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Map illustrating the Fraser River Basin with our Area of Interest highlighted in blue (Thompson watersheds). The existing and proposed TMX pipeline route overlays our study boundaries.

Map illustrating the Fraser River Basin with our Area of Interest highlighted in blue (Thompson watersheds). The existing and proposed TMX pipeline route overlays our study boundaries.

Contexts in source publication

Context 1
... address this complexity in their lifecycle, we grouped Chinook salmon based on their use of the watershed (mainstem of the river compared to two grouping types for tributaries. Figure 10. The assumed spill coverage for Chinook by scenario, life history parameter and grouping by watershed origin. ...
Context 2
... assumed spill coverage for Chinook by scenario, life history parameter and grouping by watershed origin. Life cycle parameters on the x axis represent transitions between life stages which includes pre-spawning adult to spawning adult (P2A), fry to smolt (F2S), sublethal impacts to future fecundity for exposed cohorts (F, number of eggs a female will lay) and egg to fry (E2F) (Table A1 in Figure 11. The assumed spill coverage for Sockeye by scenario, life history parameter and grouping by watershed origin. ...
Context 3
... assumed spill coverage for Sockeye by scenario, life history parameter and grouping by watershed origin. Life cycle parameters on the x axis represent transitions between life stages which includes pre-spawning adult to spawning adult (P2A), fry to smolt (F2S), sublethal impacts to future fecundity for exposed cohorts (F, number of eggs a female will lay) and egg to fry (E2F) ( Figure 12. The total impact as the % reduction in returning adult abundance for Chinook by scenario and grouping (given the assumed life-history parameters, impacts and coverage Figure 13. ...
Context 4
... cycle parameters on the x axis represent transitions between life stages which includes pre-spawning adult to spawning adult (P2A), fry to smolt (F2S), sublethal impacts to future fecundity for exposed cohorts (F, number of eggs a female will lay) and egg to fry (E2F) ( Figure 12. The total impact as the % reduction in returning adult abundance for Chinook by scenario and grouping (given the assumed life-history parameters, impacts and coverage Figure 13. The total impact as the % reduction in returning adult abundance for Sockeye by scenario and grouping (given the assumed life-history parameters, impacts and coverage Figure 14. ...
Context 5
... total impact as the % reduction in returning adult abundance for Chinook by scenario and grouping (given the assumed life-history parameters, impacts and coverage Figure 13. The total impact as the % reduction in returning adult abundance for Sockeye by scenario and grouping (given the assumed life-history parameters, impacts and coverage Figure 14. The site-level spawner counts (plotted on a logarithmic scale) by spawner year and conservation unit for Chinook salmon. ...
Context 6
... site-level spawner counts (plotted on a logarithmic scale) by spawner year and conservation unit for Chinook salmon. Figure 15. The site-level spawner counts (plotted on a logarithmic scale) by spawn year and conservation unit for Sockeye salmon. ...
Context 7
... site-level spawner counts (plotted on a logarithmic scale) by spawn year and conservation unit for Sockeye salmon. Figure 18. The estimated impact of a diluted bitumen spill by year (with 95% confidence intervals Table 9. ...
Context 8
... study focused on the Thompson watershed within the larger Fraser Basin watershed in British Columbia (BC), Canada ( Figure 1). The TMX pipeline route closely follows the North Thompson River for about 275 km from south of Albreda, BC to just west of Kamloops, BC, where it crosses the Thompson River upstream of Kamloops Lake (see Figure 2 below). ...
Context 9
... present how each of the seasonal scenarios were likely to impact baseline survival for any salmon directly exposed to the contaminants from a 4,000 m3 spill. We now need to understand, how much of the population from each of the above spatial groupings (e.g., populations of the tributary, mainstem, and Barriere CU groupings (Figures 8 and 9) might be exposed to that impact because each of the spill scenarios were presumed to impact the life cycle of these groupings in different ways ( Figures 10 and 11, Table A12 in Appendix A). We compiled this initial assessment of the likely spatial coverage of impacts across the Chinook and Sockeye life cycle using the timing of fry, smolt, and spawning migrations and usage of the North Thompson watershed. ...
