. In future years, if a much stronger diminution in sea ice coverage will take place, similar to the retreat in 2005 and
2007, the failure might affect the whole Spitsbergen population, as well as other seabird species feeding mainly at the ice
edge. 相似文献
18.
Two adult female leopard seals (Hydrurga leptonyx) were tagged with satellite-linked dive recorders off Queen Maud Land, Antarctica, just after moulting in mid-February. The
transmitters transmitted for 80 and 220 days, respectively. Both seals remained within the pack ice relatively close to the
Antarctic Continent until early May, when contact was lost with one seal. The one remaining seal then migrated north, to the
east side of the South Sandwich Islands in 3 weeks, whereafter it headed east, until contact was lost at 55°S in early September.
From mid-May to late September this animal always stayed close to the edge of the pack ice. Both seals made mostly short (<5 min)
dives to depths of 10–50 m and only occasionally dove deeper than 200 m, the deepest dive recorded being 304 m. A nocturnal
diving pattern was evident in autumn and early winter, while day-time diving prevailed in mid-winter. Haul out probability
was highest at mid-day (about 40% in late February and more than 80% in March and April). From May till September the remaining
animal mainly stayed at sea, in the vicinity of the pack ice, with only occasional haul outs. These data suggest that a portion
of the adult leopard seals may spend the winter mainly in open water, off the edge of the pack ice, where they primarily hunt
near the surface. In that case, it is likely that krill (Euphausia superba), as well as penguins, young crabeater seals (Lobodon carcinophaga) and a variety of fish are important prey items. 相似文献
19.
Serologic evidence of Brucella infection in pinnipeds along the coast of Hokkaido,the northernmost main island of Japan 下载免费PDF全文
Erika Abe Kazue Ohishi Tsuyoshi Ishinazaka Kei Fujii Tadashi Maruyama 《Microbiology and immunology》2017,61(3-4):114-122
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 ELISA 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 and from 66% (n = 41) of spotted seals (P. largha), 15% (n = 20) of ribbon seals (Histriophoca fasciata) and 18% (n = 17) of Western Steller's sea lions (Eumetopias jubatus jubatus) in the Shiretoko Peninsula. Anti‐Brucella antibodies were detected at higher absorbance in 1‐ to 4‐year‐old harbor seals than in the pups and mature animals, suggesting either that Brucella infection mainly occurs after weaning or that it is maternally transmitted to pups with premature or suppressed immunity. Anti‐Brucella antibodies were detected in both immature and mature spotted seals and ribbon seals, with higher absorbance in the former. The antibodies were detected only in mature Western Steller's sea lions. Western blot analysis of the serum samples showed some differences in band appearances, namely discrete versus smeary, and in the number of bands, indicating that multiple different Brucella may be prevalent in pinnipeds in Hokkaido. Alternatively, the Brucella of pinnipeds may have some intra‐species diversity. 相似文献
20.
The distribution, movements and diving of high-arctic harbour seals (Phoca vitulina) were studied in Svalbard, Norway, from 1992 to 1995. A total of 14 seals were equipped with satellite transmitters at Prins
Karls Forland (ca. 78°30′N 12°E). These gave data on position, but ten also gave information on dive depths (N ∼ 160,000) and dive durations (N ∼ 162,000). Dive-depth frequencies show that ∼50% of the diving is shallower than 40 m, and that 95% of the diving is shallower
than 250 m. Based on dive-duration frequencies, ∼50% of the dives lasted 2–4 min, 90% of the dives lasted less than 7 min,
and 97% were shorter than 10 min. All but three seals stayed in the tagging area.
Accepted: 6 October 2000 相似文献