Sensory integration in the hydrodynamic world of rainbow trout

Abstract

Water movements, of both abiotic and biotic origin, provide a wealth of information for fishes. They detect these water movements by arrays of hydrodynamic sensors located on the surface of the body as superficial neuromasts and embedded in subdermal lateral line canals. Recently, the anatomical dichotomy between superficial and canal neuromasts has been matched by demonstrations of a corresponding functional dichotomy. Superficial neuromasts are sensitive to water flows over the surface of the fish and are the sub-modality that participates in orientation to water currents, a behaviour known as rheotaxis. The canal neuromasts are sensitive to water vibration and it is this sub-modality that determines the localization of artificial prey. Recently, however, it has been shown that the complex behaviour of natural prey capture in the dark requires input from both lateral line sensory submodalities and here we show that the ability of trout to hold station behind a stationary object in fast flowing water also requires integration of information from both sub-modalities.

The spatiotemporal dynamics of rheotactic behavior depends on flow speed and available sensory information

“…In this study, fish with vision were able to maintain their streamwise position for up to 3min (maximum test period) at different locations along the upstream/downstream axis of the tank (red functions in Fig.9E) and without reference to any upstream bluff body, as previously reported for obstacle-entrainment behaviors (Sutterlin and Waddy, 1975;Montgomery et al, 2003;Liao et al, 2003;Przybilla et al, 2010). Visual, tactile and/or lateral line senses can all theoretically inform fish about their body position with respect to some external spatial reference.…”

“…Thus, when deprived of visual cues, midwater fish may need to alter their behavior so that they are periodically in contact with the substrate to provide a (tactile) external frame of reference, as suggested previously (Lyon, 1904;Baker and Montgomery, 1999a). The effect of these fundamental differences in sensory input on behavioral output remains largely undocumented, except in the context of obstacle entrainment behaviors (Sutterlin and Waddy, 1975;Liao et al, 2003;Montgomery et al, 2003;Przybilla et al, 2010), which have a rheotactic component.…”

Fish can encode order in their spatial map

“…The resulting change in the flow field around the fish is detected by superficial lateral line neuromasts (Montgomery et al 2003). The cave fish respond to perceived changes in their environment by temporarily accelerating which extends the bow wave and hence the near-field range of the lateral line system.…”

Entraining in trout: a behavioural and hydrodynamic analysis

“…Fig.1A, Fig.2). Trout use the water motions caused by the cylinder not only for Kármán gaiting (Liao, 2004;Liao, 2006;Liao et al, 2003a;Liao et al, 2003b) but also for entraining (Liao, 2006;Montgomery et al, 2003;Sutterlin and Waddy, 1975;Webb, 1998) and swimming in the bow wake (Liao et al, 2003a).…”