scholarly journals Locomotion in sturgeon: function of the pectoral fins

1999 ◽  
Vol 202 (18) ◽  
pp. 2413-2432 ◽  
Author(s):  
C.D. Wilga ◽  
G.V. Lauder
Keyword(s):  
Water Column ◽  
Three Dimensional ◽  
Total Body Length ◽  
The Body ◽  
Force Balance ◽  
Propulsive Force ◽  
Pectoral Fin ◽  
Posterior Portion ◽  
Body Angle ◽  
Pectoral Fins

Pectoral fins are one of the major features of locomotor design in ray-finned fishes and exhibit a well-documented phylogenetic transition from basal to derived clades. In percomorph fishes, the pectoral fins are often used to generate propulsive force via oscillatory movements, and pectoral fin propulsion in this relatively derived clade has been analyzed extensively. However, in the plesiomorphic pectoral fin condition, exemplified by sturgeon, pectoral fins extend laterally from the body in a generally horizontal orientation, have been assumed to generate lift to balance lift forces and moments produced by the heterocercal tail, and are not oscillated to generate propulsive force. The proposal that pectoral fins in fishes such as sturgeon generate lift during horizontal locomotion has never been tested experimentally in freely swimming fishes. In this paper, we examine the function of pectoral fins in sturgeon swimming at speeds from 0.5-3.0 L s(−)(1), where L is total body length. Sturgeon were studied during steady horizontal locomotion as well as while sinking and rising in the water column. Pectoral fin function was quantified using three-dimensional kinematics to measure the orientation of the fin surface, digital particle image velocimetry (DPIV) was used to describe flow in the wake of the fin and to estimate force exerted on the water, and electromyography was used to assess pectoral fin muscle function. Sturgeon (size range 25–32 cm total length) swam horizontally using continuous undulations of the body with a positive body angle that decreased from a mean of 20 degrees at 0.5 L s(−)(1) to 0 degrees at 3.0 L s(−)(1). Both the angle of the body and the pectoral fin surface angle changed significantly when sturgeon moved vertically in the water column. Three-dimensional kinematic analysis showed that during steady horizontal swimming the pectoral fins are oriented with a negative angle of attack predicted to generate no significant lift. This result was confirmed by DPIV analysis of the pectoral fin wake, which only revealed fin vortices, and hence force generation, during maneuvering. The orientation of the pectoral fins estimated by a two-dimensional analysis alone is greatly in error and may have contributed to previous suggestions that the pectoral fins are oriented to generate lift. Combined electromyographic and kinematic data showed that the posterior half of the pectoral fin is actively moved as a flap to reorient the head and body to initiate rising and sinking movements. A new force balance for swimming sturgeon is proposed for steady swimming and vertical maneuvering. During steady locomotion, the pectoral fins generate no lift and the positive body angle to the flow is used both to generate lift and to balance moments around the center of mass. To initiate rising or sinking, the posterior portion of the pectoral fins is actively moved ventrally or dorsally, respectively, initiating a starting vortex that, in turn, induces a pitching moment reorienting the body in the flow. Adjustments to body angle initiated by the pectoral fins serve as the primary means by which moments are balanced.

scholarly journals Three-dimensional kinematics and wake structure of the pectoral fins during locomotion in leopard sharks Triakis semifasciata

2000 ◽  
Vol 203 (15) ◽  
pp. 2261-2278 ◽  
Author(s):  
C.D. Wilga ◽  
G.V. Lauder
Keyword(s):  
Water Column ◽  
Three Dimensional ◽  
The Body ◽  
Force Balance ◽  
Body Tilt ◽  
Pectoral Fin ◽  
Body Angle ◽  
Pectoral Fins ◽  
Triakis Semifasciata ◽  
Leopard Sharks

