scholarly journals Hydrodynamics of prey capture in sharks: effects of substrate

2006 ◽  
Vol 4 (13) ◽  
pp. 341-345 ◽  
Author(s):  
Sandra Nauwelaerts ◽  
Cheryl Wilga ◽  
Christopher Sanford ◽  
George Lauder
Keyword(s):  
Prey Capture ◽  
Theoretical Modelling ◽  
Head Model ◽  
Suction Feeding ◽  
Chiloscyllium Plagiosum ◽  
Fluid Velocities ◽  
Image Velocimetry ◽  
Stream Functions ◽  
Mouth Width ◽  
Dynamics Modelling

In suction feeding, a volume of water is drawn into the mouth of a predator. Previous studies of suction feeding in fishes have shown that significant fluid velocities are confined to a region within one mouth width from the mouth. Therefore, the predator must be relatively close to the prey to ensure capture success. Here, theoretical modelling is combined with empirical data to unravel the mechanism behind feeding on a substrate. First, we approached the problem theoretically by combining the stream functions of two sinks. Computational fluid dynamics modelling is then applied to make quantitative predictions regarding the effects of substrate proximity on the feeding hydrodynamics of a benthic shark. An oblique circular cylinder and a shark head model were used. To test the models, we used digital particle image velocimetry to record fluid flow around the mouth of white-spotted bamboo sharks, Chiloscyllium plagiosum , during suction feeding on the substrate and in the water column. Empirical results confirmed the modelling predictions: the length of the flow field can be doubled due to passive substrate effects during prey capture. Feeding near a substrate extends the distance over which suction is effective and a predator strike can be effective further from the prey.

scholarly journals Relative importance of growth and behaviour to elasmobranch suction-feeding performance over early ontogeny

2007 ◽  
Vol 5 (23) ◽  
pp. 641-652 ◽  
Author(s):  
Dayv Lowry ◽  
Philip J Motta
Keyword(s):  
Prey Capture ◽  
Volume Growth ◽  
Early Ontogeny ◽  
Maximum Pressure ◽  
Suction Feeding ◽  
Size Dependent ◽  
Chiloscyllium Plagiosum ◽  
Dietary Shifts ◽  
Triakis Semifasciata ◽  
Leopard Sharks

Development of the ability to capture prey is crucial to predator survival. Trends in food-capture performance over early ontogeny were quantified for leopard sharks Triakis semifasciata and whitespotted bamboosharks Chiloscyllium plagiosum by measuring suction pressure and flow in front of the mouth during feeding. At any size, C. plagiosum produce greater subambient pressure and ingest more rounded water parcels. Maximum subambient pressure scaled with negative allometry in T. semifasciata and was accompanied by an increase in the time to reach maximum gape. Despite a similar trend in buccal expansion timing, maximum pressure in C. plagiosum scaled with isometry and was accompanied by an earlier onset of hyoid depression and a positive allometric increase in buccal reserve volume. Growth was the primary factor responsible for developmental trends in both species, with size-independent behavioural changes contributing little to overall performance variability. Ontogenetic dietary shifts are predicted for both species as a consequence of size-dependent changes in performance. Chiloscyllium plagiosum becomes anatomically and behaviourally canalized towards suction feeding, limiting the effective range of prey capture and possibly necessitating stalking. Triakis semifasciata , by contrast, retains the flexibility to employ both ram and suction and therefore captures more elusive prey with age.

scholarly journals The benefits of planar circular mouths on suction feeding performance

2012 ◽  
Vol 9 (73) ◽  
pp. 1767-1773 ◽  
Author(s):  
Tyler Skorczewski ◽  
Angela Cheer ◽  
Peter C. Wainwright
Keyword(s):  
Prey Capture ◽  
Peak Flow ◽  
Mouth Opening ◽  
Suction Feeding ◽  
Flow Rates ◽  
Computational Fluid Dynamics Simulations ◽  
Enhance Efficiency ◽  
And Performance ◽  
Dynamics Simulations ◽  
Hydrodynamic Effects

