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Sample records for fish swimming mechanics

  1. Fish Swimming: Patternsin the Mechanical Energy Generation, Transmission and Dissipation from Muscle Activation to Body Movement

    NASA Astrophysics Data System (ADS)

    Zhang, W.; Yu, Y. L.; Tong, B. G.

    2011-09-01

    The power consumption of the undulatory fish swimming is produced by active muscles. The mechanical energy generated by stimulated muscles is dissipated partly by the passive tissues of fish while it is being transmitted to the fluid medium. Furthermore, the effective energy, propelling fish movement, is a part of that delivered by the fish body. The process depends on the interactions of the active muscles, the passive tissues, and the water surrounding the fish body. In the previous works, the body-fluid interactions have been investigated widely, but it is rarely considered how the mechanical energy generates, transmits and dissipates in fish swimming. This paper addresses the regular patterns of energy transfer process from muscle activation to body movement for a cruising lamprey (LAMPREY), a kind of anguilliform swimmer. It is necessary to propose a global modelling of the kinematic chain, which is composed of active muscle force-moment model, fish-body dynamic model and hydrodynamic model in order. The present results show that there are traveling energy waves along the fish body from anterior to posterior, accompanied with energy storing and dissipating due to the viscoelastic property of internal tissues. This study is a preliminary research on the framework of kinematic chain coordination performance in fish swimming.

  2. A fish-like robot: Mechanics of swimming due to constraints

    NASA Astrophysics Data System (ADS)

    Tallapragada, Phanindra; Malla, Rijan

    2014-11-01

    It is well known that due to reasons of symmetry, a body with one degree of actuation cannot swim in an ideal fluid. However certain velocity constraints arising in fluid-body interactions, such as the Kutta condition classically applied at the trailing cusp of a Joukowski hydrofoil break this symmetry through vortex shedding. Thus Joukowski foils that vary shape periodically can be shown to be able to swim through vortex shedding. In general it can be shown that vortex shedding due to the Kutta condition is equivalent to nonintegrable constraints arising in the mechanics of finite-dimensional mechanical systems. This equivalence allows hydrodynamic problems involving vortex shedding, especially those pertaining to swimming and related phenomena to be framed in the context of geometric mechanics on manifolds. This formal equivalence also allows the design of bio inspired robots that swim not due to shape change but due to internal moving masses and rotors. Such robots lacking articulated joints are easy to design, build and control. We present such a fish-like robot that swims due to the rotation of internal rotors.

  3. The role of mechanical resonance in the neural control of swimming in fishes

    PubMed Central

    Tytell, Eric D.; Hsu, Chia-Yu; Fauci, Lisa J.

    2014-01-01

    The bodies of many fishes are flexible, elastic structures; if you bend them, they spring back. Therefore, they should have a resonant frequency: a bending frequency at which the output amplitude is maximized for a particular input. Previous groups have hypothesized that swimming at this resonant frequency could maximize efficiency, and that a neural circuit called the central pattern generator might be able to entrain to a mechanical resonance. However, fishes swim in water, which may potentially damp out many resonant effects. Additionally, their bodies are elongated, which means that bending can occur in complicated ways along the length of the body. We review previous studies of the mechanical properties of fish bodies, and then present new data that demonstrate complex bending properties of elongated fish bodies. Resonant peaks in amplitude exist, but there may be many of them depending on the body wavelength. Additionally, they may not correspond to the maximum swimming speed. Next, we describe experiments using a closed-loop preparation of the lamprey, in which a preparation of the spinal cord is linked to a real-time simulation of the muscle and body properties, allowing us to examine resonance entrainment as we vary the simulated resonant frequency. We find that resonance entrainment does occur, but is rare. Gain had a significant, though weak, effect, and a nonlinear muscle model produced resonance entrainment more often than a linear filter. We speculate that resonance may not be a critical effect for efficient swimming in elongate, anguilliform swimmers, though it may be more important for stiffer carangiform and thunniform fishes. PMID:24433627

  4. Where is the rudder of a fish?: the mechanism of swimming and control of self-propelled fish school

    NASA Astrophysics Data System (ADS)

    Wu, Chuijie; Wang, Liang

    2010-03-01

    Numerical simulation and control of self-propelled swimming of two- and three-dimensional biomimetic fish school in a viscous flow are investigated. With a parallel computational fluid dynamics package for the two- and three-dimensional moving boundary problem, which combines the adaptive multi-grid finite volume method and the methods of immersed boundary and volume of fluid, it is found that due to the interactions of vortices in the wakes, without proper control, a fish school swim with a given flapping rule can not keep the fixed shape of a queue. In order to understand the secret of fish swimming, a new feedback control strategy of fish motion is proposed for the first time, i.e., the locomotion speed is adjusted by the flapping frequency of the caudal, and the direction of swimming is controlled by the swinging of the head of a fish. Results show that with this feedback control strategy, a fish school can keep the good order of a queue in cruising, turning or swimming around circles. This new control strategy, which separates the speed control and direction control, is important in the construction of biomimetic robot fish, with which it greatly simplifies the control devices of a biomimetic robot fish.

  5. Prediction of fish body's passive visco-elastic properties and related muscle mechanical performance in vivo during steady swimming

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Yu, YongLiang; Tong, BingGang

    2014-01-01

    For attaining the optimized locomotory performance of swimming fishes, both the passive visco-elastic properties of the fish body and the mechanical behavior of the active muscles should coordinate with the fish body's undulatory motion pattern. However, it is difficult to directly measure the visco-elastic constitutive relation and the muscular mechanical performance in vivo. In the present paper, a new approach based on the continuous beam model for steady swimming fish is proposed to predict the fish body's visco-elastic properties and the related muscle mechanical behavior in vivo. Given the lateral travelling-wave-like movement as the input condition, the required muscle force and the energy consumption are functions of the fish body's visco-elastic parameters, i.e. the Young's modulus E and the viscosity coefficient µ in the Kelvin model. After investigating the variations of the propagating speed of the required muscle force with the fish body's visco-elastic parameters, we analyze the impacts of the visco-elastic properties on the energy efficiencies, including the energy utilization ratios of each element of the kinematic chain in fish swimming and the overall efficiency. Under the constraints of reasonable wave speed of muscle activation and the physiological feasibility, the optimal design of the passive visco-elastic properties can be predicted aiming at maximizing the overall efficiency. The analysis is based on the small-amplitude steady swimming of the carangiform swimmer, with typical Reynolds number varying from 2.5×104 to 2.5×105, and the present results show that the non-dimensional Young's modulus is 112±34, and the non-dimensional viscosity coefficient is 13 approximately. In the present estimated ranges, the overall efficiency of the swimming fish is insensitive to the viscosity, and its magnitude is about 0.11±0.02, in the predicted range given by previous study.

  6. Fish Swimming and Bird/Insect Flight

    NASA Astrophysics Data System (ADS)

    Wu, Theodore Yaotsu

    2011-01-01

    This expository review is devoted to fish swimming and bird/insect flight. (a) The simple waving motion of an elongated flexible ribbon plate of constant width propagating a wave distally down the plate to swim forward in a fluid, initially at rest, is first considered to provide a fundamental concept on energy conservation. It is generalized to include variations in body width and thickness, with appended dorsal, ventral and caudal fins shedding vortices to closely simulate fish swimming, for which a nonlinear theory is presented for large-amplitude propulsion. (b) For bird flight, the pioneering studies on oscillatory rigid wings are discussed with delineating a fully nonlinear unsteady theory for a two-dimensional flexible wing with arbitrary variations in shape and trajectory to provide a comparative study with experiments. (c) For insect flight, recent advances are reviewed by items on aerodynamic theory and modeling, computational methods, and experiments, for forward and hovering flights with producing leading-edge vortex to yield unsteady high lift. (d) Prospects are explored on extracting prevailing intrinsic flow energy by fish and bird to enhance thrust for propulsion. (e) The mechanical and biological principles are drawn together for unified studies on the energetics in deriving metabolic power for animal locomotion, leading to the surprising discovery that the hydrodynamic viscous drag on swimming fish is largely associated with laminar boundary layers, thus drawing valid and sound evidences for a resounding resolution to the long-standing fish-swim paradox proclaimed by Gray (1936, 1968 ).

  7. Emulating a Fish Swim Bladder

    NASA Astrophysics Data System (ADS)

    Vesenka, James; Meredith, Dawn; Bolker, Jessica; Schubert, Christopher; Kraut, Gertrud

    2009-10-01

    The University of New Hampshire and the University of New England are developing biologically relevant physics laboratories for their predominantly health science audiences. Buoyancy plays an important role in a variety of biological processes. We describe an inexpensive laboratory activity based on the Cartesian Diver that allows students to quantitatively emulate the swim bladder of a fish. Inflation of the ``bladder'' is externally controlled through an external gas syringe or squeezing on the plastic water containment vessel (a 2L soda bottle). The students can accurately determine the volume of a ``fish'' at the point of neutral buoyancy by visual measurement of the trapped air pocket. A simple electronic gas pressure sensor allows the hydrostatic pressure on the fish to be analyzed simultaneously.

  8. A mechanism for efficient swimming

    NASA Astrophysics Data System (ADS)

    Haj-Hariri, Hossein; Saadat, Mehdi; Brandes, Aaron; Saraiya, Vishaal; Bart-Smith, Hilary

    2015-11-01

    We present experimental measurements of hydrodynamic performance as well as wake visualization for a freely swimming 3D foil with pure pitching motion. The foil is constrained to move in its axial direction. It is shown that the iso-lines for speed and input power (or economy) coincide in the dimensional frequency versus amplitude plane, up to a critical amplitude. The critical amplitude is independent from swimming speed. It is shown that all swimming gaits (combination of frequency and amplitude) share a single value for Strouhal number (for amplitudes below the critical amplitude), when plotted in non-dimensional frequency vs. amplitude plane. Additionally, it is shown that the swimming gaits with amplitudes equal to the critical amplitude are energetically superior to others. This finding provides a fundamental mechanism for an important observation made by Bainbridge (1958) namely, most fish (such as trout, dace, goldfish, cod and dolphins) maintain constant tail-beat amplitude during cruise, and their speed is correlated linearly with their tail-beat frequency. The results also support prior findings of Saadat and Haj-Hariri (2013). Supported by ONR MURI Grant N00014-14-1-0533.

  9. Swimming Performance of Toy Robotic Fish

    NASA Astrophysics Data System (ADS)

    Petelina, Nina; Mendelson, Leah; Techet, Alexandra

    2015-11-01

    HEXBUG AquaBotsTM are a commercially available small robot fish that come in a variety of ``species''. These models have varying caudal fin shapes and randomly-varied modes of swimming including forward locomotion, diving, and turning. In this study, we assess the repeatability and performance of the HEXBUG swimming behaviors and discuss the use of these toys to develop experimental techniques and analysis methods to study live fish swimming. In order to determine whether these simple, affordable model fish can be a valid representation for live fish movement, two models, an angelfish and a shark, were studied using 2D Particle Image Velocimetry (PIV) and 3D Synthetic Aperture PIV. In a series of experiments, the robotic fish were either allowed to swim freely or towed in one direction at a constant speed. The resultant measurements of the caudal fin wake are compared to data from previous studies of a real fish and simplified flapping propulsors.

  10. Passive elastic mechanism to mimic fish-muscle action in anguilliform swimming

    PubMed Central

    Ramananarivo, Sophie; Godoy-Diana, Ramiro; Thiria, Benjamin

    2013-01-01

    Swimmers in nature use body undulations to generate propulsive and manoeuvring forces. The anguilliform kinematics is driven by muscular actions all along the body, involving a complex temporal and spatial coordination of all the local actuations. Such swimming kinematics can be reproduced artificially, in a simpler way, by using the elasticity of the body passively. Here, we present experiments on self-propelled elastic swimmers at a free surface in the inertial regime. By addressing the fluid–structure interaction problem of anguilliform swimming, we show that our artificial swimmers are well described by coupling a beam theory with the potential flow model of Lighthill. In particular, we show that the propagative nature of the elastic wave producing the propulsive force is strongly dependent on the dissipation of energy along the body of the swimmer. PMID:23985737

  11. Passive elastic mechanism to mimic fish-muscle action in anguilliform swimming.

    PubMed

    Ramananarivo, Sophie; Godoy-Diana, Ramiro; Thiria, Benjamin

    2013-11-01

    Swimmers in nature use body undulations to generate propulsive and manoeuvring forces. The anguilliform kinematics is driven by muscular actions all along the body, involving a complex temporal and spatial coordination of all the local actuations. Such swimming kinematics can be reproduced artificially, in a simpler way, by using the elasticity of the body passively. Here, we present experiments on self-propelled elastic swimmers at a free surface in the inertial regime. By addressing the fluid-structure interaction problem of anguilliform swimming, we show that our artificial swimmers are well described by coupling a beam theory with the potential flow model of Lighthill. In particular, we show that the propagative nature of the elastic wave producing the propulsive force is strongly dependent on the dissipation of energy along the body of the swimmer. PMID:23985737

  12. Swimming and other activities: applied aspects of fish swimming performance

    USGS Publications Warehouse

    Castro-Santos, Theodore R.

    2011-01-01

    Human activities such as hydropower development, water withdrawals, and commercial fisheries often put fish species at risk. Engineered solutions designed to protect species or their life stages are frequently based on assumptions about swimming performance and behaviors. In many cases, however, the appropriate data to support these designs are either unavailable or misapplied. This article provides an overview of the state of knowledge of fish swimming performance – where the data come from and how they are applied – identifying both gaps in knowledge and common errors in application, with guidance on how to avoid repeating mistakes, as well as suggestions for further study.

  13. Towards direct numerical simulation of freely swimming fish.

    NASA Astrophysics Data System (ADS)

    Curet, Oscar; Patankar, Neelesh; Maciver, Malcolm

    2006-11-01

    Swimming mechanisms employed by fish are currently inspiring unique underwater vehicles and robotic devices as well as basic science research into the neural control of movement. Key engineering issues include propulsion efficiency, precise motion control and maneuverability. A numerical scheme that simulates the motion of freely swimming fish will be a valuable design and research tool. We are working towards this goal. In particular we are interested in simulating the motion of a gymnotiform fish that swims by producing undulations of a ventral ribbon fin while keeping its body rigid. We model the fish as a rigid body with an attached undulating membrane. In our numerical scheme the key idea is to assume that the entire fluid-fish domain is a fluid. Then we impose two constraints: the first requires that the fluid in the region occupied by the fish body moves rigidly (a fictitious domain approach), and the second requires that the fluid at the location of the fin has the traveling wave velocity of the fin (an immersed boundary approach). Given the traveling wave form of the fin, the objective is for the numerical scheme to give the swimming velocity of the fish by solving the coupled fluid-fish problem. We will present results for the forces generated by a fin attached to a fixed body and preliminary results for freely swimming fish.

  14. Investigation of flow mechanism of a robotic fish swimming by using flow visualization synchronized with hydrodynamic force measurement

    NASA Astrophysics Data System (ADS)

    Tan, Guang-Kun; Shen, Gong-Xin; Huang, Shuo-Qiao; Su, Wen-Han; Ke, Yu

    When swimming in water by flapping its tail, a fish can overcome the drag from uniform flow and propel its body. The involved flow mechanism concerns 3-D and unsteady effects. This paper presents the investigation of the flow mechanism on the basis of a 3-D robotic fish model which has the typical geometry of body and tail with periodic flapping 2-freedom kinematical motion testing in the case of St = 0.78, Re = 6,600 and phase delay mode (φ = - 75°), in which may have a greater or maximum propulsion (without consideration of the optimal efficiency). Using a special technique of dye visualization which can clearly show vortex sheet and vortices in detail and using the inner 3-component force balance and cable supporting system with the phase-lock technique, the 3-D flow structure visualized in the wake of fish and the hydrodynamic force measurement were synchronized and obtained. Under the mentioned flapping parameters, we found the key flow structure and its evolution, a pair of complex 3-D chain-shape vortex (S-H vortex-rings, S1 - H1 and S2 - H2, and their legs L1 and L2) flow structures, which attach the leading edge and the trailing edge, then shed, move downstream and outwards and distribute two antisymmetric staggering arrays along with the wake of the fish model in different phase stages during the flapping period. It is different with in the case of St = 0.25-0.35. Its typical flow structure and evolution are described and the results prove that they are different from the viewpoints based on the investigation of 2-D cases. For precision of the dynamic force measurement, in this paper it was provided with the method and techniques by subtracting the inertial forces and the forces induced by buoyancy and gravity effect in water, etc. from original data measured. The evolution of the synchronized measuring forces directly matching with the flow structure was also described in this paper.

  15. Investigation of flow mechanism of a robotic fish swimming by using flow visualization synchronized with hydrodynamic force measurement

    NASA Astrophysics Data System (ADS)

    Tan, Guang-Kun; Shen, Gong-Xin; Huang, Shuo-Qiao; Su, Wen-Han; Ke, Yu

    2007-11-01

    When swimming in water by flapping its tail, a fish can overcome the drag from uniform flow and propel its body. The involved flow mechanism concerns 3-D and unsteady effects. This paper presents the investigation of the flow mechanism on the basis of a 3-D robotic fish model which has the typical geometry of body and tail with periodic flapping 2-freedom kinematical motion testing in the case of St = 0.78, Re = 6,600 and phase delay mode ( φ = -75°), in which may have a greater or maximum propulsion (without consideration of the optimal efficiency). Using a special technique of dye visualization which can clearly show vortex sheet and vortices in detail and using the inner 3-component force balance and cable supporting system with the phase-lock technique, the 3-D flow structure visualized in the wake of fish and the hydrodynamic force measurement were synchronized and obtained. Under the mentioned flapping parameters, we found the key flow structure and its evolution, a pair of complex 3-D chain-shape vortex (S-H vortex-rings, S1-H1 and S2-H2, and their legs L1 and L2) flow structures, which attach the leading edge and the trailing edge, then shed, move downstream and outwards and distribute two anti-symmetric staggering arrays along with the wake of the fish model in different phase stages during the flapping period. It is different with in the case of St = 0.25-0.35. Its typical flow structure and evolution are described and the results prove that they are different from the viewpoints based on the investigation of 2-D cases. For precision of the dynamic force measurement, in this paper it was provided with the method and techniques by subtracting the inertial forces and the forces induced by buoyancy and gravity effect in water, etc. from original data measured. The evolution of the synchronized measuring forces directly matching with the flow structure was also described in this paper.

  16. Experimental hydrodynamics of swimming in fishes

    NASA Astrophysics Data System (ADS)

    Tytell, Eric Daniel

    2005-11-01

    The great diversity of fish body shapes suggests that they have adapted to different selective pressures. For many fishes, the pressures include hydrodynamic demands: swimming efficiently or accelerating rapidly, for instance. However, the hydrodynamic advantages or disadvantages to specific morphologies are poorly understood. In particular, eels have been considered inefficient swimmers, but they migrate long distances without feeding, a task that requires efficient swimming. This dissertation, therefore, begins with an examination of the swimming hydrodynamics of American eels, Anguilla rostrata, at steady swimming speeds from 0.5 to 2 body lengths (L) per second and during accelerations from -1.4 to 1.3 L s -2. The final chapter examines the hydrodynamic effects of body shape directly by describing three-dimensional flow around swimming bluegill sunfish, Lepomis macrochirus. In all chapters, flow is quantified using digital particle image velocimetry, and simultaneous kinematics are measured from high-resolution digital video. The wake behind a swimming eel in the horizontal midline plane is described first. Rather than producing a wake with fluid jets angled backwards, like in fishes such as sunfish, eels have a wake with exclusively lateral jets. The lack of downstream momentum indicates that eels balance the axial forces of thrust and drag evenly over time and over their bodies, and therefore do not change axial fluid momentum. This even balance, present at all steady swimming speeds, is probably due to the relatively uniform body shape of eels. As eels accelerate, thrust exceeds drag, axial momentum increases, and the wake approaches that of other fishes. During steady swimming, though, the lack of axial momentum prevents direct efficiency estimation. The effect of body shape was examined directly by measuring flow in multiple transverse planes along the body of bluegill sunfish swimming at 1.2 L s-1. The dorsal and anal fin, neglected in many previous

  17. Analytical insights into optimality and resonance in fish swimming

    PubMed Central

    Kohannim, Saba; Iwasaki, Tetsuya

    2014-01-01

    This paper provides analytical insights into the hypothesis that fish exploit resonance to reduce the mechanical cost of swimming. A simple body–fluid fish model, representing carangiform locomotion, is developed. Steady swimming at various speeds is analysed using optimal gait theory by minimizing bending moment over tail movements and stiffness, and the results are shown to match with data from observed swimming. Our analysis indicates the following: thrust–drag balance leads to the Strouhal number being predetermined based on the drag coefficient and the ratio of wetted body area to cross-sectional area of accelerated fluid. Muscle tension is reduced when undulation frequency matches resonance frequency, which maximizes the ratio of tail-tip velocity to bending moment. Finally, hydrodynamic resonance determines tail-beat frequency, whereas muscle stiffness is actively adjusted, so that overall body–fluid resonance is exploited. PMID:24430125

  18. Shape optimization of the caudal fin of the three-dimensional self-propelled swimming fish

    NASA Astrophysics Data System (ADS)

    Xin, ZhiQiang; Wu, ChuiJie

    2013-02-01

    Shape optimization of the caudal fin of the three-dimensional self-propelled swimming fish, to increase the swimming efficiency and the swimming speed and control the motion direction more easily, is investigated by combining optimization algorithms, unsteady computational fluid dynamics and dynamic control in this study. The 3D computational fluid dynamics package contains the immersed boundary method, volume of fluid method, the adaptive multi-grid finite volume method and the control strategy of fish swimming. Through shape optimizations of various swimming speeds, the results show that the optimal caudal fins of different swimming modes are not exactly the same shape. However, the optimal fish of high swimming speed, whose caudal fin shape is similar to the crescent, also have higher efficiency and better maneuverability than the other optimal bionic fish at low and moderate swimming speeds. Finally, the mechanisms of vorticity creation of different optimal bionic fish are studied by using boundary vorticity-flux theory, and three-dimensional wake structures of self-propelled swimming of these fish are comparatively analyzed. The study of vortex dynamics reveals the nature of efficient swimming of the 3D bionic fish with the lunate caudal fin.

  19. Hydrokinetic turbine effects on fish swimming behaviour.

    PubMed

    Hammar, Linus; Andersson, Sandra; Eggertsen, Linda; Haglund, Johan; Gullström, Martin; Ehnberg, Jimmy; Molander, Sverker

    2013-01-01

    Hydrokinetic turbines, targeting the kinetic energy of fast-flowing currents, are under development with some turbines already deployed at ocean sites around the world. It remains virtually unknown as to how these technologies affect fish, and rotor collisions have been postulated as a major concern. In this study the effects of a vertical axis hydrokinetic rotor with rotational speeds up to 70 rpm were tested on the swimming patterns of naturally occurring fish in a subtropical tidal channel. Fish movements were recorded with and without the rotor in place. Results showed that no fish collided with the rotor and only a few specimens passed through rotor blades. Overall, fish reduced their movements through the area when the rotor was present. This deterrent effect on fish increased with current speed. Fish that passed the rotor avoided the near-field, about 0.3 m from the rotor for benthic reef fish. Large predatory fish were particularly cautious of the rotor and never moved closer than 1.7 m in current speeds above 0.6 ms(-1). The effects of the rotor differed among taxa and feeding guilds and it is suggested that fish boldness and body shape influenced responses. In conclusion, the tested hydrokinetic turbine rotor proved non-hazardous to fish during the investigated conditions. However, the results indicate that arrays comprising multiple turbines may restrict fish movements, particularly for large species, with possible effects on habitat connectivity if migration routes are exploited. Arrays of the investigated turbine type and comparable systems should therefore be designed with gaps of several metres width to allow large fish to pass through. In combination with further research the insights from this study can be used for guiding the design of hydrokinetic turbine arrays where needed, so preventing ecological impacts. PMID:24358334

  20. Hydrokinetic Turbine Effects on Fish Swimming Behaviour

    PubMed Central

    Hammar, Linus; Andersson, Sandra; Eggertsen, Linda; Haglund, Johan; Gullström, Martin; Ehnberg, Jimmy; Molander, Sverker

    2013-01-01

    Hydrokinetic turbines, targeting the kinetic energy of fast-flowing currents, are under development with some turbines already deployed at ocean sites around the world. It remains virtually unknown as to how these technologies affect fish, and rotor collisions have been postulated as a major concern. In this study the effects of a vertical axis hydrokinetic rotor with rotational speeds up to 70 rpm were tested on the swimming patterns of naturally occurring fish in a subtropical tidal channel. Fish movements were recorded with and without the rotor in place. Results showed that no fish collided with the rotor and only a few specimens passed through rotor blades. Overall, fish reduced their movements through the area when the rotor was present. This deterrent effect on fish increased with current speed. Fish that passed the rotor avoided the near-field, about 0.3 m from the rotor for benthic reef fish. Large predatory fish were particularly cautious of the rotor and never moved closer than 1.7 m in current speeds above 0.6 ms-1. The effects of the rotor differed among taxa and feeding guilds and it is suggested that fish boldness and body shape influenced responses. In conclusion, the tested hydrokinetic turbine rotor proved non-hazardous to fish during the investigated conditions. However, the results indicate that arrays comprising multiple turbines may restrict fish movements, particularly for large species, with possible effects on habitat connectivity if migration routes are exploited. Arrays of the investigated turbine type and comparable systems should therefore be designed with gaps of several metres width to allow large fish to pass through. In combination with further research the insights from this study can be used for guiding the design of hydrokinetic turbine arrays where needed, so preventing ecological impacts. PMID:24358334

  1. Swimming behavior of larval Medaka fish under microgravity

    NASA Astrophysics Data System (ADS)

    Furukawa, R.; Ijiri, K.

    Fish exhibit looping and rolling behaviors when subjected to short periods of microgravity during parabolic flight. Strain-differences in the behavioral response of adult Medaka fish ( Oryzias latipes) were reported previously, however, there have been few studies of larval fish behavior under microgravity. In the present study, we investigated whether microgravity affects the swimming behavior of larvae at various ages (0 to 20 days after hatching), using different strains: HNI-II, HO5, ha strain, and variety of different strains (variety). The preliminary experiments were done in the ground laboratory: the development of eyesight was examined using optokinetic response for the different strains. The visual acuity of larvae improved drastically during 20 days after hatching. Strain differences of response were noted for the development of their visual acuity. In microgravity, the results were significantly different from those of adult Medaka. The larval fish appeared to maintain their orientation, except that a few of them exhibited looping and rolling behavior. Further, most larvae swam normally with their backs turning toward the light source (dorsal light response, DLR), and the rest of them stayed with their abdomen touching the surface of the container (ventral substrate response, VSR). For larval stages, strain-differences and age-differences in behavior were observed, but less pronounced than with adult fish under microgravity. Our observations suggest that adaptability of larval fish to the gravitational change and the mechanism of their postural control in microgravity are more variable than in adult fish.

  2. Synthetic C-start maneuver in fish-like swimming

    NASA Astrophysics Data System (ADS)

    Zenit, R.; Godoy-Diana, R.

    2013-11-01

    We investigate the mechanics of the unsteady fish-like swimming maneuver using a simplified experimental model in a water tank. A flexible foil (which emulates the fish body) is impulsively actuated by rotating a cylindrical rod that holds the foil. This rod constitutes the head of the swimmer and is mounted through the shaft of the driving motor on an rail with an air bearing. The foil is initially positioned at a start angle and then rapidly rotated to a final angle, which coincides with the free-moving direction of the rail. As the foil rotates, it pushes the surrounding fluid, it deforms and stores elastic energy which drive the recovery of the straight body shape after the motor actuation has stopped; during the rotation, a trust force is induced which accelerates the array. We measure the resulting escape velocity and acceleration as a function of the beam stiffness, size, initial angle, etc. Some measurements of the velocity field during the escape were obtained using a PIV technique. The measurements agree well with a simple mechanical model that quantifies the impulse of the maneuver. The objective of this work is to understand the fundamental mechanisms of thrust generation in unsteady fast-start swimming. We acknowledge support of EADS Foundation through the project ``Fluids and elasticity in biomimetic propulsion'' and of the Chaire Total for RZ as a visiting professor at ESPCI ParisTech.

  3. Resolving shifting patterns of muscle energy use in swimming fish.

    PubMed

    Gerry, Shannon P; Ellerby, David J

    2014-01-01

    Muscle metabolism dominates the energy costs of locomotion. Although in vivo measures of muscle strain, activity and force can indicate mechanical function, similar muscle-level measures of energy use are challenging to obtain. Without this information locomotor systems are essentially a black box in terms of the distribution of metabolic energy. Although in situ measurements of muscle metabolism are not practical in multiple muscles, the rate of blood flow to skeletal muscle tissue can be used as a proxy for aerobic metabolism, allowing the cost of particular muscle functions to be estimated. Axial, undulatory swimming is one of the most common modes of vertebrate locomotion. In fish, segmented myotomal muscles are the primary power source, driving undulations of the body axis that transfer momentum to the water. Multiple fins and the associated fin muscles also contribute to thrust production, and stabilization and control of the swimming trajectory. We have used blood flow tracers in swimming rainbow trout (Oncorhynchus mykiss) to estimate the regional distribution of energy use across the myotomal and fin muscle groups to reveal the functional distribution of metabolic energy use within a swimming animal for the first time. Energy use by the myotomal muscle increased with speed to meet thrust requirements, particularly in posterior myotomes where muscle power outputs are greatest. At low speeds, there was high fin muscle energy use, consistent with active stability control. As speed increased, and fins were adducted, overall fin muscle energy use declined, except in the caudal fin muscles where active fin stiffening is required to maintain power transfer to the wake. The present data were obtained under steady-state conditions which rarely apply in natural, physical environments. This approach also has potential to reveal the mechanical factors that underlie changes in locomotor cost associated with movement through unsteady flow regimes. PMID:25165858

  4. Resolving Shifting Patterns of Muscle Energy Use in Swimming Fish

    PubMed Central

    Gerry, Shannon P.; Ellerby, David J.

    2014-01-01

    Muscle metabolism dominates the energy costs of locomotion. Although in vivo measures of muscle strain, activity and force can indicate mechanical function, similar muscle-level measures of energy use are challenging to obtain. Without this information locomotor systems are essentially a black box in terms of the distribution of metabolic energy. Although in situ measurements of muscle metabolism are not practical in multiple muscles, the rate of blood flow to skeletal muscle tissue can be used as a proxy for aerobic metabolism, allowing the cost of particular muscle functions to be estimated. Axial, undulatory swimming is one of the most common modes of vertebrate locomotion. In fish, segmented myotomal muscles are the primary power source, driving undulations of the body axis that transfer momentum to the water. Multiple fins and the associated fin muscles also contribute to thrust production, and stabilization and control of the swimming trajectory. We have used blood flow tracers in swimming rainbow trout (Oncorhynchus mykiss) to estimate the regional distribution of energy use across the myotomal and fin muscle groups to reveal the functional distribution of metabolic energy use within a swimming animal for the first time. Energy use by the myotomal muscle increased with speed to meet thrust requirements, particularly in posterior myotomes where muscle power outputs are greatest. At low speeds, there was high fin muscle energy use, consistent with active stability control. As speed increased, and fins were adducted, overall fin muscle energy use declined, except in the caudal fin muscles where active fin stiffening is required to maintain power transfer to the wake. The present data were obtained under steady-state conditions which rarely apply in natural, physical environments. This approach also has potential to reveal the mechanical factors that underlie changes in locomotor cost associated with movement through unsteady flow regimes. PMID:25165858

  5. Locomotion Performance of Biomimetic Fish-like Swimming Devices

    NASA Astrophysics Data System (ADS)

    Epps, Brenden P.; Valdivia Y Alvarado, Pablo; Techet, Alexandra H.

    2007-11-01

    The swimming performance of a biomimetic, fish-like swimming device, designed to exploit the natural dynamics of its compliant body to achieve locomotion, is studied experimentally. A theoretical model combines beam-bending stress analysis and unsteady hydrodynamic forcing with known material properties of the robot to reveal desired geometry distributions and actuation modes. Swimming kinematics and corresponding performance of the device are also predicted and tested for a carangiform prototype device in a quiescent tank of water. Experimental swimming tests show good agreement with the simplified theoretical models. The hydrodynamic characteristics of the wake behind the device are investigated using time-resolved particle imaging velocimetry (PIV) over a range of tail beat frequencies, from 1 to 4 Hz, to asses vortical wake patterns and hydrodynamic forces. PIV data are compared to theoretical model predictions. Reynolds numbers for the swimming device are between 2500 and 8500 based on body length.

  6. THE IPOS FRAMEWORK: LINKING FISH SWIMMING PERFORMANCE IN ALTERED FLOWS FROM LABORATORY EXPERIMENTS TO RIVERS

    SciTech Connect

    Neary, Vincent S

    2011-01-01

    Current understanding of the effects of turbulence on the swimming performance of fish 32 is primarily derived from laboratory experiments under pressurized flow swim tunnels 33 and open channel flow facilities. These studies have produced valuable information on 34 the swimming mechanics and behavior of fish in turbulent flow. However, laboratory 35 studies have limited representation of the flows fish experience in nature. The complex 36 flow structure in rivers is imparted primarily by the highly heterogeneous and non37 uniform bed and planform geometry. Our goal is to direct future laboratory and field 38 studies to adopt a common framework that will shape the integration of both approaches. 39 This paper outlines four characteristics of turbulent flow, which we suggest should be 40 evaluated when generalizing results from fish turbulent studies in both the laboratory and 41 the field. The framework is based on four turbulence characteristics that are summarized 42 under the acronym IPOS: Intensity, Periodicity, Orientation, and Scale.

  7. Swimming performance of a biomimetic compliant fish-like robot

    NASA Astrophysics Data System (ADS)

    Epps, Brenden P.; Valdivia Y Alvarado, Pablo; Youcef-Toumi, Kamal; Techet, Alexandra H.

    2009-12-01

    Digital particle image velocimetry and fluorescent dye visualization are used to characterize the performance of fish-like swimming robots. During nominal swimming, these robots produce a ‘V’-shaped double wake, with two reverse-Kármán streets in the far wake. The Reynolds number based on swimming speed and body length is approximately 7500, and the Strouhal number based on flapping frequency, flapping amplitude, and swimming speed is 0.86. It is found that swimming speed scales with the strength and geometry of a composite wake, which is constructed by freezing each vortex at the location of its centroid at the time of shedding. Specifically, we find that swimming speed scales linearly with vortex circulation. Also, swimming speed scales linearly with flapping frequency and the width of the composite wake. The thrust produced by the swimming robot is estimated using a simple vortex dynamics model, and we find satisfactory agreement between this estimate and measurements made during static load tests.

  8. The hydrodynamics of flexible-body manoeuvres in swimming fish

    NASA Astrophysics Data System (ADS)

    Singh, Kiran; Pedley, Timothy J.

    2008-08-01

    Swimming in flexible-bodied animals like fish is characterised by a travelling wave passing along the spinal chord of the body. Symmetric transverse undulations of the body generate thrust and propel the fish forward. Turns are effected by generating an asymmetric transverse movement of the fish body, frequently as a C-shaped bend. Typical fish swimming speeds allow for simplifying assumptions of incompressible and inviscid flow. The objective of the current work is to use existing theoretical models developed for forward swimming, to analyse fish turns. Lighthill’s classical elongated-body theory for fish swimming forms the fundamental basis for the 3D flow model and ‘recoil’ correction concept implemented here. In the methods developed here, transverse motion of a thin ‘waving’ plate is prescribed by a displacement signal acting along the midline, for finite time to. Lighthill’s approach to calculate the rigid-body motion or ‘recoil’ correction is implemented to ensure zero net force and moments act on the body. Accordingly, angular and transverse motion are computed and final orientation of the plate after the manoeuvre is calculated. A 3D boundary-value algorithm has been developed using a vortex lattice method. The essential methodology, modifications for turning and comparisons with the analytical methods in the small and large aspect ratio limits are presented.

  9. A Study of a Mechanical Swimming Lamprey

    NASA Astrophysics Data System (ADS)

    Leftwich, Megan; Smits, Alexander

    2006-11-01

    To develop a comprehensive model of lamprey swimming, the wake structure generated by a swimming mechanical model is investigated using dye flow visualization. The eel is activated by 13 programmable servomotors and a traveling wave is generated along the length of the body. The waveform is based on the motion of an American eel (Anguilla rostrata) of Tytell and Lauder (2004). A laser scanning system is used to visualize the three-dimensional unsteady wake structure.

  10. Disentangling the Functional Roles of Morphology and Motion in the Swimming of Fish

    PubMed Central

    Tytell, Eric D.; Borazjani, Iman; Sotiropoulos, Fotis; Baker, T. Vernon; Anderson, Erik J.; Lauder, George V.

    2010-01-01

    In fishes the shape of the body and the swimming mode generally are correlated. Slender-bodied fishes such as eels, lampreys, and many sharks tend to swim in the anguilliform mode, in which much of the body undulates at high amplitude. Fishes with broad tails and a narrow caudal peduncle, in contrast, tend to swim in the carangiform mode, in which the tail undulates at high amplitude. Such fishes also tend to have different wake structures. Carangiform swimmers generally produce two staggered vortices per tail beat and a strong downstream jet, while anguilliform swimmers produce a more complex wake, containing at least two pairs of vortices per tail beat and relatively little downstream flow. Are these differences a result of the different swimming modes or of the different body shapes, or both? Disentangling the functional roles requires a multipronged approach, using experiments on live fishes as well as computational simulations and physical models. We present experimental results from swimming eels (anguilliform), bluegill sunfish (carangiform), and rainbow trout (subcarangiform) that demonstrate differences in the wakes and in swimming performance. The swimming of mackerel and lamprey was also simulated computationally with realistic body shapes and both swimming modes: the normal carangiform mackerel and anguilliform lamprey, then an anguilliform mackerel and carangiform lamprey. The gross structure of simulated wakes (single versus double vortex row) depended strongly on Strouhal number, while body shape influenced the complexity of the vortex row, and the swimming mode had the weakest effect. Performance was affected even by small differences in the wakes: both experimental and computational results indicate that anguilliform swimmers are more efficient at lower swimming speeds, while carangiform swimmers are more efficient at high speed. At high Reynolds number, the lamprey-shaped swimmer produced a more complex wake than the mackerel-shaped swimmer

  11. Disentangling the functional roles of morphology and motion in the swimming of fish.

    PubMed

    Tytell, Eric D; Borazjani, Iman; Sotiropoulos, Fotis; Baker, T Vernon; Anderson, Erik J; Lauder, George V

    2010-12-01

    In fishes the shape of the body and the swimming mode generally are correlated. Slender-bodied fishes such as eels, lampreys, and many sharks tend to swim in the anguilliform mode, in which much of the body undulates at high amplitude. Fishes with broad tails and a narrow caudal peduncle, in contrast, tend to swim in the carangiform mode, in which the tail undulates at high amplitude. Such fishes also tend to have different wake structures. Carangiform swimmers generally produce two staggered vortices per tail beat and a strong downstream jet, while anguilliform swimmers produce a more complex wake, containing at least two pairs of vortices per tail beat and relatively little downstream flow. Are these differences a result of the different swimming modes or of the different body shapes, or both? Disentangling the functional roles requires a multipronged approach, using experiments on live fishes as well as computational simulations and physical models. We present experimental results from swimming eels (anguilliform), bluegill sunfish (carangiform), and rainbow trout (subcarangiform) that demonstrate differences in the wakes and in swimming performance. The swimming of mackerel and lamprey was also simulated computationally with realistic body shapes and both swimming modes: the normal carangiform mackerel and anguilliform lamprey, then an anguilliform mackerel and carangiform lamprey. The gross structure of simulated wakes (single versus double vortex row) depended strongly on Strouhal number, while body shape influenced the complexity of the vortex row, and the swimming mode had the weakest effect. Performance was affected even by small differences in the wakes: both experimental and computational results indicate that anguilliform swimmers are more efficient at lower swimming speeds, while carangiform swimmers are more efficient at high speed. At high Reynolds number, the lamprey-shaped swimmer produced a more complex wake than the mackerel-shaped swimmer

  12. A Study of a Mechanical Swimming Dolphin

    NASA Astrophysics Data System (ADS)

    Fang, Lilly; Maass, Daniel; Leftwich, Megan; Smits, Alexander

    2007-11-01

    A one-third scale dolphin model was constructed to investigate dolphin swimming hydrodynamics. Design and construction of the model were achieved using body coordinate data from the common dolphin (Delphinus delphis) to ensure geometric similarity. The front two-thirds of the model are rigid and stationary, while an external mechanism drives the rear third. This motion mimics the kinematics of dolphin swimming. Planar laser induced florescence (PLIF) and particle image velocimetry (PIV) are used to study the hydrodynamics of the wake and to develop a vortex skeleton model.

  13. The swimming mechanics of Artemia Salina

    NASA Astrophysics Data System (ADS)

    Ruiz-Angulo, A.; Ramos-Musalem, A. K.; Zenit, R.

    2013-11-01

    An experimental study to analyze the swimming strategy of a small crustacean (Artemia Salina) was conducted. This animal has a series of eleven pairs of paddle-like appendices in its thorax. These legs move in metachronal-wave fashion to achieve locomotion. To quantify the swimming performance, both high speed video recordings of the legs motion and time-resolved PIV measurements of the induced propulsive jet were conducted. Experiments were conducted for both tethered and freely swimming specimens. We found that despite their small size, the propulsion is achieved by an inertial mechanism. An analysis of the efficiency of the leg wave-like motion is presented and discussed. A brief discussion on the mixing capability of the induced flow is also presented.

  14. Effects of altered gravity on the swimming behaviour of fish

    NASA Astrophysics Data System (ADS)

    Hilbig, R.; Anken, R. H.; Sonntag, G.; Höhne, S.; Henneberg, J.; Kretschmer, N.; Rahmann, H.

    Humans taking part in parabolic aircraft flights (PAFs) may suffer from space motion sickness-phenomena (SMS, a kinetosis). It has been argued that SMS during PAFs might not be based on microgravity alone but rather on changing accelerations from 0g to 2g. We test here the hypothesis that PAF-induced kinetosis is based on asymmetric statoliths (i.e., differently weighed statoliths on the right and the left side of the head), with asymmetric inputs to the brain being disclosed at microgravity. Since fish frequently reveal kinetotic behaviour during PAFs (especially so-called spinning movements and looping responses), we investigated (1) whether or not kinetotically swimming fish at microgravity would have a pronounced inner ear otolith asymmetry and (2) whether or not slow translational and continuously changing linear (vertical) acceleration on ground induced kinetosis. These latter accelerations were applied using a specially developed parabel-animal-container (PAC) to stimulate the cupular organs. The results suggest that the fish tested on ground can counter changing accelerations successfully without revealing kinetotic swimming patterns. Kinetosis could only be induced by PAFs. This finding suggests that it is indeed microgravity rather than changing accelerations, which induces kinetosis. Moreover, we demonstrate that fish swimming kinetotically during PAFs correlates with a higher otolith asymmetry in comparison to normally behaving animals in PAFs.

  15. Evolutionarily Stable Strategies for Fecundity and Swimming Speed of Fish.

    PubMed

    Plank, Michael J; Pitchford, Jonathan W; James, Alex

    2016-02-01

    Many pelagic fish species have a life history that involves producing a large number of small eggs. This is the result of a trade-off between fecundity and larval survival probability. There are also trade-offs involving other traits, such as larval swimming speed. Swimming faster increases the average food encounter rate but also increases the metabolic cost. Here we introduce an evolutionary model comprising fecundity and swimming speed as heritable traits. We show that there can be two evolutionary stable strategies. In environments where there is little noise in the food encounter rate, the stable strategy is a low-fecundity strategy with a swimming speed that minimises the mean time taken to reach reproductive maturity. However, in noisy environments, for example where the prey distribution is patchy or the water is turbulent, strategies that optimise mean outcomes are often outperformed by strategies that increase inter-individual variance. We show that, when larval growth rates are unpredictable, a high-fecundity strategy is evolutionarily stable. In a population following this strategy, the swimming speed is higher than would be anticipated by maximising the mean growth rate. PMID:26817756

  16. Modeling the effect of varying swim speeds on fish passage through velocity barriers

    USGS Publications Warehouse

    Castro-Santos, T.

    2006-01-01

    The distance fish can swim through zones of high-velocity flow is an important factor limiting the distribution and conservation of riverine and diadromous fishes. Often, these barriers are characterized by nonuniform flow conditions, and it is likely that fish will swim at varying speeds to traverse them. Existing models used to predict passage success, however, typically include the unrealistic assumption that fish swim at a constant speed regardless of the speed of flow. This paper demonstrates how the maximum distance of ascent through velocity barriers can be estimated from the swim speed-fatigue time relationship, allowing for variation in both swim speed and water velocity.

  17. Velocity measurements around a freely swimming fish using PIV

    NASA Astrophysics Data System (ADS)

    Kamran Siddiqui, M. H.

    2007-01-01

    Two-dimensional velocity fields around a freely swimming goldfish in a vertical plane have been measured using the particle image velocimetry (PIV) technique. A novel scheme has been developed to detect the fish body in each PIV image. The scheme is capable of detecting the bodies of fish and other aquatic animals with multicolour skin and different patterns. In this scheme, the body portions brighter and darker than the background are extracted separately and then combined together to construct the entire body. The velocity fields show that the fins and tail produce jets. Vortices are also observed in the wake region.

  18. Optimum swimming pathways of fish spawning migrations in rivers

    USGS Publications Warehouse

    McElroy, Brandon; DeLonay, Aaron; Jacobson, Robert

    2012-01-01

    Fishes that swim upstream in rivers to spawn must navigate complex fluvial velocity fields to arrive at their ultimate locations. One hypothesis with substantial implications is that fish traverse pathways that minimize their energy expenditure during migration. Here we present the methodological and theoretical developments necessary to test this and similar hypotheses. First, a cost function is derived for upstream migration that relates work done by a fish to swimming drag. The energetic cost scales with the cube of a fish's relative velocity integrated along its path. By normalizing to the energy requirements of holding a position in the slowest waters at the path's origin, a cost function is derived that depends only on the physical environment and not on specifics of individual fish. Then, as an example, we demonstrate the analysis of a migration pathway of a telemetrically tracked pallid sturgeon (Scaphirhynchus albus) in the Missouri River (USA). The actual pathway cost is lower than 105 random paths through the surveyed reach and is consistent with the optimization hypothesis. The implication—subject to more extensive validation—is that reproductive success in managed rivers could be increased through manipulation of reservoir releases or channel morphology to increase abundance of lower-cost migration pathways.

  19. The effects of steady swimming on fish escape performance.

    PubMed

    Anwar, Sanam B; Cathcart, Kelsey; Darakananda, Karin; Gaing, Ashley N; Shin, Seo Yim; Vronay, Xena; Wright, Dania N; Ellerby, David J

    2016-06-01

    Escape maneuvers are essential to the survival and fitness of many animals. Escapes are frequently initiated when an animal is already in motion. This may introduce constraints that alter the escape performance. In fish, escape maneuvers and steady, body caudal fin (BCF) swimming are driven by distinct patterns of curvature of the body axis. Pre-existing muscle activity may therefore delay or diminish a response. To quantify the performance consequences of escaping in flow, escape behavior was examined in bluegill sunfish (Lepomis macrochirus) in both still-water and during steady swimming. Escapes executed during swimming were kinematically less variable than those made in still-water. Swimming escapes also had increased response latencies and lower peak velocities and accelerations than those made in still-water. Performance was also lower for escapes made up rather than down-stream, and a preference for down-stream escapes may be associated with maximizing performance. The constraints imposed by pre-existing motion and flow, therefore, have the potential to shape predator-prey interactions under field conditions by shifting the optimal strategies for both predators and prey. PMID:27161016

  20. Metabolic fuel kinetics in fish: swimming, hypoxia and muscle membranes.

    PubMed

    Weber, Jean-Michel; Choi, Kevin; Gonzalez, Alex; Omlin, Teye

    2016-01-01

    Muscle performance depends on the supply of metabolic fuels and disposal of end-products. Using circulating metabolite concentrations to infer changes in fluxes is highly unreliable because the relationship between these parameters varies greatly with physiological state. Quantifying fuel kinetics directly is therefore crucial to the understanding of muscle metabolism. This review focuses on how carbohydrates, lipids and amino acids are provided to fish muscles during hypoxia and swimming. Both stresses force white muscle to produce lactate at higher rates than it can be processed by aerobic tissues. However, lactate accumulation is minimized because disposal is also strongly stimulated. Exogenous supply shows that trout have a much higher capacity to metabolize lactate than observed during hypoxia or intense swimming. The low density of monocarboxylate transporters and their lack of upregulation with exercise explain the phenomenon of white muscle lactate retention. This tissue operates as a quasi-closed system, where glycogen stores act as an 'energy spring' that alternates between explosive power release during swimming and slow recoil from lactate in situ during recovery. To cope with exogenous glucose, trout can completely suppress hepatic production and boost glucose disposal. Without these responses, glycemia would increase four times faster and reach dangerous levels. The capacity of salmonids for glucoregulation is therefore much better than presently described in the literature. Instead of albumin-bound fatty acids, fish use lipoproteins to shuttle energy from adipose tissue to working muscles during prolonged exercise. Proteins may play an important role in fueling muscle work in fish, but their exact contribution is yet to be established. The membrane pacemaker theory of metabolism accurately predicts general properties of muscle membranes such as unsaturation, but it does not explain allometric patterns of specific fatty acids. Investigations of

  1. Three-dimensional flow structures and vorticity control in fish-like swimming

    NASA Astrophysics Data System (ADS)

    Zhu, Q.; Wolfgang, M. J.; Yue, D. K. P.; Triantafyllou, M. S.

    2002-10-01

    We employ a three-dimensional, nonlinear inviscid numerical method, in conjunction with experimental data from live fish and from a fish-like robotic mechanism, to establish the three-dimensional features of the flow around a fish-like body swimming in a straight line, and to identify the principal mechanisms of vorticity control employed in fish-like swimming. The computations contain no structural model for the fish and hence no recoil correction. First, we show the near-body flow structure produced by the travelling-wave undulations of the bodies of a tuna and a giant danio. As revealed in cross-sectional planes, for tuna the flow contains dominant features resembling the flow around a two-dimensional oscillating plate over most of the length of the fish body. For the giant danio, on the other hand, a mixed longitudinal transverse structure appears along the hind part of the body. We also investigate the interaction of the body-generated vortices with the oscillating caudal fin and with tail-generated vorticity. Two distinct vorticity interaction modes are identified: the first mode results in high thrust and is generated by constructive pairing of body-generated vorticity with same-sign tail-generated vorticity, resulting in the formation of a strong thrust wake; the second corresponds to high propulsive efficiency and is generated by destructive pairing of body-generated vorticity with opposite-sign tail-generated vorticity, resulting in the formation of a weak thrust wake.

  2. Different ossification patterns of intermuscular bones in fish with different swimming modes

    PubMed Central

    Yao, Wenjie; Lv, Yaoping; Gong, Xiaoling; Wu, Jiaming; Bao, Baolong

    2015-01-01

    ABSTRACT Intermuscular bones are found in the myosepta in teleosts. However, there is very little information on the development and ossification of these intermuscular bones. In this study, we performed an in-depth investigation of the ossification process during development in zebrafish (Danio rerio) and Japanese eel (Anguilla japonica). In Japanese eel, a typical anguilliform swimmer, the intermuscular bones ossified predominantly from the anterior to the posterior. By contrast, in the zebrafish, a sub-carangiform or carangiform swimmer, the intermuscular bones ossified predominantly from the posterior to the anterior regions of the fish. Furthermore, tail amputation affected the ossification of the intermuscular bones. The length of the intermuscular bones in the posterior area became significantly shorter in tail-amputated zebrafish and Japanese eels, and both had less active and lower swimming speeds; this indicates that swimming might induce the ossification of the intermuscular bones. Moreover, when a greater length of tail was amputated in the zebrafish, the intermuscular bones became even shorter. Tail amputation affected the length and ossification of intermuscular bones in the anterior part of the fish, close to the head, differently between the two fish: they became significantly shorter in the zebrafish, but did not in the Japanese eel. This might be because tail amputation did not significantly affect the undulations in the anterior of the Japanese eel, especially near the head. This study shows that the ossification of intermuscular bones might be induced through mechanical force loadings that are produced by swimming. PMID:26603470

  3. Optimal swim speeds for traversing velocity barriers: An analysis of volitional high-speed swimming behavior of migratory fishes

    USGS Publications Warehouse

    Castro-Santos, T.

    2005-01-01

    Migrating fish traversing velocity barriers are often forced to swim at speeds greater than their maximum sustained speed (Ums). Failure to select an appropriate swim speed under these conditions can prevent fish from successfully negotiating otherwise passable barriers. I propose a new model of a distance-maximizing strategy for fishes traversing velocity barriers, derived from the relationships between swim speed and fatigue time in both prolonged and sprint modes. The model predicts that fish will maximize traversed distance by swimming at a constant groundspeed against a range of flow velocities, and this groundspeed is equal to the negative inverse of the slope of the swim speed-fatigue time relationship for each mode. At a predictable flow velocity, they should switch from the optimal groundspeed for prolonged mode to that for sprint mode. Data from six migratory fish species (anadromous clupeids: American shad Alosa sapidissima, alewife A. pseudoharengus and blueback herring A. aestivalis; amphidromous: striped bass Morone saxatilis; and potomodromous species: walleye (previously known as Stizostedion vitrium) and white sucker Catostomus commersonii) were used to explore the ability of fish to approximate the predicted distance-maximizing behaviors, as well as the consequences of deviating from the optima. Fish volitionally sprinted up an open-channel flume against fixed flow velocities of 1.5-4.5 m s-1, providing data on swim speeds and fatigue times, as well as their groundspeeds. Only anadromous clupeids selected the appropriate distance-maximizing groundspeed at both prolonged and sprint modes. The other three species maintained groundspeeds appropriate to the prolonged mode, even when they should have switched to the sprint optima. Because of this, these species failed to maximize distance of ascent. The observed behavioral variability has important implications both for distributional limits and fishway design.

  4. Concentration-dependent toxicity effect of SDBS on swimming behavior of freshwater fishes.

    PubMed

    Zhang, Ying; Ma, Jing; Zhou, Siyun; Ma, Fang

    2015-07-01

    Sodium dodecyl benzene sulfonate (SDBS) is a kind of widely used anionic surfactant and its discharge may pose potential risk to the receiving aquatic ecosystem. The aim of our study is to investigate the toxic effect of SDBS on fish swimming behavior quantitatively, followed by examination whether there are significant differences of swimming behavior among applied fish species (i.e. zebra fish (Danio rerio), Japanese medaka (Oryzias latipes) and red carp (Cyprinus carpio)). The swimming speed and vertical position were analyzed after the fish exposed to SDBS aiming to reflect the toxicity of SDBS on fish. Our results showed that the swimming behavior of three fishes was significantly affected by SDBS, although there were slight differences of swimming pattern changes among three fish species when they exposed to the same concentration of SDBS. It could be seen that red carp, one of the native fish species in China, can be used as a model fish to reflect the water quality changes as well as zebra fish and Japanese medaka which are commonly used as model fishes. Our study also illustrated that the swimming behavior monitoring may have a good application prospect in pre-warning of water quality. PMID:26093194

  5. Effects of non-uniform stiffness on the swimming performance of a passively-flexing, fish-like foil model.

    PubMed

    Lucas, Kelsey N; Thornycroft, Patrick J M; Gemmell, Brad J; Colin, Sean P; Costello, John H; Lauder, George V

    2015-10-01

    Simple mechanical models emulating fish have been used recently to enable targeted study of individual factors contributing to swimming locomotion without the confounding complexity of the whole fish body. Yet, unlike these uniform models, the fish body is notable for its non-uniform material properties. In particular, flexural stiffness decreases along the fish's anterior-posterior axis. To identify the role of non-uniform bending stiffness during fish-like propulsion, we studied four foil model configurations made by adhering layers of plastic sheets to produce discrete regions of high (5.5 × 10(-5) Nm(2)) and low (1.9 × 10(-5) Nm(2)) flexural stiffness of biologically-relevant magnitudes. This resulted in two uniform control foils and two foils with anterior regions of high stiffness and posterior regions of low stiffness. With a mechanical flapping foil controller, we measured forces and torques in three directions and quantified swimming performance under both heaving (no pitch) and constant 0° angle of attack programs. Foils self-propelled at Reynolds number 21 000-115 000 and Strouhal number ∼0.20-0.25, values characteristic of fish locomotion. Although previous models have emphasized uniform distributions and heaving motions, the combination of non-uniform stiffness distributions and 0° angle of attack pitching program was better able to reproduce the kinematics of freely-swimming fish. This combination was likewise crucial in maximizing swimming performance and resulted in high self-propelled speeds at low costs of transport and large thrust coefficients at relatively high efficiency. Because these metrics were not all maximized together, selection of the 'best' stiffness distribution will depend on actuation constraints and performance goals. These improved models enable more detailed, accurate analyses of fish-like swimming. PMID:26447541

  6. On burst-and-coast swimming performance in fish-like locomotion.

    PubMed

    Chung, M-H

    2009-09-01

    Burst-and-coast swimming performance in fish-like locomotion is studied via two-dimensional numerical simulation. The numerical method used is the collocated finite-volume adaptive Cartesian cut-cell method developed previously. The NACA00xx airfoil shape is used as an equilibrium fish-body form. Swimming in a burst-and-coast style is computed assuming that the burst phase is composed of a single tail-beat. Swimming efficiency is evaluated in terms of the mass-specific cost of transport instead of the Froude efficiency. The effects of the Reynolds number (based on the body length and burst time), duty cycle and fineness ratio (the body length over the largest thickness) on swimming performance (momentum capacity and the mass-specific cost of transport) are studied quantitatively. The results lead to a conclusion consistent with previous findings that a larval fish seldom swims in a burst-and-coast style. Given mass and swimming speed, a fish needs the least cost if it swims in a burst-and-coast style with a fineness ratio of 8.33. This energetically optimal fineness ratio is larger than that derived from the simple hydromechanical model proposed in literature. The calculated amount of energy saving in burst-and-coast swimming is comparable with the real-fish estimation in the literature. Finally, the predicted wake-vortex structures of both continuous and burst-and-coast swimming are biologically relevant. PMID:19567970

  7. Swimming movements initiate bubble formation in fish decompressed from elevated gas pressures.

    PubMed

    McDonough, P M; Hemmingsen, E A

    1985-01-01

    Young specimens of trout, catfish, sculpin and salamanders were equilibrated with elevated gas pressures, then rapidly decompressed to ambient pressure. The newly hatched forms tolerated extremely high gas supersaturations; equilibration pressures of 80-120 atm argon or 150-250 atm helium were required for in vivo bubble formation. During subsequent larval development, the equilibration pressures required decreased to just 5-10 atm and bubbles originated in the fins. Anesthetising older fish before decompression prevented bubble formation in the fins; this suggests that swimming movements mechanically initiate bubbles, possibly by a tribonucleation mechanism. PMID:2859954

  8. Video tracking method for three-dimensional measurement of a free-swimming fish

    NASA Astrophysics Data System (ADS)

    Wu, Guanhao; Zeng, Lijiang

    2007-12-01

    A video system for tracking a free-swimming fish two-dimensionally is introduced in this paper. The tracking is accomplished by simultaneously taking images from the ventral view and the lateral view of the fish with two CCD cameras mounted on two computer-controlled and mutually orthogonal translation stages. By processing the images recorded during tracking, three-dimensional kinematic parameters of the tail and pectoral fin of the fish in forward, backward and turning swimming modes are obtained.

  9. Go reconfigure: how fish change shape as they swim and evolve.

    PubMed

    Long, John H; Porter, Marianne E; Root, Robert G; Liew, Chun Wai

    2010-12-01

    The bodies of fish change shape over propulsive, behavioral, developmental, and evolutionary time scales, a general phenomenon that we call "reconfiguration". Undulatory, postural, and form-reconfiguration can be distinguished, studied independently, and examined in terms of mechanical interactions and evolutionary importance. Using a combination of live, swimming fishes and digital robotic fish that are autonomous and self-propelled, we examined the functional relation between undulatory and postural reconfiguration in forward swimming, backward swimming, and yaw turning. To probe how postural and form reconfiguration interact, the yaw turning of leopard sharks was examined using morphometric and kinematic analyses. To test how undulatory reconfiguration might evolve, the digital robotic fish were subjected to selection for enhanced performance in a simulated ecology in which each individual had to detect and move towards a food source. In addition to the general issue of reconfiguration, these investigations are united by the fact that the dynamics of undulatory and postural reconfigurations are predicted to be determined, in part, by the structural stiffness of the fish's body. Our method defines undulatory reconfiguration as the combined, point-by-point periodic motion of the body, leaving postural reconfiguration as the combined deviations from undulatory reconfiguration. While undulatory reconfiguration appears to be the sole or primary propulsive driver, postural reconfiguration may contribute to propulsion in hagfish and it is correlated with differences in forward, and backward, swimming in lamprey. Form reconfigures over developmental time in leopard sharks in a manner that is consistent with an allometric scaling theory in which structural stiffness of the body is held constant. However, correlation of a form proxy for structural stiffness of the body suggests that body stiffness may scale in order to limit maximum postural reconfiguration during routine

  10. Passive and Active Flow Control by Swimming Fishes and Mammals

    NASA Astrophysics Data System (ADS)

    Fish, F. E.; Lauder, G. V.

    2006-01-01

    What mechanisms of flow control do animals use to enhance hydrodynamic performance? Animals are capable of manipulating flow around the body and appendages both passively and actively. Passive mechanisms rely on structural and morphological components of the body (i.e., humpback whale tubercles, riblets). Active flow control mechanisms use appendage or body musculature to directly generate wake flow structures or stiffen fins against external hydrodynamic loads. Fish can actively control fin curvature, displacement, and area. The vortex wake shed by the tail differs between eel-like fishes and fishes with a discrete narrowing of the body in front of the tail, and three-dimensional effects may play a major role in determining wake structure in most fishes.

  11. Development of a Transient Acoustic Boundary Element Method to Predict the Noise Signature of Swimming Fish

    NASA Astrophysics Data System (ADS)

    Wagenhoffer, Nathan; Moored, Keith; Jaworski, Justin

    2015-11-01

    Animals have evolved flexible wings and fins to efficiently and quietly propel themselves through the air and water. The design of quiet and efficient bio-inspired propulsive concepts requires a rapid, unified computational framework that integrates three essential features: the fluid mechanics, the elastic structural response, and the noise generation. This study focuses on the development, validation, and demonstration of a transient, two-dimensional acoustic boundary element solver accelerated by a fast multipole algorithm. The resulting acoustic solver is used to characterize the acoustic signature produced by a vortex street advecting over a NACA 0012 airfoil, which is representative of vortex-body interactions that occur in schools of swimming fish. Both 2S and 2P canonical vortex streets generated by fish are investigated over the range of Strouhal number 0 . 2 < St < 0 . 4 , and the acoustic signature of the airfoil is quantified. This study provides the first estimate of the noise signature of a school of swimming fish. Lehigh University CORE Grant.

  12. Flapping flexible fish. Periodic and secular body reconfigurations in swimming lamprey, Petromyzon marinus

    NASA Astrophysics Data System (ADS)

    Root, Robert G.; Courtland, Hayden-William; Shepherd, William; Long, John H.

    2007-11-01

    In order to analyze and model the body kinematics used by fish in a wide range of swimming behaviors, we developed a technique to separate the periodic whole-body motions that characterize steady swimming from the secular motions that characterize changes in whole-body shape. We applied this harmonic analysis technique to the study of the forward and backward swimming of lamprey. We found that in order to vary the unsteadiness of swimming, lamprey superimpose periodic and secular components of their body motion, modulate the patterns and magnitudes of those components, and change shape. These kinematic results suggest the following hydromechanical hypothesis: steady swimming is a maneuver that requires active suppression of secular body reconfigurations.

  13. Quantitative wake analysis of a freely swimming fish using 3D synthetic aperture PIV

    NASA Astrophysics Data System (ADS)

    Mendelson, Leah; Techet, Alexandra H.

    2015-07-01

    Synthetic aperture PIV (SAPIV) is used to quantitatively analyze the wake behind a giant danio ( Danio aequipinnatus) swimming freely in a seeded quiescent tank. The experiment is designed with minimal constraints on animal behavior to ensure that natural swimming occurs. The fish exhibits forward swimming and turning behaviors at speeds between 0.9 and 1.5 body lengths/second. Results show clearly isolated and linked vortex rings in the wake structure, as well as the thrust jet coming off of a visual hull reconstruction of the fish body. As a benchmark for quantitative analysis of volumetric PIV data, the vortex circulation and impulse are computed using methods consistent with those applied to planar PIV data. Volumetric momentum analysis frameworks are discussed for linked and asymmetric vortex structures, laying a foundation for further volumetric studies of swimming hydrodynamics with SAPIV. Additionally, a novel weighted refocusing method is presented as an improvement to SAPIV reconstruction.

  14. Fish locomotion: insights from both simple and complex mechanical models

    NASA Astrophysics Data System (ADS)

    Lauder, George

    2015-11-01

    Fishes are well-known for their ability to swim and maneuver effectively in the water, and recent years have seen great progress in understanding the hydrodynamics of aquatic locomotion. But studying freely-swimming fishes is challenging due to difficulties in controlling fish behavior. Mechanical models of aquatic locomotion have many advantages over studying live animals, including the ability to manipulate and control individual structural or kinematic factors, easier measurement of forces and torques, and the ability to abstract complex animal designs into simpler components. Such simplifications, while not without their drawbacks, facilitate interpretation of how individual traits alter swimming performance and the discovery of underlying physical principles. In this presentation I will discuss the use of a variety of mechanical models for fish locomotion, ranging from simple flexing panels to complex biomimetic designs incorporating flexible, actively moved, fin rays on multiple fins. Mechanical devices have provided great insight into the dynamics of aquatic propulsion and, integrated with studies of locomotion in freely-swimming fishes, provide new insights into how fishes move through the water.

  15. Body Fineness Ratio as a Predictor of Maximum Prolonged-Swimming Speed in Coral Reef Fishes

    PubMed Central

    Walker, Jeffrey A.; Alfaro, Michael E.; Noble, Mae M.; Fulton, Christopher J.

    2013-01-01

    The ability to sustain high swimming speeds is believed to be an important factor affecting resource acquisition in fishes. While we have gained insights into how fin morphology and motion influences swimming performance in coral reef fishes, the role of other traits, such as body shape, remains poorly understood. We explore the ability of two mechanistic models of the causal relationship between body fineness ratio and endurance swimming-performance to predict maximum prolonged-swimming speed (Umax) among 84 fish species from the Great Barrier Reef, Australia. A drag model, based on semi-empirical data on the drag of rigid, submerged bodies of revolution, was applied to species that employ pectoral-fin propulsion with a rigid body at Umax. An alternative model, based on the results of computer simulations of optimal shape in self-propelled undulating bodies, was applied to the species that swim by body-caudal-fin propulsion at Umax. For pectoral-fin swimmers, Umax increased with fineness, and the rate of increase decreased with fineness, as predicted by the drag model. While the mechanistic and statistical models of the relationship between fineness and Umax were very similar, the mechanistic (and statistical) model explained only a small fraction of the variance in Umax. For body-caudal-fin swimmers, we found a non-linear relationship between fineness and Umax, which was largely negative over most of the range of fineness. This pattern fails to support either predictions from the computational models or standard functional interpretations of body shape variation in fishes. Our results suggest that the widespread hypothesis that a more optimal fineness increases endurance-swimming performance via reduced drag should be limited to fishes that swim with rigid bodies. PMID:24204575

  16. Swimming Behavior and Calcium Incorporation into inner Ear Otoliths of Fish after vestibular Nerve Transection

    NASA Astrophysics Data System (ADS)

    Edelmann, E.; Anken, R.; Rahmann, H.