The classical theory of locomotion in sharks proposes that shark pectoral fins are oriented to generate lift forces that balance the moment produced by the oscillating heterocercal tail. Accordingly, previous studies of shark locomotion have used fixed-wing aircraft as a model assuming that sharks have similar stability and control mechanisms. However, unlike airplanes, sharks are propelled by undulations of the body and tail and have considerable control of pectoral fin motion. In this paper, we use a new approach to examine the function of the pectoral fins of leopard sharks, Triakis semifasciata, during steady horizontal swimming at speeds of 0.5-2.0ls(−1), where l is total body length, and during vertical maneuvering (rising and sinking) in the water column. The planar orientation of the pectoral fin was measured using three-dimensional kinematics, while fluid flow in the wake of the pectoral fin and forces exerted on the water by the fin were quantified using digital particle image velocimetry (DPIV). Steady horizontal swimming in leopard sharks is characterized by continuous undulations of the body with a positive body tilt to the flow that decreases from a mean of 11 degrees to 0.6 degrees with increasing flow speeds from 0. 5 to 2.0ls(−1). Three-dimensional analysis showed that, during steady horizontal locomotion, the pectoral fins are cambered, concave downwards, at a negative angle of attack that we predict to generate no significant lift. Leopard shark pectoral fins are also oriented at a substantial negative dihedral angle that amplifies roll moments and hence promotes rapid changes in body position. Vortices shed from the trailing edge of the pectoral fin were detected only during vertical maneuvering. Starting vortices are produced when the posterior plane of the pectoral fin is actively flipped upwards or downwards to initiate rising or sinking, respectively, in the water column. The starting vortex produced by the pectoral fin induces a pitching moment that reorients the body relative to the flow. Body and pectoral fin surface angle are altered significantly when leopard sharks change vertical position in the water column. Thus, locomotion in leopard sharks is not analogous to flight in fixed-wing aircraft. Instead, a new force balance for swimming leopard sharks is proposed for steady swimming and maneuvering. Total force balance on the body is adjusted by altering the body angle during steady swimming as well as during vertical maneuvering, while the pectoral fins appear to be critical for initiating maneuvering behaviors, but not for lift production during steady horizontal locomotion.

Fluid dynamics of flapping aquatic flight in the bird wrasse:three-dimensional unsteady computations with fin deformation

2002 ◽  
Vol 205 (19) ◽  
pp. 2997-3008 ◽  
Author(s):  
Ravi Ramamurti ◽  
William C. Sandberg ◽  
Rainald Löhner ◽  
Jeffrey A. Walker ◽  
Mark W. Westneat
Keyword(s):  
Fluid Dynamics ◽  
Steady State ◽  
Three Dimensional ◽  
Force Production ◽  
Time History ◽  
The Body ◽  
Vertical Acceleration ◽  
Field Variation ◽  
Pectoral Fin ◽  
Pectoral Fins

SUMMARY Many fishes that swim with the paired pectoral fins use fin-stroke parameters that produce thrust force from lift in a mechanism of underwater flight. These locomotor mechanisms are of interest to behavioral biologists,biomechanics researchers and engineers. In the present study, we performed the first three-dimensional unsteady computations of fish swimming with oscillating and deforming fins. The objective of these computations was to investigate the fluid dynamics of force production associated with the flapping aquatic flight of the bird wrasse Gomphosus varius. For this computational work, we used the geometry of the wrasse and its pectoral fin,and previously measured fin kinematics, as the starting points for computational investigation of three-dimensional (3-D) unsteady fluid dynamics. We performed a 3-D steady computation and a complete set of 3-D quasisteady computations for a range of pectoral fin positions and surface velocities. An unstructured, grid-based, unsteady Navier—Stokes solver with automatic adaptive remeshing was then used to compute the unsteady flow about the wrasse through several complete cycles of pectoral fin oscillation. The shape deformation of the pectoral fin throughout the oscillation was taken from the experimental kinematics. The pressure distribution on the body of the bird wrasse and its pectoral fins was computed and integrated to give body and fin forces which were decomposed into lift and thrust. The velocity field variation on the surface of the wrasse body, on the pectoral fins and in the near-wake was computed throughout the swimming cycle. We compared our computational results for the steady, quasi-steady and unsteady cases with the experimental data on axial and vertical acceleration obtained from the pectoral fin kinematics experiments. These comparisons show that steady state computations are incapable of describing the fluid dynamics of flapping fins. Quasi-steady state computations, with correct incorporation of the experimental kinematics, are useful when determining trends in force production, but do not provide accurate estimates of the magnitudes of the forces produced. By contrast, unsteady computations about the deforming pectoral fins using experimentally measured fin kinematics were found to give excellent agreement, both in the time history of force production throughout the flapping strokes and in the magnitudes of the generated forces.

