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Science 14 December 2007:
Vol. 318. no. 5857, pp. 1772 - 1775
DOI: 10.1126/science.1148744
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Reports

Declining Wild Salmon Populations in Relation to Parasites from Farm Salmon

Martin Krkosek,1,2{dagger} Jennifer S. Ford,3 Alexandra Morton,4 Subhash Lele,1 Ransom A. Myers,3* Mark A. Lewis1,2

Rather than benefiting wild fish, industrial aquaculture may contribute to declines in ocean fisheries and ecosystems. Farm salmon are commonly infected with salmon lice (Lepeophtheirus salmonis), which are native ectoparasitic copepods. We show that recurrent louse infestations of wild juvenile pink salmon (Oncorhynchus gorbuscha), all associated with salmon farms, have depressed wild pink salmon populations and placed them on a trajectory toward rapid local extinction. The louse-induced mortality of pink salmon is commonly over 80% and exceeds previous fishing mortality. If outbreaks continue, then local extinction is certain, and a 99% collapse in pink salmon population abundance is expected in four salmon generations. These results suggest that salmon farms can cause parasite outbreaks that erode the capacity of a coastal ecosystem to support wild salmon populations.

1 Centre for Mathematical Biology, Department of Mathematical and Statistical Sciences, University of Alberta, Edmonton, AB, Canada.
2 Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.
3 Biology Department, Dalhousie University, Halifax, NS, Canada.
4 Salmon Coast Field Station, Simoom Sound, BC, Canada.

* Deceased.

{dagger} To whom correspondence should be addressed. E-mail: mkrkosek{at}ualberta.ca

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THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
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Comment on "Declining Wild Salmon Populations in Relation to Parasites from Farm Salmon".
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Response to Comment on "Declining Wild Salmon Populations in Relation to Parasites from Farm Salmon".
M. Krkosek, J. S. Ford, A. Morton, S. Lele, and M. A. Lewis (2008)
Science 322, 1790c
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Colloquium Paper: Ecological extinction and evolution in the brave new ocean.
J. B. C. Jackson (2008)
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E-Letters:

Read all E-Letters

Opportunities to Improve Aquaculture and Wild Fisheries
Michael F. Tlusty
Science Online, 10 Jul 2008 [Full text]
Response to M. F. Tlusty's E-Letter
Martin Krkošek, et al.
Science Online, 27 Aug 2008 [Full text]

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