Pectoral fin locomotion in batoid fishes: undulation versus oscillation

2001 ◽  
Vol 204 (2) ◽  
pp. 379-394 ◽  
Author(s):  
L.J. Rosenberger

This study explores the dichotomy between undulatory (passing multiple waves down the fin or body) and oscillatory (flapping) locomotion by comparing the kinematics of pectoral fin locomotion in eight species of batoids (Dasyatis americana, D. sabina, D. say, D. violacea, Gymnura micrura, Raja eglanteria, Rhinobatos lentiginosus and Rhinoptera bonasus) that differ in their swimming behavior, phylogenetic position and lifestyle. The goals of this study are to describe and compare the pectoral fin locomotor behavior of the eight batoid species, to clarify how fin movements change with swimming speed for each species and to analyze critically the undulation/oscillation continuum proposed by Breder using batoids as an example. Kinematic data were recorded for each species over a range of swimming velocities (1–3 disc lengths s(−1)). The eight species in this study vary greatly in their swimming modes. Rhinobatos lentiginosus uses a combination of axial-based and pectoral-fin-based undulation to move forward through the water, with primary thrust generated by the tail. The pectoral fins are activated in short undulatory bursts for increasing swimming speed and for maneuvering. Raja eglanteria uses a combination of pectoral and pelvic locomotion, although only pectoral locomotion is analyzed here. The other six species use pectoral locomotion exclusively to propel themselves through the water. Dasyatis sabina and D. say have the most undulatory fins with an average of 1.3 waves per fin length, whereas Rhinoptera bonasus has the most oscillatory fin behavior with 0.4 waves per fin length. The remaining species range between these two extremes in the degree of undulation present on their fins. There is an apparent trade-off between fin-beat frequency and amplitude. Rhinoptera bonasus has the lowest frequency and the highest fin amplitude, whereas Rhinobatos lentiginosus has the highest frequency and the lowest amplitude among the eight species examined. The kinematic variables that batoids modify to change swimming velocity vary among different species. Rhinobatos lentiginosus increases its tail-beat frequency to increase swimming speed. In contrast, the four Dasyatis species increase swimming speed by increasing frequency and wavespeed, although D. americana also changes wave number. Raja eglanteria modifies its swimming velocity by changing wavespeed and wave number. Rhinoptera bonasus increases wavespeed, Gymnura micrura decreases wave number, and both Rhinoptera bonasus and Gymnura micrura increase fin-tip velocity to increase swimming velocity. Batoid species fall onto a continuum between undulation and oscillation on the basis of the number of waves present on the fins.

1994 ◽  
Vol 189 (1) ◽  
pp. 133-161 ◽  
Author(s):  
A Gibb ◽  
B Jayne ◽  
G Lauder

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.


1996 ◽  
Vol 199 (10) ◽  
pp. 2243-2252 ◽  
Author(s):  
E Drucker ◽  
J Jensen

In this study, we report the first allometric equations relating gait parameters and swimming speed to body size for fish employing pectoral fin locomotion. Comparisons of locomotor kinematics and performance among striped surfperch (Teleostei: Embiotocidae) are made at the pectoral­caudal gait transition speed (Up-c). Up-c is considered to elicit physiologically equivalent levels of exercise in animals varying over 100-fold in body mass (Mb) by virtue of dynamically similar pectoral fin movements (constant duty factor, length-specific stride length and fin-beat amplitude) and size-independent propulsive efficiency. At Up-c, pectoral fin-beat frequency scales in proportion to Mb-0.12±0.03, a size-dependence consistent with that observed for stride frequency in fishes swimming by axial undulatory propulsion and in many running tetrapods. It is proposed that the similarity in the scaling of frequency in these vertebrate groups reflects an underlying similarity in the allometry of the maximal velocity of muscle shortening. Absolute Up-c (m s-1) generally increases with body size, but the fastest speeds are not exhibited by the largest animals. A pattern of declining performance in fish 23 cm in standard length and longer may be related to their disproportionately small fin areas and aspect ratios. The pronounced negative allometry of Up-c expressed as standard body lengths per second indicates that a given length-specific speed does not induce comparable levels of activity in large and small fish. Thus, normalization of swimming speed to body length may not be a sufficient correction for kinematic comparisons across size.


