Fin Stroke Research Articles

COMPARISON OF THREE CONCENTRATIONS OF AQUA-SEDTM FOR IMMERSION EUTHANASIA OF BUTTERFLY SPLITFIN (AMECA SPLENDENS).

The efficacies of three concentrations of 2-phenoxyethanol from Aqua-sedTM were examined to determine the suitability for euthanasia of butterfly splitfin (Ameca splendens). Thirty fish were randomly assigned to be immersed in one of three Aqua-SedTM concentrations: 0.5, 2, and 6 ml/L. Opercular rates and caudal fin stroke rates were quantified, and time to the cessation of physiological measures including heartbeat, caudal fin strokes, reaction to external stimuli, righting reflex, swimming, and operculation were recorded. To test for the effects of concentration of Aqua-sedTM on all times to cessation of physiological measures, a linear mixed model was performed followed by pairwise comparisons with a Bonferroni correction. A proportions test compared the number of fish that lost their heartbeat across Aqua-sedTM concentrations. Varying anesthetic induction times were observed for all three Aqua-sedTM concentrations; time to cessation of physiological measures was fastest with 6 ml/L, followed by 2 then 0.5 ml/L, but only concentrations of 2 and 6 ml/L induced anesthesia in less than the recommended 180 s. Aqua-sedTM concentration had a significant effect on time to cessation of physiological measures (P < 0.01), but not on time to cessation of a heartbeat (P > 0.05). Pairwise comparisons indicate time to cessation of caudal fin strokes, reaction to external stimuli, righting reflex, and swimming significantly decreased as concentration increased (P < 0.01). After 60 min of immersion in Aqua-sedTM the number of fish without a heartbeat differed significantly across concentrations (P < 0.01); 20% of fish immersed in 0.5 ml/L, 90% of fish immersed in 2 ml/L, and 90% of fish immersed in 6 ml/L had no heartbeat. A minimum dose of 2 ml/L of Aqua-sedTM, and an immersion time of 60 min for euthanasia of butterfly splitfin is recommended, with a secondary euthanasia measure to confirm death when the heartbeat remains.

USE OF TRICAINE METHANESULFONATE, CLOVE OIL AND 2-PHENOXYETHANOL FOR IMMERSION EUTHANASIA OF UNGA CICHLIDS (SAROTHERODON LINELLII).

Fish may warrant euthanasia for a variety of reasons, but euthanasia may be difficult to accomplish or confirm because fish can recover from deep anesthesia even after cardiac and respiratory arrest. The efficacies of three types of anesthetics were evaluated to compare their suitability for euthanasia of Unga cichlids (Sarotherodon linellii). Thirty cichlids were randomly assigned to be immersed in one of the three anesthetic solutions: tricaine methanesulfonate (MS-222), 2-phenoxyethanol (2-PE), and clove oil (CO) at doses of 1,000 mg/L, 2 mL/L, and 500 mg/L respectively. The opercular rates and caudal fin stroke rates were quantified, and the time to cessation of physiological measures (CPM) including caudal fin strokes, the reaction to external stimuli, the righting reflex, swimming, and operculation were recorded. Varying anesthetic induction times were observed with all three euthanasia solutions; the time to CPM in the 2-PE group occurred at a significantly slower rate than in the MS-222 group (P < 0.01). No significant differences were identified for the time to CPM when comparing the standard length or weight of the cichlids in all euthanasia solutions (P > 0.05). The cost of euthanasia per cichlid was calculated, with the most economically viable option being 2-PE; at more than seven times the price of 2-PE, MS-222 was the most expensive. After a 60-min immersion in the euthanasia solution, the presence of an audible heartbeat was identified in 100% of the cichlids immersed in 2-PE, 100% immersed in CO, and 90% in MS-222, indicating that they were not reliably euthanized. Therefore, a two-step protocol is recommended in cichlids for euthanasia: heavy anesthesia via immersion followed by an intravenous or intracardiac injection of euthanasia solution, or other secondary method of euthanasia.

Navigation: from animal behaviour to guiding principles

![Figure][1] Tritonia diomedea navigating through a sea pen bed in search of prey or mates. Photo credit: Russell Wyeth and James A. Murray. Whether an animal's world is restricted to a few twigs or the avian highways that traverse the planet, creatures must navigate their surroundings

Pectoral fin kinematics and motor patterns are shaped by fin ray mechanosensation during steady swimming in Scarus quoyi.