Context 10
... impacts in fry-to-smolt survival varied by season and species. Sockeye fry-to-smolt survival was reduced for 100% of fry that reared in Kamloops Lake across all scenarios ('Main' and 'Tribs' groupings in Figures 8 and 11). However, fry-to-smolt survival for the Barriere CU were presumed to experience 20% of this impact in the Freshet spill scenario due to limited direct exposure passing through Kamloops Lake during their outmigration -this impact would be 0% for all other scenarios as they would be outside of the vulnerable area of the watershed ('Tribs2' groups in Figures 8 and 11). ...
Context 11
... fry-to-smolt survival was reduced for 100% of fry that reared in Kamloops Lake across all scenarios ('Main' and 'Tribs' groupings in Figures 8 and 11). However, fry-to-smolt survival for the Barriere CU were presumed to experience 20% of this impact in the Freshet spill scenario due to limited direct exposure passing through Kamloops Lake during their outmigration -this impact would be 0% for all other scenarios as they would be outside of the vulnerable area of the watershed ('Tribs2' groups in Figures 8 and 11). Chinook fry-to-smolt survival was reduced for only 20% for the tributary populations to the North Thompson as most smolts appear to rear downstream of the vulnerable area, and 80% for the mainstem population as many fry were presumed to already be settled into their rearing habitat within the mainstem (Figures 9 and 10). ...
Context 12
... fry-to-smolt survival for the Barriere CU were presumed to experience 20% of this impact in the Freshet spill scenario due to limited direct exposure passing through Kamloops Lake during their outmigration -this impact would be 0% for all other scenarios as they would be outside of the vulnerable area of the watershed ('Tribs2' groups in Figures 8 and 11). Chinook fry-to-smolt survival was reduced for only 20% for the tributary populations to the North Thompson as most smolts appear to rear downstream of the vulnerable area, and 80% for the mainstem population as many fry were presumed to already be settled into their rearing habitat within the mainstem (Figures 9 and 10). ...
Context 13
... spatial coverage of impacts to Sockeye onroute spawning mortality covered 100% of the adults spawning in the mainstem North Thompson, and 50% for any tributary populations (including the Barriere CU) due to limited direct exposure of a Fall spill for adults onroute during spawning migrations. Impacts to Chinook onroute spawning mortality covered 100% of adults spawning in the mainstem North Thompson and 50% of adults spawning in the tributary due to limited exposure as returning adults still pass through the mainstem on their way to the tributary (Figures 9 and 10). ...
Context 14
... coverage of impacts to egg-to-fry survival varied by species, season, and between the mainstem and tributary populations. For Fall and Winter spill scenarios, we assumed that 100% of the impact to egg-tofry survival for Chinook (Figures 9 and 10) and Sockeye (Figures 8 and 11) spawned in from the mainstem North Thompson River. This impact is reduced to 0% for the Freshet scenario as fry have already emerged to begin their migration into their rearing habitats (this emerging cohort could be vulnerable to a fry-tosmolt impact). ...
Context 15
... coverage of impacts to egg-to-fry survival varied by species, season, and between the mainstem and tributary populations. For Fall and Winter spill scenarios, we assumed that 100% of the impact to egg-tofry survival for Chinook (Figures 9 and 10) and Sockeye (Figures 8 and 11) spawned in from the mainstem North Thompson River. This impact is reduced to 0% for the Freshet scenario as fry have already emerged to begin their migration into their rearing habitats (this emerging cohort could be vulnerable to a fry-tosmolt impact). ...
Context 16
... impact is reduced to 0% for the Freshet scenario as fry have already emerged to begin their migration into their rearing habitats (this emerging cohort could be vulnerable to a fry-tosmolt impact). For all scenarios, there is 0% impact to egg-to-fry survival from the tributary populations for both species as they would be rearing in their natal streams outside the impacted area prior to fry migration ( Figures 10 and 11). ...
