Winter Distribution of Bearded Seals (Erignathus barbatus) in the Penny Strait Area, Northwest Territories, as Determined by Underwater Vocalizations

1990 ◽  
Vol 47 (6) ◽  
pp. 1071-1076 ◽  
Author(s):  
Holly J. Cleator ◽  
Ian Stirling

Vocalization surveys conducted in Penny Strait, Northwest Territories, indicated that before ice break-up, bearded seals (Erignathus barbatus) preferred regions of less stable ice where break-up occurred early and avoided stable, landfast ice or areas heavily used by walruses (Odobenus rosmarus). Water depth did not appear to influence distribution. Numbers of calls increased between mid-April and early June, probably because of an increase in rate of calling by individual seals. Vocalization surveys can be used to separate preferred habitats from unsuitable ones. Using a single hydrophone and our current understanding of bearded seal vocal behaviour, it is not possible to determine the absolute number of bearded seals at or near a site using vocalizations. However, it is possible to measure the relative abundance of seals for spatial and temporal comparisons.


ARCTIC ◽  
2017 ◽  
Vol 70 (4) ◽  
Author(s):  
Vladimir V. Melnikov

Information about bearded seal seasonal distribution in the Pacific Arctic is limited. Bearded seals (Erignathus barbatus Exleben, 1777) from coastal sites along the southern, eastern, and northern Chukotka Peninsula, Russian Federation, were observed most seasons during 1993 – 96, 1998 – 2000, 2002 – 05, and 2010 – 11. These observations provide spatial and temporal information about bearded seal seasonal distribution, movements, and relative numbers in the coastal zones. In winter, bearded seals aggregate on the young ice in the northern part of the Gulf of Anadyr. Numbers gradually increase during March. In springtime (April–May), bearded seals in the northern Gulf of Anadyr are relatively numerous around Nunligran (Cape Achen), but the number is highly variable across years. During spring bearded seals move eastward along the coast from the northern part of the Gulf of Anadyr towards the Bering Strait and then to the north, as the marginal ice edge zone retreats north. These movements to the east and north continue in ice-free water, and by August, the spring migration of bearded seals along the coast of the Chukotka Peninsula ends. In the summer months of August and September, few bearded seals are present in this coastal zone. The southward autumn migration of bearded seals is not evident near the coast, which suggests that it occurs farther from shore.



2000 ◽  
Vol 78 (8) ◽  
pp. 1408-1418 ◽  
Author(s):  
Bjørn A Krafft ◽  
Christian Lydersen ◽  
Kit M Kovacs ◽  
Ian Gjertz ◽  
Tore Haug

This study documents activity patterns and diving behaviour of four bearded seal (Erignathus barbatus) mothers during the lactation period. The females spent 8 ± 3% (mean ± SD) of their time hauled out on the ice and 92 ± 3% in the water. Approximately half of their time was spent diving. During the study 15 077 dives were recorded. The duration of dives was 2.0 ± 2.3 min and diving depth was 17.2 ± 22.5 m (maximum 18.7 min and 288 m, respectively). Haulout periods occurred 3 ± 2 times per day (duration = 44.0 ± 98.1 min). The overall distance swum per day was 48.1 ± 23.2 km. Three dive types were differentiated using a combination of hierarchical and k-means clustering, one V-shaped grouping and two U-shaped groupings. The most common dive type was U1; these dives were the deepest and longest type (depth = 28 ± 32 m, duration = 185 ± 146 s), and bottom time occupied a significant fraction of the total dive time (120 ± 120 s). These dives are likely foraging dives. Lactation is energetically demanding for bearded seals, and females do forage while they have dependent pups.



1989 ◽  
Vol 67 (8) ◽  
pp. 1900-1910 ◽  
Author(s):  
Holly J. Cleator ◽  
Ian Stirling ◽  
T. G. Smith

The underwater vocalizations of bearded seals (Erignathus barbatus) were recorded between March and June in 1979, 1982, and 1983 at six sites in the Arctic. In total, 970 trills were measured for temporal and spectral characteristics and then classified as one of six types. Trills were narrow in bandwidth and frequency modulated. The repertoires of vocalizing bearded seals varied amongst the six recording sites. Between-site differences in temporal and spectral features, call use, and sequential organization were measured. The results suggest that bearded seals may be relatively sedentary and that geographically different vocal repertoires may be characteristic of discrete breeding stocks. A prominent daily cycle in rate of calling during April and May was found at two sites; rate of calling was higher during the early morning hours (i.e., 03:00–04:00 sun time) than at other times of the day. No distinct temporal cycle occurred during late May and early June. Rate of calling appeared to be negatively correlated with pattern of haul out. In simultaneous recordings, a few (13 of 156) bearded seal trills were recorded up to a distance of 25 km underwater.