    Previous investigations on neonate swordtail fish (Xiphophorus helleri) revealed that otolithic calcium incorporation (visualized using the calcium-tracer alizarin- complexone) and thus otolith growth had ceased after nerve transection, supporting a hypothesis according to which the gravity-dependent otolith growth is regulated neuronally. Subsequent investigations on larval cichlid fish (Oreochromis mossambicus) yielded contrasting results, repeatedly depending on the particular batch of cichlids investigated: Like neonate swordtails, type I cichlids revealed a stop of calcium incorporation after unilateral vestibular nerve transection. Their behaviour after transection was normal and the otolithic calcium incorporation in controls of the same batch was symmetrical. In type II cichlids, however, vestibular nerve transection had no effect on otolithic calcium incorporation. They behaved kinetotically after transection (this kind of kinetosis was qualitatively similar to the swimming behaviour exhibited by larval cichlids during microgravity in the course of parabolic aircraft flights). The otolithic calcium incorporation in control animals was asymmetrical. These results stongly suggest that the effects of vestibular nerve transection as well as the efficacy of the mechanism, which regulates otolith growth/otolithic calcium incorporation, are - depending on the particular batch of animals - genetically predispositioned. Thus, it is assumed that the mechanisms regulating otolith growth and equlibibrium differ in the two types of cichlid fish. This work was financially supported by the German Aerospace Center (DLR) e.V. (FKZ: 50 WB 9997).

  17. Optimally efficient swimming in hyper-redundant mechanisms: control, design, and energy recovery.

    PubMed

    Wiens, A J; Nahon, M

    2012-12-01

    Hyper-redundant mechanisms (HRMs), also known as snake-like robots, are highly adaptable during locomotion on land. Researchers are currently working to extend their capabilities to aquatic environments through biomimetic undulatory propulsion. In addition to increasing the versatility of the system, truly biomimetic swimming could also provide excellent locomotion efficiency. Unfortunately, the complexity of the system precludes the development of a functional solution to achieve this. To explore this problem, a rapid optimization process is used to generate efficient HRM swimming gaits. The low computational cost of the approach allows for multiple optimizations over a broad range of system conditions. By observing how these conditions affect optimal kinematics, a number of new insights are developed regarding undulatory swimming in robotic systems. Two key conditions are varied within the study, swimming speed and energy recovery. It is found that the swimmer mimics the speed control behaviour of natural fish and that energy recovery drastically increases the system's efficiency. Remarkably, this efficiency increase is accompanied by a distinct change in swimming kinematics. With energy recovery, the swimmer converges to a clearly anguilliform gait, without, it tends towards the carangiform mode. PMID:23135166

  18. Thrust production by a mechanical swimming lamprey

    NASA Astrophysics Data System (ADS)

    Leftwich, M. C.; Smits, A. J.

    2011-05-01

    To develop a comprehensive model of lamprey locomotion, we use a robotic lamprey to investigate the formation of the wake structure, the shedding vorticity from the body, and the relationship between thrust production and pressure on the surface of the robot. The robot mimics the motion of living lamprey in steady swimming by using a programmable microcomputer to actuate 13 servomotors that produce a traveling wave along the length of the lamprey body. The amplitude of the phase-averaged surface pressure distribution along the centerline of the robot increases toward the tail, which is consistent with previous momentum balance experiments. This indicates that thrust is produced mainly at the tail. The phase relationship between the pressure signal and the vortex shedding from the tail is also examined, showing a clear connection between the location of vortex structures and the fluctuations of the pressure signal.

  19. A Study of a Mechanical Swimming Lamprey

    NASA Astrophysics Data System (ADS)

    Leftwich, Megan; Hultmark, Marcus; Smits, Alexander

    2007-11-01

    In order to develop a comprehensive model of lamprey locomotion, we use a swimming robotic lamprey as a means of investigating the surface pressure, thrust and wake structure. A programmable microcomputer actuates 13 servomotors that produce a traveling wave along the length of the lamprey's body. This waveform is based on the motion of the American eel (Anguilla rostrata), as described by Tytell and Lauder (2004). Dye flow visualization and particle image velocimetry (PIV) are used to study the wake structure generated by the robot and the flowfield along the body. These visualization methods show that two distinct, oppositely signed vortices are shed each half cycle; whereas along the body, no large scale vortical shedding can be observed, suggesting that most of the thrust is produced by the tail. Thrust data based on momentum balances support this suggestion. The project is supported by NIH Grant 1RO1NS054271.

  20. Thrust Production in a Mechanical Swimming Lamprey

    NASA Astrophysics Data System (ADS)

    Leftwich, Megan; Smits, Alexander

    2008-11-01

    To develop a comprehensive model of lamprey locomotion, we use a robotic lamprey as a means of investigating the surface pressure and wake structure during swimming. A programmable microcomputer actuates 11 servomotors that produce a traveling wave along the length of the lamprey body. The waveform is based on the motion of the American eel (Anguilla rostrata), as described by Tytell and Lauder (2004) and kinematic studies of living lamprey. The amplitude of the phase-averaged surface pressure distribution along the centerline of the robot increases toward the tail, which is consistent with previous momentum balance experiments indicating that thrust is produced mainly at the tail. The phase relationship between the pressure signal and the vortex shedding from the tail is also examined. The project is supported by NIH CNRS Grant 1R01NS054271.

  1. Fish optimize sensing and respiration during undulatory swimming

    PubMed Central

    Akanyeti, O.; Thornycroft, P. J. M.; Lauder, G. V.; Yanagitsuru, Y. R.; Peterson, A. N.; Liao, J. C.

    2016-01-01

    Previous work in fishes considers undulation as a means of propulsion without addressing how it may affect other functions such as sensing and respiration. Here we show that undulation can optimize propulsion, flow sensing and respiration concurrently without any apparent tradeoffs when head movements are coupled correctly with the movements of the body. This finding challenges a long-held assumption that head movements are simply an unintended consequence of undulation, existing only because of the recoil of an oscillating tail. We use a combination of theoretical, biological and physical experiments to reveal the hydrodynamic mechanisms underlying this concerted optimization. Based on our results we develop a parsimonious control architecture that can be used by both undulatory animals and machines in dynamic environments. PMID:27009352

  2. Mosquitofish (Gambusia affinis) responds differentially to a robotic fish of varying swimming depth and aspect ratio.

    PubMed

    Polverino, Giovanni; Porfiri, Maurizio

    2013-08-01

    In this study, we explore the feasibility of using bioinspired robotics to influence the behaviour of mosquitofish (Gambusia affinis), a social freshwater fish species that is extensively studied for the ecological issues associated with its diffusion in non-native environments. Specifically, in a dichotomous choice test, we investigate the behavioural response of small shoals of mosquitofish to a robotic fish inspired by mosquitofish in its colouration, shape, aspect ratio, and locomotion. Our results indicate that the swimming depth and the aspect ratio of the robotic fish are both determinants of mosquitofish preference. In particular, we find that mosquitofish are never attracted by a robotic fish whose colouration and shape are inspired by live subjects and that the degree of repulsion varies as a function of the swimming depth and the aspect ratio. PMID:23684918

  3. Skating by: low energetic costs of swimming in a batoid fish.

    PubMed

    Di Santo, Valentina; Kenaley, Christopher P

    2016-06-15

    We quantify the oxygen consumption rates and cost of transport (COT) of a benthic batoid fish, the little skate, Leucoraja erinacea, at three swimming speeds. We report that this species has the lowest mass-adjusted swimming metabolic rate measured for any elasmobranch; however, this species incurs a much higher COT at approximately five times the lowest values recorded for some teleosts. In addition, because skates lack a propulsive caudal fin and could not sustain steady swimming beyond a relatively low optimum speed of 1.25 body lengths s(-1), we propose that the locomotor efficiency of benthic rajiform fishes is limited to the descending portion of a single COT-speed relationship. This renders these species poorly suited for long-distance translocation and, therefore, especially vulnerable to regional-scale environmental disturbances. PMID:27080535

  4. Mechanics of Undulatory Swimming in a Frictional Fluid

    PubMed Central

    Ding, Yang; Sharpe, Sarah S.; Masse, Andrew; Goldman, Daniel I.

    2012-01-01

    The sandfish lizard (Scincus scincus) swims within granular media (sand) using axial body undulations to propel itself without the use of limbs. In previous work we predicted average swimming speed by developing a numerical simulation that incorporated experimentally measured biological kinematics into a multibody sandfish model. The model was coupled to an experimentally validated soft sphere discrete element method simulation of the granular medium. In this paper, we use the simulation to study the detailed mechanics of undulatory swimming in a “granular frictional fluid” and compare the predictions to our previously developed resistive force theory (RFT) which models sand-swimming using empirically determined granular drag laws. The simulation reveals that the forward speed of the center of mass (CoM) oscillates about its average speed in antiphase with head drag. The coupling between overall body motion and body deformation results in a non-trivial pattern in the magnitude of lateral displacement of the segments along the body. The actuator torque and segment power are maximal near the center of the body and decrease to zero toward the head and the tail. Approximately 30% of the net swimming power is dissipated in head drag. The power consumption is proportional to the frequency in the biologically relevant range, which confirms that frictional forces dominate during sand-swimming by the sandfish. Comparison of the segmental forces measured in simulation with the force on a laterally oscillating rod reveals that a granular hysteresis effect causes the overestimation of the body thrust forces in the RFT. Our models provide detailed testable predictions for biological locomotion in a granular environment. PMID:23300407

  5. Fish and Robots Swimming Together in a Water Tunnel: Robot Color and Tail-Beat Frequency Influence Fish Behavior

    PubMed Central

    Polverino, Giovanni; Phamduy, Paul; Porfiri, Maurizio

    2013-01-01

    The possibility of integrating bioinspired robots in groups of live social animals may constitute a valuable tool to study the basis of social behavior and uncover the fundamental determinants of animal functions and dysfunctions. In this study, we investigate the interactions between individual golden shiners (Notemigonus crysoleucas) and robotic fish swimming together in a water tunnel at constant flow velocity. The robotic fish is designed to mimic its live counterpart in the aspect ratio, body shape, dimension, and locomotory pattern. Fish positional preference with respect to the robot is experimentally analyzed as the robot's color pattern and tail-beat frequency are varied. Behavioral observations are corroborated by particle image velocimetry studies aimed at investigating the flow structure behind the robotic fish. Experimental results show that the time spent by golden shiners in the vicinity of the bioinspired robotic fish is the highest when the robot mimics their natural color pattern and beats its tail at the same frequency. In these conditions, fish tend to swim at the same depth of the robotic fish, where the wake from the robotic fish is stronger and hydrodynamic return is most likely to be effective. PMID:24204882

  6. Fish and robots swimming together in a water tunnel: robot color and tail-beat frequency influence fish behavior.

    PubMed

    Polverino, Giovanni; Phamduy, Paul; Porfiri, Maurizio

    2013-01-01

    The possibility of integrating bioinspired robots in groups of live social animals may constitute a valuable tool to study the basis of social behavior and uncover the fundamental determinants of animal functions and dysfunctions. In this study, we investigate the interactions between individual golden shiners (Notemigonus crysoleucas) and robotic fish swimming together in a water tunnel at constant flow velocity. The robotic fish is designed to mimic its live counterpart in the aspect ratio, body shape, dimension, and locomotory pattern. Fish positional preference with respect to the robot is experimentally analyzed as the robot's color pattern and tail-beat frequency are varied. Behavioral observations are corroborated by particle image velocimetry studies aimed at investigating the flow structure behind the robotic fish. Experimental results show that the time spent by golden shiners in the vicinity of the bioinspired robotic fish is the highest when the robot mimics their natural color pattern and beats its tail at the same frequency. In these conditions, fish tend to swim at the same depth of the robotic fish, where the wake from the robotic fish is stronger and hydrodynamic return is most likely to be effective. PMID:24204882

  7. Thermal acclimation effects differ between voluntary, maximum, and critical swimming velocities in two cyprinid fishes.

    PubMed

    O'Steen, Shyril; Bennett, Albert F

    2003-01-01

    Temperature acclimation may be a critical component of the locomotor physiology and ecology of ectothermic animals, particularly those living in eurythermal environments. Several studies of fish report striking acclimation of biochemical and kinetic properties in isolated muscle. However, the relatively few studies of whole-animal performance report variable acclimation responses. We test the hypothesis that different types of whole-animal locomotion will respond differently to temperature acclimation, probably due to divergent physiological bases of locomotion. We studied two cyprinid fishes, tinfoil barbs (Puntius schwanenfeldii) and river barbels (Barbus barbus). Study fish were acclimated to either cold or warm temperatures for at least 6 wk and then assayed at four test temperatures for three types of swimming performance. We measured voluntary swimming velocity to estimate routine locomotor behavior, maximum fast start velocity to estimate anaerobic capacity, and critical swimming velocity to estimate primarily aerobic capacity. All three performance measures showed some acute thermal dependence, generally a positive correlation between swimming speed and test temperature. However, each performance measure responded quite differently to acclimation. Critical speeds acclimated strongly, maximum speeds not at all, and voluntary speeds uniquely in each species. Thus we conclude that long-term temperature exposure can have very different consequences for different types of locomotion, consistent with our hypothesis. The data also address previous hypotheses that predict that polyploid and eurythermal fish will have greater acclimation abilities than other fish, due to increased genetic flexibility and ecological selection, respectively. Our results conflict with these predictions. River barbels are eurythermal polyploids and tinfoil barbs stenothermal diploids, yet voluntary swimming acclimated strongly in tinfoil barbs and minimally in river barbels, and

  8. Fish-robot interactions in a free-swimming environment: Effects of speed and configuration of robots on live fish

    NASA Astrophysics Data System (ADS)

    Butail, Sachit; Polverino, Giovanni; Phamduy, Paul; Del Sette, Fausto; Porfiri, Maurizio

    2014-03-01

    We explore fish-robot interactions in a comprehensive set of experiments designed to highlight the effects of speed and configuration of bioinspired robots on live zebrafish. The robot design and movement is inspired by salient features of attraction in zebrafish and includes enhanced coloration, aspect ratio of a fertile female, and carangiform/subcarangiformlocomotion. The robots are autonomously controlled to swim in circular trajectories in the presence of live fish. Our results indicate that robot configuration significantly affects both the fish distance to the robots and the time spent near them.

  9. Swimming behaviour and calcium incorporation into inner ear otoliths of fish after vestibular nerve transection.

    PubMed

    Edelmann, E; Anken, R H; Rahmann, H

    2004-01-01

    Previous investigations on neonate swordtail fish (Xiphophorus helleri) revealed that otolithic calcium incorporation (visualized using the calcium tracer alizarin complexone) and thus otolith growth had ceased after nerve transection, supporting a hypothesis according to which the gravity-dependent otolith growth is regulated neuronally. Subsequent investigations on larval cichlid fish (Oreochromis mossambicus) yielded contrasting results, repeatedly depending on the particular batch of cichlids investigated. Like most neonate swordtails, Type I cichlids revealed a stop of calcium incorporation after unilateral vestibular nerve transection. Their behaviour after transection was normal, and the otolithic calcium incorporation in controls of the same batch was symmetric. In Type II cichlids, however, vestibular nerve transection had no effect on otolithic calcium incorporation. They behaved kinetotically after transection (this kind of kinetosis was qualitatively similar to the swimming behaviour exhibited by larval cichlids during microgravity in the course of parabolic aircraft flights). The otolithic calcium incorporation in control animals was asymmetric. These results show that the effects of vestibular nerve transection as well as the efficacy of the mechanism, which regulates otolith growth/otolithic calcium incorporation, are--depending on the particular batch of animals--genetically predispositioned. In conclusion, the regulation of otolithic calcium incorporation is guided neuronally, in part via the vestibular nerve and, in part, via a further pathway, which remains to be addressed in the course of future investigations. PMID:15803634

  10. Swimming behaviour and calcium incorporation into inner ear otoliths of fish after vestibular nerve transection

    NASA Astrophysics Data System (ADS)

    Edelmann, E.; Anken, R. H.; Rahmann, H.

    2004-01-01

    Previous investigations on neonate swordtail fish (Xiphophorus helleri) revealed that otolithic calcium incorporation (visualized using the calcium tracer alizarin complexone) and thus otolith growth had ceased after nerve transection, supporting a hypothesis according to which the gravity-dependent otolith growth is regulated neuronally. Subsequent investigations on larval cichlid fish (Oreochromis mossambicus) yielded contrasting results, repeatedly depending on the particular batch of cichlids investigated. Like most neonate swordtails, Type I cichlids revealed a stop of calcium incorporation after unilateral vestibular nerve transection. Their behaviour after transection was normal, and the otolithic calcium incorporation in controls of the same batch was symmetric. In Type II cichlids, however, vestibular nerve transection had no effect on otolithic calcium incorporation. They behaved kinetotically after transection (this kind of kinetosis was qualitatively similar to the swimming behaviour exhibited by larval cichlids during microgravity in the course of parabolic aircraft flights). The otolithic calcium incorporation in control animals was asymmetric. These results show that the effects of vestibular nerve transection as well as the efficacy of the mechanism, which regulates otolith growth/otolithic calcium incorporation, are - depending on the particular batch of animals - genetically predispositioned. In conclusion, the regulation of otolithic calcium incorporation is guided neuronally, in part via the vestibular nerve and, in part, via a further pathway, which remains to be addressed in the course of future investigations.

  11. Center of mass motion in swimming fish: effects of speed and locomotor mode during undulatory propulsion.

    PubMed

    Xiong, Grace; Lauder, George V

    2014-08-01

    Studies of center of mass (COM) motion are fundamental to understanding the dynamics of animal movement, and have been carried out extensively for terrestrial and aerial locomotion. But despite a large amount of literature describing different body movement patterns in fishes, analyses of how the center of mass moves during undulatory propulsion are not available. These data would be valuable for understanding the dynamics of different body movement patterns and the effect of differing body shapes on locomotor force production. In the present study, we analyzed the magnitude and frequency components of COM motion in three dimensions (x: surge, y: sway, z: heave) in three fish species (eel, bluegill sunfish, and clown knifefish) swimming with four locomotor modes at three speeds using high-speed video, and used an image cross-correlation technique to estimate COM motion, thus enabling untethered and unrestrained locomotion. Anguilliform swimming by eels shows reduced COM surge oscillation magnitude relative to carangiform swimming, but not compared to knifefish using a gymnotiform locomotor style. Labriform swimming (bluegill at 0.5 body lengths/s) displays reduced COM sway oscillation relative to swimming in a carangiform style at higher speeds. Oscillation frequency of the COM in the surge direction occurs at twice the tail beat frequency for carangiform and anguilliform swimming, but at the same frequency as the tail beat for gymnotiform locomotion in clown knifefish. Scaling analysis of COM heave oscillation for terrestrial locomotion suggests that COM heave motion scales with positive allometry, and that fish have relatively low COM oscillations for their body size. PMID:24925455

  12. Avoidance behavior and swimming activity of fish to detect pH changes

    SciTech Connect

    Nakamura, F.

    1986-12-01

    Usually, the initial response of an animal to an environmental perturbation is changing its behavior. With fish, this may hold an alteration in swimming activity or reactions like avoidance or attraction. The usefulness of fish behavior to detect the changes in chemical water quality was recognized more than 70 years ago. Since that time, many laboratory studies have been performed on the behavioral reactions of aquatic organisms to pollutants, including those resulting from pH changes. However, still there is no conclusive evidence that fish behavior offers an adequate tool to detect chemical pollution. In this study, the use of R-value for swimming activity and D/sup 2/-value for avoidance behavior of toxic warning methods to indicate the development of toxic condition is discussed based on experimental data on pH effects.

  13. Avoiding the flow: refuges expand the swimming potential of coral reef fishes

    NASA Astrophysics Data System (ADS)

    Johansen, J. L.; Fulton, C. J.; Bellwood, D. R.

    2007-09-01

    While many coral reef fishes utilise substratum refuges, the direct influence of water flow and swimming ability on such refuging patterns is yet to be established. This study examined the swimming ability and refuging behaviour of a labrid ( Halichoeres margaritaceus) and a pomacentrid ( Pomacentrus chrysurus) that inhabit high flow, wave-swept coral reef flats. Field observations of refuging patterns were combined with experimental evaluations in a flow tank using a replica of a substratum hole frequently used by these species. Under a range of flow speeds commonly found on the reef flat (0-60 cm s-1), flow within the substratum refuge was reduced to speeds of 0-12 cm s-1, representing a 75-100% flow reduction. Swimming ability of each species was then tested at 60 cm s-1 with and without access to this flow refuge. Both species were able to maintain activity within the 60 cm s-1 flow for considerably longer when provided with a refuge, with increases from approximately 39 min to 36 h for H. margaritaceus and 8 min to 88 h for P. chrysurus. Despite H. margaritaceus having the strongest swimming ability without access to a refuge, P. chrysurus was able to maintain swimming activity more than twice as long as H. margaritaceus when provided with a refuge. These increases in activity are probably due to energetic savings, with this type of refuge providing an estimated 95% energy saving over swimming directly into a unidirectional flow of 60 cm s-1. These results highlight the major advantages provided by refuging behaviour and emphasise the importance of habitat refuges in shaping patterns of habitat use in reef fishes.

  14. Swimming Droplets

    NASA Astrophysics Data System (ADS)

    Maass, Corinna C.; Krüger, Carsten; Herminghaus, Stephan; Bahr, Christian

    2016-03-01

    Swimming droplets are artificial microswimmers based on liquid droplets that show self-propelled motion when immersed in a second liquid. These systems are of tremendous interest as experimental models for the study of collective dynamics far from thermal equilibrium. For biological systems, such as bacterial colonies, plankton, or fish swarms, swimming droplets can provide a vital link between simulations and real life. We review the experimental systems and discuss the mechanisms of self-propulsion. Most systems are based on surfactant-stabilized droplets, the surfactant layer of which is modified in a way that leads to a steady Marangoni stress resulting in an autonomous motion of the droplet. The modification of the surfactant layer is caused either by the advection of a chemical reactant or by a solubilization process. Some types of swimming droplets possess a very simple design and long active periods, rendering them promising model systems for future studies of collective behavior.

  15. Fish and robots swimming together: attraction towards the robot demands biomimetic locomotion

    PubMed Central

    Marras, Stefano; Porfiri, Maurizio

    2012-01-01

    The integration of biomimetic robots in a fish school may enable a better understanding of collective behaviour, offering a new experimental method to test group feedback in response to behavioural modulations of its ‘engineered’ member. Here, we analyse a robotic fish and individual golden shiners (Notemigonus crysoleucas) swimming together in a water tunnel at different flow velocities. We determine the positional preference of fish with respect to the robot, and we study the flow structure using a digital particle image velocimetry system. We find that biomimetic locomotion is a determinant of fish preference as fish are more attracted towards the robot when its tail is beating rather than when it is statically immersed in the water as a ‘dummy’. At specific conditions, the fish hold station behind the robot, which may be due to the hydrodynamic advantage obtained by swimming in the robot's wake. This work makes a compelling case for the need of biomimetic locomotion in promoting robot–animal interactions and it strengthens the hypothesis that biomimetic robots can be used to study and modulate collective animal behaviour. PMID:22356819

  16. Fish and robots swimming together: attraction towards the robot demands biomimetic locomotion.

    PubMed

    Marras, Stefano; Porfiri, Maurizio

    2012-08-01

    The integration of biomimetic robots in a fish school may enable a better understanding of collective behaviour, offering a new experimental method to test group feedback in response to behavioural modulations of its 'engineered' member. Here, we analyse a robotic fish and individual golden shiners (Notemigonus crysoleucas) swimming together in a water tunnel at different flow velocities. We determine the positional preference of fish with respect to the robot, and we study the flow structure using a digital particle image velocimetry system. We find that biomimetic locomotion is a determinant of fish preference as fish are more attracted towards the robot when its tail is beating rather than when it is statically immersed in the water as a 'dummy'. At specific conditions, the fish hold station behind the robot, which may be due to the hydrodynamic advantage obtained by swimming in the robot's wake. This work makes a compelling case for the need of biomimetic locomotion in promoting robot-animal interactions and it strengthens the hypothesis that biomimetic robots can be used to study and modulate collective animal behaviour. PMID:22356819

  17. Mechanical design, fabrication, and test of biomimetic fish robot using LIPCA as artificial muscle

    NASA Astrophysics Data System (ADS)

    Wiguna, T.; Syaifuddin, M.; Park, Hoon C.; Heo, S.

    2006-03-01

    This paper presents a mechanical design, fabrication and test of biomimetic fish robot using the Lightweight Piezocomposite Curved Actuator (LIPCA). We have designed a mechanism for converting actuation of the LIPCA into caudal fin movement. This linkage mechanism consists of rack-pinion system and four-bar linkage. We also have tested four types of caudal fin in order to examine effect of different shape of caudal fin on thrust generation by tail beat. Subsequently, based on the caudal fin test, four caudal fins which resemble fish caudal fin shapes of ostraciiform, subcarangiform, carangiform and thunniform, respectively, are attached to the posterior part of the robotic fish. The swimming test using 300 V pp input with 1 Hz to 1.5 Hz frequency was conducted to investigate effect of changing tail beat frequency and shape of caudal fin on the swimming speed of the robotic fish. The maximum swimming speed was reached when the device was operated at its natural swimming frequency. At the natural swimming frequency 1 Hz, maximum swimming speeds of 1.632 cm/s, 1.776 cm/s, 1.612 cm/s and 1.51 cm/s were reached for ostraciiform-, subcarangiform-, carangiform- and thunniform-like caudal fins, respectively. Strouhal numbers, which are a measure of thrust efficiency, were calculated in order to examine thrust performance of the present biomimetic fish robot. We also approximated the net forward force of the robotic fish using momentum conservation principle.

  18. Individual variation in the swimming performance of fishes: An overlooked source of variation in toxicity studies

    SciTech Connect

    Kolok, A.S. ||; Plaisance, E.P.; Abdelghani, A.

    1998-02-01

    A commonly used indicator of sublethal stress in fish is impaired swimming performance. Analysis of performance data usually employs a simple comparison, in which the mean of a stressed group of fish is compared to that of a control group. Although such a comparison is satisfactory in many cases, a comparison emphasizing individual variation in performance can yield valuable information unattainable by a means comparison. In this experiment, the authors determined critical swimming speeds of subadult male fathead minnows before and after exposure to contaminated sediments from Devil`s Swamp, Louisiana, USA. The data were then analyzed using a means comparison and an individual approach to illustrate the differences in explanatory power between the two approaches.

  19. Thunniform swimming: muscle dynamics and mechanical power production of aerobic fibres in yellowfin tuna (Thunnus albacares).

    PubMed

    Shadwick, Robert E; Syme, Douglas A

    2008-05-01

    We studied the mechanical properties of deep red aerobic muscle of yellowfin tuna (Thunnus albacares), using both in vivo and in vitro methods. In fish swimming in a water tunnel at 1-3 L s(-1) (where L is fork length), muscle length changes were recorded by sonomicrometry, and activation timing was quantified by electromyography. In some fish a tendon buckle was also implanted on the caudal tendon to measure instantaneous muscle forces transmitted to the tail. Between measurement sites at 0.45 to 0.65 L, the wave of muscle shortening progressed along the body at a relatively high velocity of 1.7 L per tail beat period, and a significant phase shift (31+/-4 degrees ) occurred between muscle shortening and local midline curvature, both suggesting red muscle power is directed posteriorly, rather than causing local body bending, which is a hallmark of thunniform swimming. Muscle activation at 0.53 L was initiated at about 50 degrees of the tail beat period and ceased at about 160 degrees , where 90 degrees is peak muscle length and 180 degrees is minimum length. Strain amplitude in the deep red fibres at 0.5 L was +/-5.4%, double that predicted from midline curvature analysis. Work and power production were measured in isolated bundles of red fibres from 0.5 L by the work loop technique. Power was maximal at 3-4 Hz and fell to less than 50% of maximum after 6 Hz. Based on the timing of activation, muscle strain, tail beat frequencies and forces in the caudal tendon while swimming, we conclude that yellowfin tuna, like skipjack, use their red muscles under conditions that produce near-maximal power output while swimming. Interestingly, the red muscles of yellowfin tuna are slower than those of skipjack, which corresponds with the slower tail beat frequencies and cruising speeds in yellowfin. PMID:18456888

  20. Swimming behaviour of fish under diminished gravity conditions - a review

    NASA Astrophysics Data System (ADS)

    Anken, Ralf; Hilbig, Reinhard; Anken, Ralf

    In vertebrates (including humans) altered gravitational environments (∆g) such as weightlessness (microgravity, µg) can induce malfunctions of the inner ears leading to severe sensorymotor disorders (intersensory-conflict-theory) including space motion sickness (SMS), a kinetosis. SMS is an important operational problem, since the sensorimotor performance of an affected astronaut is severely impaired especially in the first two to three days of a space mission. Of course human subjects are not amenable to invasive research techniques for studying the basis of SMS and related kinetoses. Other vertebrates such as fish are therefore used as model systems since their peripheral and central vestibular system - at least at the level of primary vestibular brain nuclei - is largely homologous to that of humans. Moreover, fish are capable to maintain spatial orientation and postural control in 3 dimensions even in dark or turbid waters, because they are particularly sensitive to ∆g. The observations made, using fish as a model system, to contribute to the understanding of human kinetosis susceptibility will be reviewed. A conclusion will address lessions learned. Acknowledgement: Numerous of the studies to be reviewed were financially supported by the German Aerospace Center (DLR) (FKZ: 50 WB 9997/50 WB 0527).

  1. Mechanical and scaling considerations for efficient jellyfish swimming

    NASA Astrophysics Data System (ADS)

    Hoover, Alexander; Miller, Laura; Griffith, Boyce

    2015-11-01

    With a fossil record dating over half a billion years, jellyfish represent one of the earliest examples of how multicellular organisms first organized into moving systems. Lacking an agonist-antagonist muscle pairing, jellyfish swim via a process of elastic deformation and recoil. Jellyfish propulsion is generated via the coordinated contraction of its elastic bell by its coronal swimming muscles and a complementary re-expansion that is passively driven by stored elastic energy. Recent studies have found jellyfish to be one of the most efficient swimmers due to its low energy expenditure in their forward movement. Using an immersed boundary framework, we will further examine the efficiency of jellyfish swimming by incorporating material models that are informed by the musculature present in jellyfish into a model of the elastic jellyfish bell in three dimensions. The fully-coupled fluid structure interaction problem is solved using an adaptive and parallelized version of the immersed boundary method (IBAMR). This model is then used to explore how variability in the mechanical properties of the bell affect the work done by the bell as well as the cost of transport related to jellyfish locomotion. We then examine how the efficiency of this system is affected by the Reynolds number.

  2. The effects of caudal fin loss and regeneration on the swimming performance of three cyprinid fish species with different swimming capacities.

    PubMed

    Fu, Cheng; Cao, Zhen-Dong; Fu, Shi-Jian

    2013-08-15

    In nature, the caudal fins of fish species are frequently lost to some extent by aggressive behaviour, predation and diseases. To test whether the swimming performance of fish with different swimming capacities would be differentially affected due to caudal fin loss and regeneration, we investigated the critical swimming speed (Ucrit), swimming metabolic rate (M(O2)), tail beat frequency (f(TB)) and tail beat amplitude (A(TB)) after caudal fin loss and regeneration (20 days) in juveniles of three cyprinid fish species: the qingbo (Spinibarbus sinensis; strong swimmer), the common carp (Cyprinus carpio; intermediate swimmer) and the goldfish (Carassius auratus; poor swimmer). The Ucrit values of the caudal-fin-lost qingbo, common carp and goldfish were 49, 32 and 35% significantly lower than those of the control groups, respectively. The maximum tail beat amplitude (A(TBmax)) (all three fishes), the maximum tail beat frequency (f(TBmax)) (only the common carp and the goldfish) and/or the active metabolic rate (M(O2active)) (only the common carp) of the caudal-fin-lost fish were significantly higher than those of the control groups. After 20 days of recovery, the caudal fins recovered to 41, 47 and 24% of those of the control groups for the qingbo, the common carp and the goldfish, respectively. However, the Ucrit values of the fin-regenerated qingbo, common carp and goldfish recovered to 86, 91 and 95% of those of the control group, respectively. The caudal-fin-regenerated qingbo and common carp showed a significantly higher A(TBmax) and f(TBmax), respectively, compared with those of the control groups. The qingbo had a higher f(TBmax) but a lower A(TBmax) than the common carp and the goldfish, which suggested that a strong swimmer may maintain swimming speed primarily by maintaining a greater f(TBmax), for which the caudal fin plays a more important role during swimming, than a poor swimmer. The M(O2active) of fish (common carp) with a redundant respiratory

  3. Neural mechanism of optimal limb coordination in crustacean swimming.

    PubMed

    Zhang, Calvin; Guy, Robert D; Mulloney, Brian; Zhang, Qinghai; Lewis, Timothy J

    2014-09-23

    A fundamental challenge in neuroscience is to understand how biologically salient motor behaviors emerge from properties of the underlying neural circuits. Crayfish, krill, prawns, lobsters, and other long-tailed crustaceans swim by rhythmically moving limbs called swimmerets. Over the entire biological range of animal size and paddling frequency, movements of adjacent swimmerets maintain an approximate quarter-period phase difference with the more posterior limbs leading the cycle. We use a computational fluid dynamics model to show that this frequency-invariant stroke pattern is the most effective and mechanically efficient paddling rhythm across the full range of biologically relevant Reynolds numbers in crustacean swimming. We then show that the organization of the neural circuit underlying swimmeret coordination provides a robust mechanism for generating this stroke pattern. Specifically, the wave-like limb coordination emerges robustly from a combination of the half-center structure of the local central pattern generating circuits (CPGs) that drive the movements of each limb, the asymmetric network topology of the connections between local CPGs, and the phase response properties of the local CPGs, which we measure experimentally. Thus, the crustacean swimmeret system serves as a concrete example in which the architecture of a neural circuit leads to optimal behavior in a robust manner. Furthermore, we consider all possible connection topologies between local CPGs and show that the natural connectivity pattern generates the biomechanically optimal stroke pattern most robustly. Given the high metabolic cost of crustacean swimming, our results suggest that natural selection has pushed the swimmeret neural circuit toward a connection topology that produces optimal behavior. PMID:25201976

  4. Size and Cell Number of the Utricle in kinetotically swimming Fish: A parabolic Aircraft Flight Study

    NASA Astrophysics Data System (ADS)

    Baeuerle, A.; Anken, R.; Baumhauer, N.; Hilbig, R.; Rahmann, H.

    Humans taking part in parabolic aircraft flights (PAFs) may suffer from space motion sickness (SMS, a kinetosis). Since it has been repeatedly shown earlier that some fish of a given batch also reveal a kinetotic behaviour during PAFs (especially so-called spinning movements and looping responses), and due to the homology of the vestibular apparatus among all vertebrates, fish can be used as model systems to investigate the origin of susceptibility to motion sickness. Therefore, we examined the utricular maculae (they are responsible for the internalisation of gravity in teleosteans) of fish swimming kinetotically during the μg-phases in the course of PAFs in comparison with animals from the same batch who swam normally. On the light microscopical level, it was found that the total number of both sensory and supporting cells of the utricular maculae did not differ between kinetotic animals as compared to normally swimming fish. Cell density (sensory and supporting cells/100μm -μm), however, was reduced in kinetotic animals (p<0.0001), which seemed to be due to malformed epithelial cells (increase in cell size) of the kinetotic specimens. Susceptibility to kinetoses may therefore originate in asymmetric inner ear otoliths as has been suggested earlier, but also in genetically predispositioned, malformed sensory epithelia. This work was financially supported by the German Aerospace Center (DLR) e.V. (FKZ: 50 WB 9997).

  5. Size and cell number of the utricle in kinetotically swimming fish: a parabolic aircraft flight study

    NASA Astrophysics Data System (ADS)

    Bäuerle, A.; Anken, R. H.; Hilbig, R.; Baumhauer, N.; Rahmann, H.

    2004-01-01

    Humans taking part in parabolic aircraft flights (PAFs) may suffer from space motion sickness (SMS, a kinetosis). Since it has been repeatedly shown earlier that some fish of a given batch also reveal a kinetotic behavior during PAFs (especially so-called spinning movements and looping responses) and due to the homology of the vestibular apparatus among all vertebrates, fish can be used as model systems to investigate the origin of susceptibility to motion sickness. Therefore, we examined the utricular maculae (they are responsible for the internalization of gravity in teleosteans) of fish swimming kinetotically at microgravity in comparison with animals from the same batch who swam normally. On the histological level, it was found that the total number of both sensory and supporting cells of the utricular maculae did not differ between kinetotic animals as compared to normally swimming fish. Cell density (sensory and supporting cells/100 μm 2), however, was reduced in kinetotic animals ( p < 0.0001), which seemed to be due to malformed epithelial cells (increase in cell size) of the kinetotic specimens. Susceptibility to kinetoses may therefore originate in malformed sensory epithelia.

  6. Size and cell number of the utricle in kinetotically swimming fish: a parabolic aircraft flight study.

    PubMed

    Baüerle, A; Anken, R H; Hilbig, R; Baumhauer, N; Rahmann, H

    2004-01-01

    Humans taking part in parabolic aircraft flights (PAFs) may suffer from space motion sickness (SMS, a kinetosis). Since it has been repeatedly shown earlier that some fish of a given batch also reveal a kinetotic behavior during PAFs (especially so-called spinning movements and looping responses) and due to the homology of the vestibular apparatus among all vertebrates, fish can be used as model systems to investigate the origin of susceptibility to motion sickness. Therefore, we examined the utricular maculae (they are responsible for the internalization of gravity in teleosteans) of fish swimming kinetotically at microgravity in comparison with animals from the same batch who swam normally. On the histological level, it was found that the total number of both sensory and supporting cells of the utricular maculae did not differ between kinetotic animals as compared to normally swimming fish. Cell density (sensory and supporting cells/100 micrometers2), however, was reduced in kinetotic animals (p<0.0001), which seemed to be due to malformed epithelial cells (increase in cell size) of the kinetotic specimens. Susceptibility to kinetoses may therefore originate in malformed sensory epithelia. PMID:15880898

  7. Statistics of the electrosensory input in the freely swimming weakly electric fish Apteronotus leptorhynchus.

    PubMed

    Fotowat, Haleh; Harrison, Reid R; Krahe, Rüdiger

    2013-08-21

    The neural computations underlying sensory-guided behaviors can best be understood in view of the sensory stimuli to be processed under natural conditions. This input is often actively shaped by the movements of the animal and its sensory receptors. Little is known about natural sensory scene statistics taking into account the concomitant movement of sensory receptors in freely moving animals. South American weakly electric fish use a self-generated quasi-sinusoidal electric field for electrolocation and electrocommunication. Thousands of cutaneous electroreceptors detect changes in the transdermal potential (TDP) as the fish interact with conspecifics and the environment. Despite substantial knowledge about the circuitry and physiology of the electrosensory system, the statistical properties of the electrosensory input evoked by natural swimming movements have never been measured directly. Using underwater wireless telemetry, we recorded the TDP of Apteronotus leptorhynchus as they swam freely by themselves and during interaction with a conspecific. Swimming movements caused low-frequency TDP amplitude modulations (AMs). Interacting with a conspecific caused additional AMs around the difference frequency of their electric fields, with the amplitude of the AMs (envelope) varying at low frequencies due to mutual movements. Both AMs and envelopes showed a power-law relationship with frequency, indicating spectral scale invariance. Combining a computational model of the electric field with video tracking of movements, we show that specific swimming patterns cause characteristic spatiotemporal sensory input correlations that contain information that may be used by the brain to guide behavior. PMID:23966697

  8. Vortex dynamics in the wake of a mechanical fish

    NASA Astrophysics Data System (ADS)

    Brücker, Christoph; Bleckmann, Horst

    This study focuses on the three-dimensional flow around a mechanical fish model, which reproduces the typical undulatory body and fin motion of a carangiform swimmer. The mechanical model consists of a flexible skeleton embedded in a soft transparent silicone body, which is connected with two cams to a flapping and bending hinge generating a traveling wave motion with increasing amplitude from anterior to posterior, extending to a combined heaving and pitching motion at the fin. The model is submerged in a water tank and towed at the characteristic swimming speed for the neutral swimming mode at U/V = 1. The method of Scanning Particle Image Velocimetry was used to analyze the three-dimensional time-dependent flow field in the axial and saggital planes. The results confirm the earlier observations that the wake develops into a chain of vortex rings which travel sidewards perpendicular to the swimming direction. However, instead of one single vortex shed at each tail beat half-cycle we observed a pair of two vortex rings being shed. Each pair consists of a larger main vortex ring corresponding to the tail beat start-stop vortex, while the second vortex ring is due to the body bending motion. The existence of the second vortex reflects the role of the body in undulatory swimming. A simplified model of the fish body comparing it to a plate with a hinged flap demonstrates the link between the sequence of kinematics and vortex shedding.

  9. Vortex dynamics in the wake of a mechanical fish

    NASA Astrophysics Data System (ADS)

    Brücker, Christoph; Bleckmann, Horst

    2007-11-01

    This study focuses on the three-dimensional flow around a mechanical fish model, which reproduces the typical undulatory body and fin motion of a carangiform swimmer. The mechanical model consists of a flexible skeleton embedded in a soft transparent silicone body, which is connected with two cams to a flapping and bending hinge generating a traveling wave motion with increasing amplitude from anterior to posterior, extending to a combined heaving and pitching motion at the fin. The model is submerged in a water tank and towed at the characteristic swimming speed for the neutral swimming mode at U/V = 1. The method of Scanning Particle Image Velocimetry was used to analyze the three-dimensional time-dependent flow field in the axial and saggital planes. The results confirm the earlier observations that the wake develops into a chain of vortex rings which travel sidewards perpendicular to the swimming direction. However, instead of one single vortex shed at each tail beat half-cycle we observed a pair of two vortex rings being shed. Each pair consists of a larger main vortex ring corresponding to the tail beat start stop vortex, while the second vortex ring is due to the body bending motion. The existence of the second vortex reflects the role of the body in undulatory swimming. A simplified model of the fish body comparing it to a plate with a hinged flap demonstrates the link between the sequence of kinematics and vortex shedding.

  10. Lateral Line Layout Correlates with the Differential Hydrodynamic Pressure on Swimming Fish

    NASA Astrophysics Data System (ADS)

    Ristroph, Leif; Liao, James C.; Zhang, Jun

    2015-01-01

    The lateral line of fish includes the canal subsystem that detects hydrodynamic pressure gradients and is thought to be important in swimming behaviors such as rheotaxis and prey tracking. Here, we explore the hypothesis that this sensory system is concentrated at locations where changes in pressure are greatest during motion through water. Using high-fidelity models of rainbow trout, we mimic the flows encountered during swimming while measuring pressure with fine spatial and temporal resolution. The variations in pressure for perturbations in body orientation and for disturbances to the incoming stream are seen to correlate with the sensory network. These findings support a view of the lateral line as a "hydrodynamic antenna" that is configured to retrieve flow signals and also suggest a physical explanation for the nearly universal sensory layout across diverse species.

  11. Effects of prolonged weightlessness on the swimming pattern of fish aboard Skylab 3

    NASA Technical Reports Server (NTRS)

    Von Baumgarten, R. J.; Simmonds, R. C.; Boyd, J. F.; Garriott, O. K.

    1975-01-01

    Looping behavior of minnows aboard Skylab 3 is analyzed. Extensive looping patterns were observed at first look on the third day of weightlessness; thereafter, the frequency of the looping episodes diminished until complete adaptation on the twenty-first day, at which time the fish oriented themselves with their backs to the light. The swimming anomaly could be due to (1) absence of continuous bending of sense hairs to a certain extent by gravity, causing the fish to tilt forward in an attempt to increase leverage on the hairs - in the absence of all gravity, tilting is continued into looping (this hypothesis is supported by parabolic flight experiments with partial gravity, in which only tilting was seen); or (2) an attempt by the fish to create a gravitoinertial stimulus by 'centrifuging' its otoliths by looping.

  12. Automatically Detect and Track Multiple Fish Swimming in Shallow Water with Frequent Occlusion

    PubMed Central

    Qian, Zhi-Ming; Cheng, Xi En; Chen, Yan Qiu

    2014-01-01

    Due to its universality, swarm behavior in nature attracts much attention of scientists from many fields. Fish schools are examples of biological communities that demonstrate swarm behavior. The detection and tracking of fish in a school are of important significance for the quantitative research on swarm behavior. However, different from other biological communities, there are three problems in the detection and tracking of fish school, that is, variable appearances, complex motion and frequent occlusion. To solve these problems, we propose an effective method of fish detection and tracking. In this method, first, the fish head region is positioned through extremum detection and ellipse fitting; second, The Kalman filtering and feature matching are used to track the target in complex motion; finally, according to the feature information obtained by the detection and tracking, the tracking problems caused by frequent occlusion are processed through trajectory linking. We apply this method to track swimming fish school of different densities. The experimental results show that the proposed method is both accurate and reliable. PMID:25207811

  13. Scaling in Free-Swimming Fish and Implications for Measuring Size-at-Time in the Wild

    PubMed Central

    Broell, Franziska; Taggart, Christopher T.

    2015-01-01

    This study was motivated by the need to measure size-at-age, and thus growth rate, in fish in the wild. We postulated that this could be achieved using accelerometer tags based first on early isometric scaling models that hypothesize that similar animals should move at the same speed with a stroke frequency that scales with length-1, and second on observations that the speed of primarily air-breathing free-swimming animals, presumably swimming ‘efficiently’, is independent of size, confirming that stroke frequency scales as length-1. However, such scaling relations between size and swimming parameters for fish remain mostly theoretical. Based on free-swimming saithe and sturgeon tagged with accelerometers, we introduce a species-specific scaling relationship between dominant tail beat frequency (TBF) and fork length. Dominant TBF was proportional to length-1 (r2 = 0.73, n = 40), and estimated swimming speed within species was independent of length. Similar scaling relations accrued in relation to body mass-0.29. We demonstrate that the dominant TBF can be used to estimate size-at-time and that accelerometer tags with onboard processing may be able to provide size-at-time estimates among free-swimming fish and thus the estimation of growth rate (change in size-at-time) in the wild. PMID:26673777

  14. Scaling in Free-Swimming Fish and Implications for Measuring Size-at-Time in the Wild.

    PubMed

    Broell, Franziska; Taggart, Christopher T

    2015-01-01

    This study was motivated by the need to measure size-at-age, and thus growth rate, in fish in the wild. We postulated that this could be achieved using accelerometer tags based first on early isometric scaling models that hypothesize that similar animals should move at the same speed with a stroke frequency that scales with length-1, and second on observations that the speed of primarily air-breathing free-swimming animals, presumably swimming 'efficiently', is independent of size, confirming that stroke frequency scales as length-1. However, such scaling relations between size and swimming parameters for fish remain mostly theoretical. Based on free-swimming saithe and sturgeon tagged with accelerometers, we introduce a species-specific scaling relationship between dominant tail beat frequency (TBF) and fork length. Dominant TBF was proportional to length-1 (r2 = 0.73, n = 40), and estimated swimming speed within species was independent of length. Similar scaling relations accrued in relation to body mass-0.29. We demonstrate that the dominant TBF can be used to estimate size-at-time and that accelerometer tags with onboard processing may be able to provide size-at-time estimates among free-swimming fish and thus the estimation of growth rate (change in size-at-time) in the wild. PMID:26673777

  15. Long-term Behavioral Tracking of Freely Swimming Weakly Electric Fish

    PubMed Central

    Jun, James J.; Longtin, André; Maler, Leonard

    2014-01-01

    Long-term behavioral tracking can capture and quantify natural animal behaviors, including those occurring infrequently. Behaviors such as exploration and social interactions can be best studied by observing unrestrained, freely behaving animals. Weakly electric fish (WEF) display readily observable exploratory and social behaviors by emitting electric organ discharge (EOD). Here, we describe three effective techniques to synchronously measure the EOD, body position, and posture of a free-swimming WEF for an extended period of time. First, we describe the construction of an experimental tank inside of an isolation chamber designed to block external sources of sensory stimuli such as light, sound, and vibration. The aquarium was partitioned to accommodate four test specimens, and automated gates remotely control the animals' access to the central arena. Second, we describe a precise and reliable real-time EOD timing measurement method from freely swimming WEF. Signal distortions caused by the animal's body movements are corrected by spatial averaging and temporal processing stages. Third, we describe an underwater near-infrared imaging setup to observe unperturbed nocturnal animal behaviors. Infrared light pulses were used to synchronize the timing between the video and the physiological signal over a long recording duration. Our automated tracking software measures the animal's body position and posture reliably in an aquatic scene. In combination, these techniques enable long term observation of spontaneous behavior of freely swimming weakly electric fish in a reliable and precise manner. We believe our method can be similarly applied to the study of other aquatic animals by relating their physiological signals with exploratory or social behaviors. PMID:24637642

  16. Investigation of the swimming mechanics of Schistosoma cercariae and its role in disease transmission

    NASA Astrophysics Data System (ADS)

    Krishnamurthy, Deepak; Bhargava, Arjun; Katsikis, Georgios; Prakash, Manu

    2015-11-01

    Schistosomiasis is a Neglected Tropical Disease responsible for the deaths of an estimated 200,000 people annually. Human infection occurs when the infectious forms of the worm known as cercariae swim through freshwater, detect humans and penetrate the skin. Cercarial swimming is a bottleneck in disease transmission since cercariae have finite energy reserves, hence motivating studies of their swimming mechanics. Here we build on earlier studies which revealed the existence of two swimming modes: the tail-first and head-first modes. Of these the former was shown to display a novel symmetry breaking mechanism enabling locomotion at low Reynolds numbers. Here we propose simple models for the two swimming modes based on a three-link swimmer geometry. Using local slender-body-theory, we calculate the swimming gait for these model swimmers and compare with experiments, both on live cercariae and on scaled-up robotic swimmers. We use data from these experiments and the models to calculate the energy expended while swimming in the two modes. This along with long-time tracking of swimming cercariae in a lab setting allows estimation of the decrease in activity of the swimmer as a function of time which is an important factor in cercarial infectivity. Finally, we consider, through experiments and theoretical models, the effects of gravity since cercariae are negatively buoyant and sink in the water column while not swimming. This sinking affects cercarial spatial distribution which is important from a disease perspective.

  17. Swim therapy reduces mechanical allodynia and thermal hyperalgesia induced by chronic constriction nerve injury in rats

    PubMed Central

    Shen, Jun; Fox, Lyle E.; Cheng, Jianguo

    2013-01-01

    Objective Neuropathic pain is common and often difficult to treat because it generally does not respond well to the currently available pain medications or nerve blocks. Recent studies in both humans and animals have suggested that exercise may induce a transient analgesia and reduce acute pain in normal healthy individuals. We examined whether swim therapy could alleviate neuropathic pain in rats. Design Rats were trained to swim over a two week period in warm water. After the rats were trained, neuropathic pain was induced by constricting the right sciatic nerve and regular swimming was resumed. The sensitivity of each hind paw was monitored using the Hargreaves test and von Frey test to evaluate the withdrawal response thresholds to heat and touch. Results The paw ipsilateral to the nerve ligation expressed pain-like behaviors including thermal hyperalgesia and mechanical allodynia. Regular swim therapy sessions significantly reduced the mechanical allodynia and thermal hyperalgesia. Swim therapy had little effect on the withdrawal thresholds for the contralateral paw. In addition, swim therapy alone did not alter the thermal or mechanical thresholds of normal rats. Conclusions The results suggest that regular exercise, including swim therapy, may be an effective treatment for neuropathic pain caused by nerve injuries. This study, showing that swim therapy reduces neuropathic pain behavior in rats, provides a scientific rationale for clinicians to test the efficacy of exercise in the management of neuropathic pain. It may prove to be a safe and cost-effective therapy in a variety of neuropathic pain states. PMID:23438327

  18. Collective response of zebrafish shoals to a free-swimming robotic fish.

    PubMed

    Butail, Sachit; Bartolini, Tiziana; Porfiri, Maurizio

    2013-01-01

    In this work, we explore the feasibility of regulating the collective behavior of zebrafish with a free-swimming robotic fish. The visual cues elicited by the robot are inspired by salient features of attraction in zebrafish and include enhanced coloration, aspect ratio of a fertile female, and carangiform/subcarangiform locomotion. The robot is autonomously controlled with an online multi-target tracking system and swims in circular trajectories in the presence of groups of zebrafish. We investigate the collective response of zebrafish to changes in robot speed, achieved by varying its tail-beat frequency. Our results show that the speed of the robot is a determinant of group cohesion, quantified through zebrafish nearest-neighbor distance, which increases with the speed of the robot until it reaches [Formula: see text]. We also find that the presence of the robot causes a significant decrease in the group speed, which is not accompanied by an increase in the freezing response of the subjects. Findings of this study are expected to inform the design of experimental protocols that leverage the use of robots to study the zebrafish animal model. PMID:24146825

  19. Three-dimensional numerical simulation of hydrodynamic interactions between pectoral-fin vortices and body undulation in a swimming fish

    NASA Astrophysics Data System (ADS)

    Yu, Cheng-Lun; Ting, Shang-Chieh; Yeh, Meng-Kao; Yang, Jing-Tang

    2011-09-01

    We investigated numerically the hydrodynamic interactions between pectoral-fin vortices and body undulation in a fish swimming with carangiform locomotion at a Reynolds number of 3.3 × 104; the three-dimensional, viscous, incompressible, Navier-Stokes equations were solved with a finite-volume method. For a fish swimming with the pectoral fins abducted, we characterized the wake flow structures, forces, and power consumption with respect to various Strouhal numbers. The numerical results reveal that a pair of vortices is formed immediately behind the abducted pectoral fins of a swimming fish. There exist hydrodynamic interactions between the pectoral-fin vortices and the undulating fish body. For Strouhal numbers in a range 0.2-0.8, the body undulation impedes the shedding of pectoral-fin vortices, resulting in vortices closely attached to the pectoral fins. In contrast, for Strouhal number = 0.1, the pectoral-fin vortices are shed from the pectoral fins and drift downstream. The low-pressure suction forces arising from the shed pectoral-fin vortices facilitate lateral movements of the fish body, decreasing the power consumption. This phenomenon indicates the possibility for an actual fish to harvest energy from the shed pectoral-fin vortices.

  20. Bottles as models: predicting the effects of varying swimming speed and morphology on size selectivity and filtering efficiency in fishes.

    PubMed

    Paig-Tran, E W Misty; Bizzarro, Joseph J; Strother, James A; Summers, Adam P

    2011-05-15

    We created physical models based on the morphology of ram suspension-feeding fishes to better understand the roles morphology and swimming speed play in particle retention, size selectivity and filtration efficiency during feeding events. We varied the buccal length, flow speed and architecture of the gills slits, including the number, size, orientation and pore size/permeability, in our models. Models were placed in a recirculating flow tank with slightly negatively buoyant plankton-like particles (~20-2000 μm) collected at the simulated esophagus and gill rakers to locate the highest density of particle accumulation. Particles were captured through sieve filtration, direct interception and inertial impaction. Changing the number of gill slits resulted in a change in the filtration mechanism of particles from a bimodal filter, with very small (≤ 50 μm) and very large (>1000 μm) particles collected, to a filter that captured medium-sized particles (101-1000 μm). The number of particles collected on the gill rakers increased with flow speed and skewed the size distribution towards smaller particles (51-500 μm). Small pore sizes (105 and 200 μm mesh size) had the highest filtration efficiencies, presumably because sieve filtration played a significant role. We used our model to make predictions about the filtering capacity and efficiency of neonatal whale sharks. These results suggest that the filtration mechanics of suspension feeding are closely linked to an animal's swimming speed and the structural design of the buccal cavity and gill slits. PMID:21525310

  1. Mechanisms of anguilliform locomotion in fishes studied using simple three-dimensional physical models.

    PubMed

    Lim, Jeanette L; Lauder, George V

    2016-01-01

    Physical models enable researchers to systematically examine complex and dynamic mechanisms of underwater locomotion in ways that would be challenging with freely swimming animals. Previous research on undulatory locomotion, for example, has used rectangular flexible panels that are effectively two-dimensional as proxies for the propulsive surfaces of swimming fishes, but these bear little resemblance to the bodies of elongate eel-like swimming animals. In this paper we use a polyurethane rod (round cross-section) and bar (square cross-section) to represent the body of a swimming Pacific hagfish (Eptatretus stoutii). We actuated the rod and bar in both heave and pitch using a mechanical controller to generate a propulsive wave at frequencies between 0.5 and 2.5 Hz. We present data on (1) how kinematic swimming patterns change with driving frequency in these elongate fish-like models, (2) the thrust-generating capability of these simple models, (3) how forces and work done during propulsion compare between cross-sectional shapes, (4) the wake flow patterns in these swimming models using particle image velocimetry. We also contrast kinematic and hydrodynamic patterns produced by bar and rod models to comparable new experimental data on kinematics and wake flow patterns from freely swimming hagfish. Increasing the driving frequency of bar and rod models reduced trailing edge amplitude and wavelength, and above 2 Hz a nodal point appeared in the kinematic wave. Above 1 Hz, both the rod and bar generated net thrust, with the work per cycle reaching a minimum at 1.5 Hz, and the bar always requiring more work per cycle than the rod. Wake flow patterns generated by the swimming rod and bar included clearly visible lateral jets, but not the caudolaterally directed flows seen in the wakes from freely swimming hagfish. PMID:27378052

  2. Mechanics of swimming at the small scale in complex fluids

    NASA Astrophysics Data System (ADS)

    Powers, Thomas

    2015-03-01

    Recent experiments with bacteria in liquid crystalline solutions have revealed that nematic order affects the swimming behavior of bacteria. Motivated by these observations, we study a simple model of low-Reynolds-number swimming in an anisotropic fluid, that of an infinitely long two-dimensional sheet deforming via propagating transverse or longitudinal waves and immersed in a hexatic or a nematic liquid crystal. The liquid crystal is categorized by the dimensionless Ericksen number Er, which compares viscous and elastic effects. Paying special attention to the anchoring strength at the interface of the liquid crystal and the swimmer, we calculate how swimming speed depends on Er for small amplitude waves. We study both the sinusoidal steady-state problem as well as the startup problem in which the swimmer starts from rest.

  3. Spatial Expression of Otolith Matrix Protein-1 and Otolin-1 in Normally and Kinetotically Swimming Fish.

    PubMed

    Weigele, Jochen; Franz-Odendaal, Tamara A; Hilbig, Reinhard

    2015-10-01

    Kinetosis (motion sickness) has been repeatedly shown to affect some fish of a given clutch following the transition from 1g to microgravity or from hypergravity to 1g. This susceptibility to kinetosis may be correlated with irregular inner ear otolith growth. Otoliths are mainly composed of calcium carbonate and matrix proteins, which play an important role in the process of otolith mineralization. Here, we examine the morphology of otoliths and the expression pattern of the major otolith proteins OMP-1 and otolin-1 in a series of hypergravity experiments. In the utricle, OMP-1 is present in centripetal (medial) and centrifugal (lateral) regions of the meshwork area. In the saccule, OMP-1 was expressed within a dorsal and a ventral narrow band of the meshwork area opposite to the periphery of the sulcus acusticus. In normal animals, the spatial expression pattern of OMP-1 reaches more posteriorly in the centrifugal aspect and is considerably broader in the centripetal portion of the utricle compared to kinetotic animals. However, otolin-1 was not expressed in the utricule. In the saccule, no differences were observed for either gene when comparing normal and kinetotically behaving fish. The difference in the utricular OMP-1 expression pattern between normally and kinetotically swimming fish indicates a different otolith morphology and thus a different geometry of the otoliths resting on the corresponding sensory maculae. As the utricle is the endorgan responsible for sensing gravity, the aberrant morphology of the utricular otoliths, based on OMP-1 expression, likely leads to the observed kinetotic behavior. PMID:26096990

  4. Passive mechanical models of fish caudal fins: effects of shape and stiffness on self-propulsion.

    PubMed

    Feilich, Kara L; Lauder, George V

    2015-06-01

    Fishes are found in a great variety of body forms with tail shapes that vary from forked tuna-like tails to the square-shaped tails found in some deep-bodied species. Hydrodynamic theory suggests that a fish's body and tail shape affects undulatory swimming performance. For example, a narrow caudal peduncle is believed to reduce drag, and a tuna-like tail to increase thrust. Despite the prevalence of these assertions, there is no experimental verification of the hydrodynamic mechanisms that may confer advantages on specific forms. Here, we use a mechanically-actuated flapping foil model to study how two aspects of shape, caudal peduncle depth and presence or absence of a forked caudal fin, may affect different aspects of swimming performance. Four different foil shapes were each made of plastics of three different flexural stiffnesses, permitting us to study how shape might interact with stiffness to produce swimming performance. For each foil, we measured the self-propelling swimming speed. In addition, we measured the forces, torques, cost of transport and power coefficient of each foil swimming at its self-propelling speed. There was no single 'optimal' foil exhibiting the highest performance in all metrics, and for almost all measures of swimming performance, foil shape and flexural stiffness interacted in complicated ways. Particle image velocimetry of several foils suggested that stiffness might affect the relative phasing of the body trailing edge and the caudal fin leading edge, changing the flow incident to the tail, and affecting hydrodynamics of the entire foil. The results of this study of a simplified model of fish body and tail morphology suggest that considerable caution should be used when inferring a swimming performance advantage from body and tail shape alone. PMID:25879846

  5. Maximum sustainable speed, energetics and swimming kinematics of a tropical carangid fish, the green jack Caranx caballus.

    PubMed

    Dickson, K A; Donley, J M; Hansen, M W; Peters, J A

    2012-06-01

    Maximum sustained swimming speeds, swimming energetics and swimming kinematics were measured in the green jack Caranx caballus (Teleostei: Carangidae) using a 41 l temperature-controlled, Brett-type swimming-tunnel respirometer. In individual C. caballus [mean ±s.d. of 22·1 ± 2·2 cm fork length (L(F) ), 190 ± 61 g, n = 11] at 27·2 ± 0·7° C, mean critical speed (U(crit)) was 102·5 ± 13·7 cm s⁻¹ or 4·6 ± 0·9 L(F) s⁻¹. The maximum speed that was maintained for a 30 min period while swimming steadily using the slow, oxidative locomotor muscle (U(max,c)) was 99·4 ± 14·4 cm s⁻¹ or 4·5 ± 0·9 L(F) s⁻¹. Oxygen consumption rate (M in mg O₂ min⁻¹) increased with swimming speed and with fish mass, but mass-specific M (mg O₂ kg⁻¹ h⁻¹) as a function of relative speed (L(F) s⁻¹) did not vary significantly with fish size. Mean standard metabolic rate (R(S) ) was 170 ± 38 mg O₂ kg⁻¹ h⁻¹, and the mean ratio of M at U(max,c) to R(S) , an estimate of factorial aerobic scope, was 3·6 ± 1·0. The optimal speed (U(opt) ), at which the gross cost of transport was a minimum of 2·14 J kg⁻¹ m⁻¹, was 3·8 L(F) s⁻¹. In a subset of the fish studied (19·7-22·7 cm L(F) , 106-164 g, n = 5), the swimming kinematic variables of tailbeat frequency, yaw and stride length all increased significantly with swimming speed but not fish size, whereas tailbeat amplitude varied significantly with speed, fish mass and L(F) . The mean propulsive wavelength was 86·7 ± 5·6 %L(F) or 73·7 ± 5·2 %L(T) . Mean ±s.d. yaw and tailbeat amplitude values, calculated from lateral displacement of each intervertebral joint during a complete tailbeat cycle in three C. caballus (19·7, 21·6 and 22·7 cm L(F) ; 23·4, 25·3 and 26·4 cm L(T) ), were 4·6 ± 0·1 and 17·1 ± 2·2 %L(T) , respectively. Overall, the sustained swimming performance, energetics, kinematics, lateral displacement and intervertebral bending angles measured in C. caballus

  6. Fluid mechanics of swimming bacteria with multiple flagella

    NASA Astrophysics Data System (ADS)

    Kanehl, Philipp; Ishikawa, Takuji

    2014-04-01

    It is known that some kinds of bacteria swim by forming a bundle of their multiple flagella. However, the details of flagella synchronization as well as the swimming efficiency of such bacteria have not been fully understood. In this study, swimming of multiflagellated bacteria is investigated numerically by the boundary element method. We assume that the cell body is a rigid ellipsoid and the flagella are rigid helices suspended on flexible hooks. Motors apply constant torque to the hooks, rotating the flagella either clockwise or counterclockwise. Rotating all flagella clockwise, bundling of all flagella is observed in every simulated case. It is demonstrated that the counter rotation of the body speeds up the bundling process. During this procedure the flagella synchronize due to hydrodynamic interactions. Moreover, the results illustrated that during running the multiflagellated bacterium shows higher propulsive efficiency (distance traveled per one flagellar rotation) over a bacterium with a single thick helix. With an increasing number of flagella the propulsive efficiency increases, whereas the energetic efficiency decreases, which indicates that efficiency is something multiflagellated bacteria are assigning less priority to than to motility. These findings form a fundamental basis in understanding bacterial physiology and metabolism.

  7. Ichthyophonus-induced cardiac damage: a mechanism for reduced swimming stamina in salmonids

    USGS Publications Warehouse

    Kocan, R.; LaPatra, S.; Gregg, J.; Winton, J.; Hershberger, P.

    2006-01-01

    Swimming stamina, measured as time-to-fatigue, was reduced by approximately two-thirds in rainbow trout experimentally infected with Ichthyophonus. Intensity of Ichthyophonus infection was most severe in cardiac muscle but multiple organs were infected to a lesser extent. The mean heart weight of infected fish was 40% greater than that of uninfected fish, the result of parasite biomass, infiltration of immune cells and fibrotic (granuloma) tissue surrounding the parasite. Diminished swimming stamina is hypothesized to be due to cardiac failure resulting from the combination of parasite-damaged heart muscle and low myocardial oxygen supply during sustained aerobic exercise. Loss of stamina in Ichthyophonus-infected salmonids could explain the poor performance previously reported for wild Chinook and sockeye salmon stocks during their spawning migration. ?? 2006 Blackwell Publishing Ltd.

  8. Measuring abnormal movements in free-swimming fish with accelerometers: implications for quantifying tag and parasite load.

    PubMed

    Broell, Franziska; Burnell, Celene; Taggart, Christopher T

    2016-03-01

    Animal-borne data loggers allow movement, associated behaviours and energy expenditure in fish to be quantified without direct observations. As with any tagging, tags that are attached externally may adversely affect fish behaviour, swimming efficiency and survival. We report on free-swimming wild Atlantic cod (Gadus morhua) held in a large mesocosm that exhibited distinctly aberrant rotational swimming (scouring) when externally tagged with accelerometer data loggers. To quantify the phenomenon, the cod were tagged with two sizes of loggers (18 and 6 g; <2% body mass) that measured tri-axial acceleration at 50 Hz. An automated algorithm, based on body angular rotation, was designed to extract the scouring movements from the acceleration signal (98% accuracy). The algorithm also identified the frequency pattern and associated energy expenditure of scouring in relation to tag load (% body weight). The average per cent time spent scouring (5%) was independent of tag load. The vector of the dynamic body acceleration (VeDBA), used as a proxy for energy expenditure, increased with tag load (r(2)=0.51), and suggests that fish with large tags spent more energy when scouring than fish with small tags. The information allowed us to determine potential detrimental effects of an external tag on fish behaviour and how these effects may be mitigated by tag size. The algorithm can potentially identify similar rotational movements associated with spawning, courtship, feeding and parasite-load shedding in the wild. The results infer a more careful interpretation of data derived from external tags and the careful consideration of tag type, drag, buoyancy and placement, as well as animal buoyancy and species. PMID:26747901

  9. Ontogeny and Sexual Differences in Swimming Proximity to Conspecifics in Response to Visual Cues in Medaka Fish.

    PubMed

    Isoe, Yasuko; Konagaya, Yumi; Yokoi, Saori; Kubo, Takeo; Takeuchi, Hideaki

    2016-06-01

    Adult medaka fish (Oryzias latipes) exhibit complex social behaviors that depend mainly on visual cues from conspecifics. The ontogeny of visually-mediated social behaviors from larval/juvenile to adult medaka fish, however, is unknown. In the present study, we established a simple behavioral paradigm to evaluate the swimming proximity to conspecifics based on visual cues in an inter-individual interaction of two medaka fish throughout life. When two fish were placed separately in a cylindrical tank with a concentric transparent wall, the two fish maintained close proximity to each other. A normal fish inside the tank maintained proximity to an optic nerve-cut fish outside of the tank, while the converse was not true. This behavioral paradigm enabled us to quantify visually-induced motivation of a single fish inside the tank. The proximity was detected from larval/juvenile to adult fish. Larval fish, however, maintained close proximity not only to conspecifics, but also to heterospecifics. As the growth stage increased, the degree of proximity to heterospecifics decreased, suggesting that shoaling preferences toward conspecifics and/or visual ability to recognize conspecifics is refined and established according to the growth stage. Furthermore, the proximity of adult female fish was affected by their reproductive status and social familiarity. Only before spawning, adult females maintained closer proximity to familiar males rather than to unfamiliar males, suggesting that proximity was affected by familiarity in a female-specific manner. This simple behavioral paradigm will contribute to our understanding of the neural basis of the development of visually-mediated social behavior using medaka fish. PMID:27268978

  10. Spiral swimming behavior due to cranial and vertebral lesions associated with Cytophaga psychrophila infections in salmonid fishes

    USGS Publications Warehouse

    Kent, M.L.; Groff, J.M.; Morrison, J.K.; Yasutake, W.T.; Holt, R.A.

