Collective phases and long-term dynamics in a fish school model with burst-and-coast swimming

Abstract

Intermittent and asynchronous burst-and-coast swimming is widely adopted by various species of fish as an energy-efficient locomotion mode. This swimming mode significantly influences the way in which fish integrate information and make decisions in a social context. Here, we introduce a simplified fish school model in which individuals have an asynchronous burst-and-coast swimming mode and selectively interact only with one or two neighbors that exert the largest influence on their behavior and over a limited spatial range. The interactions consist for a fish to be attracted and aligned with these neighbors. We show that, by adjusting the interactions between individuals above a sufficiently high level, depending on the relative strength of attraction and alignment, the model is able to produce a cohesive fish school that replicates the main collective phases observed in nature: schooling, milling and swarming when each individual interacts with only one neighbor, and schooling and swarming when each individual interacts with two neighbors. Moreover, the model shows that these patterns can be maintained over long simulations. However, with the exception of swarming, these patterns do not persist indefinitely in time and fish lose cohesion and progressively disperse. We further identify the mechanisms leading to the dispersion.