1996 ◽  
Vol 199 (10) ◽  
pp. 2235-2242 ◽  
Author(s):  
E Drucker ◽  
J Jensen

Swimming trials at increasing velocity were used to determine the effects of steady swimming speed on pectoral fin kinematics for an ontogenetic series of striped surfperch Embiotoca lateralis, ranging from 6 to 23 cm in standard length (SL). The fin stroke cycle consisted of a propulsive period, the duration of fin abduction and adduction, and a 'refractory' period, during which the fin remained adducted against the body. Pectoral fin-beat frequency (fp) measured as the inverse of the entire stride period, as in past studies, increased curvilinearly with speed. Frequency, calculated as the reciprocal of the propulsive period alone, increased linearly with speed, as shown previously for tail-beat frequency of fishes employing axial undulation. Fin-beat amplitude, measured as the vertical excursion of the pectoral fin tip during abduction, increased over a limited range of low speeds before reaching a plateau at 0.35­0.40 SL. Pectoral fin locomotion was supplemented by intermittent caudal fin undulation as swimming speed increased. At the pectoral­caudal gait transition speed (Up-c), frequency and amplitude attained maxima, suggesting that the fin musculature reached a physiological limit. The effects of body size on swimming kinematics differed according to the method used for expressing speed. At a given absolute speed, small fish used higher stride frequencies and increased frequency at a faster rate than large fish. In contrast, the relationship between fp and length-specific speed (SL s-1) had a greater slope for large fish and crossed that for small fish at high speeds. We recommend that comparisons across size be made using speeds expressed as a percentage of Up-c, at which kinematic variables influencing thrust are size-independent.


2016 ◽  
Vol 7 (1) ◽  
pp. 198-204 ◽  
Author(s):  
David Deslauriers ◽  
Ryan Johnston ◽  
Steven R. Chipps

Abstract We assessed the effect of fin-curl on the swimming and station-holding ability of juvenile shovelnose sturgeon Scaphirhynchus platorynchus (mean fork length = 17 cm; mean weight = 16 g; n = 21) using a critical swimming speed test performed in a small swim chamber (90 L) at 20°C. We quantified fin-curl severity using the pectoral fin index. Results showed a positive relationship between pectoral fin index and critical swimming speed indicative of reduced swimming performance displayed by fish afflicted with a pectoral fin index < 8%. Fin-curl severity, however, did not affect the station-holding ability of individual fish. Rather, fish affected with severe fin-curl were likely unable to use their pectoral fins to position their body adequately in the water column, which led to the early onset of fatigue. Results generated from this study should serve as an important consideration for future stocking practices.


Robotica ◽  
2019 ◽  
Vol 38 (4) ◽  
pp. 699-718 ◽  
Author(s):  
Van Anh Pham ◽  
Tan Tien Nguyen ◽  
Byung Ryong Lee ◽  
Tuong Quan Vo

SUMMARYBiological fish can create high forward swimming speed due to change of thrust/drag area of pectoral fins between power stroke and recovery stroke in rowing mode. In this paper, we proposed a novel type of folding pectoral fins for the fish robot, which provides a simple approach in generating effective thrust only through one degree of freedom of fin actuator. Its structure consists of two elemental fin panels for each pectoral fin that connects to a hinge base through the flexible joints. The Morison force model is adopted to discover the relationship of the dynamic interaction between fin panels and surrounding fluid. An experimental platform for the robot motion using the pectoral fin with different flexible joints was built to validate the proposed design. The results express that the performance of swimming velocity and turning radius of the robot are enhanced effectively. The forward swimming velocity can reach 0.231 m/s (0.58 BL/s) at the frequency near 0.75 Hz. By comparison, we found an accord between the proposed dynamic model and the experimental behavior of the robot. The attained results can be used to design controllers and optimize performances of the robot propelled by the folding pectoral fins.


