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  • 1
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    Online Resource
    Estimating the Blubber Content of Phocid Seals
    Canadian Science Publishing ; 1990
    In:  Canadian Journal of Fisheries and Aquatic Sciences Vol. 47, No. 6 ( 1990-06-01), p. 1223-1227
    Details
    In: Canadian Journal of Fisheries and Aquatic Sciences, Canadian Science Publishing, Vol. 47, No. 6 ( 1990-06-01), p. 1223-1227
    Abstract: We have investigated the relationships between percent blubber content and xiphostemal blubber thickness or girth-to-length ratios in ringed seal (Phoca hispida), harp seal (Phoca groeniandica), and grey seal (Halichoerus grypus). The blubber content was significantly correlated with blubber depths and girth-to-length ratios in all three species, in addition, we have developed an estimator for percent blubber content (the LMD-index) based on standard length (L, in meters), body mass (M, in kilograms), and on blubber thickness (d, in meters) measured at a defined position dorsally. From these variables the percent blubber content (B%) can be estimated by the expression B% = 4.44 + 5693 [Formula: see text], with a standard error of the estimate of three percentage units. This index also gave reasonable estimates for blubber content in three harbour seals (Phoca vitulina) and eight bearded seals (Erignatus harbatus).
    Type of Medium: Online Resource
    ISSN: 0706-652X , 1205-7533
    URL: Article
    DOI: 10.1139/f90-142
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 1990
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    detail.hit.zdb_id: 1473089-3
    SSG: 21,3
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  • 2
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    Diving activity in nursing bearded seal ( Erignathus barbatus ) pups
    Canadian Science Publishing ; 1994
    In:  Canadian Journal of Zoology Vol. 72, No. 1 ( 1994-01-01), p. 96-103
    Details
    In: Canadian Journal of Zoology, Canadian Science Publishing, Vol. 72, No. 1 ( 1994-01-01), p. 96-103
    Abstract: In this study we used time-depth recorders to quantify the diving activity of four nursing bearded seal (Erignathus barbatus) pups over a 10-day period. The pups were 4–7 days old at the start of the experiments. Their daily mass gain was 3.3 ± 0.4 kg (mean ± SD). A total of 530 h, which included 6248 dives, was recorded from the four pups. The pups spent an average of 53% of the recorded time in the water and 47% of the time hauled out. When the pups were in the water they were submerged 42% of the time, while 58% of the time was spent at the surface. Most dives were shallow and of short duration. Dive depth and duration were 10 ± 10 m and 62 ± 46 s and the maximum recorded values were 84 m and 5.5 min, respectively. The pups spent more time in the water and increased the number of long dives and the mean dive duration with age. The duration of haul-out intervals where nursing could take place was 1.93 ± 2.01 h, with a recorded maximum of 8.25 h. The time between these haul-out intervals was 2.18 ± 2.44 h, with a maximum of 9.73 h. A diurnal pattern in haul-out activity was documented; pups spent significantly more time hauled out from 07:00 to 10:00 and from 21:00 to 24:00 than during the rest of the day.
