Maternal foraging behaviour of Subantarctic fur seals from Marion Island
Foraging forms the cornerstone of an animal’s life-history. An individual's foraging success shapes the demography and health of a population. Understanding key facets of maternal foraging behaviour are crucial to get a holistic picture of both regional and local environmental factors that driv...
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ftunivpretoria:oai:repository.up.ac.za:2263/37354 2023-05-15T13:22:34+02:00 Maternal foraging behaviour of Subantarctic fur seals from Marion Island Wege, Mia Bester, Marthan Nieuwoudt De Bruyn, P.J. Nico 2013-09-06 http://hdl.handle.net/2263/37354 en eng University of Pretoria http://hdl.handle.net/2263/37354 Wege, M 2013, Maternal foraging behaviour of Subantarctic fur seals from Marion Island, Africa, MSc dissertation, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/37354> E13/9/1050/gm © 2013 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. Maternal foraging Foraging behaviour Marine top predator Arctocephalus tropicalis females Species Myctophid prey Subantarctic fur seals UCTD Dissertation 2013 ftunivpretoria 2022-05-31T13:24:20Z Foraging forms the cornerstone of an animal’s life-history. An individual's foraging success shapes the demography and health of a population. Understanding key facets of maternal foraging behaviour are crucial to get a holistic picture of both regional and local environmental factors that drive foraging behaviour. This study aimed to measure the maternal foraging behaviour of a marine top predator, the Subantarctic fur seal (Arctocephalus tropicalis), from Marion Island (MI) over a range of spatial and temporal scales. Arctocephalus tropicalis females from MI have one of the longest duration foraging trips for the species. They are most similar to conspecifics at temperate Amsterdam Island, but differ considerably from those at subantarctic Îles Crozet and Macquarie Island. Hitherto, no diving data existed for MI females. I illustrate how their diving behaviour is more similar to individuals from Îles Crozet despite their differences in foraging trip parameters. Together with Îles Crozet, MI females have one of the deepest mean diving depths (34.5 ± 2.2 m , 45.2 ± 4.8 m summer and winter respectively) and longest dive durations (70.2 ± 3 s , 104.3 ± 7.8 s summer and winter respectively) for the species. In summer, females follow the diel vertical migration of their myctophid prey. Counter intuitively, during the winter, females performed short and shallow crepuscular dives, possibly foraging on different prey. Considering that these individuals dive in deep waters, this is most likely related to myctophids occupying lower depths in the water column during winter. At dusk and dawn they are inaccessible to diving fur seals. At-sea data from multiple foraging trips per female illustrated that females have both a colony- and individual preferred foraging direction which varied seasonally. Individuals travelled consistently in the same direction regionally, but locally appear to track prey in a heterogeneous environment. The few trips in the winter to the west of MI suggest that this is a short-term response to ... Doctoral or Postdoctoral Thesis Amsterdam Island Îles Crozet Macquarie Island Marion Island University of Pretoria: UPSpace |
institution |
Open Polar |
collection |
University of Pretoria: UPSpace |
op_collection_id |
ftunivpretoria |
language |
English |
topic |
Maternal foraging Foraging behaviour Marine top predator Arctocephalus tropicalis females Species Myctophid prey Subantarctic fur seals UCTD |
spellingShingle |
Maternal foraging Foraging behaviour Marine top predator Arctocephalus tropicalis females Species Myctophid prey Subantarctic fur seals UCTD Wege, Mia Maternal foraging behaviour of Subantarctic fur seals from Marion Island |
topic_facet |
Maternal foraging Foraging behaviour Marine top predator Arctocephalus tropicalis females Species Myctophid prey Subantarctic fur seals UCTD |
description |
Foraging forms the cornerstone of an animal’s life-history. An individual's foraging success shapes the demography and health of a population. Understanding key facets of maternal foraging behaviour are crucial to get a holistic picture of both regional and local environmental factors that drive foraging behaviour. This study aimed to measure the maternal foraging behaviour of a marine top predator, the Subantarctic fur seal (Arctocephalus tropicalis), from Marion Island (MI) over a range of spatial and temporal scales. Arctocephalus tropicalis females from MI have one of the longest duration foraging trips for the species. They are most similar to conspecifics at temperate Amsterdam Island, but differ considerably from those at subantarctic Îles Crozet and Macquarie Island. Hitherto, no diving data existed for MI females. I illustrate how their diving behaviour is more similar to individuals from Îles Crozet despite their differences in foraging trip parameters. Together with Îles Crozet, MI females have one of the deepest mean diving depths (34.5 ± 2.2 m , 45.2 ± 4.8 m summer and winter respectively) and longest dive durations (70.2 ± 3 s , 104.3 ± 7.8 s summer and winter respectively) for the species. In summer, females follow the diel vertical migration of their myctophid prey. Counter intuitively, during the winter, females performed short and shallow crepuscular dives, possibly foraging on different prey. Considering that these individuals dive in deep waters, this is most likely related to myctophids occupying lower depths in the water column during winter. At dusk and dawn they are inaccessible to diving fur seals. At-sea data from multiple foraging trips per female illustrated that females have both a colony- and individual preferred foraging direction which varied seasonally. Individuals travelled consistently in the same direction regionally, but locally appear to track prey in a heterogeneous environment. The few trips in the winter to the west of MI suggest that this is a short-term response to ... |
author2 |
Bester, Marthan Nieuwoudt De Bruyn, P.J. Nico |
format |
Doctoral or Postdoctoral Thesis |
author |
Wege, Mia |
author_facet |
Wege, Mia |
author_sort |
Wege, Mia |
title |
Maternal foraging behaviour of Subantarctic fur seals from Marion Island |
title_short |
Maternal foraging behaviour of Subantarctic fur seals from Marion Island |
title_full |
Maternal foraging behaviour of Subantarctic fur seals from Marion Island |
title_fullStr |
Maternal foraging behaviour of Subantarctic fur seals from Marion Island |
title_full_unstemmed |
Maternal foraging behaviour of Subantarctic fur seals from Marion Island |
title_sort |
maternal foraging behaviour of subantarctic fur seals from marion island |
publisher |
University of Pretoria |
publishDate |
2013 |
url |
http://hdl.handle.net/2263/37354 |
genre |
Amsterdam Island Îles Crozet Macquarie Island Marion Island |
genre_facet |
Amsterdam Island Îles Crozet Macquarie Island Marion Island |
op_relation |
http://hdl.handle.net/2263/37354 Wege, M 2013, Maternal foraging behaviour of Subantarctic fur seals from Marion Island, Africa, MSc dissertation, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/37354> E13/9/1050/gm |
op_rights |
© 2013 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
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1766365541786714112 |