Stable ringed seal (Pusa hispida) demography despite significant habitat change in Svalbard, Norway

Ringed seals, which are small phocid seals, range across the circumpolar Arctic, and have evolved in close association with sea ice and depend on it for all aspects of their life history. This research study compares age structure, reproductive parameters, body size and condition during three time periods—1981–82 (n = 277), 2002–04 (n = 272) and 2012–18 (n = 212)—to study potential changes in demography in ringed seals in western Svalbard, Norway, an area that has undergone dramatic changes in sea-ice conditions during recent decades. Age distributions for the three time periods were similar, with the exception that the most recent period had a higher proportion of young animals. Age at sexual maturity for both sexes was similar for the two most recent periods, both being lower than in the 1980s. Ovulation rates did not vary significantly among the three periods (range 0.86–0.94). Pregnancy rates were only available for the most recent study period (0.71); this value falls within the range reported from other Arctic regions. Body length showed no clear temporal patterns; males were slightly longer in the most recent period, while females were slightly longer in the first period. Data from May in all periods suggest that body condition has not varied significantly through time. In conclusion, although the ringed seal breeding habitat in Svalbard has declined significantly in recent decades, demographic parameters appear to be largely unaffected. Life-history plasticity in combination with a small-scale regional variation in environmental conditions might explain the lack of changes in demography over time.

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Long-term, Harvest-based Monitoring of Ringed Seal Body Condition and Reproduction in Canada’s Western Arctic: An Update through 2019 + Supplementary Appendix 1 (See Article Tools)

ARCTIC ◽

10.14430/arctic70428 ◽

2020 ◽

Vol 73 (2) ◽

pp. 206-220

Author(s):

Lois A. Harwood ◽

Thomas G. Smith ◽

John Alikamik ◽

Emma Alikamik ◽

Ellen V. Lea ◽

...

Keyword(s):

Sea Ice ◽

Body Condition ◽

Temporal Trend ◽

Open Water ◽

Ringed Seal ◽

Breeding Habitat ◽

Ringed Seals ◽

Western Arctic ◽

Fast Ice ◽

Spring Sea Ice

The circumpolar Arctic ringed seal (Pusa hispida) occupies its fast-ice breeding habitat for four to five months during winter and the pack ice or open water of adjacent areas for the rest of the year. From 1971 – 78 and 1992 – 2019, we sampled approximately 100 ringed seals annually from western Prince Albert Sound (WPAS), the prime ringed seal fast-ice breeding habitat in Canada’s Western Arctic, adjacent to primary overwinter foraging habitat in eastern Amundsen Gulf (EAG). As our metric of body condition, we measured ventral blubber depth corrected for body size. As our metrics of reproduction, we measured the annual ovulation rate of multiparous females and percent pups in the open-water harvest. We examined these biological parameters in relation to the winter Arctic Oscillation Index (winAOI) and the timing of sea ice clearance in EAG in spring. There were no significant effects of age or sample month (June or July) on adult blubber depth, but significant sex and year effects and, in females, ovulation status effects. Across the series, as we have observed previously through 2011, there was a sustained temporal declining trend in blubber depth in adults of both sexes. There was no temporal trend in residual blubber depth, no correlation between blubber depth and sea ice clearance date in EAG, and a quasi-cyclic pattern in blubber depth that tracked some of the phases of the winAOI. Annual ovulation rates were mainly in the 80% – 100% range and correlated with percent pups in the open harvest in the same year. Three (1974, 2005, 2012) of the 36 y experienced reproductive failures, when over 50% of the multiparous females failed to ovulate. In each case, ovulation rates returned to normal within 1 – 3 y. Low annual ovulation rates were correlated with late sea ice clearance in EAG in spring, with two widespread ovulation failure events taking place in years when spring sea ice clearance was delayed by five to six weeks. The most recent ovulation failure (2012) differed in that it came in an average ice year but at the end of a six-year sequence of negative residual mean blubber depths. Earlier spring sea ice clearance in WPAS, based on the observed rate of 3.8 d per decade, would on average not result in the physical loss of sea ice for pupping in this core habitat before 2140. The mechanisms involved in the sustained declining temporal trend in body condition, linkage with some phases of the winAOI, and the temporary but episodic failures of ovulation are complex and not fully explained by either the timing of sea ice clearance or the winAOI. Until the complex mix of factors, pressures and responses are understood, our ability to predict the impacts of a changing climate on ringed seals will remain limited.