    Type of Medium: Online Resource
    ISSN: 0008-4301 , 1480-3283
    URL: Article
    DOI: 10.1139/z94-013
    RVK:
    WA 15000
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 1994
    detail.hit.zdb_id: 1490831-1
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  • 3
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    Online Resource
    Diving behaviour of lactating bearded seals (〈i〉Erignathus barbatus〈/i〉) in the Svalbard area
    Canadian Science Publishing ; 2000
    In:  Canadian Journal of Zoology Vol. 78, No. 8 ( 2000), p. 1408-1418
    Details
    In: Canadian Journal of Zoology, Canadian Science Publishing, Vol. 78, No. 8 ( 2000), p. 1408-1418
    Type of Medium: Online Resource
    ISSN: 1480-3283 , 0008-4301
    URL: Article
    DOI: 10.1139/cjz-78-8-1408
    RVK:
    WA 15000
    Language: Unknown
    Publisher: Canadian Science Publishing
    Publication Date: 2000
    detail.hit.zdb_id: 1490831-1
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  • 4
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    Diving in ringed seal ( Phoca hispida ) pups during the nursing period
    Canadian Science Publishing ; 1993
    In:  Canadian Journal of Zoology Vol. 71, No. 5 ( 1993-05-01), p. 991-996
    Details
    In: Canadian Journal of Zoology, Canadian Science Publishing, Vol. 71, No. 5 ( 1993-05-01), p. 991-996
    Abstract: In this study, activity and diving performance of nursing ringed seal (Phoca hispida) pups were quantified using time–depth recorders. A total of 1040 h of activity, including 7506 diving cycles, was collected from three female pups. The pups spent 50.3% of their time in the water and 49.7% hauled out on the ice. When the pups were in the water, 20.5% of the time was spent actively diving, while 79.5% of the recorded wet time was spent at the surface. Most of the dives were shallow and of short duration. Mean dive duration was 59.1 ± 63.5 s (SD). Maximum dive durations for the three pups were 5.8, 7.5, and 12 min. Maximum recorded depths were 12, 35, and 89 m. These depths represented the bottom in the area where each pup was situated. The average duration of haul-out sessions where nursing could take place was 6.3 ± 1.6 h, and the time between these sessions was 8.2 ± 3.2 h. The mean number of breathing holes found per pup was 8.7 ± 3.5. The large proportion of time spent in the water, the development of diving skills at an extremely young age, the use of multiple breathing holes, and the prolonged white-coat stage are all interpreted to be evolutionary responses to strong predation pressure, mainly from polar bears.
    Type of Medium: Online Resource
    ISSN: 0008-4301 , 1480-3283
    URL: Article
    DOI: 10.1139/z93-131
    RVK:
    WA 15000
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 1993
    detail.hit.zdb_id: 1490831-1
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  • 5
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    Oxygen stores and aerobic dive limit of ringed seals ( Phoca hispida )
    Canadian Science Publishing ; 1992
    In:  Canadian Journal of Zoology Vol. 70, No. 3 ( 1992-03-01), p. 458-461
    Details
    In: Canadian Journal of Zoology, Canadian Science Publishing, Vol. 70, No. 3 ( 1992-03-01), p. 458-461
    Abstract: In this paper we measured total lung capacity, myoglobin content of muscle tissue, and hemoglobin content of the blood of ringed seals (Phoca hispida). Based on this information and body composition analysis we estimated the total available oxygen stores of a diving average adult ringed seal (standard length 129 cm, body mass 73.7 kg) to be 4.5 L. The aerobic dive limit for a ringed seal of this size was estimated to be 8.9 min. Diving data from previous studies show that less than 4% of the dives of adult free-living ringed seals exceed this aerobic dive limit. Based on information from the literature on maximum breathhold capacity and observed maximum dive times of ringed and Weddell seals (Leptonychotes weddellii), the maximum breathhold capacity of adult ringed seals was suggested to be 26.1 min.
    Type of Medium: Online Resource
    ISSN: 0008-4301 , 1480-3283
    URL: Article
    DOI: 10.1139/z92-069
    RVK:
    WA 15000
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 1992
    detail.hit.zdb_id: 1490831-1
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  • 6
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    Reproductive effort of male hooded seals ( Cystophora cristata ): estimates from mass loss
    Canadian Science Publishing ; 1996
    In:  Canadian Journal of Zoology Vol. 74, No. 8 ( 1996-08-01), p. 1521-1530
    Details
    In: Canadian Journal of Zoology, Canadian Science Publishing, Vol. 74, No. 8 ( 1996-08-01), p. 1521-1530
    Abstract: This study investigated mass loss, body composition, and behaviour patterns of male hooded seals during the reproductive season. During the 6 years of study (between 1989 and 1995), 139 records of male mass were obtained that involved 115 individuals. Body masses of males ranged from 147 to 434 kg. Mean mass at first capture was 312.5 ± 53.0 kg (N = 119). Year, date of sampling, and age all significantly influenced mass. Nineteen males were recaptured at least twice during a single season. Mean rate of mass loss among these individuals was 2.5 ± 1.1 kg/day (range 0.7–4.6 kg/day). Body composition early in the breeding season, measured using tritiated water (N = 6), produced mean estimates of 51.6 ± 1.6% water, 29.3 ± 2.4% fat, 16.9 ± 0.7% protein, and 1.9 ± 0.2% ash. Time–depth recorders attached to three males indicated that they spent 84.7 ± 15.4% of their time hauled out on the surface of the ice during the breeding season. Each of these males was on the ice for a few days; they then spent a few hours at sea before returning to the ice surface. Mean dive depth was only 14.1 ± 3.2 m (maximum 66 m) and mean dive duration was only 1.7 ± 0.3 min (maximum 28 min). Extrapolating mean daily rates of body mass loss to encompass a 2.5-week breeding season, males would lose an average of 44 kg, which represents 14% of their mean body mass. Compared with values for males of other phocid species this value is conservative. It appears that the short breeding season among hooded seals is energetically advantageous for both sexes.
