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Potential Effects of Contaminants on Fraser River Sockeye Salmon

Potential Effects of Contaminants on Fraser River Sockeye Salmon

Potential Effects of Contaminants on Fraser River Sockeye Salmon

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8.2 Temporal and Spatial Scope <str<strong>on</strong>g>of</str<strong>on</strong>g> StudyAdverse effects <strong>on</strong> ecological receptors can occur when stressors and receptors arepresent in the same place and at the same time. As such, determinati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> exposure <str<strong>on</strong>g>of</str<strong>on</strong>g>sockeye salm<strong>on</strong> to c<strong>on</strong>taminants in the <strong>Fraser</strong> <strong>River</strong> Basin requires an understanding <str<strong>on</strong>g>of</str<strong>on</strong>g> thelife history <str<strong>on</strong>g>of</str<strong>on</strong>g> this species. Based <strong>on</strong> a review <str<strong>on</strong>g>of</str<strong>on</strong>g> the literature <strong>on</strong> life historycharacteristics, four key time periods when sockeye salm<strong>on</strong> could be exposed toc<strong>on</strong>taminants in freshwater habitats were identified, including:• Spawning and incubati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> sockeye salm<strong>on</strong> eggs and alevins in stream andlakeshore habitats (August 1 to May 31);• Early rearing <str<strong>on</strong>g>of</str<strong>on</strong>g> sockeye salm<strong>on</strong> fry in nursery lakes (April 1 to March 31);• Downstream migrati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> sockeye salm<strong>on</strong> smolts through riverine andestuarine (i.e., <strong>Fraser</strong> <strong>River</strong> and tributaries) habitats (May 1 to June 30); and,• Upstream migrati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> sockeye salm<strong>on</strong> adults through estuarine and riverine(i.e., <strong>Fraser</strong> <strong>River</strong> and tributaries) habitats (June 1 to September 30).<strong>Sockeye</strong> salm<strong>on</strong> utilize spawning and rearing habitats throughout much <str<strong>on</strong>g>of</str<strong>on</strong>g> the <strong>Fraser</strong> <strong>River</strong>Basin. In additi<strong>on</strong>, juvenile and adult sockeye salm<strong>on</strong> utilize migrati<strong>on</strong> corridors withinthe basin. <strong>Sockeye</strong> salm<strong>on</strong> can be exposed to aquatic c<strong>on</strong>taminants in spawning habitats,rearing habitats, and/or migrati<strong>on</strong> corridors. Therefore, it is necessary to identify keyexposure areas within the <strong>Fraser</strong> <strong>River</strong> Basin that are relevant to the various sockeyesalm<strong>on</strong> c<strong>on</strong>servati<strong>on</strong> units. These exposure areas, which are referred to as areas <str<strong>on</strong>g>of</str<strong>on</strong>g>interest, are shown in Figure 2.3.8.3 Aquatic C<strong>on</strong>taminant InventoryLand use informati<strong>on</strong> was compiled for each <str<strong>on</strong>g>of</str<strong>on</strong>g> the areas <str<strong>on</strong>g>of</str<strong>on</strong>g> interest within the study area(Table 3.25; Figures 3.22 to 3.36). In additi<strong>on</strong>, the chemicals that may be released toaquatic ecosystems in c<strong>on</strong>juncti<strong>on</strong> with these land uses were identified (Table 3.26). Thisinformati<strong>on</strong> <strong>on</strong> sources and releases <str<strong>on</strong>g>of</str<strong>on</strong>g> c<strong>on</strong>taminants was then integrated to identify thesubstances that may have been released into aquatic ecosystems within each area <str<strong>on</strong>g>of</str<strong>on</strong>g>interest and the <strong>Fraser</strong> <strong>River</strong> Basin as a whole (i.e., Table 3.27). All <str<strong>on</strong>g>of</str<strong>on</strong>g> the substancesincluded in the Inventory <str<strong>on</strong>g>of</str<strong>on</strong>g> Aquatic <str<strong>on</strong>g>C<strong>on</strong>taminants</str<strong>on</strong>g> (Table 3.28) were c<strong>on</strong>sidered to bechemicals <str<strong>on</strong>g>of</str<strong>on</strong>g> potential c<strong>on</strong>cern in the <strong>Fraser</strong> <strong>River</strong> Basin.133

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