Quebecius quebecensis (Whiteaves), a porolepiform crossopterygian (Pisces) from the Late Devonian of Quebec, Canada

1987 ◽  
Vol 24 (12) ◽  
pp. 2351-2361 ◽  
Author(s):  
Hans-Peter Schultze ◽  
Marius Arsenault
Keyword(s):  
Ventral Side ◽  
The Body ◽  
Late Devonian ◽  
Pectoral Fin ◽  
Pectoral Fins ◽  
Median Fins ◽  
Pelvic Fin

Quebecius quebecensis (Whiteaves 1889) is a porolepiform crossopterygian related to Glyptolepis. A large nariodal, a large tabular, a separate intertemporal, and a large fused nasosupraorbital are features of Quebecius that characterize it as a porolepiform. The small size of the operculum, median extrascapular larger than the lateral one, small lower squamosals, and deep maxilla are additional features separating Quebecius from Glyptolepis. As in Glyptolepis, the median fins are not lobed. The pectoral fin possesses a long fleshy lobe. The internal, ventral side of the broadly based pelvic fin suggests that the internal axis has shifted towards the body. Pectoral fins with a long fleshy lobe are a common feature of porolepiforms, but lobed bases in the pelvic and unpaired fins are a feature found in Holoptychius, and not in Glyptolepis and Quebecius. Quebecius quebecensis is conspecific with Quebecius williamsi Schultze 1973, mistakenly described as an onychodont crossopterygian.

Swimming behavior of juvenile giant scallop, Placopecten magellanicus, in relation to size and temperature

1991 ◽  
Vol 69 (8) ◽  
pp. 2250-2254 ◽  
Author(s):  
J. L. Manuel ◽  
Michael J. Dadswell
Keyword(s):  
Water Column ◽  
Significant Relationship ◽  
Size Range ◽  
Shell Height ◽  
Swimming Behavior ◽  
The Body ◽  
Placopecten Magellanicus ◽  
Body Angle ◽  
The Mean ◽  
Increasing Temperature

Juvenile scallops (shell height 4–35 mm) were stimulated to swim in an aquarium using a whelk, and their swimming was recorded and analyzed using a videocassette recorder. Scallops ascended in the water column in straight, spiral, or twisting patterns, and the majority never swam horizontally. Two types of swimming were observed. Stable swimming, with a consistent body angle (the angle that the scallop makes with the horizon), was recorded over the size range of scallops examined. In stepwise swimming, the body angle alternated between steep (98 ± 13 (SD)) and more horizontal angles (51 ± 9°). Stepwise swimming was observed among the smaller (mean ± SD = 8 ± 3 mm) scallops. Maximum and mean velocities were positively correlated with both shell height and temperature. Clap rate (Cr) increased with increasing temperature (Cr = 0.29T (°C) + 1.3). Body angle expressed a significant relationship with shell height. Below 10 mm shell height the mean angle was 82°; between 30 and 35 mm the mean angle was 38°.

scholarly journals The ocellate river stingray (Potamotrygon motoro) exploits vortices of sediment to bury into the substrate

2019 ◽  
Author(s):  
S.G. Seamone ◽  
D.A. Syme
Keyword(s):  
Particle Image ◽  
Dorsal Surface ◽  
Ventral Surface ◽  
The Body ◽  
Effective Control ◽  
Posterior Portion ◽  
Dorsal Midline ◽  
Pectoral Fins ◽  
Image Velocimetry ◽  
Sediment Flow

ABSTRACTParticle image velocimetry and video analysis were employed to discern and describe the mechanism used by the stingray Potamotrygon motoro to bury into the substrate. P. motoro repeatedly and rapidly pumped the body up and down while folding the posterior portion of the pectoral fins up and over, drawing water in and suspending sediment beneath the pectoral disc. As the fins folded up and over, vortices of fluidized sediment travelled along the ventral surface of the fins toward the fin tips, and were then directed onto the dorsal surface of the fins and towards the dorsal midline of the fish, where they dissipated and the sediment settled over the dorsal surface of the ray. As displacement and speed of the body pumping and finbeat motions increased, the speed of the sediment translating across the dorsal surface increased, and accordingly, sediment coverage of the dorsal surface increased. Mean sediment coverage was 82.5% ± 3.0 S.E.M, and appeared to be selectively controlled, whereby the pectoral fins tended to bury more than the body, head and tail, and the body more than the head and the tail. In the most vigorous burying events, vortices of sediment shed from each fin collided at the midline and annihilated, reorienting the sediment flow and sending jets of sediment towards the head and the tail, covering these locations with sediment. Hence, this study demonstrates that the mechanism of burying employed by P. motoro permits effective control of sediment vortices and flows to modulate the extent of burying.

