Fraser River sockeye salmon: data synthesis and cumulative impacts

I don’t have anything to add beyond what has been recommended.6. Please provide any specific comments for the authors.I like the approach of considering the potential cumulative impacts from a life historyperspective of the fish, i.e. following the fish through their life cycle and consideringexposure to each potential impact along the way. It is unfortunate that the Aquaculturetechnical report was not available to the authors at the time of writing, and theCommission should bear that in mind when evaluating these interim conclusions.Response: We have reiterated this point (i.e. conclusions do not include information onaquaculture) in each of the relevant sections (i.e. Executive Summary, Coastal migrationlife stage (4.4.4, 4.4.5 and 4.4.7), and Conclusions (5.1, 5.2)).The authors have done a good job of summarizing the information from the othertechnical reports, and also compiling data from those reports so that they could do theirown integrative analyses. I agree with their view that the database that they havecompiled could be the first step toward an important long-term resource, and I hope theCommission will consider recommendations that could lead to further development. Ihave always felt that information such as this should be much more accessible, andperhaps long-term funding could be made available to the Pacific Salmon Commissionor some other organization to take this on.Response: In response to a comment by Dr. Peterman on the form of such a database, wehave expanded the discussion in Section 5.2.2.The general analytical approach, involving multiple regressions analyzed within aninformation-theoretic framework, seems like the right way to go. I agree with theauthors’ logic in using multiple partial analyses rather than attempting one grandanalysis, given missing values in data sets, and the need to account for too manyvariables at once. The authors reduced the number of variables through commonsense about which might be informative, as well as through Principal ComponentsAnalysis. They could also have considered using Variance Inflation Factors to test formulticollinearity as a basis for dropping variables, as an alternative or adjunct to the useof PCA. But as long as the PCA axes are interpretable, this approach seems fine.Response: We have substantially improved the clarity of our description of the methods weused (in a new Section 3.3.6, as well as in Appendix 3).The conclusion follows the structure of the rest of the report, in breaking up theanalyses by life stage. But I felt that what’s missing is a final section putting the lifestages back together, and integrating across all of the possible or likely stressors. Inother words, I would have liked to have seen a final section that fully tackles the“cumulative” in cumulative impacts. This would match the detailed section that wasprovided describing what cumulative impacts mean.157