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Fishery Bulletin )05(4) 



0) 



6 8 10 12 



4 -f 

 2 

 

 -2 



4 



2 







-2 



-4 



10 



12 



20 40 60 80 100 120 



200 400 600 800 1000 1200 1400 



Observed recoveries 



Figure 6 



Distribution of mean posterior predictive standardized residuals showing plausibility of observed 

 data, given the model and error structure. Residuals were calculated by dividing the raw residual 

 between the observed value and the X"' percentile of the posterior predictive distribution by the 

 expected standard deviation and by taking the mean of these values for each data type (type 1, 

 where data were available for year, month, and PFMC area for each individual tag recovery; type 

 2, where data were only available for only month and area; type 3, where data were available for 

 area only; and type 4, where data were only available to indicate recovery inside or outside the 

 area of tagging) and percentile of the posterior predictive distribution. 



has been demonstrated for English sole but could be ex- 

 tended to other species that have also been the subject 

 of multiple tagging projects. When compared with the 

 status quo assumptions invoked with single (unit I or 

 multiple independent stocks, these results may provide 

 a more realistic integration of spatial movement off the 

 west coast of North America into assessment models. 

 Use of these results could lead to a better representa- 

 tion of the uncertainty associated with estimates of 

 biomass and in the case of stock assessments, they 

 could lead to predictions of exploitation rates that allow 

 a sustainable resource. 



Acknowledgments 



T. Branch, D. Gunderson, A. Magnusson, C. Minte-Vera, 

 and A. Silva all generously assisted with data sources 

 or analysis. This article was significantly improved by 

 comments on preliminary drafts from T. Branch, R. 

 Hilborn, R. Methot, A. Punt, and I. Taylor. Three anony- 

 mous reviewers and A. Moles made many suggestions 

 improving the clarity and content of the manuscript. 

 The author was supported by a National Marine Fisher- 

 ies Service/National Sea Grant fellowship in population 

 dynamics. 



