The world's northern most harbour seal population - How many are there?
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 co...
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2012
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ftunivtroemsoe:oai:munin.uit.no:10037/5516 2023-05-15T14:31:41+02:00 The world's northern most harbour seal population - How many are there? Merkel, Benjamin 2012-11-15 https://hdl.handle.net/10037/5516 eng eng Universitetet i Tromsø University of Tromsø https://hdl.handle.net/10037/5516 URN:NBN:no-uit_munin_5216 openAccess Copyright 2012 The Author(s) VDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497 VDP::Mathematics and natural science: 400::Zoology and botany: 480::Ecology: 488 VDP::Mathematics and natural science: 400::Mathematics: 410::Statistics: 412 VDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480::Marinbiologi: 497 VDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480::Økologi: 488 VDP::Matematikk og Naturvitenskap: 400::Matematikk: 410::Statistikk: 412 BIO-3910 Master thesis Mastergradsoppgave 2012 ftunivtroemsoe 2021-06-25T17:53:42Z 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. Master Thesis Arctic marine mammals Arctic Climate change harbour seal Phoca vitulina Svalbard University of Tromsø: Munin Open Research Archive Arctic Norway Svalbard |
institution |
Open Polar |
collection |
University of Tromsø: Munin Open Research Archive |
op_collection_id |
ftunivtroemsoe |
language |
English |
topic |
VDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497 VDP::Mathematics and natural science: 400::Zoology and botany: 480::Ecology: 488 VDP::Mathematics and natural science: 400::Mathematics: 410::Statistics: 412 VDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480::Marinbiologi: 497 VDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480::Økologi: 488 VDP::Matematikk og Naturvitenskap: 400::Matematikk: 410::Statistikk: 412 BIO-3910 |
spellingShingle |
VDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497 VDP::Mathematics and natural science: 400::Zoology and botany: 480::Ecology: 488 VDP::Mathematics and natural science: 400::Mathematics: 410::Statistics: 412 VDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480::Marinbiologi: 497 VDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480::Økologi: 488 VDP::Matematikk og Naturvitenskap: 400::Matematikk: 410::Statistikk: 412 BIO-3910 Merkel, Benjamin The world's northern most harbour seal population - How many are there? |
topic_facet |
VDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497 VDP::Mathematics and natural science: 400::Zoology and botany: 480::Ecology: 488 VDP::Mathematics and natural science: 400::Mathematics: 410::Statistics: 412 VDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480::Marinbiologi: 497 VDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480::Økologi: 488 VDP::Matematikk og Naturvitenskap: 400::Matematikk: 410::Statistikk: 412 BIO-3910 |
description |
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. |
format |
Master Thesis |
author |
Merkel, Benjamin |
author_facet |
Merkel, Benjamin |
author_sort |
Merkel, Benjamin |
title |
The world's northern most harbour seal population - How many are there? |
title_short |
The world's northern most harbour seal population - How many are there? |
title_full |
The world's northern most harbour seal population - How many are there? |
title_fullStr |
The world's northern most harbour seal population - How many are there? |
title_full_unstemmed |
The world's northern most harbour seal population - How many are there? |
title_sort |
world's northern most harbour seal population - how many are there? |
publisher |
Universitetet i Tromsø |
publishDate |
2012 |
url |
https://hdl.handle.net/10037/5516 |
geographic |
Arctic Norway Svalbard |
geographic_facet |
Arctic Norway Svalbard |
genre |
Arctic marine mammals Arctic Climate change harbour seal Phoca vitulina Svalbard |
genre_facet |
Arctic marine mammals Arctic Climate change harbour seal Phoca vitulina Svalbard |
op_relation |
https://hdl.handle.net/10037/5516 URN:NBN:no-uit_munin_5216 |
op_rights |
openAccess Copyright 2012 The Author(s) |
_version_ |
1766305237251915776 |