For many fish species, rhythmic movement of the pectoral fins, or forelimbs, drives locomotion. In terrestrial vertebrates, normal limb-based rhythmic gaits require ongoing modulation with limb mechanosensors. Given the complexity of the fluid environment and dexterity of fish swimming through it, we hypothesize that mechanosensory modulation is also critical to normal fin-based swimming. Here, we examined the role of sensory feedback from the pectoral fin rays and membrane on the neuromuscular control and kinematics of pectoral fin-based locomotion. Pectoral fin kinematics and electromyograms of the six major fin muscles of the parrotfish, Scarus quoyi, a high-performance pectoral fin swimmer, were recorded during steady swimming before and after bilateral transection of the sensory nerves extending into the rays and surrounding membrane. Alternating activity of antagonistic muscles was observed and drove the fin in a figure-of-eight fin stroke trajectory before and after nerve transection. After bilateral transections, pectoral fin rhythmicity remained the same or increased. Differences in fin kinematics with the loss of sensory feedback also included fin kinematics with a significantly more inclined stroke plane angle, an increased angular velocity and fin beat frequency, and a transition to the body-caudal fin gait at lower speeds. After transection, muscles were active over a larger proportion of the fin stroke, with overlapping activation of antagonistic muscles rarely observed in the trials of intact fish. The increased overlap of antagonistic muscle activity might stiffen the fin system in order to enhance control and stability in the absence of sensory feedback from the fin rays. These results indicate that fin ray sensation is not necessary to generate the underlying rhythm of fin movement, but contributes to the specification of pectoral fin motor pattern and movement during rhythmic swimming.

Predicting propulsive forces using distributed sensors in a compliant, high DOF, robotic fin

Engineered robotic fins have adapted principles of propulsion from bony-finned fish, using spatially-varying compliance and complex kinematics to produce and control the fin’s propulsive force through time. While methods of force production are well understood, few models exist to predict the propulsive forces of a compliant, high degree of freedom, robotic fin as it moves through fluid. Inspired by evidence that the bluegill sunfish (Lepomis macrochirus) has bending sensation in its pectoral fins, the objective of this study is to understand how sensors distributed within a compliant robotic fin can be used to estimate and predict the fin’s propulsive force. A biorobotic model of a bluegill sunfish pectoral fin was instrumented with pressure and bending sensors at multiple locations. Experiments with the robotic fin were executed that varied the swimming gait, flapping frequency, stroke phase, and fin stiffness to understand the forces and sensory measures that occur during swimming. A convolution-based, multi-input-single-output (MISO) model was selected to model and study the relationships between sensory data and propulsive force. Subsets of sensory data were studied to determine which sensor modalities and sensor placement locations resulted in the best force predictions. The propulsive forces of the fin were accurately predicted using the linear MISO model on intrinsic sensory data. Bending sensation was more effective than pressure sensation for predicting propulsive forces, and the importance of bending sensation was consistent with several results in biology and engineering studies. It was important to have a spatial distribution of sensors and multiple sensory modalities in order to predict forces across large changes to dynamics. The relationship between propulsive forces and intrinsic sensory measures is complex, and good models should allow for temporal lags between forces and sensory data, changes to the model within a fin stroke, and changes to the model through gait transitions.

가상경계볼쯔만법을 이용한 자력추진 물고기 운동 익의 유영해석

Immersed boundary lattice Boltzmann method has been applied to analyze the characteristics of the self-propelled fish motion swimming robot. The airfoil NACA0012 with caudal fin stroke model was considered to examine the characteristics. The foil in steady forward motion and a combination of steady-state harmonic deformation produces thrust through the formation of a flow downstream from the trailing edge. The harmonic motion of the foil causes unsteady shedding of vorticity from the trailing edge, while forming the vortices at the leading edge as well. The resultant thrust is developed by the pressure difference formed on the upper and lower surface of the airfoil. and the time averaged thrust coefficient increases as Re increase in the region of <TEX>$Re{\leqq}700$</TEX>. The suggested numerical method is suitable to develop the fish-motion model to control the swimming robot, however It would need to extend in 3D analysis to examine the higher Re and to determine the more detail mechanism of thrust production.

