Age distribution of breeding female Antarctic fur seals in relation to changes in population growth rate
The age distribution of breeding female Arctocephalus gazella at Bird Island, South Georgia, in 1988 was compared with the age distribution of a sample obtained in 1971-1973. The mean age in 1971-1973 was 7.41 (SE 0.26) yr and in 1988 it was 6.93 (SE 0.20) yr. After correction for age-dependent arri...
Published in: | Canadian Journal of Zoology |
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Main Authors: | , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
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1990
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Online Access: | https://research-portal.st-andrews.ac.uk/en/researchoutput/age-distribution-of-breeding-female-antarctic-fur-seals-in-relation-to-changes-in-population-growth-rate(7d53b887-4e5b-4316-b7f2-ff1b5f8715cb).html https://doi.org/10.1139/z90-307 http://www.scopus.com/inward/record.url?scp=0025684428&partnerID=8YFLogxK |
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ftunstandrewcris:oai:research-portal.st-andrews.ac.uk:publications/7d53b887-4e5b-4316-b7f2-ff1b5f8715cb 2024-09-09T19:04:40+00:00 Age distribution of breeding female Antarctic fur seals in relation to changes in population growth rate Boyd, I. L. Lunn, N. J. Rothery, P. Croxall, J. P. 1990 https://research-portal.st-andrews.ac.uk/en/researchoutput/age-distribution-of-breeding-female-antarctic-fur-seals-in-relation-to-changes-in-population-growth-rate(7d53b887-4e5b-4316-b7f2-ff1b5f8715cb).html https://doi.org/10.1139/z90-307 http://www.scopus.com/inward/record.url?scp=0025684428&partnerID=8YFLogxK eng eng https://research-portal.st-andrews.ac.uk/en/researchoutput/age-distribution-of-breeding-female-antarctic-fur-seals-in-relation-to-changes-in-population-growth-rate(7d53b887-4e5b-4316-b7f2-ff1b5f8715cb).html info:eu-repo/semantics/restrictedAccess Boyd , I L , Lunn , N J , Rothery , P & Croxall , J P 1990 , ' Age distribution of breeding female Antarctic fur seals in relation to changes in population growth rate ' , Canadian Journal of Zoology , vol. 68 , no. 10 , pp. 2209-2213 . https://doi.org/10.1139/z90-307 article 1990 ftunstandrewcris https://doi.org/10.1139/z90-307 2024-06-19T23:59:57Z The age distribution of breeding female Arctocephalus gazella at Bird Island, South Georgia, in 1988 was compared with the age distribution of a sample obtained in 1971-1973. The mean age in 1971-1973 was 7.41 (SE 0.26) yr and in 1988 it was 6.93 (SE 0.20) yr. After correction for age-dependent arrival time at the pupping beach in 1988, the mean age was 6.22 (SE 0.14) yr, which was significantly lower than in 1971-1973. Indicators of population size suggested that population growth at Bird Island had declined to <3% annually by 1988 compared with rapid growth (17%) in 1958-1972. Exponential models fitted to the frequency distribution of age-classes >5 yr and corrected for the rate of increase of the population gave adult survival rates of 0.66 (SE 0.03) and 0.88 (SE 0.02) for the 1988 and 1971-1973 samples, respectively. The reduced apparent adult survival rate in the 1988 sample was probably caused by emigration brought about by high densities of females on the pupping beaches. There are few signs that the fur seal population at South Georgia is close to carrying capacity. -Authors Article in Journal/Newspaper Antarc* Antarctic Antarctic Fur Seals Arctocephalus gazella Bird Island University of St Andrews: Research Portal Antarctic Bird Island ENVELOPE(-38.060,-38.060,-54.004,-54.004) Canadian Journal of Zoology 68 10 2209 2213 |
institution |
Open Polar |
collection |
University of St Andrews: Research Portal |
op_collection_id |
ftunstandrewcris |
language |
English |
description |
The age distribution of breeding female Arctocephalus gazella at Bird Island, South Georgia, in 1988 was compared with the age distribution of a sample obtained in 1971-1973. The mean age in 1971-1973 was 7.41 (SE 0.26) yr and in 1988 it was 6.93 (SE 0.20) yr. After correction for age-dependent arrival time at the pupping beach in 1988, the mean age was 6.22 (SE 0.14) yr, which was significantly lower than in 1971-1973. Indicators of population size suggested that population growth at Bird Island had declined to <3% annually by 1988 compared with rapid growth (17%) in 1958-1972. Exponential models fitted to the frequency distribution of age-classes >5 yr and corrected for the rate of increase of the population gave adult survival rates of 0.66 (SE 0.03) and 0.88 (SE 0.02) for the 1988 and 1971-1973 samples, respectively. The reduced apparent adult survival rate in the 1988 sample was probably caused by emigration brought about by high densities of females on the pupping beaches. There are few signs that the fur seal population at South Georgia is close to carrying capacity. -Authors |
format |
Article in Journal/Newspaper |
author |
Boyd, I. L. Lunn, N. J. Rothery, P. Croxall, J. P. |
spellingShingle |
Boyd, I. L. Lunn, N. J. Rothery, P. Croxall, J. P. Age distribution of breeding female Antarctic fur seals in relation to changes in population growth rate |
author_facet |
Boyd, I. L. Lunn, N. J. Rothery, P. Croxall, J. P. |
author_sort |
Boyd, I. L. |
title |
Age distribution of breeding female Antarctic fur seals in relation to changes in population growth rate |
title_short |
Age distribution of breeding female Antarctic fur seals in relation to changes in population growth rate |
title_full |
Age distribution of breeding female Antarctic fur seals in relation to changes in population growth rate |
title_fullStr |
Age distribution of breeding female Antarctic fur seals in relation to changes in population growth rate |
title_full_unstemmed |
Age distribution of breeding female Antarctic fur seals in relation to changes in population growth rate |
title_sort |
age distribution of breeding female antarctic fur seals in relation to changes in population growth rate |
publishDate |
1990 |
url |
https://research-portal.st-andrews.ac.uk/en/researchoutput/age-distribution-of-breeding-female-antarctic-fur-seals-in-relation-to-changes-in-population-growth-rate(7d53b887-4e5b-4316-b7f2-ff1b5f8715cb).html https://doi.org/10.1139/z90-307 http://www.scopus.com/inward/record.url?scp=0025684428&partnerID=8YFLogxK |
long_lat |
ENVELOPE(-38.060,-38.060,-54.004,-54.004) |
geographic |
Antarctic Bird Island |
geographic_facet |
Antarctic Bird Island |
genre |
Antarc* Antarctic Antarctic Fur Seals Arctocephalus gazella Bird Island |
genre_facet |
Antarc* Antarctic Antarctic Fur Seals Arctocephalus gazella Bird Island |
op_source |
Boyd , I L , Lunn , N J , Rothery , P & Croxall , J P 1990 , ' Age distribution of breeding female Antarctic fur seals in relation to changes in population growth rate ' , Canadian Journal of Zoology , vol. 68 , no. 10 , pp. 2209-2213 . https://doi.org/10.1139/z90-307 |
op_relation |
https://research-portal.st-andrews.ac.uk/en/researchoutput/age-distribution-of-breeding-female-antarctic-fur-seals-in-relation-to-changes-in-population-growth-rate(7d53b887-4e5b-4316-b7f2-ff1b5f8715cb).html |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1139/z90-307 |
container_title |
Canadian Journal of Zoology |
container_volume |
68 |
container_issue |
10 |
container_start_page |
2209 |
op_container_end_page |
2213 |
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1809818693351243776 |