Meeting Abstract

P1.107  Saturday, Jan. 4 15:30  The Effects of Self Motion on the Pressure Difference Across the Head of Rainbow Trout (Oncorhynchus mykiss) During Locomotion YANAGITSURU, Y.R.*; AKANYETI, O; LIAO, J.C.; University of California, San Diego; Whitney Laboratory for Marine Bioscience; Whitney Laboratory for Marine Bioscience yyanagit@ucsd.edu

The self-generated pressure gradient across a fish’s head during locomotion affects both hydrodynamic efficiency and the ability to sense flow signals. By head-mounting pressure sensors and synchronizing them to high speed video cameras recording lateral and ventral views, we simultaneously measured the head kinematics and hydrodynamic pressure gradients for rainbow trout during steady swimming (L=18.7±1.1 cm, 2-7 L s^-1, n=5 fish). We find that the pressure gradient increases quadratically as steady swimming speed increases, which correlates with the inability of the fish to sustain steady swimming above 4 L s^-1. We have also begun to look at the pressure gradients generated by other motor behaviors such as Karmán gaiting in a vortex street behind a cylinder, bursting, and C-starting. Preliminary data shows that for a fish Karmán gaiting among vortices in a cylinder wake, the pressure gradient is ten times that of steady swimming and also increases quadratically with flow speed. For transient behaviors such as bursting the pressure gradient depends upon burst speed, and is always higher than that of steady swimming. Remarkably, during a C-start the pressure gradient is over one thousand times that of steady swimming. We find that, overall, the intensity of the self-generated pressure gradient is inversely correlated with the duration of a behavior. Our study lays the groundwork to better understand the effects of self-motion on both locomotor efficiency and sensory functions.