A delayed marine bacteriophage infection model

A marine bacteriophage infections model with stage structure is studied. Necessary and sufficient conditions for the extinction and permanence of the system are obtained, which enrich and improve the corresponding results given by S.A. Gourley and Y. Kuang [A delay reaction–diffusion model of the spread of bacteriophage infection, SIAM J. Appl. Math. 65 (2005) 550–566].