Suction feeding is the most common form of prey capture across aquatic feeding vertebrates and many adaptations that enhance efficiency and performance are expected. Many suction feeders have mechanisms that allow the mouth to form a planar and near-circular opening that is believed to have beneficial hydrodynamic effects. We explore the effects of the flattened and circular mouth opening through computational fluid dynamics simulations that allow comparisons with other mouth profiles. Compared to mouths with lateral notches, we find that the planar mouth opening results in higher flow rates into the mouth and a region of highest flow that is positioned at the centre of the mouth aperture. Planar mouths provide not only for better total fluid flow rates through the mouth but also through the centre of the mouth near where suction feeders position their prey. Circular mouths are shown to provide the quickest capture times for spherical and elliptical prey because they expose the prey item to a large region of high flow. Planar and circular mouths result in higher flow velocities with peak flow located at the centre of the mouth opening and they maximize the capacity of the suction feeders to exert hydrodynamic forces on the prey.

Evaluating the use of ram and suction during prey capture by cichlid fishes

2001 ◽  
Vol 204 (17) ◽  
pp. 3039-3051 ◽  
Author(s):  
Peter C. Wainwright ◽  
Lara A. Ferry-Graham ◽  
Thomas B. Waltzek ◽  
Andrew M. Carroll ◽  
C. Darrin Hulsey ◽  
...  
Keyword(s):  
Poecilia Reticulata ◽  
Prey Capture ◽  
Suction Feeding ◽  
Predator Species ◽  
Cichlid Fishes ◽  
Major Constraint ◽  
Exponential Decline ◽  
Astronotus Ocellatus ◽  
Limited Variation ◽  
Jaw Protrusion

SUMMARYWe characterized prey-capture strategies in seven species of cichlid fishes representing diverse trophic habits and anticipated feeding abilities. The species examined were Petenia splendida, Cichla ocellaris, Cichlasoma minckleyi, Astronotus ocellatus, Crenicichla geayi, Heros severus (formerly Cichlasoma severum) and Cyprichromis leptosoma. Three individuals per species were filmed with video at 500Hz as they captured live adult Artemia sp. and Poecilia reticulata. For each feeding sequence, we measured the contribution of predator movement towards the prey (i.e. ram) and the movement of prey towards the predator due to suction. The use of ram differed significantly among prey types and predator species, varying as much as sixfold across predator species. High values of ram resulted in high attack velocities. Jaw protrusion contributed as much as 50% to overall ram values in some species, verifying its role in enhancing attack velocity. Suction distance did not vary significantly among species. Diversity in prey-capture behavior was therefore found to reflect differences among species in the strategy used to approach prey. Limited variation in the distance from which prey were sucked into the mouth is interpreted as the result of an expected exponential decline in water velocity with distance from the mouth of the suction-feeding predator. We propose that this relationship represents a major constraint on the distance over which suction feeding is effective for all aquatic-feeding predators.

scholarly journals Volumetric quantification of fluid flow reveals fish's use of hydrodynamic stealth to capture evasive prey

2014 ◽  
Vol 11 (90) ◽  
pp. 20130880 ◽  
Author(s):  
Brad J. Gemmell ◽  
Deepak Adhikari ◽  
Ellen K. Longmire
Keyword(s):  
High Speed ◽  
Prey Capture ◽  
Fluid Motion ◽  
Three Dimensional ◽  
Trophic Levels ◽  
Small Fish ◽  
Major Pathway ◽  
Image Velocimetry ◽  
Highly Sensitive ◽  
Volumetric Quantification