1973 ◽  
Vol 59 (3) ◽  
pp. 697-710 ◽  
Author(s):  
P. W. WEBB

1. The kinematics of pectoral-fin propulsion have been measured for Cymatogaster aggregata, 14·3 cm in length, during an increasing-velocity performance test. Acclimation and test temperature was 15 °C, similar to the fishes' normal environmental temperature for the time of year of the tests. 2. Locomotion was in the labriform mode. Within this mode two pectoral-fin patterns were observed, differing only in the details of fin kinematics. These differences resulted from the length of the propagated wave passed over the fin. At low swimming speeds, up to about 2 L/sec, the wavelength was relatively short, approximately twice the length of the trailing edge of the fin. At higher speeds, a wave of very much longer wavelength was passed over the fin. 3. The pectoral fin-beat cycle was divisible into abduction, adduction and refractory phases. Abduction and adduction phases were of equal duration, and the proportion of time occupied by these phases increased with swimming speed. The duration of the refractory phase decreased with increasing speed. 4. The kinematics indicated that thrust was generated throughout abduction and adduction phases, together with lift forces that cancelled out over a complete cycle. As a result of lift forces and the refractory phase the body moved in a figure-8 motion relative to the flow. 5. Pectoral fin-beat frequency and amplitude increased with swimming speed, and the product of frequencyxamplitude was linearly related to swimming speed. 6. Interactions between pectoral fin-beat frequency, amplitude, refractory phase and kinematic patterns were interpreted as a mechanism to permit the propulsive muscles to operate at optimum efficiency and power output over a wider range of swimming speeds than would otherwise be possible. 7. Pectoral-fin propulsion was augmented by caudal-fin propulsion only at swimming speeds greater than 3·4 L/sec. 8. The mean 45 min critical swimming speed was 3·94 L/sec, and compares favourably with similar levels of activity for fish swimming by means of body and caudal-fin movements.


1994 ◽  
Vol 192 (1) ◽  
pp. 45-59 ◽  
Author(s):  
H Dewar ◽  
J Graham

Yellowfin tuna (Thunnus albacares) swimming kinematics was studied in a large water tunnel at controlled swimming velocities (U). Quantified kinematic variables included the tail-beat frequency, stride length (l), caudal amplitude, yaw, the propulsive wavelength, the speed of the propulsive wave (C) and the sweepback angle of the pectoral fins. In general, all variables, except the propulsive wavelength and consequently C, are comparable to values determined for other teleosts. The propulsive wavelength for the tunas (1.23­1.29 L, where L is fork length) is 30­60 % longer than in other cruise-adapted teleosts such as salmonids. The resulting thunniform swimming mode and the morphological and anatomical adaptations associated with the long propulsive wavelength (e.g. fusiform body shape, rigid vertebral column) act to minimize anterior resistance and maximize caudal thrust. The long propulsive wavelength also increases the maximum l which, in concert with the elevated muscle temperatures of tunas, increases their maximum swimming velocity.


1999 ◽  
Vol 202 (24) ◽  
pp. 3523-3539 ◽  
Author(s):  
L.J. Rosenberger ◽  
M.W. Westneat

Rajiform locomotion is a unique swimming style found in the batoid fishes (skates and rays) in which thrust is generated by undulatory waves passing down the enlarged pectoral fins. We examined the kinematic patterns of fin motion and the motor patterns of pectoral fin muscles driving the locomotor system in the blue-spot stingray Taeniura lymma. Our goals in this study were to determine overall patterns of fin motion and motor control during undulatory locomotion, to discover how these patterns change with swimming velocity and to correlate muscle function with kinematics and pectoral morphology. Kinematic data were recorded from five individuals over a range of swimming speeds from 22 to 55 cm s(−)(1) (0.9-3.0 DL s(−)(1), where DL is body disc length). Electromyographic (EMG) data were recorded from three individuals over a range of velocities (1.2-3.0 DL s(−)(1)) at seven locations (four dorsal, three ventral) along the pectoral fin. As swimming velocity increases, fin-beat frequency, wavespeed and stride length increase, number of waves and reduced frequency decrease and fin amplitude remains constant. There is variability among individuals in frequency and amplitude at a given speed. An inverse relationship was found in which a high fin-beat frequency is associated with a low fin amplitude and a low fin-beat frequency is associated with a high fin amplitude. The motor pattern of undulatory locomotion is alternate firing activity in the dorsal and ventral muscles as the wave moves along the fin from anterior to posterior. Fin muscles are active along the entire length of the fin except at the lowest speeds. As swimming velocity and fin-beat frequency increase, the time of activation of posterior muscles becomes earlier relative to the onset of activity in the anterior dorsal muscles. The duration of muscle activity is longer in the ventral muscles than in the dorsal muscles, indicating that they play a central role in the power stroke of the fin-beat cycle. The anterior muscles (dorsal and ventral) are active for a relatively longer part of the stride cycle than the posterior muscles. Both the anterior position and the large duty factor of the anterior muscles reflect the role of these muscles in initial wave generation. Synchronous recordings of kinematic data with EMG data reveal that the anterior dorsal and middle ventral muscles do mostly positive work, whereas the dorsal and ventral posterior muscles do negative work at most swimming speeds.


