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Inter-site movements and associations of southern elephant seals (Mirounga leonina) ashore at Marion Island
Dissertation (MSc (Zoology))--University of Pretoria, 2018.
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| Format: | Thesis |
| Language: | English |
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2026
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| _version_ | 1867613517749682176 |
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| access_status_str | Open Access |
| author2 | Bester, Marthán N. |
| author_browse | Bester, Marthán N. |
| author_facet | Bester, Marthán N. |
| collection | Thesis |
| description | Dissertation (MSc (Zoology))--University of Pretoria, 2018. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/110191 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:37:24.815Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/110191 Inter-site movements and associations of southern elephant seals (Mirounga leonina) ashore at Marion Island Bester, Marthán N. eclaireza@gmail.com De Bruyn, P. J. Nico Church, Erin Claire Southern elephant seal Marion Island inter-site movement haul-out social association physiology behaviour environmental factors site fidelity Dissertation (MSc (Zoology))--University of Pretoria, 2018. Southern elephant seals (Mirounga leonina) periodically haul out on Marion Island during the year to moult, breed, or to rest. During a haul-out period, elephant seals generally remain ashore until they have finished moulting, breeding or resting, although movement between beaches on the island during a haul-out may occur. Simple descriptive analyses of the available longitudinal mark- iv resighting data gathered on this population between 1983 and 2013 showed that a proportion of the southern elephant seal population at Marion Island change haul-out location within the haulout periods. Through further multiple logistic regression analyses, these movements were found to be influenced by several demographic factors, including sex, age, and breeding status, as well as behavioural factors, such as haul-out period, and environmental factors, such as haul-out location. Within the four different haul-out periods included in this study (the natal, moulting, breeding and winter haul-outs) male elephant seals moved haul-out location significantly more than females, and younger elephant seals move significantly more than older individuals. The moulting season haulout had the greatest proportion of haul-out location changes within a season and the breeding season the smallest. Several beaches showed higher proportions of seal influx than other beaches, revealing a definite beach preference by elephant seals at Marion Island. During haul-out periods, elephant seals form aggregations, and associations between individuals were investigated as explanatory variables of the observed inter-site movements. Multiple regression quadratic assignment procedure (MRQAP) and generalized affiliation index (GAI) indicated that the inherent gregariousness of the species, as well as age, were the most powerful variables to predict whether seals showed any degree of preferred or avoided association within the population. When controlling for all presumed confounding factors, there was significant evidence for long-term preferred or avoided association between individuals across the 31 years of this study. However, there was little indication that these associations would affect inter-site movement dynamics. Intersite movements could possibly be due to many different factors, including a type of avoidance behaviour in females due to harassment from secondary males, or inbreeding avoidance of southern elephant seals at Marion Island. Zoology and Entomology MSc (Zoology) 2026-05-15T17:26:37Z 2026-05-15T17:26:37Z 18/12/18 2018 Dissertation http://hdl.handle.net/2263/110191 en application/pdf |
| spellingShingle | Southern elephant seal Marion Island inter-site movement haul-out social association physiology behaviour environmental factors site fidelity Inter-site movements and associations of southern elephant seals (Mirounga leonina) ashore at Marion Island |
| title | Inter-site movements and associations of southern elephant seals (Mirounga leonina) ashore at Marion Island |
| title_full | Inter-site movements and associations of southern elephant seals (Mirounga leonina) ashore at Marion Island |
| title_fullStr | Inter-site movements and associations of southern elephant seals (Mirounga leonina) ashore at Marion Island |
| title_full_unstemmed | Inter-site movements and associations of southern elephant seals (Mirounga leonina) ashore at Marion Island |
| title_short | Inter-site movements and associations of southern elephant seals (Mirounga leonina) ashore at Marion Island |
| title_sort | inter site movements and associations of southern elephant seals mirounga leonina ashore at marion island |
| topic | Southern elephant seal Marion Island inter-site movement haul-out social association physiology behaviour environmental factors site fidelity |
| url | http://hdl.handle.net/2263/110191 |