29 bio 3115 universit dottawa university of ottawa

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Unformatted text preview: in age-structure of Gulf cod under commercial exploitation Abundance of age classes (millions) M7.30 BIO 3115 Université d’Ottawa / University of Ottawa 2012 M7.15 BIO 3115 Conservation Biology Consequences of exploitation III: changes in spatial distribution Exploitation can result in changes in the spatial distribution, forcing populations to leave areas of optimal habitat for areas of marginal habitat. This change in spatial distribution may itself reduce population High density area, optimal habitat viability, as growth rate is heavy exploitation reduced in sub-optimal habitat. Low density area, marginal habitat low exploitation M7.31 BIO 3115 Université d’Ottawa / University of Ottawa 2012 Harvest-induced changes in spatial distribution of Gulf cod. Percentage of total stock biomass in regions east of 4T M7.32 BIO 3115 Université d’Ottawa / University of Ottawa 2012 M7.16 BIO 3115 Conservation Biology Consequences of overexploitation IV: exploitive transference 35000 Total Walleye Pike 30000 Annual harvest (kg) as stocks of one species become overexploited, effort turns to the harvest of other species, thereby simply transferring the risk. E.g. on lower Saskatchewan River, as sturgeon stocks were depleted, commerc...
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