Title: COMPETITION AMONG PENGUINS AND CETACEANS REVEALS TROPHIC CASCADES IN THE WESTERN ROSS SEA, ANTARCTICA
Abstract: EcologyVolume 87, Issue 8 p. 2080-2093 Article COMPETITION AMONG PENGUINS AND CETACEANS REVEALS TROPHIC CASCADES IN THE WESTERN ROSS SEA, ANTARCTICA David G. Ainley, David G. Ainley H. T. Harvey and Associates, 3150 Almaden Expressway, Suite 145, San Jose, California 95118 USA E-mail: [email protected] for more papers by this authorGrant Ballard, Grant Ballard PRBO Conservation Science, P.O. Box 1157, Bolinas, California 94924 USA, and Ecology, Evolution and Behaviour, School of Biological Sciences, University of Auckland, New ZealandSearch for more papers by this authorKatie M. Dugger, Katie M. Dugger Department of Fisheries and Wildlife, Oregon State University, 104 Nash Hall, Corvallis, Oregon 97331 USASearch for more papers by this author David G. Ainley, David G. Ainley H. T. Harvey and Associates, 3150 Almaden Expressway, Suite 145, San Jose, California 95118 USA E-mail: [email protected] for more papers by this authorGrant Ballard, Grant Ballard PRBO Conservation Science, P.O. Box 1157, Bolinas, California 94924 USA, and Ecology, Evolution and Behaviour, School of Biological Sciences, University of Auckland, New ZealandSearch for more papers by this authorKatie M. Dugger, Katie M. Dugger Department of Fisheries and Wildlife, Oregon State University, 104 Nash Hall, Corvallis, Oregon 97331 USASearch for more papers by this author First published: 01 August 2006 https://doi.org/10.1890/0012-9658(2006)87[2080:CAPACR]2.0.CO;2Citations: 106 〈http://rapidfire.sci.gsfc.nasa.gov/subsets/?RossSea〉 Corresponding Editor: S. P. Lawler. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Abstract An apparent trophic cascade that appears during summer in the western Ross Sea, Antarctica, explains why the Antarctic silverfish (Pleuragramma antarcticum) there becomes cannibalistic; its principal prey, crystal krill (Euphausia crystallorophias) becomes scarce; and the diatom community is minimally grazed compared to adjacent areas. The krill is the major grazer of diatoms. On the basis of fieldwork at Ross Island, we suggest that the cascade results from foraging by unusually numerous Adélie Penguins (Pygoscelis adeliae), minke whales (Balaenoptera bonaerensis), and fish-eating killer whales (Orcinus orca). These species and other top predators apparently deplete the krill and silverfish. In drawing our conclusions, we were aided by two “natural experiments.” In one “experiment,” large, grounded icebergs altered the seasonal pattern of change in regional sea-ice cover, but not the seasonal change in penguin diet and foraging behavior that was also detected during the pre-iceberg era. In the other “experiment,” a short-term polynya (opening in the ice) brought penguins and whales together in a confined area, this time altering both penguin diet and foraging behavior. We conclude that the foraging of penguins and whales, and not a formerly hypothesized seasonal decrease in sea-ice cover, explains (1) the annual switch in the penguins' prey from krill to silverfish, (2) the subsequent lengthening of penguin foraging trips, and (3) a marked decline of cetaceans in the area later in the season. Reduction in the middle-trophic-level prey is expressed in the relaxed grazing pressure on phytoplankton. Citing Literature Volume87, Issue8August 2006Pages 2080-2093 RelatedInformation
Publication Year: 2006
Publication Date: 2006-08-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
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Cited By Count: 149
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