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Ringed seal (Pusa hispida) breeding habitat on the landfast ice in northwest Alaska during spring 1983 and 1984

PLoS ONE ◽

10.1371/journal.pone.0260644 ◽

2021 ◽

Vol 16 (11) ◽

pp. e0260644

Author(s):

Donna D. W. Hauser ◽

Kathryn J. Frost ◽

John J. Burns

Keyword(s):

Sea Ice ◽

Marine Mammals ◽

Environmental Changes ◽

Chukchi Sea ◽

Ringed Seal ◽

Breeding Habitat ◽

Future Research ◽

Ringed Seals ◽

Pusa Hispida ◽

Kotzebue Sound

There has been significant sea ice loss associated with climate change in the Pacific Arctic, with unquantified impacts to the habitat of ice-obligate marine mammals such as ringed seals (Pusa hispida). Ringed seals maintain breathing holes and excavate subnivean lairs on sea ice to provide protection from weather and predators during birthing, nursing, and resting. However, there is limited baseline information on the snow and ice habitat, distribution, density, and configuration of ringed seal structures (breathing holes, simple haul-out lairs, and pup lairs) in Alaska. Here, we describe historic field records from two regions of the eastern Chukchi Sea (Kotzebue Sound and Ledyard Bay) collected during spring 1983 and 1984 to quantify baseline ringed seal breeding habitat and map the distribution of ringed seal structures using modern geospatial tools. Of 490 structures located on pre-established study grids by trained dogs, 29% were pup lairs (25% in Kotzebue Sound and 33% in Ledyard Bay). Grids in Ledyard Bay had greater overall density of seal structures than those in Kotzebue Sound (8.6 structures/km2 and 7.1 structures/km2), but structures were larger in Kotzebue Sound. Pup lairs were located in closer proximity to other structures and characterized by deeper snow and greater ice deformation than haul-out lairs or simple breathing holes. At pup lairs, snow depths averaged 74.9 cm (range 37–132 cm), with ice relief nearby averaging 76 cm (range 31–183 cm), and ice deformation 29.9% (range 5–80%). We compare our results to similar studies conducted in other geographic regions and discuss our findings in the context of recent declines in extent and duration of seasonal cover of landfast sea ice and snow deposition on sea ice. Ultimately, additional research is needed to understand the effects of recent environmental changes on ringed seals, but our study establishes a baseline upon which future research can measure pup habitat in northwest Alaska.

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Characteristics of ringed seal, Phoca hispida, subnivean structures and breeding habitat and their effects on predation

Canadian Journal of Zoology ◽

10.1139/z96-100 ◽

1996 ◽

Vol 74 (5) ◽

pp. 858-874 ◽

Cited By ~ 43

Author(s):

C. M. Furgal ◽

K. M. Kovacs ◽

S. Innes

Keyword(s):

Snow Depth ◽

Function Analysis ◽

Ringed Seal ◽

Breeding Habitat ◽

Phoca Hispida ◽

Ringed Seals ◽

Arctic Foxes ◽

Ridge Height ◽

Length Width ◽

Fast Ice

Characteristics of ringed seal (Phoca hispida) subnivean structures and breeding habitat were quantified and their potential influence on predation success by polar bears (Ursus maritimus), arctic foxes (Alopex lagopus), and humans on ringed seals was investigated in Admiralty Inlet and Strathcona Sound, Northwest Territories. A total of 237 ringed seal structures were located between April and June 1991–1993 using trained dogs. Ringed seal lairs and breathing holes were concentrated in areas of deep snow, and were associated with large, thick ice ridges. Only a small percentage of the available fast-ice habitat had sufficient snow depth for lair construction each year. A discriminant function analysis used to classify structures located in 1992, using a combination of structural and habitat measurements, correctly classified 70% of structures located in 1991 and 1993 into functional groups. The length, width, internal height, and level of "tiggak," the odour of rutting male ringed seals, associated with structures were the most important descriptors separating structure types. Seventy-three percent of structures located in the study were undisturbed by predators. The mean length and width of structures entered by predators were significantly greater than those of undisturbed structures. Polar bear success decreased as snow depth and the thickness of the roof covering the structures increased. The conditions necessary for successful arctic fox predation are unclear. Inuit hunters attacked structures close to ice ridges, and ridge height and snow depth influenced their success. All predators attacked lairs having the odour of rutting male ringed seals less often than structures with no male odour.

