scholarly journals Growth and population parameters of ringed seals (Pusa hispida) from Svalbard, Norway, 2002–2004

2006 ◽  
Vol 63 (6) ◽  
pp. 1136-1144 ◽  
Author(s):  
Bjørn A. Krafft ◽  
Kit M. Kovacs ◽  
Anne Kirstine Frie ◽  
Tore Haug ◽  
Christian Lydersen
Keyword(s):  
Ringed Seal ◽  
The Arctic ◽  
Strong Impact ◽  
Climate Change Scenarios ◽  
Population Parameters ◽  
Ringed Seals ◽  
Asymptotic Values ◽  
Seal Population ◽  
Pusa Hispida ◽  
Sexually Mature

AbstractSamples were collected in Svalbard, Norway, during April and May 2002–2004 from 272 ringed seals (Pusa hispida; 62.5% males, 37.5% females) to study growth and population parameters. The age of the animals ranged from 1 to 32 years. Asymptotic values for standard length and body mass were 127.7 ± 1.6 (s.e.) cm and 69.0 ± 2.7 kg for males (maxima: 144 cm and 92 kg) and 127.6 ± 2.3 cm and 68.9 ± 2.5 kg for females (maxima: 141 cm and 91 kg). All animals were sexually mature at an age ≥6 years and the ovulation rate was 0.86. Mean Age at Maturity (MAM) was 4.2 ± 0.2 years for males and 3.5 ± 0.3 years for females, values significantly lower than calculated for ringed seals from the same area 20 years ago. This change in MAM suggests that either the prey base for ringed seals in the area has increased or alternatively that the density of ringed seals has declined, such that more resources are available per capita. If the climate of the Arctic changes in the manner predicted by a host of climate-change scenarios, it is likely to have a strong impact on ringed seal populations in future, although there are no data to suggest that dramatic changes have taken place yet in fish and invertebrate populations in the Svalbard area. Although cause-and-effect cannot be firmly established, there is a possibility that the substantial increase in the number of polar bears (Ursus maritimus) over the past 20 years, since hunting the species in Svalbard ceased in 1973, may have played a role in the observed change in the ringed seal population.

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

1987 ◽  
Vol 65 (4) ◽  
pp. 1021-1027 ◽  
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.

scholarly journals Status and biology of ringed seals (Phoca hispida) in Svalbard

1998 ◽  
Vol 1 ◽  
pp. 46 ◽  
Author(s):  
Christian Lydersen
Keyword(s):  
Body Mass ◽  
Dive Duration ◽  
Early Spring ◽  
Ringed Seal ◽  
The Arctic ◽  
Polar Cod ◽  
Net Energy ◽  
Adult Males ◽  
Ringed Seals ◽  
Males And Females

The ringed seal is the most abundant mammal in the Svalbard area. Annual pup production in this area is estimated to be 20,000. No systematic harvest records exist, but some few hundred seals are taken annually, mainly for dog food. The ringed seals in Svalbard are protected from hunting in the period 15 March - 15 April. Peak pupping season is the first week of April. New-born ringed seals weigh an average of 4.6 kg. They are nursed for about 39 days, and weaned at an average body mass of around 22 kg. During the period of maternal care pups consume a total of about 54 litres of milk, that is composed of approximately 38% fat and 10% protein. Asymptotic standard lengths and body masses for adult ringed seal males and females are 131.5 and 127.8 cm, and 52.6 and 59.9 kg,respectively. The maximum values recorded for lengths of males and females in Svalbard are 157 cm and 107 kg, respectively. There is marked seasonal variation in body mass in both sexes with the highest mass records being recorded in early spring before pupping occurs, and with minimum values in the summer after the breeding and moulting seasons. The observed variation in mass is mainly due to changing blubber thickness of the seals. Ringed seal males attain sexual maturity at the age of 5 - 7 years, while females reach maturity when they are 3-5 years of age. The oldest seal collected in Svalbard was aged 45. Ringed seals in the Svalbard area feed on a variety of prey organisms, the most important of which are polar cod (Boreogadus saida) and the crustaceans Parathemisto libellula, Thysanoessa inermis and Pandalus borealis. Ringed seal pups start diving during the nursing period while they are still white-coats, and spend about 50% of the time in thewater prior to weaning. They are capable of diving for up to 12min and dive to the bottom of the study areas (max. 89 m). Nursing females spend more than 80% of their time in the water. Maximum recorded dive duration for mothers was 21.2 min. In order to produce a weaned pup, the net energy expenditure for a ringed seal mother is 1,073 MJ. This energy value corresponds to the consumption of 185 kg of polar cod or 282 kg of P. libellula. The annual gross energy consumption for adult males and females is calculated to be 5,600 MJ and 7,300 MJ, respectively. The main predators of ringed seals in Svalbard are polar bears (Ursus maritimus) and Arctic foxes (Alopex lagopus). In addition, both glaucous gulls (Larus hyperboreus) and walruses (Odobenus rosmarus) are documented as predators of ringed seals in this area. Heavy predation pressure is probably the main factor explaining why pups of this species start diving at such a young age, why they have access to so many breathing holes (8.7 on average) and why they keep their white coat long after its thermoregulatory properties have vanished. Pollution levels in ringed seals from Svalbard are, generally speaking, similar to levels in other areas of the Arctic.

