Diet of Ringed Seals (&lt;i&gt;Phoca Hispida&lt;/i&gt;) in a Fjord of West Svalbard

Węsławski, Jan Marcin; Ryg, Morten; Smith, Thomas G.; Øritsland, Nils Are

doi:10.14430/arctic1279

Cited by 88 publications

(72 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These seals occur in the archipelago all year round, but are most numerous during winter to early summer when there is ice in the fjords and bays. Ringed seals are opportunistic feeders, preying on a wide variety of pelagic, benthic and ice associated fauna (Gjertz and Lydersen, 1986;Weslawski et al, 1994). The bearded seal (Erignathus barbatus) is the largest of the northern phocid seals, with adult lengths of about 230 cm and weighing on an average 270e275 kg , with maximum recordings well over 400 kg.…”

Section: Studied Seal Species and Model Parameterisationmentioning

confidence: 99%

Probabilistic biokinetic modelling of radiocaesium uptake in Arctic seal species: verification of modelled data with empirical observations

Brown

Dowdall

Gwynn

et al. 2006

Journal of Environmental Radioactivity

View full text Add to dashboard Cite

The necessity to provide information about radionuclide concentrations in Arctic marine species has been heightened in recent years due to a number of accidents in Arctic regions involving nuclear vessels and the presence of a large number of potential radioactive contamination sources. The provision for such information is largely dependant on the use of radionuclide uptake and transfer models. The uptake of radionuclides in Arctic seal species in this study has been modelled using a probabilistic biokinetic approach. In this paper, model results are compared with empirical data from relevant samples taken within the Arctic region. Results indicate that the model performs well when estimating concentrations of 137 Cs in two seal species for both median values and reproduction of the distribution of data values, but not as well for a third seal species. Likely factors affecting the results are the probability density functions used for the input parameters.

show abstract

Section: Studied Seal Species and Model Parameterisationmentioning

confidence: 99%

Probabilistic biokinetic modelling of radiocaesium uptake in Arctic seal species: verification of modelled data with empirical observations

Brown

Dowdall

Gwynn

et al. 2006

Journal of Environmental Radioactivity

View full text Add to dashboard Cite

show abstract

“…1966, Lowry et al 1980, Popov 1982, Weslawski et al 1994. The ringed seals in a given area typi-cally prey on no more than 10-15 prey species, and they tend to focus on only two to four of these (We slaw ski et al 1994).…”

Section: Feedingmentioning

confidence: 99%

“…Most prey fishes are 5-lOcm long; most prey crustaceans, 2-6cm long. The maximal prey size is about 20cm (Weslawski et al 1994).…”

Section: Feedingmentioning

confidence: 99%

“…can be an important component of the diet around Svalbard in spring (Weslawski et al 1994). The spring diet in northwestern Svalbard consists mainly of polar cod, decapods and larger amphipods (Gjertz and Lydersen 1986a); the schizopod Thysanoessa inermis ("krill") also contributes significantly to the diet in Kongsfjorden, particularly in summer and autumn (Weslawski et al 1994). In Southwest Greenland capelin (Mallotus vi/-losus), redfish (Sebastes spp.)…”

Section: Feedingmentioning

confidence: 99%

See 1 more Smart Citation

Distribution, abundance and biology of ringed seals (<i>Phoca hispida</i>): an overview