    Type of Medium: Online Resource
    ISSN: 0008-4301 , 1480-3283
    URL: Article
    DOI: 10.1139/z96-166
    RVK:
    WA 15000
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 1996
    detail.hit.zdb_id: 1490831-1
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  • 7
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    Population parameters of ringed seals ( Phoca hispida Schreber, 1775) in the Svalbard area
    Canadian Science Publishing ; 1987
    In:  Canadian Journal of Zoology Vol. 65, No. 4 ( 1987-04-01), p. 1021-1027
    Details
    In: Canadian Journal of Zoology, Canadian Science Publishing, Vol. 65, No. 4 ( 1987-04-01), p. 1021-1027
    Abstract: Samples were taken from 284 ringed seals (Phoca hispida) in the Svalbard area during April–July 1981 and March–April 1982. The age of 283 seals was determined by reading annuli in the cementum of the canine teeth. The mean age of the males was 11.3 years, and of the females, 14.9 years. Females were found to be significantly older than males. The mean length of sexually mature ringed seals was 128.9 cm for both sexes. The mean weight of adult males and females was 53.5 and 61.4 kg, respectively. Females were found to be significantly heavier than males. The sex ratio was 47.8% males and 52.2% females. Studies of microscopic sections of testis and epididymis from ringed seal males showed that 63, 75, and 80% of 5-, 6-, and 7-year-old animals, respectively, were sexually mature. The weights of testis and epididymis, diameters of tubuli, and the size of testis all showed a marked increase in the 5-year age-class. Macroscopic sections of ovaries from ringed seal females showed that 20, 60, and 80% of 3-, 4-, and 5-year-old animals, respectively, were sexually mature. The size of the ovaries showed a marked increase in the 5-year age-class. The ovulation rate of ringed seals from Svalbard was calculated to be 0.91.
    Type of Medium: Online Resource
    ISSN: 0008-4301 , 1480-3283
    URL: Article
    DOI: 10.1139/z87-162
    RVK:
    WA 15000
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 1987
    detail.hit.zdb_id: 1490831-1
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  • 8
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    Online Resource
    Monitoring ringed seal ( Phoca hispida ) activity by means of acoustic telemetry
    Canadian Science Publishing ; 1991
    In:  Canadian Journal of Zoology Vol. 69, No. 5 ( 1991-05-01), p. 1178-1182
    Details
    In: Canadian Journal of Zoology, Canadian Science Publishing, Vol. 69, No. 5 ( 1991-05-01), p. 1178-1182
    Abstract: This study was conducted in Kongsfjorden, Svalbard (78°55′N, 12°30′E), from May 6 to 13, 1989. An adult ringed seal (Phoca hispida) female was live captured and equipped with an acoustic depth–time transmitter to obtain information on diving and haul-out activities. A total of 153 h continuous activity, including 1321 diving cycles, was recorded. Of the total time, 38.2% was spent underwater, 16.6% breathing at the surface, and 45.2% hauling out on the ice. Excluding haul-out periods, the seal was submerged for 69.7% and at the surface for 30.3% of the total time spent in the water. Mean dive duration was 2.7 ± 2.7 (SD) min, and mean dive depth was 10.6 ± 9.0 m. Maximum recorded dive duration was 17 min, and maximum recorded dive depth was 40 m. Recorded activities showed a diurnal pattern, with most of the diving activities in the late afternoon and at night and most of the haul-out activity in the morning and during the day.
