Meeting Abstract

7.5  Thursday, Jan. 3  Locomotor plasticity of larval zebrafish in high viscosity environments DANOS, N.; Harvard University ndanos@fas.harvard.edu

Routine turns are a normal part of the zebrafish foraging behavior that provides a good context in which to study the developmental plasticity of locomotor behavior. Zebrafish are raised from 0 to 6 days post fertilization in water whose viscosity has been increased by the addition of a large polysaccharide. Five viscosity treatments are applied to different groups of larval zebrafish, the highest viscosity treatment being 50 times as viscous as normal water. At the end of this period 3 fish from each treatment are filmed performing routine turns in their growth medium. They are then transferred into water of normal viscosity, allowed to acclimate for 30 minutes, and then filmed again. Filming is repeated after 24 hours in normal viscosity water. Conversely, zebrafish raised in water are transferred to higher viscosity water and filmed after 30 minute and 24 hour acclimation periods. Kinematic variables such as linear body velocity are obtained using Digital Particle Image Velocimetry software. I hypothesize that if fish aim for an optimum in foraging, i.e. maximum area searched as measured by the product of turn frequency and body curvature, turning kinematics of fish in their native viscosities should be indistinguishable. However, if the behavior is determined by mechanosensory input or by morphological changes resulting from the treatment, the kinematics of fish in the various treatments will differ. In order to differentiate morphological changes from behavioral ones I quantify the turning kinematics of the fish after 24 hours in normal water. If the changes are completely plastic, fish�s behavior after this period should be indistinguishable from that of fish raised in normal water. If, however, the mechanosensory input led to irreversible neurological or morphological changes, fish raised in higher viscosities should perform routine turns with increased angular velocity in water.