Schooling Behavior in Fishes

Fish schooling and aggregation behaviors are some of the most prominent social and group activities exhibited by fishes. Fish may school or form aggregations for many reasons, including foraging, reproduction, and defense from predators. One of the most enduring hypotheses regarding fish schooling is that fish in schools can obtain a hydrodynamic advantage, thus reducing the cost of locomotion, by taking advantage of the wakes shed by neighbors within the school.

We have been studying the kinematics and hydrodynamics of schooling fishes by using 3D kinematic techniques to track the positions of fishes within small (3 – 10 individual) schools in our laboratory flow tanks, and by using a novel custom laser-scanning device to image flow within schooling groups of fishes. Our laser-scanning system involves using two lasers simultaneously and two rotating mirror drums to sweep laser beams through the school. This results in a near-3D image of the flow within the school, and also eliminates shadows cast by individual fish, allowing detailed imaging of flow in between adjacent fish within the school.