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.

scholarly journals ‘Steady’ Swimming Kinematics of Tiger Musky, an Esociform Accelerator, and Rainbow Trout, a Generalist Cruiser

1988 ◽  
Vol 138 (1) ◽  
pp. 51-69 ◽  
Author(s):  
PAUL W. WEBB
Keyword(s):  
Rainbow Trout ◽  
Lateral Displacement ◽  
Phase Relationship ◽  
Total Body Length ◽  
The Body ◽  
Salmo Gairdneri ◽  
Trailing Edge ◽  
Drag Coefficients ◽  
Total Body ◽  
Tail Beat

Locomotor kinematics of tiger musky (Esox sp.) and rainbow trout (Salmo gairdneri) were measured at ‘steady’ swimming speeds of up to 85 cm s−1. Tail beat frequencies of musky were approximately 2 Hz higher than those of trout at any swimming speed, but tail beat amplitudes were 0.04L (where L is total body length) smaller. The product of these two variables was similar for the two species at any speed. The length of the propulsive wave was independent of speed, and was 0.8L for musky, somewhat smaller than the value for trout, 0.9L. The depth of the caudal fin trailing edge of trout was greater than that of musky, but the greater depth of the posteriorly located median fins of musky also contributed to thrust production. The cosine of the angle of the trailing edge to its beat plane showed the same phase relationship with lateral displacement in both musky and trout. It increased with speed for both species, and values for musky were slightly smaller. Thrust power requirements of musky and trout were similar. Thrust (= drag) coefficients of musky were 1.55 times larger than those for trout: this is roughly as expected on the basis of the larger proportion of the total area of musky located caudally and the higher drag coefficients in this region of the body. Lateral recoil movements of musky were unexpectedly smaller than for trout and were associated with smaller energy wastage from undamped recoil movements. The large recoil expected for the body form of musky was damped to some extent by higher tail beat frequencies, although this entailed some loss in Froude efficiency. Otherwise, no hydrodynamic explanation for the small recoil movements of musky was apparent. It is suggested that the myotomal muscles could be involved in minimizing recoil. The esociform morphology incurs costs in steady swimming, in comparison with generalist cruises, because of reduced sprint speeds for fish of a given length or increased power requirements for fish of a given mass.

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.

Kinematics and efficiency of steady swimming in adult axolotls (Ambystoma mexicanum)

1997 ◽  
Vol 200 (13) ◽  
pp. 1863-1871 ◽  
Author(s):  
K D'Août ◽  
P Aerts
Keyword(s):  
Swimming Speed ◽  
High Speed ◽  
Natural Habitat ◽  
Total Body Length ◽  
Ambystoma Mexicanum ◽  
The Body ◽  
Entire Body ◽  
Amplitude Profile ◽  
Wide Range ◽  
Tail Tip

The kinematics of steady swimming at a wide range of velocities was analysed using high-speed video recordings (500 frames s-1) of eight individuals of Ambystoma mexicanum swimming through a tunnel containing stationary water. Animals in the observed size range (0.135­0.238 m total body length) prefer to swim at similar absolute speeds, irrespective of their body size. The swimming mechanism is of the anguilliform type. The measured kinematic variables ­ the speed, length, frequency and amplitude (along the entire body) of the propulsive wave ­ are more similar to those of anguilliform swimming fish than to those of tadpoles, in spite of common morphological features with the latter, such as limbs, external gills and a tapering tail. The swimming speed for a given animal size correlates linearly with the tailbeat frequency (r2=0.71), whereas the wavelength and tail-tip amplitude do not correlate with this variable. The shape of the amplitude profile along the body, however, is very variable between the different swimming bouts, even at similar speeds. It is suggested that, for a given frequency, the amplitude profile along the body is adjusted in a variable way to yield the resulting swimming speed rather than maintaining a fixed-amplitude profile. The swimming efficiency was estimated by calculating two kinematic variables (the stride length and the propeller efficiency) and by applying two hydrodynamic theories, the elongated-body theory and an extension of this theory accounting for the slope at the tail tip. The latter theory was found to be the most appropriate for the axolotl's swimming mode and yields a hydromechanical efficiency of 0.75±0.04 (mean ± s.d.), indicating that Ambystoma mexicanum swims less efficiently than do anuran tadpoles and most fishes. This can be understood given its natural habitat in vegetation at the bottom of lakes, which would favour manoeuvrability and fast escape.

