Fraser River Sockeye Fisheries and Fisheries Management - Cohen ...

could be better continuity and synthesis across the various tasks and sections. For instance, catchmonitoring (Fisheries Harvesting section) was not as good prior to 2001 as it is now, and theauthors suggest that historical catch was probably under-estimated. Yet, such under-estimationwas not discussed in the "Extent of Overharvesting" sub-section later where, in some cases, theauthors suggest that high harvest rates may have been "sustainable". The latter sub-section coulduse some discussion of the implications of under-estimating historical harvest rates. Thus, ingeneral, the report could use a Synthesis section that presents the author's view on the key issuesin Fraser River sockeye fisheries assessment and management.There is some inconsistency in application and presentation of data accuracy, precision, andreliability metrics, which is understandable given the breadth of information included in thereport. For instance, pages 5/6 are devoted to explaining how accuracy, precision, and reliabilitywere determined, and then, on page 7, a new, qualitative scaling is introduced that seemsdifferent. This apparently different set of criteria leaves me wondering which method is going tobe used and when.LGL Response: We will clarify in the report that the definitions of accuracy and precisionprovided on page 5/6 are for quantitative assessments and to distinguish betweenevaluations of methods and evaluations of estimates. Quantitative assessments of accuracyare limited to pre-season and in-season forecasts where the final run size estimates are the“true” values that we are trying to forecast. Quantitative assessments of precision arepossible for some catch and escapement estimates. The definitions provided on page 7 areused to provide a qualitative summary of our findings related to sockeye catch estimates. Itis not possible to quantitatively assess the accuracy of catch estimates because the truecatch is not known. The available information on the precision of catch estimates is notsufficient to produce a quantitative summary for all fisheries.2. Evaluate the interpretation of the available data, and the validity of any derivedconclusions. Overall, does the report represent the best scientific interpretation of theavailable data?Some analyses present basic statistics (e.g., correlations, regressions) as indicators of accuracy,precision, or reliability. I think of at least four issues arising from the use of these statistics: (i)the use of correlation/regression analyses over-state the "reliability" of both pre-season and inseasonforecasting methods. Table 21 uses regressions to indicate reliability, precision, andaccuracy, yet the regression statistics are not even close to independent, and the associations toquality are vague. The Median Absolute Percent Errors in forecasts are pretty large and notconsistent with any of the regression statistics. (ii) one cannot judge reliability of in-seasonforecasts without considering the timing of these forecasts relative to timing of fisheries. In-M-27