Optimum Control in a Predator-Prey Model Based on a Two-Species Exploited Ecosystem

Optimum Control in a Predator-Prey Model Based on a Two-Species Exploited Ecosystem

Tatiana Bulgakova

Optimum Control in a Predator-Prey Model Based on a Two-Species Exploited EcosystemThis is part of Ecosystem Approaches for Fisheries Management
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Description

Various "biological reference points" are applied when choosing a rational regime of a fishery for a single species system. In the present paper an attempt has been made to illustrate the necessity of including multispecies considerations in precautionary fisheries management advice. As a starting point for such a precautionary approach it is possible to choose the simplest form of multispecies model which should have at least one steady equilibrium point.

The area of allowable management for a two-species system is constructed using as coordinates the fishing mortality rates of both species and some boundaries of the area that correspond to crash lines for this ecosystem. Trophic interactions of the "predator-prey" type reduce the allowable area of control as compared with areas that would be assumed if the interactions between fish populations were neglected. For example, the point corresponding to the MSY criterion for the prey species lies on the boundary of the allowable area and should be considered as a crash point with respect to the predator population.

The area of allowable control is also constructed for two competing population models. The problem of maximizing economic profit of a two-species fishery in an equilibrium state and during a set time period (for example, one year) inside the allowable area of control is touched upon.

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