scholarly journals Variation in body size of ringed seals (Pusa hispida hispida) across the circumpolar Arctic: evidence of morphs, ecotypes or simply extreme plasticity?

2021 ◽  
Vol 40 ◽  
Author(s):  
Kit M. Kovacs ◽  
John Citta ◽  
Tanya Brown ◽  
Rune Dietz ◽  
Steve Ferguson ◽  
...  
Keyword(s):  
Body Size ◽  
The Arctic ◽  
Age At Maturity ◽  
Adaptation To Climate Change ◽  
Eastern Canada ◽  
Genetic Studies ◽  
Ringed Seals ◽  
Pusa Hispida ◽  
Potential Adaptation ◽  
Circumpolar Arctic

The ringed seal is a small phocid seal that has a northern circumpolar distribution. It has long been recognized that body size is variable in ringed seals, and it has been suggested that ecotypes that differ in size exist. This study explores patterns of body size (length and girth) and age-at-maturity across most of the Arctic subspecies’ range using morphometric data from 35 sites. Asymptotic lengths varied from 113 to 151 cm, with sites falling into five distinct size clusters (for each sex). Age-at-maturity ranged from 3.1 to 7.4 years, with sites that had early ages of sexual maturity generally having small length-at-maturity and small final body length. The sexes differed in length at some sites, but not in a consistent pattern of dimorphism. The largest ringed seals occurred in western Greenland and eastern Canada, and the smallest occurred in Alaska and the White Sea. Latitudinal trends occurred only within sites in the eastern Canadian Arctic. Girth (with length and season accounted for) was also highly variable but showed no notable spatial pattern; males tended to be more rotund than females. Genetic studies are needed, starting with the “giants” at Kangia (Greenland) and in northern Canada to determine whether they are genetically distinct ecotypes. Additional research is also needed to understand the ecological linkages that drive the significant regional size differences in ringed seals that were confirmed in this study, and also to understand their implications with respect to potential adaptation to climate change.

Pathological changes of stomach in ringed seal (Pusa hispida) from Arviat (North Canada) caused by anisakid nematodes

2013 ◽  
Vol 16 (1) ◽  
pp. 63-67
Author(s):  
Z. Sołtysiak ◽  
M. Simard ◽  
J. Rokicki
Keyword(s):  
Mononuclear Cells ◽  
Gastric Wall ◽  
Ringed Seal ◽  
Gastric Lesions ◽  
Ringed Seals ◽  
Pseudoterranova Decipiens ◽  
Mucosal Layer ◽  
Pusa Hispida ◽  
Contracaecum Osculatum ◽  
Anisakid Nematodes

Abstract This is a report of lesions associated with the nematodes (Anisakidae) from the stomach of ringed seals (Pusa hispida). On thirty one examined ringed seals from Arviat, thirteen were infected by 1 to 24 anisakids. Identification of nematodes from their stomachs showed two species; Contracaecum osculatum (sensu lato) (79 specimens) and Pseudoterranova decipiens (sensu lato) (11 specimens). In the gastric sections with parasites, larvae and adults of nematodes were present mainly in the fundic portion of the stomach. The anterior parts of the nematodes were embedded in mucosa and submucosa. Anisakids were associated with ulcerous gastric lesions and raised inflammatory areas in the stomachs. The histological examination of a sample taken from the tissue surrounding anisakids revealed the presence of more or less confluent focal necrotic areas. Most small petechial hemorrhages were located in the mucosal layer of the gastric wall and were surrounded by inflammatory mononuclear cells such as lymphocytes, histiocytes, eosinophils and fibroblasts. The Anisakidae larvae in the stomach caused atrophy of glands, hemorrhaging and eosinophilic infiltrations that consequently healed, creating fibrotic scars.

