Cephalopod diet of the Cape fur seal, Arctocephalus pusillus pusillus, along the Namibian coast: variation due to location
Scats of the Cape fur seal, Arctocephalus pusillus pusillus, were sampled at four mainland colonies, Cape Cross, Atlas Bay,Wolf Bay and Van Reenen Bay, along the Namibian coast over a period of eight years (1994–2001) to assess the diversity and spatial variability in the cephalopod component of the...
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ftjafricanj:oai:ojs.ajol.info:article/153244 2023-05-15T18:03:11+02:00 Cephalopod diet of the Cape fur seal, Arctocephalus pusillus pusillus, along the Namibian coast: variation due to location de Bruyn, P.J.N. Bester, M.N. Kirkman, S.P. Mecenero, S Roux, J.P. Klages, N.T.W. 2017-03-15 application/pdf http://www.ajol.info/index.php/az/article/view/153244 eng eng NISC (Pty) Ltd http://www.ajol.info/index.php/az/article/view/153244/142835 http://www.ajol.info/index.php/az/article/view/153244 The copyright belongs to the Zoological Society of Southern Africa. African Zoology; Vol 40, No 2 (2005); 261-270 2224-073X 1562-7020 Arctocephalus pusillus pusillus cephalopods spatial variation diet scat samples Namibia info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Peer-reviewed Article 2017 ftjafricanj 2017-03-19T01:02:22Z Scats of the Cape fur seal, Arctocephalus pusillus pusillus, were sampled at four mainland colonies, Cape Cross, Atlas Bay,Wolf Bay and Van Reenen Bay, along the Namibian coast over a period of eight years (1994–2001) to assess the diversity and spatial variability in the cephalopod component of the seal diet. Additional scat samples were collected from the Possession Island seal colony (1999–2000) to gain a broader perspective of spatial variation. A uniform and low diversity of cephalopods, only six species amongst all colonies, was identified, indicating that independently the scat sampling method is unsatisfactory for determining species diversity within the diet. Given the ease of scat collection, this method does, however, provide valuable insight into the variability of the most important species in the diet. Ommastrephids dominated the cephalopod component of the diet of seals from Atlas/Wolf Bay and Cape Cross, both in terms of wet mass and numbers. Sepia australis proved to be numerically the most important cephalopod in the diet of seals from Possession Island and Van Reenen Bay, while Octopus magnificus dominated at these colonies in terms of wet mass. Contrary to previous findings it is suggested that seals from Van Reenen Bay and Possession Island forage south of the upwelling cell at Lüderitz (in the southern Benguela ecosystem), while previous evidence of Atlas/Wolf Bay and Cape Cross seals foraging north of this upwelling cell (in the northern Benguela ecosystem) is supported. Prey specimen size differences, within species between colonies, were identified, but lack of cephalopod life history and movement data, and scat sampling biases preclude adequate explanation of these findings, indicating the necessity for further studies.Keywords: Arctocephalus pusillus pusillus, cephalopods, spatial variation, diet, scat samples, Namibia Article in Journal/Newspaper Possession Island AJOL - African Journals Online Possession Island ENVELOPE(171.200,171.200,-71.867,-71.867) |
institution |
Open Polar |
collection |
AJOL - African Journals Online |
op_collection_id |
ftjafricanj |
language |
English |
topic |
Arctocephalus pusillus pusillus cephalopods spatial variation diet scat samples Namibia |
spellingShingle |
Arctocephalus pusillus pusillus cephalopods spatial variation diet scat samples Namibia de Bruyn, P.J.N. Bester, M.N. Kirkman, S.P. Mecenero, S Roux, J.P. Klages, N.T.W. Cephalopod diet of the Cape fur seal, Arctocephalus pusillus pusillus, along the Namibian coast: variation due to location |
topic_facet |
Arctocephalus pusillus pusillus cephalopods spatial variation diet scat samples Namibia |
description |
Scats of the Cape fur seal, Arctocephalus pusillus pusillus, were sampled at four mainland colonies, Cape Cross, Atlas Bay,Wolf Bay and Van Reenen Bay, along the Namibian coast over a period of eight years (1994–2001) to assess the diversity and spatial variability in the cephalopod component of the seal diet. Additional scat samples were collected from the Possession Island seal colony (1999–2000) to gain a broader perspective of spatial variation. A uniform and low diversity of cephalopods, only six species amongst all colonies, was identified, indicating that independently the scat sampling method is unsatisfactory for determining species diversity within the diet. Given the ease of scat collection, this method does, however, provide valuable insight into the variability of the most important species in the diet. Ommastrephids dominated the cephalopod component of the diet of seals from Atlas/Wolf Bay and Cape Cross, both in terms of wet mass and numbers. Sepia australis proved to be numerically the most important cephalopod in the diet of seals from Possession Island and Van Reenen Bay, while Octopus magnificus dominated at these colonies in terms of wet mass. Contrary to previous findings it is suggested that seals from Van Reenen Bay and Possession Island forage south of the upwelling cell at Lüderitz (in the southern Benguela ecosystem), while previous evidence of Atlas/Wolf Bay and Cape Cross seals foraging north of this upwelling cell (in the northern Benguela ecosystem) is supported. Prey specimen size differences, within species between colonies, were identified, but lack of cephalopod life history and movement data, and scat sampling biases preclude adequate explanation of these findings, indicating the necessity for further studies.Keywords: Arctocephalus pusillus pusillus, cephalopods, spatial variation, diet, scat samples, Namibia |
format |
Article in Journal/Newspaper |
author |
de Bruyn, P.J.N. Bester, M.N. Kirkman, S.P. Mecenero, S Roux, J.P. Klages, N.T.W. |
author_facet |
de Bruyn, P.J.N. Bester, M.N. Kirkman, S.P. Mecenero, S Roux, J.P. Klages, N.T.W. |
author_sort |
de Bruyn, P.J.N. |
title |
Cephalopod diet of the Cape fur seal, Arctocephalus pusillus pusillus, along the Namibian coast: variation due to location |
title_short |
Cephalopod diet of the Cape fur seal, Arctocephalus pusillus pusillus, along the Namibian coast: variation due to location |
title_full |
Cephalopod diet of the Cape fur seal, Arctocephalus pusillus pusillus, along the Namibian coast: variation due to location |
title_fullStr |
Cephalopod diet of the Cape fur seal, Arctocephalus pusillus pusillus, along the Namibian coast: variation due to location |
title_full_unstemmed |
Cephalopod diet of the Cape fur seal, Arctocephalus pusillus pusillus, along the Namibian coast: variation due to location |
title_sort |
cephalopod diet of the cape fur seal, arctocephalus pusillus pusillus, along the namibian coast: variation due to location |
publisher |
NISC (Pty) Ltd |
publishDate |
2017 |
url |
http://www.ajol.info/index.php/az/article/view/153244 |
long_lat |
ENVELOPE(171.200,171.200,-71.867,-71.867) |
geographic |
Possession Island |
geographic_facet |
Possession Island |
genre |
Possession Island |
genre_facet |
Possession Island |
op_source |
African Zoology; Vol 40, No 2 (2005); 261-270 2224-073X 1562-7020 |
op_relation |
http://www.ajol.info/index.php/az/article/view/153244/142835 http://www.ajol.info/index.php/az/article/view/153244 |
op_rights |
The copyright belongs to the Zoological Society of Southern Africa. |
_version_ |
1766173915194851328 |