Saltatory search in a lateral line predator

Abstract

The dwarf scorpionfish Scorpaena papillosa detected the hydrodynamic signals produced by prey with the mechanosensory lateral line. This species displayed a pause and move search pattern that is consistent with a saltatory search. The pause phase of the search cycle was probably used to detect prey because pauses often ended early in order to initiate an approach at prey and prey were detected throughout the search space. The move phase of the search cycle repositioned the fish so that it moved approximately a third of the reactive distance. Move distance was found to be the most important factor in gaining novel search space. Turning was shown to be relatively unimportant in gaining novel search space with a high frequency of low turn angles made by the fish. The dwarf scorpionfish, however, exhibited a spiralling or looping pattern over a search path exhibiting a turn bias towards either the left or right. The dwarf scorpionfish adopted a search behaviour that is consistent with a saltatory search and efficient for lateral line predation.