Meeting Abstract
Flatfishes bury themselves under a thin layer of sand to hide from predators or to ambush prey. We investigated the role of body undulation frequency in burial in five species of flatfishes (Isopsetta isolepis, Lepidopsetta bilineata, Parophrys vetulus, Lyopsetta exilis, and Psettichthys melanostictus). High speed videos show that undulations begin cranially and pass caudally while burying, as in forward swimming in many other fishes. They also flick their dorsal and anal fins during burial, apparently to guide jets of fluidized sand. A physical model – a silicone model flatfish with a motorized, variable-speed actuator – was built to isolate the effect of undulation speed on burial. The model suggests that increased frequency increases the area of sand coverage. However, this benefit leveled off at higher speeds, which suggests there is an optimal range of undulation frequency that allows for the most efficient burial. The model shows undulation is sufficient to bury the animal, but the live flatfishes showed a superior ability to bury, which we attribute to the action of the median fins. We suggest that body undulations offer a means for a fish to bury itself which is enhanced through the independent action of its fins.
