Pelicans at risk in Salton sea - an eco-epidemiological model

The effect of diseases in ecological system is an important issue from math ematical and experimental point of view. A mathematical model for the susce ptible Tilapia population, infected Tilapia population and their predator P elican birds population is proposed and its essential mathematical features are analyzed. A threshold phenomenon. 'basic reproductive ratio R-o' of ep idemic theory is defined. Local and global stability of the system around t he biological feasible equilibria is presented. Conditions for persistence of the system are worked out. It is observed that if the level of the searc h rate of predator is low, the system around the positive interior equilibr ium is stable. But the instability sets in with the increase of search rate level of predator. We conclude that for sustainability of Tilapia on Pelic ans in the Salton sea, reduction of Tilapia population in a considerable am ount is: required. Numerical examples and computer simulations are also pre sented to validate our analytical findings. (C) 2001 Elsevier Science B.V. All rights reserved.