UBC Theses and Dissertations
Optimal management of the Fraser River sockeye salmon Gardner, Peter Nigel
The question to which this study is addressed is: can the Eraser River sockeye salmon fishery be managed in such a way as to maximize its present worth? A review of the existing biological and economics literature would suggest that such optimal management is indeed possible. Putting numbers into the theoretical equations and solving for an optimal solution has been based on a three part approach. First, a Ricker form of recruitment function was used to model the basic interseasonal relationship between spawning escapement and subsequent future recruitment. Second, nonlinear production functions were used to model the harvesting process in a highly cyclical fishery spread out over a fairly extensive fishing gauntlet. And third, it is assumed that the manager is faced with two inter-related problems which must be solved simultaneously: he must decide the optimal escapement which has future revenue consequences in terms of size of catch and future cost consequences in terms of size of the subsequent recruitment (the larger the recruitment, the lower the harvesting costs), and he must decide the least cost spatial combination of harvesting gear to take the specified catch. The major finding of this study is that it is possible to manage the Fraser River sockeye salmon fishery in an optimal manner and to do so would increase its present worth substantially. The use of cycle dummy variables to allow for the marked four year cycles in both recruitment and harvesting patterns plays a major role in improving parameter estimation. Nonlinear programming techniques can be developed to allow the simultaneous determination of the optimal intertemporal spawning escapement and the least cost spatial allocation of effort to harvest the optimal catch. The original contribution of this dissertation lies in its use of deterministic models to empirically solve the problem of optimal management of a fishery.
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