1990 ◽  
Vol 151 (1) ◽  
pp. 175-192 ◽  
Author(s):  
JEFFREY B. GRAHAM ◽  
HEIDI DEWAR ◽  
N. C. LAI ◽  
WILLIAM R. LOWELL ◽  
STEVE M. ARCE

A large, sea-going water tunnel was used in various studies of shark swimming performance. The critical swimming velocity (Ucrit, an index of aerobically sustainable swimming speed) of a 70 cm long lemon shark (Negaprion brevirostris Poey) was determined to be 1.1 Ls−1, where L is body length. The Ucrit of the leopard shark (Triakis semifasciata Girard) was found to vary inversely with body size; from about 1.6Ls−1in 30–50cm sharks to 0.6LS−1 in 120cm sharks. Large Triakis adopt ram gill ventilation at swimming speeds between 27 and 60cms−1, which is similar to the speed at which this transition occurs in teleosts. Analyses of tail-beat frequency (TBF) in relation to velocity and body size show that smaller Triakis have a higher TBF and can swim at higher relative speeds. TBF, however, approaches a maximal value at speeds approaching Ucrit, suggesting that red muscle contraction velocity may limit sustained swimming speed. The TBF of both Triakis and Negaprion rises at a faster rate with swimming velocity than does that of the more thunniform mako shark (Isurus oxyrinchus Rafinesque). This is consistent with the expectation that, at comparable relative speeds, sharks adapted for efficient swimming should have a lower TBF. The rates of O2 consumption of swimming lemon and mako sharks are among the highest yet measured for elasmobranchs and are comparable to those of cruise-adapted teleosts.


2000 ◽  
Vol 203 (16) ◽  
pp. 2379-2393 ◽  
Author(s):  
E.G. Drucker ◽  
G.V. Lauder

Past study of interspecific variation in the swimming speed of fishes has focused on internal physiological mechanisms that may limit the ability of locomotor muscle to generate power. In this paper, we approach the question of why some fishes are able to swim faster than others from a hydrodynamic perspective, using the technique of digital particle image velocimetry which allows measurement of fluid velocity and estimation of wake momentum and mechanical forces for locomotion. We investigate the structure and strength of the wake in three dimensions to determine how hydrodynamic force varies in two species that differ markedly in maximum swimming speed. Black surfperch (Embiotoca jacksoni) and bluegill sunfish (Lepomis macrochirus) swim at low speeds using their pectoral fins exclusively, and at higher speeds switch to combined pectoral and caudal fin locomotion. E. jacksoni can swim twice as fast as similarly sized L. macrochirus using the pectoral fins alone. The pectoral fin wake of black surfperch at all speeds consists of two distinct vortex rings linked ventrally. As speed increases from 1.0 to 3.0 L s(−)(1), where L is total body length, the vortex ring formed on the fin downstroke reorients to direct force increasingly downstream, parallel to the direction of locomotion. The ratio of laterally to downstream-directed force declines from 0.93 to 0.07 as speed increases. In contrast, the sunfish pectoral fin generates a single vortex ring per fin beat at low swimming speeds and a pair of linked vortex rings (with one ring only partially complete and attached to the body) at maximal labriform speeds. Across a biologically relevant range of swimming speeds, bluegill sunfish generate relatively large lateral forces with the paired fins: the ratio of lateral to downstream force remains at or above 1.0 at all speeds. By increasing wake momentum and by orienting this momentum in a direction more favorable for thrust than for lateral force, black surfperch are able to swim at twice the speed of bluegill sunfish using the pectoral fins. In sunfish, without a reorientation of shed vortices, increases in power output of pectoral fin muscle would have little effect on maximum locomotor speed. We present two hypotheses relating locomotor stability, maneuverability and the structure of the vortex wake. First, at low speeds, the large lateral forces exhibited by both species may be necessary for stability. Second, we propose a potential hydrodynamic trade-off between speed and maneuverability that arises as a geometric consequence of the orientation of vortex rings shed by the pectoral fins. Bluegill sunfish may be more maneuverable because of their ability to generate large mediolateral force asymmetries between the left- and right-side fins.


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