Thelastoma gueyei sp. n. (Nematoda: Thelastomatidae) from the Senegal diplopod Archispirostreptus tumuliporus (Diplopoda: Spirostreptidae)

Nematology ◽  
2006 ◽  
Vol 8 (5) ◽  
pp. 739-747 ◽  
Author(s):  
Božena Koubková ◽  
Vlastimil Baruš ◽  
Iveta Matějusová ◽  
Iveta Hodová ◽  
Petr Koubek
Keyword(s):  
Ribosomal Rna ◽  
Morphological Characteristics ◽  
Total Body Length ◽  
Small Subunit ◽  
Species Group ◽  
The Body ◽  
Pharyngeal Bulb ◽  
Genital Cone ◽  
Tail Spike ◽  
Total Body

Abstract Thelastoma gueyei sp. n., a nematode belonging to the long-tailed species group of the genusThelastoma, is described from the diplopodArchispirostreptus tumuliporus (Spirostreptidae) collected in Niokolo Koba National Park (Senegal, West Africa).Thelastoma gueyei sp. n. is morphologically most similar toT. gipetiti. Females are characterised by: the vulva being situated in the posterior half of the body and near to the anus (V′ = 75-86) with the anterior vulval lip developed into a prominent flap; excretory pore located at the level of the anterior end of the pharyngeal bulb; b′ = 28-38 and tail, expressed as a proportion of L′, = 1.7-2.7. Males have narrow cuticular alae extending from about the middle of the pharynx to the level of the anteriormost pair of copulatory papillae; four pairs of copulatory papillae, two large, subventral, pairs being located adcloacally on the genital cone, a third, much smaller pair on the posterior margin of the genital cone and the last pair being situated at the mid-point of the tail spike; and a tail occupying 10.8-13.2% of the total body length. The distal tip of the spicule is drop-shaped. Morphological characteristics were studied using scanning electron microscopy and a comparison of the long-tailed group of thelastomatids is provided. Nucleic acid sequence of the small subunit ribosomal RNA gene was obtained for purposes of DNA barcoding.

scholarly journals PENGUKURAN PANJANG TUBUH CACING NIPAH PENDEK Namalycastis abiuma (POLYCHAETA: NEREDIDAE) DARI PERAIRAN MANGROVE SUNGAI KAPUAS KALIMANTAN BARAT

2018 ◽  
Vol 11 (2) ◽  
pp. 183-189
Author(s):  
Junardi Junardi
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Body Length ◽  
Anterior Segment ◽  
Total Body Length ◽  
The Body ◽  
Female Body Size ◽  
Alternative Approach ◽  
Total Body ◽  
The Relationship

AbstrakCacing Nipah Pendek Namalycastis abiuma memiliki tubuh yang elastis dan mudah putus sehingga diperlukan pendekatan morfometri tubuh lain untuk menentukan panjang tubuh sesungguhnya. Tujuan penelitian ini untuk menentukan panjang tubuh total cacing nipah pendek dengan menggunakan bobot tubuh, jumlah total segmen berseta, panjang tiga segmen anterior pertama (L3) dan lebar segmen berseta atau setiger ke-10 (S-10). Spesimen yang digunakan dipilih hanya individu yang lengkap dan utuh. Pengukuran dilakukan dibawah mikroskop dengan lensa okular yang dilengkapi dengan mikrometer. Data dianalisis dengan analisis korelasi. Cacing yang digunakan sebanyak 258 individu yang terdiri atas 190 immature, 54 submature dan 14 mature dengan ukuran panjang tubuh rata-rata berturut-turut 108,62±34,80 mm, 172,27±42,78 mm dan 123,14±57,40 mm. Cacing betina ditemukan memiliki ukuran tubuh lebih besar dari jantan. Panjang tubuh N. abiuma dapat diduga dengan bobot tubuh, panjang L3 dan lebar S-10 dengan nilai koefisien korelasi (r) berturut-turut 0,82, 0,73 dan 0,78. Pendekatan morfometri dapat digunakan untuk menentukan ukuran tubuh N. abiuma.Abstract The short nypa palm worm Namalycastis abiuma has an elastic and fragile body. Therefore, an alternative approach of morphometrical techniques is needed to determine the total body length. This research aimed to estimate the total body length of the short nypa palm worm based on body weight, the total number of segments, the length of the first three anterior segment (L3) and the tenth setiger width (S10). Body measurement was done using stereomicroscope fitted with the micrometer. Correlation analysis was done to describe the relationship between the length of L3 and the width of S10. A total of 258 complete and whole specimens consisted of 190 immature, 54 submature, and 14 mature individuals. The average body length of immature individuals was 108.62±34.80 mm, 172.27±42.78 mm for sub mature individuals, and 123.14±57.40 mm for mature individuals. Based on sexual dimorphism, the female body size is larger than male. The body length of N. abiuma can be estimated by body weight, the length of L3, and the  width of S10, with  correlation coefficient (r) of 0.82, 0.73 and 0.78, respectively. Morphometry approach can be used to determine the body size of N. abiuma. 