    1989-01-01

    C. psychrophila infections of the cranium and anterior vertebrae in salmonid fishes were associated with ataxia, spiral swimming along the axis of the fish, and death. The syndrome was observed in 2-10% of underyearling coho salmon Oncorhynchus kisutch, rainbow troutSalmo gairdneri, and steelhead trout S. gairdneri at several private, state, and federal hatcheries in Washington and Oregon, USA, between 1963 and 1987. Affected fish did not recover and ultimately died. Histological examination consistently revealed subacute to chronic periostitis, osteitis, meningitis, and ganglioneuritis. Inflammation and periosteal proliferation of the anterior vertebrae at the junction of the vertebral column with the cranium with extension into the cranial case was a consistent feature. The adjacent nervous tissue, particularly the medulla, was often compressed by the proliferative lesion, and this may have caused the ataxia. Though bacteria were seldom observed in these lesions. C. psychrophilawas isolated in culture from the cranial cavity of all affected fish that were tested. Epidemiological observations suggested that this bacterium is the causative agent because the spiral swimming behaviour and lesions were observed only in populations that had recovered from acute C. psychrophila infections.

  11. Quantifying Fish Swimming Behavior in Response to Acute Exposure of Aqueous Copper Using Computer Assisted Video and Digital Image Analysis.

    PubMed

    Calfee, Robin D; Puglis, Holly J; Little, Edward E; Brumbaugh, William G; Mebane, Christopher A

    2016-01-01

    Behavioral responses of aquatic organisms to environmental contaminants can be precursors of other effects such as survival, growth, or reproduction. However, these responses may be subtle, and measurement can be challenging. Using juvenile white sturgeon (Acipenser transmontanus) with copper exposures, this paper illustrates techniques used for quantifying behavioral responses using computer assisted video and digital image analysis. In previous studies severe impairments in swimming behavior were observed among early life stage white sturgeon during acute and chronic exposures to copper. Sturgeon behavior was rapidly impaired and to the extent that survival in the field would be jeopardized, as fish would be swept downstream, or readily captured by predators. The objectives of this investigation were to illustrate protocols to quantify swimming activity during a series of acute copper exposures to determine time to effect during early lifestage development, and to understand the significance of these responses relative to survival of these vulnerable early lifestage fish. With mortality being on a time continuum, determining when copper first affects swimming ability helps us to understand the implications for population level effects. The techniques used are readily adaptable to experimental designs with other organisms and stressors. PMID:26967350

  12. Quantifying fish swimming behavior in response to acute exposure of aqueous copper using computer assisted video and digital image analysis

    USGS Publications Warehouse

    Calfee, Robin D.; Puglis, Holly J.; Little, Edward E.; Brumbaugh, William G.; Mebane, Christopher A.

    2016-01-01

    Behavioral responses of aquatic organisms to environmental contaminants can be precursors of other effects such as survival, growth, or reproduction. However, these responses may be subtle, and measurement can be challenging. Using juvenile white sturgeon (Acipenser transmontanus) with copper exposures, this paper illustrates techniques used for quantifying behavioral responses using computer assisted video and digital image analysis. In previous studies severe impairments in swimming behavior were observed among early life stage white sturgeon during acute and chronic exposures to copper. Sturgeon behavior was rapidly impaired and to the extent that survival in the field would be jeopardized, as fish would be swept downstream, or readily captured by predators. The objectives of this investigation were to illustrate protocols to quantify swimming activity during a series of acute copper exposures to determine time to effect during early lifestage development, and to understand the significance of these responses relative to survival of these vulnerable early lifestage fish. With mortality being on a time continuum, determining when copper first affects swimming ability helps us to understand the implications for population level effects. The techniques used are readily adaptable to experimental designs with other organisms and stressors.

  13. Quantifying Fish Swimming Behavior in Response to Acute Exposure of Aqueous Copper Using Computer Assisted Video and Digital Image Analysis

    PubMed Central

    Calfee, Robin D.; Puglis, Holly J.; Little, Edward E.; Brumbaugh, William G.; Mebane, Christopher A.

    2016-01-01

    Behavioral responses of aquatic organisms to environmental contaminants can be precursors of other effects such as survival, growth, or reproduction. However, these responses may be subtle, and measurement can be challenging. Using juvenile white sturgeon (Acipenser transmontanus) with copper exposures, this paper illustrates techniques used for quantifying behavioral responses using computer assisted video and digital image analysis. In previous studies severe impairments in swimming behavior were observed among early life stage white sturgeon during acute and chronic exposures to copper. Sturgeon behavior was rapidly impaired and to the extent that survival in the field would be jeopardized, as fish would be swept downstream, or readily captured by predators. The objectives of this investigation were to illustrate protocols to quantify swimming activity during a series of acute copper exposures to determine time to effect during early lifestage development, and to understand the significance of these responses relative to survival of these vulnerable early lifestage fish. With mortality being on a time continuum, determining when copper first affects swimming ability helps us to understand the implications for population level effects. The techniques used are readily adaptable to experimental designs with other organisms and stressors. PMID:26967350

  14. The Inner Ear and its Coupling to the Swim Bladder in the Deep-Sea Fish Antimora rostrata (Teleostei: Moridae)

    PubMed Central

    Deng, Xiaohong; Wagner, Hans-Joachim; Popper, Arthur N.

    2011-01-01

    The inner ear structure of Antimora rostrata and its coupling to the swim bladder were analyzed and compared with the inner ears of several shallow-water species that also have similar coupling. The inner ear of Antimora has a long saccular otolith and sensory epithelium as compared to many other fishes. Some parts of the membranous labyrinth are thick and rigid, while other parts are thinner but attached tightly to the bony capsule. The partially rigid membranous labyrinth, along with its intimate connection to the swim bladder, may help the inner ear follow the sound oscillations from the swim bladder with better precision than would occur in a less rigid inner ear. In addition, the saccular sensory epithelium has an elaborate structure and an anterior enlargement that may be correlated with increased hearing sensitivity. Some of the features in the inner ear of Antimora may reflect the functional specialization of deep-water living and support the hypothesis that there is enhanced inner ear sensitivity in some deep-sea fishes. PMID:21532967

  15. Mechanisms underlying rhythmic locomotion: body–fluid interaction in undulatory swimming

    PubMed Central

    Chen, J.; Friesen, W. O.; Iwasaki, T.

    2011-01-01

    Swimming of fish and other animals results from interactions of rhythmic body movements with the surrounding fluid. This paper develops a model for the body–fluid interaction in undulatory swimming of leeches, where the body is represented by a chain of rigid links and the hydrodynamic force model is based on resistive and reactive force theories. The drag and added-mass coefficients for the fluid force model were determined from experimental data of kinematic variables during intact swimming, measured through video recording and image processing. Parameter optimizations to minimize errors in simulated model behaviors revealed that the resistive force is dominant, and a simple static function of relative velocity captures the essence of hydrodynamic forces acting on the body. The model thus developed, together with the experimental kinematic data, allows us to investigate temporal and spatial (along the body) distributions of muscle actuation, body curvature, hydrodynamic thrust and drag, muscle power supply and energy dissipation into the fluid. We have found that: (1) thrust is generated continuously along the body with increasing magnitude toward the tail, (2) drag is nearly constant along the body, (3) muscle actuation waves travel two or three times faster than the body curvature waves and (4) energy for swimming is supplied primarily by the mid-body muscles, transmitted through the body in the form of elastic energy, and dissipated into the water near the tail. PMID:21270304

  16. Mechanisms of temperature-dependent swimming: the importance of physics, physiology and body size in determining protist swimming speed.

    PubMed

    Beveridge, Oliver S; Petchey, Owen L; Humphries, Stuart

    2010-12-15

    Body temperatures and thus physiological rates of poikilothermic organisms are determined by environmental temperature. The power an organism has available for swimming is largely dependent on physiological rates and thus body temperature. However, retarding forces such as drag are contingent on the temperature-dependent physical properties of water and on an organism's size. Consequently, the swimming ability of poikilotherms is highly temperature dependent. The importance of the temperature-dependent physical properties of water (e.g. viscosity) in determining swimming speed is poorly understood. Here we propose a semi-mechanistic model to describe how biological rates, size and the physics of the environment contribute to the temperature dependency of microbial swimming speed. Data on the swimming speed and size of a predatory protist and its protist prey were collected and used to test our model. Data were collected by manipulating both the temperature and the viscosity (independently of temperature) of the organism's environment. Protists were either cultured in their test environment (for several generations) or rapidly exposed to their test environment to assess their ability to adapt or acclimate to treatments. Both biological rates and the physics of the environment were predicted to and observed to contribute to the swimming speed of protists. Body size was not temperature dependent, and protists expressed some ability to acclimate to changes in either temperature or viscosity. Overall, using our parameter estimates and novel model, we are able to suggest that 30 to 40% (depending on species) of the response in swimming speed associated with a reduction in temperature from 20 to 5°C is due to viscosity. Because encounter rates between protist predators and their prey are determined by swimming speed, temperature- and viscosity-dependent swimming speeds are likely to result in temperature- and viscosity-dependent trophic interactions. PMID:21113003

  17. Entrainment, retention, and transport of freely swimming fish in junction gaps between commercial barges operating on the Illinois Waterway

    USGS Publications Warehouse

    Davis, Jeremiah J.; Jackson, Patrick; Engel, Frank; LeRoy, Jessica Z.; Neeley, Rebecca N.; Finney, Samuel T.; Murphy, Elizabeth

    2016-01-01

    Large Electric Dispersal Barriers were constructed in the Chicago Sanitary and Ship Canal (CSSC) to prevent the transfer of invasive fish species between the Mississippi River Basin and the Great Lakes Basin while simultaneously allowing the passage of commercial barge traffic. We investigated the potential for entrainment, retention, and transport of freely swimming fish within large gaps (> 50 m3) created at junction points between barges. Modified mark and capture trials were employed to assess fish entrainment, retention, and transport by barge tows. A multi-beam sonar system enabled estimation of fish abundance within barge junction gaps. Barges were also instrumented with acoustic Doppler velocity meters to map the velocity distribution in the water surrounding the barge and in the gap formed at the junction of two barges. Results indicate that the water inside the gap can move upstream with a barge tow at speeds near the barge tow travel speed. Water within 1 m to the side of the barge junction gaps was observed to move upstream with the barge tow. Observed transverse and vertical water velocities suggest pathways by which fish may potentially be entrained into barge junction gaps. Results of mark and capture trials provide direct evidence that small fish can become entrained by barges, retained within junction gaps, and transported over distances of at least 15.5 km. Fish entrained within the barge junction gap were retained in that space as the barge tow transited through locks and the Electric Dispersal Barriers, which would be expected to impede fish movement upstream.

  18. Swimming pool granuloma

    MedlinePlus

    Aquarium granuloma; Fish tank granuloma ... Risks include exposure to swimming pools, salt water aquariums, or ocean fish. ... Wash hands and arms thoroughly after cleaning aquariums. Or, wear rubber gloves when cleaning.

  19. A numerical study of linear and nonlinear kinematic models in fish swimming with the DSD/SST method

    NASA Astrophysics Data System (ADS)

    Tian, Fang-Bao

    2015-03-01

    Flow over two fish (modeled by two flexible plates) in tandem arrangement is investigated by solving the incompressible Navier-Stokes equations numerically with the DSD/SST method to understand the differences between the geometrically linear and nonlinear models. In the simulation, the motions of the plates are reconstructed from a vertically flowing soap film tunnel experiment with linear and nonlinear kinematic models. Based on the simulations, the drag, lift, power consumption, vorticity and pressure fields are discussed in detail. It is found that the linear and nonlinear models are able to reasonably predict the forces and power consumption of a single plate in flow. Moreover, if multiple plates are considered, these two models yield totally different results, which implies that the nonlinear model should be used. The results presented in this work provide a guideline for future studies in fish swimming.

  20. The Physiology and Mechanics of Undulatory Swimming: A Student Laboratory Exercise Using Medicinal Leeches

    ERIC Educational Resources Information Center

    Ellerby, David J.

    2009-01-01

    The medicinal leech is a useful animal model for investigating undulatory swimming in the classroom. Unlike many swimming organisms, its swimming performance can be quantified without specialized equipment. A large blood meal alters swimming behavior in a way that can be used to generate a discussion of the hydrodynamics of swimming, muscle…

  1. Swimming performance of upstream migrant fishes in open-channel flow: A new approach to predicting passage through velocity barriers

    USGS Publications Warehouse

    Haro, A.; Castro-Santos, T.; Noreika, J.; Odeh, M.

    2004-01-01

    The ability to traverse barriers of high-velocity flow limits the distributions of many diadromous and other migratory fish species, yet very few data exist that quantify this ability. We provide a detailed analysis of sprint swimming ability of six migratory fish species (American shad (Alosa sapidissima), alewife (Alosa pseudoharengus), blueback herring (Alosa aestivalis), striped bass (Morone saxatilis), walleye (Stizostedion vitreum), and white sucker (Catostomus commersoni)) against controlled water velocities of 1.5-4.5 m??s-1 in a large, open-channel flume. Performance was strictly voluntary: no coercive incentives were used to motivate fish to sprint. We used these data to generate models of maximum distance traversed, taking into account effects of flow velocity, body length, and temperature. Although the maximum distance traversed decreased with increasing velocity, the magnitude of this effect varied among species. Other covariate effects were likewise variable, with divergent effects of temperature and nonuniform length effects. These effects do not account for all of the variability in performance, however, and behavioral traits may account for observed interspecific differences. We propose the models be used to develop criteria for fish passage structures, culverts, and breached dams.

  2. Influence of long-term altered gravity on the swimming performance of developing cichlid fish: including results from the 2nd German Spacelab Mission D-2

    NASA Astrophysics Data System (ADS)

    Rahmann, H.; Hilbig, R.; Flemming, J.; Slenzka, K.

    This study presents qualitative and quantitative data concerning gravity-dependent changes in the swimming behaviour of developing cichlid fish larvae (Oreochromis mossambicus) after a 9 resp. 10 days exposure to increased acceleration (centrifuge experiments), to reduced gravity (fast-rotating clinostat), changed accelerations (parabolic air craft flights) and to near weightlessness (2nd German Spacelab Mission D-2). Changes of gravity initially cause disturbances of the swimming performance of the fish larvae. With prolonged stay in orbit a step by step normalisation of the swimming behaviour took place in the fish. After return to 1g earth conditions no somersaulting or looping could be detected concerning the fish, but still slow and disorientated movements as compared to controls occurred. The fish larvae adapted to earth gravity within 3-5 days. Fish seem to be in a distinct early developmental stages extreme sensitive and adaptable to altered gravity. However, elder fish either do not react or show compensatory behaviour e.g. escape reactions.

  3. Effects of thermal increase on aerobic capacity and swim performance in a tropical inland fish.

    PubMed

    McDonnell, Laura H; Chapman, Lauren J

    2016-09-01

    Rising water temperature associated with climate change is increasingly recognized as a potential stressor for aquatic organisms, particularly for tropical ectotherms that are predicted to have narrow thermal windows relative to temperate ectotherms. We used intermittent flow resting and swimming respirometry to test for effects of temperature increase on aerobic capacity and swim performance in the widespread African cichlid Pseudocrenilabrus multicolor victoriae, acclimated for a week to a range of temperatures (2°C increments) between 24 and 34°C. Standard metabolic rate (SMR) increased between 24 and 32°C, but fell sharply at 34°C, suggesting either an acclimatory reorganization of metabolism or metabolic rate depression. Maximum metabolic rate (MMR) was elevated at 28 and 30°C relative to 24°C. Aerobic scope (AS) increased between 24 and 28°C, then declined to a level comparable to 24°C, but increased dramatically 34°C, the latter driven by the drop in SMR in the warmest treatment. Critical swim speed (Ucrit) was highest at intermediate temperature treatments, and was positively related to AS between 24 and 32°C; however, at 34°C, the increase in AS did not correspond to an increase in Ucrit, suggesting a performance cost at the highest temperature. PMID:27215345

  4. Mechanics of swimming of multi-body bacterial swarmers using non-labeled cell tracking algorithm

    NASA Astrophysics Data System (ADS)

    Phuyal, Kiran; Kim, Min Jun

    2013-01-01

    To better understand the survival strategy of bacterial swarmers and the mechanical advantages offered by the linear chain (head-tail) attachment of the multiple bacterial bodies in an individual swarmer cell at low Reynolds number, a non-labeled cell tracking algorithm was used to quantify the mechanics of multi-body flagellated bacteria, Serratia marcescens, swimming in a motility buffer that originally exhibited the swarming motility. Swarming is a type of bacterial motility that is characterized by the collective coordinated motion of differentiated swarmer cells on a two-dimensional surface such as agar. In this study, the bacterial swarmers with multiple cell bodies (2, 3, and 4) were extracted from the swarm plate, and then tracked individually after resuspending in the motility medium. Their motion was investigated and compared with individual undifferentiated swimming bacterial cells. The swarmers when released into the motility buffer swam actively without tumbles. Their speeds, orientations, and the diffusive properties were studied by tracking the individual cell trajectories over a short distance in two-dimensional field when the cells are swimming at a constant depth in a bulk aqueous environment. At short time scales, the ballistic trajectory was dominant for both multi-body swarmers and undifferentiated cells.

  5. Novel Pseudotaxis Mechanisms Improve Migration of Straight-Swimming Bacterial Mutants Through a Porous Environment

    PubMed Central

    Mohari, Bitan; Licata, Nicholas A.; Kysela, David T.; Merritt, Peter M.; Mukhopadhay, Suchetana; Brun, Yves V.; Setayeshgar, Sima

    2015-01-01

    ABSTRACT Bacterial locomotion driven by flagella is given directionality by the chemotaxis signal transduction network. In the classic plate assays of migration in porous motility agar, efficient motility is compromised in chemotaxis mutants of diverse bacteria. Nonchemotactic mutants become trapped within the agar matrix. Suppressor mutations that prevent this entanglement but do not restore chemotaxis, a phenomenon designated pseudotaxis, were first reported to arise for Escherichia coli. In this study, novel mechanisms of pseudotaxis have been identified for the plant-pathogenic alphaproteobacterium Agrobacterium tumefaciens. Mutants with chemotaxis mutation suppressor (cms) mutations that impart enhanced migration in motility agar compared to that of their straight-swimming, nonchemotactic parent were isolated. We find that pseudotaxis in A. tumefaciens occurs most commonly via mutations in the D1 domain of the flagellar hook protein, FlgE, but it can also be found less frequently to be due to mutations in the hook length regulator, FliK, or in the motor protein, MotA. Single-cell-tracking studies of cms mutants in bulk medium clearly reveal frequent changes in the direction of swimming, similar to the swimming of strains that are proficient for chemotaxis, but independent of a sensory mechanism. Our results suggest that the tumbling process can be tuned through mutation and evolution to optimize migration through complex, porous environments. PMID:25714707

  6. A Mechanical Fish to Emulate the Fast-Start Performance of Pike

    NASA Astrophysics Data System (ADS)

    Feng, Chengcheng; Modarres-Sadeghi, Yahya

    2010-11-01

    A northern pike is capable of achieving an instantaneous acceleration of 25g, far greater than that achieved by any manmade vehicle. In order to understand the secrets behind achieving such high accelerations, we have built a mechanical fish to emulate the motion of a pike, a fast-start specialist. A live pike bends its body into a C-shaped curve and then uncoils it very quickly to send a traveling wave along its body in order to achieve high acceleration. We have designed a mechanical fish whose motion is accurately controlled by servo motors, to emulate the fast-start by bending its body to a C-shape from its original straight position, and then back to its straight position. An earlier design of a mechanical fish, which could start from an initial C-shaped curve, shed two vortex rings downstream, resulting in a transfer of energy from the fish to water, and therefore, a reaction force from the fluid to the fish. A maximum acceleration of around 4g was achieved in that design. Our new design adds an additional motion to the sequence by first bending the fish from its straight position into a C-shaped curve. Furthermore, this new mechanical fish is designed to be adjustable in swimming pattern, tail shape, tail rigidity, and body rigidity, making it possible to study the influence of all of these parameters on the fast-start performance.

  7. Accommodating the cost of growth and swimming in fish-the applicability of exercise-induced growth to juvenile hapuku (Polyprion oxygeneios).

    PubMed

    Khan, Javed R; Trembath, Caroline; Pether, Steve; Bruce, Michael; Walker, Seumas P; Herbert, Neill A

    2014-01-01

    Induced-swimming can improve the growth and feed conversion efficiency of finfish aquaculture species, such as salmonids and Seriola sp., but some species, such as Atlantic cod, show no or a negative productivity response to exercise. As a possible explanation for these species-specific differences, a recent hypothesis proposed that the applicability of exercise training, as well as the exercise regime for optimal growth gain (ERopt growth), was dependent upon the size of available aerobic metabolic scope (AMS). This study aimed to test this hypothesis by measuring the growth and swimming metabolism of hapuku, Polyprion oxygeneios, to different exercise regimes and then reconciling the metabolic costs of swimming and specific dynamic action (SDA) against AMS. Two 8-week growth trials were conducted with ERs of 0.0, 0.25, 0.5, 0.75, 1, and 1.5 body lengths per second (BL s(-1)). Fish in the first trial showed a modest 4.8% increase in SGR over static controls in the region 0.5-0.75 BL s(-1) whereas the fish in trial 2 showed no significant effect of ER on growth performance. Reconciling the SDA of hapuku with the metabolic costs of swimming showed that hapuku AMS is sufficient to support growth and swimming at all ERs. The current study therefore suggests that exercise-induced growth is independent of AMS and is driven by other factors. PMID:25520662

  8. Scaling the Thrust Production and Energetics of Inviscid Intermittent Swimming

    NASA Astrophysics Data System (ADS)

    Akoz, Emre; Moored, Keith

    2015-11-01

    Many fish have adopted an intermittent swimming gait sometimes referred as a burst-and-coast behavior. By using this gait, fish have been estimated at reducing their energetic cost of swimming by about 50%. Lighthill proposed that the skin friction drag of an undulating body can be around 400% greater than a rigidly-held coasting body, which may explain the energetic savings of intermittent swimming. Recent studies have confirmed the increase in skin friction drag over an undulating body, however, the increase is on the order of 20-70%. This more modest gain in skin friction drag is not sufficient to lead to the observed energy savings. Motivated by these observations, we investigate the inviscid mechanisms behind intermittent swimming for parameters typical of biology. We see that there is an energy savings at a fixed swimming speed for intermittent swimming as compared to continuous swimming. Then we consider three questions: What is the nature of the inviscid mechanism that leads to the observed energy savings, how do the forces and energetics of intermittent swimming scale with the swimming parameters, and what are the limitations to the benefit? Supported by the Office of Naval Research under Program Director Dr. Bob Brizzola, MURI grant number N00014-14-1-0533.

  9. Modeling of breaststroke swimming

    NASA Astrophysics Data System (ADS)

    Karmanov, S. P.; Chernous'ko, F. L.

    2014-02-01

    A mechanical system that models swimming using a pair of two-chain extremities is considered. The motion of the system under study is similar to swimming of a frog and some other animals, in which lower extremities play the main role. This type of motion is characteristic of competitive breaststroke swimming.

  10. Do swimming fish always grow fast? Investigating the magnitude and physiological basis of exercise-induced growth in juvenile New Zealand yellowtail kingfish, Seriola lalandi.

    PubMed

    Brown, Elliot J; Bruce, Michael; Pether, Steve; Herbert, Neill A

    2011-06-01

    There is a wealth of evidence showing that a moderate level of non-stop exercise improves the growth and feed conversion of many active fishes. A diverse number of active fish are currently being farmed, and an optimal level of exercise may feasibly improve the production efficiency of these species in intensive culture systems. Our experiments have set out to resolve the growth benefits of juvenile New Zealand yellowtail kingfish (Seriola lalandi) enforced to swim in currents at various speeds over two temperatures (14.9 and 21.1 °C). We also probed potential sources of physiological efficiency in an attempt to resolve how growth is enhanced at a time of high energetic expenditure. Results show that long-term exercise yields a 10% increase in growth but this occurs in surprisingly low flows (0.75 BL s⁻¹) and only under favourable environmental temperatures (21.1 °C). Experiments using a swim flume respirometer indicate that exercise training has no effect on metabolic scope or critical swimming speeds but it does improve swimming efficiency (lower gross costs of transport, GCOT). Such efficiency may potentially help reconcile the costs of growth and exercise within the range of available metabolic energy (scope). With growth boosted in surprisingly low flows and elevated water temperatures only, further investigations are required to understand the bioenergetics and partitioning of costs in the New Zealand yellowtail kingfish. PMID:21562771

  11. Not all sharks are "swimming noses": variation in olfactory bulb size in cartilaginous fishes.

    PubMed

    Yopak, Kara E; Lisney, Thomas J; Collin, Shaun P

    2015-03-01

    Olfaction is a universal modality by which all animals sample chemical stimuli from their environment. In cartilaginous fishes, olfaction is critical for various survival tasks including localizing prey, avoiding predators, and chemosensory communication with conspecifics. Little is known, however, about interspecific variation in olfactory capability in these fishes, or whether the relative importance of olfaction in relation to other sensory systems varies with regard to ecological factors, such as habitat and lifestyle. In this study, we have addressed these questions by directly examining interspecific variation in the size of the olfactory bulbs (OB), the region of the brain that receives the primary sensory projections from the olfactory nerve, in 58 species of cartilaginous fishes. Relative OB size was compared among species occupying different ecological niches. Our results show that the OBs maintain a substantial level of allometric independence from the rest of the brain across cartilaginous fishes and that OB size is highly variable among species. These findings are supported by phylogenetic generalized least-squares models, which show that this variability is correlated with ecological niche, particularly habitat. The relatively largest OBs were found in pelagic-coastal/oceanic sharks, especially migratory species such as Carcharodon carcharias and Galeocerdo cuvier. Deep-sea species also possess large OBs, suggesting a greater reliance on olfaction in habitats where vision may be compromised. In contrast, the smallest OBs were found in the majority of reef-associated species, including sharks from the families Carcharhinidae and Hemiscyllidae and dasyatid batoids. These results suggest that there is great variability in the degree to which these fishes rely on olfactory cues. The OBs have been widely used as a neuroanatomical proxy for olfactory capability in vertebrates, and we speculate that differences in olfactory capabilities may be the result of

  12. Evidence of antibiotic resistance in free-swimming, top-level marine predatory fishes.

    PubMed

    Blackburn, Jason K; Mitchell, Mark A; Blackburn, Mary-Claire Holley; Curtis, Andrew; Thompson, Bruce A

    2010-03-01

    Antibiotic resistance in bacteria is a growing problem in both human and veterinary medicine. Several studies documented the presence of resistant bacteria in humans, livestock, and domestic animals; however, limited research is available on the presence of antibiotic drug resistance in wildlife species. A cross-sectional study was conducted to estimate the prevalence of resistant bacteria collected from wild-caught, marine predatory fishes. Seven species of sharks and a single teleost species were opportunistically sampled from six different study sites in coastal Belize, coastal and nearshore waters of Louisiana, the Florida Keys, and Martha's Vineyard, Massachusetts. A total of 134 viable bacteria samples were isolated from the cloacal swabs of predatory fishes. Isolates were characterized by Gram-stain morphology and tested for resistance by using the Kirby-Bauer disc diffusion method. Thirteen drugs (penicillin G, piperacillin, ticarcillin, cefotaxime, ceftazidime, ceftiofur, amikacin, gentamicin, ciprofloxacin, enrofloxacin, doxycycline, chloramphenicol, and sulfamethoxazole) were selected for this study. Prevalence was calculated as the total number of isolates resistant to one or more drugs against the total number of samples in that study area or fish population. Sharks sampled in the Florida Keys exhibited the greatest resistance to a wide selection of drugs. Resistance to at least one drug was found in each of the six study sites and in all of the fish species sampled. Multidrug resistance was also documented in most of the study sites. Interspecific comparisons between redfish, Sciaenops ocellata, and sharks from Louisiana offshore waters (which represent species of the Carcharhinus genus) demonstrated a significantly higher prevalence in redfish, which may be because of the older age of the population. The findings of this study confirmed the presence of antibiotic-resistant bacteria in marine predatory fishes from multiple taxa and multiple geographic

  13. Investigation on 3D t wake flow structures of swimming bionic fish

    NASA Astrophysics Data System (ADS)

    Shen, G.-X.; Tan, G.-K.; Lai, G.-J.

    2012-10-01

    A bionic experimental platform was designed for the purpose of investigating time accurate three-dimensional flow field, using digital particle image velocimetry (DSPIV). The wake behind the flapping trail of a robotic fish model was studied at high spatial resolution. The study was performed in a water channel. A robot fish model was designed and built. The model was fixed onto a rigid support framework using a cable-supporting method, with twelve stretched wires. The entire tail of the model can perform prescribed motions in two degrees of freedom, mainly in carangiform mode, by driving its afterbody and lunate caudal fin respectively. The DSPIV system was set up to operate in a translational manner, measuring velocity field in a series of parallel slices. Phase locked measurements were repeated for a number of runs, allowing reconstruction of phase average flow field. Vortex structures with phase history of the wake were obtained. The study reveals some new and complex three-dimensional flow structures in the wake of the fish, including "reverse hairpin vortex" and "reverse Karman S-H vortex rings", allowing insight into physics of this complex flow.

  14. Real-Time Localization of Moving Dipole Sources for Tracking Multiple Free-Swimming Weakly Electric Fish

    PubMed Central

    Jun, James Jaeyoon; Longtin, André; Maler, Leonard

    2013-01-01

    In order to survive, animals must quickly and accurately locate prey, predators, and conspecifics using the signals they generate. The signal source location can be estimated using multiple detectors and the inverse relationship between the received signal intensity (RSI) and the distance, but difficulty of the source localization increases if there is an additional dependence on the orientation of a signal source. In such cases, the signal source could be approximated as an ideal dipole for simplification. Based on a theoretical model, the RSI can be directly predicted from a known dipole location; but estimating a dipole location from RSIs has no direct analytical solution. Here, we propose an efficient solution to the dipole localization problem by using a lookup table (LUT) to store RSIs predicted by our theoretically derived dipole model at many possible dipole positions and orientations. For a given set of RSIs measured at multiple detectors, our algorithm found a dipole location having the closest matching normalized RSIs from the LUT, and further refined the location at higher resolution. Studying the natural behavior of weakly electric fish (WEF) requires efficiently computing their location and the temporal pattern of their electric signals over extended periods. Our dipole localization method was successfully applied to track single or multiple freely swimming WEF in shallow water in real-time, as each fish could be closely approximated by an ideal current dipole in two dimensions. Our optimized search algorithm found the animal’s positions, orientations, and tail-bending angles quickly and accurately under various conditions, without the need for calibrating individual-specific parameters. Our dipole localization method is directly applicable to studying the role of active sensing during spatial navigation, or social interactions between multiple WEF. Furthermore, our method could be extended to other application areas involving dipole source

  15. Swimming in turbulent flow - profitable or costly ?

    NASA Astrophysics Data System (ADS)

    Enders, E. C.; Roy, A. G.

    2004-05-01

    Fish swimming performance has long been of interest to researchers. Experiments on swimming performance are generally performed under conditions which minimise flow heterogeneity. However, fish live in environments were intense fluctuations of flow velocity and pressure occur. Only recently, studies emerged that consider the effect of turbulence on the swimming performance of fish. Research has shown that fish may benefit from turbulence. For example, rainbow trout swimming behind an obstacle which produced stable vortex shedding, profited from the energy of these vortices. Fish adjusted their swimming patterns to slalom between the vortices which resulted in a reduction in muscle activity suggesting that fish reduced energy expenditure of swimming. Similarly, sockeye salmon exploited recirculation zones during upriver spawning migration to minimise energy expenditure. In contrast to these investigations showing that fish may actually profit from turbulence, several studies suggested that turbulence increases energy expenditure of swimming. Sustained swimming speed of fish decreased with increasing turbulence intensity suggesting an increase in swimming costs. Similarly, Atlantic salmon swimming in turbulent flow have 2- to 4-fold increased energy expenditure in comparison to estimates obtained under minimised flow heterogeneity. We will give an overview of recent studies and of new experimental evidence showing how turbulence affects fish behaviour, energetics and distribution and we discuss the relevant scales at which turbulent flow structures affect fish depending on its size. These results are from special interest not only for fisheries management, habitat restoration and biodiversity conservation but also for conceptualisation and construction of migratory fish pathways.

  16. Powered control mechanisms contributing to dynamically stable swimming in porcupine puffers (Teleostei: Diodon holocanthus)

    NASA Astrophysics Data System (ADS)

    Wiktorowicz, Alexis M.; Lauritzen, Dean V.; Gordon, Malcolm S.

    Balances of multiple varying forces must be the basis for the unusually great dynamic stability of swimming pufferfishes. We used high-speed digital video recordings to study biomechanics and kinematics of rectilinear swimming at different speeds of five porcupine puffers in a water tunnel. We measured critical swimming speeds (Ucrit); fin biomechanics, kinematics, and coordination; recoil movements; and gait changes. Major propulsors were pectoral fins at lower speeds; dorsal, anal, and caudal fins at higher speeds. Precise coordination of fin movements produced small recoil movements at speeds below Ucrit. The unusual body shape probably contributes to unconscious stability control.

  17. Powered control mechanisms contributing to dynamically stable swimming in porcupine puffers (Teleostei: Diodon holocanthus)

    NASA Astrophysics Data System (ADS)

    Wiktorowicz, Alexis M.; Lauritzen, Dean V.; Gordon, Malcolm S.

    2007-11-01

    Balances of multiple varying forces must be the basis for the unusually great dynamic stability of swimming pufferfishes. We used high-speed digital video recordings to study biomechanics and kinematics of rectilinear swimming at different speeds of five porcupine puffers in a water tunnel. We measured critical swimming speeds ( U crit); fin biomechanics, kinematics, and coordination; recoil movements; and gait changes. Major propulsors were pectoral fins at lower speeds; dorsal, anal, and caudal fins at higher speeds. Precise coordination of fin movements produced small recoil movements at speeds below U crit. The unusual body shape probably contributes to unconscious stability control.

  18. An integrative CFD model of lamprey swimming

    NASA Astrophysics Data System (ADS)

    Hsu, Chia-Yu; McMillen, Tyler; Fauci, Lisa

    2008-11-01

    Swimming due to sinusoidal body undulations is observed across the full spectrum of swimming organisms, from microscopic flagella to fish. These undulations are achieved due to internal force-generating mechanisms, which, in the case of lamprey are due to a wave of neural activation from head to tail which gives rise to a wave of muscle activation. These active forces are also mediated by passive structural forces. Here we present recent results on a computational model of a swimming lamprey that couples activation of discrete muscle segments, passive elastic forces, and a surrounding viscous, incompressible fluid. The fluid dynamics is modeled by the Navier-Stokes equations at appropriate Reynolds numbers, where the resulting flow field and vortex shedding may be measured.

  19. Ventral tegmental area cholinergic mechanisms mediate behavioral responses in the forced swim test

    PubMed Central

    Addy, N.A.; Nunes, E.J.; Wickham, R.J.

    2015-01-01

    Recent studies revealed a causal link between ventral tegmental area (VTA) phasic dopamine (DA) activity and pro-depressive and antidepressant-like behavioral responses in rodent models of depression. Cholinergic activity in the VTA has been demonstrated to regulate phasic DA activity, but the role of VTA cholinergic mechanisms in depression-related behavior is unclear. The goal of this study was to determine whether pharmacological manipulation of VTA cholinergic activity altered behavioral responding in the forced swim test (FST) in rats. Here, male Sprague-Dawley rats received systemic or VTA-specific administration of the acetylcholinesterase inhibitor, physostigmine (systemic; 0.06 or 0.125 mg/kg, intra-cranial; 1 or 2 μg/side), the muscarinic acetylcholine receptor (AChR) antagonist scopolamine (2.4 or 24 μg/side), or the nicotinic AChR antagonist mecamylamine (3 or 30 μg/side), prior to the FST test session. In control experiments, locomotor activity was also examined following systemic and intra-cranial administration of cholinergic drugs. Physostigmine administration, either systemically or directly into the VTA, significantly increased immobility time in FST, whereas physostigmine infusion into a dorsal control site did not alter immobility time. In contrast, VTA infusion of either scopolamine or mecamylamine decreased immobility time, consistent with an antidepressant-like effect. Finally, the VTA physostigmine-induced increase in immobility was blocked by co-administration with scopolamine, but unaltered by co-administration with mecamylamine. These data show that enhancing VTA cholinergic tone and blocking VTA AChRs has opposing effects in FST. Together, the findings provide evidence for a role of VTA cholinergic mechanisms in behavioral responses in FST. PMID:25865152

  20. Ventral tegmental area cholinergic mechanisms mediate behavioral responses in the forced swim test.

    PubMed

    Addy, N A; Nunes, E J; Wickham, R J

    2015-07-15

    Recent studies revealed a causal link between ventral tegmental area (VTA) phasic dopamine (DA) activity and pro-depressive and antidepressant-like behavioral responses in rodent models of depression. Cholinergic activity in the VTA has been demonstrated to regulate phasic DA activity, but the role of VTA cholinergic mechanisms in depression-related behavior is unclear. The goal of this study was to determine whether pharmacological manipulation of VTA cholinergic activity altered behavioral responding in the forced swim test (FST) in rats. Here, male Sprague-Dawley rats received systemic or VTA-specific administration of the acetylcholinesterase inhibitor, physostigmine (systemic; 0.06 or 0.125mg/kg, intra-cranial; 1 or 2μg/side), the muscarinic acetylcholine receptor (AChR) antagonist scopolamine (2.4 or 24μg/side), or the nicotinic AChR antagonist mecamylamine (3 or 30μg/side), prior to the FST test session. In control experiments, locomotor activity was also examined following systemic and intra-cranial administration of cholinergic drugs. Physostigmine administration, either systemically or directly into the VTA, significantly increased immobility time in FST, whereas physostigmine infusion into a dorsal control site did not alter immobility time. In contrast, VTA infusion of either scopolamine or mecamylamine decreased immobility time, consistent with an antidepressant-like effect. Finally, the VTA physostigmine-induced increase in immobility was blocked by co-administration with scopolamine, but unaltered by co-administration with mecamylamine. These data show that enhancing VTA cholinergic tone and blocking VTA AChRs has opposing effects in FST. Together, the findings provide evidence for a role of VTA cholinergic mechanisms in behavioral responses in FST. PMID:25865152

  1. Repeated swim impairs serotonin clearance via a corticosterone-sensitive mechanism: organic cation transporter 3, the smoking gun.

    PubMed

    Baganz, Nicole; Horton, Rebecca; Martin, Kathryn; Holmes, Andrew; Daws, Lynette C

    2010-11-10

    Activation of the hypothalamic-pituitary-adrenal (HPA) axis is associated with increased extracellular serotonin (5-HT) in limbic brain regions. The mechanism through which this occurs remains unclear. One way could be via HPA axis-dependent impairment of serotonin transporter (SERT) function, the high-affinity uptake mechanism for 5-HT. Consistent with this idea, we found that 5-HT clearance rate in hippocampus was dramatically reduced in mice exposed to repeated swim, a stimulus known to activate the HPA axis. However, this phenomenon also occurred in mice lacking SERT, ruling out SERT as a mechanism. The organic cation transporter 3 (OCT3) is emerging as an important regulator of brain 5-HT. Moreover, corticosterone, which is released upon HPA axis activation, blocks 5-HT uptake by OCT3. Repeated swim produced a persistent elevation in plasma corticosterone, and, consistent with prolonged blockade by corticosterone, we found that OCT3 expression and function were reduced in these mice. Importantly, this effect of repeated swim to reduce 5-HT clearance rate was corticosterone dependent, as evidenced by its absence in adrenalectomized mice, in which plasma corticosterone levels were essentially undetectable. Behaviorally, mice subjected to repeated swim spent less time immobile in the tail suspension test than control mice, but responded similarly to SERT- and norepinephrine transporter-selective antidepressants. Together, these results show that reduced 5-HT clearance following HPA axis activation is likely mediated, at least in part, by the corticosterone-sensitive OCT3, and that drugs developed to selectively target OCT3 (unlike corticosterone) may be candidates for the development of novel antidepressant medications. PMID:21068324

  2. Cholinergic mechanisms of analgesia produced by physostigmine, morphine and cold water swimming.

    PubMed

    Romano, J A; Shih, T M

    1983-07-01

    This study concerns the cholinergic involvement in three experimental procedures which produce analgesia. Rats were given one of seven treatments: saline (1.0 ml/kg, i.p.); morphine sulfate (3.5, 6.0 or 9.0 mg/kg, i.p.); physostigmine salicylate (0.65 mg/kg, i.p.); warm water swim (3.5 min at 28 degrees C); and cold water swim (3.5 min at 2 degrees C). Each rat was tested on a hot plate (59.1 degrees C) once prior to and 30 min after treatment. Immediately after the last test the rats were killed with focussed microwave radiation. Levels of acetylcholine (ACh) and choline (Ch) in six brain areas (brain stem, cerebral cortex, hippocampus, midbrain, cerebellum and striatum) were analyzed by gas chromatograph-mass spectrometer. Morphine (9.0 mg/kg), physostigmine and cold water swimming caused significant analgesia. Morphine elevated the levels of ACh in the cerebellum and striatum, cold water swimming--in the cerebellum, striatum and cortex, and physostigmine--in the striatum and hippocampus. Levels of choline were elevated by morphine in the cerebellum, cortex and hippocampus, while cold water swimming elevated levels of choline in the cerebellum, cortex, striatum and hippocampus. Physostigmine did not change levels of choline in any of the brain areas studied. These data suggest that the analgetic effects of morphine or cold water swimming may be mediated by components of the cholinergic system that differ from those involved in the analgetic effects of physostigmine. PMID:6621812

  3. A coordinated molecular 'fishing' mechanism in heterodimeric kinesin.

    PubMed

    Hou, Ruizheng; Wang, Zhisong

    2010-01-01

    Kar3 is a kinesin motor that facilitates chromosome segregation during cell division. Unlike many members of the kinesin superfamily, Kar3 forms a heterodimer with non-motor protein Vik1 or Cik1 in vivo. The heterodimers show ATP-driven minus-end directed motility along a microtubule (MT) lattice, and also serve as depolymerase at the MT ends. The molecular mechanisms behind this dual functionality remain mysterious. Here, a molecular mechanical model for the Kar3/Vik1 heterodimer based on structural, kinetic and motility data reveals a long-range chemomechanical transmission mechanism that resembles a familiar fishing tactic. By this molecular 'fishing', ATP-binding to Kar3 dissociates catalytically inactive Vik1 off MT to facilitate minus-end sliding of the dimer on the MT lattice. When the dimer binds the frayed ends of MT, the fishing channels ATP hydrolysis energy into MT depolymerization by a mechanochemical effect. The molecular fishing thus provides a unified mechanistic ground for Kar3's dual functionality. The fishing-promoted depolymerization differs from the depolymerase mechanisms found in homodimeric kinesins. The fishing also enables intermolecular coordination with a chemomechanical coupling feature different from the paradigmatic pattern of homodimeric motors. This study rationalizes some puzzling experimental observation, and suggests new experiments for further elucidation of the fishing mechanism. PMID:20720285

  4. Optimality Principles of Undulatory Swimming

    NASA Astrophysics Data System (ADS)

    Nangia, Nishant; Bale, Rahul; Patankar, Neelesh

    2015-11-01

    A number of dimensionless quantities derived from a fish's kinematic and morphological parameters have been used to describe the hydrodynamics of swimming. In particular, body/caudal fin swimmers have been found to swim within a relatively narrow range of these quantities in nature, e.g., Strouhal number or the optimal specific wavelength. It has been hypothesized or shown that these constraints arise due to maximization of swimming speed, efficiency, or cost of transport in certain domains of this large dimensionless parameter space. Using fully resolved simulations of undulatory patterns, we investigate the existence of various optimality principles in fish swimming. Using scaling arguments, we relate various dimensionless parameters to each other. Based on these findings, we make design recommendations on how kinematic parameters for a swimming robot or vehicle should be chosen. This work is supported by NSF Grants CBET-0828749, CMMI-0941674, CBET-1066575 and the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1324585.

  5. Identification of myogenic regulatory genes in the muscle transcriptome of beltfish (Trichiurus lepturus): A major commercial marine fish species with robust swimming ability.

    PubMed

    Zhang, Hui; Chang, Chung-Ming; Shen, Kang-Ning; Xian, Weiwei; Hsiao, Chung-Der

    2016-06-01

    The beltfish (Trichiurus lepturus) is considered as one of the most economically important marine fish in East Asia. It is a top predator with a robust swimming ability that is a good model to study muscle physiology in fish. In the present study, we used Illumina sequencing technology (NextSeq500) to sequence, assemble and annotate the muscle transcriptome of juvenile beltfish. A total of 57,509,280 clean reads (deposited in NCBI SRA database with accession number of SRX1674471) were obtained from RNA sequencing and 26,811 unigenes (with N50 of 1033 bp) were obtained after de novo assembling with Trinity software. BLASTX against NR, GO, KEGG and eggNOG databases show 100%, 49%, 31% and 96% annotation rate, respectively. By mining beltfish muscle transcriptome, several key genes which play essential role on regulating myogenesis, including pax3, pax7, myf5, myoD, mrf4/myf6, myogenin and myostatin were identified with a low expression level. The muscle transcriptome of beltfish can provide some insight into the understanding of genome-wide transcriptome profile of teleost muscle tissue and give useful information to study myogenesis in juvenile/adult fish. PMID:27222805

  6. Use of biorobotic models of highly deformable fins for studying the mechanics and control of fin forces in fishes.

    PubMed

    Tangorra, James; Phelan, Chris; Esposito, Chris; Lauder, George

    2011-07-01

    Bony fish swim with a level of agility that is unmatched in human-developed systems. This is due, in part, to the ability of the fish to carefully control hydrodynamic forces through the active modulation of the fins' kinematics and mechanical properties. To better understand how fish produce and control forces, biorobotic models of the bluegill sunfish's (Lepomis macrochirus) caudal fin and pectoral fins were developed. The designs of these systems were based on detailed analyses of the anatomy, kinematics, and hydrodynamics of the biological fins. The fin models have been used to investigate how fin kinematics and the mechanical properties of the fin-rays influence propulsive forces and to explore kinematic patterns that were inspired by biological motions but that were not explicitly performed by the fish. Results from studies conducted with the fin models indicate that subtle changes to the kinematics and mechanical properties of fin rays can significantly impact the magnitude, direction, and time course of the 3D forces used for propulsion and maneuvers. The magnitude of the force tends to scale with the fin's stiffness, but the direction of the force is not invariant, and this causes disproportional changes in the magnitude of the thrust, lift, and lateral components of force. Results from these studies shed light on the multiple strategies that are available to the fish to modulate fin forces. PMID:21653544

  7. The hydrodynamic advantages of synchronized swimming in a rectangular pattern.

    PubMed

    Daghooghi, Mohsen; Borazjani, Iman

    2015-10-01

    Fish schooling is a remarkable biological behavior that is thought to provide hydrodynamic advantages. Theoretical models have predicted significant reduction in swimming cost due to two physical mechanisms: vortex hypothesis, which reduces the relative velocity between fish and the flow through the induced velocity of the organized vortex structure of the incoming wake; and the channeling effect, which reduces the relative velocity by enhancing the flow between the swimmers in the direction of swimming. Although experimental observations confirm hydrodynamic advantages, there is still debate regarding the two mechanisms. We provide, to our knowledge, the first three-dimensional simulations at realistic Reynolds numbers to investigate these physical mechanisms. Using large-eddy simulations of self-propelled synchronized swimmers in various rectangular patterns, we find evidence in support of the channeling effect, which enhances the flow velocity between swimmers in the direction of swimming as the lateral distance between swimmers decreases. Our simulations show that the coherent structures, in contrast to the wake of a single swimmer, break down into small, disorganized vortical structures, which have a low chance for constructive vortex interaction. Therefore, the vortex hypothesis, which is relevant for diamond patterns, was not found for rectangular patterns, but needs to be further studied for diamond patterns in the future. Exploiting the channeling mechanism, a fish in a rectangular school swims faster as the lateral distance decreases, while consuming similar amounts of energy. The fish in the rectangular school with the smallest lateral distance (0.3 fish lengths) swims 20% faster than a solitary swimmer while consuming similar amount of energy. PMID:26447493

  8. Two-Swim Operators in the Modified Bacterial Foraging Algorithm for the Optimal Synthesis of Four-Bar Mechanisms.

    PubMed

    Hernández-Ocaña, Betania; Pozos-Parra, Ma Del Pilar; Mezura-Montes, Efrén; Portilla-Flores, Edgar Alfredo; Vega-Alvarado, Eduardo; Calva-Yáñez, Maria Bárbara

    2016-01-01

    This paper presents two-swim operators to be added to the chemotaxis process of the modified bacterial foraging optimization algorithm to solve three instances of the synthesis of four-bar planar mechanisms. One swim favors exploration while the second one promotes fine movements in the neighborhood of each bacterium. The combined effect of the new operators looks to increase the production of better solutions during the search. As a consequence, the ability of the algorithm to escape from local optimum solutions is enhanced. The algorithm is tested through four experiments and its results are compared against two BFOA-based algorithms and also against a differential evolution algorithm designed for mechanical design problems. The overall results indicate that the proposed algorithm outperforms other BFOA-based approaches and finds highly competitive mechanisms, with a single set of parameter values and with less evaluations in the first synthesis problem, with respect to those mechanisms obtained by the differential evolution algorithm, which needed a parameter fine-tuning process for each optimization problem. PMID:27057156

  9. Two-Swim Operators in the Modified Bacterial Foraging Algorithm for the Optimal Synthesis of Four-Bar Mechanisms

    PubMed Central

    Hernández-Ocaña, Betania; Pozos-Parra, Ma. Del Pilar; Mezura-Montes, Efrén; Portilla-Flores, Edgar Alfredo; Vega-Alvarado, Eduardo; Calva-Yáñez, Maria Bárbara

    2016-01-01

    This paper presents two-swim operators to be added to the chemotaxis process of the modified bacterial foraging optimization algorithm to solve three instances of the synthesis of four-bar planar mechanisms. One swim favors exploration while the second one promotes fine movements in the neighborhood of each bacterium. The combined effect of the new operators looks to increase the production of better solutions during the search. As a consequence, the ability of the algorithm to escape from local optimum solutions is enhanced. The algorithm is tested through four experiments and its results are compared against two BFOA-based algorithms and also against a differential evolution algorithm designed for mechanical design problems. The overall results indicate that the proposed algorithm outperforms other BFOA-based approaches and finds highly competitive mechanisms, with a single set of parameter values and with less evaluations in the first synthesis problem, with respect to those mechanisms obtained by the differential evolution algorithm, which needed a parameter fine-tuning process for each optimization problem. PMID:27057156

  10. Coping with the Forced Swim Stressor: Towards Understanding an Adaptive Mechanism

    PubMed Central

    de Kloet, E. R.; Molendijk, M. L.

    2016-01-01

    In the forced swim test (FST) rodents progressively show increased episodes of immobility if immersed in a beaker with water from where escape is not possible. In this test, a compound qualifies as a potential antidepressant if it prevents or delays the transition to this passive (energy conserving) behavioural style. In the past decade however the switch from active to passive “coping” was used increasingly to describe the phenotype of an animal that has been exposed to a stressful history and/or genetic modification. A PubMed analysis revealed that in a rapidly increasing number of papers (currently more than 2,000) stress-related immobility in the FST is labeled as a depression-like phenotype. In this contribution we will examine the different phases of information processing during coping with the forced swim stressor. For this purpose we focus on the action of corticosterone that is mediated by the closely related mineralocorticoid receptors (MR) and glucocorticoid receptors (GR) in the limbic brain. The evidence available suggests a model in which we propose that the limbic MR-mediated response selection operates in complementary fashion with dopaminergic accumbens/prefrontal executive functions to regulate the transition between active and passive coping styles. Upon rescue from the beaker the preferred, mostly passive, coping style is stored in the memory via a GR-dependent action in the hippocampal dentate gyrus. It is concluded that the rodent's behavioural response to a forced swim stressor does not reflect depression. Rather the forced swim experience provides a unique paradigm to investigate the mechanistic underpinning of stress coping and adaptation. PMID:27034848

  11. Coping with the Forced Swim Stressor: Towards Understanding an Adaptive Mechanism.

    PubMed

    de Kloet, E R; Molendijk, M L

    2016-01-01

    In the forced swim test (FST) rodents progressively show increased episodes of immobility if immersed in a beaker with water from where escape is not possible. In this test, a compound qualifies as a potential antidepressant if it prevents or delays the transition to this passive (energy conserving) behavioural style. In the past decade however the switch from active to passive "coping" was used increasingly to describe the phenotype of an animal that has been exposed to a stressful history and/or genetic modification. A PubMed analysis revealed that in a rapidly increasing number of papers (currently more than 2,000) stress-related immobility in the FST is labeled as a depression-like phenotype. In this contribution we will examine the different phases of information processing during coping with the forced swim stressor. For this purpose we focus on the action of corticosterone that is mediated by the closely related mineralocorticoid receptors (MR) and glucocorticoid receptors (GR) in the limbic brain. The evidence available suggests a model in which we propose that the limbic MR-mediated response selection operates in complementary fashion with dopaminergic accumbens/prefrontal executive functions to regulate the transition between active and passive coping styles. Upon rescue from the beaker the preferred, mostly passive, coping style is stored in the memory via a GR-dependent action in the hippocampal dentate gyrus. It is concluded that the rodent's behavioural response to a forced swim stressor does not reflect depression. Rather the forced swim experience provides a unique paradigm to investigate the mechanistic underpinning of stress coping and adaptation. PMID:27034848

  12. Mechanical models of sandfish locomotion reveal principles of high performance subsurface sand-swimming

    PubMed Central

    Maladen, Ryan D.; Ding, Yang; Umbanhowar, Paul B.; Kamor, Adam; Goldman, Daniel I.

    2011-01-01

    We integrate biological experiment, empirical theory, numerical simulation and a physical model to reveal principles of undulatory locomotion in granular media. High-speed X-ray imaging of the sandfish lizard, Scincus scincus, in 3 mm glass particles shows that it swims within the medium without using its limbs by propagating a single-period travelling sinusoidal wave down its body, resulting in a wave efficiency, η, the ratio of its average forward speed to the wave speed, of approximately 0.5. A resistive force theory (RFT) that balances granular thrust and drag forces along the body predicts η close to the observed value. We test this prediction against two other more detailed modelling approaches: a numerical model of the sandfish coupled to a discrete particle simulation of the granular medium, and an undulatory robot that swims within granular media. Using these models and analytical solutions of the RFT, we vary the ratio of undulation amplitude to wavelength (A/λ) and demonstrate an optimal condition for sand-swimming, which for a given A results from the competition between η and λ. The RFT, in agreement with the simulated and physical models, predicts that for a single-period sinusoidal wave, maximal speed occurs for A/λ ≈ 0.2, the same kinematics used by the sandfish. PMID:21378020

  13. Mechanisms of cortisol action in fish hepatocytes.

    PubMed

    Faught, Erin; Vijayan, Mathilakath M

    2016-09-01

    Here we provide an overview of the mechanistic characterization of the hepatic action of cortisol during stress in fish. Cortisol is the main circulating glucocorticoid in fish and its action is mediated through its cytosolic receptor, the glucocorticoid receptor (GR), and regulates the expression of genes involved in growth, metabolism and immune function. When taken together, the data suggests that cortisol may be playing a key role in the energy substrate re-partitioning in hepatocytes to cope with stress. The proposed model is that cortisol upregulates pathways involved in energy substrate mobilization, including gluconeogenesis, while downregulating energy demanding pathways, including growth and immune function. Recent work also points to a role for cortisol in mediating rapid action that is non-genomic and includes modulation of secondary signalling cascades; however, the physiological relevance of these studies remains to be determined. Altogether, studies carried out in hepatocytes are bringing to fore the complex nature of the cortisol signalling pathways in the organismal stress response. The mode of actions and their physiological implications for stress coping awaits further study. PMID:27445122

  14. Automatic Realistic Real Time Stimulation/Recording in Weakly Electric Fish: Long Time Behavior Characterization in Freely Swimming Fish and Stimuli Discrimination

    PubMed Central

    Forlim, Caroline G.; Pinto, Reynaldo D.

    2014-01-01

    Weakly electric fish are unique model systems in neuroethology, that allow experimentalists to non-invasively, access, central nervous system generated spatio-temporal electric patterns of pulses with roles in at least 2 complex and incompletely understood abilities: electrocommunication and electrolocation. Pulse-type electric fish alter their inter pulse intervals (IPIs) according to different behavioral contexts as aggression, hiding and mating. Nevertheless, only a few behavioral studies comparing the influence of different stimuli IPIs in the fish electric response have been conducted. We developed an apparatus that allows real time automatic realistic stimulation and simultaneous recording of electric pulses in freely moving Gymnotus carapo for several days. We detected and recorded pulse timestamps independently of the fish’s position for days. A stimulus fish was mimicked by a dipole electrode that reproduced the voltage time series of real conspecific according to previously recorded timestamp sequences. We characterized fish behavior and the eletrocommunication in 2 conditions: stimulated by IPIs pre-recorded from other fish and random IPI ones. All stimuli pulses had the exact Gymontus carapo waveform. All fish presented a surprisingly long transient exploratory behavior (more than 8 h) when exposed to a new environment in the absence of electrical stimuli. Further, we also show that fish are able to discriminate between real and random stimuli distributions by changing several characteristics of their IPI distribution. PMID:24400122

  15. Female "Big Fish" Swimming against the Tide: The "Big-Fish-Little-Pond Effect" and Gender-Ratio in Special Gifted Classes

    ERIC Educational Resources Information Center

    Preckel, Franzis; Zeidner, Moshe; Goetz, Thomas; Schleyer, Esther Jane

    2008-01-01

    This study takes a second look at the "big-fish-little-pond effect" (BFLPE) on a national sample of 769 gifted Israeli students (32% female) previously investigated by Zeidner and Schleyer (Zeidner, M., & Schleyer, E. J., (1999a). "The big-fish-little-pond effect for academic self-concept, test anxiety, and school grades in gifted children."…

  16. Swimming performance and energy homeostasis in juvenile laboratory raised fathead minnow (Pimephales promelas) exposed to uranium mill effluent.

    PubMed

    Goertzen, Meghan M; Driessnack, Melissa K; Janz, David M; Weber, Lynn P

    2011-11-01

    Research at the Key Lake uranium mill (Saskatchewan, Canada) suggests effluent discharged from the mill affects energy stores of resident fish, but the mechanisms by which energy homeostasis is affected and the subsequent effects on swimming performance are unknown. In the present study larvae were collected from laboratory raised adult fathead minnow (Pimephales promelas) exposed to 5% diluted uranium mill effluent or control (dechlorinated municipal) water, and reared in the same treatments to 60 days post hatch (dph). Critical swimming speed (U(crit)) was significantly lower in effluent exposed 60 dph fish compared to control fish. Fish used in tests were considered fatigued and compared to fish without swim testing (non-fatigued). There were no differences in whole body glycogen or triglyceride concentrations between effluent exposed versus control fish. However, fatigued fish from both treatments had significantly lower triglycerides, but not glycogen, compared to non-fatigued fish from the same treatment. Whole body β-hydroxyacyl coenzymeA dehydrogenase activity was similar in fish from both treatments, but citrate synthase activity was significantly lower in effluent exposed fish. Our results suggest uranium mill effluent exposure in the laboratory affects aerobic energy metabolism and swimming performance in juvenile fathead minnow, which could affect wild fish survivability. PMID:21839854

  17. Seahorses under a changing ocean: the impact of warming and acidification on the behaviour and physiology of a poor-swimming bony-armoured fish.

    PubMed

    Faleiro, Filipa; Baptista, Miguel; Santos, Catarina; Aurélio, Maria L; Pimentel, Marta; Pegado, Maria Rita; Paula, José Ricardo; Calado, Ricardo; Repolho, Tiago; Rosa, Rui

    2015-01-01

    Seahorses are currently facing great challenges in the wild, including habitat degradation and overexploitation, and how they will endure additional stress from rapid climate change has yet to be determined. Unlike most fishes, the poor swimming skills of seahorses, along with the ecological and biological constraints of their unique lifestyle, place great weight on their physiological ability to cope with climate changes. In the present study, we evaluate the effects of ocean warming (+4°C) and acidification (ΔpH = -0.5 units) on the physiological and behavioural ecology of adult temperate seahorses, Hippocampus guttulatus. Adult seahorses were found to be relatively well prepared to face future changes in ocean temperature, but not the combined effect of warming and acidification. Seahorse metabolism increased normally with warming, and behavioural and feeding responses were not significantly affected. However, during hypercapnia the seahorses exhibited signs of lethargy (i.e. reduced activity levels) combined with a reduction of feeding and ventilation rates. Nonetheless, metabolic rates were not significantly affected. Future ocean changes, particularly ocean acidification, may further threaten seahorse conservation, turning these charismatic fishes into important flagship species for global climate change issues. PMID:27293694

  18. Seahorses under a changing ocean: the impact of warming and acidification on the behaviour and physiology of a poor-swimming bony-armoured fish

    PubMed Central

    Faleiro, Filipa; Baptista, Miguel; Santos, Catarina; Aurélio, Maria L.; Pimentel, Marta; Pegado, Maria Rita; Paula, José Ricardo; Calado, Ricardo; Repolho, Tiago; Rosa, Rui

    2015-01-01

    Seahorses are currently facing great challenges in the wild, including habitat degradation and overexploitation, and how they will endure additional stress from rapid climate change has yet to be determined. Unlike most fishes, the poor swimming skills of seahorses, along with the ecological and biological constraints of their unique lifestyle, place great weight on their physiological ability to cope with climate changes. In the present study, we evaluate the effects of ocean warming (+4°C) and acidification (ΔpH = −0.5 units) on the physiological and behavioural ecology of adult temperate seahorses, Hippocampus guttulatus. Adult seahorses were found to be relatively well prepared to face future changes in ocean temperature, but not the combined effect of warming and acidification. Seahorse metabolism increased normally with warming, and behavioural and feeding responses were not significantly affected. However, during hypercapnia the seahorses exhibited signs of lethargy (i.e. reduced activity levels) combined with a reduction of feeding and ventilation rates. Nonetheless, metabolic rates were not significantly affected. Future ocean changes, particularly ocean acidification, may further threaten seahorse conservation, turning these charismatic fishes into important flagship species for global climate change issues. PMID:27293694

  19. Novel design solutions for fishing reel mechanisms

    NASA Astrophysics Data System (ADS)

    Lovasz, Erwin-Christian; Modler, Karl-Heinz; Neumann, Rudolf; Gruescu, Corina Mihaela; Perju, Dan; Ciupe, Valentin; Maniu, Inocentiu

    2015-07-01

    Currently, there are various reels on the market regarding the type of mechanism, which achieves the winding and unwinding of the line. The designers have the purpose of obtaining a linear transmission function, by means of a simple and small-sized mechanism. However, the present solutions are not satisfactory because of large deviations from linearity of the transmission function and complexity of mechanical schema. A novel solution for the reel spool mechanism is proposed. Its kinematic schema and synthesis method are described. The kinematic schema of the chosen mechanism is based on a noncircular gear in series with a scotch-yoke mechanism. The yoke is driven by a stud fixed on the driving noncircular gear. The drawbacks of other models regarding the effects occurring at the ends of the spool are eliminated through achieving an appropriate transmission function of the spool. The linear function approximation with curved end-arches appropriately computed to ensure mathematical continuity is very good. The experimental results on the mechanism model validate the theoretical approach. The developed mechanism solution is recorded under a reel spool mechanism patent.

  20. Fish and chips: implementation of a neural network model into computer chips to maximize swimming efficiency in autonomous underwater vehicles.

    PubMed

    Blake, R W; Ng, H; Chan, K H S; Li, J

    2008-09-01

    Recent developments in the design and propulsion of biomimetic autonomous underwater vehicles (AUVs) have focused on boxfish as models (e.g. Deng and Avadhanula 2005 Biomimetic micro underwater vehicle with oscillating fin propulsion: system design and force measurement Proc. 2005 IEEE Int. Conf. Robot. Auto. (Barcelona, Spain) pp 3312-7). Whilst such vehicles have many potential advantages in operating in complex environments (e.g. high manoeuvrability and stability), limited battery life and payload capacity are likely functional disadvantages. Boxfish employ undulatory median and paired fins during routine swimming which are characterized by high hydromechanical Froude efficiencies (approximately 0.9) at low forward speeds. Current boxfish-inspired vehicles are propelled by a low aspect ratio, 'plate-like' caudal fin (ostraciiform tail) which can be shown to operate at a relatively low maximum Froude efficiency (approximately 0.5) and is mainly employed as a rudder for steering and in rapid swimming bouts (e.g. escape responses). Given this and the fact that bioinspired engineering designs are not obligated to wholly duplicate a biological model, computer chips were developed using a multilayer perception neural network model of undulatory fin propulsion in the knifefish Xenomystus nigri that would potentially allow an AUV to achieve high optimum values of propulsive efficiency at any given forward velocity, giving a minimum energy drain on the battery. We envisage that externally monitored information on flow velocity (sensory system) would be conveyed to the chips residing in the vehicle's control unit, which in turn would signal the locomotor unit to adopt kinematics (e.g. fin frequency, amplitude) associated with optimal propulsion efficiency. Power savings could protract vehicle operational life and/or provide more power to other functions (e.g. communications). PMID:18626130

  1. Biofluid Mechanics

    NASA Astrophysics Data System (ADS)

    Oertel, Herbert

    In contrast to the topics discussed in previous chapters, biofluid mechanics is concerned with flows that are influenced by flexible biological surfaces. We distinguish between flows past living bodies in air or in water, such as bird flight or the swimming of fish, and internal flows, such as the closed blood circulation of living beings. In the previous millions of years, evolution has developed crawling, running, swimming, gliding, and flying as methods of motion of living beings, depending on their size and weight.

  2. Role of Flexibility in Thrust Production of a Mechanical Swimming Lamprey

    NASA Astrophysics Data System (ADS)

    Leftwich, Megan; Smits, Alexander

    2009-11-01

    To develop a comprehensive model of lamprey locomotion, we use a robotic lamprey as a means of investigating the wake structure during swimming with an anatomically designed tail of varying degrees of flexibility. A programmable microcomputer actuates 11 servomotors that produce a traveling wave along the length of the lamprey body. The waveform is based on kinematic studies of living lamprey. The shape of the tail is taken from CT scan data of the silver lamprey, and it is constructed of flexible PVC gel. Plastic inserts allow the the degree of flexibility to be changed. PIV measurements in the wake behind the most flexible tail show a 2P wake structure that quickly looses coherence as it is convected downstream. This is in contrast to the strongly coherent and symmetrical 2P wake seen in previous experiments using a rigid, rectangular tail. The project is supported by NIH CNRS Grant 1R01NS054271.