    Type of Medium: Online Resource
    ISSN: 0008-4301 , 1480-3283
    URL: Article
    DOI: 10.1139/z91-167
    RVK:
    WA 15000
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 1991
    detail.hit.zdb_id: 1490831-1
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  • 9
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    Online Resource
    Feeding Habits of Northeast Atlantic Harp Seals ( Phoca groenlandica ) along the Summer Ice Edge of the Barents Sea
    Canadian Science Publishing ; 1991
    In:  Canadian Journal of Fisheries and Aquatic Sciences Vol. 48, No. 11 ( 1991-11-01), p. 2180-2183
    Details
    In: Canadian Journal of Fisheries and Aquatic Sciences, Canadian Science Publishing, Vol. 48, No. 11 ( 1991-11-01), p. 2180-2183
    Abstract: Stomachs from 58 harp seals (Phoca groenlandica) from the northern part of the Barents Sea were collected between August 20 and September 5, 1987. Fifty-six of the stomachs contained identifiable remains. The amphipod Parathemisto libellula was the most common food item, found in 98% of the seal stomachs and constituting 57.9% of the total volume. Fish were the second most important prey group, with Arctic cod (Boreogadus saida) as the dominant species followed by Nybelin's sculpin (Triglops nybelini) and Greenland halibut (Reinhardtius hippoglossoides). Decapods, mainly Pandalus borealis, were also common as prey of harp seals. No sex- or age-related differences in choice of food were found. From knowledge of the depths at locations where seals were collected and the presence of fresh benthic fishes in the seal stomachs, it is assumed that harp seals could forage at depths below 300 m.
    Type of Medium: Online Resource
    ISSN: 0706-652X , 1205-7533
    URL: Article
    DOI: 10.1139/f91-257
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 1991
    detail.hit.zdb_id: 7966-2
    detail.hit.zdb_id: 1473089-3
    SSG: 21,3
    SSG: 12
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  • 10
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    Online Resource
    Autumn diet of harbour seals ( Phoca vitulina ) at Prins Karls Forland, Svalbard, assessed via scat and fatty-acid analyses
    Canadian Science Publishing ; 2004
    In:  Canadian Journal of Zoology Vol. 82, No. 8 ( 2004-08-01), p. 1230-1245
    Details
    In: Canadian Journal of Zoology, Canadian Science Publishing, Vol. 82, No. 8 ( 2004-08-01), p. 1230-1245
    Abstract: This study used hard-part analyses from scats (n = 117) and stomachs (n = 3) to investigate the diet of high Arctic harbour seals (Phoca vitulina L., 1758) living on Prins Karls Forland, Svalbard, in early autumn. Additionally, it compared the results of fatty-acid analyses of the seals' blubber versus that of potential prey with the findings of the more traditional diet assessment method. Svalbard harbour seals appear to be opportunistic, polyphagous feeders similar to the situation in other parts of their range. Members of the cod-family, and secondarily the sculpin-family, dominated the diet of harbour seals on Svalbard. Small fish comprised most of the diet of the harbour seals; invertebrates appeared to be insignificant. Atlantic cod (Gadus morhua L., 1758) was the most important species in the diet in terms of biomass, whereas polar cod (Boreogadus saida (Lepechin, 1774)) was the most frequently consumed prey. Our comparison between hard-part diet analyses and fatty acids is far from definitive, but it indicates a general influence of the diet on the fatty-acid composition of the inner blubber layer. However, it also suggests systematic selective processes in the incorporation of fatty acids into the blubber. Observed differences between the fatty-acid composition of the different blubber layers and possible differences between sex and age classes warrant further investigation.
    Type of Medium: Online Resource
    ISSN: 0008-4301 , 1480-3283
    URL: Article
    DOI: 10.1139/z04-093
    RVK:
    WA 15000
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 2004
    detail.hit.zdb_id: 1490831-1
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