scholarly journals Hydrodynamics of linear acceleration in bluegill sunfish Lepomis macrochirus

2018 ◽  
Author(s):  
Tyler N. Wise ◽  
Margot A. B. Schwalbe ◽  
Eric D. Tytell
Keyword(s):  
Swimming Speed ◽  
High Speed ◽  
Fluid Dynamic ◽  
Natural Habitat ◽  
Lepomis Macrochirus ◽  
Linear Acceleration ◽  
High Amplitude ◽  
The Body ◽  
Bluegill Sunfish ◽  
Tail Beat

SUMMARY STATEMENTBluegill sunfish accelerate primarily by increasing the total amount of force produced in each tail beat but not by substantially redirecting forces.ABSTRACTIn their natural habitat, fish rarely swim steadily. Instead they frequently accelerate and decelerate. Relatively little is known about how fish produce extra force for acceleration in routine swimming behavior. In this study, we examined the flow around bluegill sunfish Lepomis macrochirus during steady swimming and during forward acceleration, starting at a range of initial swimming speeds. We found that bluegill produce vortices with higher circulation during acceleration, indicating a higher force per tail beat, but do not substantially redirect the force. We quantified the flow patterns using high speed video and particle image velocimetry and measured acceleration with small inertial measurement units attached to each fish. Even in steady tail beats, the fish accelerates slightly during each tail beat, and the magnitude of the acceleration varies. In steady tail beats, however, a high acceleration is followed by a lower acceleration or a deceleration, so that the swimming speed is maintained; in unsteady tail beats, the fish maintains the acceleration over several tailbeats, so that the swimming speed increases. We can thus compare the wake and kinematics during single steady and unsteady tailbeats that have the same peak acceleration. During unsteady tailbeats when the fish accelerates forward for several tailbeats, the wake vortex forces are much higher than those at the same acceleration during single tailbeats in steady swimming. The fish also undulates its body at higher amplitude and frequency during unsteady tailbeats. These kinematic changes likely increase the fluid dynamic added mass of the body, increasing the forces required to sustain acceleration over several tailbeats. The high amplitude and high frequency movements are also likely required to generate the higher forces needed for acceleration. Thus, it appears that bluegill sunfish face a tradeoff during acceleration: the body movements required for acceleration also make it harder to accelerate.

scholarly journals Length-weight relationship of European catfish (Silurus glanis L.) fry reared at different stocking densities under controlled conditions

2021 ◽  
pp. 47-51
Author(s):  
V. Krasteva ◽  
M. Yankova
Keyword(s):  
Body Length ◽  
Stocking Density ◽  
Total Body Length ◽  
The Body ◽  
Small Fish ◽  
Silurus Glanis ◽  
Group A ◽  
European Catfish ◽  
Total Body ◽  
Group B