  3. Similarities and Differences for Swimming in Larval and Adult Lampreys.

    PubMed

    McClellan, Andrew D; Pale, Timothée; Messina, J Alex; Buso, Scott; Shebib, Ahmad

    2016-01-01

    The spinal locomotor networks controlling swimming behavior in larval and adult lampreys may have some important differences. As an initial step in comparing the locomotor systems in lampreys, in larval animals the relative timing of locomotor movements and muscle burst activity were determined and compared to those previously published for adults. In addition, the kinematics for free swimming in larval and adult lampreys was compared in detail for the first time. First, for swimming in larval animals, the neuromechanical phase lag between the onsets or terminations of muscle burst activity and maximum concave curvature of the body increased with increasing distance along the body, similar to that previously shown in adults. Second, in larval lampreys, but not adults, absolute swimming speed (U; mm s(-1)) increased with animal length (L). In contrast, normalized swimming speed (U'; body lengths [bl] s(-1)) did not increase with L in larval or adult animals. In both larval and adult lampreys, U' and normalized wave speed (V') increased with increasing tail-beat frequency. Wavelength and mechanical phase lag did not vary significantly with tail-beat frequency but were significantly different in larval and adult animals. Swimming in larval animals was characterized by a smaller U/V ratio, Froude efficiency, and Strouhal number than in adults, suggesting less efficient swimming for larval animals. In addition, during swimming in larval lampreys, normalized lateral head movements were larger and normalized lateral tail movements were smaller than for adults. Finally, larval animals had proportionally smaller lateral surface areas of the caudal body and fin areas than adults. These differences are well suited for larval sea lampreys that spend most of the time buried in mud/sand, in which swimming efficiency is not critical, compared to adults that would experience significant selection pressure to evolve higher-efficiency swimming to catch up to and attach to fish for

  4. Stochastic and Deterministic Flagellar Dynamics Provide a Mechanism for Eukaryotic Swimming Reorientation

    NASA Astrophysics Data System (ADS)

    Polin, Marco; Tuval, Idan; Drescher, Knut; Goldstein, Raymond

    2009-03-01

    The biflagellated alga Chlamydomonas reinhardtii is a good model organism to study the origin of flagellar synchronization. Here we employ high-speed imaging to study the beating of the two flagella of Chlamydomonas, and show that a single cell can alternate between two distinct dynamical regimes: asynchronous and synchronous. The asynchronous state is characterized by a large interflagellar frequency difference. In the synchronous state, the flagella beat in phase for lengthy periods, interrupted episodically by an extra beat of either flagellum. The statistics of these events are consistent with a model of hydrodynamically coupled noisy oscillators. Previous observations have suggested that the two flagella have well separated intrinsic beat frequencies, and are synchronized by their mutual coupling. Our analysis shows instead that the synchronized state is incompatible with coupling-induced synchronization of flagella with those intrinsic frequencies. This suggests that the beat frequencies themselves are under the control of the cell. Moreover, high-resolution three-dimensional tracking of swimming cells provides strong evidence that these dynamical states are related to non-phototactic reorientation events in the trajectories, yielding a eukaryotic equivalent of the ``run and tumble'' motion of peritrichously flagellated bacteria.

  5. Flexibility and Resonance in Thrust Production of a Mechanical Swimming Lamprey

    NASA Astrophysics Data System (ADS)

    Leftwich, Megan; Smits, Alexander

    2010-11-01

    We use a robotic lamprey as a means of investigating the influence of flexibility on the wake structure and thrust production during anguilliform swimming. A programmable microcomputer actuates 11 servomotors that produce a traveling wave along the length of the lamprey body. The waveform is based on kinematic studies of living lamprey. The shape of the tail is taken from CT scan data of the silver lamprey, and it is constructed of flexible PVC gel. Plastic inserts allow the the degree of flexibility to be changed. PIV measurements in the wake of the robot with three different flexible tails show that a 2P structure dominates the flexible wake. However, the large structure is composed of several small vortices (as opposed to the large coherent vortex seen behind a stiff tailed robot). Furthermore, the wake loses coherence as flexibility is increased. Additionally, momentum balance calculations indicate that increasing the tail flexibility yields less thrust. Finally, we find that changing the cycle frequency to match the resonance frequency of the tail increases the thrust production. The project is supported by NIH CNRS Grant 1R01NS054271.

  6. Factors affecting swimming performance of fasted rainbow trout with implications of exhaustive exercise on overwinter mortality

    USGS Publications Warehouse

    Simpkins, D.G.; Hubert, W.A.; Del Rio, C.M.; Rule, D.C.

    2004-01-01

    We evaluated the effects of body size, water temperature, and sustained swimming activity on swimming performance and the effects of exhaustive exercise on mortality of fasted juvenile rainbow trout. Fasting caused swimming performance to decline more rapidly for small fish than large fish, and warmer water temperatures and sustained swimming activity further decreased swimming performance. Exhaustive exercise increased mortality among fasted fish. Our observations suggest that juvenile rainbow trout with little or no food intake during winter can swim for long periods of time with little effect on mortality, but swimming to exhaustion can enhance mortality, especially among the smallest juveniles.

  7. Red fluorescence in reef fish: A novel signalling mechanism?

    PubMed Central

    Michiels, Nico K; Anthes, Nils; Hart, Nathan S; Herler, Jürgen; Meixner, Alfred J; Schleifenbaum, Frank; Schulte, Gregor; Siebeck, Ulrike E; Sprenger, Dennis; Wucherer, Matthias F

    2008-01-01

    Background At depths below 10 m, reefs are dominated by blue-green light because seawater selectively absorbs the longer, 'red' wavelengths beyond 600 nm from the downwelling sunlight. Consequently, the visual pigments of many reef fish are matched to shorter wavelengths, which are transmitted better by water. Combining the typically poor long-wavelength sensitivity of fish eyes with the presumed lack of ambient red light, red light is currently considered irrelevant for reef fish. However, previous studies ignore the fact that several marine organisms, including deep sea fish, produce their own red luminescence and are capable of seeing it. Results We here report that at least 32 reef fishes from 16 genera and 5 families show pronounced red fluorescence under natural, daytime conditions at depths where downwelling red light is virtually absent. Fluorescence was confirmed by extensive spectrometry in the laboratory. In most cases peak emission was around 600 nm and fluorescence was associated with guanine crystals, which thus far were known for their light reflecting properties only. Our data indicate that red fluorescence may function in a context of intraspecific communication. Fluorescence patterns were typically associated with the eyes or the head, varying substantially even between species of the same genus. Moreover red fluorescence was particularly strong in fins that are involved in intraspecific signalling. Finally, microspectrometry in one fluorescent goby, Eviota pellucida, showed a long-wave sensitivity that overlapped with its own red fluorescence, indicating that this species is capable of seeing its own fluorescence. Conclusion We show that red fluorescence is widespread among marine fishes. Many features indicate that it is used as a private communication mechanism in small, benthic, pair- or group-living fishes. Many of these species show quite cryptic colouration in other parts of the visible spectrum. High inter-specific variation in red

  8. Fish gotta swim, Birds gotta fly, I gotta do Feynmann Graphs 'til I die: A continuum Theory of Flocking

    NASA Astrophysics Data System (ADS)

    Toner, John; Tu, Yu-Hai

    2002-05-01

    We have developed a new continuum dynamical model for the collective motion of large "flocks" of biological organisms (e.g., flocks of birds, schools of fish, herds of wildebeest, hordes of bacteria, slime molds, etc.) . This model does for flocks what the Navier-Stokes equation does for fluids. The model predicts that, unlike simple fluids, flocks show huge fluctuation effects in spatial dimensions d < 4 that radically change their behavior. In d=2, it is only these effects that make it possible for the flock to move coherently at all. This explains why a million wildebeest can march together across the Serengeti plain, despite the fact that a million physicists gathered on the same plane could NOT all POINT in the same direction. Detailed quantitative predictions of this theory agree beautifully with computer simulations of flock motion.

  9. Long lasting increase in nociceptive threshold induced in mice by forced swimming: involvement of an endorphinergic mechanism.

    PubMed

    Suaudeau, C; Costentin, J

    2000-05-01

    Mice submitted to forced swimming session(s) displayed a long lasting modification in their nociceptive threshold, assessed through their jump latency from a hot plate (55 degrees C). Thus two forced swimming sessions (6 min each, 8h apart), in water at 33 degrees C, increased by about 50% the jump latency when the hot plate test was performed 14 hours, 3 days or 6 days thereafter. The water temperature (16 degrees C vs 33 degrees C) had no critical influence in this respect. To be clearly effective (at 33 degrees C) the swimming session had to be performed twice (when performed only once it was irregularly effective); it apparently culminated for a 6 min duration, since its effectiveness was not significantly increased by extending the swimming time to 12 min or 18 min. Performing 2 forced swimming sessions (6 min each, 8h apart), 5 consecutive days, resulted in a suppression of the increase in jump latency in the hot plate test. The two forced swimming episodes-induced analgesia was prevented by the s.c. administration of diazepam (from 0.125 mg/kg) or morphine (from 5 mg/kg) or scopolamine (1 mg/kg) before each forced swimming episode. Morphine (7.5 mg/kg) was uneffective to prevent the induction of two forced swimming episodes-induced analgesia when it was administered immediately after each forced swimming session. Finally this analgesia was dose dependently reversed by naloxone (ID(50) = 0.14 mg/kg, s.c., 30 min before the hot plate test). It is hypothesized that the handling of mice immediately before the hot plate test induces the remembrance of the stress induced by previous forced swimming episodes, triggering a fear reaction which increases the nociceptive threshold. PMID:10938583

  10. Timing reproduction in teleost fish: cues and mechanisms.

    PubMed

    Juntti, Scott A; Fernald, Russell D

    2016-06-01

    Fish comprise half of extant vertebrate species and use a rich variety of reproductive strategies that have yielded insights into the basic mechanisms that evolved for sex. To maximize the chances of fertilization and survival of offspring, fish species time reproduction to occur at optimal times. For years, ethologists have performed painstaking experiments to identify sensory inputs and behavioral outputs of the brain during mating. Here we review known mechanisms that generate sexual behavior, focusing on the factors that govern the timing of these displays. The development of new technologies, including high-throughput sequencing and genome engineering, has the potential to provide novel insights into how the vertebrate brain consummates mating at the appropriate time. PMID:26952366

  11. Cruise and turning performance of an improved fish robot actuated by piezoceramic actuators

    NASA Astrophysics Data System (ADS)

    Nguyen, Quang Sang; Heo, Seok; Park, Hoon Cheol; Goo, Nam Seo; Byun, Doyoung

    2009-03-01

    The purpose of this study is improvement of a fish robot actuated by four light-weight piezocomposite actuators (LIPCAs). In the fish robot, we developed a new actuation mechanism working without any gear and thus the actuation mechanism was simple in fabrication. By using the new actuation mechanism, cross section of the fish robot became 30% smaller than that of the previous model. Performance tests of the fish robot in water were carried out to measure tail-beat angle, thrust force, swimming speed and turning radius for tail-beat frequencies from 1Hz to 5Hz. The maximum swimming speed of the fish robot was 7.7 cm/s at 3.9Hz tail-beat frequency. Turning experiment showed that swimming direction of the fish robot could be controlled with 0.41 m turning radius by controlling tail-beat angle.

  12. Swim pressure of active matter

    NASA Astrophysics Data System (ADS)

    Takatori, Sho; Yan, Wen; Brady, John; Caltech Team

    2014-11-01

    Through their self-motion, all active matter systems generate a unique ``swim pressure'' that is entirely athermal in origin. This new source for the active stress exists at all scales in both living and nonliving active systems, and also applies to larger organisms where inertia is important (i.e., the Stokes number is not small). Here we explain the origin of the swim stress and develop a simple thermodynamic model to study the self-assembly and phase separation in active soft matter. Our new swim stress perspective can help analyze and exploit a wide class of active soft matter, from swimming bacteria and catalytic nanobots, schools of fish and birds, and molecular motors that activate the cellular cytoskeleton.

  13. The Swim Pressure of Active Matter

    NASA Astrophysics Data System (ADS)

    Brady, John; Takatori, Sho; Yan, Wen

    2015-03-01

    Through their self-motion, active matter systems generate a unique ``swim pressure'' that is entirely athermal in origin. This new source for the active stress exists at all scales in both living and nonliving active systems, and also applies to larger organisms where inertia is important. Here we explain the origin of the swim stress and develop a simple thermodynamic model to study the self-assembly and phase separation in active soft matter. Our new swim stress perspective may help analyze and exploit a wide class of active soft matter, from swimming bacteria and catalytic nanobots, schools of fish and birds, and molecular motors that activate the cellular cytoskeleton.

  14. Swimming Pools.

    ERIC Educational Resources Information Center

    Ministry of Housing and Local Government, London (England).

    Technical and engineering data are set forth on the design and construction of swimming pools. Consideration is given to site selection, pool construction, the comparative merits of combining open air and enclosed pools, and alternative uses of the pool. Guidelines are presented regarding--(1) pool size and use, (2) locker and changing rooms, (3)…

  15. Performance evaluation of an improved fish robot actuated by piezoceramic actuators

    NASA Astrophysics Data System (ADS)

    Nguyen, Q. S.; Heo, S.; Park, H. C.; Byun, D.

    2010-03-01

    This paper presents an improved fish robot actuated by four lightweight piezocomposite actuators. Our newly developed actuation mechanism is simple to fabricate because it works without gears. With the new actuation mechanism, the fish robot has a 30% smaller cross section than our previous model. Performance tests of the fish robot in water were carried out to measure the tail-beat angle, the thrust force, the swimming speed for various tail-beat frequencies from 1 to 5 Hz and the turning radius at the optimal frequency. The maximum swimming speed of the fish robot is 7.7 cm s - 1 at a tail-beat frequency of 3.9 Hz. A turning experiment shows that the swimming direction of the fish robot can be controlled by changing the duty ratio of the driving voltage; the fish robot has a turning radius of 0.41 m for a left turn and 0.68 m for a right turn.

  16. Quercetin Inhibits Peripheral and Spinal Cord Nociceptive Mechanisms to Reduce Intense Acute Swimming-Induced Muscle Pain in Mice.

    PubMed

    Borghi, Sergio M; Pinho-Ribeiro, Felipe A; Fattori, Victor; Bussmann, Allan J C; Vignoli, Josiane A; Camilios-Neto, Doumit; Casagrande, Rubia; Verri, Waldiceu A

    2016-01-01

    The present study aimed to evaluate the effects of the flavonoid quercetin (3,3´,4´,5,7-pentahydroxyflavone) in a mice model of intense acute swimming-induced muscle pain, which resembles delayed onset muscle soreness. Quercetin intraperitoneal (i.p.) treatment dose-dependently reduced muscle mechanical hyperalgesia. Quercetin inhibited myeloperoxidase (MPO) and N-acetyl-β-D- glucosaminidase (NAG) activities, cytokine production, oxidative stress, cyclooxygenase-2 (COX-2) and gp91phox mRNA expression and muscle injury (creatinine kinase [CK] blood levels and myoblast determination protein [MyoD] mRNA expression) as well as inhibited NFκB activation and induced Nrf2 and HO-1 mRNA expression in the soleus muscle. Beyond inhibiting those peripheral effects, quercetin also inhibited spinal cord cytokine production, oxidative stress and glial cells activation (glial fibrillary acidic protein [GFAP] and ionized calcium-binding adapter molecule 1 [Iba-1] mRNA expression). Concluding, the present data demonstrate that quercetin is a potential molecule for the treatment of muscle pain conditions related to unaccustomed exercise. PMID:27583449

  17. Fluid dynamics: Swimming across scales

    NASA Astrophysics Data System (ADS)

    Baumgart, Johannes; Friedrich, Benjamin M.

    2014-10-01

    The myriad creatures that inhabit the waters of our planet all swim using different mechanisms. Now, a simple relation links key physical observables of underwater locomotion, on scales ranging from millimetres to tens of metres.

  18. An integrated muscle mechanic-fluid dynamic model of lamprey swimming

    NASA Astrophysics Data System (ADS)

    Hsu, Chia-Yu; Tytell, Eric; Fauci, Lisa

    2009-11-01

    In an effort towards a detailed understanding of the generation and control of vertebrate locomotion, including the role of the CPG and its interactions with reflexive feedback, muscle mechanics, and external fluid dynamics, we study a simple vertebrate, the lamprey. Lamprey body undulations are a result of a wave of neural activation that passes from head to tail, causing a wave of muscle activation. These active forces are mediated by passive structural forces. We present recent results from a model that fully couples a viscous, incompressible fluid with nonlinear muscle mechanics. We measure the dependence of the phase lag between activation wave and mechanical wave as a function of model parameters, such as body stiffness and muscle strength. Simulation results are compared to experiments utilizing both real and synthetic lamprey.

  19. Swimming capability and swimming behavior of juvenile acipenser schrenckii.

    PubMed

    Cai, Lu; Taupier, Rachel; Johnson, David; Tu, Zhiying; Liu, Guoyong; Huang, Yingping

    2013-03-01

    Acipenser schrenckii, the Amur Sturgeon, was a commercially valuable fish species inhabiting the Amur (Heilongjiang) River but populations have rapidly declined in recent years. Dams impede A. schrenckii spawning migration and wild populations were critically endangered. Building fishways helped maintain fish populations but data on swimming performance and behavior was crucial for fishway design. To obtain such data on A. schrenckii, a laboratory study of juvenile A. schrenckii (n = 18, body mass = 32.7 ± 1.2 g, body length = 18.8 ± 0.3 cm) was conducted using a stepped velocity test carried out in a fish respirometer equipped with a high-speed video camera at 20°C. Results indicate: (1) The counter-current swimming capability of A. schrenckii was low with critical swimming speed of 1.96 ± 0.10 BL/sec. (2) When a linear function was fitted to the data, oxygen consumption, as a function of swimming speed, was determined to be MO2  = 337.29 + 128.10U (R(2)  = 0.971, P < 0.001) and the power value (1.0) of U indicated high swimming efficiency. (3) Excess post-exercise oxygen cost was 48.44 mgO2 /kg and indicated excellent fatigue recovery. (4) Cost of transport decreased slowly with increased swimming speed. (5) Increased swimming speed led to increases in the tail beat frequency and stride length. This investigation contributed to the basic science of fish swimming behavior and provided data required for the design of fishways. Innovative methods have allowed cultivation of the species in the Yangtze River and, if effective fishways could be incorporated into the design of future hydropower projects on the Amur River, it would contribute to conservation of wild populations of A. schrenckii. The information provided here contributes to the international effort to save this critically endangered species. J. Exp. Zool. 319A:149-155, 2013. © 2013 Wiley Periodicals, Inc. PMID:23359615

  20. Swimming Lessons

    ERIC Educational Resources Information Center

    Goldman, Arthur

    2006-01-01

    In this article, the author talks about his experience as an 11-year-old swimmer and shares the lessons he learned as a member of the swim team. In his experience as one of the slowest team members, he discovered that slow and steady does not win the race, and when the focus is only on achievement, one loses the value of failure. As an adult, he…

  1. Critical swimming speeds of wild bull trout

    USGS Publications Warehouse

    Mesa, M.G.; Weiland, L.K.; Zydlewski, G.B.

    2004-01-01

    We estimated the critical swimming speeds (Ucrit) of wild bull trout at 6??, 11??, and 15??C in laboratory experiments. At 11??C, 5 fish ranging from 11 to 19 cm in length had a mean Ucrit of 48.24 cm/s or 3.22 body lengths per second (BL/s). Also at 11??C , 6 fish from 32 to 42 cm had a mean Ucrit of 73.99 cm/s or 2.05 BL/s. At 15??C, 5 fish from 14 to 23 cm had a mean Ucrit of 54.66 cm/s or 2.88 BL/s. No fish successfully swam at 6??C. Swim speed was significantly influenced by fish length. Many bull trout performed poorly in our enclosed respirometers: of 71 Ucrit tests we attempted, only the 16 described above were successful. Bull trout that refused to swim held station within tunnels by using their pectoral fins as depressors, or they rested and later became impinged against a downstream screen. Several common techniques did not stimulate consistent swimming activity in these fish. Our estimates of U crit for bull trout provide an understanding of their performance capacity and will be useful in modeling efforts aimed at improving fish passage structures. We recommend that fishway or culvert designers concerned with bull trout passage maintain velocities within their structures at or below our estimates of Ucrit, thus taking a conservative approach to ensuring that these fish can ascend migratory obstacles safely.

  2. Dynamics of the vortex wakes of flying and swimming vertebrates.

    PubMed

    Rayner, J M

    1995-01-01

    The vortex wakes of flying and swimming animals provide evidence of the history of aero- and hydrodynamic force generation during the locomotor cycle. Vortex-induced momentum flux in the wake is the reaction of forces the animal imposes on its environment, which must be in equilibrium with inertial and external forces. In flying birds and bats, the flapping wings generate lift both to provide thrust and to support the weight. Distinct wingbeat and wake movement patterns can be identified as gaits. In flow visualization experiments, only two wake patterns have been identified: a vortex ring gait with inactive upstroke, and a continuous vortex gait with active upstroke. These gaits may be modelled theoretically by free vortex and lifting line theory to predict mechanical energy consumption, aerodynamic forces and muscle activity. Longer-winged birds undergo a distinct gait change with speed, but shorter-winged species use the vortex ring gait at all speeds. In swimming fish, the situation is more complex: the wake vortices form a reversed von Kármán vortex street, but little is known about the mechanism of generation of the wake, or about how it varies with speed and acceleration or with body form and swimming mode. An unresolved complicating factor is the interaction between the drag wake of the flapping fish body and the thrusting wake from the tail. PMID:8571221

  3. Water droplets also swim!

    NASA Astrophysics Data System (ADS)

    van der Linden, Marjolein; Izri, Ziane; Michelin, Sébastien; Dauchot, Olivier

    2015-03-01

    Recently there has been a surge of interest in producing artificial swimmers. One possible path is to produce self-propelling droplets in a liquid phase. The self-propulsion often relies on complex mechanisms at the droplet interface, involving chemical reactions and the adsorption-desorption kinetics of the surfactant. Here, we report the spontaneous swimming of droplets in a very simple system: water droplets immersed in an oil-surfactant medium. The swimmers consist of pure water, with no additional chemical species inside: water droplets also swim! The swimming is very robust: the droplets are able to transport cargo such as large colloids, salt crystals, and even cells. In this talk we discuss the origin of the spontaneous motion. Water from the droplet is solubilized by the reverse micellar solution, creating a concentration gradient of swollen reverse micelles around each droplet. By generalizing a recently proposed instability mechanism, we explain how spontaneous motion emerges in this system at sufficiently large Péclet number. Our water droplets in an oil-surfactant medium constitute the first experimental realization of spontaneous motion of isotropic particles driven by this instability mechanism.

  4. Swimming Eigenworms

    NASA Astrophysics Data System (ADS)

    van Bussel, Frank; Khan, Zeina; Rahman, Mizanur; Vanapalli, Siva; Blawzdziewicz, Jerzy

    2014-03-01

    The nematode C. Elegans is a much studied organism, with a fully mapped genome, cell structure, and nervous system; however, aspects of its behavior have yet to be elucidated, particularly with respect to motility under various conditions. Recently the ``Eigenworm'' technique has emerged as a promising avenue of exploration: via principle component analysis it has been shown that the state space of a healthy crawling worm is low dimensional, in that its shape can be well described by a linear combination of just four eigenmodes. So far, use of this methodology with swimming worms has been somewhat tentative, though medical research such as drug screening is commonly done with nematodes in fluid environments e.g. well plates. Here we give initial results for healthy worms swimming in liquids of varying viscosity. The main result is that at the low viscosities (M9 buffer solution) the state space is even lower dimensional than that for the crawling worm, with only two significant eigenmodes; and that as viscosity increases so does the number of modes needed for an adequate shape description. As well, the shapes of the eigenmodes undergo significant transitions across the range of viscosities looked at.

  5. Hydrodynamic interactions between laterally-spaced undulating ``fish''

    NASA Astrophysics Data System (ADS)

    Zhang, Jeany L.; Eldredge, Jeff D.

    2008-11-01

    It is generally accepted that fish achieve hydrodynamic benefits by swimming in schools, though the mechanisms used to achieve these benefits are not completely understood. In particular, the influence of lateral separation between fish has not been well characterized. In this work, it is shown that substantial increases in thrust can be obtained by fish swimming in parallel with no streamwise separation. The target of study is a two-dimensional fish-shaped profile generated about an undulating backbone. The fluid dynamics of single and multiple fish, tethered in a free-stream flow, are simulated with the viscous vortex particle method. The Reynolds number is maintained relatively low at 100. The Strouhal number of a single fish is varied to determine the value at which mean net force on the fish is zero. Then, with Strouhal number fixed, the relative distance and phase of two fish are systematically varied. It is found that the largest increase in overall thrust occurs when the fish undulate with mirror symmetry. With mirror symmetry maintained, the overall thrust decreases monotonically, but in a complex manner, as distance is increased. Systems with three fish are also studied. Finally, some preliminary results of free-swimming fish are examined.

  6. Disrupted flow sensing impairs hydrodynamic performance and increases the metabolic cost of swimming in the yellowtail kingfish, Seriola lalandi.

    PubMed

    Yanase, Kazutaka; Herbert, Neill A; Montgomery, John C

    2012-11-15

    The yellowtail kingfish, Seriola lalandi, shows a distribution of anaerobic and aerobic (red and pink) muscle fibres along the trunk that is characteristic of active pelagic fishes. The athletic capacity of S. lalandi is also shown by its relative high standard metabolic rate and optimal (i.e. least cost) swimming speed. To test the hypothesis that lateral line afferent information contributes to efficient locomotion in an active pelagic species, the swimming performance of S. lalandi was evaluated after unilateral disruption of trunk superficial neuromasts (SNs). Unilaterally disrupting the SNs of the lateral line impaired both swimming performance and energetic efficiency. The critical swimming speed (U(crit); mean ± s.d., N=12) for unilaterally SN-disrupted fish was 2.11±0.96 fork lengths (FL) s(-1), which was significantly slower than the 3.66±0.19 FL s(-1) U(crit) of sham SN-disrupted fish. The oxygen consumption rate (mg O(2) kg(-1) min(-1)) of the unilaterally SN-disrupted fish in a speed range of 1.0-2.2 FL s(-1) was significantly greater than that of the sham SN-disrupted fish. The least gross cost of transport (GCOT; N=6) for SN-disrupted fish was 0.18±0.06 J N(-1) m(-1), which was significantly greater than the 0.11±0.03 J N(-1) m(-1) GCOT for sham SN-disrupted fish. The factorial metabolic scope (N=6) of the unilaterally SN-disrupted fish (2.87±0.78) was significantly less than that of sham controls (4.14±0.37). These data show that an intact lateral line is important to the swimming performance and efficiency of carangiform swimmers, but the functional mechanism of this effect remains to be determined. PMID:22899528

  7. Thickness-varying flexible plunging fins swim more efficiently

    NASA Astrophysics Data System (ADS)

    Li, Yuanda; Yeh, Peter; Alexeev, Alexander

    2015-11-01

    We use three dimensional computer simulations to probe the hydrodynamics of oscillating flexible fins with varying thickness. The fin is modeled as an elastic rectangular plate with the thickest section at the leading edge, decreasing linearly until the trailing edge. The plate is modeled as infinitely thin, and we assume that the thickest part of the fin is much smaller compared to its other length scales. Therefore, we simulate the swimmer as two dimensional plate and introduce the effect of the thickness gradient by including an appropriate mass gradient and stiffness gradient along the length of the plate. The flexible fin is actuated by a plunging motion at its leading edge. We evaluate the performance of the swimmer by measuring the steady state thrust, free swimming velocity, input power, and swimming economy as a function of driving frequency and the magnitude of the thickness gradient. We find a wideband frequency range in which the swimming economy is increased as compared to a uniformly thick swimmer. These findings may shed insight into some of the physical mechanisms that allow fish to have high swimming efficiency.

  8. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) toxicity in fish: Mechanism and effects

    SciTech Connect

    Peterson, R.E.

    1994-12-31

    TCDD and related chemicals cause toxicity in fish by Ah receptor-mediated transcriptional induction or repression of genes involved in cell growth and regulation. Signs of acute toxicity in fish exposed as juveniles to TCDD are delayed in onset and species-specific. Mortality occurs weeks after a single dose. Fin necrosis and decreased body weight occur in many species; decreased feed consumption, hyperpigmentation, hemorrhages, edema, and altered swimming behavior occur in fewer species. Histopathological effects of TCDD are characterized by epithelial, lymphomyeloid, and cardiac lesions. The most sensitive signs of toxicity in fish exposed as juveniles occur at TCDD body burdens of 1,000 ng/kg. Early life stages of fish are the most sensitive to TCDD-induced mortality. Body burdens of TCDD which do not cause overt toxicity to adult females result in egg burdens of TCDD that decrease early life stage survival. Exposure of fertilized eggs to either waterborne, injected, or maternally transferred TCDD causes edema and death at the sac fry stage of development. Other signs of sac fry toxicity include cessation of regional blood flow, hemorrhages, exophthalmia, anemia, craniofacial malformations, and decreased growth. Lake trout sac fry are the most sensitive fish species and life stage to TCDD-induced mortality. Among Ah receptor agonists, PCDD congeners are generally the most potent in causing sac fry mortality, followed by PCDF congeners, and lastly by coplanar PCBs.

  9. Quantitative flow analysis of swimming dynamics with coherent Lagrangian vortices

    NASA Astrophysics Data System (ADS)

    Huhn, F.; van Rees, W. M.; Gazzola, M.; Rossinelli, D.; Haller, G.; Koumoutsakos, P.

    2015-08-01

    Undulatory swimmers flex their bodies to displace water, and in turn, the flow feeds back into the dynamics of the swimmer. At moderate Reynolds number, the resulting flow structures are characterized by unsteady separation and alternating vortices in the wake. We use the flow field from simulations of a two-dimensional, incompressible viscous flow of an undulatory, self-propelled swimmer and detect the coherent Lagrangian vortices in the wake to dissect the driving momentum transfer mechanisms. The detected material vortex boundary encloses a Lagrangian control volume that serves to track back the vortex fluid and record its circulation and momentum history. We consider two swimming modes: the C-start escape and steady anguilliform swimming. The backward advection of the coherent Lagrangian vortices elucidates the geometry of the vorticity field and allows for monitoring the gain and decay of circulation and momentum transfer in the flow field. For steady swimming, momentum oscillations of the fish can largely be attributed to the momentum exchange with the vortex fluid. For the C-start, an additionally defined jet fluid region turns out to balance the high momentum change of the fish during the rapid start.

  10. The development of swimming power

    PubMed Central

    Gatta, Giorgio; Leban, Bruno; Paderi, Maurizio; Padulo, Johnny; Migliaccio, Gian Mario; Pau, Massimiliano

    2014-01-01

    Summary Purpose: the aim of this study was to investigate the effects of the transfer strength training method on swimming power. Methods: twenty male swimmers “master“ were randomly allocated to strength (n= 10, ST) and swimming training (n=10, SW) groups. Both groups performed six-weeks training based on swimming training for SW and strength training which consisted in a weight training session immediately followed by the maximum swimming velocity. The performance in both groups was assessed by Maximal-Mechanical-External-Power (MMEP) before and after the six-weeks period, using a custom ergometer that provided force, velocity, and power measurement in water. Results: a significant increased MMEP in ST group (5.73% with p< 0.05) was obtained by an increased strength (11.70% with p< 0.05) and a decreased velocity (4.99% with p> 0.05). Conversely, in the SW group there was a decreased in MMEP (7.31%; p< 0.05), force and velocity (4.16%, and 3.45; respectively p> 0.05). Conclusion: this study showed that the transfer training method, based on combination of weight training (in dry condition) immediately followed by fast swim (in water) significantly improves swimming-power in master. PMID:25767781

  11. Swimming dynamics of bidirectional artificial flagella.

    PubMed

    Namdeo, S; Khaderi, S N; Onck, P R

    2013-10-01

    We study magnetic artificial flagella whose swimming speed and direction can be controlled using light and magnetic field as external triggers. The dependence of the swimming velocity on the system parameters (e.g., length, stiffness, fluid viscosity, and magnetic field) is explored using a computational framework in which the magnetostatic, fluid dynamic, and solid mechanics equations are solved simultaneously. A dimensionless analysis is carried out to obtain an optimal combination of system parameters for which the swimming velocity is maximal. The swimming direction reversal is addressed by incorporating photoresponsive materials, which in the photoactuated state can mimic natural mastigonemes. PMID:24229282

  12. Mechanism of synergistic action following co-treatment with pramipexole and fluoxetine or sertraline in the forced swimming test in rats.

    PubMed

    Rogóz, Zofia; Skuza, Grazyna

    2006-01-01

    The aim of the present study was to examine the effect of combined treatment of male Wistar rats with pramipexole and fluoxetine or sertraline in the forced swimming test. The obtained results showed that co-treatment with pramipexole (0.1 mg/kg) and fluoxetine (10 mg/kg) or sertraline (5 mg/kg) (in doses inactive per se) exhibited antidepressant-like activity in the forced swimming test. Sulpiride (a dopamine D(2/3) receptor antagonist) and WAY 100635 (a 5-HT(1A) receptor antagonist), either being ineffective in the forced swimming test, inhibited the antidepressant-like effect induced by co-administration of pramipexole and fluoxetine or sertraline. However, SCH 23390 (a dopamine D(1) receptor antagonist) only partly did not alter the effect of pramipexole given jointly with antidepressant drugs; on the other hand, S 33084 (a dopamine D(3) receptor antagonist) only partly decreased (in a statistically insignificant manner) that effect. Moreover, progesterone and BD 1047 (a sigma(1) receptor antagonist) counteracted the antidepressant-like effect induced by co-administration of pramipexole and sertraline (but not pramipexole and fluoxetine). In that test, active behavior did not reflect the increases in general activity, since combined administration of pramipexole and fluoxetine or sertraline failed to enhance the locomotor activity of rats. None of the tested drugs (SCH 23390, sulpiride, S 33084, WAY 100635, BD 1047 and progesterone) - alone or in combination with pramipexole and fluoxetine or sertraline - changed locomotor activity. The results described in the present paper indicate that co-administration of pramipexole and fluoxetine or sertraline may induce a more pronounced antidepressive activity than does treatment with pramipexole alone, and that in addition to other mechanisms, dopamine D(2/3) and 5-HT(1A) receptors may contribute to the antidepressant-like activity of pramipexole and fluoxetine or sertraline in the forced swimming test in rats

  13. Behavioural relevance of polarization sensitivity as a target detection mechanism in cephalopods and fishes

    PubMed Central

    Pignatelli, Vincenzo; Temple, Shelby E.; Chiou, Tsyr-Huei; Roberts, Nicholas W.; Collin, Shaun P.; Marshall, N. Justin

    2011-01-01

    Aquatic habitats are rich in polarized patterns that could provide valuable information about the environment to an animal with a visual system sensitive to polarization of light. Both cephalopods and fishes have been shown to behaviourally respond to polarized light cues, suggesting that polarization sensitivity (PS) may play a role in improving target detection and/or navigation/orientation. However, while there is general agreement concerning the presence of PS in cephalopods and some fish species, its functional significance remains uncertain. Testing the role of PS in predator or prey detection seems an excellent paradigm with which to study the contribution of PS to the sensory assets of both groups, because such behaviours are critical to survival. We developed a novel experimental set-up to deliver computer-generated, controllable, polarized stimuli to free-swimming cephalopods and fishes with which we tested the behavioural relevance of PS using stimuli that evoke innate responses (such as an escape response from a looming stimulus and a pursuing behaviour of a small prey-like stimulus). We report consistent responses of cephalopods to looming stimuli presented in polarization and luminance contrast; however, none of the fishes tested responded to either the looming or the prey-like stimuli when presented in polarization contrast. PMID:21282177

  14. Iron Uptake Mechanisms in the Fish Pathogen Tenacibaculum maritimum

    PubMed Central

    Avendaño-Herrera, Ruben; Toranzo, Alicia E.; Romalde, Jesús L.; Lemos, Manuel L.; Magariños, Beatriz

    2005-01-01

    We present here the first evidence of the presence of iron uptake mechanisms in the bacterial fish pathogen Tenacibaculum maritimum. Representative strains of this species, with different serotypes and origins, were examined. All of them were able to grow in the presence of the chelating agent ethylenediamine-di- (o-hydroxyphenyl acetic acid) (EDDHA) and also produced siderophores. Cross-feeding assays suggest that the siderophores produced are closely related. In addition, all T. maritimum strains utilized transferrin, hemin, hemoglobin, and ferric ammonic citrate as iron sources when added to iron-deficient media. Whole cells of all T. maritimum strains, grown under iron-supplemented or iron-restricted conditions, were able to bind hemin, indicating the existence of constitutive binding components located at the T. maritimum cell surface. This was confirmed by the observation that isolated total and outer membrane proteins from all of the strains, regardless of the iron levels of the media, were able to bind hemin, with the outer membranes showing the strongest binding. proteinase K treatment of whole cells did not affect the hemin binding, indicating that, in addition to proteins, some protease-resistant components could also bind hemin. At least three outer membrane proteins were induced in iron-limiting conditions, and all strains, regardless of their serotype, showed a similar pattern of induced proteins. The results of the present study suggest that T. maritimum possesses at least two different systems of iron acquisition: one involving the synthesis of siderophores and another that allows the utilization of heme groups as iron sources by direct binding. PMID:16269729

  15. Iron uptake mechanisms in the fish pathogen Tenacibaculum maritimum.

    PubMed

    Avendaño-Herrera, Ruben; Toranzo, Alicia E; Romalde, Jesús L; Lemos, Manuel L; Magariños, Beatriz

    2005-11-01

    We present here the first evidence of the presence of iron uptake mechanisms in the bacterial fish pathogen Tenacibaculum maritimum. Representative strains of this species, with different serotypes and origins, were examined. All of them were able to grow in the presence of the chelating agent ethylenediamine-di-(o-hydroxyphenyl acetic acid) (EDDHA) and also produced siderophores. Cross-feeding assays suggest that the siderophores produced are closely related. In addition, all T. maritimum strains utilized transferrin, hemin, hemoglobin, and ferric ammonic citrate as iron sources when added to iron-deficient media. Whole cells of all T. maritimum strains, grown under iron-supplemented or iron-restricted conditions, were able to bind hemin, indicating the existence of constitutive binding components located at the T. maritimum cell surface. This was confirmed by the observation that isolated total and outer membrane proteins from all of the strains, regardless of the iron levels of the media, were able to bind hemin, with the outer membranes showing the strongest binding. Proteinase K treatment of whole cells did not affect the hemin binding, indicating that, in addition to proteins, some protease-resistant components could also bind hemin. At least three outer membrane proteins were induced in iron-limiting conditions, and all strains, regardless of their serotype, showed a similar pattern of induced proteins. The results of the present study suggest that T. maritimum possesses at least two different systems of iron acquisition: one involving the synthesis of siderophores and another that allows the utilization of heme groups as iron sources by direct binding. PMID:16269729

  16. Swimming impairment and acetylcholinesterase inhibition in zebrafish exposed to copper or chlorpyrifos separately, or as mixtures

    PubMed Central

    Tilton, Fred A.; Bammler, Theo K.; Gallagher, Evan P.

    2010-01-01

    Pesticides such as chlorpyrifos (CPF) and metals such as copper can impair swimming behavior in fish. However, the impact to swimming behavior from exposure to mixtures of neurotoxicants has received little attention. In the current study, we analyzed spontaneous swimming rates of adult zebrafish (Danio rerio) to investigate in vivo mixture interactions involving two chemical classes. Zebrafish were exposed to the neurotoxicants copper chloride (CuCl, 0.1 μM, 0.25 μM, 0.6 μM, or 6.3, 16, 40 ppb), chlorpyrifos (CPF, 0.1 μM, 0.25 μM, 0.6 μM, or 35, 88, 220 ppb) and binary mixtures for 24 hr to better understand the effects of Cu on CPF neurotoxicity. Exposure to CPF increased the number of animals undergoing freeze responses (an anti-predator behavior) and, at the highest CPF dose (0.6 μM), elicited a decrease in zebrafish swimming rates. Interestingly, the addition of Cu caused a reduction in the number of zebrafish in the CPF-exposure groups undergoing freeze responses. There was no evidence of additive or synergistic toxicity between Cu and CPF. Although muscle AChE activity was significantly reduced by CPF, there was a relatively poor relationship among muscle AChE concentrations and swimming behavior, suggesting non-muscle AChE mechanisms in the loss of swimming behavior. In summary, we have observed a modulating effect of Cu on CPF swimming impairment that appears to involve both AChE and non-AChE mechanisms. Our study supports the utility of zebrafish in understanding chemical mixture interactions and neurobehavioral injury. PMID:20692364

  17. Gelation, oxygen permeability and mechanical properties of mammalian and fish gelatin films

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to evaluate the gelation, thermal, mechanical and oxygen permeability properties of different mammalian, warm- and cold-water fish gelatin solutions and films. Mammalian gelatin solutions had the highest gel set temperatures, followed by warm-water fish and then cold-...

  18. 40 CFR 408.220 - Applicability; description of the non-Alaskan mechanized bottom fish processing subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-Alaskan mechanized bottom fish processing subcategory. 408.220 Section 408.220 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Alaskan Mechanized Bottom Fish Processing Subcategory § 408.220 Applicability; description of the non-Alaskan mechanized bottom fish processing subcategory. The provisions...

  19. 40 CFR 408.220 - Applicability; description of the non-Alaskan mechanized bottom fish processing subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-Alaskan mechanized bottom fish processing subcategory. 408.220 Section 408.220 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Alaskan Mechanized Bottom Fish Processing Subcategory § 408.220 Applicability; description of the non-Alaskan mechanized bottom fish processing subcategory. The provisions...

  20. 40 CFR 408.220 - Applicability; description of the non-Alaskan mechanized bottom fish processing subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-Alaskan mechanized bottom fish processing subcategory. 408.220 Section 408.220 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Alaskan Mechanized Bottom Fish Processing Subcategory § 408.220 Applicability; description of the non-Alaskan mechanized bottom fish processing subcategory. The provisions...

  1. 40 CFR 408.220 - Applicability; description of the non-Alaskan mechanized bottom fish processing subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-Alaskan mechanized bottom fish processing subcategory. 408.220 Section 408.220 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Alaskan Mechanized Bottom Fish Processing Subcategory § 408.220 Applicability; description of the non-Alaskan mechanized bottom fish processing subcategory. The provisions...

  2. 40 CFR 408.220 - Applicability; description of the non-Alaskan mechanized bottom fish processing subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-Alaskan mechanized bottom fish processing subcategory. 408.220 Section 408.220 Protection of Environment... PROCESSING POINT SOURCE CATEGORY Non-Alaskan Mechanized Bottom Fish Processing Subcategory § 408.220 Applicability; description of the non-Alaskan mechanized bottom fish processing subcategory. The provisions...

  3. No evidence for a bioenergetic advantage from forced swimming in rainbow trout under a restrictive feeding regime.

    PubMed

    Skov, Peter V; Lund, Ivar; Pargana, Alexandre M

    2015-01-01

    Sustained swimming at moderate speeds is considered beneficial in terms of the productive performance of salmonids, but the causative mechanisms have yet to be unequivocally established. In the present study, the effects of moderate exercise on the bioenergetics of rainbow trout were assessed during a 15 week growth experiment, in which fish were reared at three different current speeds: 1 BL s(-1), 0.5 BL s(-1) and still water (≈ 0 BL s(-1)). Randomly selected groups of 100 fish were distributed among twelve 600 L tanks and maintained on a restricted diet regime. Specific growth rate (SGR) and feed conversion ratio (FCR) were calculated from weight and length measurements every 3 weeks. Routine metabolic rate (RMR) was measured every hour as rate of oxygen consumption in the tanks, and was positively correlated with swimming speed. Total ammonia nitrogen (TAN) excretion rates showed a tendency to decrease with increasing swimming speeds, yet neither they nor the resulting nitrogen quotients (NQ) indicated that swimming significantly reduced the fraction of dietary protein used to fuel metabolism. Energetic budgets revealed a positive correlation between energy expenditure and the current speed at which fish were reared, fish that were forced to swim and were fed restrictively consequentially had poorer growth and feed utilization. The results show that for rainbow trout, water current can negatively affect growth despite promoting minor positive changes in substrate utilization. We hypothesize that this may be the result of either a limited dietary energy supply from diet restriction being insufficient for both covering the extra costs of swimming and supporting enhanced growth. PMID:25705195

  4. No evidence for a bioenergetic advantage from forced swimming in rainbow trout under a restrictive feeding regime

    PubMed Central

    Skov, Peter V.; Lund, Ivar; Pargana, Alexandre M.

    2015-01-01

    Sustained swimming at moderate speeds is considered beneficial in terms of the productive performance of salmonids, but the causative mechanisms have yet to be unequivocally established. In the present study, the effects of moderate exercise on the bioenergetics of rainbow trout were assessed during a 15 week growth experiment, in which fish were reared at three different current speeds: 1 BL s−1, 0.5 BL s−1 and still water (≈ 0 BL s−1). Randomly selected groups of 100 fish were distributed among twelve 600 L tanks and maintained on a restricted diet regime. Specific growth rate (SGR) and feed conversion ratio (FCR) were calculated from weight and length measurements every 3 weeks. Routine metabolic rate (RMR) was measured every hour as rate of oxygen consumption in the tanks, and was positively correlated with swimming speed. Total ammonia nitrogen (TAN) excretion rates showed a tendency to decrease with increasing swimming speeds, yet neither they nor the resulting nitrogen quotients (NQ) indicated that swimming significantly reduced the fraction of dietary protein used to fuel metabolism. Energetic budgets revealed a positive correlation between energy expenditure and the current speed at which fish were reared, fish that were forced to swim and were fed restrictively consequentially had poorer growth and feed utilization. The results show that for rainbow trout, water current can negatively affect growth despite promoting minor positive changes in substrate utilization. We hypothesize that this may be the result of either a limited dietary energy supply from diet restriction being insufficient for both covering the extra costs of swimming and supporting enhanced growth. PMID:25705195

  5. Analyzing the fast-start performance of northern pike using a mechanical fish

    NASA Astrophysics Data System (ADS)

    Modarres-Sadeghi, Yahya; Feng, Chengcheng; Bonafilia, Brian; Costain, Andrew

    2011-11-01

    The northern pike is able to achieve an instantaneous acceleration of 245 m/s2 through a two-stage motion. In the first stage the fish curls its body into either a C-shaped or an S-shaped curve (preparatory stage), and in the second stage uncurls it very quickly (propulsive stage) generating high accelerations due to the vortices shed from its tail. We have built a mechanical fish, based on the body profile of a pike, which is capable of performing this two-stage fast-start motion. Movement is governed by servo motors, which pull on cables attached to certain ribs, bending the fish into a C- or an S-shape. The degree of bending and timing of strokes can be controlled, and the fish can perform either a propulsive stroke only or a full stroke consisting of both the preparatory stage and the propulsive stage. The mechanical fish is capable of achieving peak accelerations of around 4 m/s2. We use this fish in order to study the influence of various variables on the observed acceleration. Although the maximum accelerations observed in our mechanical fish are smaller than those of a live fish, the form of the measured acceleration signal as function of time is quite similar to that of a live fish. The hydrodynamic efficiencies are observed to be around 12%, and it is shown that the majority of the thrust is produced at the rear part of the mechanical fish--similarly to the live fish.

  6. Swimming pool cleaner poisoning

    MedlinePlus

    Swimming pool cleaner poisoning occurs when someone swallows this type of cleaner, touches it, or breathes in ... The harmful substances in swimming pool cleaner are: Bromine ... copper Chlorine Soda ash Sodium bicarbonate Various mild acids

  7. Swimming pool granuloma

    MedlinePlus

    A swimming pool granuloma is a long-term (chronic) skin infection. It is caused by the bacteria Mycobacterium marinum . ... A swimming pool granuloma occurs when water containing Mycobacterium marinum bacteria enters a break in the skin. Signs of ...

  8. Feeding and swimming of flagellates

    NASA Astrophysics Data System (ADS)

    Doelger, Julia; Nielsen, Lasse Tor; Kiorboe, Thomas; Bohr, Tomas; Andersen, Anders

    2015-11-01

    Hydrodynamics plays a dominant role for small planktonic flagellates and shapes their survival strategies. The high diversity of beat patterns and arrangements of appendages indicates different strategies balancing the trade-offs between the general goals, i.e., energy-efficient swimming, feeding, and predator avoidance. One type of flagellated algae that we observe, are haptophytes, which possess two flagella for flow creation and one so-called haptonema, a long, rigid structure fixed on the cell body, which is used for prey capture. We present videos and flow fields obtained using velocimetry methods around freely swimming haptophytes and other flagellates, which we compare to analytical results obtained from point force models. The observed and modelled flows are used to analyse how different morphologies and beat patterns relate to different feeding or swimming strategies, such as the capture mechanism in haptophytes. The Centre for Ocean Life is a VKR center of excellence supported by the Villum foundation.

  9. Compensatory mechanisms in fish populations: Literature reviews: Volume 2, Compensation in fish populations subject to catastrophic impact: Final report

    SciTech Connect

    Jude, D.J.; Mansfield, P.J.; Schneeberger, P.J.; Wojcik, J.A.

    1987-05-01

    This study comprises an extensive literature review, critical evaluations of case histories, and considered recommendations for future research on the mechanisms and extent of compensation by various fish species subject to catastrophic impacts. ''Catastrophic impact'' was defined as an event which removes some limitation (such as food or space) on a fish population. Those events studied included new species introduction, toxic spills, exploitation of specific fish populations, and drawdown. The fish studied each had more than one compensatory mechanism available, and thus were able to respond to a catastrophic event even if an option was removed. Predation, overfishing, competition, disease, and parasitism are all potential catastrophies, but were found not to cause a catastrophic impact (except in special cases). In general, compensatory responses were determined to vary widely, even for species which perform fairly similar functions in an ecosystem. The extensive nature of this study, however, pointed up the many data gaps in the existing literature; recommendations are therefore made for followup research and expansion of ongoing monitoring programs, based on an evaluation of their relative importance.

  10. Mechanisms of zinc toxicity in the galaxiid fish, Galaxias maculatus.

    PubMed

    McRae, Nicole K; Gaw, Sally; Glover, Chris N

    2016-01-01

    Zinc (Zn) is an essential metal, which is ubiquitous in aquatic environments occurring both naturally, and through anthropogenic inputs. This study investigated impacts of sub-lethal Zn exposure in the galaxiid fish Galaxias maculatus. Known as inanga, this amphidromous fish is widespread throughout the Southern hemisphere, but to date almost nothing is known regarding its sensitivity to elevated environmental metals. Fish were exposed to environmentally-relevant concentrations of Zn (control, 8, 270 and 1000μgL(-1)) over 96h. End-points measured included those relating to ionoregulatory disturbance (whole body calcium and sodium influx), oxygen consumption (respirometry), oxidative stress (catalase activity and lipid peroxidation) and whole body accumulation of Zn. Zn exposure caused increases in catalase activity and lipid peroxidation, but only at the highest exposure level tested. Zn also significantly inhibited calcium influx, but stimulated sodium influx, at 1000μgL(-1). The sub-lethal changes induced by Zn exposure in inanga appear to be conserved relative to other, better-studied species. These data are the first to explore the sensitivity of juvenile galaxiid fish to Zn, information that will be critical to ensuring adequate environmental protection of this important species. PMID:26510681

  11. The swim force as a body force

    NASA Astrophysics Data System (ADS)

    Yan, Wen; Brady, John

    2015-11-01

    Net (as opposed to random) motion of active matter results from an average swim (or propulsive) force. It is shown that the average swim force acts like a body force - an internal body force [Yan and Brady, Soft Matter, DOI:10.1039/C5SM01318F]. As a result, the particle-pressure exerted on a container wall is the sum of the swim pressure [Takatori et al., Phys. Rev. Lett., 2014, 113, 028103] and the `weight' of the active particles. A continuum mechanical description is possible when variations occur on scales larger than the run length of the active particles and gives a Boltzmann-like distribution from a balance of the swim force and the swim pressure. Active particles may also display `action at a distance' and accumulate adjacent to (or be depleted from) a boundary without any external forces. In the momentum balance for the suspension - the mixture of active particles plus fluid - only external body forces appear.

  12. Effects of feeding on the sustained swimming abilities of late-stage larval Amphiprion melanopus

    NASA Astrophysics Data System (ADS)

    Fisher, R.; Bellwood, D.

    2001-09-01

    To date, all sustained swimming experiments on tropical reef fish larvae have been conducted using unfed larvae. Such studies may produce unrealistic estimates of sustained swimming abilities. We examined the effect of food on the sustained swimming ability of late-stage Amphiprion melanopus. Larvae were swum in a six-channel swimming flume at 7 cm s-1, with "unfed" and "fed" channels. Fed channels had Artemia nauplii added four times per day for 10 min. Feeding larvae during swimming experiments significantly increased their average swimming distance from around 6.9 to 12.2 km, and the maximum swimming distance from around 11.8 to 28.7 km. Existing flume-based estimates of sustained swimming may be underestimating field abilities. With access to food, many larvae may have the potential to swim considerably greater distances than previously suggested.

  13. Shape Optimization of Swimming Sheets

    SciTech Connect

    Wilkening, J.; Hosoi, A.E.

    2005-03-01

    The swimming behavior of a flexible sheet which moves by propagating deformation waves along its body was first studied by G. I. Taylor in 1951. In addition to being of theoretical interest, this problem serves as a useful model of the locomotion of gastropods and various micro-organisms. Although the mechanics of swimming via wave propagation has been studied extensively, relatively little work has been done to define or describe optimal swimming by this mechanism.We carry out this objective for a sheet that is separated from a rigid substrate by a thin film of viscous Newtonian fluid. Using a lubrication approximation to model the dynamics, we derive the relevant Euler-Lagrange equations to optimize swimming speed and efficiency. The optimization equations are solved numerically using two different schemes: a limited memory BFGS method that uses cubic splines to represent the wave profile, and a multi-shooting Runge-Kutta approach that uses the Levenberg-Marquardt method to vary the parameters of the equations until the constraints are satisfied. The former approach is less efficient but generalizes nicely to the non-lubrication setting. For each optimization problem we obtain a one parameter family of solutions that becomes singular in a self-similar fashion as the parameter approaches a critical value. We explore the validity of the lubrication approximation near this singular limit by monitoring higher order corrections to the zeroth order theory and by comparing the results with finite element solutions of the full Stokes equations.

  14. Limit cycle dynamics in swimming systems

    NASA Astrophysics Data System (ADS)

    Finkel, Cyndee; von Ellenrieder, Karl

    2013-11-01

    An experimental apparatus was constructed to model basic features expected in the flow about a freely swimming fish. A D-shaped cylinder is used to represent the body and an oscillating foil, the tail. The swimming system is suspended in a constant freestream flow. A closed loop PI controller is used to maintain a set point, stream-wise location. The system is released from multiple downstream and upstream locations and permitted to swim to the set point. The Strouhal number measured when the swimming system achieves a constant forward swimming speed is compared to values observed in nature. The results suggest that self-regulation passively selects the Strouhal number and that no other external sensory input is necessary for this to happen. This self-regulation is a result of a limit cycle process that stems from nonlinear periodic oscillations. Phase plane analyses are used to examine the synchronous conditions due to the coupling of the foil and wake vortices. It is shown that the phase locking indices depend on the Strouhal number and approach a frequency locking ratio of about 0 . 5 . The results suggest that Strouhal number selection in steady forward natural swimming is the result of a limit cycle process and not actively controlled by an organism.

  15. Energetics of median and paired fin swimming, body and caudal fin swimming, and gait transition in parrotfish (Scarus schlegeli) and triggerfish (Rhinecanthus aculeatus).

    PubMed

    Korsmeyer, Keith E; Steffensen, John Fleng; Herskin, Jannik

    2002-05-01

    To determine the energetic costs of rigid-body, median or paired-fin (MPF) swimming versus undulatory, body-caudal fin (BCF) swimming, we measured oxygen consumption as a function of swimming speed in two MPF swimming specialists, Schlegel's parrotfish and Picasso triggerfish. The parrotfish swam exclusively with the pectoral fins at prolonged swimming speeds up to 3.2 total lengths per second (L s(-1); 30 min critical swimming speed, U(crit)). At higher speeds, gait transferred to a burst-and-coast BCF swimming mode that resulted in rapid fatigue. The triggerfish swam using undulations of the soft dorsal and anal fins up to 1.5 L s(-1), beyond which BCF undulations were recruited intermittently. BCF swimming was used continuously above 3.5 L s(-1), and was accompanied by synchronous undulations of the dorsal and anal fins. The triggerfish were capable of high, prolonged swimming speeds of up to 4.1 L s(-1) (30 min U(crit)). In both species, the rates of increase in oxygen consumption with swimming speed were higher during BCF swimming than during rigid-body MPF swimming. Our results indicate that, for these species, undulatory swimming is energetically more costly than rigid-body swimming, and therefore support the hypothesis that MPF swimming is more efficient. In addition, use of the BCF gait at higher swimming speed increased the cost of transport in both species beyond that predicted for MPF swimming at the same speeds. This suggests that, unlike for terrestrial locomotion, gait transition in fishes does not occur to reduce energetic costs, but to increase recruitable muscle mass and propulsive surfaces. The appropriate use of the power and exponential functions to model swimming energetics is also discussed. PMID:11948202

  16. The physics of swimming

    NASA Astrophysics Data System (ADS)

    Kent, M. R.

    1980-09-01

    Like all physical skills swimming is subject to the laws of mechanics. Until fairly recently, however, the biomechanical study of this cross disciplinary activity has been largely left alone by the two specialists who would be primarily involved, the physicist and the physical educationist. Since the early 1970s, however, a greater cross fertilisation of ideas has taken place and the sports scientist has emerged. It is possible to analyse human performance and thus identify areas where for example greater strength, a slightly different angle or a slightly different degree of twist might produce that all important extra few millimetres in distance or that reduction in time of a few milliseconds. In man's search for excellence this is important. The study of the performance of a sprinting swimmer in biomechanical terms makes it possible to build up a model of the stroke under investigation which may then be improved upon.

  17. Swimming bacteria in liquid crystal

    NASA Astrophysics Data System (ADS)

    Sokolov, Andrey; Zhou, Shuang; Aranson, Igor; Lavrentovich, Oleg

    2014-03-01

    Dynamics of swimming bacteria can be very complex due to the interaction between the bacteria and the fluid, especially when the suspending fluid is non-Newtonian. Placement of swimming bacteria in lyotropic liquid crystal produces a new class of active materials by combining features of two seemingly incompatible constituents: self-propelled live bacteria and ordered liquid crystals. Here we present fundamentally new phenomena caused by the coupling between direction of bacterial swimming, bacteria-triggered flows and director orientations. Locomotion of bacteria may locally reduce the degree of order in liquid crystal or even trigger nematic-isotropic phase transition. Microscopic flows generated by bacterial flagella disturb director orientation. Emerged birefringence patterns allow direct optical observation and quantitative characterization of flagella dynamics. At high concentration of bacteria we observed the emergence of self-organized periodic texture caused by bacteria swimming. Our work sheds new light on self-organization in hybrid bio-mechanical systems and can lead to valuable biomedical applications. Was supported by the US DOE, Office of Basic Energy Sciences, Division of Materials Science and Engineering, under the Contract No. DE AC02-06CH11357.

  18. Upward swimming of a sperm cell in shear flow.

    PubMed

    Omori, Toshihiro; Ishikawa, Takuji

    2016-03-01

    Mammalian sperm cells are required to swim over long distances, typically around 1000-fold their own length. They must orient themselves and maintain a swimming motion to reach the ovum, or egg cell. Although the mechanism of long-distance navigation is still unclear, one possible mechanism, rheotaxis, was reported recently. This work investigates the mechanism of the rheotaxis in detail by simulating the motions of a sperm cell in shear flow adjacent to a flat surface. A phase diagram was developed to show the sperm's swimming motion under different shear rates, and for varying flagellum waveform conditions. The results showed that, under shear flow, the sperm is able to hydrodynamically change its swimming direction, allowing it to swim upwards against the flow, which suggests that the upward swimming of sperm cells can be explained using fluid mechanics, and this can then be used to further understand physiology of sperm cell navigation. PMID:27078385

  19. Upward swimming of a sperm cell in shear flow

    NASA Astrophysics Data System (ADS)

    Omori, Toshihiro; Ishikawa, Takuji

    2016-03-01

    Mammalian sperm cells are required to swim over long distances, typically around 1000-fold their own length. They must orient themselves and maintain a swimming motion to reach the ovum, or egg cell. Although the mechanism of long-distance navigation is still unclear, one possible mechanism, rheotaxis, was reported recently. This work investigates the mechanism of the rheotaxis in detail by simulating the motions of a sperm cell in shear flow adjacent to a flat surface. A phase diagram was developed to show the sperm's swimming motion under different shear rates, and for varying flagellum waveform conditions. The results showed that, under shear flow, the sperm is able to hydrodynamically change its swimming direction, allowing it to swim upwards against the flow, which suggests that the upward swimming of sperm cells can be explained using fluid mechanics, and this can then be used to further understand physiology of sperm cell navigation.

  20. Swimming Orientation for Preschoolers.

    ERIC Educational Resources Information Center

    Smith, Mary Lou

    1990-01-01

    Techniques which are designed to dispel fears and promote confident learning are offered to preschool swimming instructors. Safety, class organization, water games, and class activities are discussed. (IAH)

  1. Evaluation of fish-injury mechanisms during exposure to a high-velocity jet

    SciTech Connect

    Guensch, Gregory R.; Mueller, Robert P.; McKinstry, Craig A.; Dauble, Dennis D.

    2002-11-01

    As part of the research supported by U.S. Department of Energy (DOE) Advanced Hydropower Turbine System (AHTS) Program, the Pacific Northwest National Laboratory (PNNL) conducted a study where age-0 and age-1 Chinook salmon, as well as several other types of fish, were released into a submerged water jet to quantify injuries caused by shear stresses and turbulence (Neitzel et al. 2000). The fish releases were videotaped. These videotape records were digitized and analyzed using new methods to identify the injury mechanisms and the stresses involved. Visible external injuries sustained by fish in this study generally occurred during the initial contact with the jet and not during the tumbling that occurred after the fish fully entered the turbulent flow. The inertial stresses of tumbling, however, may cause temporary or even permanent vestibular and neurological injuries. Such injuries can result in disorientation and loss of equilibrium, which are life threatening in the “natural” environment. Operculum injuries predominated at moderate water jet speeds (12 and 15 m/s). At the highest speed, eye, operculum, isthmus, and gill injuries were equally common, and disorientation was most common. Bruising and descaling were relatively rare, especially for age-0 fish. Age-0 fish were less susceptible than the larger age-1 fish to all visible injury types, especially at lower speeds.

  2. New insights into the mechanism of lens development using zebra fish.

    PubMed

    Greiling, Teri M S; Clark, John I

    2012-01-01

    On the basis of recent advances in molecular biology, genetics, and live-embryo imaging, direct comparisons between zebra fish and human lens development are being made. The zebra fish has numerous experimental advantages for investigation of fundamental biomedical problems that are often best studied in the lens. The physical characteristics of visible light can account for the highly coordinated cell differentiation during formation of a beautifully transparent, refractile, symmetric optical element, the biological lens. The accessibility of the zebra fish lens for direct investigation during rapid development will result in new knowledge about basic functional mechanisms of epithelia-mesenchymal transitions, cell fate, cell-matrix interactions, cytoskeletal interactions, cytoplasmic crowding, membrane transport, cell adhesion, cell signaling, and metabolic specialization. The lens is well known as a model for characterization of cell and molecular aging. We review the recent advances in understanding vertebrate lens development conducted with zebra fish. PMID:22559937

  3. Mechanisms driving recruitment variability in fish: comparisons between the Laurentian Great Lakes and marine systems

    USGS Publications Warehouse

    Pritt, Jeremy J.; Roseman, Edward F.; O'Brien, Timothy P.

    2014-01-01

    In his seminal work, Hjort (in Fluctuations in the great fisheries of Northern Europe. Conseil Parmanent International Pour L'Exploration De La Mar. Rapports et Proces-Verbaux, 20: 1–228, 1914) observed that fish population levels fluctuated widely, year-class strength was set early in life, and egg production by adults could not alone explain variability in year-class strength. These observations laid the foundation for hypotheses on mechanisms driving recruitment variability in marine systems. More recently, researchers have sought to explain year-class strength of important fish in the Laurentian Great Lakes and some of the hypotheses developed for marine fisheries have been transferred to Great Lakes fish. We conducted a literature review to determine the applicability of marine recruitment hypotheses to Great Lakes fish. We found that temperature, interspecific interactions, and spawner effects (abundance, age, and condition of adults) were the most important factors in explaining recruitment variability in Great Lakes fish, whereas relatively fewer studies identified bottom-up trophodynamic factors or hydrodynamic factors as important. Next, we compared recruitment between Great Lakes and Baltic Sea fish populations and found no statistical difference in factors driving recruitment between the two systems, indicating that recruitment hypotheses may often be transferable between Great Lakes and marine systems. Many recruitment hypotheses developed for marine fish have yet to be applied to Great Lakes fish. We suggest that future research on recruitment in the Great Lakes should focus on forecasting the effects of climate change and invasive species. Further, because the Great Lakes are smaller and more enclosed than marine systems, and have abundant fishery-independent data, they are excellent candidates for future hypothesis testing on recruitment in fish.

  4. Volumetric flow around a swimming lamprey

    NASA Astrophysics Data System (ADS)

    Lehn, Andrea M.; Colin, Sean P.; Costello, John H.; Leftwich, Megan C.; Tytell, Eric D.

    2015-11-01

    A primary experimental technique for studying fluid-structure interactions around swimming fish has been planar dimensional particle image velocimetry (PIV). Typically, two components of the velocity vector are measured in a plane, in the case of swimming studies, directly behind the animal. While useful, this approach provides little to no insight about fluid structure interactions above and below the fish. For fish with a small height relative to body length, such as the long and approximately cylindrical lamprey, 3D information is essential to characterize how these fish interact with their fluid environment. This study presents 3D flow structures along the body and in the wake of larval lamprey, P etromyzon m arinus , which are 10-15 cm long. Lamprey swim through a 1000 cm3 field of view in a standard 10 gallon tank illuminated by a green laser. Data are collected using the three component velocimeter V3V system by TSI, Inc. and processed using Insight 4G software. This study expands on previous works that show two pairs of vortices each tail beat in the mid-plane of the lamprey wake. NSF DMS 1062052.

  5. Centropages behaviour: Swimming and vertical migration

    NASA Astrophysics Data System (ADS)

    Alcaraz, Miguel; Saiz, Enric; Calbet, Albert

    2007-02-01

    The evolutionary success of any species living in a variable environment depends on its capacity to enhance the probability of finding food and mates, and escaping predators. In the case of copepods of the genus Centropages, as in all planktonic copepods, their swimming behaviour is closely tied to these vital aspects, and shows a high degree of plasticity and adaptive capacity. Swimming mechanisms of Centropages change radically during development, mainly in the transition between naupliar stages to the 1st copepodite; nauplii do not produce feeding currents, whereas copepodites do. Adults and late developmental stages of C. typicus, C. hamatus and C. velificatus spend most of the time in slow swimming and resting breaks, with occasional and brief fast swimming (escape reactions) and grooming events. Slow swimming is closely related to the creation of feeding currents, and results from the beating of the cephalic appendages in a “fling and clap” manner. The proportion of time allocated to the different swimming activities depends on sensory cues like type and concentration of food, presence of potential mates, light intensity, hydrodynamic flow, etc. The responses of Centropages to changes in flow velocity fluctuations (small-scale turbulence) are similar to the escape responses (fast swimming) triggered by the presence of potential predators. Centropages generally have standard nocturnal vertical migration patterns involving considerable vertical displacements. This behaviour is closely related to the narrow spectral sensitivity and the low intensity threshold of the genus, and has important consequences for the active vertical transport of matter and energy. The variety of responses of Centropages to environmental changes, and in general all the aspects related to its swimming behaviour seem to be controlled by the trade-off between energetic gains (food intake), losses (swimming energy expenditure), and predation risk. Behavioural plasticity and adaptation

  6. Teaching Swimming Effectively.

    ERIC Educational Resources Information Center

    Larrabee, Jean G.

