| Popis: |
This paper arises out of a collaborative project to investigate fishery management, which poses problems of control in the presence of uncertainty, from the point of view of control engineering, which uses dynamic, but not necessarily optimal, feedback controllers to solve such problems. Management of one particular isolated population (the Western stock of mackerel) is considered in detail in order to show applicability of established techniques in control engineering. The control problem is seen to be nonlinear, as well as stochastic. A new single-state fishery model is presented. General results from the engineering analysis, in the form of strategies of constant catch and of constant effort and in the form of a warning about the instability of high exploitation, confirm what is well known in fishery management. Numerical data are obtained which could be used to design a controller minimising fluctuations about a chosen equilibrium state. It is concluded that control engineering provides a suitable scientific framework for further discussion of fishery management and of other problems of regulating harvested populations. |
