Periodic solution of a bioeconomic fishery model by coincidence degree theory

In this article we use coincidence degree theory to study the existence of a positive periodic solutions to the following bioeconomic model in fishery dynamics (Formula presented) where the functions r, q, A, c and α are continuous positive T-periodic functions. This is the model of a coastal fishery represented as a single site with n(t) is the fish stock biomass, and E(t) is the fishing effort. Examples are given to strengthen our results. ),.