    A step-by-step sequential plan is offered for developing a successful competitive swimming season, including how to teach swimming strokes and organize practices. Various strokes are analyzed, and coaching check points are offered along with practice drills, helpful hints on proper body positioning, arm strokes, kicking patterns, breathing…

  7. CASTING A BROAD NETWORK: FISHING FOR MECHANISMS OF RETINOID TERATOGENICITY

    EPA Science Inventory

    This is a short essay that serves to introduce a featured paper for an issue of Toxicological Sciences. The paper being introduced describes a study of mechanisms of retinoid induced abnormal limb development in mice. The paper was notable because the authors used gene expressi...

  8. Sustained swimming increases the mineral content and osteocyte density of salmon vertebral bone

    PubMed Central

    Totland, Geir K; Fjelldal, Per Gunnar; Kryvi, Harald; Løkka, Guro; Wargelius, Anna; Sagstad, Anita; Hansen, Tom; Grotmol, Sindre

    2011-01-01

    This study addresses the effects of increased mechanical load on the vertebral bone of post-smolt Atlantic salmon by forcing them to swim at controlled speeds. The fish swam continuously in four circular tanks for 9 weeks, two groups at 0.47 body lengths (bl) × s−1 (non-exercised group) and two groups at 2 bl × s−1 (exercised group), which is just below the limit for maximum sustained swimming speed in this species. Qualitative data concerning the vertebral structure were obtained from histology and electron microscopy, and quantitative data were based on histomorphometry, high-resolution X-ray micro-computed tomography images and analysis of bone mineral content, while the mechanical properties were tested by compression. Our key findings are that the bone matrix secreted during sustained swimming had significantly higher mineral content and mechanical strength, while no effect was detected on bone in vivo architecture. mRNA levels for two mineralization-related genes bgp and alp were significantly upregulated in the exercised fish, indicating promotion of mineralization. The osteocyte density of the lamellar bone of the amphicoel was also significantly higher in the exercised than non-exercised fish, while the osteocyte density in the cancellous bone was similar in the two groups. The vertebral osteocytes did not form a functional syncytium, which shows that salmon vertebral bone responds to mechanical loading in the absence of an extensive connecting syncytial network of osteocytic cell processes as found in mammals, indicating the existence of a different mechanosensing mechanism. The adaptive response to increased load is thus probably mediated by osteoblasts or bone lining cells, a system in which signal detection and response may be co-located. This study offers new insight into the teleost bone biology, and may have implications for maintaining acceptable welfare for farmed salmon. PMID:21615400

  9. Effects of intraspecific variation in reproductive traits, pectoral fin use and burst swimming on metabolic rates and swimming performance in the Trinidadian guppy (Poecilia reticulata).

    PubMed

    Svendsen, Jon C; Banet, Amanda I; Christensen, Rune H B; Steffensen, John F; Aarestrup, Kim

    2013-09-15

    There is considerable intraspecific variation in metabolic rates and locomotor performance in aquatic ectothermic vertebrates; however, the mechanistic basis remains poorly understood. Using pregnant Trinidadian guppies (Poecilia reticulata), a live-bearing teleost, we examined the effects of reproductive traits, pectoral fin use and burst-assisted swimming on swimming metabolic rate, standard metabolic rate (O2std) and prolonged swimming performance (Ucrit). Reproductive traits included reproductive allocation and pregnancy stage, the former defined as the mass of the reproductive tissues divided by the total body mass. Results showed that the metabolic rate increased curvilinearly with swimming speed. The slope of the relationship was used as an index of swimming cost. There was no evidence that reproductive traits correlated with swimming cost, O2std or Ucrit. In contrast, data revealed strong effects of pectoral fin use on swimming cost and Ucrit. Poecilia reticulata employed body-caudal fin (BCF) swimming at all tested swimming speeds; however, fish with a high simultaneous use of the pectoral fins exhibited increased swimming cost and decreased Ucrit. These data indicated that combining BCF swimming and pectoral fin movement over a wide speed range, presumably to support swimming stability and control, is an inefficient swimming behaviour. Finally, transition to burst-assisted swimming was associated with an increase in aerobic metabolic rate. Our study highlights factors other than swimming speed that affect swimming cost and suggests that intraspecific diversity in biomechanical performance, such as pectoral fin use, is an important source of variation in both locomotor cost and maximal performance. PMID:23737561

  10. Burst swimming in areas of high flow: delayed consequences of anaerobiosis in wild adult sockeye salmon.

    PubMed

    Burnett, Nicholas J; Hinch, Scott G; Braun, Douglas C; Casselman, Matthew T; Middleton, Collin T; Wilson, Samantha M; Cooke, Steven J

    2014-01-01

    Wild riverine fishes are known to rely on burst swimming to traverse hydraulically challenging reaches, and yet there has been little investigation as to whether swimming anaerobically in areas of high flow can lead to delayed mortality. Using acoustic accelerometer transmitters, we estimated the anaerobic activity of anadromous adult sockeye salmon (Oncorhynchus nerka) in the tailrace of a diversion dam in British Columbia, Canada, and its effects on the remaining 50 km of their freshwater spawning migration. Consistent with our hypothesis, migrants that elicited burst swimming behaviors in high flows were more likely to succumb to mortality following dam passage. Females swam with more anaerobic effort compared to males, providing a mechanism for the female-biased migration mortality observed in this watershed. Alterations to dam operations prevented the release of hypolimnetic water from an upstream lake, exposing some migrants to supraoptimal, near-lethal water temperatures (i.e., 24°C) that inhibited their ability to locate, enter, and ascend a vertical-slot fishway. Findings from this study have shown delayed post-dam passage survival consequences of high-flow-induced burst swimming in sockeye salmon. We highlight the need for studies to investigate whether dams can impose other carryover effects on wild aquatic animals. PMID:25244372

  11. Use of Chemical Mixtures to Differentiate Mechanisms of Endocrine Action in a Small Fish Model

    EPA Science Inventory

    Various assays with adult fish have been developed to identify potential endocrine-disrupting chemicals (EDCs) which may cause toxicity via alterations in the hypothalamic-pituitary-gonadal (HPG) axis via different mechanisms/modes of action (MOA). These assays can be sensitive ...

  12. Use of Chemical Mixtures to Differentiate Mechanisms of Endocrine Action in a Small Fish Model

    EPA Science Inventory

    Antagonism of the androgen receptor (AR) is an environmentally-relevant mechanism through which the hypothalamic-pituitary-gonadal (HPG) axis of fish can be affected. However, there are few in vivo tests specific for the detection of chemicals that act as AR antagonists. In this ...

  13. [Ontogenetic causes and mechanisms for formation of differences in number of fish scales].

    PubMed

    Levin, B A

    2011-01-01

    Fish scale cover forms in late ontogenesis. Therefore, the conditions of development significantly affect its characteristics (number of scales). This study is aimed at considering the influence of external and internal factors on variation of the number of scales in fish. Acceleration of development results in decrease of the number of scales, while it increases with deceleration. Experiments on regulation of thyroid status of fish showed that the certain mechanism of alteration of the number of scales is related with heterochrony, such as a shift of the laying period of scale cover. Accelerated development is caused by early scale development at smaller body length, while decelerated development is characterized with later scale development and greater body length. Data considering heterochrony as the possible reason for deviations in the number of scales in related fish species are represented. Moreover, alterations of the distance between scales (morphogenetic calculation) can serve as another alteration mechanism of the number of scales in fish (especially phyletically far species). PMID:21786656

  14. Negative gravitactic behavior of Euglena gracilis can not be described by the mechanism of buoyancy-oriented upward swimming

    NASA Astrophysics Data System (ADS)

    Lebert, Michael; Häder, Donat-Peter

    1999-01-01

    Gravitactic behavior of microorganisms has been known for more than a hundred years. Euglena gracilis serves as a model system for gravity-triggered behavioral responses. Two basic mechanisms are discussed for gravitaxis: one is based on a physical mechanism where an asymmetric mass distribution pulls the cell passively in the correct orientation and, in contrast, the involvement of an active sensory system. A recently developed high-resolution motion-tracking system allows the analysis of single tracks during reorientation. The results are compared to a model developed by Fukui and Asai (1985) which describes gravitaxis of Paramecium caudatum on the basis of a physical mechanism. Taking into account the different size, different density, different mass distribution as well as the different velocity, results of the adapted model description of Paramecium were applied to measured data of Euglena. General shapes as well as the time scale of the predicted reorientational movement compared to measurements were different. The analysis clearly rules out the possibility that gravitaxis of Euglena gracilis is based on a pure physical phenomenon, and gives further support to the involvement of an active reorientational system. In addition, it could be shown that cell form changes during reorientation, even in an initial period where no angular change was observed.

  15. Characteristics of velocity distribution functions and entry mechanisms of protons in the near-lunar wake from SWIM/SARA on Chandrayaan-1

    NASA Astrophysics Data System (ADS)

    Dhanya, M. B.; Barabash, Stas; Wieser, Martin; Holmström, Mats; Bhardwaj, Anil; Wurz, Peter; Alok, Abhinaw; Futaana, Yoshifumi

    2016-07-01

    Moon is an airless body with no global magnetic field, although regions of crustal magnetic fields known as magnetic anomalies exist on Moon. Solar wind, the magnetized plasma flow from the Sun, continuously impinges on Moon. Due to the high absorption of solar wind plasma on the lunar dayside, a large scale wake structure is formed downstream of the Moon. However, recent in-situ observations have revealed the presence of protons in the near-lunar wake (100 km to 200 km from the surface). The source of these protons have been found to be the solar wind that enter the wake either directly or after interaction with the lunar surface or with the magnetic anomalies. Using the entire data from the SWIM sensor, which was an ion-mass analyzer, of the SARA experiment onboard Chandrayaan-1, the characteristics of velocity distribution of these protons were investigated to understand the entry mechanisms to near lunar wake. The velocity distribution functions were computed in the two dimensional velocity space, namely in the directions parallel and perpendicular to the IMF (v_allel and v_perp) in the solar wind rest frame. Several proton populations were identified from the velocity distribution and their possible entry mechanism were inferred based on the characteristics of the velocity distribution. These entry mechanisms include (i) diffusion of solar wind protons into the wake along IMF, (ii) the solar wind protons with finite gyro-radii that are aided by the wake boundary electric field, (iii) solar wind protons with gyro-radii larger than lunar radii from the tail of the solar wind velocity distribution, and (iv) scattering of solar wind protons from the dayside lunar surface or from magnetic anomalies. In order to gain more insight into the entry mechanisms associated with different populations, the trajectories of the protons were computed backward in time (backtracing) for each of these populations. For most of the populations, the source mechanism obtained from

  16. Substantial energy expenditure for locomotion in ciliates verified by means of simultaneous measurement of oxygen consumption rate and swimming speed.

    PubMed

    Katsu-Kimura, Yumiko; Nakaya, Fumio; Baba, Shoji A; Mogami, Yoshihiro

    2009-06-01

    In order to characterize the energy expenditure of Paramecium, we simultaneously measured the oxygen consumption rate, using an optic fluorescence oxygen sensor, and the swimming speed, which was evaluated by the optical slice method. The standard metabolic rate (SMR, the rate of energy consumption exclusively for physiological activities other than locomotion) was estimated to be 1.18x10(-6) J h(-1) cell(-1) by extrapolating the oxygen consumption rate into one at zero swimming speed. It was about 30% of the total energy consumed by the cell swimming at a mean speed of 1 mm s(-1), indicating that a large amount of the metabolic energy (about 70% of the total) is consumed for propulsive activity only. The mechanical power liberated to the environment by swimming Paramecium was calculated on the basis of Stokes' law. This power, termed Stokes power, was 2.2x10(-9) J h(-1) cell(-1), indicating extremely low efficiency (0.078%) in the conversion of metabolic power to propulsion. Analysis of the cost of transport (COT, the energy expenditure for translocation per units of mass and distance) revealed that the efficiency of energy expenditure in swimming increases with speed rather than having an optimum value within a wide range of forced swimming, as is generally found in fish swimming. These characteristics of energy expenditure would be unique to microorganisms, including Paramecium, living in a viscous environment where large dissipation of the kinetic energy is inevitable due to the interaction with the surrounding water. PMID:19482999

  17. Analysis of swimming motions.

    NASA Technical Reports Server (NTRS)

    Gallenstein, J.; Huston, R. L.

    1973-01-01

    This paper presents an analysis of swimming motion with specific attention given to the flutter kick, the breast-stroke kick, and the breast stroke. The analysis is completely theoretical. It employs a mathematical model of the human body consisting of frustrums of elliptical cones. Dynamical equations are written for this model including both viscous and inertia forces. These equations are then applied with approximated swimming strokes and solved numerically using a digital computer. The procedure is to specify the input of the swimming motion. The computer solution then provides the output displacement, velocity, and rotation or body roll of the swimmer.

  18. Vulnerability of individual fish to capture by trawling is influenced by capacity for anaerobic metabolism

    PubMed Central

    Killen, Shaun S.; Nati, Julie J. H.; Suski, Cory D.

    2015-01-01

    The harvest of animals by humans may constitute one of the strongest evolutionary forces affecting wild populations. Vulnerability to harvest varies among individuals within species according to behavioural phenotypes, but we lack fundamental information regarding the physiological mechanisms underlying harvest-induced selection. It is unknown, for example, what physiological traits make some individual fish more susceptible to capture by commercial fisheries. Active fishing methods such as trawling pursue fish during harvest attempts, causing fish to use both aerobic steady-state swimming and anaerobic burst-type swimming to evade capture. Using simulated trawling procedures with schools of wild minnows Phoxinus phoxinus, we investigate two key questions to the study of fisheries-induced evolution that have been impossible to address using large-scale trawls: (i) are some individuals within a fish shoal consistently more susceptible to capture by trawling than others?; and (ii) if so, is this related to individual differences in swimming performance and metabolism? Results provide the first evidence of repeatable variation in susceptibility to trawling that is strongly related to anaerobic capacity and swimming ability. Maximum aerobic swim speed was also negatively correlated with vulnerability to trawling. Standard metabolic rate was highest among fish that were least vulnerable to trawling, but this relationship probably arose through correlations with anaerobic capacity. These results indicate that vulnerability to trawling is linked to anaerobic swimming performance and metabolic demand, drawing parallels with factors influencing susceptibility to natural predators. Selection on these traits by fisheries could induce shifts in the fundamental physiological makeup and function of descendent populations. PMID:26246542

  19. Vulnerability of individual fish to capture by trawling is influenced by capacity for anaerobic metabolism.

    PubMed

    Killen, Shaun S; Nati, Julie J H; Suski, Cory D

    2015-08-22

    The harvest of animals by humans may constitute one of the strongest evolutionary forces affecting wild populations. Vulnerability to harvest varies among individuals within species according to behavioural phenotypes, but we lack fundamental information regarding the physiological mechanisms underlying harvest-induced selection. It is unknown, for example, what physiological traits make some individual fish more susceptible to capture by commercial fisheries. Active fishing methods such as trawling pursue fish during harvest attempts, causing fish to use both aerobic steady-state swimming and anaerobic burst-type swimming to evade capture. Using simulated trawling procedures with schools of wild minnows Phoxinus phoxinus, we investigate two key questions to the study of fisheries-induced evolution that have been impossible to address using large-scale trawls: (i) are some individuals within a fish shoal consistently more susceptible to capture by trawling than others?; and (ii) if so, is this related to individual differences in swimming performance and metabolism? Results provide the first evidence of repeatable variation in susceptibility to trawling that is strongly related to anaerobic capacity and swimming ability. Maximum aerobic swim speed was also negatively correlated with vulnerability to trawling. Standard metabolic rate was highest among fish that were least vulnerable to trawling, but this relationship probably arose through correlations with anaerobic capacity. These results indicate that vulnerability to trawling is linked to anaerobic swimming performance and metabolic demand, drawing parallels with factors influencing susceptibility to natural predators. Selection on these traits by fisheries could induce shifts in the fundamental physiological makeup and function of descendent populations. PMID:26246542

  20. Evolution of levers and linkages in the feeding mechanisms of fishes.

    PubMed

    Westneat, Mark W

    2004-11-01

    The evolution of feeding mechanisms in the ray-finned fishes (Actinopterygii) is a compelling example of transformation in a musculoskeletal complex involving multiple skeletal elements and numerous muscles that power skull motion. Biomechanical models of jaw force and skull kinetics aid our understanding of these complex systems and enable broad comparison of feeding mechanics across taxa. Mechanical models characterize how muscles move skeletal elements by pulling bones around points of rotation in lever mechanisms, or by transmitting force through skeletal elements connected in a linkage. Previous work has focused on the feeding biomechanics of several lineages of fishes, but a broader survey of skull function in the context of quantitative models has not been attempted. This study begins such a survey by examining the diversity of mechanical design of the oral jaws in 35 species of ray-finned fishes with three main objectives: (1) analyze lower jaw lever models in a broad phylogenetic range of taxa, (2) identify the origin and evolutionary patterns of change in the linkage systems that power maxillary rotation and upper jaw protrusion, and (3) analyze patterns of change in feeding design in the context of actinopterygian phylogeny. The mandibular lever is present in virtually all actinopterygians, and the diversity in lower jaw closing force transmission capacity, with mechanical advantage ranging from 0.04 to 0.68, has important functional consequences. A four-bar linkage for maxillary rotation arose in the Amiiformes and persists in various forms in many teleost species. Novel mechanisms for upper jaw protrusion based on this linkage for maxillary rotation have evolved independently at least five times in teleosts. The widespread anterior jaws linkage for jaw protrusion in percomorph fishes arose initially in Zeiformes and subsequently radiated into a wide range of premaxillary protrusion capabilities. PMID:21676723

  1. Undulatory locomotion of flexible foils as biomimetic models for understanding fish propulsion.

    PubMed

    Shelton, Ryan M; Thornycroft, Patrick J M; Lauder, George V

    2014-06-15

    An undulatory pattern of body bending in which waves pass along the body from head to tail is a major mechanism of creating thrust in many fish species during steady locomotion. Analyses of live fish swimming have provided the foundation of our current understanding of undulatory locomotion, but our inability to experimentally manipulate key variables such as body length, flexural stiffness and tailbeat frequency in freely swimming fish has limited our ability to investigate a number of important features of undulatory propulsion. In this paper we use a mechanical flapping apparatus to create an undulatory wave in swimming flexible foils driven with a heave motion at their leading edge, and compare this motion with body bending patterns of bluegill sunfish (Lepomis macrochirus) and clown knifefish (Notopterus chitala). We found similar swimming speeds, Reynolds and Strouhal numbers, and patterns of curvature and shape between these fish and foils, suggesting that flexible foils provide a useful model for understanding fish undulatory locomotion. We swam foils with different lengths, stiffnesses and heave frequencies while measuring forces, torques and hydrodynamics. From measured forces and torques we calculated thrust and power coefficients, work and cost of transport for each foil. We found that increasing frequency and stiffness produced faster swimming speeds and more thrust. Increasing length had minimal impact on swimming speed, but had a large impact on Strouhal number, thrust coefficient and cost of transport. Foils that were both stiff and long had the lowest cost of transport (in mJ m(-1) g(-1)) at low cycle frequencies, and the ability to reach the highest speed at high cycle frequencies. PMID:24625649

  2. Biomimetic and bio-inspired robotics in electric fish research.

    PubMed

    Neveln, Izaak D; Bai, Yang; Snyder, James B; Solberg, James R; Curet, Oscar M; Lynch, Kevin M; MacIver, Malcolm A

    2013-07-01

    Weakly electric knifefish have intrigued both biologists and engineers for decades with their unique electrosensory system and agile swimming mechanics. Study of these fish has resulted in models that illuminate the principles behind their electrosensory system and unique swimming abilities. These models have uncovered the mechanisms by which knifefish generate thrust for swimming forward and backward, hovering, and heaving dorsally using a ventral elongated median fin. Engineered active electrosensory models inspired by electric fish allow for close-range sensing in turbid waters where other sensing modalities fail. Artificial electrosense is capable of aiding navigation, detection and discrimination of objects, and mapping the environment, all tasks for which the fish use electrosense extensively. While robotic ribbon fin and artificial electrosense research has been pursued separately to reduce complications that arise when they are combined, electric fish have succeeded in their ecological niche through close coupling of their sensing and mechanical systems. Future integration of electrosense and ribbon fin technology into a knifefish robot should likewise result in a vehicle capable of navigating complex 3D geometries unreachable with current underwater vehicles, as well as provide insights into how to design mobile robots that integrate high bandwidth sensing with highly responsive multidirectional movement. PMID:23761475

  3. Swimming & Propulsion in Viscoelastic Media

    NASA Astrophysics Data System (ADS)

    Arratia, Paulo

    2012-02-01

    Many microorganisms have evolved within complex fluids, which include soil, intestinal fluid, and mucus. The material properties or rheology of such fluids can strongly affect an organism's swimming behavior. A major challenge is to understand the mechanism of propulsion in media that exhibit both solid- and fluid-like behavior, such as viscoelastic fluids. In this talk, we present experiments that explore the swimming behavior of biological organisms and artificial particles in viscoelastic media. The organism is the nematode Caenorhabditis elegans, a roundworm widely used for biological research that swims by generating traveling waves along its body. Overall, we find that fluid elasticity hinders self-propulsion compared to Newtonian fluids due to the enhanced resistance to flow near hyperbolic points for viscoelastic fluids. As fluid elasticity increases, the nematode's propulsion speed decreases. These results are consistent with recent theoretical models for undulating sheets and cylinders. In order to gain further understanding on propulsion in viscoelastic media, we perform experiments with simple reciprocal artificial `swimmers' (magnetic dumbbell particles) in polymeric and micellar solutions. We find that self-propulsion is possible in viscoelastic media even if the motion is reciprocal.

  4. Swim Safely This Summer

    MedlinePlus

    ... all ages to follow safety rules at the beach or pool. Swim in designated areas supervised by ... to RSS Follow us Disclaimers Copyright Privacy Accessibility Quality Guidelines Viewers & Players MedlinePlus Connect for EHRs For ...

  5. Fish under exercise.

    PubMed

    Palstra, Arjan P; Planas, Josep V

    2011-06-01

    Improved knowledge on the swimming physiology of fish and its application to fisheries science and aquaculture (i.e., farming a fitter fish) is currently needed in the face of global environmental changes, high fishing pressures, increased aquaculture production as well as increased concern on fish well-being. Here, we review existing data on teleost fish that indicate that sustained exercise at optimal speeds enhances muscle growth and has consequences for flesh quality. Potential added benefits of sustained exercise may be delay of ovarian development and stimulation of immune status. Exercise could represent a natural, noninvasive, and economical approach to improve growth, flesh quality as well as welfare of aquacultured fish: a FitFish for a healthy consumer. All these issues are important for setting directions for policy decisions and future studies in this area. For this purpose, the FitFish workshop on the Swimming Physiology of Fish ( http://www.ub.edu/fitfish2010 ) was organized to bring together a multidisciplinary group of scientists using exercise models, industrial partners, and policy makers. Sixteen international experts from Europe, North America, and Japan were invited to present their work and view on migration of fishes in their natural environment, beneficial effects of exercise, and applications for sustainable aquaculture. Eighty-eight participants from 19 different countries contributed through a poster session and round table discussion. Eight papers from invited speakers at the workshop have been contributed to this special issue on The Swimming Physiology of Fish. PMID:21611721

  6. Swimming near the substrate: a simple robotic model of stingray locomotion.

    PubMed

    Blevins, Erin; Lauder, George V

    2013-03-01

    Studies of aquatic locomotion typically assume that organisms move through unbounded fluid. However, benthic fishes swim close to the substrate and will experience significant ground effects, which will be greatest for fishes with wide spans such as benthic batoids and flatfishes. Ground effects on fixed-wing flight are well understood, but these models are insufficient to describe the dynamic interactions between substrates and undulating, oscillating fish. Live fish alter their swimming behavior in ground effect, complicating comparisons of near-ground and freestream swimming performance. In this study, a simple, stingray-inspired physical model offers insights into ground effects on undulatory swimmers, contrasting the self-propelled swimming speed, power requirements, and hydrodynamics of fins swimming with fixed kinematics near and far from a solid boundary. Contrary to findings for gliding birds and other fixed-wing fliers, ground effect does not necessarily enhance the performance of undulating fins. Under most kinematic conditions, fins do not swim faster in ground effect, power requirements increase, and the cost of transport can increase by up to 10%. The influence of ground effect varies with kinematics, suggesting that benthic fish might modulate their swimming behavior to minimize locomotor penalties and incur benefits from swimming near a substrate. PMID:23318215

  7. The mechanism by which fish antifreeze proteins cause thermal hysteresis.

    PubMed

    Kristiansen, Erlend; Zachariassen, Karl Erik

    2005-12-01

    Antifreeze proteins are characterised by their ability to prevent ice from growing upon cooling below the bulk melting point. This displacement of the freezing temperature of ice is limited and at a sufficiently low temperature a rapid ice growth takes place. The separation of the melting and freezing temperature is usually referred to as thermal hysteresis, and the temperature of ice growth is referred to as the hysteresis freezing point. The hysteresis is supposed to be the result of an adsorption of antifreeze proteins to the crystal surface. This causes the ice to grow as convex surface regions between adjacent adsorbed antifreeze proteins, thus lowering the temperature at which the crystal can visibly expand. The model requires that the antifreeze proteins are irreversibly adsorbed onto the ice surface within the hysteresis gap. This presupposition is apparently in conflict with several characteristic features of the phenomenon; the absence of superheating of ice in the presence of antifreeze proteins, the dependence of the hysteresis activity on the concentration of antifreeze proteins and the different capacities of different types of antifreeze proteins to cause thermal hysteresis at equimolar concentrations. In addition, there are structural obstacles that apparently would preclude irreversible adsorption of the antifreeze proteins to the ice surface; the bond strength necessary for irreversible adsorption and the absence of a clearly defined surface to which the antifreeze proteins may adsorb. This article deals with these apparent conflicts between the prevailing theory and the empirical observations. We first review the mechanism of thermal hysteresis with some modifications: we explain the hysteresis as a result of vapour pressure equilibrium between the ice surface and the ambient fluid fraction within the hysteresis gap due to a pressure build-up within the convex growth zones, and the ice growth as the result of an ice surface nucleation event at

  8. Is paramecium swimming autonomic?

    NASA Astrophysics Data System (ADS)

    Bandyopadhyay, Promode R.; Toplosky, Norman; Hansen, Joshua

    2010-11-01

    We seek to explore if the swimming of paramecium has an underlying autonomic mechanism. Such robotic elements may be useful in capturing the disturbance field in an environment in real time. Experimental evidence is emerging that motion control neurons of other animals may be present in paramecium as well. The limit cycle determined using analog simulation of the coupled nonlinear oscillators of olivo-cerebellar dynamics (ieee joe 33, 563-578, 2008) agrees with the tracks of the cilium of a biological paramecium. A 4-motor apparatus has been built that reproduces the kinematics of the cilium motion. The motion of the biological cilium has been analyzed and compared with the results of the finite element modeling of forces on a cilium. The modeling equates applied torque at the base of the cilium with drag, the cilium stiffness being phase dependent. A low friction pendulum apparatus with a multiplicity of electromagnetic actuators is being built for verifying the maps of the attractor basin computed using the olivo-cerebellar dynamics for different initial conditions. Sponsored by ONR 33.

  9. Surveillance and Conformity in Competitive Youth Swimming

    ERIC Educational Resources Information Center

    Lang, Melanie

    2010-01-01

    Underpinned by a Foucauldian analysis of sporting practices, this paper identifies the disciplinary mechanism of surveillance at work in competitive youth swimming. It highlights the ways in which swimmers and their coaches are subject to and apply this mechanism to produce embodied conformity to normative behaviour and obedient, docile bodies.…

  10. Pyrethroid Pesticides as Endocrine Disruptors: Molecular Mechanisms in Vertebrates with a Focus on Fishes.

    PubMed

    Brander, Susanne M; Gabler, Molly K; Fowler, Nicholas L; Connon, Richard E; Schlenk, Daniel

    2016-09-01

    Pyrethroids are now the fourth most used group of insecticides worldwide. Employed in agriculture and in urban areas, they are detected in waterways at concentrations that are lethally and sublethally toxic to aquatic organisms. Highly lipophilic, pyrethroids accumulate in sediments and bioaccumulate in fishes. Additionally, these compounds are demonstrated to act as endocrine disrupting compounds (or EDCs) in mammals and fishes, and therefore interfere with endocrine signaling by blocking, mimicking, or synergizing endogenous hormones through direct receptor interactions, and indirectly via upstream signaling pathways. Pyrethroid metabolites have greater endocrine activity than their parent structures, and this activity is dependent on the enantiomer present, as some pyrethroids are chiral. Many EDCs studied thus far in fish have known estrogenic or antiestrogenic effects, and as such cause the inappropriate or altered expression of genes or proteins (i.e., Vtg-vitellogenin, Chg-choriogenin), often leading to physiological or reproductive effects. Additionally, these compounds can also interfere with other endocrine pathways and immune response. This review highlights studies that focus on the mechanisms of pyrethroid biotransformation and endocrine toxicity to fishes across a broad range of different pyrethroid types, and integrates literature on the in vitro and mammalian responses that inform these mechanisms. PMID:27464030

  11. Flapping flexible fish

    NASA Astrophysics Data System (ADS)

    Root, Robert G.; Courtland, Hayden-William; Shepherd, William; Long, John H.

    In order to analyze and model the body kinematics used by fish in a wide range of swimming behaviors, we developed a technique to separate the periodic whole-body motions that characterize steady swimming from the secular motions that characterize changes in whole-body shape. We applied this harmonic analysis technique to the study of the forward and backward swimming of lamprey. We found that in order to vary the unsteadiness of swimming, lamprey superimpose periodic and secular components of their body motion, modulate the patterns and magnitudes of those components, and change shape. These kinematic results suggest the following hydromechanical hypothesis: steady swimming is a maneuver that requires active suppression of secular body reconfigurations.

  12. Swimming performance of young lake trout after chronic exposure to PCBs and DDE

    USGS Publications Warehouse

    Rottiers, Donald V.; Bergstedt, Roger A.

    1981-01-01

    Swimming performance was measured in fry of lake trout (Salvelinus namaycush) exposed to PCB's, DDE, and a combination of these two contaminants in both food and water at concentrations equal to, and 5 and 25 times higher than, levels found in Lake Michigan water and plankton. Fry were tested after about 50, 110, and 165 days of exposure. We measured swimming performance by forcing the fry to swim through a continuous series of incrementally increased velocities until the fish were exhausted. Although we observed significant differences in swimming performance between a few test groups, we detected no relation between swimming performance of the fry and exposure to PCB's or DDE, or both, at the concentrations tested. Inasmuch as swimming performance apparently was not affected by the levels of contamination by PCB's and DDE in Lake Michigan, impairment of swimming by these contaminants cannot account for the failure of lake trout reproduction in Lake Michigan.

  13. Swim performance and energy homeostasis in spottail shiner (Notropis hudsonius) collected downstream of a uranium mill.

    PubMed

    Goertzen, Meghan M; Hauck, Dominic W; Phibbs, James; Weber, Lynn P; Janz, David M

    2012-01-01

    The Key Lake uranium milling operation (Saskatchewan, Canada) releases complex effluent into the local watershed. The objective of the current study was to investigate whether fish from an effluent-receiving waterbody exhibited differences in swimming performance and energy homeostasis compared to fish from a local reference site. Juvenile spottail shiner (Notropis hudsonius) were collected from a lake downstream of the uranium mill, and compared to fish collected from a nearby reference lake. Critical swimming speed (U(crit); fatigue velocity), tail beat frequency, and tail amplitude did not differ significantly when comparing fish collected from the exposure lake and reference lake. Captured shiner used in swim tests were considered fatigued, and metabolic endpoints were compared between this group and non-fatigued fish, which were treated similarly but not subjected to swim tests. In both non-fatigued and fatigued shiner, liver glycogen was significantly greater in fish collected from the exposure lake compared to the reference lake. However, it is unclear if this effect, and others related to condition, were the result of contaminant exposure or other environmental factors. While there were no differences in plasma lactate, hematocrit or liver triglycerides in non-fatigued fish between sites, only fatigued reference fish had increased lactate and hematocrit and decreased triglycerides. In non-fatigued fish, plasma glucose did not significantly differ between sites, but significantly decreased after swimming only in fish from the exposure lake. In summary, shiner from the exposure site demonstrated similar swim endurance and possessed greater energy stores despite metabolic alterations compared to shiner from the reference site. Therefore, because fish collected downstream of the uranium mill operation had similar swimming ability as fish from the reference lake, U(crit) test results presented here may not reflect or be indicative of metabolic effects of complex

  14. Effect of chemical composition and microstructure on the mechanical behavior of fish scales from Megalops Atlanticus.

    PubMed

    Gil-Duran, S; Arola, D; Ossa, E A

    2016-03-01

    This paper presents an experimental study of the composition, microstructure and mechanical behavior of scales from the Megalops Atlanticus (Atlantic tarpon). The microstructure and composition were evaluated by Scanning Electron Microscopy (SEM) and RAMAN spectroscopy, respectively. The mechanical properties were evaluated in uniaxial tension as a function of position along the length of the fish (head, mid-length and tail). Results showed that the scales are composed of collagen and hydroxyapatite, and these constituents are distributed within three well-defined layers from the bottom to the top of the scale. The proportion of these layers with respect to the total scale thickness varies radially. The collagen fibers are arranged in plies with different orientations and with preferred orientation in the longitudinal direction of the fish. Results from the tensile tests showed that scales from Megalops Atlanticus exhibit variations in the elastic modulus as a function of body position. Additional testing performed with and without the highly mineralized top layers of the scale revealed that the mechanical behavior is anisotropic and that the highest strength was exhibited along the fish length. Furthermore, removing the top mineralized layers resulted in an increase in the tensile strength of the scale. PMID:26703228

  15. The archaellum: how Archaea swim

    PubMed Central

    Albers, Sonja-Verena; Jarrell, Ken F.

    2015-01-01

    Recent studies on archaeal motility have shown that the archaeal motility structure is unique in several aspects. Although it fulfills the same swimming function as the bacterial flagellum, it is evolutionarily and structurally related to the type IV pilus. This was the basis for the recent proposal to term the archaeal motility structure the “archaellum.” This review illustrates the key findings that led to the realization that the archaellum was a novel motility structure and presents the current knowledge about the structural composition, mechanism of assembly and regulation, and the posttranslational modifications of archaella. PMID:25699024

  16. Upstream Swimming in Microbiological Flows.

    PubMed

    Mathijssen, Arnold J T M; Shendruk, Tyler N; Yeomans, Julia M; Doostmohammadi, Amin

    2016-01-15

    Interactions between microorganisms and their complex flowing environments are essential in many biological systems. We develop a model for microswimmer dynamics in non-Newtonian Poiseuille flows. We predict that swimmers in shear-thickening (-thinning) fluids migrate upstream more (less) quickly than in Newtonian fluids and demonstrate that viscoelastic normal stress differences reorient swimmers causing them to migrate upstream at the centerline, in contrast to well-known boundary accumulation in quiescent Newtonian fluids. Based on these observations, we suggest a sorting mechanism to select microbes by swimming speed. PMID:26824571

  17. Upstream Swimming in Microbiological Flows

    NASA Astrophysics Data System (ADS)

    Mathijssen, Arnold J. T. M.; Shendruk, Tyler N.; Yeomans, Julia M.; Doostmohammadi, Amin

    2016-01-01

    Interactions between microorganisms and their complex flowing environments are essential in many biological systems. We develop a model for microswimmer dynamics in non-Newtonian Poiseuille flows. We predict that swimmers in shear-thickening (-thinning) fluids migrate upstream more (less) quickly than in Newtonian fluids and demonstrate that viscoelastic normal stress differences reorient swimmers causing them to migrate upstream at the centerline, in contrast to well-known boundary accumulation in quiescent Newtonian fluids. Based on these observations, we suggest a sorting mechanism to select microbes by swimming speed.

  18. Swimming pool. View of aisle between swimming pool and seating ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Swimming pool. View of aisle between swimming pool and seating area. Non-original spa pool is partially visible on right. - Jewish Community Center of San Francisco, 3200 California Street, San Francisco, San Francisco County, CA

  19. Macrocomposite mechanical design, modeling, and behavior of physical models of bioinspired fish armor

    NASA Astrophysics Data System (ADS)

    Browning, Ashley; Ortiz, Christine; Boyce, Mary C.

    2012-02-01

    The macrocomposite design of flexible biological exoskeletons, consisting of overlapping mineralized armor units embedded in a compliant tissue, is a key determinant of their mechanical function (e.g penetration resistance and biomechanical flexibility). Here, we investigate the role of macrocomposite structure, composition, geometric orientation, and spatial distribution in a flexible model natural armor system present in the majority of teleost fish species. Physical multi-material composite models are fabricated using a combination of 3-D printing and molding methods. Mechanical experiments using digital image correlation enable measurement of both the macroscopic response and underlying deformation mechanisms during various loading scenarios. Finite element-based mechanical models yield detailed insights into the roles and the tradeoffs of the composite structure providing constraint, shear, and bending mechanisms to impart protection and flexibility.

  20. Swimming behaviour of juvenile Pacific lamprey, Lampetra tridentata

    SciTech Connect

    Dauble, Dennis D.; Moursund, Russell A.; Bleich, Matthew D.

    2006-02-01

    Actively migrating juvenile Pacific lamprey (Lampetra tridentata Richardson, 1836) were collected from hydroelectric bypass facilities in the Columbia River and transferred to the laboratory to study their diel movement patterns and swimming ability. Volitional movement of lamprey was restricted mainly to night, with 94% of all swimming activity occurring during the 12-hr dark period. Burst speed of juvenile lamprey ranged from 56 to 94 cm/s with a mean of 71 ±5 cm/s or an average speed of 5.2 body lengths (BL)/s. Sustained swim speed for 5-min test intervals ranged from 0 to 46 cm/s with a median of 23 cm/s. Critical swimming speed was 36.0±10.0 cm/s and 2.4±0.6 BL/s. There was no significant relationship between fish length and critical swimming speed. Overall swimming performance of juvenile Pacific lamprey is low compared to that of most anadromous teleosts. Their poor swimming ability provides a challenge during the freshwater migration interval to the Pacific Ocean.

  1. Optimal shape and motion of undulatory swimming organisms

    PubMed Central

    Tokić, Grgur; Yue, Dick K. P.

    2012-01-01

    Undulatory swimming animals exhibit diverse ranges of body shapes and motion patterns and are often considered as having superior locomotory performance. The extent to which morphological traits of swimming animals have evolved owing to primarily locomotion considerations is, however, not clear. To shed some light on that question, we present here the optimal shape and motion of undulatory swimming organisms obtained by optimizing locomotive performance measures within the framework of a combined hydrodynamical, structural and novel muscular model. We develop a muscular model for periodic muscle contraction which provides relevant kinematic and energetic quantities required to describe swimming. Using an evolutionary algorithm, we performed a multi-objective optimization for achieving maximum sustained swimming speed U and minimum cost of transport (COT)—two conflicting locomotive performance measures that have been conjectured as likely to increase fitness for survival. Starting from an initial population of random characteristics, our results show that, for a range of size scales, fish-like body shapes and motion indeed emerge when U and COT are optimized. Inherent boundary-layer-dependent allometric scaling between body mass and kinematic and energetic quantities of the optimal populations is observed. The trade-off between U and COT affects the geometry, kinematics and energetics of swimming organisms. Our results are corroborated by empirical data from swimming animals over nine orders of magnitude in size, supporting the notion that optimizing U and COT could be the driving force of evolution in many species. PMID:22456876

  2. Swimming Pools and Molluscum Contagiosum

    MedlinePlus

    ... Travelers' Health: Smallpox & Other Orthopoxvirus-Associated Infections Poxvirus Swimming Pools Recommend on Facebook Tweet Share Compartir The ... often ask if molluscum virus can spread in swimming pools. There is also concern that it can ...

  3. Swimming Near the Wall

    NASA Astrophysics Data System (ADS)

    Quinn, Daniel; Moored, Keith; Dewey, Peter; Lauder, George; Smits, Alexander

    2012-11-01

    The aerodynamic loads on rectangular panels undergoing heave and pitch oscillations near a solid wall were measured using a 6-axis ATI sensor. Over a range of Strouhal numbers, reduced frequencies and flexibilities, swimming near the wall was found to increase thrust and therefore the self-propelled swimming speed. Experimental particle image velocimetry revealed an asymmetric wake structure with a momentum jet angled away from the wall. Both the thrust amplification and the asymmetric wake structure were verified and investigated further using an in-house inviscid panel method code. Supported by ONR MURI Grant N00014-08-1-0642.

  4. Effect of dielectrophoretic force on swimming bacteria.

    PubMed

    Tran, Ngoc Phu; Marcos

    2015-07-01

    Dielectrophoresis (DEP) has been applied widely in bacterial manipulation such as separating, concentrating, and focusing. Previous studies primarily focused on the collective effects of DEP force on the bacterial population. However, the influence of DEP force on the swimming of a single bacterium had not been investigated. In this study, we present a model to analyze the effect of DEP force on a swimming helically flagellated bacterium, particularly on its swimming direction and velocity. We consider a simple DEP force that acts along the X-direction, and its strength as well as direction varies with the X- and Y-positions. Resistive force theory is employed to compute the hydrodynamic force on the bacterium's flagellar bundle, and the effects of both DEP force and rotational diffusion on the swimming of the bacterium are simultaneously taken into consideration using the Fokker-Planck equation. We show the mechanism of how DEP force alters the orientation and velocity of the bacterium. In most cases, the DEP force dominantly influences the orientation of the swimming bacterium; however, when the DEP force strongly varies along the Y-direction, the rotational diffusion is also responsible for determining the bacterium's reorientation. More interestingly, the variance of DEP force along the Y-direction causes the bacterium to experience a translational velocity perpendicular to its primary axis, and this phenomenon could be utilized to focus the bacteria. Finally, we show the feasibility of applying our findings to achieve bacterial focusing. PMID:25785901

  5. How animals drink and swim in fluids

    NASA Astrophysics Data System (ADS)

    Jung, Sunghwan

    2011-10-01

    Fluids are essential for most living organisms to maintain a healthy body and also serve as a medium in which they locomote. The fluid bulk or interfaces actively interact with biological structures, which produces highly nonlinear, interesting, and complicated dynamical problems. We studied the lapping of cats and the swimming of Paramecia in various fluidic environments. The problem of the cat drinking can be simplified as the competition between inertia and gravity whereas the problem of Paramecium swimming in viscous fluids results from the competition between viscous drag and thrust. The underlying mechanisms are discussed and understood through laboratory experiments utilizing high-speed photography.

  6. Study of Fish Response Using Particle Image Velocimetry and High-Speed, High-Resolution Imaging

    SciTech Connect

    Deng, Zhiqun; Richmond, Marshall C.; Guensch, Gregory R.; Mueller, Robert P.

    2004-10-23

    Existing literature of previous particle image velocimetry (PIV) studies of fish swimming has been reviewed. Historically, most of the studies focused on the performance evaluation of freely swimming fish. Technological advances over the last decade, especially the development of digital particle image velocimetry (DPIV) technique, make possible more accurate, quantitative descriptions of the flow patterns adjacent to the fish and in the wake behind the fins and tail, which are imperative to decode the mechanisms of drag reduction and propulsive efficiency. For flows generated by different organisms, the related scales and flow regimes vary significantly. For small Reynolds numbers, viscosity dominates; for very high Reynolds numbers, inertia dominates, and three-dimensional complexity occurs. The majority of previous investigations dealt with the lower end of Reynolds number range. The fish of our interest, such as rainbow trout and spring and fall chinook salmon, fall into the middle range, in which neither viscosity nor inertia is negligible, and three-dimensionality has yet to dominate. Feasibility tests have proven the applicability of PIV to flows around fish. These tests have shown unsteady vortex shedding in the wake, high vorticity region and high stress region, with the highest in the pectoral area. This evident supports the observations by Nietzel et al. (2000) and Deng et al. (2004) that the operculum are most vulnerable to damage from the turbulent shear flow, because they are easily pried open, and the large vorticity and shear stress can lift and tear off scales, rupture or dislodge eyes, and damage gills. In addition, the unsteady behavior of the vortex shedding in the wake implies that injury to fish by the instantaneous flow structures would likely be much higher than the injury level estimated using the average values of the dynamics parameters. Based on existing literature, our technological capability, and relevance and practicability to

  7. Undulatory swimming in fluids with polymer networks

    NASA Astrophysics Data System (ADS)

    Gagnon, D. A.; Shen, X. N.; Arratia, P. E.

    2013-10-01

    The motility behavior of the nematode Caenorhabditis elegans in polymeric solutions of varying concentrations is systematically investigated in experiments using tracking and velocimetry methods. As the polymer concentration is increased, the solution undergoes a transition from the semi-dilute to the concentrated regime, where these rod-like polymers entangle, align, and form networks. Remarkably, we find an enhancement in the nematode's swimming speed of approximately 65% in concentrated solutions compared to semi-dilute solutions. Using velocimetry methods, we show that the undulatory swimming motion of the nematode induces an anisotropic mechanical response in the fluid. This anisotropy, which arises from the fluid micro-structure, is responsible for the observed increase in swimming speed.

  8. Undulatory Swimming in Fluids with Polymer Networks

    NASA Astrophysics Data System (ADS)

    Gagnon, David; Shen, Xiaoning; Arratia, Paulo

    2013-11-01

    In this talk, we systematically investigate the motility behavior of the nematode Caenorhabditis elegans in polymeric solutions of varying concentration using tracking and velocimetry methods. As the polymer concentration is increased, the solution undergoes a transition from the semi-dilute to the concentrated regime, where these rod-like polymers entangle, align, and form networks. Remarkably, we find an enhancement in the nematode's swimming speed of approximately 65 percent in concentrated solutions compared to semi-dilute solutions. Using velocimetry methods, we show that the undulatory swimming motion of the nematode induces an anisotropic mechanical response in the fluid. This anisotropy, which arises from the fluid micro-structure, is responsible for the observed increase in swimming speed. This work was supported by NSF CAREER (CBET) 0954084.

  9. Red Cross Swimming Update.

    ERIC Educational Resources Information Center

    Vlasich, Cynthia

    1989-01-01

    Six new aquatic courses, developed by the Red Cross, are described. They are: Infant and Preschool Aquatics, Longfellow's Whale Tales (classroom water safety lessons for K-Six), Basic Water Safety, Emergency Water Safety, Lifeguard Training, and Safety Training for Swim Coaches. (IAH)

  10. Salinity-dependent mechanisms of copper toxicity in the galaxiid fish, Galaxias maculatus.

    PubMed

    Glover, Chris N; Urbina, Mauricio A; Harley, Rachel A; Lee, Jacqueline A

    2016-05-01

    The euryhaline galaxiid fish, inanga (Galaxias maculatus) is widely spread throughout the Southern hemisphere occupying near-coastal streams that may be elevated in trace elements such as copper (Cu). Despite this, nothing is known regarding their sensitivity to Cu contamination. The mechanisms of Cu toxicity in inanga, and the ameliorating role of salinity, were investigated by acclimating fish to freshwater (FW), 50% seawater (SW), or 100% SW and exposing them to a graded series of Cu concentrations (0-200μgL(-1)) for 48h. Mortality, whole body Cu accumulation, measures of ionoregulatory disturbance (whole body ions, sodium (Na) influx, sodium/potassium ATPase activity) and ammonia excretion were monitored. Toxicity of Cu was greatest in FW, with mortality likely resulting from impaired Na influx. In both FW and 100% SW, ammonia excretion was significantly elevated, an effect opposite to that observed in previous studies, suggesting fundamental differences in the effect of Cu in this species relative to other studied fish. Salinity was protective against Cu toxicity, and physiology seemed to play a more important role than water chemistry in this protection. Inanga are sensitive to waterborne Cu through a conserved impairment of Na ion homeostasis, but some effects of Cu exposure in this species are distinct. Based on effect concentrations, current regulatory tools and limits are likely protective of this species in New Zealand waters. PMID:26966874

  11. [Mechanisms of Cr (VI) toxicity to fish in aquatic environment: A review].

    PubMed

    Chen, Hong-xing; Wu, Xing; Bi, Ran; Li, Li-xia; Gao, Mi; Li, Dan; Xie, Ling-tian

    2015-10-01

    With increasing consumption and applications of chromium in metallurgy, electroplating, tanning process and stainless steel industry, chromium contamination has become a global environmental problem. In general, Cr(VI) has higher permeability across the cell membrane than Cr(III) and hence is considered more toxic than Cr(III). Oxidative stress could be induced following reactive oxygen species (ROS) normally produced in fish under Cr(VI) exposure due to its variable valences. Furthermore, the intermediates of Cr, e.g. Cr(V) and Cr(IV) , produced by cellular reduction processes can bind with DNA and result in mutagenic effects. These combined effects will threaten the growth, development and population structure of different fish species. In this paper, we reviewed published results on the toxic effects of Cr(VI) in fish at levels of molecules, tissues, organs and individuals. The mechanisms of toxicity and detoxification of Cr(VI) in various aspects were discussed. In addition, we also put forward perspectives on the toxicity of chromium in aquatic organisms. PMID:26995935

  12. Observations on Side-Swimming Rainbow Trout in Water Recirculation Aquaculture Systems

    PubMed Central

    Good, Christopher; Davidson, John; Kinman, Christin; Kenney, P. Brett; Bæverfjord, Grete; Summerfelt, Steven

    2014-01-01

    Abstract During a controlled 6-month study using six replicated water recirculation aquaculture systems (WRASs), it was observed that Rainbow Trout Oncorhynchus mykiss in all WRASs exhibited a higher-than-normal prevalence of side swimming (i.e., controlled, forward swimming but with misaligned orientation such that the fish's sagittal axis is approximately parallel to the horizontal plane). To further our understanding of this abnormality, a substudy was conducted wherein side swimmers and normally swimming fish were selectively sampled from each WRAS and growth performance (length, weight), processing attributes (fillet yield, visceral index, ventrum [i.e., thickness of the ventral “belly flap”] index), blood gas and chemistry parameters, and swim bladder morphology and positioning were compared. Side swimmers were found to be significantly smaller in length and weight and had less fillet yield but higher ventrum indices. Whole-blood analyses demonstrated that, among other things, side swimmers had significantly lower whole-blood pH and higher Pco 2. Side swimmers typically exhibited swim bladder malformations, although the positive predictive value of this subjective assessment was only 73%. Overall, this study found several anatomical and physiological differences between side-swimming and normally swimming Rainbow Trout. Given the reduced weight and fillet yield of market-age side swimmers, producers would benefit from additional research to reduce side-swimming prevalence in their fish stocks. Received March 20, 2014; accepted May 20, 2014 PMID:25250476

  13. A taste of the deep-sea: The roles of gustatory and tactile searching behaviour in the grenadier fish Coryphaenoides armatus

    NASA Astrophysics Data System (ADS)

    Bailey, David M.; Wagner, Hans-Joachim; Jamieson, Alan J.; Ross, Murray F.; Priede, Imants G.

    2007-01-01

    The deep-sea grenadier fishes ( Coryphaenoides spp.) are among the dominant predators and scavengers in the ocean basins that cover much of Earth's surface. Baited camera experiments were used to study the behaviour of these fishes. Despite the apparent advantages of rapidly consuming food, grenadiers attracted to bait spend a large proportion of their time in prolonged periods of non-feeding activity. Video analysis revealed that fish often adopted a head-down swimming attitude (mean of 21.3° between the fish and seafloor), with swimming velocity negatively related to attitude. The fish also swam around and along vertical and horizontal structures of the lander with their head immediately adjacent to the structure. We initially hypothesised that this behaviour was associated with the use of the short chin barbel in foraging. Barbel histology showed numerous taste buds in the skin, and a barbel nerve with about 20,000 axons in adult fish. A tracing experiment in one undamaged animal revealed the termination fields of the barbel neurons in the trigeminal and rhombencephalic regions, indicating both a mechanoreceptory and a gustatory role for the barbel. Our conclusion was that olfactory foraging becomes ineffective at close ranges and is followed by a search phase using tactile and gustatory sensing by the barbel. The development of this sensory method probably co-evolved alongside behavioural changes in swimming mechanics to allow postural stability at low swimming speeds.

  14. The Role of Stress Fibers in the Shape Determination Mechanism of Fish Keratocytes.

    PubMed

    Nakata, Takako; Okimura, Chika; Mizuno, Takafumi; Iwadate, Yoshiaki

    2016-01-19

    Crawling cells have characteristic shapes that are a function of their cell types. How their different shapes are determined is an interesting question. Fish epithelial keratocytes are an ideal material for investigating cell shape determination, because they maintain a nearly constant fan shape during their crawling locomotion. We compared the shape and related molecular mechanisms in keratocytes from different fish species to elucidate the key mechanisms that determine cell shape. Wide keratocytes from cichlids applied large traction forces at the rear due to large focal adhesions, and showed a spatially loose gradient associated with actin retrograde flow rate, whereas round keratocytes from black tetra applied low traction forces at the rear small focal adhesions and showed a spatially steep gradient of actin retrograde flow rate. Laser ablation of stress fibers (contractile fibers connected to rear focal adhesions) in wide keratocytes from cichlids increased the actin retrograde flow rate and led to slowed leading-edge extension near the ablated region. Thus, stress fibers might play an important role in the mechanism of maintaining cell shape by regulating the actin retrograde flow rate. PMID:26789770

  15. Effects of polar solvents on the mechanical behavior of fish scales.

    PubMed

    Murcia, Sandra; Li, Guihua; Yahyazadehfar, Mobin; Sasser, Mikaela; Ossa, Alex; Arola, D

    2016-04-01

    Fish scales are unique structural materials that serve as a form of natural armor. In this investigation the mechanical behavior of scales from the Cyprinus carpio was evaluated after exposure to a polar solvent. Uniaxial tensile and tear tests were conducted on specimens prepared from the scales of multiple fish extracted from near the head, middle and tail regions, and after exposure to ethanol for periods from 0 to 24h. Submersion in ethanol caused instantaneous changes in the tensile properties regardless of anatomical site, with increases in the elastic modulus, strength and modulus of toughness exceeding 100%. The largest increase in properties overall occurred in the elastic modulus of scales from the tail region and exceeded 200%. Although ethanol treatment had significant effect on the tensile properties, it had limited influence on the tear resistance. The contribution of ethanol to the mechanical behavior appears to be derived from an increase in the degree of interpeptide hydrogen-bonding of the collagen molecules. Spatial variations in the effects of ethanol exposure on the mechanical behavior arise from the differences in degree of mineralization and lower mineral content in scales of the tail region. PMID:26838819

  16. Relationships between metabolic rate, muscle electromyograms, and swim performance of adult chinook salmon

    SciTech Connect

    Geist, David R. ); Brown, Richard S. ); Cullinan, Valerie I. ); Mesa, Matthew G.; VanderKooi, S P.; McKinstry, Craig A. )

    2003-10-01

    We measured oxygen consumption rates of adult spring Chinook salmon and compared these values to other species of Pacific salmon. Our results indicated that adult salmon achieve their maximum level of oxygen consumption at about their upper critical swim speed. It is also at this speed that the majority of the energy supplied to the swimming fish switches from red muscle (powered by aerobic metabolism) to white muscle (powered by anaerobic metabolism). Determining the swimming performance of adult salmon will assist managers in developing fishways and other means to safely pass fish over hydroelectric dams and other man-made structures.

  17. Multi-directional thrusting using oppositely traveling waves in knifefish swimming

    NASA Astrophysics Data System (ADS)

    Curet, Oscar; Maciver, Malcolm; Patankar, Neelesh

    2009-11-01

    Apteronotus albifrons, also known as the black ghost knifefish, generate a weak electric field for omnidirectional sensing. This is matched by an extraordinary multi-directional swimming ability that is achieved by undulating a ribbon-like anal fin. Forward or backward motion is generated by a traveling wave on the ribbon fin. We have discovered that, for hovering and vertical swimming, the knifefish use two oppositely traveling waves on the ribbon fin. To understand the hydrodynamic mechanism of hovering and heave we performed fully resolved simulations of self-propulsion of the knifefish. We used kinematic inputs based on experimental observations. We found that the counter propagating waves generate two opposite streamwise jets along the bottom edge of the ribbon fin. These two jets meet approximately at the mid-section along the fin length and are deflected downward. The resultant downward momentum imparted to the fluid creates an upward force on the fish body which can be used for hovering or vertical swimming. There is a vortex ring pair of opposite directions at the middle of the fin that is associated with this fluid flow. Further insight into how the knifefish control heave and hovering was obtained from the measurements of force generated by a robotic ribbon fin for different wave parameters.

  18. Choreographed swimming of copepod nauplii.

    PubMed

    Lenz, Petra H; Takagi, Daisuke; Hartline, Daniel K

    2015-11-01

    Small metazoan paddlers, such as crustacean larvae (nauplii), are abundant, ecologically important and active swimmers, which depend on exploiting viscous forces for locomotion. The physics of micropaddling at low Reynolds number was investigated using a model of swimming based on slender-body theory for Stokes flow. Locomotion of nauplii of the copepod Bestiolina similis was quantified from high-speed video images to obtain precise measurements of appendage movements and the resulting displacement of the body. The kinematic and morphological data served as inputs to the model, which predicted the displacement in good agreement with observations. The results of interest did not depend sensitively on the parameters within the error of measurement. Model tests revealed that the commonly attributed mechanism of 'feathering' appendages during return strokes accounts for only part of the displacement. As important for effective paddling at low Reynolds number is the ability to generate a metachronal sequence of power strokes in combination with synchronous return strokes of appendages. The effect of feathering together with a synchronous return stroke is greater than the sum of each factor individually. The model serves as a foundation for future exploration of micropaddlers swimming at intermediate Reynolds number where both viscous and inertial forces are important. PMID:26490629

  19. Effect of inertia on laminar swimming and flying of an assembly of rigid spheres in an incompressible viscous fluid

    NASA Astrophysics Data System (ADS)

    Felderhof, B. U.

    2015-11-01

    A mechanical model of swimming and flying in an incompressible viscous fluid in the absence of gravity is studied on the basis of assumed equations of motion. The system is modeled as an assembly of rigid spheres subject to elastic direct interactions and to periodic actuating forces which sum to zero. Hydrodynamic interactions are taken into account in the virtual mass matrix and in the friction matrix of the assembly. An equation of motion is derived for the velocity of the geometric center of the assembly. The mean power is calculated as the mean rate of dissipation. The full range of viscosity is covered, so that the theory can be applied to the flying of birds, as well as to the swimming of fish or bacteria. As an example a system of three equal spheres moving along a common axis is studied.

  20. Effect of inertia on laminar swimming and flying of an assembly of rigid spheres in an incompressible viscous fluid.

    PubMed

    Felderhof, B U

    2015-11-01

    A mechanical model of swimming and flying in an incompressible viscous fluid in the absence of gravity is studied on the basis of assumed equations of motion. The system is modeled as an assembly of rigid spheres subject to elastic direct interactions and to periodic actuating forces which sum to zero. Hydrodynamic interactions are taken into account in the virtual mass matrix and in the friction matrix of the assembly. An equation of motion is derived for the velocity of the geometric center of the assembly. The mean power is calculated as the mean rate of dissipation. The full range of viscosity is covered, so that the theory can be applied to the flying of birds, as well as to the swimming of fish or bacteria. As an example a system of three equal spheres moving along a common axis is studied. PMID:26651783

  1. The fish tail motion forms an attached leading edge vortex

    PubMed Central

    Borazjani, Iman; Daghooghi, Mohsen

    2013-01-01

    The tail (caudal fin) is one of the most prominent characteristics of fishes, and the analysis of the flow pattern it creates is fundamental to understanding how its motion generates locomotor forces. A mechanism that is known to greatly enhance locomotor forces in insect and bird flight is the leading edge vortex (LEV) reattachment, i.e. a vortex (separation bubble) that stays attached at the leading edge of a wing. However, this mechanism has not been reported in fish-like swimming probably owing to the overemphasis on the trailing wake, and the fact that the flow does not separate along the body of undulating swimmers. We provide, to our knowledge, the first evidence of the vortex reattachment at the leading edge of the fish tail using three-dimensional high-resolution numerical simulations of self-propelled virtual swimmers with different tail shapes. We show that at Strouhal numbers (a measure of lateral velocity to the axial velocity) at which most fish swim in nature (approx. 0.25) an attached LEV is formed, whereas at a higher Strouhal number of approximately 0.6 the LEV does not reattach. We show that the evolution of the LEV drastically alters the pressure distribution on the tail and the force it generates. We also show that the tail's delta shape is not necessary for the LEV reattachment and fish-like kinematics is capable of stabilising the LEV. Our results suggest the need for a paradigm shift in fish-like swimming research to turn the focus from the trailing edge to the leading edge of the tail. PMID:23407826

  2. Kinematics and hydrodynamics of swimming in the mayfly larva.

    PubMed

    Brackenbury, John

    2004-02-01

    The kinematics and hydrodynamics of free-swimming mayfly larvae (Chloeon dipterum) were investigated with the aid of a simple wake visualisation technique (tracer dyes) and drag measurements on dead insects. The basic swimming movement consists of a high-amplitude dorso-ventral undulation and, during continuous swimming, this produces a wake of ring vortices shed alternately to the dorsal and ventral sides of the body. The ring vortices propagate laterally away from the body at an angle of approximately 80 degrees relative to dead aft of the swimming line. Thus, mayfly larvae, like damsel-fly larvae, resemble eels in producing a wake consisting of separate vortices that propagate laterally rather than the reverse von Karman vortex street characteristic of most caudal fin swimming fish. The thrust estimated from the momentum in the wake of swimming mayfly larvae was comparable with the drag measured on dead specimens. Possible sources of error in these estimates are discussed, but the conclusion is reached that even though only 14% of the total force generated by vortex production is directed forwards, it is still sufficient to account for the thrust required for steady locomotion. PMID:14766950

  3. Microstructure, mechanical, and biomimetic properties of fish scales from Pagrus major.

    PubMed

    Ikoma, Toshiyuki; Kobayashi, Hisatoshi; Tanaka, Junzo; Walsh, Dominic; Mann, Stephen

    2003-06-01

    The fish scale of Pagrus major has an orthogonal plywood structure of stratified lamellae, 1-2 microm in thickness, consisting of closely packed 70- to 80-nm-diameter collagen fibers. X-ray diffraction, energy-dispersive X-ray analysis, and infrared spectroscopy indicate that the mineral phase in the scale is calcium-deficient hydroxyapatite containing a small amount of sodium and magnesium ions, as well as carbonate anions in phosphate sites of the apatite lattice. The tensile strength of the scale is high (approximately 90 MPa) because of the hierarchically ordered structure of mineralized collagen fibers. Mechanical failure occurs by sliding of the lamellae and associated pulling out and fracture of the collagen fibers. In contrast, demineralized scales have significantly lower tensile strength (36 MPa), indicating that interactions between the apatite crystals and collagen fibers are of fundamental importance in determining the mechanical properties. Thermal treatment of fish scales to remove the organic components produces remarkable inorganic replicas of the native orthogonal plywood structure of the fibrillary plate. The biomimetic replica produced by heating to 873 K consists of stratified porous lamellae of c-axis-aligned apatite crystals that are long, narrow plates, 0.5-0.6 microm in length and 0.1-0.2 microm in width. The textured inorganic material remains intact when heated to 1473 K, although the size of the constituent crystals increases as a result of thermal sintering. PMID:12781659

  4. Burst Firing in the Electrosensory System of Gymnotiform Weakly Electric Fish: Mechanisms and Functional Roles

    PubMed Central

    Metzen, Michael G.; Krahe, Rüdiger; Chacron, Maurice J.

    2016-01-01

    Neurons across sensory systems and organisms often display complex patterns of action potentials in response to sensory input. One example of such a pattern is the tendency of neurons to fire packets of action potentials (i.e., a burst) followed by quiescence. While it is well known that multiple mechanisms can generate bursts of action potentials at both the single-neuron and the network level, the functional role of burst firing in sensory processing is not so well understood to date. Here we provide a comprehensive review of the known mechanisms and functions of burst firing in processing of electrosensory stimuli in gymnotiform weakly electric fish. We also present new evidence from existing data showing that bursts and isolated spikes provide distinct information about stimulus variance. It is likely that these functional roles will be generally applicable to other systems and species. PMID:27531978

  5. Comparative study on nano-mechanics and thermodynamics of fish otoliths.

    PubMed

    Dongni, Ren; Yonghua, Gao; Qingling, Feng

    2013-01-01

    Fish otolith is a kind of typical natural biomineral, which is composed of calcium carbonate and organic matrix. In fresh water carp otolith, the inorganic phase of lapillus is pure aragonite, and for asteriscus it is pure vaterite. In this research, the phase composition, phase transformation, mechanical property and solubility of lapillus and asteriscus were studied. And results showed that, the organic content of lapillus was higher than that of asteriscus; the phase-transition temperature of lapillus (aragonite-calcite) and asteriscus (vaterite-calcite) both happened between 520 and 640 °C; the nano-mechanical property of lapillus was better than that of asteriscus; the solubility of asteriscus powder was higher than that of lapillus powder. PMID:25428035

  6. Influence of externally attached trasmitters on the swimming performance of juvenile white sturgeon

    USGS Publications Warehouse

    Counihan, T.D.; Frost, C.N.

    1999-01-01

    We measured the critical swimming speed of juvenile white sturgeons Acipenser transmontanus equipped with externally attached dummy ultrasonic transmitters and of untagged control fish in the laboratory. White sturgeons ranging from 31.9 to 37.0 cm fork length were subjected to one of three treatments: Control (handled but not tagged), tag attached below the dorsal fin, and tag attached with the anterior insertion point between the fourth and fifth dorsal scutes. Although transmitters were of recommended weight, we found that the swimming performance of tagged white sturgeons was significantly less than that of untagged control fish. Swimming performance of tagged fish was not differentially affected by tag location. Our results suggest that data from ultrasonic telemetry studies of externally tagged juvenile white sturgeons should be interpreted with caution due to the reduced swimming performance caused by external transmitters.

  7. Influence of externally attached transmitters on the swimming performance of juvenile white sturgeon

    USGS Publications Warehouse

    Counihan, T.D.; Frost, C.N.

    1999-01-01

    We measured the critical swimming speed of juvenile white sturgeons Acipenser transmontanus equipped with externally attached dummy ultrasonic transmitters and of untagged control fish in the laboratory. White sturgeons ranging from 31.9 to 37.0 cm fork length were subjected to one of three treatments: control (handled but not tagged), tag attached below the dorsal fin, and tag attached with the anterior insertion point between the fourth and fifth dorsal scutes. Although transmitters were of recommended weight, we found that the swimming performance of tagged white sturgeons was significantly less than that of untagged control fish. Swimming performance of tagged fish was not differentially affected by tag location. Our results suggest that data from ultrasonic telemetry studies of externally tagged juvenile white sturgeons should be interpreted with caution due to the reduced swimming performance caused by external transmitters.

