Fraser River sockeye salmon: data synthesis and cumulative impacts

these integrative frameworks, converging to conclusions about the relative likelihood of differentfactors explaining observed patterns in Fraser sockeye productivity. One difficulty in this processis that each researcher used their own approach for synthesizing and organizing information.Thus we recognized that the third step would involve mining key findings within each technicalreport that fit our integrative framework, and then assess potential cumulative impacts within andbetween life history stages.4. Quantitative Analyses of Cumulative Impacts. We first determined reasonable hypothesesworth testing, given plausible mechanisms of impact on sockeye as outlined in the CohenCommission Technical Reports. To the extent possible given available data, we then completedstatistical analyses to determine the relative ability of various factors (representing differentcombinations of stressors) to explain changing patterns of productivity in Fraser sockeye. Wherefeasible, we incorporated quantitative analyses into the Integrative Analyses of CumulativeImpacts (objective 3 above).5. Clear Communication. This is a cross-cutting objective, namely to clearly communicate howthe stressors examined by the Cohen Commission research projects could interact to affect FraserRiver sockeye. The intent of this objective is to develop methods of presenting and reporting keyfindings that will be accessible to the diverse audiences interested in the work of the CohenCommission, including Judge Cohen and the Cohen Commission scientific and legal staff,Cohen Commission Participants, interested members of the public, research contractors, and peerreviewers.1.2 Report OverviewThis technical report is organized into the following sections:Section 2.0: Cumulative Impacts or EffectsThis section introduces the concept of cumulative impacts or cumulative effects, some key ideasassociated with this concept, and their application to this project.Section 3.0: Complexity, Caveats and Overall ApproachThis section describes the approach we used to synthesize and integrate evidence across otherassociated technical reports, first identifying some of the overarching limitations on this type ofanalysis (e.g., the inherent complexity of the underlying ecological system, the significant gapsin our knowledge), and how these limitations enact constraints on the ability to make definitiveconclusions about cause-effect relationships.2