Computations of Flapping Flow Propulsion for Unmanned Underwater Vehicle Design

Three-dimensional unsteady computations of the flow past a flapping and deforming fin are performed. The computed unsteady lift and thrust force-time histories are validated with experimental data and are in good agreement. Several fin parametric studies are performed for a notional unmanned underwater vehicle. The parametric studies investigated the force production of the fin as a function of varying the flexibility, the bulk amplitude of fin rotation, the vehicle speed, and the fin stroke bias angle. The results of these simulations are used to evaluate the hydrodynamic performance of the vehicle and to support controller development. Computations are also performed to map out the hydrodynamic characteristics of a new test vehicle, designed and built at Naval Research Laboratory to demonstrate the hovering and low-speed maneuvering performance of a set of actively controlled curvature fins.

2P2-H24 イルカの尾びれ型振動翼の推進性能の研究(バイオミメティクス・ロボティクス)

A propulsion system with a Dolphin-like fin stroke has been proposed as a novel propulsion system with higher propulsive efficiency and higher safety than a conventional screw propeller As a result, it promotes to the improvement of environmental problems. It is known that a dolphin swims fast and freely in water. The propulsive performance and the kinetic performance of the dolphin are one of great concern among researchers. We paid attention to the dolphin's tail flukes which has an important role to generate propulsive force. So the experiments on both the propulsive force of the outboard propulsor with the oscillating wing which is similar to a real tail flukes of dolphin in shape and the velocity of a small boat equipped with the outboard propulsor were carried out. The propulsive performance of the wing like a dolphin's tail was discussed compared with rectangular wings.

Non-invasive measurement of instantaneous forces during aquatic locomotion: a case study of the bluegill sunfish pectoral fin

Swimming and flying animals generate unsteady locomotive forces by delivering net momentum into the fluid wake. Hence, swimming and flying forces can be quantified by measuring the momentum of animal wakes. A recently developed model provides an approach to empirically deduce swimming and flying forces based on the measurement of velocity and vortex added-mass in the animal wake. The model is contingent on the identification of the vortex boundary in the wake. This paper demonstrates the application of that method to a case study quantifying the instantaneous locomotive forces generated by the pectoral fins of the bluegill sunfish (Lepomis macrochirus Rafinesque), measured using digital particle image velocimetry (DPIV). The finite-time Lyapunov exponent (FTLE) field calculated from the DPIV data was used to determine the wake vortex boundary, according to recently developed fluid dynamics theory. Momentum of the vortex wake and its added-mass were determined and the corresponding instantaneous locomotive forces were quantified at discrete time points during the fin stroke. The instantaneous forces estimated in this study agree in magnitude with the time-averaged forces quantified for the pectoral fin of the same species swimming in similar conditions and are consistent with the observed global motion of the animals. A key result of this study is its suggestion that the dynamical effect of the vortex wake on locomotion is to replace the real animal fin with an ;effective appendage', whose geometry is dictated by the FTLE field and whose interaction with the surrounding fluid is wholly dictated by inviscid concepts from potential flow theory. Benefits and limitations of this new framework for non-invasive instantaneous force measurement are discussed, and its application to comparative biomechanics and engineering studies is suggested.

1158 ヒレ船外機の開発に関する研究(J04-2 生物の運動機能/バイオミメティクスとバイオメカニクス/バイオロボティクスとバイオメカトロニクス(2),J04 生物の運動機能/バイオミメティクスとバイオメカニクス/バイオロボティクスとバイオメカトロニクス)

A propulsion system with a fish-like tail fin stroke has been proposed as a novel propulsion system with higher propulsive efficiency and higher safety than a conventional screw propeller. This paper describes the development of an outboard propulsor using an oscillating horizontal fin that is easy to attach to and detach from a small boat. The performance of the outboard propulsor mounting a reflection panel over the fin was investigated. A rigid fin and an elastic fin were used in the experiment. It was found that the outboard oscillating fin propulsor has potential to be environmentally friendly propulsor for small boats such fishing and pleasure boats.

Development Study for Outboard Propulsor Using Oscillating Wing

Propulsion by oscillating a wing in a fish-like tail fin stroke has been proposed as a novel system with higher propulsive efficiency and greater safety than a conventional screw propeller. This paper describes the development of an outboard propulsor using an oscillating wing that is movable and is easy to attach to and detach from a small boat. The behavior of the oscillating wing coupled with the heaving and the pitching motions was realized by use of a new designed crank mechanism with L-shaped links. The propulsive performance of the outboard propulsor using an oscillating wing was investigated. As a result, it was found that the speed of the boat equipped with the outboard propulsor was proportional to the frequency of the oscillating wing. It demonstrated that the outboard propulsor is good for such small boats as fishing boats and pleasure boats as an environmental friendly propulsor.