  8. Warm Water and Cool Nests Are Best. How Global Warming Might Influence Hatchling Green Turtle Swimming Performance

    PubMed Central

    Booth, David T.; Evans, Andrew

    2011-01-01

    For sea turtles nesting on beaches surrounded by coral reefs, the most important element of hatchling recruitment is escaping predation by fish as they swim across the fringing reef, and as a consequence hatchlings that minimize their exposure to fish predation by minimizing the time spent crossing the fringing reef have a greater chance of surviving the reef crossing. One way to decrease the time required to cross the fringing reef is to maximize swimming speed. We found that both water temperature and nest temperature influence swimming performance of hatchling green turtles, but in opposite directions. Warm water increases swimming ability, with hatchling turtles swimming in warm water having a faster stroke rate, while an increase in nest temperature decreases swimming ability with hatchlings from warm nests producing less thrust per stroke. PMID:21826236

  9. The swimming of animalcules

    NASA Astrophysics Data System (ADS)

    Felderhof, B. U.

    2006-06-01

    Animalcules can swim in a viscous fluid at low Reynolds number and low Stokes number by moving their body parts in a periodic coherent fashion. The swimming motion is analyzed in a simple model of beads subject to periodic one-body forces. In the model the animalcule is held together by reactive two-body forces. The nonlinear equations of Stokesian dynamics are formulated on the basis of the Oseen tensor. Under suitable conditions the solution of the equations of motion has a limit cycle character. The limit cycle is analyzed for small amplitude motion in the framework of a bilinear theory. The linearized equations of motion are solved analytically for longitudinal and transverse modes of motion for a linear trimer, and expressions are derived for the swimming velocity and the mean dissipation to second order in the force amplitude. The results of the bilinear theory are compared to numerical solution of the nonlinear equations of motion. A similar comparison is made for chains of twelve beads.

  10. Hydrodynamics of Fishlike Swimming: Effects of swimming kinematics and Reynolds number

    NASA Astrophysics Data System (ADS)

    Gilmanov, Anvar; Posada, Nicolas; Sotiropoulos, Fotis

    2003-11-01

    We carry out a series of numerical simulations to investigate the effects of swimming kinematics and Reynolds number on the flow past a three-dimensional fishlike body undergoing undulatory motion. The simulated body shape is that of a real mackerel fish. The mackerel was frozen and subsequently sliced in several thin fillets whose dimensions were carefully measured and used to construct the fishlike body shape used in the simulations. The flow induced by the undulating body is simulated by solving the 3D, unsteady, incompressible Navier-Stokes equations with the second-order accurate, hybrid Cartesian/Immersed Boundary formulation of Gilmanov and Sotiropoulos (J. Comp. Physics, under review, 2003). We consider in-line swimming at constant speed and carry out simulations for various types of swimming kinematics, varying the tailbeat amplitude, frequency, and Reynolds number (300fish wake and the role of these vortices on drag reduction, thrust procuction, and propulsive efficiency.

  11. Relationships between metabolic rate, muscle electromyograms and swim performance of adult chinook salmon

    USGS Publications Warehouse

    Geist, D.R.; Brown, R.S.; Cullinan, V.I.; Mesa, M.G.; VanderKooi, S.P.; McKinstry, C.A.

    2003-01-01

    Oxygen consumption rates of adult spring chinook salmon Oncorhynchus tshawytscha increased with swim speed and, depending on temperature and fish mass, ranged from 609 mg O2 h-1 at 30 cm s-1 (c. 0.5 BLs-1) to 3347 mg O2 h-1 at 170 cm s -1 (c. 2.3 BLs-1). Corrected for fish mass, these values ranged from 122 to 670 mg O2 kg-1 h-1, and were similar to other Oncorhynchus species. At all temperatures (8, 12.5 and 17??C), maximum oxygen consumption values levelled off and slightly declined with increasing swim speed >170 cm s-1, and a third-order polynomial regression model fitted the data best. The upper critical swim speed (Ucrit) of fish tested at two laboratories averaged 155 cm s -1 (2.1 BLs-1), but Ucrit of fish tested at the Pacific Northwest National Laboratory were significantly higher (mean 165 cm s-1) than those from fish tested at the Columbia River Research Laboratory (mean 140 cm s-1). Swim trials using fish that had electromyogram (EMG) transmitters implanted in them suggested that at a swim speed of c. 135 cm s-1, red muscle EMG pulse rates slowed and white muscle EMG pulse rates increased. Although there was significant variation between individual fish, this swim speed was c. 80% of the Ucrit for the fish used in the EMG trials (mean Ucrit 168.2 cm s-1). Bioenergetic modelling of the upstream migration of adult chinook salmon should consider incorporating an anaerobic fraction of the energy budget when swim speeds are ???80% of the Ucrit. ?? 2003 The Fisheries Society of the British Isles.

  12. Sprint swimming performance of wild bull trout (Salvelinus confluentus)

    USGS Publications Warehouse

    Mesa, M.G.; Phelps, J.; Weiland, L.K.

    2008-01-01

    We conducted laboratory experiments to determine the sprint swimming performance of wild juvenile and adult bull trout Salvelinus confluentus. Sprint swimming speeds were estimated using high-speed digital video analysis. Thirty two bull trout were tested in sizes ranging from about 10 to 31 cm. Of these, 14 fish showed at least one motivated, vigorous sprint. When plotted as a function of time, velocity of fish increased rapidly with the relation linear or slightly curvilinear. Their maximum velocity, or Vmax, ranged from 1.3 to 2.3 m/s, was usually achieved within 0.8 to 1.0 s, and was independent of fish size. Distances covered during these sprints ranged from 1.4 to 2.4 m. Our estimates of the sprint swimming performance are the first reported for this species and may be useful for producing or modifying fish passage structures that allow safe and effective passage of fish without overly exhausting them. ?? 2008 by the Northwest Scientific Association. All rights reserved.

  13. A kinematic and dynamic comparison of surface and underwater displacement in high level monofin swimming.

    PubMed

    Nicolas, Guillaume; Bideau, Benoit

    2009-08-01

    Fin swimming performance can be divided into underwater and surface water races. World records are about 10% faster for underwater swimming vs. surface swimming, but little is known about the advantage of underwater swimming for monofin swimming. Some authors reported that the air-water interface influences the kinematics and leads to a narrow vertical amplitude of the fin. On the one hand, surface swimming is expected to affect drag parameters (cross-sectional area (S) and active drag (AD)) when compared to underwater swimming. On the other hand, the surface swimming technique may also affect efficiency (eta(F)). The aim of this study is therefore to evaluate and compare drag parameters and efficiency during underwater and surface swimming. To this end, 12 international level monofin swimmers were measured during both underwater and surface swimming. Kinematic parameters (both dimensional and non-dimensional), eta(F) (calculated according to the Elongated-Body Theory), and AD (computed with Velocity Perturbation Method) were calculated for an underwater and a surface fin swimming trial, performed at maximal speed. As expected, results showed significantly lower velocities during surface swimming vs. underwater V(1,under) =2.5ms(-1) vs. V(1,surf) =2.36ms(-1), p<.01). Velocities during underwater and surface swimming were strongly correlated (r=.97, p<.01). Underwater swimming was also associated with higher vertical amplitudes of the fin compared to surface swimming (V(under) =0.55mvs. V(surf) )=0.46m, p<.01). Length-specific amplitudes (A(under)/L(b)) were in the order of 20% during underwater swimming as for undulating fish, and significantly higher than during surface swimming (A(surf)/L(b)=17%, p<.01). Efficiency for surface swimming was about 6% lower than for underwater swimming (eta(F,under) =0.79 vs. eta(F,surf) =0.74, p<.01). This decrease could be associated with an increase in swimming frequency for surface swimming (f (surf)=2.15Hz vs. f (under)=2.08Hz

  14. Evaluation of Fish-Injury Mechanisms During Exposure to Turbulent Shear Flow

    SciTech Connect

    Deng, Zhiqun; Guensch, Greg R.; McKinstry, Craig A.; Mueller, Robert P.; Dauble, Dennis D.; Richmond, Marshall C.

    2005-07-22

    Motion tracking analysis was performed on high-speed, high-resolution digital videos of juvenile salmonids exposed to a laboratory-generated shear environment to isolate injury mechanisms. Hatchery-reared fall chinook salmon (93-128 mm in length) were introduced into the top portion of a submerged, 6.35-cm diameter water jet at velocities ranging from 12.2 to 19.8 m•s-1, with a control group released at 3 m•s-1. Injuries typical of turbine passed fish, including eye damage, opercle damage, bruising, loss of equilibrium, lethargy, and mortality were observed and recorded. Three-dimensional trajectories were generated for four locations (nose, head, centroid, tail) on each fish released. Time series of velocity, acceleration, force, jerk, and bending angle were computed from the 3-dimensional trajectories of the centroid using finite-difference methods. The onset of minor, major and fatal injuries occurred at nozzle velocities of 12.2 13.7 and 16.8 m•s-1, respectively, corresponding to exposure strain rates of 683, 761, and 933 s-1. Opercle injuries occurred at 12.2 m•s-1 nozzle velocity, while eye injuries, bruising, and loss of equilibrium were common at speeds of 16.8 m•s-1 and above. Of the computed dynamic parameters, acceleration showed the strongest predictive power for eye and opercle injuries and overall injury level, and it may provide the best potential link between laboratory studies of fish injury, field studies designed to collect similar data in situ, and computational fluid dynamics (CFD) model output.

  15. Swimming bacteria power microscopic gears

    PubMed Central

    Sokolov, Andrey; Apodaca, Mario M.; Grzybowski, Bartosz A.; Aranson, Igor S.

    2010-01-01

    Whereas the laws of thermodynamics prohibit extraction of useful work from the Brownian motion of particles in equilibrium, these motions can be “rectified” under nonequilibrium conditions, for example, in the presence of asymmetric geometrical obstacles. Here, we describe a class of systems in which aerobic bacteria Bacillus subtilis moving randomly in a fluid film power submillimeter gears and primitive systems of gears decorated with asymmetric teeth. The directional rotation is observed only in the regime of collective bacterial swimming and the gears’ angular velocities depend on and can be controlled by the amount of oxygen available to the bacteria. The ability to harness and control the power of collective motions appears an important requirement for further development of mechanical systems driven by microorganisms. PMID:20080560

  16. Swimming bacteria power microscopic gears

    SciTech Connect

    Sokolov, Andrey; Apodaca, Mario M.; Grzybowski, Bartosz A.; Aranson, Igor S.

    2010-01-19

    Whereas the laws of thermodynamics prohibit extraction of useful work from the Brownian motion of particles in equilibrium, these motions can be “rectified” under nonequilibrium conditions, for example, in the presence of asymmetric geometrical obstacles. Here, we describe a class of systems in which aerobic bacteria Bacillus subtilis moving randomly in a fluid film power submillimeter gears and primitive systems of gears decorated with asymmetric teeth. The directional rotation is observed only in the regime of collective bacterial swimming and the gears’ angular velocities depend on and can be controlled by the amount of oxygen available to the bacteria. The ability to harness and control the power of collective motions appears an important requirement for further development of mechanical systems driven by microorganisms.

  17. Swimming bacteria power microscopic gears.

    SciTech Connect

    Sokolov, A.; Apodaca, M. M.; Grzybowski, B. A.; Aranson, I. S.; Materials Science Division; Princeton Univ.; Northwestern Univ.

    2010-01-19

    Whereas the laws of thermodynamics prohibit extraction of useful work from the Brownian motion of particles in equilibrium, these motions can be 'rectified' under nonequilibrium conditions, for example, in the presence of asymmetric geometrical obstacles. Here, we describe a class of systems in which aerobic bacteria Bacillus subtilis moving randomly in a fluid film power submillimeter gears and primitive systems of gears decorated with asymmetric teeth. The directional rotation is observed only in the regime of collective bacterial swimming and the gears angular velocities depend on and can be controlled by the amount of oxygen available to the bacteria. The ability to harness and control the power of collective motions appears an important requirement for further development of mechanical systems driven by microorganisms.

  18. Swimming overuse injuries associated with triathlon training.

    PubMed

    Bales, James; Bales, Karrn

    2012-12-01

    Most triathlon overuse injuries occur due to the running and cycling aspects of the sport. By nature of swimming being a non-weight-bearing sport, triathletes have a tendency to use swimming for rehabilitation and recovery. Swimming has a significantly lower injury rate than the other 2 disciplines in a triathlon. Most triathletes use the freestyle stroke, because it is typically the first stroke learned, it is for many the fastest stroke, and by lifting the head the freestyle stroke allows triathletes to sight their direction, which is important in open water swimming. During the freestyle stroke, the shoulder undergoes repetitive overhead motion, and shoulder pain is the most common and well-documented site of musculoskeletal pain in competitive swimmers. It is felt that the pathologic process is attributable to repetitive overhead motion causing microtrauma in the shoulder from either mechanical impingement or generalized laxity or both. Without sufficient rest and recovery, the development of inflammation and pain may result. Depending on the age of the triathlete and the exact etiology of the shoulder pain, treatment options range from nonsurgical to surgical in nature. PMID:23147088

  19. Controlled-frequency breath swimming improves swimming performance and running economy.

    PubMed

    Lavin, K M; Guenette, J A; Smoliga, J M; Zavorsky, G S

    2015-02-01

    Respiratory muscle fatigue can negatively impact athletic performance, but swimming has beneficial effects on the respiratory system and may reduce susceptibility to fatigue. Limiting breath frequency during swimming further stresses the respiratory system through hypercapnia and mechanical loading and may lead to appreciable improvements in respiratory muscle strength. This study assessed the effects of controlled-frequency breath (CFB) swimming on pulmonary function. Eighteen subjects (10 men), average (standard deviation) age 25 (6) years, body mass index 24.4 (3.7) kg/m(2), underwent baseline testing to assess pulmonary function, running economy, aerobic capacity, and swimming performance. Subjects were then randomized to either CFB or stroke-matched (SM) condition. Subjects completed 12 training sessions, in which CFB subjects took two breaths per length and SM subjects took seven. Post-training, maximum expiratory pressure improved by 11% (15) for all 18 subjects (P < 0.05) while maximum inspiratory pressure was unchanged. Running economy improved by 6 (9)% in CFB following training (P < 0.05). Forced vital capacity increased by 4% (4) in SM (P < 0.05) and was unchanged in CFB. These findings suggest that limiting breath frequency during swimming may improve muscular oxygen utilization during terrestrial exercise in novice swimmers. PMID:24151982

  20. Evolutionary multiobjective design of a flexible caudal fin for robotic fish.

    PubMed

    Clark, Anthony J; Tan, Xiaobo; McKinley, Philip K

    2015-12-01

    Robotic fish accomplish swimming by deforming their bodies or other fin-like appendages. As an emerging class of embedded computing system, robotic fish are anticipated to play an important role in environmental monitoring, inspection of underwater structures, tracking of hazardous wastes and oil spills, and the study of live fish behaviors. While integration of flexible materials (into the fins and/or body) holds the promise of improved swimming performance (in terms of both speed and maneuverability) for these robots, such components also introduce significant design challenges due to the complex material mechanics and hydrodynamic interactions. The problem is further exacerbated by the need for the robots to meet multiple objectives (e.g., both speed and energy efficiency). In this paper, we propose an evolutionary multiobjective optimization approach to the design and control of a robotic fish with a flexible caudal fin. Specifically, we use the NSGA-II algorithm to investigate morphological and control parameter values that optimize swimming speed and power usage. Several evolved fin designs are validated experimentally with a small robotic fish, where fins of different stiffness values and sizes are printed with a multi-material 3D printer. Experimental results confirm the effectiveness of the proposed design approach in balancing the two competing objectives. PMID:26601975

  1. Neuromolecular responses to social challenge: common mechanisms across mouse, stickleback fish, and honey bee.

    PubMed

    Rittschof, Clare C; Bukhari, Syed Abbas; Sloofman, Laura G; Troy, Joseph M; Caetano-Anollés, Derek; Cash-Ahmed, Amy; Kent, Molly; Lu, Xiaochen; Sanogo, Yibayiri O; Weisner, Patricia A; Zhang, Huimin; Bell, Alison M; Ma, Jian; Sinha, Saurabh; Robinson, Gene E; Stubbs, Lisa

    2014-12-16

    Certain complex phenotypes appear repeatedly across diverse species due to processes of evolutionary conservation and convergence. In some contexts like developmental body patterning, there is increased appreciation that common molecular mechanisms underlie common phenotypes; these molecular mechanisms include highly conserved genes and networks that may be modified by lineage-specific mutations. However, the existence of deeply conserved mechanisms for social behaviors has not yet been demonstrated. We used a comparative genomics approach to determine whether shared neuromolecular mechanisms could underlie behavioral response to territory intrusion across species spanning a broad phylogenetic range: house mouse (Mus musculus), stickleback fish (Gasterosteus aculeatus), and honey bee (Apis mellifera). Territory intrusion modulated similar brain functional processes in each species, including those associated with hormone-mediated signal transduction and neurodevelopment. Changes in chromosome organization and energy metabolism appear to be core, conserved processes involved in the response to territory intrusion. We also found that several homologous transcription factors that are typically associated with neural development were modulated across all three species, suggesting that shared neuronal effects may involve transcriptional cascades of evolutionarily conserved genes. Furthermore, immunohistochemical analyses of a subset of these transcription factors in mouse again implicated modulation of energy metabolism in the behavioral response. These results provide support for conserved genetic "toolkits" that are used in independent evolutions of the response to social challenge in diverse taxa. PMID:25453090

  2. Ontogeny, morphology and mechanics of the tessellated skeleton of cartilaginous fishes

    NASA Astrophysics Data System (ADS)

    Dean, Mason N.

    2009-12-01

    The members of the successful and diverse lineage of elasmobranch fishes (sharks, rays and relatives) possess endoskeletons fashioned entirely of cartilage. This is counterintuitive because cartilage, unlike bone, lacks a major blood supply and has limited capacity for repair; yet these fishes exhibit particularly dynamic lifestyles and high levels of performance. The functionality of this skeletal tissue is likely due to its mineralization: in most skeletal elements, the soft cartilage core is tiled (tessellated) with an outer rind of abutting hydroxyapatite blocks called tesserae, joined together by intertesseral fibers and overlain by the fibrous perichondrium. This basic composite arrangement of tissues has been appreciated for over a century, but available techniques have limited the ability to examine elasmobranch cartilage adequately---without artifacts, in 3-dimensions and at high resolution---so that its development, mechanics and phylogeny might be contextualized among vertebrate skeletal tissues. I summarize the history, nomenclature and challenges relating to study of tessellated cartilage (Chapter 1) and present a low temperature microscopy technique to facilitate visualization of all tissue components in situ (Chapter 2). I use that technique in tandem with synchrotron microtomography to examine the ultrastructure of tesserae (Chapter 3) and the development of tessellated cartilage across ontogeny (Chapter 4). Finally, I examine the ways in which selection acts on skeletal morphology by examining cranial anatomy across 40 species of batoid fishes (rays and relatives) in the contexts of ecology and phylogeny (Chapter 5). There are some similarities between mineralizing bone and elasmobranch cartilage (e.g. the flattening of peripheral cells in the unmineralized phase, decreases in cellular density with mineralization, the presence of canaliculi connecting entombed cells). However, the ability for tessellated cartilage to grow (through enlargement of

  3. Colour variation in cichlid fish: Developmental mechanisms, selective pressures and evolutionary consequences☆

    PubMed Central

    Maan, Martine E.; Sefc, Kristina M.

    2013-01-01

    Cichlid fishes constitute one of the most species-rich families of vertebrates. In addition to complex social behaviour and morphological versatility, they are characterised by extensive diversity in colouration, both within and between species. Here, we review the cellular and molecular mechanisms underlying colour variation in this group and the selective pressures responsible for the observed variation. We specifically address the evidence for the hypothesis that divergence in colouration is associated with the evolution of reproductive isolation between lineages. While we conclude that cichlid colours are excellent models for understanding the role of animal communication in species divergence, we also identify taxonomic and methodological biases in the current research effort. We suggest that the integration of genomic approaches with ecological and behavioural studies, across the entire cichlid family and beyond it, will contribute to the utility of the cichlid model system for understanding the evolution of biological diversity. PMID:23665150

  4. Modular microrobot for swimming in heterogeneous environments

    NASA Astrophysics Data System (ADS)

    Cheang, U. Kei; Meshkati, Meshkati; Fu, Henry; Kim, Minjun; Drexel University Team; University of Nevada, Reno Team

    2015-11-01

    One of the difficulties in navigating in vivo is to overcome many types of environments. This includes blood vessels of different diameters, fluids with different mechanical properties, and physical barriers. Inspired by conventional modular robotics, we demonstrate modular microrobotics using magnetic particles as the modular units to change size and shape through docking and undocking. Much like the vast variety of microorganisms navigating many different bio-environments, modular microswimmers have the ability to dynamically adapt different environments by reconfiguring the swimmers' physical characteristics. We model the docking as magnetic assembly and undocking mechanisms as deformation by hydrodynamic forces. We characterize the swimming capability of the modular microswimmer with different size and shapes. Finally, we demonstrate modular microrobotics by assembling a three-bead microswimmer into a nine-bead microswimmer, and then disassemble it into several independently swimming microswimmers..

  5. Numerical simulations of undulatory swimming at moderate Reynolds number.

    PubMed

    Eldredge, Jeff D

    2006-12-01

    We perform numerical simulations of the swimming of a three-linkage articulated system in a moderately viscous regime. The computational methodology focuses on the creation, diffusion and transport of vorticity from the surface of the bodies into the fluid. The simulations are dynamically coupled, in that the motion of the three-linkage swimmer is computed simultaneously with the dynamics of the fluid. The novel coupling scheme presented in this work is the first to exploit the relationship between vorticity creation and body dynamics. The locomotion of the system, when subject to undulatory inputs of the hinges, is computed at Reynolds numbers of 200 and 1000. It is found that the forward swimming speed increases with the Reynolds number, and that in both cases the swimming is slower than in an inviscid medium. The vortex shedding is examined, and found to exhibit behavior consistent with experimental flow visualizations of fish. PMID:17671314

  6. Disease resistance is related to inherent swimming performance in Atlantic salmon

    PubMed Central

    2013-01-01

    Background Like humans, fish can be classified according to their athletic performance. Sustained exercise training of fish can improve growth and physical capacity, and recent results have documented improved disease resistance in exercised Atlantic salmon. In this study we investigated the effects of inherent swimming performance and exercise training on disease resistance in Atlantic salmon. Atlantic salmon were first classified as either poor or good according to their swimming performance in a screening test and then exercise trained for 10 weeks using one of two constant-velocity or two interval-velocity training regimes for comparison against control trained fish (low speed continuously). Disease resistance was assessed by a viral disease challenge test (infectious pancreatic necrosis) and gene expression analyses of the host response in selected organs. Results An inherently good swimming performance was associated with improved disease resistance, as good swimmers showed significantly better survival compared to poor swimmers in the viral challenge test. Differences in mortalities between poor and good swimmers were correlated with cardiac mRNA expression of virus responsive genes reflecting the infection status. Although not significant, fish trained at constant-velocity showed a trend towards higher survival than fish trained at either short or long intervals. Finally, only constant training at high intensity had a significant positive effect on fish growth compared to control trained fish. Conclusions This is the first evidence suggesting that inherent swimming performance is associated with disease resistance in fish. PMID:23336751

  7. Bio-inspired flexible joints with passive feathering for robotic fish pectoral fins.

    PubMed

    Behbahani, Sanaz Bazaz; Tan, Xiaobo

    2016-06-01

    In this paper a novel flexible joint is proposed for robotic fish pectoral fins, which enables a swimming behavior emulating the fin motions of many aquatic animals. In particular, the pectoral fin operates primarily in the rowing mode, while undergoing passive feathering during the recovery stroke to reduce hydrodynamic drag on the fin. The latter enables effective locomotion even with symmetric base actuation during power and recovery strokes. A dynamic model is developed to facilitate the understanding and design of the joint, where blade element theory is used to calculate the hydrodynamic forces on the pectoral fins, and the joint is modeled as a paired torsion spring and damper. Experimental results on a robotic fish prototype are presented to illustrate the effectiveness of the joint mechanism, validate the proposed model, and indicate the utility of the proposed model for the optimal design of joint depth and stiffness in achieving the trade-off between swimming speed and mechanical efficiency. PMID:27144946

  8. Swimming of a Microrobot Actuated by a Clinical Magnetic Resonance Imaging Apparatus

    NASA Astrophysics Data System (ADS)

    Gosselin, Frederck P.; Zhou, David; Lalande, Viviane; Vonthron, Manuel; Martel, Sylvain

    2010-11-01

    A miniature robot was designed to achieve fish-like locomotion when actuated by the imaging coils of a clinical Magnetic Resonance Imaging (MRI) system. The wireless fish robot is composed of a ferromagnetic head, a flexible tail and a float. In an aquarium placed in the MRI, the robot is set into a swimming motion by an alternating transverse linear magnetic gradient. The influence of tail length, forcing frequency and forcing magnitude on the swimming velocity and flapping amplitude are investigated. Moreover, by using a combination of simultaneous magnetic gradients, the fish can reach superior swimming speeds than can be achieved by simply "pulling" on the fish with a magnetic field. Upon further miniaturization, the propulsion principle devised here could be used to navigate a micro surgical robot or a drug delivery system. A great advantage of this system is that no energy storage, motor or control system need to be carried by the robot, allowing great miniaturization possibilities.

  9. Mechanisms of animal diapause: recent developments from nematodes, crustaceans, insects, and fish.

    PubMed

    Hand, Steven C; Denlinger, David L; Podrabsky, Jason E; Roy, Richard

    2016-06-01

    Life cycle delays are beneficial for opportunistic species encountering suboptimal environments. Many animals display a programmed arrest of development (diapause) at some stage(s) of their development, and the diapause state may or may not be associated with some degree of metabolic depression. In this review, we will evaluate current advancements in our understanding of the mechanisms responsible for the remarkable phenotype, as well as environmental cues that signal entry and termination of the state. The developmental stage at which diapause occurs dictates and constrains the mechanisms governing diapause. Considerable progress has been made in clarifying proximal mechanisms of metabolic arrest and the signaling pathways like insulin/Foxo that control gene expression patterns. Overlapping themes are also seen in mechanisms that control cell cycle arrest. Evidence is emerging for epigenetic contributions to diapause regulation via small RNAs in nematodes, crustaceans, insects, and fish. Knockdown of circadian clock genes in selected insect species supports the importance of clock genes in the photoperiodic response that cues diapause. A large suite of chaperone-like proteins, expressed during diapause, protects biological structures during long periods of energy-limited stasis. More information is needed to paint a complete picture of how environmental cues are coupled to the signal transduction that initiates the complex diapause phenotype, as well as molecular explanations for how the state is terminated. Excellent examples of molecular memory in post-dauer animals have been documented in Caenorhabditis elegans It is clear that a single suite of mechanisms does not regulate diapause across all species and developmental stages. PMID:27053646

  10. Paramecia swimming in viscous flow

    NASA Astrophysics Data System (ADS)

    Zhang, P.; Jana, S.; Giarra, M.; Vlachos, P. P.; Jung, S.

    2015-12-01

    Ciliates like Paramecia exhibit fore-aft asymmetry in their body shapes, and preferentially swim in the direction of the slender anterior rather than the wider posterior. However, the physical reasons for this preference are not well understood. In this work, we propose that specific features of the fluid flow around swimming Paramecia confer some energetic advantage to the preferred swimming direction. Therefore, we seek to understand the effects of body asymmetry and swimming direction on the efficiency of swimming and the flux of fluid into the cilia layer (and thus of food into the oral groove), which we assumed to be primary factors in the energy budgets of these organisms. To this end, we combined numerical techniques (the boundary element method) and laboratory experiments (micro particle image velocimetry) to develop a quantitative model of the flow around a Paramecium and investigate the effect of the body shape on the velocity fields, as well as on the swimming and feeding behaviors. Both simulation and experimental results show that velocity fields exhibit fore-aft asymmetry. Moreover, the shape asymmetry revealed an increase of the fluid flux into the cilia layer compared to symmetric body shapes. Under the assumption that cilia fluid intake and feeding efficiency are primary factors in the energy budgets of Paramecia, our model predicts that the anterior swimming direction is energetically favorable to the posterior swimming direction.

  11. Fish locomotion: recent advances and new directions.

    PubMed

    Lauder, George V

    2015-01-01

    Research on fish locomotion has expanded greatly in recent years as new approaches have been brought to bear on a classical field of study. Detailed analyses of patterns of body and fin motion and the effects of these movements on water flow patterns have helped scientists understand the causes and effects of hydrodynamic patterns produced by swimming fish. Recent developments include the study of the center-of-mass motion of swimming fish and the use of volumetric imaging systems that allow three-dimensional instantaneous snapshots of wake flow patterns. The large numbers of swimming fish in the oceans and the vorticity present in fin and body wakes support the hypothesis that fish contribute significantly to the mixing of ocean waters. New developments in fish robotics have enhanced understanding of the physical principles underlying aquatic propulsion and allowed intriguing biological features, such as the structure of shark skin, to be studied in detail. PMID:25251278

  12. Fish Locomotion: Recent Advances and New Directions

    NASA Astrophysics Data System (ADS)

    Lauder, George V.

    2015-01-01

    Research on fish locomotion has expanded greatly in recent years as new approaches have been brought to bear on a classical field of study. Detailed analyses of patterns of body and fin motion and the effects of these movements on water flow patterns have helped scientists understand the causes and effects of hydrodynamic patterns produced by swimming fish. Recent developments include the study of the center-of-mass motion of swimming fish and the use of volumetric imaging systems that allow three-dimensional instantaneous snapshots of wake flow patterns. The large numbers of swimming fish in the oceans and the vorticity present in fin and body wakes support the hypothesis that fish contribute significantly to the mixing of ocean waters. New developments in fish robotics have enhanced understanding of the physical principles underlying aquatic propulsion and allowed intriguing biological features, such as the structure of shark skin, to be studied in detail.

  13. Eating without hands or tongue: specialization, elaboration and the evolution of prey processing mechanisms in cartilaginous fishes

    PubMed Central

    Dean, Mason N; Wilga, Cheryl D; Summers, Adam P

    2005-01-01

    The ability to separate edible from inedible portions of prey is integral to feeding. However, this is typically overlooked in favour of prey capture as a driving force in the evolution of vertebrate feeding mechanisms. In processing prey, cartilaginous fishes appear handicapped because they lack the pharyngeal jaws of most bony fishes and the muscular tongue and forelimbs of most tetrapods. We argue that the elaborate cranial muscles of some cartilaginous fishes allow complex prey processing in addition to their usual roles in prey capture. The ability to manipulate prey has evolved twice along different mechanical pathways. Batoid chondrichthyans (rays and relatives) use elaborate lower jaw muscles to process armored benthic prey, separating out energetically useless material. In contrast, megacarnivorous carcharhiniform and lamniform sharks use a diversity of upper jaw muscles to control the jaws while gouging, allowing for reduction of prey much larger than the gape. We suggest experimental methods to test these hypotheses empirically. PMID:17148206

  14. Mechanism of action of endosulfan as disruptor of gonadal steroidogenesis in the cichlid fish Cichlasoma dimerus.

    PubMed

    Da Cuña, Rodrigo H; Rey Vázquez, Graciela; Dorelle, Luciana; Rodríguez, Enrique M; Guimarães Moreira, Renata; Lo Nostro, Fabiana L

    2016-09-01

    The organochlorine pesticide endosulfan (ES) is used in several countries as a wide spectrum insecticide on crops with high commercial value. Due to its high toxicity to non-target animals, its persistence in the environment and its ability to act as an endocrine disrupting compound in fish, ES use is currently banned or restricted in many other countries. Previous studies on the cichlid fish Cichlasoma dimerus have shown that waterborne exposure to ES can lead to both decreased pituitary FSH content and histological alterations of testes. As gonadotropin-stimulated sex steroids release from gonads was inhibited by ES in vitro, the aim of the present study was to elucidate possible mechanisms of disruption of ES on gonadal steroidogenesis in C. dimerus, as well as compare the action of the active ingredient (AI) with that of currently used commercial formulations (CF). Testis and ovary fragments were incubated with ES (AI or CF) and/or steroidogenesis activators or precursors. Testosterone and estradiol levels were measured in the incubation media. By itself, ES did not affect hormone levels. Co-incubation with LH and the adenylate cyclase activator forskolin caused a decrease of the stimulated sex steroids release. When co-incubated with precursors dehydroandrostenedione and 17αhydroxyprogesterone, ES did not affect the increase caused by their addition alone. No differences were observed between the AI and CFs, suggesting that the effect on steroidogenesis disruption is mainly caused by the AI. Results indicate that action of ES takes place downstream of LH-receptor activation and upstream of the studied steroidogenic enzymes. PMID:27235598

  15. Protective role of Arapaima gigas fish scales: structure and mechanical behavior.

    PubMed

    Yang, Wen; Sherman, Vincent R; Gludovatz, Bernd; Mackey, Mason; Zimmermann, Elizabeth A; Chang, Edwin H; Schaible, Eric; Qin, Zhao; Buehler, Markus J; Ritchie, Robert O; Meyers, Marc A

    2014-08-01

    The scales of the arapaima (Arapaima gigas), one of the largest freshwater fish in the world, can serve as inspiration for the design of flexible dermal armor. Each scale is composed of two layers: a laminate composite of parallel collagen fibrils and a hard, highly mineralized surface layer. We review the structure of the arapaima scales and examine the functions of the different layers, focusing on the mechanical behavior, including tension and penetration of the scales, with and without the highly mineralized outer layer. We show that the fracture of the mineral and the stretching, rotation and delamination of collagen fibrils dissipate a significant amount of energy prior to catastrophic failure, providing high toughness and resistance to penetration by predator teeth. We show that the arapaima's scale has evolved to minimize damage from penetration by predator teeth through a Bouligand-like arrangement of successive layers, each consisting of parallel collagen fibrils with different orientations. This inhibits crack propagation and restricts damage to an area adjoining the penetration. The flexibility of the lamellae is instrumental to the redistribution of the compressive stresses in the underlying tissue, decreasing the severity of the concentrated load produced by the action of a tooth. The experimental results, combined with small-angle X-ray scattering characterization and molecular dynamics simulations, provide a complete picture of the mechanisms of deformation, delamination and rotation of the lamellae during tensile extension of the scale. PMID:24816264

  16. Three-link Swimming in Sand

    NASA Astrophysics Data System (ADS)

    Hatton, R. L.; Ding, Yang; Masse, Andrew; Choset, Howie; Goldman, Daniel

    2011-11-01

    Many animals move within in granular media such as desert sand. Recent biological experiments have revealed that the sandfish lizard uses an undulatory gait to swim within sand. Models reveal that swimming occurs in a frictional fluid in which inertial effects are small and kinematics dominate. To understand the fundamental mechanics of swimming in granular media (GM), we examine a model system that has been well-studied in Newtonian fluids: the three-link swimmer. We create a physical model driven by two servo-motors, and a discrete element simulation of the swimmer. To predict optimal gaits we use a recent geometric mechanics theory combined with empirically determined resistive force laws for GM. We develop a kinematic relationship between the swimmer's shape and position velocities and construct connection vector field and constraint curvature function visualizations of the system dynamics. From these we predict optimal gaits for forward, lateral and rotational motion. Experiment and simulation are in accord with the theoretical predictions; thus geometric tools can be used to study locomotion in GM.

  17. Use of electromyogram telemetry to assess swimming activity of adult spring Chinook salmon migrating past a Columbia River dam

    USGS Publications Warehouse

    Brown, R.S.; Geist, D.R.; Mesa, M.G.

    2006-01-01

    Electromyogram (EMG) radiotelemetry was used to estimate the swim speeds of spring Chinook salmon Oncorhynchus tshawytscha migrating upstream past a Columbia River dam. Electrodes from EMG transmitters were surgically implanted in the red muscle of fish captured at Bonneville Dam, and output from the tags was calibrated to defined swim speeds for each fish in a tunnel respirometer. The fish were then released below Bonneville Dam and radio-tracked as they migrated through the tailraces, fishways, and forebays of the dam. On average, swim speed was significantly higher when tagged salmon were moving through tailraces than when they were moving through other parts of the dam. Specifically, swim speeds for fish in tailraces (106.4 cm/s) were 23% higher than those of fish in fishways (84.9 cm/s) and 32% higher than those of fish in forebays (80.2 cm/s). Swim speeds were higher in fishways during the day than during the night, but there were no diel differences in swim speeds in tailraces and forebays. During dam passage, Chinook salmon spent the most time in tailraces, followed by fishways and forebays. ?? Copyright by the American Fisheries Society 2006.

  18. Cardiorespiratory performance and blood chemistry during swimming and recovery in three populations of elite swimmers: Adult sockeye salmon.

    PubMed

    Eliason, Erika J; Clark, Timothy D; Hinch, Scott G; Farrell, Anthony P

    2013-10-01

    Every year, millions of adult sockeye salmon (Oncorhynchus nerka) perform an arduous, once-in-a-lifetime migration up the Fraser River (BC, Canada) to return to their natal stream to spawn. The changes in heart rate, stroke volume, and arterio-venous oxygen extraction (i.e., factors determining rates of oxygen delivery to the tissues by the cardiovascular system) have never been directly and simultaneously measured along with whole animal oxygen uptake in a maximally swimming fish. Here, such measurements were made using three sockeye salmon populations (Early Stuart, Chilko and Quesnel), which each performed two consecutive critical swimming speed (Ucrit) challenges to provide a comprehensive quantification of cardiovascular physiology, oxygen status and blood chemistry associated with swimming and recovery. Swim performance, oxygen uptake, cardiac output, heart rate and stroke volume did not significantly vary at rest, during swimming or during recovery between populations or sexes. Despite incomplete metabolic recovery between swim challenges, all fish repeated their swim performance and similar quantitative changes in the cardiorespiratory variables were observed for each swim challenge. The high maximum cardiorespiratory performance and excellent repeat swim performance are clearly beneficial in allowing the salmon to maintain steady ground speeds and reach the distant spawning grounds in a timely manner. PMID:23880060

  19. Water flow and fin shape polymorphism in coral reef fishes.

    PubMed

    Binning, Sandra A; Roche, Dominique G

    2015-03-01

    Water flow gradients have been linked to phenotypic differences and swimming performance across a variety of fish assemblages. However, the extent to which water motion shapes patterns of phenotypic divergence within species remains unknown. We tested the generality of the functional relationship between swimming morphology and water flow by exploring the extent of fin and body shape polymorphism in 12 widespread species from three families (Acanthuridae, Labridae, Pomacentridae) of pectoral-fin swimming (labriform) fishes living across localized wave exposure gradients. The pectoral fin shape of Labridae and Acanthuridae species was strongly related to wave exposure: individuals with more tapered, higher aspect ratio (AR) fins were found on windward reef crests, whereas individuals with rounder, lower AR fins were found on leeward, sheltered reefs. Three of seven Pomacentridae species showed similar trends, and pectoral fin shape was also strongly related to wave exposure in pomacentrids when fin aspect ratios of three species were compared across flow habitats at very small spatial scales (<100 m) along a reef profile (reef slope, crest, and back lagoon). Unlike fin shape, there were no intraspecific differences in fish body fineless ratio across habitats or depths. Contrary to our predictions, there was no pattern relating species' abundances to polymorphism across habitats (i.e., abundance was not higher at sites where morphology is better adapted to the environment). This suggests that there are behavioral and/or physiological mechanisms enabling some species to persist across flow habitats in the absence of morphological differences. We suggest that functional relationships between swimming morphology and water flow not only structure species assemblages, but are yet another important variable contributing to phenotypic differences within species. The close links between fin shape polymorphism and local water flow conditions appear to be important for

  20. Antidepressant-like effects of the cannabinoid receptor ligands in the forced swimming test in mice: mechanism of action and possible interactions with cholinergic system.

    PubMed

    Kruk-Slomka, Marta; Michalak, Agnieszka; Biala, Grazyna

    2015-05-01

    The purpose of the experiments was to explore the role of the endocannabinoid system, through cannabinoid (CB) receptor ligands, nicotine and scopolamine, in the depression-related responses using the forced swimming test (FST) in mice. Our results revealed that acute injection of oleamide (10 and 20 mg/kg), a CB1 receptor agonist, caused antidepressant-like effect in the FST, while AM 251 (0.25-3 mg/kg), a CB1 receptor antagonist, did not provoke any effect in this test. Moreover, acute administration of both CB2 receptor agonist, JWH 133 (0.5 and 1 mg/kg) and CB2 receptor antagonist, AM 630 (0.5 mg/kg), exhibited antidepressant action. Antidepressant effects of oleamide and JWH 133 were attenuated by acute injection of both non-effective dose of AM 251, as well as AM 630. Among the all CB compounds used, only the combination of non-effective dose of oleamide (2.5 mg/kg) with non-effective dose of nicotine (0.5 mg/kg) caused an antidepressant effect. However, none of the CB receptor ligands, had influence on the antidepressant effects provoked by nicotine (0.2 mg/kg) injection. In turn, the combination of non-effective dose of oleamide (2.5 mg/kg); JWH (2 mg/kg) or AM 630 (2 mg/kg), but not of AM 251 (0.25 mg/kg), with non-effective dose of scopolamine (0.1 mg/kg), exhibited antidepressant properties. Indeed, all of the CB compounds used, intensified the antidepressant-like effects induced by an acute injection of scopolamine (0.3 mg/kg). Our results provide clear evidence that the endocannabinoid system participates in the depression-related behavior and through interactions with cholinergic system modulate these kind of responses. PMID:25660201

  1. Acute exposure to 2,4-dinitrophenol alters zebrafish swimming performance and whole body triglyceride levels.

    PubMed

    Marit, Jordan S; Weber, Lynn P

    2011-06-01

    While swimming endurance (critical swimming speed or U(crit)) and lipid stores have both been reported to acutely decrease after exposure to a variety of toxicants, the relationship between these endpoints has not been clearly established. In order to examine these relationships, adult zebrafish (Danio rerio) were aqueously exposed to solvent control (ethanol) or two nominal concentrations of 2,4-dinitrophenol (DNP), a mitochondrial electron transport chain uncoupler, for a 24-h period. Following exposure, fish were placed in a swim tunnel in clean water for swimming testing or euthanized immediately without testing, followed by analysis of whole body triglyceride levels. U(crit) decreased in both the 6 mg/L and 12 mg/L DNP groups, with 12 mg/L approaching the LC₅₀. A decrease in tail beat frequency was observed without a significant change in tail beat amplitude. In contrast, triglyceride levels were elevated in a concentration-dependent manner in the DNP exposure groups, but only in fish subjected to swimming tests. This increase in triglyceride stores may be due to a direct interference of DNP on lipid catabolism as well as increased triglyceride production when zebrafish were subjected to the co-stressors of swimming and toxicant exposure. Future studies should be directed at determining how acute DNP exposure combines with swimming to cause alterations in triglyceride accumulation. PMID:21406246

  2. Swim bladder function and buoyancy control in pink snapper (Pagrus auratus) and mulloway (Argyrosomus japonicus).

    PubMed

    Stewart, John; Hughes, Julian M

    2014-04-01

    Physoclist fish are able to regulate their buoyancy by secreting gas into their hydrostatic organ, the swim bladder, as they descend through the water column and by resorbing gas from their swim bladder as they ascend. Physoclists are restricted in their vertical movements due to increases in swim bladder gas volume that occur as a result of a reduction in hydrostatic pressure, causing fish to become positively buoyant and risking swim bladder rupture. Buoyancy control, rates of swim bladder gas exchange and restrictions to vertical movements are little understood in marine teleosts. We used custom-built hyperbaric chambers and laboratory experiments to examine these aspects of physiology for two important fishing target species in southern Australia, pink snapper (Pagrus auratus) and mulloway (Argyrosomus japonicus). The swim bladders of pink snapper and mulloway averaged 4.2 and 4.9 % of their total body volumes, respectively. The density of pink snapper was not significantly different to the density of seawater (1.026 g/ml), whereas mulloway were significantly denser than seawater. Pink snapper secreted gas into their swim bladders at a rate of 0.027 ± 0.005 ml/kg/min (mean ± SE), almost 4 times faster than mulloway (0.007 ± 0.001 ml/kg/min). Rates of swim bladder gas resorption were 11 and 6 times faster than the rates of gas secretion for pink snapper and mulloway, respectively. Pink snapper resorbed swim bladder gas at a rate of 0.309 ± 0.069 ml/kg/min, 7 times faster than mulloway (0.044 ± 0.009 ml/kg/min). Rates of gas exchange were not affected by water pressure or water temperature over the ranges examined in either species. Pink snapper were able to acclimate to changes in hydrostatic pressure reasonably quickly when compared to other marine teleosts, taking approximately 27 h to refill their swim bladders from empty. Mulloway were able to acclimate at a much slower rate, taking approximately 99 h to refill their swim bladders. We estimated that the

  3. Simulating mechanisms for dispersal, production and stranding of small forage fish in temporary wetland habitats

    USGS Publications Warehouse

    Yurek, Simeon; DeAngelis, Donald L.; Trexler, Joel C.; Jopp, Fred; Donalson, Douglas D.

    2013-01-01

    Movement strategies of small forage fish (<8 cm total length) between temporary and permanent wetland habitats affect their overall population growth and biomass concentrations, i.e., availability to predators. These fish are often the key energy link between primary producers and top predators, such as wading birds, which require high concentrations of stranded fish in accessible depths. Expansion and contraction of seasonal wetlands induce a sequential alternation between rapid biomass growth and concentration, creating the conditions for local stranding of small fish as they move in response to varying water levels. To better understand how landscape topography, hydrology, and fish behavior interact to create high densities of stranded fish, we first simulated population dynamics of small fish, within a dynamic food web, with different traits for movement strategy and growth rate, across an artificial, spatially explicit, heterogeneous, two-dimensional marsh slough landscape, using hydrologic variability as the driver for movement. Model output showed that fish with the highest tendency to invade newly flooded marsh areas built up the largest populations over long time periods with stable hydrologic patterns. A higher probability to become stranded had negative effects on long-term population size, and offset the contribution of that species to stranded biomass. The model was next applied to the topography of a 10 km × 10 km area of Everglades landscape. The details of the topography were highly important in channeling fish movements and creating spatiotemporal patterns of fish movement and stranding. This output provides data that can be compared in the future with observed locations of fish biomass concentrations, or such surrogates as phosphorus ‘hotspots’ in the marsh.

  4. Swimming Performance and Metabolism of Golden Shiners

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The swimming ability and metabolism of golden shiners, Notemigonus crysoleucas, was examined using swim tunnel respirometery. The oxygen consumption and tail beat frequencies at various swimming speeds, an estimation of the standard metabolic rate, and the critical swimming speed (Ucrit) was determ...

  5. 21 CFR 1250.89 - Swimming pools.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Swimming pools. 1250.89 Section 1250.89 Food and... SANITATION Sanitation Facilities and Conditions on Vessels § 1250.89 Swimming pools. (a) Fill and draw swimming pools shall not be installed or used. (b) Swimming pools of the recirculation type shall...

  6. A meta-analysis synthesizing the effects of pesticides on swim speed and activity of aquatic vertebrates.

    PubMed

    Shuman-Goodier, Molly E; Propper, Catherine R

    2016-09-15

    Pesticide contaminants are ubiquitous in aquatic environments and pose a threat to biodiversity. Pesticides also have diverse mechanisms of action that make it difficult to identify impacts on exposed wildlife. Behavioral measures represent an important link between physiological and ecological processes, and are often used to generalize sub-lethal effects of pesticide exposure. In order to bridge the toxicological and behavioral literature, and identify chemical classes that denote the largest threat, we conducted a meta-analysis summarizing the effects of pesticides on swim speed and activity of aquatic vertebrates. We found that exposure to environmentally relevant concentrations of pesticides reduced the swim speed of exposed amphibians and fish by 35%, and reduced overall activity by 72%. There were also differences in the magnitude of this effect across chemical classes, which likely reflect underlying physiological processes. Pyrethroids, carbamates, and organophosphates all produced a large decrease in swim speed, where as phosphonoglycines and triazines showed no overall effect. Pyrethroids, carbamates, organophosphates, organochlorines, and organotins also produced a large decrease in activity, while phosphonoglycines had no overall effect, and triazines had the opposite effect of increasing activity. Our results indicate that even sub-lethal concentrations of pesticides have a strong effect on critical behaviors of aquatic vertebrates, which can affect fitness and alter species interactions. We expect our synthesis can be used to identify chemical classes producing the largest sub-lethal effects for further research and management. PMID:27261557

  7. Effects of Acoustic Transmitters on the Swimming Performance and Predator Avoidance of Juvenile Chinook Salmon

    SciTech Connect

    Anglea, Steven M.; Geist, David R.; Brown, Richard S.; Deters, Katherine A.; Mcdonald, Robert D.

    2004-03-01

    The objective of this study was to determine if juvenile chinook salmon (Oncorhynchus tshawytscha) were negatively influenced by the implantation of acoustic transmitters. The critical swimming speed (Ucrit) of tagged fish, sham (surgery but no tag), and control fish was measured in a respirometer to determine tag effects on swimming performance. Predator avoidance was evaluated by comparing the proportion of each treatment group eaten: active tag, inactive tag, sham, and control after being exposed to piscivorous adult rainbow trout (O. mykiss). Results from this study demonstrated that the surgical implantation of acoustic tags in juvenile fall chinook salmon does not significantly affect swimming performance. Swimming performance was similar between treatment groups (control, sham, and inactive tag) at 1- and 21-day post-surgery intervals. Critical swimming speeds for all treatment groups were similar to values reported in the literature. Implantation of acoustic transmitters (active and inactive) did not result in tagged fish being more susceptible to predation over untagged fish. Percentages of each prey group consumed in each of the four trials were highly variable and demonstrated no obvious selection preference by adult rainbow trout. In summary, measurable differences were not found between tagged and un-tagged fish, however, trends were consistent in the two experiments with tagged fish consistently performing slightly worse than un-tagged fish. We conclude that based on the current body of knowledge and findings of the present study, fish implanted with an acoustic tag perform and/or behave similarly to the population-at-large recognizing that subtle differences exist in the behavior of tagged fish.

  8. Models of the mechanical sensitivity and growth of otoliths in fish.

    PubMed

    Kondrachuk, Alexander V

    2003-01-01

    It has been suggested that, in the fish, the change of otolith mass during development under altered gravity conditions and the growth of otoliths in normal conditions, are determined by feedback between otolith dynamics and the processes that regulate otolith growth. The hypothesis originates from an oscillator model of the otolith in which otolith mass is one of the parameters. However, the validity of this hypothesis is not obvious and has not been experimentally verified. We tested this hypothesis by comparing the oscillator model with a simplified spatially distributed model of the otolith. It was shown that in the case of a spatially distributed fixation of the otolith plate (otoconial layer) to the macular surface, the mechanical sensitivity of the otolith does not depend on the total otolith mass nor on its longitudinal size. It is determined by otolith thickness, the Young's modulus and viscosity of gel layer of the growing otolith. These parameters may change in order to maintain otolith sensitivity under conditions (such as growth or altered gravity) that change the dynamics of otolith movement. PMID:15096663

  9. P-gp expression in brown trout erythrocytes: evidence of a detoxification mechanism in fish erythrocytes

    PubMed Central

    Valton, Emeline; Amblard, Christian; Wawrzyniak, Ivan; Penault-Llorca, Frederique; Bamdad, Mahchid

    2013-01-01

    Blood is a site of physiological transport for a great variety of molecules, including xenobiotics. Blood cells in aquatic vertebrates, such as fish, are directly exposed to aquatic pollution. P-gp are ubiquitous “membrane detoxification proteins” implicated in the cellular efflux of various xenobiotics, such as polycyclic aromatic hydrocarbons (PAHs), which may be pollutants. The existence of this P-gp detoxification system inducible by benzo [a] pyrene (BaP), a highly cytotoxic PAH, was investigated in the nucleated erythrocytes of brown trout. Western blot analysis showed the expression of a 140-kDa P-gp in trout erythrocytes. Primary cultures of erythrocytes exposed to increasing concentrations of BaP showed no evidence of cell toxicity. Yet, in the same BaP-treated erythrocytes, P-gp expression increased significantly in a dose-dependent manner. Brown trout P-gp erythrocytes act as membrane defence mechanism against the pollutant, a property that can be exploited for future biomarker development to monitor water quality. PMID:24305632

  10. Plasma lactate and glucose flushes following burst swimming in silver trevally (Pseudocaranx dentex: Carangidae) support the "releaser" hypothesis.

    PubMed

    Wells, R M G; Baldwin, J

    2006-03-01

    Silver trevally (Pseudocaranx dentex) are highly athletic marine teleosts inhabiting the tropical waters of the Great Barrier Reef, Australia. Burst swimming increased plasma lactate from 1.6 +/- 0.4 S.D. to 21.6 +/- 3.3 mM (N = 6), among the highest values reported for functional hypoxia in fish. These data support the hypothesis that elite swimmers release lactate produced in the myotome into the circulation following anaerobic burst activity. The fish further developed a hyperglycaemic response to burst exercise with plasma glucose increasing from 6.6 +/- 2.0 to 13.2 +/- 2.3 mM (N = 6). Post-exercise erythrocyte swelling also occurred, but nucleoside triphosphate levels remained unaltered and do not provide a mechanism to modulate haemoglobin function during exercise. Metabolism of the blood cells appeared to be fuelled by both lactate and glucose. PMID:16459118

  11. Exercise-training intervention studies in competitive swimming.

    PubMed

    Aspenes, Stian Thoresen; Karlsen, Trine

    2012-06-01

    Competitive swimming has a long history and is currently one of the largest Olympic sports, with 16 pool events. Several aspects separate swimming from most other sports such as (i) the prone position; (ii) simultaneous use of arms and legs for propulsion; (iii) water immersion (i.e. hydrostatic pressure on thorax and controlled respiration); (iv) propulsive forces that are applied against a fluctuant element; and (v) minimal influence of equipment on performance. Competitive swimmers are suggested to have specific anthropometrical features compared with other athletes, but are nevertheless dependent on physiological adaptations to enhance their performance. Swimmers thus engage in large volumes of training in the pool and on dry land. Strength training of various forms is widely used, and the energetic systems are addressed by aerobic and anaerobic swimming training. The aim of the current review was to report results from controlled exercise training trials within competitive swimming. From a structured literature search we found 17 controlled intervention studies that covered strength or resistance training, assisted sprint swimming, arms-only training, leg-kick training, respiratory muscle training, training the energy delivery systems and combined interventions across the aforementioned categories. Nine of the included studies were randomized controlled trials. Among the included studies we found indications that heavy strength training on dry land (one to five repetitions maximum with pull-downs for three sets with maximal effort in the concentric phase) or sprint swimming with resistance towards propulsion (maximal pushing with the arms against fixed points or pulling a perforated bowl) may be efficient for enhanced performance, and may also possibly have positive effects on stroke mechanics. The largest effect size (ES) on swimming performance was found in 50 m freestyle after a dry-land strength training regimen of maximum six repetitions across three

  12. Healthy Swimming/Recreational Water

    MedlinePlus

    ... Index of Water-Related Topics Featured Partners Healthy Water Sites Healthy Water Drinking Water Healthy Swimming Global WASH Other Uses of Water WASH-related Emergencies & Outbreaks Water, Sanitation, & Environmentally-related ...

  13. System Wide Information Management (SWIM)

    NASA Technical Reports Server (NTRS)

    Hritz, Mike; McGowan, Shirley; Ramos, Cal

    2004-01-01

    This viewgraph presentation lists questions regarding the implementation of System Wide Information Management (SWIM). Some of the questions concern policy issues and strategies, technology issues and strategies, or transition issues and strategies.

  14. Energy exchanges of swimming man

    NASA Technical Reports Server (NTRS)

    Nadel, E. R.; Holmer, I.; Bergh, U.; Astrand, P.-O.; Stolwijk, J. A. J.

    1974-01-01

    Three male swimmers underwent 10-min resting and 20-min swimming (breaststroke) exposures in a swimming flume. Water temperatures in separate exposures were 18, 26, and 33 C. At each water temperature the subjects rested and swam at water velocities of 0.50, 0.75, and 0.95 m/sec, which were designed to produce around 40, 70, and 100% of maximal aerobic power. Measurements were made of esophageal temperature, four skin temperatures, water temperature, heat flow from five local skin surfaces (Hatfield-Turner disks), and oxygen uptake. Calculations were made of mean area-weighted skin temperature and heat flow, metabolic rate, and heat storage. Internal body temperature changes after 20 min of swimming were related to water temperature, swimming intensity, and body composition.

  15. Swimming in a granular frictional fluid

    NASA Astrophysics Data System (ADS)

    Goldman, Daniel

    2012-02-01

    X-ray imaging reveals that the sandfish lizard swims within granular media (sand) using axial body undulations to propel itself without the use of limbs. To model the locomotion of the sandfish, we previously developed an empirical resistive force theory (RFT), a numerical sandfish model coupled to an experimentally validated Discrete Element Method (DEM) model of the granular medium, and a physical robot model. The models reveal that only grains close to the swimmer are fluidized, and that the thrust and drag forces are dominated by frictional interactions among grains and the intruder. In this talk I will use these models to discuss principles of swimming within these granular ``frictional fluids". The empirical drag force laws are measured as the steady-state forces on a small cylinder oriented at different angles relative to the displacement direction. Unlike in Newtonian fluids, resistive forces are independent of speed. Drag forces resemble those in viscous fluids while the ratio of thrust to drag forces is always larger in the granular media than in viscous fluids. Using the force laws as inputs, the RFT overestimates swimming speed by approximately 20%. The simulation reveals that this is related to the non-instantaneous increase in force during reversals of body segments. Despite the inaccuracy of the steady-state assumption, we use the force laws and a recently developed geometric mechanics theory to predict optimal gaits for a model system that has been well-studied in Newtonian fluids, the three-link swimmer. The combination of the geometric theory and the force laws allows us to generate a kinematic relationship between the swimmer's shape and position velocities and to construct connection vector field and constraint curvature function visualizations of the system dynamics. From these we predict optimal gaits for forward, lateral and rotational motion. Experiment and simulation are in accord with the theoretical prediction, and demonstrate that

  16. Swimming endurance of bull trout, lake trout, arctic char, and rainbow trout following challenge with Renibacterium salmoninarum

    USGS Publications Warehouse

    Jones, D.T.; Moffitt, C.M.

    2004-01-01

    We tested the swimming endurance of juvenile bull trout Salvelinus confluentus, lake trout S. namaycush, Arctic char S. alpinus, and rainbow trout Oncorhynchus mykiss at 9??C and 15??C to determine whether sublethal infection from a moderate challenge of Renibacterium salmoninarum administered months before testing affected the length of time fish could maintain a swimming speed of 5-6 body lengths per second in an experimental flume. Rainbow trout and Arctic char swam longer in trials than did bull trout or lake trout, regardless of challenge treatment. When we tested fish 14-23 weeks postchallenge, we found no measurable effect of R. salmoninarum on the swimming endurance of the study species except for bull trout, which showed a mixed response. We conducted additional trials with bull trout 5-8 weeks postchallenge to determine whether increasing the challenge dose would affect swimming endurance and hematocrit. In those tests, bull trout with clinical signs of disease and those exposed to the highest challenge doses had significantly reduced swimming endurance compared with unchallenged control fish. Fish hematocrit levels measured at the end of all swimming endurance tests varied among species and between test temperatures, and patterns were not always consistent between challenged and control fish.

  17. Strong Static Magnetic Fields Elicit Swimming Behaviors Consistent with Direct Vestibular Stimulation in Adult Zebrafish

    PubMed Central

    Ward, Bryan K.; Tan, Grace X-J; Roberts, Dale C.; Della Santina, Charles C.; Zee, David S.; Carey, John P.

    2014-01-01

    Zebrafish (Danio rerio) offer advantages as model animals for studies of inner ear development, genetics and ototoxicity. However, traditional assessment of vestibular function in this species using the vestibulo-ocular reflex requires agar-immobilization of individual fish and specialized video, which are difficult and labor-intensive. We report that using a static magnetic field to directly stimulate the zebrafish labyrinth results in an efficient, quantitative behavioral assay in free-swimming fish. We recently observed that humans have sustained nystagmus in high strength magnetic fields, and we attributed this observation to magnetohydrodynamic forces acting on the labyrinths. Here, fish were individually introduced into the center of a vertical 11.7T magnetic field bore for 2-minute intervals, and their movements were tracked. To assess for heading preference relative to a magnetic field, fish were also placed in a horizontally oriented 4.7T magnet in infrared (IR) light. A sub-population was tested again in the magnet after gentamicin bath to ablate lateral line hair cell function. Free-swimming adult zebrafish exhibited markedly altered swimming behavior while in strong static magnetic fields, independent of vision or lateral line function. Two-thirds of fish showed increased swimming velocity or consistent looping/rolling behavior throughout exposure to a strong, vertically oriented magnetic field. Fish also demonstrated altered swimming behavior in a strong horizontally oriented field, demonstrating in most cases preferred swimming direction with respect to the field. These findings could be adapted for ‘high-throughput’ investigations of the effects of environmental manipulations as well as for changes that occur during development on vestibular function in zebrafish. PMID:24647586

  18. Strong static magnetic fields elicit swimming behaviors consistent with direct vestibular stimulation in adult zebrafish.

    PubMed

    Ward, Bryan K; Tan, Grace X-J; Roberts, Dale C; Della Santina, Charles C; Zee, David S; Carey, John P

    2014-01-01

    Zebrafish (Danio rerio) offer advantages as model animals for studies of inner ear development, genetics and ototoxicity. However, traditional assessment of vestibular function in this species using the vestibulo-ocular reflex requires agar-immobilization of individual fish and specialized video, which are difficult and labor-intensive. We report that using a static magnetic field to directly stimulate the zebrafish labyrinth results in an efficient, quantitative behavioral assay in free-swimming fish. We recently observed that humans have sustained nystagmus in high strength magnetic fields, and we attributed this observation to magnetohydrodynamic forces acting on the labyrinths. Here, fish were individually introduced into the center of a vertical 11.7T magnetic field bore for 2-minute intervals, and their movements were tracked. To assess for heading preference relative to a magnetic field, fish were also placed in a horizontally oriented 4.7T magnet in infrared (IR) light. A sub-population was tested again in the magnet after gentamicin bath to ablate lateral line hair cell function. Free-swimming adult zebrafish exhibited markedly altered swimming behavior while in strong static magnetic fields, independent of vision or lateral line function. Two-thirds of fish showed increased swimming velocity or consistent looping/rolling behavior throughout exposure to a strong, vertically oriented magnetic field. Fish also demonstrated altered swimming behavior in a strong horizontally oriented field, demonstrating in most cases preferred swimming direction with respect to the field. These findings could be adapted for 'high-throughput' investigations of the effects of environmental manipulations as well as for changes that occur during development on vestibular function in zebrafish. PMID:24647586

  19. Estimating propulsive forces--sink or swim?

    PubMed

    Lauder, M A; Dabnichki, P

    2005-10-01

    The purpose of this study was to investigate the validity of hydrodynamic force estimation in swimming as calculated by the quasi-static approach. To achieve this a full-scale mechanical arm was developed, built and tested. The mechanical arm, covered with a prosthetic shell and driven at the shoulder was used to simulate a single plane underwater rotation at four elbow configurations. A computer program controlled the shoulder movement to achieve a replicable angular velocity profile for each arm movement. A strain gauge system was used to directly measure the generated arm torque. Repeated trials were conducted at fixed elbow angles of 110 degrees, 135 degrees, 160 degrees and 180 degrees. All trials were filmed using a three-dimensional underwater set-up. Each trial was digitised at 25 Hz and the hydrodynamic drag force profile of the hand calculated using the quasi-static procedure. From these data, the estimated shoulder torque was calculated and compared to the direct measurement of shoulder torque from the mechanical arm. The results showed that the arm produced a repeatable movement through the water. The shoulder torque profiles using the direct measure (the arm) and the indirect measures (quasi-static approach) differed considerably. The quasi-static approach appears not to accurately reflect the hydrodynamic force profile generated by the arm movement in swimming. Furthermore, it seems that the swimmer's hand contribution is overstated in up to date studies. It is essential that the propulsive mechanisms in swimming be further investigated if factors underpinning an optimal technique are to be established. PMID:16045915

  20. Relationships Between Metabolic Rate, Muscle Electromyograms and Swim Performance of Adult Chinook Salmon

    SciTech Connect

    Geist, David R.; Brown, Richard S.; Cullinan, Valerie I.; Mesa, Matthew G.; VanderKooi, S P.; McKinstry, Craig A.

    2003-10-01

    In 2000 Pacific Northwest National Laboratory initiated a two-year study to investigate the metabolic rate and swimming performance and to estimate the total energy used (i.e., aerobic and anaerobic) by adult spring Chinook salmon migrating upstream through a large hydropower dam on the Columbia River. The investigation involved one year of laboratory study and one year of field study at Bonneville Dam. The objectives of the laboratory study, reported here, were to (1) measure active rates of oxygen consumption of adult spring chinook salmon at three water temperatures over a range of swimming speeds; (2) estimate the Ucrit of adult spring chinook salmon; and (3) monitor EMGs of red and white muscle in the salmon over a range of swimming speeds. Future papers will report on the results of the field study. Our results indicated that the rate of oxygen consumption and red and white muscle activity in adult spring chinook salmon were strongly correlated with swimming speed over a range of fish sizes and at three different temperatures. Active oxygen consumption increased linearly with swim speed before leveling off at speeds at or above Ucrit. This pattern was similar at each water temperature and indicated that fish were approaching their maximal aerobic oxygen consumption at higher swim speeds. Modeling showed that temperature, but not size or sex, influenced the relation between V02 and swim speed, thus a V02-swim speed model based on temperature (but independent of sex and size) should be a biologically relevant way of estimating the energy use of fish in the wild.

  1. On the hydrodynamics of fish schooling

    NASA Astrophysics Data System (ADS)

    Borazjani, Iman; Daghooghi, Mohsen

    2013-11-01

    A Considerable number of fish species swim in a coordinated manner within approximately constant and equal distance from each other, forming a pattern which is referred to as a fish school. It is believed that fish schooling results in more efficient swimming. However, no experimental evidence has conclusively shown the hydrodynamic effects of neighboring fish on swimming, probably due to the challenges involved in measuring the performance under controlled conditions in a school. We investigate possible hydrodynamical effects of fish schooling by constructing an infinite school of virtual swimmers based on a mackerel fish body and carangiform kinematics. We carry out our self-propelled simulation based on prescribed undulations of the fish body (assuming that all of the fish in the school move in exact same manner) and calculating motion of the center of mass. One of the most important geometrical factors of the fish schooling pattern seems to be the distance between two adjacent fish in the school. Therefore, we examined fish schools with different distances of two adjacent fish. This work was partly supported by the Center for Computational Research (CCR), University at Buffalo.

  2. FISH ACUTE TOXICITY SYNDROMES IN THE DEVELOPMENT OF MECHANISM-SPECIFIC QSARS.

    EPA Science Inventory

    The focus of this report is to summarize the development and status of the fish acute toxicity syndrome (FATS) research effort. hus far, FATS associated with nonpolar narcotics, oxidative phosphorylation uncouplers, respiratory membrane irritants, acetylcholinesterase (AChE) inhi...

  3. Eye retraction in the giant guitarfish, Rhynchobatus djiddensis (Elasmobranchii: Batoidea): a novel mechanism for eye protection in batoid fishes.

