Spatial and temporal distribution of Antarctic fur seals (Arctocephalus gazella) on the breeding grounds at Bird Island, South Georgia
The number of Antarctic fur seals (Arctocephalus gazella) in the area of the Scotia Sea has been increasing. Observation of their distribution on the breeding grounds are important to help design and interpret censuses. These seals are highly polygynous. In the study area at Bird Island, South Georg...
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ftnerc:oai:nora.nerc.ac.uk:520982 2023-05-15T13:49:35+02:00 Spatial and temporal distribution of Antarctic fur seals (Arctocephalus gazella) on the breeding grounds at Bird Island, South Georgia Boyd, I.L. 1989-12 http://nora.nerc.ac.uk/id/eprint/520982/ https://doi.org/10.1007/BF00238493 unknown Springer Boyd, I.L. 1989 Spatial and temporal distribution of Antarctic fur seals (Arctocephalus gazella) on the breeding grounds at Bird Island, South Georgia. Polar Biology, 10 (3). 179-185. https://doi.org/10.1007/BF00238493 <https://doi.org/10.1007/BF00238493> Publication - Article PeerReviewed 1989 ftnerc https://doi.org/10.1007/BF00238493 2023-02-04T19:47:06Z The number of Antarctic fur seals (Arctocephalus gazella) in the area of the Scotia Sea has been increasing. Observation of their distribution on the breeding grounds are important to help design and interpret censuses. These seals are highly polygynous. In the study area at Bird Island, South Georgia, females give birth and are mated in densely packed colonies located along the shore close to the tideline. Males establish territories in this area, but are also found further inland. This study examined the density-dependent processes regulating the instantaneous size of the male breeding population; the distribution of males in relation to space and the number of females available to be mated and the effect of gregarious behaviour of females on male dispersion. Males were only territorial on the beaches in the areas where most females gave birth and subsequently had their post-partum oestrus. There was an apparent lower (19–20 m2) and upper (40 m2) limit to territory size. Males were excluded from the beach areas when the average density on the beaches was greater than 5 males per 200 m2. An asymptotic density of 10–11 males per 200 m2 was reached on the beaches and 4–5 males per 200 m2 elsewhere. These two asymptotic densities may represent the upper and lower limits of density for a territorial system of dispersion. A model of the temporal changes in female numbers suggested that the total number of females occupying an area of beach during the mating period was approximately twice the number at the peak of the season. There was no indication that males compensated for low female density by increasing territory size. Females and pups became more dispersed after the end of the mating period. It is suggested that one function of gregariousness in females is as a mechanism for mate selection. This study also has implications for methods used to measure population size. Article in Journal/Newspaper Antarc* Antarctic Antarctic Fur Seals Arctocephalus gazella Bird Island Polar Biology Scotia Sea Natural Environment Research Council: NERC Open Research Archive Antarctic Scotia Sea Bird Island ENVELOPE(-38.060,-38.060,-54.004,-54.004) The Beaches ENVELOPE(-56.832,-56.832,49.583,49.583) Polar Biology 10 3 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
unknown |
description |
The number of Antarctic fur seals (Arctocephalus gazella) in the area of the Scotia Sea has been increasing. Observation of their distribution on the breeding grounds are important to help design and interpret censuses. These seals are highly polygynous. In the study area at Bird Island, South Georgia, females give birth and are mated in densely packed colonies located along the shore close to the tideline. Males establish territories in this area, but are also found further inland. This study examined the density-dependent processes regulating the instantaneous size of the male breeding population; the distribution of males in relation to space and the number of females available to be mated and the effect of gregarious behaviour of females on male dispersion. Males were only territorial on the beaches in the areas where most females gave birth and subsequently had their post-partum oestrus. There was an apparent lower (19–20 m2) and upper (40 m2) limit to territory size. Males were excluded from the beach areas when the average density on the beaches was greater than 5 males per 200 m2. An asymptotic density of 10–11 males per 200 m2 was reached on the beaches and 4–5 males per 200 m2 elsewhere. These two asymptotic densities may represent the upper and lower limits of density for a territorial system of dispersion. A model of the temporal changes in female numbers suggested that the total number of females occupying an area of beach during the mating period was approximately twice the number at the peak of the season. There was no indication that males compensated for low female density by increasing territory size. Females and pups became more dispersed after the end of the mating period. It is suggested that one function of gregariousness in females is as a mechanism for mate selection. This study also has implications for methods used to measure population size. |
format |
Article in Journal/Newspaper |
author |
Boyd, I.L. |
spellingShingle |
Boyd, I.L. Spatial and temporal distribution of Antarctic fur seals (Arctocephalus gazella) on the breeding grounds at Bird Island, South Georgia |
author_facet |
Boyd, I.L. |
author_sort |
Boyd, I.L. |
title |
Spatial and temporal distribution of Antarctic fur seals (Arctocephalus gazella) on the breeding grounds at Bird Island, South Georgia |
title_short |
Spatial and temporal distribution of Antarctic fur seals (Arctocephalus gazella) on the breeding grounds at Bird Island, South Georgia |
title_full |
Spatial and temporal distribution of Antarctic fur seals (Arctocephalus gazella) on the breeding grounds at Bird Island, South Georgia |
title_fullStr |
Spatial and temporal distribution of Antarctic fur seals (Arctocephalus gazella) on the breeding grounds at Bird Island, South Georgia |
title_full_unstemmed |
Spatial and temporal distribution of Antarctic fur seals (Arctocephalus gazella) on the breeding grounds at Bird Island, South Georgia |
title_sort |
spatial and temporal distribution of antarctic fur seals (arctocephalus gazella) on the breeding grounds at bird island, south georgia |
publisher |
Springer |
publishDate |
1989 |
url |
http://nora.nerc.ac.uk/id/eprint/520982/ https://doi.org/10.1007/BF00238493 |
long_lat |
ENVELOPE(-38.060,-38.060,-54.004,-54.004) ENVELOPE(-56.832,-56.832,49.583,49.583) |
geographic |
Antarctic Scotia Sea Bird Island The Beaches |
geographic_facet |
Antarctic Scotia Sea Bird Island The Beaches |
genre |
Antarc* Antarctic Antarctic Fur Seals Arctocephalus gazella Bird Island Polar Biology Scotia Sea |
genre_facet |
Antarc* Antarctic Antarctic Fur Seals Arctocephalus gazella Bird Island Polar Biology Scotia Sea |
op_relation |
Boyd, I.L. 1989 Spatial and temporal distribution of Antarctic fur seals (Arctocephalus gazella) on the breeding grounds at Bird Island, South Georgia. Polar Biology, 10 (3). 179-185. https://doi.org/10.1007/BF00238493 <https://doi.org/10.1007/BF00238493> |
op_doi |
https://doi.org/10.1007/BF00238493 |
container_title |
Polar Biology |
container_volume |
10 |
container_issue |
3 |
_version_ |
1766251811328491520 |