Overlap and temporal variation in the diets of sympatric Antarctic and Subantarctic fur seals (Arctocephalus spp.) at Marion Island, Prince Edward Islands

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dc.contributor.author Reisinger, Ryan R.
dc.contributor.author Landman, Marietjie
dc.contributor.author Mgibantaka, Nonkoliso
dc.contributor.author Smale, Malcolm J.
dc.contributor.author Bester, Marthan Nieuwoudt
dc.contributor.author De Bruyn, P.J. Nico
dc.contributor.author Pistorius, Pierre A.
dc.date.accessioned 2018-06-12T07:33:19Z
dc.date.available 2018-06-12T07:33:19Z
dc.date.issued 2018-04-20
dc.description.abstract Antarctic (Arctocephalus gazella) and Subantarctic (A. tropicalis) fur seals are important predators in the Southern Ocean. Marion Island (southern Indian Ocean) hosts the largest sympatric breeding populations of these two species. Environmental and population changes here over two decades may have influenced their diet and trophic interactions. To quantify diet, we analysed prey remains in scat samples from Antarctic (661 scats) and Subantarctic (750 scats) fur seals collected at Marion Island (2006–2010). We assessed diet composition over time and calculated dietary overlap. The diet of both species was dominated by fish prey (98.2% and 99.4% of prey items), mainly myctophids. Antarctic fur seals consumed small numbers of penguins, cephalopods and crustaceans. In Subantarctic fur seal scats, crustaceans and cephalopods were rare and penguin remains were absent. The diets of the two species overlapped substantially (Pianka’s index = 0.98), however, small but significant differences in the relative proportions of prey were evident. Seasonal and annual diet changes suggest that their diet is similarly influenced by patterns of local prey availability and abundance. Despite substantial changes in the population size and trajectory of Antarctic and Subantarctic fur seals – which would be expected to influence trophic interactions between them – comparing our data to those from earlier studies (1989–2000) did not reveal significant long-term dietary changes in either species. en_ZA
dc.description.department Mammal Research Institute en_ZA
dc.description.department Zoology and Entomology en_ZA
dc.description.librarian am2018 en_ZA
dc.description.sponsorship The National Research Foundation (South Africa) under grant number SNA93071. RRR was supported by a National Research Foundation SANCOR post-doctoral fellowship (grant 94916). en_ZA
dc.description.uri http://www.tandfonline.com/loi/zpor20 en_ZA
dc.identifier.citation Ryan R. Reisinger, Marietjie Landman, Nonkoliso Mgibantaka, Malcolm J. Smale, Marthán N. Bester, P.J. Nico De Bruyn & Pierre A. Pistorius (2018) Overlap and temporal variation in the diets of sympatric Antarctic and Subantarctic fur seals (Arctocephalus spp.) at Marion Island, Prince Edward Islands, Polar Research, 37:1, 1451142, DOI: 10.1080/17518369.2018.1451142. en_ZA
dc.identifier.issn 0800-0395 (print)
dc.identifier.issn 1751-8369 (online)
dc.identifier.other 10.1080/17518369.2018.1451142
dc.identifier.uri http://hdl.handle.net/2263/65133
dc.language.iso en en_ZA
dc.publisher Co-Action Publishing en_ZA
dc.rights © 2018 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial License (http://creativecommons.org/licenses/by-nc/4.0/). en_ZA
dc.subject Prey en_ZA
dc.subject Scats en_ZA
dc.subject Foraging en_ZA
dc.subject Marine mammal en_ZA
dc.subject Pinniped en_ZA
dc.subject Confidence interval (CI) en_ZA
dc.subject Permutational multivariate analysis of variance (PERMANOVA) en_ZA
dc.subject Winter en_ZA
dc.subject Antarctic fur seal (Arctocephalus gazella) en_ZA
dc.subject Subantarctic fur seal (A. tropicalis) en_ZA
dc.subject Pup growth en_ZA
dc.subject Marion Island, Prince Edward Islands en_ZA
dc.subject Stable isotope en_ZA
dc.subject Seasonal changes en_ZA
dc.subject Foraging behavior en_ZA
dc.subject Population changes en_ZA
dc.subject Southern Ocean predator en_ZA
dc.title Overlap and temporal variation in the diets of sympatric Antarctic and Subantarctic fur seals (Arctocephalus spp.) at Marion Island, Prince Edward Islands en_ZA
dc.type Article en_ZA


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