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Dive behaviour and foraging effort of female cape fur seals Arctocephalus pusillus pusillus

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journal contribution
posted on 2019-01-01, 00:00 authored by S P Kirkman, D P Costa, A L Harrison, P G H Kotze, W H Oosthuizen, M Weise, J A Botha, John ArnouldJohn Arnould
© 2019 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited. While marine top predators can play a critical role in ecosystem structure and dynamics through their effects on prey populations, how the predators function in this role is often not well understood. In the Benguela region of southern Africa, the Cape fur seal (Arctocephalus pusillus pusillus) population constitutes the largest marine top predator biomass, but little is known of its foraging ecology other than its diet and some preliminary dive records. Dive information was obtained from 32 adult females instrumented with dive recorders at the Kleinsee colony (29°34.170 S, 16°59.800 E) in South Africa during 2006–2008. Most dives were in the depth range of epipelagic prey species (less than 50 m deep) and at night, reflecting the reliance of Cape fur seals on small, vertically migrating, schooling prey. However, most females also performed benthic dives, and benthic diving was prevalent in some individuals. Benthic diving was significantly associated with the frequency with which females exceeded their aerobic dive limit. The greater putative costs of benthic diving highlight the potential detrimental effects to Cape fur seals of well-documented changes in the availability of epipelagic prey species in the Benguela.

History

Journal

Royal Society Open Science

Volume

6

Issue

10

Article number

191369

Pagination

1 - 19

Publisher

The Royal Society

Location

London, Eng.

ISSN

2054-5703

eISSN

2054-5703

Language

eng

Publication classification

C1 Refereed article in a scholarly journal