Comparison between spring and autumn infection by Corynosoma (Acanthocephala) in the ringed seal Pusa hispida in the Bothnian Bay of the Baltic Sea

Parasitology ◽  
1981 ◽  
Vol 82 (2) ◽  
pp. 287-296 ◽  
Author(s):  
Eero Helle ◽  
E. Tellervo Valtonen
Keyword(s):  
Baltic Sea ◽  
Feeding Habits ◽  
Ringed Seal ◽  
The Other ◽  
The Baltic Sea ◽  
Rate Of Development ◽  
Ringed Seals ◽  
Pusa Hispida ◽  
The Baltic ◽  
Bothnian Bay

SUMMARYCorynosoma spp. (Acanthocephala) infection in ringed seals (Pusa hispida) is compared in spring and in autumn in the Bothnian Bay, northern Baltic Sea. The material consists of more than 13400 specimens: 7590 from the intestines of 13 seals captured in April and May 1978 and 5850 from 29 seals captured in October and November.Corynosoma strumosum infection had approximately the same intensity in spring and autumn (mean 76 and 66 individuals/infected seal, maxmum 313 and 324 individuals, respectively). C. semerme specimens, on the other hand, were 37 times more numerous in spring than in autumn (504 compared with 136/infected seal, maximum 1700 and 1230 individuals, respectively). The ratio of C. strumosum to C. semerme was 1:6·3 in spring and 1:2·0 in autumn, as calculated from the total material. Corynosoma infection was more recent on average in spring than in autumn, as judged both from the proportion of males and immature females and from the distribution of C. semerme in the intestine. The feeding habits of the ringed seals and the rate of development of Corynosoma infection are discussed.

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

2011 ◽  
Vol 89 (9) ◽  
pp. 774-784 ◽  
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.

scholarly journals Warming Water in Arctic Terrestrial Rivers under Climate Change

2017 ◽  
Vol 18 (7) ◽  
pp. 1983-1995 ◽  
Author(s):  
Hotaek Park ◽  
Yasuhiro Yoshikawa ◽  
Daqing Yang ◽  
Kazuhiro Oshima
Keyword(s):  
Climate Change ◽  
Warming Trend ◽  
The Arctic ◽  
Future Climate Change ◽  
Biogeochemical Model ◽  
Strong Impact ◽  
Climate Change Scenarios ◽  
Modeling Framework ◽  
Channel Network ◽  
Arctic Rivers

Abstract Recent years have seen an obvious warming trend in the Arctic. Streamflow and water temperature Tw are important parameters representing the changes of Arctic rivers under climate change. However, few quantitative assessments of changes in river Tw have been conducted at the pan-Arctic scale. To carry out such an assessment, this study used a modeling framework combining a land process model [the coupled hydrological and biogeochemical model (CHANGE)] with models of river discharge Q, ice cover, and Tw dynamics. The Tw model was improved by incorporating heat exchange at the air–water interface and heat advection from upstream through the channel network. The model was applied to pan-Arctic terrestrial rivers flowing into the Arctic Ocean over the period 1979–2013 and quantitatively assessed trends of Tw at regional and pan-Arctic scales. The simulated Tw values were consistent with observations at the mouths of major pan-Arctic rivers. The model simulations indicated a warming trend of Tw by 0.16°C decade−1 at the outlets of the pan-Arctic rivers, including widespread spatial warming consistent with increased air temperature Ta. The strong impact of Ta on Tw was verified by model sensitivity analysis based on various scenarios involving changes in the Ta and Q forcings. Finally, this study demonstrated the warming of Tw in Arctic rivers induced by Ta warming, suggesting the potential for warming Tw of Arctic rivers under future climate change scenarios.

scholarly journals Spring distribution of ringed seals (Pusa hispida) in Eclipse Sound and Milne Inlet, Nunavut: implications for potential ice-breaking activities