1997 ◽  
Vol 54 (4) ◽  
pp. 914-921 ◽  
Author(s):  
N J Lunn ◽  
I Stirling ◽  
S N Nowicki

We flew a medium-altitude, systematic, strip-transect survey for ringed (Phoca hispida) and bearded seals (Erignathus barbatus) over western Hudson Bay in early June 1994 and 1995. The mean density (per square kilometre) of ringed seals hauled out on the ice was four times higher in 1995 (1.690) than in 1994 (0.380). The 1994 survey appeared to underestimate seal abundance because it was flown too late. Ringed seals preferred high ice cover habitat (6 + /8 ice) and, within this habitat, favoured cracking ice and large floes. We found no consistent effect of either wind or cloud cover on habitat preference. We estimated a total of 1980 bearded seals and 140<|>880 ringed seals hauled out on the sea ice in June 1995. A recent review of the relationship between ringed seal and polar bear (Ursus maritimus) populations suggests that a visible population of this size should support a population of up to 1300 polar bears, which is in general agreement with the current estimate of 1250-1300 bears in western Hudson Bay.



Polar Biology ◽  
2021 ◽  
Author(s):  
Samuel M. Llobet ◽  
Heidi Ahonen ◽  
Christian Lydersen ◽  
Jørgen Berge ◽  
Rolf Ims ◽  
...  

AbstractMale bearded seals (Erignathus barbatus) use vocal displays to attract females and to compete with other males during the mating season. This makes it possible to monitor breeding populations of this species using passive acoustic monitoring (PAM). This study analysed year-round acoustic data records from AURAL instruments in Svalbard (Norway) to investigate seasonal variation in the acoustic presence of male bearded seals and the phenology of different call types (long, step and sweep trills) at three sites representing a variety of habitats with varied ice conditions. Male bearded seals vocalized for an extended period at a drift-ice site (Atwain; January–July) north of Spitsbergen, while the vocal season was shorter at a High Arctic land-fast-ice site (Rijpfjorden; February–June) and shorter yet again at a west-coast site that has undergone dramatic reductions in sea ice cover over the last 1.5 decades (Kongsfjorden; April–June). Generalized Additive Models showed marked seasonal segregation in the use of different trill types at Atwain, where call rates reached 400 per h, with long trills being the most numerous call type. Modest segregation of trill types was seen at Rijpfjorden, where call rates reached 300 per h, and no segregation occurred in Kongsfjorden (peak call rate 80 per h). Sea ice cover was available throughout the vocal season at Atwain and Rijpfjorden, while at Kongsfjorden peak vocal activity (May–June) occurred after the sea ice disappeared. Ongoing climate warming and sea ice reductions will likely increase the incidence of such mismatches and reduce breeding habitat for bearded seals.



1996 ◽  
Vol 77 (4) ◽  
pp. 1085-1091 ◽  
Author(s):  
K. M. Kovacs ◽  
C. Lydersen ◽  
I. Gjertz


1996 ◽  
Vol 166 (7) ◽  
pp. 405-411 ◽  
Author(s):  
C. Lydersen ◽  
K. M. Kovacs ◽  
M. O. Hammill ◽  
I. Gjertz


Polar Biology ◽  
2020 ◽  
Vol 43 (11) ◽  
pp. 1681-1691 ◽  
Author(s):  
Jillian M. Sills ◽  
Colleen Reichmuth ◽  
Brandon L. Southall ◽  
Alex Whiting ◽  
John Goodwin


2019 ◽  
Vol 36 (1) ◽  
pp. 276-284 ◽  
Author(s):  
Kit M. Kovacs ◽  
Bjørn A. Krafft ◽  
Christian Lydersen


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