Bifurcations and Periodic Solutions for an Algae-Fish Semicontinuous System

Figure 6

Existence of an order-1 periodic solution for system (1) versus the parameters 𝑝 and 𝑞. In the black zone, there always exists an order-1 periodic solution in system (1). Note: this figure does not mean that there is no order-1 periodic solution in system (1).