Underwater vocalizations of the bearded seal (Erignathus barbatus)

1989 ◽  
Vol 67 (8) ◽  
pp. 1900-1910 ◽  
Author(s):  
Holly J. Cleator ◽  
Ian Stirling ◽  
T. G. Smith
Keyword(s):  
Spectral Characteristics ◽  
Early Morning ◽  
The Arctic ◽  
Spectral Features ◽  
Bearded Seal ◽  
Daily Cycle ◽  
Sequential Organization ◽  
Erignathus Barbatus ◽  
Bearded Seals

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.

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
Keyword(s):  
Northwest Territories ◽  
Absolute Number ◽  
Bearded Seal ◽  
Vocal Behaviour ◽  
Winter Distribution ◽  
Odobenus Rosmarus ◽  
Erignathus Barbatus ◽  
Break Up ◽  
A Site ◽  
Bearded Seals

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.

scholarly journals Validation of a novel method to create temporal records of hormone concentrations from the claws of ringed and bearded seals

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Shawna A Karpovich ◽  
Larissa A Horstmann ◽  
Lori K Polasek
Keyword(s):  
Physiological Stress ◽  
Fold Increase ◽  
The Arctic ◽  
Bearded Seal ◽  
Paired Samples ◽  
Pregnancy Status ◽  
Pusa Hispida ◽  
Novel Method ◽  
As Stress ◽  
Bearded Seals

Abstract Ringed (Pusa hispida) and bearded seals (Erignathus barbatus) inhabit vast and often remote areas in the Arctic, making it difficult to obtain long-term physiological information concerning health and reproduction. These seals are experiencing climate-driven changes in their habitat that could result in physiological stress. Chronic physiological stress can lead to immunosuppression, decreased reproduction and decreased growth. Recently, keratin has become a popular matrix to measure steroid hormones, such as stress-related cortisol and reproduction-related progesterone. We developed and validated methods to extract cortisol and progesterone from the claws of adult female ringed (n = 20) and bearded (n = 3) seals using enzyme immunosorbent assays. As ringed and bearded seal claws grow, a pair of dark- and light-colored bands of keratin is deposited annually providing a guide for sampling. Two processing methods were evaluated, removal of claw material with a grinding bit or grinding followed by mechanical pulverization (102 paired samples from six claws, two each from three seals). Adding the mechanical pulverization step resulted in a 1.5-fold increase in hormone extraction. Progesterone from the proximal claw band was evaluated to biologically validate claw material as a measure of pregnancy in ringed seals (n = 14). Claws from pregnant seals had significantly higher claw progesterone concentrations than from non-pregnant seals. This suggests that the elevated progesterone associated with gestation was reflected in the claws, and that the most proximal claw band was indicative of pregnancy status at time of death. Thus, although the sample size was low and the collection dates unbalanced, this study demonstrates the potential to use claws to examine an extended time series (up to 12 yrs) of cortisol and progesterone concentrations in ringed and bearded seal claws.

scholarly journals Seasonal Movements and Relative Abundance of Bearded Seals (Erignathus barbatus) in the Coastal Waters of the Chukotka Peninsula

ARCTIC ◽  
2017 ◽  
Vol 70 (4) ◽  
Author(s):  
Vladimir V. Melnikov
Keyword(s):  
Free Water ◽  
Seasonal Distribution ◽  
Bering Strait ◽  
Coastal Zones ◽  
Bearded Seal ◽  
Edge Zone ◽  
The North ◽  
The Pacific ◽  
Erignathus Barbatus ◽  
Bearded Seals

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.

Diving behaviour of lactating bearded seals (Erignathus barbatus) in the Svalbard area

2000 ◽  
Vol 78 (8) ◽  
pp. 1408-1418 ◽  
Author(s):  
Bjørn A Krafft ◽  
Christian Lydersen ◽  
Kit M Kovacs ◽  
Ian Gjertz ◽  
Tore Haug
Keyword(s):  
Activity Patterns ◽  
Diving Behaviour ◽  
Significant Fraction ◽  
Lactation Period ◽  
Bearded Seal ◽  
Diving Depth ◽  
Erignathus Barbatus ◽  
Bearded Seals

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.

Distribution and abundance of ringed (Phoca hispida) and bearded seals (Erignathus barbatus) in western Hudson Bay

1997 ◽  
Vol 54 (4) ◽  
pp. 914-921 ◽  
Author(s):  
N J Lunn ◽  
I Stirling ◽  
S N Nowicki
Keyword(s):  
Polar Bear ◽  
Hudson Bay ◽  
Phoca Hispida ◽  
Current Estimate ◽  
Ringed Seals ◽  
Erignathus Barbatus ◽  
The Mean ◽  
Western Hudson Bay ◽  
The Relationship ◽  
Bearded Seals

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.

scholarly journals Bearded seal (Erignathus barbatus) vocalizations across seasons and habitat types in Svalbard, Norway

