An Evaluation Of Two Preseason Forecasting Techniques Using Transformed And Untransformed Abundances Of Sibling Age Class Returns Of Sockeye Salmon Oncorhynchus Nerka With Possible Economic Implications Microform

Author : Catherine Anne (Carrie) Holt
Publisher :
ISBN 13 :
Total Pages : 454 pages
Book Rating : 4.:/5 (112 download)

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Download or read book Characterizing and Accounting for Uncertainties in Pacific Salmon Fisheries written by Catherine Anne (Carrie) Holt and published by . This book was released on 2007 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: Uncertainties are widespread in Pacific salmon fisheries, occurring in both biological and management components. Despite recent attempts by scientists to account for uncertainties in stock assessments and incorporate them into advice to managers, some sources of uncertainties are often still ignored. My dissertation addressed four of these sources for Pacific salmon fisheries related to: forecasts of adult abundances, effectiveness of fishing regulations when implemented, the ability of management to achieve stated objectives, and international management institutions. First, despite evidence for long-term increases in age-at-maturity of sockeye salmon (Oncorhynchus nerka), these increases have not been accounted for when forecasting age-specific abundances of adult returns. To account for these trends, I developed a new forecasting model that used a Kalman Filter to track long-term changes in its parameters. Second, stock assessors and managers often assume that management targets are achieved exactly, but outcomes from fishing regulations rarely match targets. I quantified bias and imprecision in this "outcome uncertainty" for sockeye salmon fisheries on the Fraser River, British Columbia, and developed a method to adjust current harvest rules for that source of uncertainty. Third, although my research suggests that these two modifications to forecasting models and harvest rules are feasible, the magnitude of improved performance of management that includes these modifications is not certain. I evaluated the performance of these two modifications in a computer model for sockeye salmon fisheries in British Columbia and Alaska. I found that, compared to the status quo, performance increased when outcome uncertainties were accounted for, but in contrast to initial expectations, this was not the case when accounting for forecasting uncertainty. Fourth, salmon body sizes at a given age have declined across the North Pacific over the last fifty years, in part due to increased competition among salmon populations from different countries for a common pool of prey resources. However, the incentives for collective action to reverse this trend are not clear, creating uncertainties in resolving this common-pool resource problem. I investigated the potential for international cooperation on this problem by identifying the incentives and disincentives for altering behaviour of individual nation states to encourage collective action.