Lateral Line - Function

Function

The lateral line system allows the detection of movement and vibrations in the water surrounding an animal, providing spatial awareness and the ability to navigate in space. This plays an essential role in orientation, predatory behavior, and social schooling.

In a 2001 study, researchers demonstrated that the lateral line system was necessary to detect vibrations made by prey and to orient towards the source to begin predatory action. Fish were able to detect movement, produced either by prey or a vibrating metal sphere, and orient themselves toward the source before proceeding to make a predatory strike at it. This behavior persisted even in blinded fish, but was greatly diminished when lateral line function was inhibited by CoCl₂ application. This cobalt chloride treatment results in the release of Co ions, disrupting ionic transport and preventing signal transduction in the lateral lines. Further trials utilizing either a gentamicin dip or external scraping of the lateral lines, to disrupt canal and superficial receptors respectively, demonstrated that these behaviors were dependent specifically on mechanoreceptors located within the canals of the lateral line.

The role mechanoreception plays in schooling behavior was demonstrated in a 1976 study by Pitcher, et al. A school of Pollachius virens was established in a tank and individual fish were removed and subjected to different procedures before their ability to rejoin the school was observed. Fish that were experimentally blinded were able to reintegrate into the school, while fish with severed lateral lines were unable to reintegrate themselves. Therefore, reliance on functional mechanoreception, not vision, is essential for schooling behavior.