Abstract. The present paper investigates the body length and weight, and the size-weight variations of one-month-old European catfish reared at 4 variants of stocking density: Variant 1 – 5 spec/l; Variant 2 – 10 spec/l; Variant 3 – 15 spec/l and Variant 4 – 28 spec/l. The experiment is carried out at the Institute of Fisheries and Aquaculture, Plovdiv for a period of 16 days, using a production system consisting of tubs with continuous water flow (0.7 l/min). At the end of the experiment, the fish from each variant are sorted in three size-weight groups: A – large, B – medium and C – small. The number of fish in each group is established. From the group of the medium- and small-sized fish, 150 speciments are measured, while from the group of the large specimens, which are the smallest in number, all specimens are measured for the biometric parameters body weight (BW, g) and total body length (TL, cm). The results from the study show small variations in the length and weight of the fish reared at the lowest stocking density (Variant 1). As the density increase, the size-weight differences between the specimens from Group A also increased, while of those from Group B they decrease. The number of the medium-sized fish decrease (p≤0.001) while the number of large specimens (p≤0.01) and small fish increase (p≤0.001).

Development of a Bioinspired Underwater Robot Using a Single Actuator

2017 ◽  
Vol 51 (5) ◽  
pp. 94-102
Author(s):  
Myoung-Jae Jun ◽  
Chang-Soo Han
Keyword(s):  
The Body ◽  
Inertia Force ◽  
Underwater Robot ◽  
Restoring Force ◽  
Total Body Mass ◽  
Pectoral Fins ◽  
Propulsion Mechanism ◽  
Total Body ◽  
Motion Characteristics ◽  
Direction Opposite

Abstract We propose a novel propulsion mechanism for an underwater robot inspired by the pectoral fins of a fish. This device is referred to as the “flipper.” The flipper is connected to a rotational motor, and its shape is similar to that of the real fish's fins. The flipper using the propulsion mechanism proposed in this study has 1 degree of freedom. We can control the test robot during forward motion as well as its direction-changing operation. The experimental test robot is composed of a flipper at the front of the robot's head, together with a body and a tail/vertical fin. The electronic components are installed into the body. The tail functions to maintain the horizontal/vertical balance of the robot. Forward propulsion is achieved through the rotation of the flipper. The robot's direction can be changed by repeated oscillation of the flipper in a direction opposite to that of the desired angle. Several experiments were performed to measure the thrust force of the experimental robot and its motion characteristics in a test water pool. The experimental results show that the proposed propulsion method is viable.<def-list> Nomenclature <def-item> <term> F T </term> <def> = Thrust </def> </def-item> <def-item> <term> F I </term> <def> = Inertia force </def> </def-item> <def-item> <term> F B </term> <def> = Buoyancy </def> </def-item> <def-item> <term> B V </term> <def> = Platform volume </def> </def-item> <def-item> <term> V target </term> <def> = Target speed </def> </def-item> <def-item> <term> ρ </term> <def> = Water density </def> </def-item> <def-item> <term> P </term> <def> = Flipper pitch </def> </def-item> <def-item> <term> D </term> <def> = Drag force </def> </def-item> <def-item> <term> C D </term> <def> = Drag coefficient </def> </def-item> <def-item> <term> A </term> <def> = Projection of the frontal area </def> </def-item> <def-item> <term> T </term> <def> = Effective power </def> </def-item> <def-item> <term> P m </term> <def> = Propeller power </def> </def-item> <def-item> <term> C M </term> <def> = Center of total body mass </def> </def-item> <def-item> <term> C B </term> <def> = Center of buoyancy </def> </def-item> <def-item> <term> C F </term> <def> = Center of flipper mass </def> </def-item> <def-item> <term> F DS </term> <def> = Restoring force </def> </def-item> <def-item> <term> g </term> <def> = Gravity </def> </def-item> <def-item> <term> Q </term> <def> = Motor torque at maximum revolutions per minute </def> </def-item> <def-item> <term> rps reasonable </term> <def> = Reasonable revolutions per second </def> </def-item> </def-list>

Locomotor function of the dorsal fin in teleost fishes: experimental analysis of wake forces in sunfish

2001 ◽  
Vol 204 (17) ◽  
pp. 2943-2958 ◽  
Author(s):  
Eliot G. Drucker ◽  
George V. Lauder
Keyword(s):  
High Speed ◽  
Lepomis Macrochirus ◽  
The Body ◽  
Cycle Period ◽  
Teleost Fishes ◽  
Caudal Fin ◽  
Locomotor System ◽  
Pectoral Fins ◽  
Dorsal Fin