Context 17
... sublethal impact of reduced fecundity as a result of diluted bitumen exposure was presumed to affect 100% of returning adult Sockeye that reared in Kamloops Lake as fry and 0% of adults from Barriere CU (Figures 8 and 11). For Chinook, sublethal impacts were presumed to affect 100% of returning adults from the mainstem but only 20% of returning adults from the tributaries as exposure would be more limited as developing fry from the tributaries reared outside the affected area and only migrated through the area during a limited period of time (Figures 9 and 10). ...
Context 18
... sublethal impact of reduced fecundity as a result of diluted bitumen exposure was presumed to affect 100% of returning adult Sockeye that reared in Kamloops Lake as fry and 0% of adults from Barriere CU (Figures 8 and 11). For Chinook, sublethal impacts were presumed to affect 100% of returning adults from the mainstem but only 20% of returning adults from the tributaries as exposure would be more limited as developing fry from the tributaries reared outside the affected area and only migrated through the area during a limited period of time (Figures 9 and 10). (Table A1 in Appendix A). ...
Context 19
... general, a large spill from TMX could lead to as much as 71% and 73% fewer returning adult Chinook and Sockeye, respectively, to the North Thompson (based on assumptions and knowledge from the literature review) (Figures 12 and 13). Impacts to freshwater survival were modelled to lead to fewer adult salmon to support both population resilience and fishery resources. ...
Context 20
... our hypothetical scenarios, Tables 9 and 10 represent the degree of mortality of returning adults we would see following a spill either during freshet, fall or winter in either of the main stem of the North Thompson or its tributaries. For Indigenous, commercial, and recreational fisheries that rely upon the returning adult salmon from these areas, this may mean they see 71% fewer Chinook salmon (from 1,921 adults currently to 557 adults after the worst impact; Figure 12) and 73% fewer Sockeye salmon available for harvest (from 8,992 Sockeye adults currently to 2,427 after the worst impact; Figure 13). There would likely be spatial variation in these declines across the watershed, and fishing communities that rely upon tributary or other Conservation Units may not see as large of an impact to their returning salmon as those fishing on the mainstem North Thompson River. ...
Context 21
... our hypothetical scenarios, Tables 9 and 10 represent the degree of mortality of returning adults we would see following a spill either during freshet, fall or winter in either of the main stem of the North Thompson or its tributaries. For Indigenous, commercial, and recreational fisheries that rely upon the returning adult salmon from these areas, this may mean they see 71% fewer Chinook salmon (from 1,921 adults currently to 557 adults after the worst impact; Figure 12) and 73% fewer Sockeye salmon available for harvest (from 8,992 Sockeye adults currently to 2,427 after the worst impact; Figure 13). There would likely be spatial variation in these declines across the watershed, and fishing communities that rely upon tributary or other Conservation Units may not see as large of an impact to their returning salmon as those fishing on the mainstem North Thompson River. ...
Context 22
... the power analysis, we are trying to detect trends in a specific river in a watershed so we need to account for the natural variability at each of these spatial scales. Figures 14 and 15 below show just how much variability exists in returning adult numbers at different locations in the watershed from one year to the next. ...
Context 23
... empirical model estimated that across the Fraser Basin, Chinook salmon declined in the 1950s, increased from 1960 to around 2000 and have been declining at an accelerating rate for the past 20 years ( Figure 16). The same model estimated that Sockeye salmon have been in decline in the Fraser Basin for the past 30 years ( Figure 17). ...
Context 24
... empirical model estimated that across the Fraser Basin, Chinook salmon declined in the 1950s, increased from 1960 to around 2000 and have been declining at an accelerating rate for the past 20 years ( Figure 16). The same model estimated that Sockeye salmon have been in decline in the Fraser Basin for the past 30 years ( Figure 17). The model accounted for these trends so that they would not affect the ability of the empirical model to detect an impact from our oil spill scenarios. ...
Context 25
... results indicate that the adult return data is too variable within and between conservation units from one year to the next to reliably quantify the impacts of a large spill ( Figure 18). The results also indicate that despite allowing for annual and intra-annual within unit random effects the model fails to adequately account for all of the sources of variation in the North Thompson. ...
Context 26
... various systems were grouped as follows in Table A12 and is represented in Figures 10 and 11 in the main report. ...