Meeting Abstract
Fishes exhibit an enormous diversity of head shapes, which could have important consequences for how hydrodynamic signals are detected. To explore how head shape affects flow detection by the lateral line canal system, we sought to determine how head width affects vortex detection. We 3D printed fish head models of different widths (1.9, 5.8, 9.3 cm), each with 7 pores arranged horizontally with equidistant spacing (1 cm) starting from the snout. We placed a pressure transducer in each pore and exposed the models to different size vortices, which we generated by placing stationary cylinders of varying diameters (1.3, 2.5, 5 cm) in flow. By measuring signal-to-noise ratios (SNRs), we found a correlation between head width and the SNR detected for each vortex size. Skinny (S) heads detected small vortices better than intermediate (I) and wide (W) heads (S: 31.4±0.9%, I: 20.3±0.9%, W: 17.2±1.1%). Skinny and intermediate heads detected medium vortices similarly, and better than wide heads (S: 36.9±0.4%, I: 35.3±0.5%, W: 28.6±0.7%), whereas intermediate and wide heads detected large vortices better than skinny heads (S: 36.7±0.5%, I: 42.7±0.7%, W: 39.9±0.7%). We also varied flow speeds and found that detection of small and medium vortices did not depend on flow speed for skinny heads but that slower flow enhanced detection for intermediate and wide heads. For all head shapes faster flow enhanced detection of large vortices. We also varied the downstream distance of the heads from the cylinder but found no significant effect. Our results suggest that head width can act as a passive filter for the detection of different sized vortices, which may have implications for the types of hydrodynamic signals available to fishes that vary in head morphology.
