Meeting Abstract
To capture prey by suction, fishes generate a flow of water that enters the mouth, and exits at the back of the head. It was previously hypothesized that a streamlined shape of the posterior pharynx and the pectoral region of the body are important to enable an unobstructed outflow with minimal hydrodynamic resistance. However, due to the lack of optical access into the pharyngeal cavity, and the limitation of biomechanical models, this hypothesis remained untested. With the help of computational models, allowing a dynamic simulation of both inflow and outflow of water, as well as graphical reconstructions based on CT-scans of a percomorph species of fish (Lepomis gibbosus”), we were able to test the influence of the shape of the buccal cavity on water flow. We found that modifying a wedge-shaped protrusion of the pharynx near the region of the oesophagus entrance into a straight surface perpendicular to the incoming flow has a negligible effect on the dynamics of suction feeding. This suggests that suction feeding does not strongly constrain the shape of this region, which provide new insights on the functional morphology of suction outflow.
