Eg on lower saskatchewan river as sturgeon stocks

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Unformatted text preview: ial harvesters switched to more abundant species. 25000 A 20000 15000 10000 5000 0 75 80 85 90 95 M7.33 BIO 3115 Université d’Ottawa / University of Ottawa 2012 Shifting pressure on other groundfish species in the Gulf of St. Lawrence • • In response to dramatic declines in harvest of other groundfish, focus shifted in middle 1980s to yellowtail In an effort to protect stock, yellowtail quotas first introduced in 1998. M7.34 BIO 3115 Université d’Ottawa / University of Ottawa 2012 M7.17 BIO 3115 Conservation Biology Consequences of exploitation V: ecosystem effects Reduced abundances of “keystone” species as a result of exploitation can result in dramatic changes within communities as well as in ecological processes. E.g. reduction in beaver populations from trapping can (and indeed have) lead to dramatic changes in forest community structure. M7.35 BIO 3115 Université d’Ottawa / University of Ottawa 2012 Ecosystemic effects of overexploitation: Sea otters in the Aleutians Sea Otter Predation Herbivory Sea Urchin M7.36 BIO 3115 Université d’Ottawa / University of Ottawa 2012 M7.18 BIO 3115...
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This document was uploaded on 03/11/2014 for the course BIO 3115 at University of Ottawa.

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