2019 ◽  
Vol 5 (1) ◽  
pp. 54-61 ◽  
Author(s):  
David J. Yurkowski ◽  
Brent G. Young ◽  
J. Blair Dunn ◽  
Steven H. Ferguson
Keyword(s):  
Iron Ore ◽  
Policy Decision ◽  
Resource Development ◽  
Ringed Seal ◽  
Mitigation Strategies ◽  
Decision Makers ◽  
Sea Ice Extent ◽  
Ringed Seals ◽  
Aerial Surveys ◽  
Pusa Hispida

Resource development in Arctic waters is proceeding rapidly leading to increased interactions with Arctic wildlife. As sea ice extent decreases, the demand for shipping and ice-breaking operations will expand into winter and spring with greater impact on ice-dependent pinnipeds. However, knowledge of the distribution of these species, such as ringed seals (Pusa hispida (Schreber, 1775)), during spring within areas of resource development is lacking. Baffinland Iron Mines Corporation’s Mary River iron ore port in southern Milne Inlet, Nunavut opened in 2015 with proposed ice-breaking activities in spring — an important period in ringed seal seasonal life-history. We conducted infrared and photographic aerial surveys in June 2016 and 2017 to overlay the proposed ice-breaking route with ringed seal hotspots (i.e., areas of higher density). We identified four areas of overlap where proposed ice-breaking would traverse through ringed seal hotspots: eastern and western Eclipse Sound (a ringed seal pupping ground identified by local knowledge), the middle of Milne Inlet, and southern Milne Inlet. We identified potential negative implications of spring ice-breaking operations on ringed seals such as displacement, separation of mothers and pups, destruction of resting and birth lairs, and vessel–seal collisions. Results are relevant to policy decision-makers who can develop mitigation strategies in the rapidly melting and developing Arctic.

The structure of the mature oocyte and zygote of Corynosoma semerme (Acanthocephala)

Parasitology ◽  
1982 ◽  
Vol 84 (3) ◽  
pp. 475-479 ◽  
Author(s):  
Raija Peura ◽  
E. Tellervo Valtonen ◽  
D. W. T. Crompton
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Mature Female ◽  
Mature Oocyte ◽  
Ringed Seal ◽  
Transmission Electron ◽  
Pusa Hispida ◽  
Sexually Mature

SummaryObservations made with the transmission electron microscope are described from the free ovaries of sexually mature female Corynosoma semerme (Palaeacanthocephala) from the ringed seal (Pusa hispida). The structure of the mature ovaries consists of a supporting syncytium, oogonial cells and tissue and appears to be basically similar to that already described for 4 other species of Acanthocephala representing the 3 orders of the phylum. A comparison has been made between the organization of the cytoplasm of the mature oocyte and the zygote with reference to the consequences of fertilization. A detailed description is presented of the heterogeneous inclusions that are observed in the cytoplasm of the mature oocyte but not in the zygote. The fate and possible function of the components of these inclusions is discussed.

scholarly journals The numbers of ringed seals (Phoca hispida) in Baffin Bay and associated waters

1998 ◽  
Vol 1 ◽  
pp. 181 ◽  
Author(s):  
Michael C S Kingsley
Keyword(s):  
Polar Bear ◽  
Approximate Model ◽  
Ringed Seal ◽  
Phoca Hispida ◽  
Age Classes ◽  
Field Metabolic Rate ◽  
Baffin Bay ◽  
Ringed Seals ◽  
Pack Ice ◽  
Seal Population

The size of the population of ringed seals (Phoca hispida) inhabiting Baffin Bay and associated waters was estimated by two methods. An approximate model of the energetics of the polar bear (Ursus maritimus) estimated an energetic need of about 16,000 MJ/bear per year. Modelled estimates of the energetic yield of a ringed seal population showed that a stable standing population of 140-170 ringed seals per bear would be needed to provide that much energy, assuming that all mortalities were due to polar bear predation. This result was sensitive to assumptions about the Field Metabolic Rate (FMR) of the bears and the energetic yield of individual ringed seals, but less sensitive to assumptions about relative incidence of predation on different age classes of seal or the age structure of the polar bear population. Estimated sizes of polar bear populations in Baffin Bay and associated waters (total about 4,025), and of the standing population needed to support an estimated hunter kill of 100,000 yielded a population estimate of, very roughly, 1.2 million ringed seals. Estimates of ice areas and of the density of hauled out seals from aerial surveys were used to generate another approximate figure for the ringed seal population, which was about the same. The density of seals in the pack-ice area of Baffin Bay, which is imperfectly known, has a large influence on the latter estimate.

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