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Assessment of claw growth-layer groups from ringed seals (Pusa hispida) as biomonitors of inter- and intra-annual Hg, δ15N, and δ13C variation

Canadian Journal of Zoology ◽

10.1139/z11-047 ◽

2011 ◽

Vol 89 (9) ◽

pp. 774-784 ◽

Cited By ~ 17

Author(s):

Elizabeth O. Ferreira ◽

Lisa L. Loseto ◽

Steven H. Ferguson

Keyword(s):

Life History ◽

Marine Mammals ◽

Ringed Seal ◽

The Body ◽

Conservation Strategies ◽

Growth Layer ◽

Annual Variations ◽

Ringed Seals ◽

Pusa Hispida ◽

Layer Groups

The ringed seal ( Pusa hispida (Schreber, 1775)) is a sentinel species of arctic marine mammals; therefore, methods to monitor its life-history changes are crucial to establish effective conservation strategies. We evaluate the potential use of claws of ringed seals as a proxy for counts of tooth growth-layer groups (age) and a biomonitor of total mercury burden (THg) and diet (stable isotope ratios expressed as δ15N and δ13C). The count of claw growth-layer groups was indicative of age up to 8 years and we infer differentiation of dark and light annuli as being associated with the spring moult. No differences of THg, δ15N, or δ13C were observed among flipper digits. The proximal claw annulus representing the most recent growth had δ13C values that were correlated to both muscle and liver δ13C, supporting the use of claws to monitor visceral δ13C. Claw log10THg from the proximate annulus was significantly correlated to liver and whisker log10THg, while significant interannual THg accumulation was observed in 18 of 32 seals ≥4 years, suggesting the claws receive and disperse Hg from active tissues of the body. Results support the use of claw tissue from ringed seal to provide a chronological record of inter- and intra-annual variations representing seal diet, contaminant load, and life history.

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Evaluating breeding habitat and populations of ringed seals Phoca hispida in Svalbard fjords

Polar Record ◽

10.1017/s0032247400012614 ◽

1991 ◽

Vol 27 (162) ◽

pp. 223-228 ◽

Cited By ~ 15

Author(s):

Christian Lydersen ◽

Morten Ryg

Keyword(s):

Condition Factor ◽

Ice Cover ◽

Ringed Seal ◽

Stratified Sampling ◽

Breeding Habitat ◽

Phoca Hispida ◽

Ringed Seals ◽

Breeding Habitats ◽

Breeding Condition ◽

Areal Variation

AbstractIn Tempelfjorden and Sassenfjorden, Svalbard, 12 March to4 April 1990, a Siberian husky dog was used to detect ringed seal breathing holes in the ice, using random stratified sampling to sample 20% (40 km2) of the total area. The area was estimated to contain 997 ringed seal breathing holes, corresponding to 293 ringed seals. A maximum of 185 pups were born in the area. A breeding condition factor was constructed to enable comparisons of yearly and areal variation in ice cover and precipitation within ringed seal breeding habitats.

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

Polar Biology ◽

10.1007/s00300-021-02874-9 ◽

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.

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Deep Learning Convolutional Neural Network Applying for the Arctic Acoustic Tomography Current Inversion Accuracy Improvement

Journal of Marine Science and Engineering ◽

10.3390/jmse9070755 ◽

2021 ◽

Vol 9 (7) ◽

pp. 755

Author(s):

Kangkang Jin ◽

Jian Xu ◽

Zichen Wang ◽

Can Lu ◽

Long Fan ◽

...

