Some implications of predation to optimal management of Marine Resources

The report studies the influence predation has on optimal management of renewable resources, i.e. fish stocks. We determine the optimal harvest as a function of the current value of the resource stock by introducing feedback controls. We consider two interacting species and observe how predation influences the optimal harvest for both species. The prey stock is described by a growth curve with depensation, the predator by the logistic growth function. Nonlinear profit functions are adopted. We present an example of a predator-prey problem and discuss the effects from changing some parameters. The depensation growth curve is reflected in our results by a critical level for prey increasing with a higher stock of predator. When the prey stock is close to its critical level from above, our results indicate an increased harvest of predator.