Pattern Selection of Shallow Suspensions of Shrimp

Swarming, a self-organization phenomenon which occurs in many biological systems, can emerge spontaneously, arising without any sort of centralized control or leadership. Many crustaceans, such as brine shrimp, produce swarms, in which individuals cluster together rather than spreading out uniformly in their environment. The motion of these crustaceans is also affected by light due to their phototactic nature. The size and distribution of these swarms are governed by local interactions between individuals but are also affected by the boundaries of the container. We discuss the three-dimensional patterns that can be observed in brine shrimp swarms, specifically of the Great Salt Lake strain of Artemia franciscana, at high concentration . We experimentally test the effects of average concentration, temperature, and container size on the basic length and times scales of the patterns, the type patterns selected, and the stability of those patterns. We then discuss the physical mechanism behind the formation and selection of these patterns.