Wake dynamics and fluid forces of turning maneuvers in sunfish.

While experimental analyses of steady rectilinear locomotion in fishes are common, unsteady movement involving time-dependent variation in heading, speed and acceleration probably accounts for the greatest portion of the locomotor time budget. Turning maneuvers, in particular, are key elements of the unsteady locomotor repertoire of fishes and, by many species, are accomplished by generating asymmetrical forces with the pectoral fins. The development of such left-right asymmetries in force production is a critical and as yet unstudied aspect of aquatic locomotor dynamics. In this paper, we measure the fluid forces exerted by the left and right pectoral fins of bluegill sunfish (Lepomis macrochirus) during turning using digital particle image velocimetry (DPIV). DPIV allowed quantification of water velocity fields, and hence momentum, in the wake of the pectoral fins as sunfish executed turns; forces exerted during turning were compared with those generated by the immediately preceding fin beats during steady swimming. Sunfish generate the forces required for turning by modulating two variables: wake momentum and pectoral fin stroke timing. Fins on opposite sides of the fish play functionally distinct roles during turning maneuvers. The fin nearer the stimulus inducing the turn (i.e. the strong side fin) generates a laterally oriented vortex ring with a strong central jet whose associated lateral force is four times greater than that produced during steady swimming. Little posterior (thrust) force is generated by the strong-side fin, and this fin therefore acts to rotate the body away from the source of the stimulus. The contralateral (weak-side) fin generates a posteriorly oriented vortex ring with a thrust force nine times that produced by the fin during steady swimming. Minimal lateral force is exerted by the weak-side fin, and this fin therefore acts primarily to translate the body linearly away from the stimulus. Turning with the paired fins is not simply steady swimming performed unilaterally. Instead, turning involves asymmetrical fin movements and fluid forces that are distinct in both direction and magnitude from those used to swim forward at constant speed. These data reflect the plasticity of the teleost pectoral fin in performing a wide range of steady and unsteady locomotor tasks.

Bioengineering. Experimental Study on Oscillating Wing for Propulsor with Bending Mechanism Modeled on Caudal Muscle-Skeletal Structure of Tuna.

The purpose of our study is to investigate the effect of the caudal fin behavior resulting from the caudal muscle-skeletal structure of tuna on the propulsive force. A propulsion system by tuna-like fin stroke using two air rubber artificial muscles and a multi-joint bending mechanism (a tuna-like bending mechanism) modeled on the antagonism muscles and the caudal skeletal structure of tuna was developed. In order to realize instructed oscillation of a wing, a method of continuous path follow-up control of a wing in water was discussed in regard to the control of the internal pressure of the artificial muscles. It was found that the optimum control method for the tuna-like bending mechanism was the pressure control of the artificial muscles with both feedforward and pressure feedback compensations. The propulsion performance on a deformable wing using the propulsion system was discussed.

Kinematic and electromyographic analysis of steady pectoral fin swimming in the surfperches

The musculoskeletal mechanism of pectoral fin propulsion was investigated in representatives of the two subfamilies of the Embiotocidae (surfperches). Kinematic and electromyographic records of steady swimming by the open-water cruiser Amphistichus rhodoterus and the benthic maneuverer Embiotoca lateralis were compared at 80 % of the species' respective pectoral&shy;caudal gait transition speeds. Synchronized records of fin movement and the intensity of pectoral muscle activity allowed previous hypotheses of muscle function, based on anatomical lines of action, to be tested. Divisions of the pectoral musculature inserting on the central and trailing- edge fin rays serve simple functions of abduction and adduction. Muscles controlling the fin's leading edge, by contrast, play more complex roles during the fin stroke, including deceleration of the fin at the downstroke&shy;upstroke transition and rotation of the adducted fin during the non-propulsive period between fin beats. In spite of their phylogenetic and ecological divergence, the surfperches exhibit a number of mechanistic similarities which probably characterize the family. The timings of kinematic events and the maximal excursions of the fin tip, as well as the temporal order of muscle activation and the time to peak activity, are largely conserved. The predominant dorsoventral component of fin movement during the stride is consistent with a lift-based mechanism of propulsion. E. lateralis exhibits a greater anteroposterior range of motion and a more continuous period of fine motor control of the fin than A. rhodoterus, differences which may correspond to the species' respective capacities for maneuvering. Mechanistic variation in the family is associated with rather minor structural differences (in fin shape and fin base orientation). Owing to the similar functional demands placed on the pectoral fins of many fishes, it is probable that the mechanistic details of embiotociform swimming are widely distributed within the Perciformes.

