Flow Navigation in Larval Zebrafish


March 19, 2014 - 1:00pm
NW 243
About the Speaker
Pablo Oteiza (Engert Lab)

When presented with incoming water flows, aquatic animals actively avoid passive drift by orienting and swimming against the direction of water displacement. This behavior, known as rheotaxis, has been extensively described in several different species and ecological contexts. However, the behavioral mechanisms by which aquatic animals hold position in current streams are largely unknown. Here, we describe the behavioral algorithms by which larval zebrafish perform rheotaxis. Our experiments show that, unexpectedly, this behavior is independent of both visual references and fish body acceleration. Instead, we show that rheotaxis represents the behavioral response of the fish to velocity gradients within the water flow. Our model indicates that during laminar flow navigation zebrafish larvae perform a series of temporal comparisons of water velocity gradients and adjust their trajectory in response to them. Importantly, we demonstrate that the direction of these trajectory changes is determined by a gradient-induced rotation in the fish yaw axis. These results reveal a novel rheotactic strategy based on the integration of temporal gradient sensing and mechanically induced rotation of the animal’s body.