Fraser River sockeye salmon: data synthesis and cumulative impacts

multiple stresses simultaneously. These frameworks are also useful for representing potentialinteractions or feedback loops among stressors.Relative likelihood of given hypothesesAn alternative “top-down” approach is to rely on expert assessment of the overall likelihood thata particular factor has made a significant contribution to the decline in productivity of FraserRiver sockeye. This approach (building on many sources of evidence) was used by the expertpanel who wrote the PSC report mentioned above (Peterman et al. 2010). At the first workshopfor the Cohen Commission technical research projects, the scientific experts working on eachprojects will examine the judgements made in the PSC report and (if warranted by new evidencenot considered by the PSC panel) make appropriate modifications. Further details of thisapproach will be described in the report on the first workshop (Appendix 6).A3.5.2Quantitative methodsSolicitation of expert feedbackIn early September we organized a meeting with Dr. Randall Peterman and Dr. Carl Schwarz ofSimon Fraser University to solicit their expert advice on potential analytical methods. The twoobjectives of this meeting were to: 1) clarify questions regarding the evaluation of cumulativeand relative impacts; and 2) propose alternative methods for both evaluations, given the types ofdata that we could expect to receive from each research project. The second objective wasapproached via three distinct steps. Step 1 was to identify a broad selection of potential analysesfor further evaluation. Step 2 was to anticipate the types, quality and extent of data sets thatmight be available from each research project in order to prospectively identify potential datalimitations. Step 3 was to critically evaluate each proposed method with respect to project goalsand anticipated data limitations. This evaluation process considered the data input needs, thetypes of output results, the process feasibility, and the overall usefulness of each potentialanalytical method. We then presented a draft analytical plan for review by rest of the CohenContractors at the November 30-December 1 Technical and Scientific Research ProjectsWorkshop. The outcomes of these meetings shaped our analysis framework (Table A3.5-1) andthe data collection process Appendix 5.202