Swarm coherence mechanism for jellyfish

We present a model of active Brownian particles for the process of jellyfish swarm formation. The motivation for our analysis is the phenomenon of jellyfish blooming in natural habitats and clustering of jellyfish in laboratory tanks which follow from an interplay of physical and behavioral mechanisms. We reach the conclusion that phase separation at low jellyfish density is induced by behavioral reactions to environmental conditions. Dense regions are then maintained by self-induced stimuli which result in a recruitment process. Our results agree with the biological fact that jellyfish exhibit an extreme sensitivity to stimuli in order to achieve favorable aggregations. Based on our model, we are able to provide a clear terminology for future experimental analysis of jellyfish swarming and we pinpoint potential limitations of tank experiments.