Swimming in needlefish (Belonidae): anguilliform locomotion with fins

2002 ◽  
Vol 205 (18) ◽  
pp. 2875-2884 ◽  
Author(s):  
James C. Liao
Keyword(s):  
Surface Waters ◽  
High Speed ◽  
Total Body Length ◽  
The Body ◽  
Pectoral Fins ◽  
Half Wavelength ◽  
Total Body ◽  
Length Analysis ◽  
Median Fins ◽  
Tail Beat

SUMMARYThe Atlantic needlefish (Strongylura marina) is a unique anguilliform swimmer in that it possesses prominent fins, lives in coastal surface-waters, and can propel itself across the surface of the water to escape predators. In a laboratory flow tank, steadily swimming needlefish perform a speed-dependent suite of behaviors while maintaining at least a half wavelength of undulation on the body at all times. To investigate the effects of discrete fins on anguilliform swimming, I used high-speed video to record body and fin kinematics at swimming speeds ranging from 0.25 to 2.0 Ls-1 (where L is the total body length). Analysis of axial kinematics indicates that needlefish are less efficient anguilliform swimmers than eels, indicated by their lower slip values. Body amplitudes increase with swimming speed, but unlike most fishes, tail-beat amplitude increases linearly and does not plateau at maximal swimming speeds. At 2.0 Ls-1, the propulsive wave shortens and decelerates as it travels posteriorly, owing to the prominence of the median fins in the caudal region of the body. Analyses of fin kinematics show that at 1.0 Ls-1 the dorsal and anal fins are slightly less than 180° out of phase with the body and approximately 225° out of phase with the caudal fin. Needlefish exhibit two gait transitions using their pectoral fins. At 0.25 L s-1, the pectoral fins oscillate but do not produce thrust, at 1.0 L s-1 they are held abducted from the body,forming a positive dihedral that may reduce rolling moments, and above 2.0 L s-1 they remain completely adducted.

KINEMATICS OF PECTORAL FIN LOCOMOTION IN THE BLUEGILL SUNFISH LEPOMIS MACROCHIRUS

1994 ◽  
Vol 189 (1) ◽  
pp. 133-161 ◽  
Author(s):  
A Gibb ◽  
B Jayne ◽  
G Lauder
Keyword(s):  
Swimming Speed ◽  
Beat Frequency ◽  
Lepomis Macrochirus ◽  
Force Balance ◽  
Total Force ◽  
Bluegill Sunfish ◽  
Pectoral Fin ◽  
Lateral Projection ◽  
Pectoral Fins ◽  
Distal Edge

The pectoral fins of ray-finned fishes are flexible and capable of complex movements, and yet little is known about the pattern of fin deformation during locomotion. For the most part, pectoral fins have been modeled as rigid plates. In order to examine the movements of different portions of pectoral fins, we quantified the kinematics of pectoral fin locomotion in the bluegill sunfish Lepomis macrochirus using several points on the distal fin edge and examined the effects of swimming speed on fin movements. We simultaneously videotaped the ventral and lateral views of pectoral fins of four fish swimming in a flow tank at five speeds ranging from 0.3 to 1.1 total lengths s-1. Four markers, placed on the distal edge of the fin, facilitated field-by-field analysis of kinematics. We used analyses of variance to test for significant variation with speed and among the different marker positions. Fin beat frequency increased significantly from 1.2 to 2.1 Hz as swimming speed increased from 0.3 to 1.0 total lengths s-1. Maximal velocities of movement for the tip of the fin during abduction and adduction generally increased significantly with increased swimming speed. The ratio of maximal speed of fin retraction to swimming speed declined steadily from 2.75 to 1.00 as swimming speed increased. Rather than the entire distal edge of the fin always moving synchronously, markers had phase lags as large as 32 with respect to the dorsal edge of the fin. The more ventral and proximal portions of the fin edge usually had smaller amplitudes of movement than did the more dorsal and distal locations. With increased swimming speed, the amplitudes of the lateral and longitudinal fin movements generally decreased. We used two distal markers and one basal reference point to determine the orientation of various planar fin elements. During early adduction and most of abduction, these planar fin elements usually had positive angles of attack. Because of fin rotation, angles of attack calculated from three-dimensional data differed considerably from those estimated from a simple lateral projection. As swimming speed increased, the angles of attack of the planar fin elements with respect to the overall direction of swimming approached zero. The oscillatory movements of the pectoral fins of bluegill suggest that both lift- and drag-based propulsive mechanisms are used to generate forward thrust. In addition, the reduced frequency parameter calculated for the pectoral fin of Lepomis (sigma=0.85) and the Reynolds number of 5x10(3) indicate that acceleration reaction forces may contribute significantly to thrust production and to the total force balance on the fin.

scholarly journals Biomechanics of Frog Swimming: I. Estimation of the Propulsive Force Generated by Hymenochirus Boettgeri

