Document Detail


Causes and consequences of marine mammal population declines in southwest Alaska: a food-web perspective.
MedLine Citation:
PMID:  19451116     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Populations of sea otters, seals and sea lions have collapsed across much of southwest Alaska over the past several decades. The sea otter decline set off a trophic cascade in which the coastal marine ecosystem underwent a phase shift from kelp forests to deforested sea urchin barrens. This interaction in turn affected the distribution, abundance and productivity of numerous other species. Ecological consequences of the pinniped declines are largely unknown. Increased predation by transient (marine mammal-eating) killer whales probably caused the sea otter declines and may have caused the pinniped declines as well. Springer et al. proposed that killer whales, which purportedly fed extensively on great whales, expanded their diets to include a higher percentage of sea otters and pinnipeds following a sharp reduction in great whale numbers from post World War II industrial whaling. Critics of this hypothesis claim that great whales are not now and probably never were an important nutritional resource for killer whales. We used demographic/energetic analyses to evaluate whether or not a predator-prey system involving killer whales and the smaller marine mammals would be sustainable without some nutritional contribution from the great whales. Our results indicate that while such a system is possible, it could only exist under a narrow range of extreme conditions and is therefore highly unlikely.
Authors:
J A Estes; D F Doak; A M Springer; T M Williams
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Philosophical transactions of the Royal Society of London. Series B, Biological sciences     Volume:  364     ISSN:  1471-2970     ISO Abbreviation:  Philos. Trans. R. Soc. Lond., B, Biol. Sci.     Publication Date:  2009 Jun 
Date Detail:
Created Date:  2009-05-19     Completed Date:  2009-08-10     Revised Date:  2013-06-02    
Medline Journal Info:
Nlm Unique ID:  7503623     Medline TA:  Philos Trans R Soc Lond B Biol Sci     Country:  England    
Other Details:
Languages:  eng     Pagination:  1647-58     Citation Subset:  IM    
Affiliation:
Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA 95060, USA. jestes@ucsc.edu
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MeSH Terms
Descriptor/Qualifier:
Alaska
Animals
Ecosystem
Food Chain*
Mammals*
Marine Biology
Otters
Pacific Ocean
Population Dynamics
Sea Lions
Seals, Earless
Whale, Killer
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