Function of lateral line canal morphology.

Fish perceive water motions and pressure gradients with their lateral line. Lateral line information is used for prey detection, spatial orientation, predator avoidance, schooling behavior, intraspecific communication and station holding. The lateral line of most fishes consists of superficial neuromasts (SNs) and canal neuromasts (CNs). The distribution of SNs and CNs shows a high degree of variation among fishes. Researchers have speculated for decades about the functional significance of this diversity, often without any conclusive answers. Klein et al. (2013) examined how tubules, pore number and pore patterns affect the filter properties of lateral line canals in a marine teleost, the black prickleback (Xiphister atropurpureus). A preliminary mathematical model was formulated and biomimetic sensors were built. For the present study the mathematical model was extended to understand the major underlying principle of how canal dimensions influence the filter properties of the lateral line. Both the extended mathematical model and the sensor experiments show that the number and distribution of pores determine the spatial filter properties of the lateral line. In an environment with little hydrodynamic noise, simple and complex lateral line canals have comparable response properties. However, if exposed to highly turbulent conditions, canals with numerous widely spaced pores increase the signal to noise ratio significantly.