Fraser River sockeye salmon: data synthesis and cumulative impacts

Conceptual modelIn the U.S. Council on Environmental Quality’s handbook Considering Cumulative EffectsUnder the National Environmental Policy Act (1997), it is suggested that conceptual models suchas network diagrams are “often analysts’ best method for identifying the cause-and-effectrelationships that result in cumulative effects.” Within such diagrams or models it is possible toillustrate all relevant components and the linkages among them, with the further flexibility ofrepresenting feedback loops where these relationships are known. Lorne Greig and PeterDuinker, who have written extensively about cumulative effects assessment in Canada, stressthat an appropriate model is an absolutely key component of cumulative effects analysis and anymodels utilized need to be represented explicitly (Greig and Duinker 2008).This project uses a detailed conceptual model as a central framework to which subsequentquantitative analyses and alternative qualitative methods can be connected. This provides acommon structure that can facilitate explicit linkages among a variety of analysis approaches.The conceptual model is used to organize the complex relationships among factors and sockeyesalmon such that the quantitative analyses performed in this project and the synthesis anddiscussion of evidence presented in other projects could be integrated into a singular life historyapproach.The conceptual model presented in the PSC Report was taken as a starting point (Peterman et al.2010). This base model was then further modified based on expert feedback elicited from theparticipants of the science workshop, data submissions from contractors and the technical reportsfrom each of the other projects. The final conceptual model is shown in Figure 3.3-1. Alternaterepresentations of this conceptual model were explored to improve clarity to a variety ofaudiences.Spatial life history diagramOne such permutation of the core conceptual model is a projection of the life history model ontothe Fraser River sockeye salmon’s geographic habitat range where particular stressors can berepresented at the scale at which they potentially affect Fraser River sockeye salmon (Figure 3.3-2). This is a communication tool for illustrating the spatial scale of sockeye salmon’s life cycleas well as critical geographic constraints to non-technical audiences.The two approaches above represent a “bottom-up” perspective for exploring potentialcumulative impacts, detailing where different particular stressors impact sockeye in space andtime. These representations may show where or when sockeye may be exposed to single or201