In aquatic ecosystems, predation on zooplankton by fish provides a major pathway for the transfer of energy to higher trophic levels. Copepods are an abundant zooplankton group that sense hydromechanical disturbances produced by approaching predators and respond with rapid escapes. Despite this capability, fish capture copepods with high success. Previous studies have focused on the predatory strike to elucidate details of this interaction. However, these raptorial strikes and resulting suction are only effective at short range. Thus, small fish must closely approach highly sensitive prey without triggering an escape in order for a strike to be successful. We use a new method, high-speed, infrared, tomographic particle image velocimetry, to investigate three-dimensional fluid patterns around predator and prey during approaches. Our results show that at least one planktivorous fish ( Danio rerio ) can control the bow wave in front of the head during the approach and consumption of prey (copepod). This alters hydrodynamic profiles at the location of the copepod such that it is below the threshold required to elicit an escape response. We find this behaviour to be mediated by the generation of suction within the buccopharyngeal cavity, where the velocity into the mouth roughly matches the forward speed of the fish. These results provide insight into how animals modulate aspects of fluid motion around their bodies to overcome escape responses and enhance prey capture.

scholarly journals A complex performance landscape for suction-feeding reveals constraints and adaptations in a population of reef damselfish

2017 ◽  
Author(s):  
Tal Keren ◽  
Moshe Kiflawi ◽  
Christopher H Martin ◽  
Victor China ◽  
Ofri Mann ◽  
...  
Keyword(s):  
Morphological Traits ◽  
Prey Capture ◽  
Mechanistic Model ◽  
Adaptive Landscape ◽  
Phenotypic Traits ◽  
Stabilizing Selection ◽  
Suction Feeding ◽  
Feeding Performance ◽  
Genetic Constraints ◽  
A Performance

AbstractThe ability to predict how multiple traits interact in determining performance is key to understanding the evolution of complex functional systems. Similar to Simpson’s adaptive landscape, which describes the fitness consequences of varying morphological traits, performance landscapes depict the performance consequences of varying morphological traits. Mapping the population’s location with respect to the topographic features of the landscape could inform us on the selective forces operating on the traits that underlie performance. Here, we used a mechanistic model derived from first principles of hydrodynamics to construct a hypothetical performance landscape for zooplankton prey capture using suction feeding. We then used the landscape to test whether a population of Chromis viridis, a coral reef zooplanktivore, is located on a performance peak or ridge based on measurements of kinematic variables recorded in-situ during undisturbed foraging. Observed trait combinations in the wild population closely matched regions of high feeding performance in the landscape, however the population was not located on a local performance peak. This sub-optimal performance was not due to constraints stemming from the observed trait correlations. The predominant directions of variation of the phenotypic traits was tangent to the ‘path of steepest ascent’ that points towards the local peak, indicating that the population does not reside on a “performance ridge”. Rather, our analysis suggests that feeding performance is constrained by stabilizing selection, possibly reflecting a balance between selection on feeding performance and mechanical or genetic constraints.

scholarly journals Hydrodynamic regime drives flow reversals in suction feeding larval fishes during early ontogeny

2019 ◽  
Author(s):  
Krishnamoorthy Krishnan ◽  
Asif Shahriar Nafi ◽  
Roi Gurka ◽  
Roi Holzman
Keyword(s):  
Numerical Simulations ◽  
High Speed ◽  
Prey Capture ◽  
Sparus Aurata ◽  
Larval Fish ◽  
Fish Larvae ◽  
Numerical Models ◽  
Hydrodynamic Regime ◽  
Suction Feeding ◽  
Larval Fishes

AbstractFish larvae are the smallest self-sustaining vertebrates. As such, they face multiple challenge that stem from their minute size, and from the hydrodynamic regime in which they dwell. This regime of intermediate Reynolds numbers (Re) was shown to affect the swimming of larval fish and impede their ability to capture prey. Numerical simulations indicate that the flow fields external to the mouth in younger larvae result in shallower spatial gradients, limiting the force exerted on the prey. However, observations on feeding larvae suggest that failures in prey capture can also occur during prey transport, although the mechanism causing these failures is unclear. We combine high-speed videography and numerical simulations to investigate the hydrodynamic mechanisms that impede prey transport in larval fishes. Detailed kinematics of the expanding mouth during prey capture by larval Sparus aurata were used to parameterize age-specific numerical models of the flows inside the mouth. These models reveal that, for small larvae that slowly expand their mouth, not all the fluid that enters the mouth cavity is expelled through the gills, resulting in flow reversal at the mouth orifice. This efflux at the mouth orifice was highest in the younger ages, but was also high (>8%) in slow strikes produced by larger fish. Our modeling explains the observations of “in-and-out” events in larval fish, where prey enters the mouth but is not swallowed. It further highlights the importance of prey transport as an integral part in determining suction feeding success.