Functional Morphology of Aquatic Flight in Fishes: Kinematics, Electromyography, and Mechanical Modeling of Labriform Locomotion

Synopsis. Labriform locomotion is the primary swimming mode for many fishes that use the pectoral fins to generate thrust across a broad range of speeds. A review of the literature on hydrodynamics, kinematics, and morphology of pectoral fin mechanisms in fishes reveals that we lack several kinds of morphological and kinematic data that are critical for understanding thrust generation in this mode, particularly at higher velocities. Several needs include detailed three-dimensional kinematic data on species that are pectoral fin swimmers across a broad range of speeds, data on the motor patterns of pectoral fin muscles, and the development of a mechanical model of pectoral fin functional morphology. New data are presented here on pectoral fin locomotion in Gomphosus varius, a labrid fish that uses the pectoral fins at speeds of 1-6 total body lengths per second. Three-dimensional kinematic data for the pectoral fins of G. varius show that a typical drag-based mechanism is not used in this species. Instead, the thrust mechanics of this fish are dominated by lift forces and acceleration reaction forces. The fin is twisted like a propeller during the fin stroke, so that angles of attack are variable along the fin length. Electromyographic data on six fin muscles indicate the sequence of muscle activity that produces antagonistic fin abduction and adduction and controls the leading edge of the fin. EMG activity in abductors and adductors is synchronous with the start of abduction and adduction, re? spectively, so that muscle mechanics actuate the fin with positive work. A mechanical model of the pectoral fin is proposed in which fin morphometrics and computer simulations allow predictions of fin kinematics in three dimensions. The transmission of force and motion to the leading edge of the fin depends on the mechanical advantage of fin ray levers. An integrative program of research is suggested that will synthesize data on morphology, physiology, kinematics, and hydrodynamics to under? stand the mechanics of pectoral fin swimming.

Pectoral fin locomotion in the striped surfperch. I. Kinematic effects of swimming speed and body size

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 0.35&shy;0.40 SL. Pectoral fin locomotion was supplemented by intermittent caudal fin undulation as swimming speed increased. At the pectoral&shy;caudal 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.

振動翼推進に関する研究

The purpose of this paper is to study the problem which a propulsion method by fin stroke like fish and dolphins is practically applied to the propulsive system of ships. The Fin Ship, which mounts a dolphin-style oscillating wing apparatus under the bottom of the ship, is made for trial and a feasibility test from the engineering stand-point is carried out.The Fin Ship has the following merits; it is free from rolling and pitching of the ship; the danger of one being involved into the rotating screw can be eliminated; contamination of water resulting from the screw stirring up water can be prevented; the propulsive efficiency which gives about 66% in low frequency range is high compared with that of conventional small propellers.It is found that this new propulsion system has great possibility to be applied for low speed ships.

On the Interrelationships Between Morphology and Movement in the Tail of the Cichlid Fish Tilapia Nilotica (L.)

1. An account is given of the morphological structures in the tail region of the \typical fish Tilapia nilotica (fam. Cichlidae), emphasizing the mechanical properties of the caudal skeleton, the vertical septum, the joints between the fin rays and the body, the muscles and tendons and the skin fascia. Two large cartilaginous plates, situated in the vertical septum, are described for the first time. 2. Detailed descriptions of the transformations of the caudal peduncle and fin during short series of lateral undulations of the body and fin are presented. 3. Mutual comparisons of the morphological descriptions with the descriptions of the movements show how structures in the tail are suited to the transfer of propulsive forces, generated by the oscillating tail fin, from the fin to the body. The way structures transfer oscillating movements from the body to the fin and the way muscle activity and several properties of the joints are able to affect the final form of the fin stroke are discussed. 4. A brief account is given of electromyographic data collected and of some problems concerning the use of electromyography in the tail region. 5. It is suggested that the skin fascia collaborates with the myotomes and myosepts to bend the body and the fin. ... Zie Summary