Reeves

1998

NAMMCOSP

View full text Add to dashboard Cite

The ringed seal (Phoca hispida) has a circumpolar Arctic distribution. Because of its great importance to northern communities and its role as the primary food of polar bears (Ursus maritimus) the ringed seal has been studied extensively in Canada, Alaska, Russia, Svalbard and Greenland as well as in the Baltic Sea and Karelian lakes. No clear-cut boundaries are known to separate ringed seal stocks in marine waters. Adult seals are thought to be relatively sedentary, but sub-adults sometimes disperse over long distances. Stable ice with good snow cover is considered the most productive habitat although production in pack ice has been little studied. Populations appear to be structured so that immature animals and young adults are consigned to sub-optimal habitat during the spring pupping and breeding season. Annual production in ringed seal populations, defined as the pup percentage in the total population after the late winter pupping season, is probably in the order of 18-24%. Most ~stimates of maximum sustainable yield are in the order of 7%.The world population of ringed seals is at least a few million. Methods of abundance estimation have included aerial surveys, dog searches and remote sensing of lairs and breathing holes, acoustic monitoring, correlation analysis by reference to sizes of polar bear populations, and inference from estimated energy requirements of bear populations. Aerial strip survey has been the method of choice for estimating seal densities over large areas. Adjustment factors to account for seals not hauled out at the time of the survey, for seals that dove ahead of the aircraft, and for seals on the ice within the surveyed strip but not detected by the observers, are required for estimates of absolute abundance.Male and female ringed seals are sexually mature by 5-7 years of age (earlier at Svalbard). Pupping usually occurs in March or early April and is followed by 5-7 weeks of lactation. Breeding takes place in mid to late May, and implantation is delayed for about 3 months. In at least some parts of their range, ringed seals feed mainly on schooling gadids from late autumn through early spring and on benthic crustaceans and polar cod (Boreogadus saida) from late spring through summer. Little feeding is done during the moult, which takes place in late spring and early summer. Pelagic crustaceans offshore and mysids inshore become important prey in late summer and early autumn in some areas. Ringed seals have several natural predators, the most important of which is the polar bear in most arctic regions. Arctic foxes (Alopex lagopus) kill a large percentage of pups in some areas.From a conservation perspective, the ringed seal appears to be secure. Levels of exploitation of arctic populations have usually been considered sustainable, except in the Okhotsk Sea. Large fluctuations in production of ringed seals in the Beaufort Sea and Amundsen Gulf are thought to be driven by natural variability in environmental conditions. While concern has been expressed about the potential imp...

show abstract

“…In another analysis of ringed seal stomach contents from Kongsfjorden and the drifting pack ice of the eastern part of Svalbard, polar cod and crustaceans such as Pandalus borealis, Parathemisto libellula and Thysanoessa inermis were the most important prey species, and a total of 24 different prey taxa were identified (Weslawski et al 1994). This material was collected in the period from February to September, comprising 115 seals from Kongsfjorden and 19 from eastern Svalbard.…”

Section: Feedingmentioning

confidence: 99%

Status and biology of ringed seals (<i>Phoca hispida</i>) in Svalbard

Lydersen

1998

NAMMCOSP

View full text Add to dashboard Cite

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 t*en 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 aven~ge of 4.6kg. They are nursed for about 39 days, and weaned at an average body mass of around 22kg. 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 127.8cm, and 52.6 and 59.9kg, respectively. The maximum values recorded for lengths of males and females in Svalbard are 157cm and 107kg, 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 the water prior to weaning. They are capable of diving for up to 12min and dive to the bottom of the study areas (max. 89m). Nursing females spend more than 80% of their time in the water. Maximum recorded dive duration for mothers was 21.2min. In order to produce a weaned pup, the net energy expenditure for a ringed seal mother is 1,073MJ. This energy value corresponds to the consumption of 185kg of polar cod or 282kg of P. libellula. The annual gross energy consumption for adult males and females is calculated to be 5,600MJ and 7,300MJ, 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.

show abstract

Diet of Ringed Seals (<i>Phoca Hispida</i>) in a Fjord of West Svalbard

Cited by 88 publications

References 9 publications

Probabilistic biokinetic modelling of radiocaesium uptake in Arctic seal species: verification of modelled data with empirical observations

Probabilistic biokinetic modelling of radiocaesium uptake in Arctic seal species: verification of modelled data with empirical observations

Distribution, abundance and biology of ringed seals (<i>Phoca hispida</i>): an overview

Status and biology of ringed seals (<i>Phoca hispida</i>) in Svalbard

Contact Info

Product

Resources

About