Modeling and simulation of the fish collective behavior with risk perception and startle cascades

In this paper, an improved model of fish collective behavior is proposed, which combines social interactions with the risk perception and startle cascades behavior. By modeling the fast-start of fish individual and the startle propagation processes in fish school, the sudden collective evasion phenomenon during the fish collective behavior is studied. Utilizing this model, the paper focuses on investigating the impacts of cluster patterns and individual heterogeneity in social behavior and risk perception on the collective evasion process through simulations. The results show that the density of cluster aggregation is crucial in determining the propagation capability of startle responses. Conversely, the sudden startle propagation may completely change the type of cluster pattern for the cases in transitional zones. In some scenarios, a very small number of behaviorally heterogeneous individuals can dominate the cluster pattern of the entire group. Finally, it is found that distributing individuals with strong perception abilities around the periphery of the group while clustering those with weaker perception abilities within the inner group enhances the overall perception ability of the entire group.