1988 ◽  
Vol 138 (1) ◽  
pp. 399-411 ◽  
Author(s):  
JULIANNA M. GAL ◽  
R. W. BLAKE
Keyword(s):  
Recovery Phase ◽  
Added Mass ◽  
The Body ◽  
Force Balance ◽  
Upper And Lower Bounds ◽  
Power Stroke ◽  
Propulsive Force ◽  
Body Velocity ◽  
Hymenochirus Boettgeri ◽  
Single Sequence

Ciné films were used to study swimming in the frog, Hymenochirus boettgeri (Tornier) during near-vertical breathing excursions. The animals generally decelerated during hindlimb flexion (recovery phase) and accelerated throughout hindlimb extension (power phase). Body velocity patterns of frogs are distinct from those of other drag-based paddlers, such as angelfish and water boatman, where the body is accelerated and decelerated within the power stroke phase. The propulsive force, estimated for a single sequence from quasi-steady drag and inertial considerations, was positive throughout extension. The upper and lower bounds of this estimate were calculated by considering additional components of the force balance, including the net effect of gravity and buoyancy, and the longitudinal added mass forces associated with the body. Consideration of the force balance implies that simple drag-based propulsion may not be sufficient to explain the swimming patterns observed in frogs.

The Motion of Euglena Viridis: The Role of Flagella

1966 ◽  
Vol 44 (3) ◽  
pp. 579-588 ◽  
Author(s):  
M. E. J. HOLWILL
Keyword(s):  
Theoretical Analysis ◽  
High Speed ◽  
Body Movement ◽  
Three Dimensional ◽  
The Body ◽  
Propulsive Force

1. Analysis of high-speed cine-films of Euglena viridis reveal that the organism traverses a complex three-dimensional path while helical waves are propagated from base to tip along the flagellum. 2. Theoretical analysis shows that the rapid forward velocity of the organism cannot be produced by the body movement alone. The propulsive force generated by the flagellum is sufficient to maintain the observed velocities. 3. Although the euglenoid flagellum bears mastigonemes the thrust produced by it is in the direction to be expected if the flagellum were smooth. Possible explanations of this observation are given.

scholarly journals Station-Holding by three Species of Benthic Fishes

1989 ◽  
Vol 145 (1) ◽  
pp. 303-320 ◽  
Author(s):  
PAUL W. WEBB
Keyword(s):  
Friction Coefficient ◽  
Smooth Surface ◽  
The Body ◽  
Published Data ◽  
High Lift ◽  
Posterior Portion ◽  
Drag Coefficients ◽  
Pectoral Fins ◽  
Benthic Fishes ◽  
Median Fins

Station-holding performance was determined on a smooth substratum and on a grid substratum for three species of benthic fishes differing in body shape, surface texture, density, friction coefficient and behavioural repertoire. The grid was made of wires parallel to the flow, which raised fish into the free stream. Limited observations were also made on the benthopelagic cod. Station-holding performance was evaluated at two speeds. The first was defined as the slip speed, above which activities such as swimming, fin-beating, body arching, body clamping and gripping the substratum were required to hold position on the substratum. The second was defined as the swim speed, when fish began swimming out of ground contact. Cod and lasher started swimming when they began slipping, so that slip and swim speeds were the same, averaging 6cms−1 for cod and 32cms−1 for lasher on the smooth surface. Body postures and fin-beating delayed swimming from a slip speed of about 20cms−1 to swim speeds of 47–58cms−1 for plaice and rays. The grid had relatively little effect on slip and swim speeds of plaice and rays. Lasher grasped the grid with their pectoral fins, increasing swim speeds to 55cms−1. Amputation of the posterior portion of the median fins of plaice reduced swim speeds on the smooth surface to 36cms−1. Amputation of the pectoral fins of lasher reduced the swim speed on the grid to 38cms−1. Estimates of drag coefficients for fish were made using published data for blisters. These were used to determine lift coefficients and the effects of grasping the substratum on the friction coefficient. Comparison of lift coefficients of rays on the smooth substratum with those on the grid showed that flow beneath the body reduced lift. Amputation of the posterior of the median fins of plaice and the rarity of body posturing by plaice and rays on the grid showed that the major role of this station-holding behaviour was reduction of lift through induction of flow beneath the body. Lashers were able to hold station at speeds comparable to plaice and rays when they could utilize the small amount of surface structure of the grid to increase friction. Benthic fishes tend to have either ‘flattened’ plaice- or ray-like forms with low drag coefficients but high lift coefficients, or more fusiform lasher-like forms with high drag coefficients and low lift coefficients. High-lift forms use behaviour to reduce lift coefficients, whereas high-drag forms use behaviour to increase friction.

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