SUMMARYA key evolutionary transformation of the locomotor system of ray-finned fishes is the morphological elaboration of the dorsal fin. Within Teleostei, the dorsal fin primitively is a single midline structure supported by soft, flexible fin rays. In its derived condition, the fin is made up of two anatomically distinct portions: an anterior section supported by spines, and a posterior section that is soft-rayed. We have a very limited understanding of the functional significance of this evolutionary variation in dorsal fin design. To initiate empirical hydrodynamic study of dorsal fin function in teleost fishes, we analyzed the wake created by the soft dorsal fin of bluegill sunfish (Lepomis macrochirus) during both steady swimming and unsteady turning maneuvers. Digital particle image velocimetry was used to visualize wake structures and to calculate in vivo locomotor forces. Study of the vortices generated simultaneously by the soft dorsal and caudal fins during locomotion allowed experimental characterization of median-fin wake interactions.During high-speed swimming (i.e. above the gait transition from pectoral- to median-fin locomotion), the soft dorsal fin undergoes regular oscillatory motion which, in comparison with analogous movement by the tail, is phase-advanced (by 30% of the cycle period) and of lower sweep amplitude (by 1.0cm). Undulations of the soft dorsal fin during steady swimming at 1.1bodylengths−1 generate a reverse von Kármán vortex street wake that contributes 12% of total thrust. During low-speed turns, the soft dorsal fin produces discrete pairs of counterrotating vortices with a central region of high-velocity jet flow. This vortex wake, generated in the latter stage of the turn and posterior to the center of mass of the body, counteracts torque generated earlier in the turn by the anteriorly positioned pectoral fins and thereby corrects the heading of the fish as it begins to translate forward away from the turning stimulus. One-third of the laterally directed fluid force measured during turning is developed by the soft dorsal fin. For steady swimming, we present empirical evidence that vortex structures generated by the soft dorsal fin upstream can constructively interact with those produced by the caudal fin downstream. Reinforcement of circulation around the tail through interception of the dorsal fin’s vortices is proposed as a mechanism for augmenting wake energy and enhancing thrust.Swimming in fishes involves the partitioning of locomotor force among several independent fin systems. Coordinated use of the pectoral fins, caudal fin and soft dorsal fin to increase wake momentum, as documented for L. macrochirus, highlights the ability of teleost fishes to employ multiple propulsors simultaneously for controlling complex swimming behaviors.

scholarly journals A new xandarellid euarthropod from the Cambrian Chengjiang biota, Yunnan Province, China

2018 ◽  
Vol 156 (08) ◽  
pp. 1375-1384 ◽  
Author(s):  
Xianguang Hou ◽  
Mark Williams ◽  
Robert Sansom ◽  
Derek J. Siveter ◽  
David J. Siveter ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Body Length ◽  
Yunnan Province ◽  
Total Body Length ◽  
The Body ◽  
Mode Of Life ◽  
Chengjiang Biota ◽  
Total Body

AbstractThe euarthropod Luohuilinella deletres sp. nov. is described from rare material from the Chengjiang biota, Cambrian Series 2, Stage 3, of Yunnan Province, China. Phylogenetic analysis recovers a xandarellid affinity for L. deletres, representing only the fifth described species of this clade. L. deletres possesses a head shield that is about one-fifth of the total body length and a trunk with 30 tergites, the reduced anterior-most tergite and terminal three tergites lacking pleural elongations. Anteriorly situated notches in the head shield are associated with stalked eyes, in contrast to the more posterior, enclosed eye slits present in Xandarella. Posterior to the antennae there are at least 11 pairs of biramous appendages preserved, including three pairs in the head. The morphology of the midline gut of L. deletres, in which lateral, unbranched diverticula are wider towards the front of the body, is a characteristic also found in various trilobites. The dorsoventrally flattened exoskeleton suggests a benthic or nektobenthic mode of life for L. deletres, as for other trilobitomorphs, and it likely used its well-developed anteriorly positioned eyes for searching out food, either to scavenge or to find prey.

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