Figure 3

Persistence and stochastic extinction of phytoplankton and fish in system (2). (a) Bifurcation diagram related to \(\delta _{1}\) and \(\delta_{2}\), where I denotes that phytoplankton is persistent but fish are extinct, II implies that phytoplankton and fish are persistent and III indicates that phytoplankton and fish are extinct. (b) The solutions of system (2) with different noise intensities, where (1) for \((\delta_{1},\delta_{2})=(0.1,1.4)\), (2) for \((\delta_{1},\delta_{2})=(0.1,0.2)\) and (3) for \((\delta_{1},\delta_{2})=(1.3,1.4)\)