    PubMed

    Tomita, Taketeru; Murakumo, Kiyomi; Miyamoto, Kei; Sato, Keiichi; Oka, Shin-ichiro; Kamisako, Haruka; Toda, Minoru

    2016-02-01

    Eye retraction behavior has evolved independently in some vertebrate linages such as mudskippers (fish), frogs and salamanders (amphibians), and cetaceans (mammals). In this paper, we report the eye retraction behavior of the giant guitarfish (Rhynchobatus djiddensis) for the first time, and discuss its mechanism and function. The eye retraction distance was nearly the same as the diameter of the eyeball itself, indicating that eye retraction in the giant guitarfish is probably one of the largest among vertebrates. Eye retraction is achieved by unique arrangement of the eye muscle: one of the anterior eye muscles (the obliquus inferior) is directed ventrally from the eyeball and attaches to the ventral surface of the neurocranium. Due to such muscle arrangement, the obliquus inferior can pull the eyeball ventrally. This mechanism was also confirmed by electrical stimulation of the obliquus inferior. The eye retraction ability of the giant guitarfish likely represents a novel eye protection behavior of elasmobranch fishes. PMID:26468088

  4. Lake Erie...A Day in the Life of a Fish.

    ERIC Educational Resources Information Center

    Canning, Maureen; Dunlevy, Margie

    This elementary school teaching unit was developed as a part of a series of units that deal with Lake Erie. This unit was developed to enable children to: (1) examine a moving fish; (2) conduct experiments with a live fish; (3) understand the swimming habits of fish; (4) learn how fish breathe; (5) recognize different methods of fish protection…

  5. Premaxillary movements in cyprinodontiform fishes: an unusual protrusion mechanism facilitates "picking" prey capture.

    PubMed

    Ferry-Graham, Lara A; Gibb, Alice C; Hernandez, L Patricia

    2008-01-01

    Premaxillary protrusion is hypothesized to confer a number of feeding advantages to teleost fishes; however, most proposed advantages relate to enhanced stealth or suction production during prey capture. Cyprinodontiformes exhibit an unusual form of premaxillary protrusion where the descending process of the premaxilla does not rotate anteriorly to occlude the sides of the open mouth during prey capture. Instead, the premaxilla is protruded such that it gives the impression of a beak during prey capture. We quantified premaxillary kinematics during feeding in four cyprinodontiform taxa and compared them with three percomorph taxa to identify any performance consequences of this protrusion mechanism. Individual prey capture events were recorded using digital high-speed video at 250-500 frames per second (n >or= 4 individuals, >or= 4 strikes per individual). Species differed in the timing of movement and the maximum displacement of the premaxilla during the gape cycle and in the contribution of the premaxilla to jaw closing. Cyprinodontiform taxa produced less premaxillary protrusion than the percomorph taxa, and were consistently slower in the time to maximum gape. Further, it appears cyprinodontiforms can alter the contribution of the premaxilla to mouth closure on an event-specific basis. We were able to demonstrate that, within at least one species, this variability is associated with the location of the prey (bottom vs. water column). Cyprinodontiform upper jaw movements likely reflect increased dexterity associated with a foraging ecology where prey items are "picked" from a variety of locations: the bottom, water column, or surface. We postulate that dexterity requires slow, precisely controlled jaw movements; thus, may be traded off for some aspects of suction-feeding performance, such as protrusion distance and speed. PMID:18619823

  6. Fish flavor.

    PubMed

    Kawai, T

    1996-02-01

    This article reviews features of flavor in three groups of fishes and summarizes them as follows: (1) fresh saltwater fish are nearly odorless because they contain a small quantity of volatiles; (2 freshwater fish give off pyrrolidine and earthy-odor compounds, which are responsible for their maturity and surrounding water pollution, and (3) euryhaline fish exhibit a variety of unsaturated carbonyls and alcohols derived from enzymatic and nonenzymatic oxidation of polyunsaturated fatty acids (PAs). These features are discussed, as are the effects of different enzymatic activities on PA oxidation and the effects of pH on mechanisms of formation of the volatiles. The monotonous volatile constitution of saltwater fish is likely caused by an unknown antioxidation system restraining the fish from oxidizing. The variety of constitution of euryhaline fish, especially that of anadromous fish under spawning conditions, could result from the loss of that system. The thermal environments of heated foods are also reviewed. The basic environment of fish, which allows the formation of flavor compounds, is discussed to confirm the volatiles found in unheated fish. PMID:8744606

  7. Investigating hydrologic alteration as a mechanism of fish assemblage shifts in urbanizing streams

    USGS Publications Warehouse

    Roy, A.H.; Freeman, Mary C.; Freeman, B.J.; Wenger, S.J.; Ensign, W.E.; Meyer, J.L.

    2005-01-01

    Stream biota in urban and suburban settings are thought to be impaired by altered hydrology; however, it is unknown what aspects of the hydrograph alter fish assemblage structure and which fishes are most vulnerable to hydrologic alterations in small streams. We quantified hydrologic variables and fish assemblages in 30 small streams and their subcatchments (area 8?20 km2) in the Etowah River Catchment (Georgia, USA). We stratified streams and their subcatchments into 3 landcover categories based on imperviousness (20% of subcatchment), and then estimated the degree of hydrologic alteration based on synoptic measurements of baseflow yield. We derived hydrologic variables from stage gauges at each study site for 1 y (January 2003?2004). Increased imperviousness was positively correlated with the frequency of storm events and rates of the rising and falling limb of the hydrograph (i.e., storm ``flashiness??) during most seasons. Increased duration of low flows associated with imperviousness only occurred during the autumn low-flow period, and this measure corresponded with increased richness of lentic tolerant species. Altered storm flows in summer and autumn were related to decreased richness of endemic, cosmopolitan, and sensitive fish species, and decreased abundance of lentic tolerant species. Species predicted to be sensitive to urbanization, based on specific life-history or habitat requirements, also were related to stormflow variables and % fine bed sediment in riffles. Overall, hydrologic variables explained 22 to 66% of the variation in fish assemblage richness and abundance. Linkages between hydrologic alteration and fish assemblages were potentially complicated by contrasting effects of elevated flows on sediment delivery and scour, and mediating effects of high stream gradient on sediment delivery from elevated flows. However, stormwater management practices promoting natural hydrologic regimes are likely to reduce the impacts of catchment imperviousness

  8. Investigating hydrologic alteration as a mechanism of fish assemblage shifts in urbanizing streams

    USGS Publications Warehouse

    Roy, A.H.; Freeman, Mary C.; Freeman, B.J.; Wenger, S.J.; Ensign, W.E.; Meyer, J.L.

    2005-01-01

    Stream biota in urban and suburban settings are thought to be impaired by altered hydrology; however, it is unknown what aspects of the hydrograph alter fish assemblage structure and which fishes are most vulnerable to hydrologic alterations in small streams. We quantified hydrologic variables and fish assemblages in 30 small streams and their subcatchments (area 8-20 km 2) in the Etowah River Catchment (Georgia, USA). We stratified streams and their subcatchments into 3 landcover categories based on imperviousness (20% of subcatchment), and then estimated the degree of hydrologic alteration based on synoptic measurements of baseflow yield. We derived hydrologic variables from stage gauges at each study site for 1 y (January 2003-2004). Increased imperviousness was positively correlated with the frequency of storm events and rates of the rising and falling limb of the hydrograph (i.e, storm "flashiness") during most seasons. Increased duration of low flows associated with imperviousness only occurred during the autumn low-flow period, and this measure corresponded with increased richness of lentic tolerant species. Altered storm flows in summer and autumn were related to decreased richness of endemic, cosmopolitan, and sensitive fish species, and decreased abundance of lentic tolerant species. Species predicted to be sensitive to urbanization, based on specific life-history or habitat requirements, also were related to stormflow variables and % fine bed sediment in riffles. Overall, hydrologic variables explained 22 to 66% of the variation in fish assemblage richness and abundance Linkages between hydrologic alteration and fish assemblages were potentially complicated by contrasting effects of elevated flows on sediment delivery and scour, and mediating effects of high stream gradient on sediment delivery from elevated flows. However, stormwater management practices promoting natural hydrologic regimes are likely to reduce the impacts of catchment imperviousness on

  9. Nutrition for swimming.

    PubMed

    Shaw, Gregory; Boyd, Kevin T; Burke, Louise M; Koivisto, Anu

    2014-08-01

    Swimming is a sport that requires considerable training commitment to reach individual performance goals. Nutrition requirements are specific to the macrocycle, microcycle, and individual session. Swimmers should ensure suitable energy availability to support training while maintaining long term health. Carbohydrate intake, both over the day and in relation to a workout, should be manipulated (3-10 g/kg of body mass/day) according to the fuel demands of training and the varying importance of undertaking these sessions with high carbohydrate availability. Swimmers should aim to consume 0.3 g of high-biological-value protein per kilogram of body mass immediately after key sessions and at regular intervals throughout the day to promote tissue adaptation. A mixed diet consisting of a variety of nutrient-dense food choices should be sufficient to meet the micronutrient requirements of most swimmers. Specific dietary supplements may prove beneficial to swimmers in unique situations, but should be tried only with the support of trained professionals. All swimmers, particularly adolescent and youth swimmers, are encouraged to focus on a well-planned diet to maximize training performance, which ensures sufficient energy availability especially during periods of growth and development. Swimmers are encouraged to avoid rapid weight fluctuations; rather, optimal body composition should be achieved over longer periods by modest dietary modifications that improve their food choices. During periods of reduced energy expenditure (taper, injury, off season) swimmers are encouraged to match energy intake to requirement. Swimmers undertaking demanding competition programs should ensure suitable recovery practices are used to maintain adequate glycogen stores over the entirety of the competition period. PMID:24903758

  10. Mechanisms of maintenance of tropical freshwater fish communities in the face of disturbance.

    PubMed

    Martin-Smith, K M; Laird, L M; Bullough, L; Lewis, M G

    1999-11-29

    Community resistance to, and resilience from, perturbation will determine the trajectory of recovery from disturbance. Although selective timber extraction is considered a severe disturbance, fish communities from headwater streams around Danum Valley Field Centre, Sabah, Malaysia, showed few long-term changes in species composition or abundance. However, some species showed short-term (< 18 months) absence or decrease in abundance. These observations suggested that both resistance and resilience were important in maintaining long-term fish community structure. Resistance to perturbation was tested by monitoring fish communities before and after the creation of log-debris dams, while resilience was investigated by following the time-course of recolonization following complete removal of all fish. High community resistance was generally shown although the response was site-specific, dependent on the composition of the starting community, the size of the stream and physical habitat changes. High resilience was demonstrated in all recolonization experiments with strong correlations between pre- and post-defaunation communities, although there was a significant difference between pool and riffle habitats in the time-course of recovery. These differences can be explained by the movement characteristics of the species found in the different habitats. Resilience appeared to be a more predictable characteristic of the community than resistance and the implications of this for ensuring the long-term persistence of fish in the area are discussed. PMID:11605623

  11. Bioinspiration from fish for smart material design and function

    NASA Astrophysics Data System (ADS)

    Lauder, G. V.; Madden, P. G. A.; Tangorra, J. L.; Anderson, E.; Baker, T. V.

    2011-09-01

    Fish are a potentially rich source of inspiration for the design of smart materials. Fish exemplify the use of flexible materials to generate forces during locomotion, and a hallmark of fish functional design is the use of body and fin deformation to power propulsion and maneuvering. As a result of nearly 500 million years of evolutionary experimentation, fish design has a number of interesting features of note to materials engineers. In this paper we first provide a brief general overview of some key features of the mechanical design of fish, and then focus on two key properties of fish: the bilaminar mechanical design of bony fish fin rays that allows active muscular control of curvature, and the role of body flexibility in propulsion. After describing the anatomy of bony fish fin rays, we provide new data on their mechanical properties. Three-point bending tests and measurement of force inputs to and outputs from the fin rays show that these fin rays are effective displacement transducers. Fin rays in different regions of the fin differ considerably in their material properties, and in the curvature produced by displacement of one of the two fin ray halves. The mean modulus for the proximal (basal) region of the fin rays was 1.34 GPa, but this varied from 0.24 to 3.7 GPa for different fin rays. The distal fin region was less stiff, and moduli for the different fin rays measured varied from 0.11 to 0.67 GPa. These data are similar to those for human tendons (modulus around 0.5 GPa). Analysis of propulsion using flexible foils controlled using a robotic flapping device allows investigation of the effect of altering flexural stiffness on swimming speed. Flexible foils with the leading edge moved in a heave show a distinct peak in propulsive performance, while the addition of pitch input produces a broad plateau where the swimming speed is relatively unaffected by the flexural stiffness. Our understanding of the material design of fish and the control of tissue

  12. Colonization of abandoned swimming pools by larval mosquitoes and their predators following Hurricane Katrina.

    PubMed

    Caillouët, Kevin A; Carlson, John C; Wesson, Dawn; Jordan, Frank

    2008-06-01

    Thousands of flooded swimming pools were abandoned in New Orleans following Hurricane Katrina and provided a natural experiment to examine colonization of a novel aquatic habitat by mosquito larvae and their aquatic predators. We conducted a randomized survey of flooded swimming pools in two neighborhoods in January 2006 and found that 64% contained mosquito larvae, 92% contained predatory invertebrates, and 47% contained fishes. We collected 12,379 immature mosquitoes representing five species, primarily Culiseta inornata, and secondarily, the arboviral vector Culex quinquefasciatus. Dragonfly nymphs in the families Aeshnidae and Libellulidae were the most common predatory invertebrates collected among a total of 32 non-mosquito invertebrate species. Eleven species of fishes were collected, with Gambusia affinis accounting for 76% of the catch. Diversity of fishes in swimming pools was positively correlated with proximity to a levee breach and the fish assemblage found in swimming pools was similar to that found along shorelines of Lake Pontchartrain and drainage canals that flooded the study area. Mosquito larvae were rare or absent from pools containing fishes; however, path analysis indicated that the presence of top predators or abundant competitors may somewhat mitigate the effect of Gambusia affinis on mosquito presence. PMID:18697320

  13. Visualization on fish's wake

    NASA Astrophysics Data System (ADS)

    Li, Xuemin; Lu, Xiyun; Yin, Xiezhen

    2002-05-01

    In this paper an experiment on wake of Goldfish swimming unrestricted was conducted in a water tunnel. Method of color liquid was used to visualize the wake. Results show that there is reverse Karman vortex street in symmetrical plane of the wake and the Strouhal frequency of the fish is in the range 0.25-0.35. A 3D vortex ring chain model was presented.

  14. Flow disturbances generated by feeding and swimming zooplankton

    PubMed Central

    Kiørboe, Thomas; Jiang, Houshuo; Gonçalves, Rodrigo Javier; Nielsen, Lasse Tor; Wadhwa, Navish

    2014-01-01

    Interactions between planktonic organisms, such as detection of prey, predators, and mates, are often mediated by fluid signals. Consequently, many plankton predators perceive their prey from the fluid disturbances that it generates when it feeds and swims. Zooplankton should therefore seek to minimize the fluid disturbance that they produce. By means of particle image velocimetry, we describe the fluid disturbances produced by feeding and swimming in zooplankton with diverse propulsion mechanisms and ranging from 10-µm flagellates to greater than millimeter-sized copepods. We show that zooplankton, in which feeding and swimming are separate processes, produce flow disturbances during swimming with a much faster spatial attenuation (velocity u varies with distance r as u ∝ r−3 to r−4) than that produced by zooplankton for which feeding and propulsion are the same process (u ∝ r−1 to r−2). As a result, the spatial extension of the fluid disturbance produced by swimmers is an order of magnitude smaller than that produced by feeders at similar Reynolds numbers. The “quiet” propulsion of swimmers is achieved either through swimming erratically by short-lasting power strokes, generating viscous vortex rings, or by “breast-stroke swimming.” Both produce rapidly attenuating flows. The more “noisy” swimming of those that are constrained by a need to simultaneously feed is due to constantly beating flagella or appendages that are positioned either anteriorly or posteriorly on the (cell) body. These patterns transcend differences in size and taxonomy and have thus evolved multiple times, suggesting a strong selective pressure to minimize predation risk. PMID:25071196

  15. Flow disturbances generated by feeding and swimming zooplankton.

    PubMed

    Kiørboe, Thomas; Jiang, Houshuo; Gonçalves, Rodrigo Javier; Nielsen, Lasse Tor; Wadhwa, Navish

    2014-08-12

    Interactions between planktonic organisms, such as detection of prey, predators, and mates, are often mediated by fluid signals. Consequently, many plankton predators perceive their prey from the fluid disturbances that it generates when it feeds and swims. Zooplankton should therefore seek to minimize the fluid disturbance that they produce. By means of particle image velocimetry, we describe the fluid disturbances produced by feeding and swimming in zooplankton with diverse propulsion mechanisms and ranging from 10-µm flagellates to greater than millimeter-sized copepods. We show that zooplankton, in which feeding and swimming are separate processes, produce flow disturbances during swimming with a much faster spatial attenuation (velocity u varies with distance r as u ∝ r(-3) to r(-4)) than that produced by zooplankton for which feeding and propulsion are the same process (u ∝ r(-1) to r(-2)). As a result, the spatial extension of the fluid disturbance produced by swimmers is an order of magnitude smaller than that produced by feeders at similar Reynolds numbers. The "quiet" propulsion of swimmers is achieved either through swimming erratically by short-lasting power strokes, generating viscous vortex rings, or by "breast-stroke swimming." Both produce rapidly attenuating flows. The more "noisy" swimming of those that are constrained by a need to simultaneously feed is due to constantly beating flagella or appendages that are positioned either anteriorly or posteriorly on the (cell) body. These patterns transcend differences in size and taxonomy and have thus evolved multiple times, suggesting a strong selective pressure to minimize predation risk. PMID:25071196

  16. Effect of Erabu sea snake (Laticauda semifasciata) lipids on the swimming endurance of aged mice.

    PubMed

    Zhang, Guihua; Shirai, Nobuya; Higuchi, Tomoyuki; Suzuki, Hiramitsu; Shimizu, Eiji

    2007-12-01

    The effect of Erabu sea snake (Laticauda semifasciata) lipids on the swimming endurance was investigated in aged mice. Fifty three-week-old male Crlj:CD-1 (ICR) mice were fed one of three experimental diets containing either 6% lard, 6% fish oil, or 6% sea snake lipids for 16 wk. The swimming exercise was carried out in an acrylic plastic tank filled with 25 cm of water maintained at 23(o)C. Swimming times to exhaustion were measured with a load of 2% of their body weights attached to the tails of the mice. The swimming times to exhaustion of the group that were fed the sea snake lipid diet tended to be longer than those of the lard diet group, and were significantly improved compared with the fish oil diet group (p<0.05). The plasma and muscle lactate levels were significantly lower in the sea snake lipid diet group than in the lard and fish oil diet groups (p<0.05). The liver glycogen and plasma glucose levels of the sea snake lipid diet group did not differ markedly from those of the lard diet group (p>0.05), and were significantly higher than those of the fish oil diet group (p<0.05). These results suggest that an intake of sea snake lipids but not the fish oil, which is also rich in n-3 polyunsaturated fatty acids (n-3 PUFAs), is useful for improving the swimming endurance of aged mice by attenuating lactate production and/or enhancing lactate clearance during swimming exercise, and the n-3 PUFAs contained in the sea snake lipids did little or nothing for this improved endurance. PMID:18202534

  17. Labriform swimming of a ray-strengthened pectoral fin

    NASA Astrophysics Data System (ADS)

    Shoele, Kourosh; Zhu, Qiang

    2009-11-01

    Labriform swimming is a common locomotion mode used by fish in low speed swimming, in which thrust generation is achieved through a combination of flapping and rowing motions of pectoral fins. Pectoral fins of bony fishes usually consist of a soft collagen membrane strengthened by embedded flexible rays. Morphologically, each ray is connected to a group of muscles so that the fish can control the rotational motion of each ray individually, enabling multi-degree of freedom control over the fin motion and deformation. We have developed a fluid-structure interaction model to simulate the kinematics and dynamic performance of a structurally idealized fin. This method includes a boundary-element model of the fluid motion and a fully-nonlinear Euler-Bernoulli beam model of the embedded rays. Using this model we studied thrust generation and propulsion efficiency of the fin at different combinations of parameters. Effects of kinematic as well as structural properties are examined. It has been illustrated that the fish's capacity to control the motion of each individual ray, as well as the anisotropic deformability of the fin determined by distribution of the rays, are essential to high propulsion performance. Specifically, it is found that a reinforced ray at the leading edge leads to performance enhancement.

  18. Steps of Healthy Swimming: Protection against Recreational Water Illnesses (RWIs)

    MedlinePlus

    ... Work: Healthy Swimming Policy & Recommendations Fast Facts Healthy Water Sites Healthy Water Drinking Water Healthy Swimming Global ... has moved to Steps of Healthy Swimming. Healthy Water Sites Healthy Water Drinking Water Healthy Swimming Global ...

  19. Paramecium swimming in capillary tube

    NASA Astrophysics Data System (ADS)

    Jana, Saikat; Um, Soong Ho; Jung, Sunghwan

    2012-04-01

    Swimming organisms in their natural habitat need to navigate through a wide range of geometries and chemical environments. Interaction with boundaries in such situations is ubiquitous and can significantly modify the swimming characteristics of the organism when compared to ideal laboratory conditions. We study the different patterns of ciliary locomotion in glass capillaries of varying diameter and characterize the effect of the solid boundaries on the velocities of the organism. Experimental observations show that Paramecium executes helical trajectories that slowly transition to straight lines as the diameter of the capillary tubes decreases. We predict the swimming velocity in capillaries by modeling the system as a confined cylinder propagating longitudinal metachronal waves that create a finite pressure gradient. Comparing with experiments, we find that such pressure gradient considerations are necessary for modeling finite sized ciliary organisms in restrictive geometries.

  20. Optimal swimming of a sheet

    NASA Astrophysics Data System (ADS)

    Montenegro-Johnson, Thomas D.; Lauga, Eric

    2014-06-01

    Propulsion at microscopic scales is often achieved through propagating traveling waves along hairlike organelles called flagella. Taylor's two-dimensional swimming sheet model is frequently used to provide insight into problems of flagellar propulsion. We derive numerically the large-amplitude wave form of the two-dimensional swimming sheet that yields optimum hydrodynamic efficiency: the ratio of the squared swimming speed to the rate-of-working of the sheet against the fluid. Using the boundary element method, we show that the optimal wave form is a front-back symmetric regularized cusp that is 25% more efficient than the optimal sine wave. This optimal two-dimensional shape is smooth, qualitatively different from the kinked form of Lighthill's optimal three-dimensional flagellum, not predicted by small-amplitude theory, and different from the smooth circular-arc-like shape of active elastic filaments.

  1. Influence of robotic shoal size, configuration, and activity on zebrafish behavior in a free-swimming environment.

    PubMed

    Butail, Sachit; Polverino, Giovanni; Phamduy, Paul; Del Sette, Fausto; Porfiri, Maurizio

    2014-12-15

    In animal studies, robots have been recently used as a valid tool for testing a wide spectrum of hypotheses. These robots often exploit visual or auditory cues to modulate animal behavior. The propensity of zebrafish, a model organism in biological studies, toward fish with similar color patterns and shape has been leveraged to design biologically inspired robots that successfully attract zebrafish in preference tests. With an aim of extending the application of such robots to field studies, here, we investigate the response of zebrafish to multiple robotic fish swimming at different speeds and in varying arrangements. A soft real-time multi-target tracking and control system remotely steers the robots in circular trajectories during the experimental trials. Our findings indicate a complex behavioral response of zebrafish to biologically inspired robots. More robots produce a significant change in salient measures of stress, with a fast robot swimming alone causing more freezing and erratic activity than two robots swimming slowly together. In addition, fish spend more time in the proximity of a robot when they swim far apart than when the robots swim close to each other. Increase in the number of robots also significantly alters the degree of alignment of fish motion with a robot. Results from this study are expected to advance our understanding of robot perception by live animals and aid in hypothesis-driven studies in unconstrained free-swimming environments. PMID:25239605

  2. Study of fish response using particle image velocimetry and high-speed, high-resolution imaging

    SciTech Connect

    Deng, Z.; Richmond, M. C.; Mueller, R. P.; Gruensch, G. R.

    2004-10-01

    Fish swimming has fascinated both engineers and fish biologists for decades. Digital particle image velocimetry (DPIV) and high-speed, high-resolution digital imaging are recently developed analysis tools that can help engineers and biologists better understand how fish respond to turbulent environments. This report details studies to evaluate DPIV. The studies included a review of existing literature on DPIV, preliminary studies to test the feasibility of using DPIV conducted at our Flow Biology Laboratory in Richland, Washington September through December 2003, and applications of high-speed, high-resolution digital imaging with advanced motion analysis to investigations of fish injury mechanisms in turbulent shear flows and bead trajectories in laboratory physical models. Several conclusions were drawn based on these studies, which are summarized as recommendations for proposed research at the end of this report.

  3. Reduction in swimming performance in juvenile rainbow trout (Oncorhynchus mykiss) following sublethal exposure to pyrethroid insecticides.

    PubMed

    Goulding, Adam T; Shelley, Lesley K; Ross, Peter S; Kennedy, Christopher J

    2013-04-01

    While the lethal toxicity of pyrethroid insecticides to fish is well documented, their sublethal physio-behavioral effects remain poorly characterized. Known pyrethroid-associated changes to insect neuromuscular function may translate into similar effects in fish, thereby altering swimming ability and affecting foraging, predator avoidance, and migration. Three experiments were conducted using critical (Ucrit) and burst (Umax) swimming speeds to assess the sublethal effects of the pyrethroids permethrin and deltamethrin in juvenile rainbow trout (Oncorhynchus mykiss). Fish were exposed to deltamethrin (100, 200, or 300 ng/L) or permethrin (1, 2, or 3 μg/L) in water for 4 d, and assessed for swimming performance. Deltamethrin (200 and 300 ng/L) reduced Ucrit, but not Umax, while both swim performance measurements were unaffected by permethrin. Subsequent experiments used only Ucrit to assess deltamethrin exposure. In a time course experiment, deltamethrin (300 ng/L) reduced Ucrit after 1 and 4 d of exposure, but after 7 d of exposure Ucrit was fully recovered. Finally, deltamethrin (1, 2, or 3 μg/L) reduced Ucrit after 1h bath exposures similar to recommended protocols for deltamethrin based sea-lice treatment in aquaculture. The real-world implications of the revealed pyrethroid-associated swimming ability reductions in salmon may be important in areas close to aquaculture facilities. PMID:23318297

  4. Interactions between internal forces, body stiffness, and fluid environment in a neuromechanical model of lamprey swimming

    PubMed Central

    Tytell, Eric D.; Hsu, Chia-Yu; Williams, Thelma L.; Cohen, Avis H.; Fauci, Lisa J.

    2010-01-01

    Animal movements result from a complex balance of many different forces. Muscles produce force to move the body; the body has inertial, elastic, and damping properties that may aid or oppose the muscle force; and the environment produces reaction forces back on the body. The actual motion is an emergent property of these interactions. To examine the roles of body stiffness, muscle activation, and fluid environment for swimming animals, a computational model of a lamprey was developed. The model uses an immersed boundary framework that fully couples the Navier–Stokes equations of fluid dynamics with an actuated, elastic body model. This is the first model at a Reynolds number appropriate for a swimming fish that captures the complete fluid-structure interaction, in which the body deforms according to both internal muscular forces and external fluid forces. Results indicate that identical muscle activation patterns can produce different kinematics depending on body stiffness, and the optimal value of stiffness for maximum acceleration is different from that for maximum steady swimming speed. Additionally, negative muscle work, observed in many fishes, emerges at higher tail beat frequencies without sensory input and may contribute to energy efficiency. Swimming fishes that can tune their body stiffness by appropriately timed muscle contractions may therefore be able to optimize the passive dynamics of their bodies to maximize peak acceleration or swimming speed. PMID:21037110

  5. 43 CFR 423.36 - Swimming.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Swimming. (a) You may swim, wade, snorkel, scuba dive, raft, or tube at your own risk in Reclamation waters... Guard guidelines when engaging in any underwater activities. (c) You must not dive, jump, or swing...

  6. 43 CFR 423.36 - Swimming.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Swimming. (a) You may swim, wade, snorkel, scuba dive, raft, or tube at your own risk in Reclamation waters... Guard guidelines when engaging in any underwater activities. (c) You must not dive, jump, or swing...

  7. 43 CFR 423.36 - Swimming.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Swimming. (a) You may swim, wade, snorkel, scuba dive, raft, or tube at your own risk in Reclamation waters... Guard guidelines when engaging in any underwater activities. (c) You must not dive, jump, or swing...

  8. 43 CFR 423.36 - Swimming.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Swimming. (a) You may swim, wade, snorkel, scuba dive, raft, or tube at your own risk in Reclamation waters... Guard guidelines when engaging in any underwater activities. (c) You must not dive, jump, or swing...

  9. 43 CFR 423.36 - Swimming.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Swimming. (a) You may swim, wade, snorkel, scuba dive, raft, or tube at your own risk in Reclamation waters... Guard guidelines when engaging in any underwater activities. (c) You must not dive, jump, or swing...

  10. Effects of Drying Temperature on Barrier and Mechanical Properties of Cold-Water Fish Gelatin Films

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fish gelatin films made from Alaska pollock (Theragra chalcogramma) and Alaska pink salmon (Oncorhynchus gorbuscha) were dried at 4C, 23C, 40C, and 60C. The tensile, thermal, thermal stability, water sorption, and water vapor permeability properties were examined for cold-cast gelatin films (dried b...

  11. Solar Wind Monitoring with SWIM-SARA Onboard Chandrayaan-1

    NASA Astrophysics Data System (ADS)

    Bhardwaj, A.; Barabash, S.; Sridharan, R.; Wieser, M.; Dhanya, M. B.; Futaana, Y.; Asamura, K.; Kazama, Y.; McCann, D.; Varier, S.; Vijayakumar, E.; Mohankumar, S. V.; Raghavendra, K. V.; Kurian, T.; Thampi, R. S.; Andersson, H.; Svensson, J.; Karlsson, S.; Fischer, J.; Holmstrom, M.; Wurz, P.; Lundin, R.

    The SARA experiment aboard the Indian lunar mission Chandrayaan-1 consists of two instruments: Chandrayaan-1 Energetic Neutral Analyzer (CENA) and the SolarWind Monitor (SWIM). CENA will provide measurements of low energy neutral atoms sputtered from lunar surface in the 0.01-3.3 keV energy range by the impact of solar wind ions. SWIM will monitor the solar wind flux precipitating onto the lunar surface and in the vicinity of moon. SWIM is basically an ion-mass analyzer providing energy-per-charge and number density of solar wind ions in the energy range 0.01-15 keV. It has sufficient mass resolution to resolve H+ , He++, He+, O++, O+, and >20 amu, with energy resolution 7% and angular resolution 4:5° × 22:5. The viewing angle of the instrument is 9° × 180°.Mechanically, SWIM consists of a sensor and an electronic board that includes high voltage supply and sensor electronics. The sensor part consists of an electrostatic deflector to analyze the arrival angle of the ions, cylindrical electrostatic analyzer for energy analysis, and the time-of-flight system for particle velocity determination. The total size of SWIM is slightly larger than a credit card and has a mass of 500 g.

  12. Fish robotics and hydrodynamics

    NASA Astrophysics Data System (ADS)

    Lauder, George

    2010-11-01

    Studying the fluid dynamics of locomotion in freely-swimming fishes is challenging due to difficulties in controlling fish behavior. To provide better control over fish-like propulsive systems we have constructed a variety of fish-like robotic test platforms that range from highly biomimetic models of fins, to simple physical models of body movements during aquatic locomotion. First, we have constructed a series of biorobotic models of fish pectoral fins with 5 fin rays that allow detailed study of fin motion, forces, and fluid dynamics associated with fin-based locomotion. We find that by tuning fin ray stiffness and the imposed motion program we can produce thrust both on the fin outstroke and instroke. Second, we are using a robotic flapping foil system to study the self-propulsion of flexible plastic foils of varying stiffness, length, and trailing edge shape as a means of investigating the fluid dynamic effect of simple changes in the properties of undulating bodies moving through water. We find unexpected non-linear stiffness-dependent effects of changing foil length on self-propelled speed, and as well as significant effects of trailing edge shape on foil swimming speed.

  13. 1968 Listing of Swimming Pool Equipment.

    ERIC Educational Resources Information Center

    National Sanitation Foundation, Ann Arbor, MI. Testing Lab.

    An up-to-date listing of swimming pool equipment including--(1) companies authorized to display the National Sanitation Foundation seal of approval, (2) equipment listed as meeting NSF swimming pool equipment standards relating to diatomite type filters, (3) equipment listed as meeting NSF swimming pool equipment standard relating to sand type…

  14. 36 CFR 327.5 - Swimming.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 3 2013-07-01 2012-07-01 true Swimming. 327.5 Section 327.5 Parks, Forests, and Public Property CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY RULES AND REGULATIONS GOVERNING PUBLIC USE OF WATER RESOURCE DEVELOPMENT PROJECTS ADMINISTERED BY THE CHIEF OF ENGINEERS § 327.5 Swimming. (a) Swimming, wading,...

  15. 36 CFR 327.5 - Swimming.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 3 2012-07-01 2012-07-01 false Swimming. 327.5 Section 327.5 Parks, Forests, and Public Property CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY RULES AND REGULATIONS GOVERNING PUBLIC USE OF WATER RESOURCE DEVELOPMENT PROJECTS ADMINISTERED BY THE CHIEF OF ENGINEERS § 327.5 Swimming. (a) Swimming,...

  16. The Effect of Swimming Experience on Acquisition and Retention of Swimming-Based Taste Aversion Learning in Rats

    ERIC Educational Resources Information Center

    Masaki, Takahisa; Nakajima, Sadahiko

    2010-01-01

    Swimming endows rats with an aversion to a taste solution consumed before swimming. The present study explored whether the experience of swimming before or after the taste-swimming trials interferes with swimming-based taste aversion learning. Experiment 1 demonstrated that a single preexposure to 20 min of swimming was as effective as four or…

  17. Sports Medicine Meets Synchronized Swimming.

    ERIC Educational Resources Information Center

    Wenz, Betty J.; And Others

    This collection of articles contains information about synchronized swimming. Topics covered include general physiology and cardiovascular conditioning, flexibility exercises, body composition, strength training, nutrition, coach-athlete relationships, coping with competition stress and performance anxiety, and eye care. Chapters are included on…

  18. Swimming pool-induced asthma.

    PubMed

    Beretta, S; Vivaldo, T; Morelli, M; Carlucci, P; Zuccotti, G V

    2011-01-01

    A 13-year-old elite swimmer presented with wheezing after indoor swimming training. On the basis of her clinical history and the tests performed, exercise-induced asthma and mold-induced asthma were ruled out and a diagnosis of chlorine-induced asthma was made. PMID:21548454

  19. Swimming and Campylobacter Infections1

    PubMed Central

    Schönberg-Norio, Daniela; Takkinen, Johanna; Hänninen, Marja-Liisa; Katila, Marja-Leena; Kaukoranta, Suvi-Sirkku; Mattila, Leena

    2004-01-01

    A matched case-control study was conducted to study risk factors for domestically acquired sporadic Campylobacter infections in Finland. Swimming in natural sources of water was a novel risk factor. Eating undercooked meat and drinking dug-well water were also independent risk factors for Campylobacter infection. PMID:15496253

  20. The effects of chronic cadmium exposure on repeat swimming performance and anaerobic metabolism in brown trout (Salmo trutta) and lake whitefish (Coregonus clupeaformis).

    PubMed

    Cunningham, Jessie L; McGeer, James C

    2016-04-01

    This study investigates the effect of chronic Cd exposure on the ability to perform repeat swim challenges in brown trout (Salmo trutta) and lake whitefish (Coregonus clupeaformis). Fish were exposed to waterborne Cd (18nM) in moderately hard water (120mgL(-1) CaCO3) for 30 days. This level of exposure has been shown to cause sublethal physiological disruption and acclimation responses but no impairment of sustained swimming capacity (Ucrit) in single swim challenges. Swim trials were done over the course of the exposure and each one consisted of an initial swim to 85% of the Ucrit of control fish, a 30min recovery period and finally a second swim challenge to determine Ucrit. Plasma and tissue samples were collected before and after each of the swim periods. As expected from previous studies, Cd exposure resulted in significant accumulation of Cd in gills, liver and kidney but not in white muscle. Exposure also induced a loss of plasma Ca followed by subsequent recovery (in lake whitefish but not brown trout) with few mortalities (100% survival for lake whitefish and 93% for brown trout). Both control and exposed fish swam to 85% of the single swim Ucrit and no differences in performance were seen. The Ucrit of unexposed controls in the second swim challenges were not different from the single swim Ucrit. However, second swim performance was significantly reduced in Cd exposed fish, particularly after a week of exposure where 31% and 38% reductions were observed for brown trout and lake whitefish respectively. Swimming to 85% Ucrit resulted in metabolic expenditure with little recovery after 30min. Few differences were observed between control and Cd exposed fish with the exception of a reduction in resting white muscle ATP stores of Cd exposed fish after 1 week of exposure. The results show that chronic sublethal Cd exposure results in an impairment of swimming ability in repeat swim challenges but this impairment is generally not related to metabolic processes

  1. Genome Sequencing of the Perciform Fish Larimichthys crocea Provides Insights into Molecular and Genetic Mechanisms of Stress Adaptation

    PubMed Central

    Shi, Qiong; Zhu, Lv-Yun; Li, Ting; Ding, Yang; Nie, Li; Li, Qiuhua; Dong, Wei-ren; Jiang, Liang; Sun, Bing; Zhang, XinHui; Li, Mingyu; Zhang, Hai-Qi; Xie, ShangBo; Zhu, YaBing; Jiang, XuanTing; Wang, Xianhui; Mu, Pengfei; Chen, Wei; Yue, Zhen; Wang, Zhuo; Wang, Jun; Shao, Jian-Zhong; Chen, Xinhua

    2015-01-01

    The large yellow croaker Larimichthys crocea (L. crocea) is one of the most economically important marine fish in China and East Asian countries. It also exhibits peculiar behavioral and physiological characteristics, especially sensitive to various environmental stresses, such as hypoxia and air exposure. These traits may render L. crocea a good model for investigating the response mechanisms to environmental stress. To understand the molecular and genetic mechanisms underlying the adaptation and response of L. crocea to environmental stress, we sequenced and assembled the genome of L. crocea using a bacterial artificial chromosome and whole-genome shotgun hierarchical strategy. The final genome assembly was 679 Mb, with a contig N50 of 63.11 kb and a scaffold N50 of 1.03 Mb, containing 25,401 protein-coding genes. Gene families underlying adaptive behaviours, such as vision-related crystallins, olfactory receptors, and auditory sense-related genes, were significantly expanded in the genome of L. crocea relative to those of other vertebrates. Transcriptome analyses of the hypoxia-exposed L. crocea brain revealed new aspects of neuro-endocrine-immune/metabolism regulatory networks that may help the fish to avoid cerebral inflammatory injury and maintain energy balance under hypoxia. Proteomics data demonstrate that skin mucus of the air-exposed L. crocea had a complex composition, with an unexpectedly high number of proteins (3,209), suggesting its multiple protective mechanisms involved in antioxidant functions, oxygen transport, immune defence, and osmotic and ionic regulation. Our results reveal the molecular and genetic basis of fish adaptation and response to hypoxia and air exposure. The data generated by this study will provide valuable resources for the genetic improvement of stress resistance and yield potential in L. crocea. PMID:25835551

  2. A neural mechanism of hyperaccurate detection of phase advance and delay in the jamming avoidance response of weakly electric fish.

    PubMed

    Kashimori, Y; Inoue, S; Kambara, T

    2001-08-01

    The weakly electric fish Eigenmannia can detect the phase difference between a jamming signal and its own signal down to micros. To clarify the neuronal mechanism of this hyperaccurate detection of phase difference, we present a neural network model of the torus of the midbrain which plays an essential role in the detection of phase advances and delays. The small-cell model functions as a coincidence detector and can discriminate a time difference of more than 100 micros. The torus model consists of laminae 6 and 8. The model of lamina 6 is made with multiple encoding units, each of which consists of a single linear array of small cells and a single giant cell. The encoding unit encodes the phase difference into its spatio-temporal firing pattern. The spatially random distribution of small cells in each encoding unit improves the encoding ability of phase modulation. The neurons in lamina 8 can discriminate the phase advance and delay of jamming electric organ discharges (EODs) compared with the phase of the fish's own EOD by integrating simultaneously the outputs from multiple encoding units in lamina 6. The discrimination accuracy of the feature-detection neurons is of the order of 1 micros. The neuronal mechanism generating this hyperacuity arises from the spatial feature of the system that the innervation sites of small cells in different encoding units are distributed randomly and differently on the dendrites of single feature-detection neurons. The mechanism is similar to that of noise-enhanced information transmission. PMID:11508775

  3. Ultraviolet absorbing compounds provide a rapid response mechanism for UV protection in some reef fish.

    PubMed

    Braun, C; Reef, R; Siebeck, U E

    2016-07-01

    The external mucus surface of reef fish contains ultraviolet absorbing compounds (UVAC), most prominently Mycosporine-like Amino Acids (MAAs). MAAs in the external mucus of reef fish are thought to act as sunscreens by preventing the damaging effects of ultraviolet radiation (UVR), however, direct evidence for their protective role has been missing. We tested the protective function of UVAC's by exposing fish with naturally low, Pomacentrus amboinensis, and high, Thalassoma lunare, mucus absorption properties to a high dose of UVR (UVB: 13.4W∗m(-2), UVA: 6.1W∗m(-2)) and measuring the resulting DNA damage in the form of cyclobutane pyrimidine dimers (CPDs). For both species, the amount of UV induced DNA damage sustained following the exposure to a 1h pulse of high UVR was negatively correlated with mucus absorbance, a proxy for MAA concentration. Furthermore, a rapid and significant increase in UVAC concentration was observed in P. amboinensis following UV exposure, directly after capture and after ten days in captivity. No such increase was observed in T. lunare, which maintained relatively high levels of UV absorbance at all times. P. amboinensis, in contrast to T. lunare, uses UV communication and thus must maintain UV transparent mucus to be able to display its UV patterns. The ability to rapidly alter the transparency of mucus could be an important adaptation in the trade off between protection from harmful UVR and UV communication. PMID:27162066

  4. Central mechanisms of temporal analysis in the knollenorgan pathway of mormyrid electric fish

    PubMed

    Xu-Friedman; Hopkins

    1999-05-01

    Mormyrid electric fish communicate using pulse-type electric organ discharges (EODs). The fine temporal structure of the waveforms of EODs varies widely throughout the 200 or more species of mormyrids. These signals carry information about the species, the sex and even the individual identity of the signaller. Behavioral experiments have shown that some species of fish are capable of using this information. Of the four known types of electroreceptors in mormyrid fish, the knollenorgan electroreceptor is the one most likely to be involved in the detection of conspecific EOD signals. Here, we review some recent advances in understanding how the central knollenorgan pathway might be analyzing the temporal structure of the EOD waveform. Fine temporal analysis appears to take place in the nucleus exterolateralis pars anterior (ELa), where tightly phase-locked inputs from the hindbrain drive a direct, excitatory input through a long axonal delay line and also drive an indirect, inhibitory input with negligible delay through the ELa large cell. These two inputs converge on ELa small cells, where they are hypothesized to interact in a 'delay-line/blanking' model. This initial temporal analysis is further refined in the nucleus exterolateralis pars posterior, where units tuned to ranges of pulse durations have been identified physiologically. PMID:10210671

  5. Suspension biomechanics of swimming microbes

    PubMed Central

    Ishikawa, Takuji

    2009-01-01

    Micro-organisms play a vital role in many biological, medical and engineering phenomena. Some recent research efforts have demonstrated the importance of biomechanics in understanding certain aspects of micro-organism behaviours such as locomotion and collective motions of cells. In particular, spatio-temporal coherent structures found in a bacterial suspension have been the focus of many research studies over the last few years. Recent studies have shown that macroscopic properties of a suspension, such as rheology and diffusion, are strongly affected by meso-scale flow structures generated by swimming microbes. Since the meso-scale flow structures are strongly affected by the interactions between microbes, a bottom-up strategy, i.e. from a cellular level to a continuum suspension level, represents the natural approach to the study of a suspension of swimming microbes. In this paper, we first provide a summary of existing biomechanical research on interactions between a pair of swimming micro-organisms, as a two-body interaction is the simplest many-body interaction. We show that interactions between two nearby swimming micro-organisms are described well by existing mathematical models. Then, collective motions formed by a group of swimming micro-organisms are discussed. We show that some collective motions of micro-organisms, such as coherent structures of bacterial suspensions, are satisfactorily explained by fluid dynamics. Lastly, we discuss how macroscopic suspension properties are changed by the microscopic characteristics of the cell suspension. The fundamental knowledge we present will be useful in obtaining a better understanding of the behaviour of micro-organisms. PMID:19674997

  6. Chronic perchlorate exposure impairs stickleback reproductive behaviour and swimming performance

    PubMed Central

    Bernhardt, Richard R.; von Hippel, Frank A.

    2011-01-01

    Summary We describe behavioural changes in two generations of threespine stickleback (Gasterosteus aculeatus) exposed to environmentally relevant concentrations of perchlorate. The first generation (G0,2002) was exposed as two-year-old adults to perchlorate in experimental groups ranging in concentration from less than the method detection limit (<1.1 ppb) to 18.6 ppm for up to 22 days during their courtship, spawning, egg guarding, and first five days of fry guarding. No differences were noted in the behaviour or reproductive output of these fish that were exposed as adults. However, perchlorate exposure throughout development caused widespread effects in the second generation (G1,2003), which was spawned and raised through sexual maturity in one of four nominal experimental groups (0, 30 and 100 ppm, and a ‘variable’ treatment that progressively increased from <1.1 ppb to approximately 60 ppm perchlorate). Dose-dependent effects were found during the G1,2003’s swimming and behavioural evaluations, including higher mortality rates among treated fish following stressful events. Perchlorate-exposed fish had higher failure rates during swimming trials and failed at lower flow rates than control fish. A number of treated fish exhibited seizures. Progressively fewer males completed benchmark metrics, such as nest building, spawning, nursery formation, or fry production, in a dose-dependent manner. Fewer males from higher treatments courted females, and those that did initiated courtship later and had a reduced behavioural repertoire compared to fish from lower treatments. The lowest observed adverse effect level (LOAEL) for swimming performance, reproductive behaviour, survivorship and recruitment was 30 ppm perchlorate (our lowest G1,2003 treatment), and near complete inhibition of reproductive activity was noted among males raised in 100 ppm perchlorate. A small number of treated G1,2003 females were isolated in aquaria, and some performed reproductive

  7. Streamwise vortices destabilize swimming bluegill sunfish (Lepomis macrochirus).

    PubMed

    Maia, Anabela; Sheltzer, Alex P; Tytell, Eric D

    2015-03-01

    In their natural environment, fish must swim stably through unsteady flows and vortices, including vertical vortices, typically shed by posts in a flow, horizontal cross-flow vortices, often produced by a step or a waterfall in a stream, and streamwise vortices, where the axis of rotation is aligned with the direction of the flow. Streamwise vortices are commonly shed by bluff bodies in streams and by ships' propellers and axial turbines, but we know little about their effects on fish. Here, we describe how bluegill sunfish use more energy and are destabilized more often in flow with strong streamwise vorticity. The vortices were created inside a sealed flow tank by an array of four turbines with similar diameter to the experimental fish. We measured oxygen consumption for seven sunfish swimming at 1.5 body lengths (BL) s(-1) with the turbines rotating at 2 Hz and with the turbines off (control). Simultaneously, we filmed the fish ventrally and recorded the fraction of time spent maneuvering side-to-side and accelerating forward. Separately, we also recorded lateral and ventral video for a combination of swimming speeds (0.5, 1.5 and 2.5 BL s(-1)) and turbine speeds (0, 1, 2 and 3 Hz), immediately after turning the turbines on and 10 min later to test for accommodation. Bluegill sunfish are negatively affected by streamwise vorticity. Spills (loss of heading), maneuvers and accelerations were more frequent when the turbines were on than in the control treatment. These unsteady behaviors, particularly acceleration, correlated with an increase in oxygen consumption in the vortex flow. Bluegill sunfish are generally fast to recover from roll perturbations and do so by moving their pectoral fins. The frequency of spills decreased after the turbines had run for 10 min, but was still markedly higher than in the control, showing that fish partially adapt to streamwise vorticity, but not completely. Coping with streamwise vorticity may be an important energetic

  8. Injection of Resperpine into Zebrafish, Prevents Fish to Fish Communication of Radiation-Induced Bystander Signals: Confirmation in Vivo of a Role for Serotonin in the Mechanism

    PubMed Central

    Saroya, Rohin; Smith, Richard; Seymour, Colin; Mothersill, Carmel

    2009-01-01

    Serotonin (5-HT) has been implicated as a potential modulator of the bystander effect in cell cultures. To assess the relevance of serotonin in vivo experiments were done with the zebrafish (Danio rerio). This species, when irradiated, transmits bystander signals to non-irradiated fish. The animals were injected with reserpine, an inhibitor of serotonin at a dose of 80mg/kg of body mass. The results show that reserpine treated fish had only 27% of the serotonin in non-treated fish. Skin tissue samples were collected from the fish and assayed for bystander signal production using a reporter bioassay. Reserpine prevented the production and communication of signals between fish. Intracellular calcium flux, identified as a bystander response in the reporter cells confirmed this. Medium harvested from tissues of X-rayed fish and their bystanders, showed an oscillating pattern of calcium flux. Samples from X-rayed fish pretreated with reserpine produced a chaotic pattern of random fluctuations in the reporter cells, while their bystander fish led to increased calcium, but no oscillations. These results suggest that 5-HT is involved in bystander signalling in zebrafish, and by decreasing the amount of available 5-HT the bystander effect can be blocked. PMID:20877486

  9. Effect of horizontal strong static magnetic field on swimming behaviour of Paramecium caudatum

    NASA Astrophysics Data System (ADS)

    Fujiwara, Yoshihisa; Tomishige, Masahiko; Itoh, Yasuhiro; Fujiwara, Masao; Shibata, Naho; Kosaka, Toshikazu; Hosoya, Hiroshi; Tanimoto, Yoshifumi

    2006-05-01

    Effect of horizontal strong static magnetic field on swimming behaviour of Paramecium caudatum was studied by using a superconducting magnet. Around a centre of a round vessel, random swimming at 0 T and aligned swimming parallel to the magnetic field (MF) of 8 T were observed. Near a wall of the vessel, however, swimming round and round along the wall at 0 T and aligned swimming of turning at right angles upon collision with the wall, which was remarkable around 1-4 T, were detected. It was experimentally revealed that the former MF-induced parallel swimming at the vessel centre was caused physicochemically by the parallel magnetic orientation of the cell itself. From magnetic field dependence of the extent of the orientation, the magnetic susceptibility anisotropy (χ ∥-χ ⊥) was first obtained to be 3.4× 10-23 emu cell-1 at 298 K for Paramecium caudatum. The orientation of the cell was considered to result from the magnetic orientation of the cell membrane. On the other hand, although mechanisms of the latter swimming near the vessel wall regardless of the absence and presence of the magnetic field are unclear at present, these experimental results indicate that whether the cell exists near the wall alters the magnetic field effect on the swimming in the horizontal magnetic field.

  10. Effect of swimming intensity on subsequent cycling and overall triathlon performance

    PubMed Central

    Peeling, P; Bishop, D; Landers, G; Boone, T

    2005-01-01

    Objectives: To investigate the effects of different swimming intensities on subsequent cycling and overall triathlon performance. Methods: Nine highly trained, male triathletes completed five separate laboratory sessions comprising one graded exercise test, a swim time trial (STT), and three sprint distance triathlons (TRI). The swimming velocities of the three TRI sessions were 80–85% (S80), 90–95% (S90), and 98–102% (S100) of the STT velocity. Subsequent cycling and running were performed at a perceived maximal intensity. Swimming stroke mechanics were measured during the swim. Plasma lactate concentration and ratings of perceived exertion were recorded at the conclusion of the swim and over the course of subsequent cycling and running. Oxygen consumption was recorded during the cycle. Results: The S80 and S90 cycle times were faster than the S100 cycle time (p<0.05). The overall triathlon time of S80 was faster than that of S100 (p<0.05). The S100 swim was characterised by a greater stroke rate than S80 and S90 (p<0.05) and a greater plasma lactate concentration than S80 (p<0.01). Conclusion: A swimming intensity below that of a time trial effort significantly improves subsequent cycling and overall triathlon performance. PMID:16306507

  11. Dynamics of swimming bacteria at complex interfaces

    NASA Astrophysics Data System (ADS)

    Lopez, Diego; Lauga, Eric

    2014-07-01

    Flagellated bacteria exploiting helical propulsion are known to swim along circular trajectories near surfaces. Fluid dynamics predicts this circular motion to be clockwise (CW) above a rigid surface (when viewed from inside the fluid) and counter-clockwise (CCW) below a free surface. Recent experimental investigations showed that complex physicochemical processes at the nearby surface could lead to a change in the direction of rotation, both at solid surfaces absorbing slip-inducing polymers and interfaces covered with surfactants. Motivated by these results, we use a far-field hydrodynamic model to predict the kinematics of swimming near three types of interfaces: clean fluid-fluid interface, slipping rigid wall, and a fluid interface covered by incompressible surfactants. Representing the helical swimmer by a superposition of hydrodynamic singularities, we first show that in all cases the surfaces reorient the swimmer parallel to the surface and attract it, both of which are a consequence of the Stokes dipole component of the swimmer flow field. We then show that circular motion is induced by a higher-order singularity, namely, a rotlet dipole, and that its rotation direction (CW vs. CCW) is strongly affected by the boundary conditions at the interface and the bacteria shape. Our results suggest thus that the hydrodynamics of complex interfaces provide a mechanism to selectively stir bacteria.

  12. A molecular mechanism of optic nerve regeneration in fish: the retinoid signaling pathway.

    PubMed

    Kato, Satoru; Matsukawa, Toru; Koriyama, Yoshiki; Sugitani, Kayo; Ogai, Kazuhiro

    2013-11-01

    The fish optic nerve regeneration process takes more than 100 days after axotomy and comprises four stages: neurite sprouting (1-4 days), axonal elongation (5-30 days), synaptic refinement (35-80 days) and functional recovery (100-120 days). We screened genes specifically upregulated in each stage from axotomized fish retina. The mRNAs for heat shock protein 70 and insulin-like growth factor-1 rapidly increased in the retinal ganglion cells soon after axotomy and function as cell-survival factors. Purpurin mRNA rapidly and transiently increased in the photoreceptors and purpurin protein diffusely increased in all nuclear layers at 1-4 days after injury. The purpurin gene has an active retinol-binding site and a signal peptide. Purpurin with retinol functions as a sprouting factor for thin neurites. This neurite-sprouting effect was closely mimicked by retinoic acid and blocked by its inhibitor. We propose that purpurin works as a retinol transporter to supply retinoic acid to damaged RGCs which in turn activates target genes. We also searched for genes involved in the second stage of regeneration. The mRNA of retinoid-signaling molecules increased in retinal ganglion cells at 7-14 days after injury and tissue transglutaminase and neuronal nitric oxide synthase mRNAs, RA-target genes, increased in retinal ganglion cells at 10-30 days after injury. They function as factors for the outgrowth of thick, long neurites. Here we present a retinoid-signaling hypothesis to explain molecular events during the early stages of optic nerve regeneration in fish. PMID:23994437

  13. Synthesizing mechanisms of density dependence in reef fishes: behavior, habitat configuration, and observational scale.

    PubMed

    White, J Wilson; Samhouri, Jameal F; Stier, Adrian C; Wormald, Clare L; Hamilton, Scott L; Sandin, Stuart A

    2010-07-01

    Coral and rocky reef fish populations are widely used as model systems for the experimental exploration of density-dependent vital rates, but patterns of density-dependent mortality in these systems are not yet fully understood. In particular, the paradigm for strong, directly density-dependent (DDD) postsettlement mortality stands in contrast to recent evidence for inversely density-dependent (IDD) mortality. We review the processes responsible for DDD and IDD per capita mortality in reef fishes, noting that the pattern observed depends on predator and prey behavior, the spatial configuration of the reef habitat, and the spatial and temporal scales of observation. Specifically, predators tend to produce DDD prey mortality at their characteristic spatial scale of foraging, but prey mortality is IDD at smaller spatial scales due to attack-abatement effects (e.g., risk dilution). As a result, DDD mortality may be more common than IDD mortality on patch reefs, which tend to constrain predator foraging to the same scale as prey aggregation, eliminating attack-abatement effects. Additionally, adjacent groups of prey on continuous reefs may share a subset of refuges, increasing per capita refuge availability and relaxing DDD mortality relative to prey on patch reefs, where the patch edge could prevent such refuge sharing. These hypotheses lead to a synthetic framework to predict expected mortality patterns for a variety of scenarios. For nonsocial, nonaggregating species and species that aggregate in order to take advantage of spatially clumped refuges, IDD mortality is possible but likely superseded by DDD refuge competition, especially on patch reefs. By contrast, for species that aggregate socially, mortality should be IDD at the scale of individual aggregations but DDD at larger scales. The results of nearly all prior reef fish studies fit within this framework, although additional work is needed to test many of the predicted outcomes. This synthesis reconciles some

  14. Condition, prolonged swimming performance and muscle metabolic capacities of cod Gadus morhua.

    PubMed

    Martínez, M; Guderley, H; Dutil, J-D; Winger, P D; He, P; Walsh, S J

    2003-02-01

    This study evaluated the link between swimming endurance and condition of Atlantic cod Gadus morhua that had been fed or starved during the 16 weeks preceding the tests, and assessed whether muscle metabolic capacities explain such links. The condition factor [(somatic mass x fork length(-3))x100] of starved cod was 0.54+/-0.1 whereas that of fed cod was 0.81+/-0.1. In white and red muscle, we measured four glycolytic enzymes: phosphofructokinase (PFK), pyruvate kinase (PK), creatine kinase (CK) and lactate dehydrogenase (LDH), two mitochondrial enzymes: cytochrome c oxidase (CCO) and citrate synthase (CS), a biosynthetic enzyme, nucleoside diphosphate kinase (NDPK), glycogen and protein levels and water content. Muscle samples were taken at three positions along the length of the fish; starvation affected the metabolic capacities of white muscle more than those of red muscle. The levels of glycolytic enzymes and glycogen changed more in white than red muscle during starvation. Both in fed and starved cod, muscle metabolic capacities varied with position along the fish; starvation reduced this longitudinal variation more in white than red muscle. In white muscle of fed cod, the glycolytic enzyme levels increased from head to tail, while in starved cod this longitudinal variation disappeared. In red muscle mitochondrial enzyme levels were highest in the caudal sample, but fewer differences were found for glycolytic enzymes. Swimming endurance was markedly affected by fish condition, with starved fish swimming only 30% of the time (and distance) of fed fish. This endurance was closely linked with the number of burst-coast movements during the test and the activity of CCO and LDH in white muscle. The number of burst-coast movements was significantly linked with condition factor and PFK activity in caudal red muscle and gill arch mass. Our data indicated that cod use both glycolytic and oxidative capacities to support endurance swimming. Furthermore, swimming endurance

  15. The Effects of Limb Coordination on the Swimming Efficiency of Crayfish

    NASA Astrophysics Data System (ADS)

    Guy, Robert; Zhang, Jiawei; Zhang, Qinghai; Lewis, Timothy

    2012-11-01

    Limbs of crayfish, called swimmerets, move rhythmically in a metachronal wave that progresses from back to front during forward swimming. Neighboring swimmerets maintain phase-lags of about 25% over a wide range of frequencies. This ``phase constancy'' suggests that there may be mechanical advantages to this stroke pattern. We use the immersed-boundary method to simulate the coupled mechanics of the swimmerets and the surrounding fluid in order to explore how stroke patterns affect swimming efficiency.

  16. Masked auditory thresholds in sciaenid fishes: A comparative study

    NASA Astrophysics Data System (ADS)

    Ramcharitar, John; Popper, Arthur N.

    2004-09-01

    Western Atlantic sciaenids comprise a taxonomically diverse teleost family with significant variations in the relationship between the swim bladder and the otic capsule. In this study, the auditory brainstem response (ABR) was used to test the hypothesis that fishes with different peripheral auditory structures (black drum, Pogonias chromis and Atlantic croaker, Micropogonias undulatus) show differences in frequency selectivity. In a black drum the swim bladder is relatively distant from the otic capsule while the swim bladder in Atlantic croaker possesses anteriorly-directed diverticulas that terminate relatively near the otic capsule. Signals were pure tones in the frequency range, 100 Hz to 1.5 kHz, and thresholds were determined both with and without the presence of simultaneous white noise at two intensity levels (124 dB and 136 dB, re: 1 μPa). At the 124 dB level of white noise background, both the black drum and Atlantic croaker showed similar changes in auditory sensitivity. However, in the presence of the 136 dB white noise masker, black drum showed significantly greater shifts in auditory thresholds between 300 and 600 Hz. The results indicate that the two species differ in frequency selectivity since the Atlantic croaker was less susceptible to auditory threshold shifts, particularly at the higher level of masking. This difference may be linked to peripheral auditory mechanisms.

  17. Effect of hypergravity on carboanhydrase reactivity in inner ear ionocytes of developing cichlid fish.

    PubMed

    Beier, M; Anken, R H; Rahmann, H

    2004-01-01

    It has been shown earlier that hypergravity slows down inner ear otolith growth in developing fish. Otolith growth in terms of mineralization mainly depends on the enzyme carboanhydrase (CA), which is responsible for the provision of the pH-value necessary for calcium carbonate deposition. Larval siblings of cichlid fish (Oreochromis mossambicus) were subjected to hypergravity (3 g, hg; 6 h) during development and separated into normally and kinetotically swimming individuals following the transfer to 1 g (i.e., stopping the centrifuge; kinetotically behaving fish performed spinning movements). Subsequently, CA was histochemically demonstrated in inner ear ionocytes (cells involved in the endolymphatic ion exchange) and enzyme reactivity was determined densitometrically. It was found that both the total macular CA-reactivity as well as the difference in reactivities between the left and the right maculae (asymmetry) were significantly lower (1) in experimental animals as compared to the 1 g controls and (2) in normally swimming hg-animals as compared to the kinetotically behaving hg-fish. The results are in complete agreement with earlier studies, according to which hypergravity induces a decrease of otolith growth and the otolithic calcium incorporation (visualized using the calcium-tracer alizarin complexone) of kinetotically swimming hg-fish was higher as compared to normally behaving hyper-g animals. The present study thus strongly supports the concept that a regulatory mechanism, which adjusts otolith size and asymmetry as well as otolithic calcium carbonate incorporation towards the gravity vector, acts via activation/deactivation of macular CA. PMID:15803633

  18. Energetics of swimming by the platypus Ornithorhynchus anatinus: metabolic effort associated with rowing.

    PubMed

    Fish, F E; Baudinette, R V; Frappell, P B; Sarre, M P

    1997-10-01

    The metabolism of swimming in the platypus Ornithorhynchus anatinus Shaw was studied by measurement of oxygen consumption in a recirculating water flume. Platypuses swam against a constant water current of 0.45-1.0 ms-1. Animals used a rowing stroke and alternated bouts of surface and submerged swimming. Metabolic rate remained constant over the range of swimming speeds tested. The cost of transport decreased with increasing velocity to a minimum of 0.51 at 1.0 ms-1. Metabolic rate and cost of transport for the platypus were lower than values for semiaquatic mammals that swim at the water surface using a paddling mode. However, relative to transport costs for fish, the platypus utilized energy at a similar level to highly derived aquatic mammals that use submerged swimming modes. The efficient aquatic locomotion of the platypus results from its specialised rowing mode in conjunction with enlarged and flexible forefeet for high thrust generation and a behavioral strategy that reduces drag and energy cost by submerged swimming. PMID:9359371

  19. Interaction of two swimming Paramecia.

    PubMed

    Ishikawa, Takuji; Hota, Masateru

    2006-11-01

    The interaction between two swimming Paramecium caudatum was investigated experimentally. Cell motion was restricted between flat plates, and avoiding and escape reactions were observed, as well as hydrodynamic interactions. The results showed that changes in direction between two swimming cells were induced mainly by hydrodynamic forces and that the biological reaction was a minor factor. Numerical simulations were also performed using a boundary element method. P. caudatum was modelled as a rigid spheroid with surface tangential velocity measured by a particle image velocimetry (PIV) technique. Hydrodynamic interactions observed in the experiment agreed well with the numerical simulations, so we can conclude that the present cell model is appropriate for describing the motion of P. caudatum. PMID:17079716

  20. Unsteady swimming of small organisms

    NASA Astrophysics Data System (ADS)

    Wang, Shiyan; Ardekani, Arezoo

    2012-11-01

    Small planktonic organisms ubiquitously display unsteady or impulsive motion to attack a prey or escape a predator in natural environments. Despite this, the role of unsteady hydrodynamic forces such as history and added mass forces on the low Reynolds number propulsion of small organisms is poorly understood. In this paper, we derive the fundamental equation of motion for an organism swimming by the means of surface distortion in a nonuniform flow at a low Reynolds number regime. We show that the history and added mass forces, that where traditionally neglected in the literature for small swimming organisms, cannot be neglected as the Stokes number increases above unity. For example, these unsteady inertial forces are of the same order as quasi-steady Stokes forces for Paramecium. Finally, we quantify the effects of convective inertial forces in the limit of small, but nonzero, Reynolds number regime. This work is supported by NSF grant CBET-1066545.

  1. Swimming bacteria at complex interfaces

    NASA Astrophysics Data System (ADS)

    Lopez, Diego; Lauga, Eric

    2013-11-01

    Swimming microorganisms such as bacteria often move in confined geometries. Such confinement can be caused by the presence of solid boundaries, free surfaces, or liquid interfaces. It is well established that confinement affects significantly locomotion, generating additional forces and torques on the bacteria. In the presence of a solid boundary (imposing a no-slip condition), microorganisms using helical propulsion undergo circular motion (clockwise in the case of E. coli). Conversely, close to a free (no-shear) surface the circular motion is reversed. However, realistic interfaces are complex, and experimental results do not always agree with theoretical predictions. In this work, we show, using analytical modeling, how different complex interfaces affect a nearby bacterium and modify its swimming kinematics. IUSTI UMR 7343, Polytech Marseille, France.

  2. Team swimming in ant spermatozoa

    PubMed Central

    Pearcy, Morgan; Delescaille, Noémie; Lybaert, Pascale; Aron, Serge

    2014-01-01

    In species where females mate promiscuously, competition between ejaculates from different males to fertilize the ova is an important selective force shaping many aspects of male reproductive traits, such as sperm number, sperm length and sperm–sperm interactions. In eusocial Hymenoptera (bees, wasps and ants), males die shortly after mating and their reproductive success is ultimately limited by the amount of sperm stored in the queen's spermatheca. Multiple mating by queens is expected to impose intense selective pressure on males to optimize the transfer of sperm to the storage organ. Here, we report a remarkable case of cooperation between spermatozoa in the desert ant Cataglyphis savignyi. Males ejaculate bundles of 50–100 spermatozoa. Sperm bundles swim on average 51% faster than solitary sperm cells. Team swimming is expected to increase the amount of sperm stored in the queen spermatheca and, ultimately, enhance male posthumous fitness. PMID:24919705

  3. Numerical simulations of flying and swimming of biological systems with the viscous vortex particle method

    NASA Astrophysics Data System (ADS)

    Eldredge, Jeff

    2005-11-01

    Many biological mechanisms of locomotion involve the interaction of a fluid with a deformable surface undergoing large unsteady motion. Analysis of such problems poses a significant challenge to conventional grid-based computational approaches. Particularly in the moderate Reynolds number regime where many insects and fish function, viscous and inertial processes are both important, and vorticity serves a crucial role. In this work, the viscous vortex particle method is shown to provide an efficient, intuitive simulation approach for investigation of these biological systems. In contrast with a grid-based approach, the method solves the Navier--Stokes equations by tracking computational particles that carry smooth blobs of vorticity and exchange strength with one another to account for viscous diffusion. Thus, computational resources are focused on the physically relevant features of the flow, and there is no need for artificial boundary conditions. Building from previously-developed techniques for the creation of vorticity to enforce no-throughflow and no-slip conditions, the present method is extended to problems of coupled fluid--body dynamics by enforcement of global conservation of momenta. The application to several two-dimensional model problems is demonstrated, including single and multiple flapping wings and free swimming of a three-linkage fish.

