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Novel terrestrial haul-out behaviour by ringed seals (Pusa hispida) in Svalbard, in association with harbour seals (Phoca vitulina).

https://arctichealth.org/en/permalink/ahliterature297161
Source
Polar Research. 36:1. 7 p.
Publication Type
Article
Date
2017
hispida) in Svalbard, in association with harbour seals (Phoca vitulina) Christian Lydersen, Jade Vaquie-Garcia, Espen Lydersen, Guttorm N. Christensen & Kit M. Kovacs To cite this article: Christian Lydersen, Jade Vaquie-Garcia, Espen Lydersen, Guttorm N. Christensen & Kit M. Kovacs (2017) Novel
  1 document  
Author
Lydersen, Christian
Vaquie-Garcia, Jade
Lydersen, Espen
Christensen, Guttorm N.
Kovacs, Kit M.
Source
Polar Research. 36:1. 7 p.
Date
2017
Language
English
Geographic Location
Norway
Publication Type
Article
File Size
1607240
Keywords
Arctic
Ringed seals
Harbour seals
Svalbard
Behavioural plasticity
Climate change
Glacier fronts
Lagoons
Sea ice
Abstract
Ringed seals (Pusa hispida) are the most ice-associated of all Arctic pinnipeds. In the Svalbard area, this species has always given birth, moulted and rested on sea ice. In addition, much of their food has been comprised of ice-associated prey. Recently, ringed seals have been reported to be using terrestrial substrates as a haul-out platform in some fjords on the west coast of Spitsbergen. In many cases the seals involved are harbour seals (Phoca vitulina), which are extending their distribution into new areas within the Svalbard Archipelago and which are being misclassified as ringed seals. However, this study reports that terrestrial haulout by ringed seals is also now taking place on rocks exposed at low tide as well as on the coastline. Recent intrusions of warm Atlantic Water (with associated prey) have extended deep into the fjords of western Spitsbergen, resulting in deteriorated ice conditions for ringed seals and expanded habitat for harbour seals. Over the last decade, ringed seals have become more and more confined in coastal areas to narrow bands in front of tidal glacier fronts where Arctic conditions still prevail. In one lagoon area, ringed seals are hauling out on intertidal mud flats in close association with harbour seals. Land can likely replace sea-ice for many of the ringed seals haul-out needs. However, for the small dry-cold adapted ringed seal pups that are normally born in snow lairs on the sea ice, terrestrial haul-out is unlikely to be a viable solution because of predation and thermoregulatory stress.
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The world’s northern most harbour seal population - How many are there?

https://arctichealth.org/en/permalink/ahliterature297160
Source
University of Tromsø, Department of Arctic and Marine Biology. 41 p.
Publication Type
Dissertation
Date
2012
The world’s northern most harbour seal population - How many are there? Benjamin Merkel BIO-3910 Master’s thesis in Biology November 2012 The world’s northern most harbour seal population - How many are there
  1 document  
Author
Merkel, Benjamin
Source
University of Tromsø, Department of Arctic and Marine Biology. 41 p.
Date
2012
Language
English
Geographic Location
Norway
Publication Type
Dissertation
File Size
1327149
Keywords
Svalbard
Harbour seal
Population survey
Abstract
This study presents the first abundance estimate for the world's northernmost harbour seal (Phoca vitulina) population, which resides in Svalbard, Norway, based on three digital stereoscopic photographic surveys conducted in 2009 and 2010. The counts from these high resolution 3D images were combined with a novel method for estimating correction factors for animals that were in the water at the time of the surveys, in which extensive behavioural data from radio-tagged harbour seals were used together with a modelled stationary age structure to estimate the proportion of seals of various age and sex classes hauled out at the times of the surveys. To detect possible seasonal shifts in age distribution between surveys, lengths of hauled out seals were measured from the stereoscopic images. No such length differences were detected; but, this may be due to a high degree of sexual dimorphism exhibited in this population. Applying the modelled correction factors, a total of 1888 (95 % CI: 1660-3023), 1742 (1381-3549) and 1812 (1656-4418) harbour seals were estimated for the surveys flown on 01 August 2009, 01 August 2010 and 19 August 2010, respectively.The similarity between the three survey estimates (despite significant differences in the number of animals actually counted on the photos from each survey effort) suggests that the variation in numbers of hauled out seals is reasonably accurately adjusted for by the correction factor model. The low population size, the limited spatial distribution of the population and its reduced genetic diversity make it vulnerable to stochastic mortality events. However, barring disease events, climate change—a major threat to many arctic marine mammals—is likely to have a positive impact on this population as more suitable habitat becomes available and competition from endemic arctic pinnipeds is reduced.
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