Meeting Abstract
Many marine fishes from divergent teleost lineages hide in the substrate to avoid predators or to ambush prey, but the mechanisms by which fishes insert their bodies into the substrate are still poorly understood. We examined the kinematics of burial in the Pacific staghorn sculpin (Leptocottus armatus) and asked: how does the deep-bodied sculpin bury its body into the substrate? We filmed L. armatus individuals (n=7) voluntarily burying using two high speed cameras (recording images from synchronized dorsal and lateral views) and tracked points on the fish over time using a MatLab routine (DLT data viewer, created by Ty Hendrick). Displacement data for each tracked point (head, tail and body) were subsequently smoothed with a quintic smoothing spline to derive velocity and acceleration. The Pacific staghorn sculpin buries by raising its head and tail simultaneously, then forcefully bringing both ends of the body downward, onto the substrate. During the down-stroke, the sculpin appears to simultaneously force water out of the ventral margin of the opercles (gill cover) to inject water into the sand. Pacific staghorn sculpins also use their pectoral fins to push sand laterally out from underneath the body and they alternate fin movements over time. Dorso-ventral body movements and pectoral fin movements are repeated cyclically at approximately 0.75-second intervals until the fish is approximately 60% buried. It appears that Pacific staghorn sculpins use a combination of undulations, injection of water into the substrate from the cranium, and physical removal of substrate by the pectoral fins during burial behaviors. These data provide ecologically significant insights into the behavior of this species, but also may provide new mechanisms to bury human infrastructure and equipment (bridges or ship anchors) into sandy substrates.
