Harvesting of a prey-predator fishery in the presence of toxicity

In this model we discuss the bioeconomic harvesting of a prey-predator fishery in which both the species are infected by some toxicants released by some other species. Here both the species are harvested where we use the usual catch-per-unit-effort hypothesis. The dynamical behaviour of the exploited system is examined. The possibility of existence of a bionomic equilibrium is considered. The optimal harvesting policy is studied by using Pontryagin's maximal principle. Some numerical examples and the corresponding solution curves are studied to illustrate the results of the model. Finally, the existence of limit cycle is discussed. (c) 2008 Elsevier Inc. All rights reserved.