Meeting Abstract
The capturing of prey in a dense and viscous environment presents many hydrodynamic challenges for aquatic organisms. Suction-feeding fishes, like bluegill, have solved this problem by coordinating the timing of feeding movements (e.g., peak gape and peak premaxillary protrusion) in an all-or-nothing rapid expansion of the head. These peak movements are correlated with peak flow that draws prey into the buccal cavity. While this suction-feeding mechanism is common, goldfish have been previously shown to not fit this exact model. It has been observed that goldfish can sustain maximal flow for longer than bluegill, but the kinematics behind generating this flow profile are not yet known. Goldfish are members of the order Cypriniformes, a diverse group of freshwater fishes that all have a kinethmoid bone that aids in premaxillary protrusion and is not present in other fishes. In this study, we sought to quantify the relationship between morphological and kinematic variables of cypriniform feeding mechanisms. Because goldfish may not represent all cypriniforms, sixteen species were analyzed to attain a broad, phylogenetic sampling of this diverse order. Based on collected kinematic data of cypriniform feeding mechanisms, several patterns emerged. Bottom-feeding species show similar patterns to goldfish with sustained protrusion and slower times to peak gape while more derived species mirror bluegills and non-cypriniform kinematics with a faster time to peak gape and non-sustained protrusion. These findings suggest that cypriniforms do not fit a single model of suction-feeding and that diverse strategies for prey capture are found across the order.