Polar Biology ◽  
2021 ◽  
Author(s):  
Samuel M. Llobet ◽  
Heidi Ahonen ◽  
Christian Lydersen ◽  
Jørgen Berge ◽  
Rolf Ims ◽  
...  
Keyword(s):  
Sea Ice ◽  
Generalized Additive Models ◽  
Extended Period ◽  
Ice Cover ◽  
High Arctic ◽  
Additive Models ◽  
Breeding Habitat ◽  
Breeding Populations ◽  
Erignathus Barbatus ◽  
Bearded Seals

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.

scholarly journals Birth-Site Characteristics and Prenatal Molting in Bearded Seals (Erignathus barbatus)

1996 ◽  
Vol 77 (4) ◽  
pp. 1085-1091 ◽  
Author(s):  
K. M. Kovacs ◽  
C. Lydersen ◽  
I. Gjertz
Keyword(s):  
Site Characteristics ◽  
Erignathus Barbatus ◽  
Bearded Seals

Energy intake and utilisation by nursing bearded seal (Erignathus barbatus) pups from Svalbard, Norway

1996 ◽  
Vol 166 (7) ◽  
pp. 405-411 ◽  
Author(s):  
C. Lydersen ◽  
K. M. Kovacs ◽  
M. O. Hammill ◽  
I. Gjertz
Keyword(s):  
Energy Intake ◽  
Bearded Seal ◽  
Erignathus Barbatus

scholarly journals How Sensitive are EEG Results to Preprocessing Methods: A Benchmarking Study

2020 ◽  
Author(s):  
Kay A. Robbins ◽  
Jonathan Touryan ◽  
Tim Mullen ◽  
Christian Kothe ◽  
Nima Bigdely-Shamlo
Keyword(s):  
Best Practices ◽  
General Structure ◽  
Spectral Characteristics ◽  
Low Frequency ◽  
Spectral Features ◽  
Eeg Analysis ◽  
Research Reporting ◽  
Automated Processing ◽  
Open Question

AbstractAlthough several guidelines for best practices in EEG preprocessing have been released, even those studies that strictly adhere to those guidelines contain considerable variation in the ways that the recommended methods are applied. An open question for researchers is how sensitive the results of EEG analyses are to variations in preprocessing methods and parameters. To address this issue, we analyze the effect of preprocessing methods on downstream EEG analysis using several simple signal and event-related measures. Signal measures include recording-level channel amplitudes, study-level channel amplitude dispersion, and recording spectral characteristics. Event-related methods include ERPs and ERSPs and their correlations across methods for a diverse set of stimulus events. Our analysis also assesses differences in residual signals both in the time and spectral domains after blink artifacts have been removed. Using fully automated pipelines, we evaluate these measures across 17 EEG studies for two ICA-based preprocessing approaches (LARG, MARA) plus two variations of Artifact Subspace Reconstruction (ASR). Although the general structure of the results is similar across these preprocessing methods, there are significant differences, particularly in the low-frequency spectral features and in the residuals left by blinks. These results argue for detailed reporting of processing details as suggested by most guidelines, but also for using a federation of automated processing pipelines and comparison tools to quantify effects of processing choices as part of the research reporting.

scholarly journals Mass spectral characterization of primary emissions and implications in source apportionment of organic aerosol

2020 ◽  
Vol 13 (6) ◽  
pp. 3205-3219 ◽  
Author(s):  
Weiqi Xu ◽  
Yao He ◽  
Yanmei Qiu ◽  
Chun Chen ◽  
Conghui Xie ◽  
...  
Keyword(s):  
Source Apportionment ◽  
Spectral Characteristics ◽  
Organic Aerosol ◽  
Water Soluble ◽  
Spectral Characterization ◽  
Rural Site ◽  
Spectral Features ◽  
Mass Spectral ◽  
Spectral Profiles ◽  
Primary Emissions

Abstract. Source apportionment of organic aerosol (OA) from aerosol mass spectrometer (AMS) or aerosol chemical speciation monitor (ACSM) measurements relies largely upon mass spectral profiles from different source emissions. However, the changes in mass spectra of primary emissions from AMS–ACSM with the newly developed capture vaporizer (CV) are poorly understood. Here we conducted 21 cooking, crop straw, wood, and coal burning experiments to characterize the mass spectral features of OA and water-soluble OA (WSOA) using SV-AMS and CV-ACSM. Our results show overall similar spectral characteristics between SV-AMS and CV-ACSM for different primary emissions despite additional thermal decomposition in CV, and the previous spectral features for diagnostics of primary OA factors are generally well retained. However, the mass spectral differences between OA and WSOA can be substantial for both SV-AMS and CV-ACSM. The changes in f55 (fraction of m∕z 55 in OA) vs. f57, f44 vs. f60, and f44 vs. f43 in CV-ACSM are also observed, yet the evolving trends are similar to those of SV-AMS. By applying the source spectral profiles to a winter CV-ACSM study at a highly polluted rural site in the North China Plain, the source apportionment of primary OA was much improved, highlighting the two most important primary sources of biomass burning and coal combustion (32 % and 21 %). Considering the rapidly increasing deployments of CV-ACSM and WSOA studies worldwide, the mass spectral characterization has significant implications by providing essential constraints for more accurate source apportionment and making better strategies for air pollution control in regions with diverse primary emissions.

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