Keyword(s):

Neural Network ◽

Deep Learning ◽

Sea Ice ◽

Convolutional Neural Network ◽

Arctic Sea Ice ◽

The Arctic ◽

Small Scale ◽

Acoustic Tomography ◽

Arctic Sea ◽

Current Inversion

Warm current has a strong impact on the melting of sea ice, so clarifying the current features plays a very important role in the Arctic sea ice coverage forecasting study field. Currently, Arctic acoustic tomography is the only feasible method for the large-range current measurement under the Arctic sea ice. Furthermore, affected by the high latitudes Coriolis force, small-scale variability greatly affects the accuracy of Arctic acoustic tomography. However, small-scale variability could not be measured by empirical parameters and resolved by Regularized Least Squares (RLS) in the inverse problem of Arctic acoustic tomography. In this paper, the convolutional neural network (CNN) is proposed to enhance the prediction accuracy in the Arctic, and especially, Gaussian noise is added to reflect the disturbance of the Arctic environment. First, we use the finite element method to build the background ocean model. Then, the deep learning CNN method constructs the non-linear mapping relationship between the acoustic data and the corresponding flow velocity. Finally, the simulation result shows that the deep learning convolutional neural network method being applied to Arctic acoustic tomography could achieve 45.87% accurate improvement than the common RLS method in the current inversion.

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Accurate age estimation in small-scale societies

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1619583114 ◽

2017 ◽

Vol 114 (31) ◽

pp. 8205-8210 ◽

Cited By ~ 8

Author(s):

Yoan Diekmann ◽

Daniel Smith ◽

Pascale Gerbault ◽

Mark Dyble ◽

Abigail E. Page ◽

...

Keyword(s):

Life History ◽

Bayesian Approach ◽

Age Estimation ◽

Human Life ◽

The Philippines ◽

Monte Carlo Algorithm ◽

Small Scale ◽

Hunter Gatherers ◽

Cultural Life ◽

Ranking Order

Precise estimation of age is essential in evolutionary anthropology, especially to infer population age structures and understand the evolution of human life history diversity. However, in small-scale societies, such as hunter-gatherer populations, time is often not referred to in calendar years, and accurate age estimation remains a challenge. We address this issue by proposing a Bayesian approach that accounts for age uncertainty inherent to fieldwork data. We developed a Gibbs sampling Markov chain Monte Carlo algorithm that produces posterior distributions of ages for each individual, based on a ranking order of individuals from youngest to oldest and age ranges for each individual. We first validate our method on 65 Agta foragers from the Philippines with known ages, and show that our method generates age estimations that are superior to previously published regression-based approaches. We then use data on 587 Agta collected during recent fieldwork to demonstrate how multiple partial age ranks coming from multiple camps of hunter-gatherers can be integrated. Finally, we exemplify how the distributions generated by our method can be used to estimate important demographic parameters in small-scale societies: here, age-specific fertility patterns. Our flexible Bayesian approach will be especially useful to improve cross-cultural life history datasets for small-scale societies for which reliable age records are difficult to acquire.

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Population parameters of ringed seals (Phoca hispida Schreber, 1775) in the Svalbard area

Canadian Journal of Zoology ◽

10.1139/z87-162 ◽

1987 ◽

Vol 65 (4) ◽

pp. 1021-1027 ◽

Cited By ~ 38

Author(s):

Christian Lydersen ◽

Ian Gjertz

Keyword(s):

Sex Ratio ◽

Ringed Seal ◽

Adult Males ◽

Population Parameters ◽

Phoca Hispida ◽

Age Class ◽

Ringed Seals ◽

Males And Females ◽

The Mean ◽

Sexually Mature

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.

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The breeding habitat of the ringed seal (Phoca hispida). The birth lair and associated structures

Canadian Journal of Zoology ◽

10.1139/z75-155 ◽

1975 ◽

Vol 53 (9) ◽

pp. 1297-1305 ◽

Cited By ~ 125

Author(s):

Thomas G. Smith ◽

Ian Stirling

Keyword(s):

Ursus Maritimus ◽

Ringed Seal ◽

Breeding Habitat ◽

Polar Bears ◽

Alopex Lagopus ◽

Phoca Hispida ◽

Arctic Foxes ◽

Different Types ◽

Amundsen Gulf

The subnivean lairs of the ringed seal (Phoca hispida) were studied in the Amundsen Gulf and Prince Albert Sound areas from 1971 through 1974. The structure of several different types of lairs are described. The existence of a birth-lair complex consisting of several closely adjacent lairs appears likely. The spacial distribution of lairs and lair types found on refrozen leads and in pressure ridges is described. Lairs were more abundant in inshore ice than in offshore ice. The function of subnivean lairs appears to be to provide thermal shelter, especially for neonate seals, and protection from predation by arctic foxes (Alopex lagopus) and polar bears (Ursus maritimus).

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