Sensory performance of blind mexican cave fish after destruction of the canal neuromasts

SUMMARY This paper presents the first computational fluid dynamics (CFD)simulations of viscous flow due to a small sphere vibrating near a fish, a configuration that is frequently used for experiments on dipole source localization by the lateral line. Both two-dimensional (2-D) and three-dimensional (3-D) meshes were constructed, reproducing a previously published account of a mottled sculpin approaching an artificial prey. Both the fish-body geometry and the sphere vibration were explicitly included in the simulations. For comparison purposes, calculations using potential flow theory (PFT) of a 3-D dipole without a fish body being present were also performed. Comparisons between the 2-D and 3-D CFD simulations showed that the 2-D calculations did not accurately represent the 3-D flow and therefore did not produce realistic results. The 3-D CFD simulations showed that the presence of the fish body perturbed the dipole source pressure field near the fish body, an effect that was obviously absent in the PFT calculations of the dipole alone. In spite of this discrepancy, the pressure-gradient patterns to the lateral line system calculated from 3-D CFD simulations and PFT were similar. Conversely, the velocity field, which acted on the superficial neuromasts (SNs), was altered by the oscillatory boundary layer that formed at the fish's skin due to the flow produced by the vibrating sphere (accounted for in CFD but not PFT). An analytical solution of an oscillatory boundary layer above a flat plate, which was validated with CFD, was used to represent the flow near the fish's skin and to calculate the detection thresholds of the SNs in terms of flow velocity and strain rate. These calculations show that the boundary layer effects can be important, especially when the height of the cupula is less than the oscillatory boundary layer's Stokes viscous length scale.

Section: The Journal Of Experimental Biologymentioning

confidence: 47%

Section: Applying the Oscillatory Boundary Layer Solution To Real Expmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Using computational fluid dynamics to calculate the stimulus to the lateral line of a fish in still water

Rapo

Jiang

Grosenbaugh

et al. 2009

“…The biological significance of lateral line systems, however, can only be recognised by studying the behaviour in its natural context (Bleckmann, 1993). The lateral line system has been shown to be involved in many different behaviours such as detection and localisation of stationary objects (Abdel-Latif et al, 1990), obstacle entrainment and rheotaxis in fast-flowing streams (Baker and Montgomery, 1999;Montgomery et al, , 2003Sutterlin and Waddy, 1975) and intraspecific communication such as schooling (Partridge and Pitcher, 1980;Pitcher et al, 1976) and mating (Satou et al, 1993(Satou et al, , 1994. Lateral line involvement was also shown in different feeding behaviours of fish.…”

Section: Discussionmentioning

confidence: 99%

The importance of the lateral line in nocturnal predation of piscivorous catfish

Pohlmann

Atema

Breithaupt

2004

155

108

In a previous study we showed that nocturnal piscivorous catfish track the wake left by a swimming prey fish to locate it, following past locations to detect the present location of the prey. In a wake there are hydrodynamic as well as chemical signatures that both contain information on location and suitability of the prey. In order to determine how these two wake stimuli are utilised in prey tracking, we conducted experiments in catfish in which either the lateral line or the external gustation was ablated. We found that a functional lateral line is indispensable for following the wake of swimming prey. The frequency of attack and capture was greatly diminished and the attacks that did occur were considerably delayed when the lateral line was ablated. In contrast, catfish with ablated external taste still followed the wakes of their prey prior to attacking, albeit their attacks were delayed. The external taste sense, which was reported earlier to be necessary for finding stationary (dead) food, seems to play a minor role in the localisation of moving prey. Our finding suggests that an important function of the lateral line is to mediate wake-tracking in predatory fish.

“…Superficial neuromasts measure the velocity of the flow very close to the skin, while canal neuromasts measure the water pressure difference between adjacent pores in the canal (Denton and Gray, 1983;Denton and Gray, 1988;Denton and Gray, 1989;Denton and Gray, 1982;Kroese and Schellart, 1992). Although surface and canal neuromasts have overlapping functions, blind cave fish can still locate objects even with disabled surface neuromasts (Montgomery et al, 2001), whereas the ability of these fish to navigate with disabled canal neuromasts is impaired or even lost (Abdel-Latif et al, 1990). The pressure difference δp between two adjacent pores of the lateral line is generally considered as a hydrodynamic signal, which also varies with the distance to a wall h (Windsor et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Mexican blind cavefish use mouth suction to detect obstacles

Holzman

Perkol-Finkel

Zilman

2014

Fish commonly use their lateral line system to detect moving bodies such as prey and predators. A remarkable case is the Mexican blind cavefish Astyanax fasciatus, which evolved the ability to detect nonmoving obstacles. The swimming body of A. fasciatus generates fluid disturbances, the alteration of which by an obstacle can be sensed by the fish's lateral line system. It is generally accepted that these alterations can provide information on the distance to the obstacle. We observed that A. fasciatus swimming in an unfamiliar environment open and close their mouths at high frequency (0.7-4.5 Hz) in order to generate suction flows. We hypothesized that repeated mouth suction generates a hydrodynamic velocity field, which is altered by an obstacle, inducing pressure gradients in the neuromasts of the lateral line and corresponding strong lateral line stimuli. We observed that the frequency and rate of mouth-opening events varied with the fish's distance to obstacles, a hallmark of pulse-based navigation mechanisms such as echolocation. We formulated a mathematical model of this hitherto unrecognized mechanism of obstacle detection and parameterized it experimentally. This model suggests that suction flows induce lateral line stimuli that are weakly dependent on the fish's speed, and may be an order of magnitude stronger than the correspondent stimuli induced by the fish's gliding body. We illustrate that A. fasciatus can navigate non-visually using a combination of two deeply ancestral and highly conserved mechanisms of ray-finned fishes: the mechanism of sensing water motion by the lateral line system and the mechanism of generating water motion by mouth suction.