Accurate catch estimates are integral to the assessment of fish stocks and the development and application of harvest rules for sustainable fisheries management. As with spawning escapement estimates, accurate and timely catch information is the currency upon which all higher level management functions are based. The need to routinely produce precision estimates (confidence limits and standard errors) in addition to point estimates of catch is an expected standard practice. In recent times, salmon managers often find themselves sequestered in postseason review exercises to account for “fish have gone missing”. These assessments are often based on comparisons of point estimates of (a) fish estimated to have escaped past Mission; (b) catch estimates in the gauntlet of fisheries (ocean commercial, commercial inriver, First Nation inriver, ocean and inriver sport); (c) estimates of prespawn / enroute migration mortality; and (d) estimates of final spawning escapement. Error estimates in all these variables must be understood to set a proper context for what proportion of any “missing fish” can simply be explained by sample variability and measurement error (Figure 1). Figure 1: Significance of precision estimates in postseason accounting MERCI Precision Estimation Tool (PET) is a
standalone software package designed to estimate precision of bootstrap
simulation data generated by the MERCI software. The outputs generated by
MERCI PET include estimates for catch, CPUE, and effort with the corresponding
estimates of precision: standard error and (biascorrected) confidence
intervals. The program uses a combination of a Visual Basic .NET User Interface coupled with the statistical computing power of R: A Language and Environment for Statistical Computing. This online help site provides a walkthrough of