scholarly journals Prey Capture Hydrodynamics in Fishes: Experimental Tests of Two Models

1983 ◽  
Vol 104 (1) ◽  
pp. 1-13 ◽  
Author(s):  
GEORGE V. LAUDER
Keyword(s):  
High Speed ◽  
Prey Capture ◽  
Regression Line ◽  
Lepomis Macrochirus ◽  
Experimental Tests ◽  
Relative Magnitude ◽  
Suction Feeding ◽  
Mouth Cavity ◽  
Large Pressure ◽  
Key Aspects

Three experimental modifications of the feeding mechanism in the bluegill sunfish (Lepomis macrochirus Rafinesque: Centrarchidae) were performed to distinguish between two alternative hydrodynamic models of the high-speed suction-feeding process in fishes. These two models make different predictions about the change in slope of the regression line representing the relationship between buccal and opercular cavity pressures, and the three experiments provide a critical test of the models. The results from all three tests unequivocally support (1) the concept of the gill bars as a resistant element within the mouth cavity functionally dividing it into buccal and opercular cavities, (2) the negligible role of lateral movement of the gill cover (operculum) in generating negative mouth cavity pressures, and (3) the large pressure differentials previously reported between the buccal and opercular cavities. Measured pressures conform neither in relative magnitude nor waveform with pressures predicted from theoretical mathematical models. Inertial effects and accelerational flows are key aspects of high-speed suction feeding.

scholarly journals Biomechanics and hydrodynamics of prey capture in the Chinese giant salamander reveal a high-performance jaw-powered suction feeding mechanism

2013 ◽  
Vol 10 (82) ◽  
pp. 20121028 ◽  
Author(s):  
Egon Heiss ◽  
Nikolay Natchev ◽  
Michaela Gumpenberger ◽  
Anton Weissenbacher ◽  
Sam Van Wassenbergh
Keyword(s):  
High Speed ◽  
High Performance ◽  
Prey Capture ◽  
Three Dimensional ◽  
Cranial Morphology ◽  
Suction Feeding ◽  
Mechanical Constraints ◽  
Terrestrial Life ◽  
Chinese Giant Salamander ◽  
Dynamics Simulations

During the evolutionary transition from fish to tetrapods, a shift from uni- to bidirectional suction feeding systems followed a reduction in the gill apparatus. Such a shift can still be observed during metamorphosis of salamanders, although many adult salamanders retain their aquatic lifestyle and feed by high-performance suction. Unfortunately, little is known about the interplay between jaws and hyobranchial motions to generate bidirectional suction flows. Here, we study the cranial morphology, as well as kinematic and hydrodynamic aspects related to prey capture in the Chinese giant salamander ( Andrias davidianus ). Compared with fish and previously studied amphibians, A. davidianus uses an alternative suction mechanism that mainly relies on accelerating water by separating the ‘plates’ formed by the long and broad upper and lower jaw surfaces. Computational fluid dynamics simulations, based on three-dimensional morphology and kinematical data from high-speed videos, indicate that the viscerocranial elements mainly serve to accommodate the water that was given a sufficient anterior-to-posterior impulse beforehand by powerful jaw separation. We hypothesize that this modified way of generating suction is primitive for salamanders, and that this behaviour could have played an important role in the evolution of terrestrial life in vertebrates by releasing mechanical constraints on the hyobranchial system.

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