  4. Convergence in Underwater Swimming Between Nature and Engineering

    NASA Astrophysics Data System (ADS)

    Bandyopadhyay, Promode R.; Boller, Michael

    2004-11-01

    We are interested in comparing the hydrodynamic performance of underwater vehicles and swimming animals which are believed to have been optimized via evolution. Cruising and maneuvering are treated separately. Platforms like submarines are primarily cruising vehicles, while torpedoes are dexterous in both. In swimming animals, generally, red muscle is used for cruising while white muscle is used for maneuvering motions. Data from literature is examined comparing shaft/muscle power versus displacement. Experiments also have been carried out with captive mackerel and bluefish that are known to be open water fish and are proficient in both cruising and maneuvering. Their trajectories around obstacles have been recorded and analyzed. Similar figure of eight' maneuvering trajectory data of engineering underwater vehicles have also been analyzed. It is shown that there is convergence between nature and engineering in cruising that extend over eight decades of variation in power and displacement. However, swimming animals are still more proficient in maneuvering, although the gap has been closing of late.

  5. Nutritional recommendations for synchronized swimming.

    PubMed

    Robertson, Sherry; Benardot, Dan; Mountjoy, Margo

    2014-08-01

    The sport of synchronized swimming is unique, because it combines speed, power, and endurance with precise synchronized movements and high-risk acrobatic maneuvers. Athletes must train and compete while spending a great amount of time underwater, upside down, and without the luxury of easily available oxygen. This review assesses the scientific evidence with respect to the physiological demands, energy expenditure, and body composition in these athletes. The role of appropriate energy requirements and guidelines for carbohydrate, protein, fat, and micronutrients for elite synchronized swimmers are reviewed. Because of the aesthetic nature of the sport, which prioritizes leanness, the risks of energy and macronutrient deficiencies are of significant concern. Relative Energy Deficiency in Sport and disordered eating/eating disorders are also of concern for these female athletes. An approach to the healthy management of body composition in synchronized swimming is outlined. Synchronized swimmers should be encouraged to consume a well-balanced diet with sufficient energy to meet demands and to time the intake of carbohydrate, protein, and fat to optimize performance and body composition. Micronutrients of concern for this female athlete population include iron, calcium, and vitamin D. This article reviews the physiological demands of synchronized swimming and makes nutritional recommendations for recovery, training, and competition to help optimize athletic performance and to reduce risks for weight-related medical issues that are of particular concern for elite synchronized swimmers. PMID:24667278

  6. Finding the best swimming sheet

    NASA Astrophysics Data System (ADS)

    Ives, Tom; Morozov, Alexander

    2014-11-01

    Many microorganisms propel through fluid environments by undulating their bodies or long thin organelles (flagella). The particular waveform of the undulations can often be changed by the organism to adapt to particular environmental conditions. It has been proposed in the literature that this adaptation is driven by the desire to optimise the swimming efficiency. However, it remains an open question as to whether this is indeed the optimised quantity for microorganisms. We study propulsion in Newtonian fluids at zero inertia for a model organism, the so-called Taylor waving sheet. We develop a numerical method that allows us to calculate flow fields for sheets of arbitrary waverforms in the bulk and next to a wall. We perform optimisations of various quantities that can potentially be optimised by a swimming microorganisms (efficiency, speed, etc.) and present the optimal waveforms. We also present a simple analytical model that yields similar results. We conclude that various optimal waveforms are very similar, both in the bulk and next to a boundary, and one cannot claim that optimising the swimming efficiency is the strategy adopted by undulating microorganisms. SUPA, School of Physics & Astronomy, University of Edinburgh, UK.

  7. An updated protocol to assess arm swimming power in front crawl.

    PubMed

    Dominguez-Castells, R; Izquierdo, M; Arellano, R

    2013-04-01

    Mechanical power output is a reliable predictor of swim speed in front crawl. However, a complete power curve (power vs. load) has not been described for swimming, and intra-cycle power has not been assessed. The purpose of this study was to examine intra-cycle power output at propulsive phases and to determine maximum swimming power, the corresponding load and swimming speed. 18 swimmers (age 22.10±4.31years, height 1.79±0.07 m, arm span 1.85±0.08 m and body mass 76.74±9.00 kg) performed a swim power test. It consisted of 12.5 m all-out swims with only the arms, with a load attached to the swimmer. A linear encoder and a load cell recorded intra-cycle speed and force in each trial. The test was recorded with 2 underwater cameras. Intra-cycle power was obtained for propulsive stroke phases (pull: 60.32±18.87 W; push: 71.21±21.06 W). Peak power was 114.37±33.16 W. Mean maximum swim power was 66.49 W (0.86 W/kg), which was reached at a swimming velocity of 0.75 m/s with a 47.07% of the individual maximal load. Significant positive correlation (r=0.76, p<0.01) between maximum swim power and maximum swim speed was observed. These results suggest that the proposed test may be a training tool that is relatively simple to implement and would provide swimmers and coaches with quick feedback. PMID:23065661

  8. The role of 5-HT₁A receptors in fish oil-mediated increased BDNF expression in the rat hippocampus and cortex: a possible antidepressant mechanism.

    PubMed

    Vines, Aparecida; Delattre, Ana Marcia; Lima, Marcelo M S; Rodrigues, Laís Soares; Suchecki, Deborah; Machado, Ricardo B; Tufik, Sergio; Pereira, Sofia I R; Zanata, Sílvio M; Ferraz, Anete Curte

    2012-01-01

    Epidemiological and dietary studies show that nutritional deficit of omega-3 polyunsaturated fatty acids (ω-3 PUFA) is directly related to the prevalence and severity of depression. Supplementation with docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) during critical periods of development (pregnancy and lactation) is essential for cortical maturation, synaptogenesis and myelination, and may also mitigate the risk for cognitive deficits and psychopathologies in young adults. The present study was performed to evaluate the involvement of serotonin (5-HT) receptors, particularly of 5-HT(1A), and hippocampal brain-derived neurotrophic factor (BDNF) expression in the antidepressant effect of ω-3 PUFA supplementation. In Experiment 1, the antidepressant effects of fish oil were assessed by the modified forced swim test in adult rats. The data indicated a robust antidepressant effect produced by this supplementation and that treatment of the rats with WAY 100135 reversed this effect. In Experiment 2, cortical and hippocampal contents of BDNF, 5-HT, dopamine (DA) and its metabolites, 5-hydroxyindoleacetic acid (5-HIAA), and 3,4-dihydroxyphenylacetic acid (DOPAC), were determined in animals subjected to the same protocol. Increased BDNF expression in the cortex and hippocampus of both age groups was detected. In 90 day-old rats, 5-HT content in the hippocampus was increased, whereas 5-HIAA formation was diminished in the fish oil group. We suggest the occurrence of a reciprocal involvement of 5-HT(1A) receptors activation and the hippocampal BDNF-increased expression mediated by fish oil supplementation. These data corroborate and expand the notion that supplementation with ω-3 PUFA produces antidepressant effects mediated by an increase in serotonergic neurotransmission, particularly in the hippocampus. This article is part of a Special Issue entitled 'Anxiety and Depression'. PMID:21740919

  9. Three-Dimensional Analysis of the Swimming Behavior of Daphnia magna Exposed to Nanosized Titanium Dioxide

    PubMed Central

    Noss, Christian; Dabrunz, André; Rosenfeldt, Ricki R.; Lorke, Andreas; Schulz, Ralf

    2013-01-01

    Due to their surface characteristics, nanosized titanium dioxide particles (nTiO2) tend to adhere to biological surfaces and we thus hypothesize that they may alter the swimming performance and behavior of motile aquatic organisms. However, no suitable approaches to address these impairments in swimming behavior as a result of nanoparticle exposure are available. Water fleas Daphnia magna exposed to 5 and 20 mg/L nTiO2 (61 nm; polydispersity index: 0.157 in 17.46 mg/L stock suspension) for 96 h showed a significantly (p<0.05) reduced growth rate compared to a 1-mg/L treatment and the control. Using three-dimensional video observations of swimming trajectories, we observed a treatment-dependent swarming of D. magna in the center of the test vessels during the initial phase of the exposure period. Ensemble mean swimming velocities increased with increasing body length of D. magna, but were significantly reduced in comparison to the control in all treatments after 96 h of exposure. Spectral analysis of swimming velocities revealed that high-frequency variance, which we consider as a measure of swimming activity, was significantly reduced in the 5- and 20-mg/L treatments. The results highlight the potential of detailed swimming analysis of D. magna for the evaluation of sub-lethal mechanical stress mechanisms resulting from biological surface coating and thus for evaluating the effects of nanoparticles in the aquatic environment. PMID:24260519

  10. Molecular developmental mechanism in polypterid fish provides insight into the origin of vertebrate lungs.

    PubMed

    Tatsumi, Norifumi; Kobayashi, Ritsuko; Yano, Tohru; Noda, Masatsugu; Fujimura, Koji; Okada, Norihiro; Okabe, Masataka

    2016-01-01

    The lung is an important organ for air breathing in tetrapods and originated well before the terrestrialization of vertebrates. Therefore, to better understand lung evolution, we investigated lung development in the extant basal actinopterygian fish Senegal bichir (Polypterus senegalus). First, we histologically confirmed that lung development in this species is very similar to that of tetrapods. We also found that the mesenchymal expression patterns of three genes that are known to play important roles in early lung development in tetrapods (Fgf10, Tbx4, and Tbx5) were quite similar to those of tetrapods. Moreover, we found a Tbx4 core lung mesenchyme-specific enhancer (C-LME) in the genomes of bichir and coelacanth (Latimeria chalumnae) and experimentally confirmed that these were functional in tetrapods. These findings provide the first molecular evidence that the developmental program for lung was already established in the common ancestor of actinopterygians and sarcopterygians. PMID:27466206

  11. Molecular developmental mechanism in polypterid fish provides insight into the origin of vertebrate lungs

    PubMed Central

    Tatsumi, Norifumi; Kobayashi, Ritsuko; Yano, Tohru; Noda, Masatsugu; Fujimura, Koji; Okada, Norihiro; Okabe, Masataka

    2016-01-01

    The lung is an important organ for air breathing in tetrapods and originated well before the terrestrialization of vertebrates. Therefore, to better understand lung evolution, we investigated lung development in the extant basal actinopterygian fish Senegal bichir (Polypterus senegalus). First, we histologically confirmed that lung development in this species is very similar to that of tetrapods. We also found that the mesenchymal expression patterns of three genes that are known to play important roles in early lung development in tetrapods (Fgf10, Tbx4, and Tbx5) were quite similar to those of tetrapods. Moreover, we found a Tbx4 core lung mesenchyme-specific enhancer (C-LME) in the genomes of bichir and coelacanth (Latimeria chalumnae) and experimentally confirmed that these were functional in tetrapods. These findings provide the first molecular evidence that the developmental program for lung was already established in the common ancestor of actinopterygians and sarcopterygians. PMID:27466206

  12. On the efficient swimming of a ray-inspired underwater vehicle Part I: Experimental study on swimming optimization of control and fin structure

    NASA Astrophysics Data System (ADS)

    Zhu, Jianzhong; Lopez, Mervyn; Williams, Ventress; Aluko, Theophilus; Dong, Haibo; Bart-Smith, Hilary

    2014-11-01

    Batoid fish such as manta and cownose rays are among the most agile and energy efficient swimming creatures. These capabilities arise from flapping and bending their dorsally flattened pectoral fins. To assess this contribution, this study focuses on the study of a bio-inspired underwater vehicle--the MantaBot--where biological design criteria are applied. The MantaBot consists of two parts: a rigid body rendered from a CT scanning image of a cownose ray and two flexible fins driven by tensegrity actuators. The experiments were conducted in a water tank where the MantaBot was attached to a rail for rectilinear swimming. Three stereo-videos were taken and digitized to measure the 3D kinematics. Results showed that the fins conduct deformations in both spanwise and chordwise directions during steady swimming. Optimal operation conditions were determined for fastest swimming by surveying a wide range of parameters. Contributions of thrust generation and amplitude hindrance of various portions of the fin volume were examined. Additionally, fin tip structure, material and bending properties were studied for optimal swimming. This research was supported by the Office of Naval Research (ONR) under the Multidisciplinary University Research Initiative (MURI) Grant N00014-08-1-0642 and Grant N00014-14-1-0533.

  13. Swimming behaviour of the upside-down swimming catfish ( Synodontis nigriventris) at high-quality microgravity - A drop-tower experiment

    NASA Astrophysics Data System (ADS)

    Anken, R.; Hilbig, R.

    2009-07-01

    The catfish Synodontis nigriventris often shows a unique swimming behaviour in being oriented upside-down. When swimming near a (e.g., vertical) substrate, however, the animals orient themselves with their ventral side towards this substrate. This tendency is called ventral substrate response (VSR). The VSR does not only override the upside-down swimming behaviour but also the dorsal light response and the ventral light response. In the course of an earlier drop-tower experiment performed at ZARM (Bremen, Germany) using cichlid fish ( Oreochromis mossambicus), we had observed that about 90% of the animals revealed sensorimotor disorders (kinetotic swimming) due to the almost complete lack of gravity as a cue for orientation. In order to further assess the importance of the VSR for postural control in S. nigriventris when being located near a substrate, we subjected catfish in relatively small chambers to drop-tower flights. In contrast to our results regarding cichlid fish, S. nigriventris showed no kinetotic behaviour. This clearly suggests that the VSR overrides even vestibular input and possibly represents the most important single behavioural response in this species.

  14. Targeted delivery of colloids by swimming bacteria

    PubMed Central

    Koumakis, N.; Lepore, A.; Maggi, C.; Di Leonardo, R.

    2013-01-01

    The possibility of exploiting motile microorganisms as tiny propellers represents a fascinating strategy for the transport of colloidal cargoes. However, delivery on target sites usually requires external control fields to steer propellers and trigger cargo release. The need for a constant feedback mechanism prevents the design of compact devices where biopropellers could perform their tasks autonomously. Here we show that properly designed three-dimensional (3D) microstructures can define accumulation areas where bacteria spontaneously and efficiently store colloidal beads. The process is stochastic in nature and results from the rectifying action of an asymmetric energy landscape over the fluctuating forces arising from collisions with swimming bacteria. As a result, the concentration of colloids over target areas can be strongly increased or depleted according to the topography of the underlying structures. Besides the significance to technological applications, our experiments pose some important questions regarding the structure of stationary probability distributions in non-equilibrium systems. PMID:24100868

  15. A RAD-Tag Genetic Map for the Platyfish (Xiphophorus maculatus) Reveals Mechanisms of Karyotype Evolution Among Teleost Fish

    PubMed Central

    Amores, Angel; Catchen, Julian; Nanda, Indrajit; Warren, Wesley; Walter, Ron; Schartl, Manfred; Postlethwait, John H.

    2014-01-01

    Mammalian genomes can vary substantially in haploid chromosome number even within a small taxon (e.g., 3–40 among deer alone); in contrast, teleost fish genomes are stable (24–25 in 58% of teleosts), but we do not yet understand the mechanisms that account for differences in karyotype stability. Among perciform teleosts, platyfish (Xiphophorus maculatus) and medaka (Oryzias latipes) both have 24 chromosome pairs, but threespine stickleback (Gasterosteus aculeatus) and green pufferfish (Tetraodon nigroviridis) have just 21 pairs. To understand the evolution of teleost genomes, we made a platyfish meiotic map containing 16,114 mapped markers scored on 267 backcross fish. We tiled genomic contigs along the map to create chromosome-length genome assemblies. Genome-wide comparisons of conserved synteny showed that platyfish and medaka karyotypes remained remarkably similar with few interchromosomal translocations but with numerous intrachromosomal rearrangements (transpositions and inversions) since their lineages diverged ∼120 million years ago. Comparative genomics with platyfish shows how reduced chromosome numbers in stickleback and green pufferfish arose by fusion of pairs of ancestral chromosomes after their lineages diverged from platyfish ∼195 million years ago. Zebrafish and human genomes provide outgroups to root observed changes. These studies identify likely genome assembly errors, characterize chromosome fusion events, distinguish lineage-independent chromosome fusions, show that the teleost genome duplication does not appear to have accelerated the rate of translocations, and reveal the stability of syntenies and gene orders in teleost chromosomes over hundreds of millions of years. PMID:24700104

  16. Is pigment patterning in fish skin determined by the Turing mechanism?

    PubMed

    Watanabe, Masakatsu; Kondo, Shigeru

    2015-02-01

    More than half a century ago, Alan Turing postulated that pigment patterns may arise from a mechanism that could be mathematically modeled based on the diffusion of two substances that interact with each other. Over the past 15 years, the molecular and genetic tools to verify this prediction have become available. Here, we review experimental studies aimed at identifying the mechanism underlying pigment pattern formation in zebrafish. Extensive molecular genetic studies in this model organism have revealed the interactions between the pigment cells that are responsible for the patterns. The mechanism discovered is substantially different from that predicted by the mathematical model, but it retains the property of 'local activation and long-range inhibition', a necessary condition for Turing pattern formation. Although some of the molecular details of pattern formation remain to be elucidated, current evidence confirms that the underlying mechanism is mathematically equivalent to the Turing mechanism. PMID:25544713

  17. Degradation Products of Benzophenone-3 in Chlorinated Seawater Swimming Pools.

    PubMed

    Manasfi, Tarek; Storck, Veronika; Ravier, Sylvain; Demelas, Carine; Coulomb, Bruno; Boudenne, Jean-Luc

    2015-08-01

    Oxybenzone (2-hydroxy-4-methoxyphenone, benzophenone-3) is one of the UV filters commonly found in sunscreens. Its presence in swimming pools and its reactivity with chlorine has already been demonstrated but never in seawater swimming pools. In these pools, chlorine added for disinfection results in the formation of bromine, due to the high levels of bromide in seawater, and leads to the formation of brominated disinfection byproducts, known to be more toxic than chlorinated ones. Therefore, it seems important to determine the transformation products of oxybenzone in chlorinated seawater swimming pools; especially that users of seawater swimming pools may apply sunscreens and other personal-care products containing oxybenzone before going to pools. This leads to the introduction of oxybenzone to pools, where it reacts with bromine. For this purpose, the reactivity of oxybenzone has been examined as a function of chlorine dose and temperature in artificial seawater to assess its potential to produce trihalomethanes and to determine the byproducts generated following chlorination. Increasing doses of chlorine and increasing temperatures enhanced the formation of bromoform. Experiments carried out with excess doses of chlorine resulted in the degradation of oxybenzone and allowed the determination of the degradation mechanisms leading to the formation of bromoform. In total, ten transformation products were identified, based on which the transformation pathway was proposed. PMID:26167727

  18. Numerical and experimental investigations of human swimming motions

    PubMed Central

    Takagi, Hideki; Nakashima, Motomu; Sato, Yohei; Matsuuchi, Kazuo; Sanders, Ross H.

    2016-01-01

    ABSTRACT This paper reviews unsteady flow conditions in human swimming and identifies the limitations and future potential of the current methods of analysing unsteady flow. The capability of computational fluid dynamics (CFD) has been extended from approaches assuming steady-state conditions to consideration of unsteady/transient conditions associated with the body motion of a swimmer. However, to predict hydrodynamic forces and the swimmer’s potential speeds accurately, more robust and efficient numerical methods are necessary, coupled with validation procedures, requiring detailed experimental data reflecting local flow. Experimental data obtained by particle image velocimetry (PIV) in this area are limited, because at present observations are restricted to a two-dimensional 1.0 m2 area, though this could be improved if the output range of the associated laser sheet increased. Simulations of human swimming are expected to improve competitive swimming, and our review has identified two important advances relating to understanding the flow conditions affecting performance in front crawl swimming: one is a mechanism for generating unsteady fluid forces, and the other is a theory relating to increased speed and efficiency. PMID:26699925

  19. Sea Butterfly Swimming: Time-resolved Tomographic PIV measurements

    NASA Astrophysics Data System (ADS)

    Murphy, David; Zheng, Lingxiao; Mittal, Rajat; Webster, Donald; Yen, Jeannette

    2011-11-01

    The planktonic sea butterfly Limacina helicina swims by flapping its flexible, wing-like parapodia. The appendage stroke kinematics of this shell-bearing pteropod are three-dimensional and likely contain elements of both drag-based (rowing) and lift-based (flapping) propulsion. Unsteady lift-generating mechanisms such as clap-and-fling may also be present. Upstroke and downstroke motions both propel the animal upward and roll it forwards and backwards, resulting in a sawtooth trajectory. We present time-resolved, tomographic PIV measurements of flow generated by free-swimming pteropods (Limacina helicina) moving upwards with average swimming speeds of 5 - 17 mm/s. The pteropods beat their appendages with a stroke frequency of 4 - 5 Hz. With a size range of 1 - 2 mm, the animals filmed in this study operate in a viscous environment with a Reynolds number of 5 to 20. The volumetric flow measurements provide insight into the three dimensional nature of the flow and into the relative importance of drag- and lift-based propulsion at this low Reynolds number. Preliminary results from Navier-Stokes simulations of the flow associated with the swimming of this organism will also be presented.

  20. Numerical and experimental investigations of human swimming motions.

    PubMed

    Takagi, Hideki; Nakashima, Motomu; Sato, Yohei; Matsuuchi, Kazuo; Sanders, Ross H

    2016-08-01

    This paper reviews unsteady flow conditions in human swimming and identifies the limitations and future potential of the current methods of analysing unsteady flow. The capability of computational fluid dynamics (CFD) has been extended from approaches assuming steady-state conditions to consideration of unsteady/transient conditions associated with the body motion of a swimmer. However, to predict hydrodynamic forces and the swimmer's potential speeds accurately, more robust and efficient numerical methods are necessary, coupled with validation procedures, requiring detailed experimental data reflecting local flow. Experimental data obtained by particle image velocimetry (PIV) in this area are limited, because at present observations are restricted to a two-dimensional 1.0 m(2) area, though this could be improved if the output range of the associated laser sheet increased. Simulations of human swimming are expected to improve competitive swimming, and our review has identified two important advances relating to understanding the flow conditions affecting performance in front crawl swimming: one is a mechanism for generating unsteady fluid forces, and the other is a theory relating to increased speed and efficiency. PMID:26699925

  1. Strain Variants in Swimming Characteristics of a Predatory Algae Species

    NASA Astrophysics Data System (ADS)

    Sheng, Jian; Katz, Joseph; Adolf, J.; Place, Allen

    2009-11-01

    Digital holographic microscopic cinematography is used for measuring the 3D, time resolved, swimming behavior of toxic and non-toxic strains of the marine dinoflagellates Karlodinium veneficum. The experiments are performed in a 3x3 mm square cuvette at densities of ˜150,000 cells/ml, and holograms are recorded at 120fps and 20X magnification for 12-20s. In each case, we simultaneously track 200-500 cells in the 3mm deep sample, at a spatial resolution of 0.4x0.4x2 μm. Results show that all strains prefer vertical migration during phototrophic growth and localized foraging in response to prey. Strains capable of swimming in both left and right hand helices show stronger tendency towards vertical motion than right handed strains. Swimming-induced dispersion computed from Lagrangian trajectories corroborates the observed migration trends, and suggests a mechanism for predation-induced cell aggregation into dense bloom. Velocity spectra and conditional sampling of swimming modes will also be presented to elucidate locomotion of dinoflagellates.

  2. Brain glycogen supercompensation after different conditions of induced hypoglycemia and sustained swimming in rainbow trout (Oncorhynchus mykiss).

    PubMed

    Blanco, A M; Gómez-Boronat, M; Pérez-Maceira, J; Mancebo, M J; Aldegunde, M

    2015-09-01

    Brain glycogen is depleted when used as an emergency energy substrate. In mammals, brain glycogen levels rebound to higher than normal levels after a hypoglycemic episode and a few hours after refeeding or administration of glucose. This phenomenon is called glycogen supercompensation. However, this mechanism has not been investigated in lower vertebrates. The aim of this study was therefore to determine whether brain glycogen supercompensation occurs in the rainbow trout brain. For this purpose, short-term brain glucose and glycogen contents were determined in rainbow trout after being subjected to the following experimental conditions: i) a 5-day or 10-day fasting period and refeeding; ii) a single injection of insulin (4 mg kg(-1)) and refeeding; and iii) sustained swimming and injection of glucose (500 mg kg(-1)). Food deprivation during the fasting periods and insulin administration both induced a decrease in glucose and glycogen levels in the brain. However, only refeeding after 10 days of fasting significantly increased the brain glycogen content above control levels, in a clear short-term supercompensation response. Unlike in mammals, prolonged exercise did not alter brain glucose or glycogen levels. Furthermore, brain glycogen supercompensation was not observed after glucose administration in fish undergoing sustained swimming. To our knowledge, this is the first study providing direct experimental evidence for the existence of a short-term glycogen supercompensation response in a teleost brain, although the response was only detectable after prolonged fasting. PMID:25956213

  3. Response acquisition by Siamese fighting fish (Betta splendens) with delayed visual reinforcement.

    PubMed

    Lattal, K A; Metzger, B

    1994-01-01

    Male Siamese fighting fish, Betta splendens, swam through a ring in an aquarium, breaking a photocell beam and initiating an unsignaled, resetting delay interval. Following delays of 0 s, 10 s, or 25 s, a 15-s mirror presentation released an aggressive display by the fish. Swimming through the ring increased in the absence of either a period of acclimatization to the reinforcer (analogous to magazine training when appetitive reinforcers are used) or explicit training of the response by the experimenters. Response rates were a decreasing function of delay duration. Other fish exposed to a schedule of response-independent mirror presentations failed to acquire and maintain the response. The results demonstrate the robustness and generality of the phenomenon of response acquisition with delayed reinforcement. They further qualify earlier observations about behavioral mechanisms involved in the phenomenon. PMID:16812724

  4. Swimming-Induced Taste Aversion and Its Prevention by a Prior History of Swimming

    ERIC Educational Resources Information Center

    Masaki, Takahisa; Nakajima, Sadahiko

    2004-01-01

    In two experiments, the evidence showed that 20 min of forced swimming by rats caused aversion to a taste solution consumed before swimming. When one of two taste solutions (sodium saccharin or sodium chloride, counterbalanced across rats) was paired with swimming and the other was not, the rats' intakes of these two solutions showed less…

  5. Model identification and controller design of a fish-like robot

    NASA Astrophysics Data System (ADS)

    Ariyanto, Irfan; Kang, Taesam; Chan, Wai Leung; Lee, Youngjae

    2007-04-01

    Robotic fish is an interesting and prospective subject to develop. The simplest fish swimming mode to be mimicked for fish robots is the ostraciiform mode which only requires caudal fin flapping. An almost submerged ostraciiform fish robot was constructed to study its swimming characteristics. The swimming direction can be controlled by changing the mean angle of caudal fin oscillation. Experiments were conducted to study the behavior of the fish robot and in particular, the transfer function between swimming path angular rate and mean angle of the caudal fin oscillation were identified. Error to signal ratio quantity was used to determine how well the model fits with the experimental data. This identification model was used to design a 2-degree-of-freedom PID controller that meets some specific requirements to improve the steering performance.

  6. Numerical Model for Fish-Like Locomotion in Potential Flow

    NASA Astrophysics Data System (ADS)

    Melli-Huber, Juan; Rowley, Clarence; Rufat, Dzhelil; Kanso, Eva; Marsden, Jerrold

    2004-11-01

    An accurate yet tractable model of fish-like locomotion is essential for the design and control of underwater vehicles with advanced swimming capabilities and improved efficiency. Our emphasis is on developing a model that predicts forces and moments accurately, yet is simple enough to apply mathematical tools for analyzing robotic locomotion. We focus on modeling thunniform-type swimming in which a high-aspect ratio tail moves relative to a fairly rigid body. The fish is modeled as a discrete number of rigid bodies, which may represent the body, peduncle and tail. We have developed a numerical model to simulate the motion of rigid bodies in an inviscid, incompressible two-dimensional potential flow with no pre-existing vorticity. Although the flow is inviscid and there is no vorticity or mechanism for generating vorticity, the motion of the bodies will be coupled due to their added inertia terms. Unlike previous models, this work is not restricted to small amplitude motions, does not assume that the bodies are hydrodynamically decoupled and allows for arbitrary body geometry. We present gaits to achieve steering and forward motion and compare the result to a hydrodynamically decoupled model.

  7. Feeding of swimming Paramecium with fore-aft asymmetry in viscous fluid

    NASA Astrophysics Data System (ADS)

    Zhang, Peng; Jana, Saikat; Giarra, Matthew; Vlachos, Pavlos; Jung, Sunghwan

    2013-11-01

    Swimming behaviours and feeding efficiencies of Paramecium Multimicronucleatum with fore-aft asymmetric body shapes are studied experimentally and numerically. Among various possible swimming ways, ciliates typically exhibit only one preferred swimming directions in favorable conditions. Ciliates, like Paramecia, with fore-aft asymmetric shapes preferably swim towards the slender anterior while feeding fluid to the oral groove located at the center of the body. Since both feeding and swimming efficiencies are influenced by fluid motions around the body, it is important to reveal the fluid mechanics around a moving object. Experimentally, μ-PIV methods are employed to characterize the source-dipole streamline patterns and fluid motions around Paramecium. Numerical simulations by boundary element methods are also used to evaluate surface stresses and velocities, which give insights into the efficiencies of swimming and feeding depending on body asymmetry. It is concluded that a slender anterior and fat posterior increases the combined efficiency of swimming and feeding, which matches well with actual shapes of Paramecium. Discrepancies between experiments and simulations are also discussed.

  8. Respiration and circulation during swimming activity in the dogfish Scyliorhinus stellaris.

    PubMed

    Piiper, J; Meyer, M; Worth, H; Willmer, H

    1977-06-01

    A number of respiratory and circulatory parameters was measured in the Larger Spotted Dogfish Scyliorhinus stellaris before, during and after periods of spontaneous swimming. During swimming the gill ventilation was increased, mainly due to increased ventilatory stroke volume, the respiratory frequency showing a small rise only, and the cardiac output was increased at only slightly elevated cardiac frequency. Coordination between cardiac, ventilatory or locomotor (tail-beat) rhythms was not observed. The decrease in utilization of inspired water O2 during swimming was attributable to diffusion limitation in branchial O2 transfer. A considerable fraction of the total net amount of O2 required for swimming was taken up during the recovery phase. From the observations that (1) the decrease in gill ventilatory flow after cessation of swimming revealed a very rapid component (followed by a slow component), and that (2) changes in swimming speed were reflected by immediate changes in momentary ventilatory flow, it is concluded that the increased ventilation during swimming was in part mechanical-passive and/or due to nervous coupling between respiratory and locomotor centers. PMID:877447

  9. Unilateral ablation of trunk superficial neuromasts increases directional instability during steady swimming in the yellowtail kingfish Seriola lalandi.

    PubMed

    Yanase, K; Herbert, N A; Montgomery, J C

    2014-09-01

    Detailed swimming kinematics of the yellowtail kingfish Seriola lalandi were investigated after unilateral ablation of superficial neuromasts (SNs). Most kinematic variables, such as tail-beat frequency, stride length, caudal fin-beat amplitude and propulsive wavelength, were unaffected but lateral amplitude at the tip of the snout (A0 ) was significantly increased in SN-disrupted fish compared with sham-operated controls. In addition, the orientation of caudal fin-tip relative to the overall swimming direction of SN-disrupted fish was significantly deflected (two-fold) in comparison with sham-operated control fish. In some fish, SN disruption also led to a phase distortion of the propulsive body-wave. These changes would be expected to increase both hydrodynamic drag and thrust production which is consistent with the finding that SN-disrupted fish had to generate significantly greater thrust power when swimming at ≥1·3 fork lengths (LF ) s(-1) . In particular, hydrodynamic drag would increase as a result of any increase in rotational (yaw) perturbation and sideways slip resulting from the sensory disturbance. In conclusion, unilateral SN ablation produced directional instability of steady swimming and altered propulsive movements, suggesting a role for sensory feedback in correcting yaw and slip disturbances to maintain efficient locomotion. PMID:25082013

  10. Physiological responses of juvenile rainbow trout to fasting and swimming activity: Effects on body composition and condition indices

    USGS Publications Warehouse

    Simpkins, D.G.; Hubert, W.A.; Del Rio, C.M.; Rule, D.C.

    2003-01-01

    The physiological traits that allow fish to survive periods of limited food resources are poorly understood. We assessed changes in proximate body composition, relative organ mass, blood metabolites, and relative weight (Wr) of sedentary and actively swimming (15 cm/s) juvenile rainbow trout (154-182 mm total length) over 147 d of fasting. Fasting caused measurable responses that were augmented when fish were swimming. Lipids and plasma triacylglycerides declined over time. Proteins were catabolized simultaneously with lipid reserves, but ammonia concentrations in plasma did not increase. The liver somatic index (LSI) did not change substantially over 105 d, suggesting that gluconeogenesis maintained blood glucose concentrations and hepatic glycogen reserves for a substantial period of fasting. The gut somatic index (GSI) and Wr declined linearly during fasting, but the LSI did not decline until after 105 d of fasting. Consequently, the use of different body condition indices could lead to different conclusions about the condition of juvenile rainbow trout. Swimming activity caused fish to have lower lipid and protein reserves than those of sedentary fish. No mortalities were observed among sedentary fish, but mortalities occurred among actively swimming fish after 97 d of fasting when 3.2% or less lipid remained in their bodies. Body condition indices did not account for differences in proximate body composition between sedentary and actively swimming fish and were relatively poor predictors of lipid content and risk of mortality. The probability of mortality was most accurately predicted by percent lipid content. Therefore, we suggest that fisheries scientists consider using percent lipid content when evaluating the physiological status and risk of mortality due to starvation among juvenile rainbow trout.

  11. A Comparative Analysis of Swimming Styles in Competitive Swimming

    NASA Astrophysics Data System (ADS)

    von Loebbecke, Alfred; Mittal, Rajat; Gupta, Varun; Mark, Russell

    2007-11-01

    High-fidelity numerical simulations are being used to conduct a critical evaluation of swimming strokes in competitive swimming. We combine computational fluid dynamics (CFD), laser body scans, animation software, and video footage to develop accurate models of Olympic level swimmers and use these to examine contrasting styles of the dolphin kick as well as the arm strokes in back and front crawl stroke. In the dolphin kick, the focus is on examining the effects of Strouhal number, kick amplitude, frequency, and technique on thrust production. In the back stroke, we examine the performance of the so called ``flat stroke'' versus the ``deep catch,'' The most important aspect that separates the two major types of back stroke is the alignment or angle of attack of the palm during the stroke. In one style of front crawl arm stroke, there is greater elbow joint flexion, shoulder abduction and sculling whereas the other style consists of a straight arm pull dominated by simple shoulder flexion. Underlying the use of these two styles is the larger and more fundamental issue of the role of lift versus drag in thrust production and we use the current simulations to examine this issue in detail.

  12. Oscillatory Flows Induced by Swimming Microorganisms in Two-dimensions

    NASA Astrophysics Data System (ADS)

    Guasto, Jeffrey S.; Johnson, Karl A.; Gollub, J. P.

    2010-11-01

    We present the first time-resolved measurements of the oscillatory velocity field induced by swimming unicellular microorganisms. Confinement of the green alga Chlamydomonas reinhardtii in stabilized thin liquid films allows simultaneous tracking of cells and tracer particles. The phase-resolved velocity field reveals complex time-dependent flow structures, which evolve throughout the beat cycle of the organism, and the fluid velocity scales inversely with distance. The instantaneous mechanical power generated by the cells is measured from the velocity fields via the viscous dissipation and scales with the square of the swimmer speed. The peak power is about 15 fW, and the dissipation per cycle is more than four times what steady swimming would require. These observations carry important implications for the interpretation and modeling of transport processes, locomotion, and flagellar mechanics.

  13. Optimal Swimming with a Burst-and-Coast Behaviour

    NASA Astrophysics Data System (ADS)

    Akoz, Emre; Moored, Keith

    2014-11-01

    Swimming animals are typically assumed to be continuously adding power to the fluid throughout a period of motion. On the other hand, animals have been observed using a non-continuously powered motion described as a burst-and-coast or burst-and-glide behavior. When animals use a non-continuously powered motion it is estimated that their cost of transport is reduced by as much as 45%. However, there are competing mechanisms in the literature that lead to this conclusion. The present study aims to identify the underlying mechanism of burst-and-coast energy savings and to quantify the scaling of optimal motions. A two-dimensional boundary element method approach is used to quantify the performance and wake structure of a free-swimming pitching panel operating with a burst-and-coast behavior. Supported by the Office of Naval Research under Program Director Dr. Bob Brizzolara, MURI Grant Number N00014-14-1-0533.

  14. Solar heater for swimming pools

    SciTech Connect

    Babcock, H.W.

    1984-12-04

    A solar heater for swimming pools is provided having one or more heating panels installable on a roof or the like and arranged to discharge into a pool equipped with an apron without need for disturbing or obstructing the apron. This is accomplished by the provision of an elevated bistable dumper adjacent the perimeter of the apron having a dispensing spout normally inclined upwardly but pivoting at intervals to discharge into the pool across the apron without obstructing it. Water to be heated is diverted from the pool filtering system to the solar heater via a pressure regulator and a solar responsive flow control.

  15. Arm insulation and swimming in cold water.

    PubMed

    Lounsbury, David S; Ducharme, Michel B

    2008-09-01

    To test whether adding insulation to the arms would improve cold water swimming performance by delaying swimming failure (SF). Novice (n = 7) and expert (n = 8) swimmers, clothed and equipped with a personal flotation device, each performed two trials in a swimming flume filled with 10 degrees C water. During free swimming (FS), subjects performed swimming until failure, followed by the Heat Escape Lessening Posture. In free swimming with additional insulation (FSA), subjects wore custom-fitted armbands. Trials ended when rectal temperature decreased to 34 degrees C or after 2 h of immersion. Measurements included: rectal and skin temperatures, heat flow, and various appraisals of swimming performance. FSA was thermally advantageous versus FS. Rectal temperature cooling rates during swimming (dT/dt Swim) were faster for FS compared to FSA (0.050 +/- 0.007 degrees C min(-1) vs. 0.042 +/- 0.006 degrees C min(-1), P < 0.01). Armbands maintained arm skin temperature about 10 degrees C warmer, for approximately 70 min (P < 0.001). Although additional insulation did not greatly improve physical performances, video analysis showed that swimming technique in FSA was maintained 10-15% better than in FS between minutes 30 and 50 (P < 0.001). SF was achieved in 5/30 trials, with increases in stroke rate (6.6 str min(-1)) and decreases in stroke length (0.24 m str(-1)) observed. In this simulation of cold water swimming survival, equipping subjects with neoprene armbands appears to have partially preserved muscle function, but with unimpressive effects on overall performance. SF is a complex entity, but is evidently related to both triceps skinfold and arm girth. PMID:18309510

  16. Impaired anterior swim bladder inflation following exposure to the thyroid peroxidase inhibitor 2-mercaptobenzothiazole part I: Fathead minnow.

    PubMed

    Nelson, Krysta R; Schroeder, Anthony L; Ankley, Gerald T; Blackwell, Brett R; Blanksma, Chad; Degitz, Sigmund J; Flynn, Kevin M; Jensen, Kathleen M; Johnson, Rodney D; Kahl, Michael D; Knapen, Dries; Kosian, Patricia A; Milsk, Rebecca Y; Randolph, Eric C; Saari, Travis; Stinckens, Evelyn; Vergauwen, Lucia; Villeneuve, Daniel L

    2016-04-01

    In the present study, a hypothesized adverse outcome pathway linking inhibition of thyroid peroxidase (TPO) activity to impaired swim bladder inflation was investigated in two experiments in which fathead minnows (Pimephales promelas) were exposed to 2-mercaptobenzothiazole (MBT). Continuous exposure to 1mg MBT/L for up to 22 days had no effect on inflation of the posterior chamber of the swim bladder, which typically inflates around 6 days post fertilization (dpf), a period during which maternally-derived thyroid hormone is presumed to be present. In contrast, inflation of the anterior swim bladder, which occurs around 14dpf, was impacted. Specifically, at 14dpf, approximately 50% of fish exposed to 1mg MBT/L did not have an inflated anterior swim bladder. In fish exposed to MBT through 21 or 22dpf, the anterior swim bladder was able to inflate, but the ratio of the anterior/posterior chamber length was significantly reduced compared to controls. Both abundance of thyroid peroxidase mRNA and thyroid follicle histology suggest that fathead minnows mounted a compensatory response to the presumed inhibition of TPO activity by MBT. Time-course characterization showed that fish exposed to MBT for at least 4 days prior to normal anterior swim bladder inflation had significant reductions in anterior swim bladder size, relative to the posterior chamber, compared to controls. These results, along with similar results observed in zebrafish (see part II, this issue) are consistent with the hypothesis that thyroid hormone signaling plays a significant role in mediating anterior swim bladder inflation and development in cyprinids, and that role can be disrupted by exposure to thyroid hormone synthesis inhibitors. Nonetheless, possible thyroid-independent actions of MBT on anterior swim bladder inflation cannot be ruled out based on the present results. Overall, although anterior swim bladder inflation has not been directly linked to survival as posterior swim bladder inflation

  17. Noiseless propulsion for swimming robotic structures using polyelectrolyte ion-exchange membrane

    NASA Astrophysics Data System (ADS)

    Mojarrad, Mehran; Shahinpoor, Mohsen

    1996-02-01

    In this paper a NafionTM polyelectrolyte ion-exchange membrane (IEM) was used as a propulsion fin for robotic swimming structures such as a boat or fish-like object swimming in water or aqueous medium. The Nafion membrane was chemically plated with platinum. The resulting membrane was cut in a strip to resemble a fish-like caudal fin for propulsion. A small function generator circuit was designed and built to produce approximately plus or minus 2.0 V amplitude square wave at varying frequency up to 50 Hz. The circuit board was mounted on a buoyant styrofoam shaped like a boat or a tadpole. The fin was attached to the rear of the boat. By setting the signal frequency to the desired value and thereby setting the frequency of bending oscillation of the membrane, a proportional forward propulsion speed could be obtained. The speed was then measured using a high speed camera. Several theoretical hydrodynamic models were then presented to characterize speed-frequency of the forward motion using available theories on biological fish motion. The results were compared to experimental data which showed close agreement. It turned out that the forward speed of the object was directly proportional to the product of frequency and amplitude of the fin oscillation as in biological fishes. This relation was further simplified by keeping the voltage constant and therefore amplitude of the oscillation. The proportionality constant could be measured for a known geometry of the fin-boat assembly and reactivity of the Nafion membrane used. The system as a whole presented an autonomous robotic swimming structure with frequency modulated propulsion to investigate application of polyelectrolyte hydrogel membranes and their effect on hydrodynamic behavior of an undulating swimming object. As in fishes the thrust force of the robot was generated by evolution of vortices on the sides of the undulating fin. For a constant forward speed, this thrust is equal to the drag force due to geometry

  18. Analysis of ice-binding sites in fish type II antifreeze protein by quantum mechanics.

    PubMed Central

    Cheng, Yuhua; Yang, Zuoyin; Tan, Hongwei; Liu, Ruozhuang; Chen, Guangju; Jia, Zongchao

    2002-01-01

    Many organisms living in cold environments can survive subzero temperatures by producing antifreeze proteins (AFPs) or antifreeze glycoproteins. In this paper we investigate the ice-binding surface of type II AFP by quantum mechanical methods, which, to the best of our knowledge, represents the first time that molecular orbital computational approaches have been applied to AFPs. Molecular mechanical approaches, including molecular docking, energy minimization, and molecular dynamics simulation, were used to obtain optimal systems for subsequent quantum mechanical analysis. We selected 17 surface patches covering the entire surface of the type II AFP and evaluated the interaction energy between each of these patches and two different ice planes using semi-empirical quantum mechanical methods. We have demonstrated the weak orbital overlay phenomenon and the change of bond orders in ice. These results consistently indicate that a surface patch containing 19 residues (K37, L38, Y20, E22, Y21, I19, L57, T56, F53, M127, T128, F129, R17, C7, N6, P5, G10, Q1, and W11) is the most favorable ice-binding site for both a regular ice plane and an ice plane where water O atoms are randomly positioned. Furthermore, for the first time the computation results provide new insights into the weakening of the ice lattice upon AFP binding, which may well be a primary factor leading to AFP-induced ice growth inhibition. PMID:12324437

  19. Compensatory mechanisms in fish populations: Literature reviews: Volume 1, Critical evaluation of case histories of fish populations experiencing chronic exploitation or impact: Final report

    SciTech Connect

    Saila, S.B.; Chen, X.; Erzini, K.; Martin, B.

    1987-05-01

    This study includes case histories of certain fish species which are experiencing chronic perturbations and related literature pertaining to compensation processes. ''Compensation'' has been defined as the ability of fish to offset the population reduction caused by natural or man-induced stresses. Certain compensation methods are widely accepted, and include cannibalism, competition, disease, growth and predation, among others. These compensation methods are examined in relation to each fish species included in the study. Stock-recruit relationships and empirical observations of changes in growth and mortality have been the focus of much of the background on compensation. One of the conclusions drawn from this study is that a significant amount of recruitment variability exists and can be attributed to environmental (rather than compensatory) factors. The stock-recruitment problem appears to be the most significant scientific problem related to compensation in the types of fish included in this study. Results of the most recent studies of the American shad support this theory. Life histories, breeding biology and other pertinent data relating to each species included in the study will be found in the appendices.

  20. Effect of swimming exercise on three-dimensional trabecular bone microarchitecture in ovariectomized rats.

    PubMed

    Ju, Yong-In; Sone, Teruki; Ohnaru, Kazuhiro; Tanaka, Kensuke; Fukunaga, Masao

    2015-11-01

    Swimming is generally considered ineffective for increasing bone mass in humans, at least compared with weight-bearing sports. However, swimming exercise has sometimes been shown to have a strong positive effect on bone mass in small animals. This study investigated the effects of swimming on bone mass, strength, and microarchitecture in ovariectomized (OVX) rats. OVX or sham operations were performed on 18-wk-old female Fisher 344 rats. Rats were randomly divided into four groups: sham sedentary (Sham-CON), sham swimming exercised (Sham-SWI), OVX sedentary (OVX-CON), and OVX swimming exercised (OVX-SWI). Rats in exercise groups performed swimming in a water bath for 60 min/day, 5 days/wk, for 12 wk. Bone mineral density (BMD) in right femurs was analyzed using dual-energy X-ray absorptiometry. Three-dimensional trabecular architecture at the distal femoral metaphysis was analyzed using microcomputed tomography (μCT). Geometrical properties of diaphyseal cortical bone were evaluated in the midfemoral region using μCT. The biomechanical properties of femurs were analyzed using three-point bending. Femoral BMD was significantly decreased following ovariectomy. This change was suppressed by swimming. Trabecular bone thickness, number, and connectivity were decreased by ovariectomy, whereas structure model index (i.e., ratio of rod-like to plate-like trabeculae) increased. These changes were also suppressed by swimming exercise. Femurs displayed greater cortical width and maximum load in SWI groups than in CON groups. Together, these results demonstrate that swimming exercise drastically alleviated both OVX-induced decreases in bone mass and mechanical strength and the deterioration of trabecular microarchitecture in rat models of osteoporosis. PMID:26338454

  1. 36 CFR 327.5 - Swimming.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Swimming. (a) Swimming, wading, snorkeling or scuba diving at one's own risk is permitted, except at... Commander. (b) An international diver down, or inland diving flag must be displayed during underwater activities. (c) Diving, jumping or swinging from trees, bridges or other structures which cross or...

  2. 36 CFR 327.5 - Swimming.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Swimming. (a) Swimming, wading, snorkeling or scuba diving at one's own risk is permitted, except at... Commander. (b) An international diver down, or inland diving flag must be displayed during underwater activities. (c) Diving, jumping or swinging from trees, bridges or other structures which cross or...

  3. Basic Land Drills for Swimming Stroke Acquisition

    ERIC Educational Resources Information Center

    Zhang, Peng

    2014-01-01

    Teaching swimming strokes can be a challenging task in physical education. The purpose of the article is to introduce 12 on land drills that can be utilized to facilitate the learning of swimming strokes, including elementary back stroke, sidestroke, front crawl, back stroke, breaststroke, and butterfly. Each drill consists of four components…

  4. Swimming Motility Reduces Deposition to Silica Surfaces

    SciTech Connect

    Lu, Nanxi; Massoudieh, Arash; Liang, Xiaomeng; Hu, Dehong; Kamai, Tamir; Ginn, Timothy R.; Zilles, Julie L.; Nguyen, Thanh H.

    2015-01-01

    The role of swimming motility on bacterial transport and fate in porous media was evaluated. We present microscopic evidence showing that strong swimming motility reduces attachment of Azotobacter vinelandii cells to silica surfaces. Applying global and cluster statistical analyses to microscopic videos taken under non-flow conditions, wild type, flagellated A. vinelandii strain DJ showed strong swimming ability with an average speed of 13.1 μm/s, DJ77 showed impaired swimming averaged at 8.7 μm/s, and both the non-flagellated JZ52 and chemically treated DJ cells were non-motile. Quantitative analyses of trajectories observed at different distances above the collector of a radial stagnation point flow cell (RSPF) revealed that both swimming and non-swimming cells moved with the flow when at a distance of at least 20 μm from the collector surface. Near the surface, DJ cells showed both horizontal and vertical movement diverging them from reaching surfaces, while chemically treated DJ cells moved with the flow to reach surfaces, suggesting that strong swimming reduced attachment. In agreement with the RSPF results, the deposition rates obtained for two-dimensional multiple-collector micromodels were also lowest for DJ, while DJ77 and JZ52 showed similar values. Strong swimming specifically reduced deposition on the upstream surfaces of the micromodel collectors.

  5. Teaching Swimming Using a Backward Chain Sequence.

    ERIC Educational Resources Information Center

    Killian, Kenneth J.

    1988-01-01

    The backward chaining instructional method, based on behavioral learning principles, offers swimming instructors an alternative to traditional methods of teaching swimming skills by breaking down the skill into a number of tasks or steps and teaching them in reverse sequence. (CB)

  6. Swim pressure: stress generation in active matter.

    PubMed

    Takatori, S C; Yan, W; Brady, J F

    2014-07-11

    We discover a new contribution to the pressure (or stress) exerted by a suspension of self-propelled bodies. Through their self-motion, all active matter systems generate a unique swim pressure that is entirely athermal in origin. The origin of the swim pressure is based upon the notion that an active body would swim away in space unless confined by boundaries-this confinement pressure is precisely the swim pressure. Here we give the micromechanical basis for the swim stress and use this new perspective to study self-assembly and phase separation in active soft matter. The swim pressure gives rise to a nonequilibrium equation of state for active matter with pressure-volume phase diagrams that resemble a van der Waals loop from equilibrium gas-liquid coexistence. Theoretical predictions are corroborated by Brownian dynamics simulations. Our new swim stress perspective can help analyze and exploit a wide class of active soft matter, from swimming bacteria to catalytic nanobots to molecular motors that activate the cellular cytoskeleton. PMID:25062240

  7. 36 CFR 327.5 - Swimming.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Swimming. (a) Swimming, wading, snorkeling or scuba diving at one's own risk is permitted, except at... Commander. (b) An international diver down, or inland diving flag must be displayed during underwater activities. (c) Diving, jumping or swinging from trees, bridges or other structures which cross or...

  8. Assessment of Swimming in Physical Education

    ERIC Educational Resources Information Center

    Grosse, Susan J.

    2005-01-01

    This article presents an excerpt from the book "Assessment of Swimming in Physical Education" by Susan J. Grosse. In this excerpt, the different methods of assessment are discussed. Each type of assessment presented in the book has a place in swim curriculum. Assessments can measure form, skill application, knowledge, behavior, attitude, or…

  9. Teaching the Physically Handicapped to Swim.

    ERIC Educational Resources Information Center

    Anderson, William

    First principles of teaching swimming to the handicapped are reviewed; attention is given to children with cerebral palsy or muscular dystrophy, physical handicaps, blindness, and deafness. Swimming strokes, suggested exercises, group teaching, and a typical sequence of lessons and exercises are considered. Some case histories and a plan for a…

  10. A Training Program for Swimming Pool Operators.

    ERIC Educational Resources Information Center

    Pope, James R., Jr.; Mihalik, Brian J.

    1985-01-01

    In the United States today, there is a dramatic shortage of qualified public swimming pool operators. This article describes a training program initiated in South Carolina to serve the needs of everyone responsible for and involved in the safe operation and management of a public swimming pool. (MT)

  11. Teaching Swimming--The Coach's Way.

    ERIC Educational Resources Information Center

    DeMarie, John

    1983-01-01

    Coaches of competitive swimmers use many types of equipment and teaching techniques that should also be available to physical educators who teach swimming. Equipment, such as goggles, hand paddles, swim benches, fins, kickboards, pace clocks, and pull buoys, and training methods used in conjunction with them, are discussed. (PP)

  12. Forced sustained swimming exercise at optimal speed enhances growth of juvenile yellowtail kingfish (Seriola lalandi).

    PubMed

    Palstra, Arjan P; Mes, Daan; Kusters, Kasper; Roques, Jonathan A C; Flik, Gert; Kloet, Kees; Blonk, Robbert J W

    2014-01-01

    Swimming exercise at optimal speed may optimize growth performance of yellowtail kingfish in a recirculating aquaculture system. Therefore, optimal swimming speeds (U opt in m s(-1) or body lengths s(-1), BL s(-1)) were assessed and then applied to determine the effects of long-term forced and sustained swimming at U opt on growth performance of juvenile yellowtail kingfish. U opt was quantified in Blazka-type swim-tunnels for 145, 206, and 311 mm juveniles resulting in values of: (1) 0.70 m s(-1) or 4.83 BL s(-1), (2) 0.82 m s(-1) or 3.25 BL s(-1), and (3) 0.85 m s(-1) or 2.73 BL s(-1). Combined with literature data from larger fish, a relation of U opt (BL s(-1)) = 234.07(BL)(-0.779) (R (2) = 0.9909) was established for this species. Yellowtail kingfish, either forced to perform sustained swimming exercise at an optimal speed of 2.46 BL s(-1) ("swimmers") or allowed to perform spontaneous activity at low water flow ("resters") in a newly designed 3600 L oval flume (with flow created by an impeller driven by an electric motor), were then compared. At the start of the experiment, ten fish were sampled representing the initial condition. After 18 days, swimmers (n = 23) showed a 92% greater increase in BL and 46% greater increase in BW as compared to resters (n = 23). As both groups were fed equal rations, feed conversion ratio (FCR) for swimmers was 1.21 vs. 1.74 for resters. Doppler ultrasound imaging showed a statistically significant higher blood flow (31%) in the ventral aorta of swimmers vs. resters (44 ± 3 vs. 34 ± 3 mL min(-1), respectively, under anesthesia). Thus, growth performance can be rapidly improved by optimal swimming, without larger feed investments. PMID:25620933

  13. Forced sustained swimming exercise at optimal speed enhances growth of juvenile yellowtail kingfish (Seriola lalandi)

    PubMed Central

    Palstra, Arjan P.; Mes, Daan; Kusters, Kasper; Roques, Jonathan A. C.; Flik, Gert; Kloet, Kees; Blonk, Robbert J. W.

    2015-01-01

    Swimming exercise at optimal speed may optimize growth performance of yellowtail kingfish in a recirculating aquaculture system. Therefore, optimal swimming speeds (Uopt in m s−1 or body lengths s−1, BL s−1) were assessed and then applied to determine the effects of long-term forced and sustained swimming at Uopt on growth performance of juvenile yellowtail kingfish. Uopt was quantified in Blazka-type swim-tunnels for 145, 206, and 311 mm juveniles resulting in values of: (1) 0.70 m s−1 or 4.83 BL s−1, (2) 0.82 m s−1 or 3.25 BL s−1, and (3) 0.85 m s−1 or 2.73 BL s−1. Combined with literature data from larger fish, a relation of Uopt (BL s−1) = 234.07(BL)−0.779 (R2 = 0.9909) was established for this species. Yellowtail kingfish, either forced to perform sustained swimming exercise at an optimal speed of 2.46 BL s−1 (“swimmers”) or allowed to perform spontaneous activity at low water flow (“resters”) in a newly designed 3600 L oval flume (with flow created by an impeller driven by an electric motor), were then compared. At the start of the experiment, ten fish were sampled representing the initial condition. After 18 days, swimmers (n = 23) showed a 92% greater increase in BL and 46% greater increase in BW as compared to resters (n = 23). As both groups were fed equal rations, feed conversion ratio (FCR) for swimmers was 1.21 vs. 1.74 for resters. Doppler ultrasound imaging showed a statistically significant higher blood flow (31%) in the ventral aorta of swimmers vs. resters (44 ± 3 vs. 34 ± 3 mL min−1, respectively, under anesthesia). Thus, growth performance can be rapidly improved by optimal swimming, without larger feed investments. PMID:25620933

  14. Resurgence in Siamese fighting fish, Betta splendens.

    PubMed

    da Silva, Stephanie P; Cançado, Carlos R X; Lattal, Kennon A

    2014-03-01

    Resurgence of previously reinforced responding was investigated in male Siamese fighting fish (Betta splendens). Swimming through a ring produced 15-s mirror presentations according to, with different fish, either a fixed-ratio 1 or a variable-interval 60-s schedule of reinforcement. When responding was stable, a differential-reinforcement-of-other-behavior schedule was substituted for the mirror-presentation schedule. Following this, mirror presentations were discontinued (extinction). During this latter phase, there were transient increases in the ring-swim response relative to the frequency of such responding during the differential-reinforcement-of-other behavior schedule. Resurgence was similar for the fish exposed previously to the fixed-ratio or to the variable-interval schedule. These results extend to Siamese fighting fish a well-established behavioral phenomenon previously not observed in this species or with this response topography, and only rarely reported following the removal of a non-consumable reinforcer. PMID:24462710

  15. Swimming

    MedlinePlus

    ... dad to make sure your flotation devices are Coast Guard-approved. Walk slowly in the pool area. Don' ... life jacket. (Again, the life jacket should be Coast Guard-approved.) Even if you are a good swimmer, ...

  16. Undulatory swimming in non-Newtonian fluids

    NASA Astrophysics Data System (ADS)

    Ardekani, Arezoo; Li, Gaojin

    2015-11-01

    Microorganisms often swim in complex fluids exhibiting both elasticity and shear-thinning viscosity. The motion of low Reynolds number swimmers in complex fluids is important for better understanding the migration of sperms and formation of bacterial biofilms. In this work, we numerically investigate the effects of non-Newtonian fluid properties, including shear-thinning and elasticity, on the undulatory locomotion. Our results show that elasticity hinders the swimming speed, but a shear-thinning viscosity in the absence of elasticity enhances the speed. The combination of the two effects hinders the swimming speed. The swimming boost in a shear-thinning fluid occurs even for an infinitely long flagellum. The swimming speed has a maximum, whose value depends on the flagellum oscillation amplitude and fluid rheological properties. The power consumption, on the other hand, follows a universal scaling law. This work is supported by NSF CBET-1445955 and Indiana CTSI TR001108.

  17. Undulatory Swimming in Shear-thinning Fluids

    NASA Astrophysics Data System (ADS)

    Shen, Xiaoning; Gagnon, David; Arratia, Paulo

    2012-11-01

    Many fluids in which microorganisms move, feed, and reproduce possess shear-rate dependent viscosity behavior (e.g. shear-thinning). Such fluids include wet soil, clay suspension, mucus, and gels. In this talk, we experimentally investigate the effects of shear-rate dependent viscosity on the swimming behavior of the nematode Caenorhabditis elegans using velocimetry and tracking methods. Here, aqueous solutions of xanthan gum, which is a rod-like stiff polymer, are used with concentrations varying from the semi-dilute to the concentrated regime. The data is compared to swimming in simple, Newtonian fluids. We find that the nematode swims at an approximately constant speed in the semi-dilute regime. Surprisingly, the nematode exhibits 40% increases in swimming speed once immersed in a concentrated solution. The enhancement in swimming speed seems to be related to the dynamics of rod-like polymer networks formed in concentrated solutions. This work was supported by NSF-CAREER (CBET)-0954084.

  18. Rainbow trout consume less oxygen in turbulence: the energetics of swimming behaviors at different speeds

    PubMed Central

    Taguchi, Masashige; Liao, James C.

    2011-01-01

    SUMMARY Measuring the rate of consumption of oxygen () during swimming reveals the energetics of fish locomotion. We show that rainbow trout have substantially different oxygen requirements for station holding depending on which hydrodynamic microhabitats they choose to occupy around a cylinder. We used intermittent flow respirometry to show that an energetics hierarchy, whereby certain behaviors are more energetically costly than others, exists both across behaviors at a fixed flow velocity and across speeds for a single behavior. At 3.5 L s–1 (L is total body length) entraining has the lowest , followed by Kármán gaiting, bow waking and then free stream swimming. As flow speed increases the costs associated with a particular behavior around the cylinder changes in unexpected ways compared with free stream swimming. At times, actually decreases as flow velocity increases. Entraining demands the least oxygen at 1.8 L s–1 and 3.5 L s–1, whereas bow waking requires the least oxygen at 5.0 L s–1. Consequently, a behavior at one speed may have a similar cost to another behavior at another speed. We directly confirm that fish Kármán gaiting in a vortex street gain an energetic advantage from vortices beyond the benefit of swimming in a velocity deficit. We propose that the ability to exploit velocity gradients as well as stabilization costs shape the complex patterns of oxygen consumption for behaviors around cylinders. Measuring for station holding in turbulent flows advances our attempts to develop ecologically relevant approaches to evaluating fish swimming performance. PMID:21490251

  19. Sturgeon hatching enzyme and the mechanism of egg envelope digestion: Insight into changes in the mechanism of egg envelope digestion during the evolution of ray-finned fish.

    PubMed

    Nagasawa, Tatsuki; Kawaguchi, Mari; Sano, Kaori; Yasumasu, Shigeki

    2015-12-01

    We investigated the evolution of the hatching enzyme gene using bester sturgeon (hybrid of Acipencer ruthenus and Huso huso), a basal member of ray-finned fishes. We purified the bester hatching enzyme from hatching liquid, yielding a single band on SDS-PAGE, then isolated its cDNA from embryos by PCR. The sturgeon hatching enzyme consists of an astacin family protease domain and a CUB domain. The CUB domains are present in frog and bird hatching enzymes, but not in teleostei, suggesting that the domain structure of sturgeon hatching enzyme is the tetrapod type. The purified hatching enzyme swelled the egg envelope, and selectively cleaved one of five egg envelope proteins, ZPAX. Xenopus hatching enzyme preferentially digests ZPAX, thus, the egg envelope digestion process is conserved between amphibians and basal ray-finned fish. Teleostei hatching enzymes cleave the repeat sequences at the N-terminal region of ZPB and ZPC, suggesting that the targets of the teleostei hatching enzymes differ from those of amphibians and sturgeons. Such repeat sequences were not found in the N-terminal region of ZPB and ZPC of amphibians and sturgeons. Our results suggest that the change in substrates of the hatching enzymes was accompanied by the mutation of the amino acid sequence of N-terminal regions of ZPB and ZPC. We conclude that the changes in the mechanism of egg envelope digestion, including the change in the domain structure of the hatching enzymes and the switch in substrate, occurred during the evolution of teleostei, likely triggered by the teleost-specific third whole genome duplication. J. Exp. Zool. (Mol. Dev. Evol.) 324B: 720-732, 2015. © 2015 Wiley Periodicals, Inc. PMID:26514945

  20. Numerical modelling of chirality-induced bi-directional swimming of artificial flagella.

    PubMed

    Namdeo, S; Khaderi, S N; Onck, P R

    2014-02-01

    Biomimetic micro-swimmers can be used for various medical applications, such as targeted drug delivery and micro-object (e.g. biological cells) manipulation, in lab-on-a-chip devices. Bacteria swim using a bundle of flagella (flexible hair-like structures) that form a rotating cork-screw of chiral shape. To mimic bacterial swimming, we employ a computational approach to design a bacterial (chirality-induced) swimmer whose chiral shape and rotational velocity can be controlled by an external magnetic field. In our model, we numerically solve the coupled governing equations that describe the system dynamics (i.e. solid mechanics, fluid dynamics and magnetostatics). We explore the swimming response as a function of the characteristic dimensionless parameters and put special emphasis on controlling the swimming direction. Our results provide fundamental physical insight on the chirality-induced propulsion, and it provides guidelines for the design of magnetic bi-directional micro-swimmers. PMID:24511253

  1. Comparing effects of transmitters within and among populations: application to swimming performance of juvenile Chinook salmon

    USGS Publications Warehouse

    Perry, Russell W.; Plumb, John M.; Fielding, Scott D.; Adams, Noah S.; Rondorf, Dennis W.

    2013-01-01

    The sensitivity of fish to a transmitter depends on factors such as environmental conditions, fish morphology, life stage, rearing history, and tag design. However, synthesizing general trends across studies is difficult because each study focuses on a particular performance measure, species, life stage, and transmitter model. These differences motivated us to develop simple metrics that allow effects of transmitters to be compared among different species, populations, or studies. First, we describe how multiple regression analysis can be used to quantify the effect of tag burden (transmitter mass relative to fish mass) on measures of physiological performance. Next, we illustrate how the slope and intercept parameters can be used to calculate two summary statistics: θ, which estimates the tag burden threshold above which the performance of tagged fish begins to decline relative to untagged fish; and k, which measures the percentage change in performance per percentage point increase in tag burden. When θ = 0, k provides a single measure of the tag's effect that can be compared among species, populations, or studies. We apply this analysis to two different experiments that measure the critical swimming speed (U crit) of tagged juvenile Chinook Salmon Oncorhynchus tshawytscha. In both experiments, U crit declined as tag burden increased, but we found no significant threshold in swimming performance. Estimates of θ ranged from −0.6% to 2.1% among six unique treatment groups, indicating that swimming performance began to decline at a relatively low tag burden. Estimates of k revealed that U crit of tagged fish declined by −2.68% to −4.86% for each 1% increase in tag burden. Both θ and k varied with the tag's antenna configuration, tag implantation method, and posttagging recovery time. Our analytical approach can be used to gain insights across populations to better understand factors affecting the ability of fish to carry a transmitter.

  2. Examining dolphin hydrodynamics provides clues to calf-loss during tuna fishing

    PubMed Central

    Moore, Pete

    2004-01-01

    A combination of mathematical modeling and direct observation of the swimming behavior of dolphin mother-calf pairs has shown how the calf can gain much of the energy required for swimming if it is positioned correctly relative to the mother, a situation that may be disrupted during the chases that result from tuna-fishing practices. PMID:15132739

  3. Ontogeny of swimming speed, schooling behaviour and jellyfish avoidance by Japanese anchovy Engraulis japonicus.

    PubMed

    Masuda, R

    2011-05-01

    The ontogeny of swimming speed, schooling behaviour and jellyfish avoidance was studied in hatchery-reared Japanese anchovy Engraulis japonicus to compare its life-history strategy with two other common pelagic fishes, jack mackerel Trachurus japonicus and chub mackerel Scomber japonicus. Cruise swimming speed of E. japonicus increased allometrically from 1·4 to 3·9 standard length (L(S) ) per s (L(S) s(-1) ) from early larval to metamorphosing stage. Burst swimming speed also increased from 6·1 to 28 L(S) s(-1) in these stages. Cruise speed was inferior to that of S. japonicus, as was burst speed to that of T. japonicus. Engraulis japonicus larvae were highly vulnerable to predation by moon jellyfish Aurelia aurita and were readily eaten until they reached 23 mm L(S) , but not at 26 mm L(S) . Schooling behaviour (indicated by parallel swimming) started at c. 17 mm L(S) . Average distance to the nearest neighbour was shorter than values reported in other pelagic fishes. The relatively low predator avoidance capability of E. japonicus may be compensated for by their transparent and thus less conspicuous body, in addition to their early maturation and high fecundity. PMID:21539545

  4. Stress response of lead-exposed rainbow trout (Oncorhynchus mykiss) during swimming performance and hypoxia challenges

    SciTech Connect

    Phillips, K.A. |; Caldwell, C.A.; Sandheinrich, M.B.

    1995-12-31

    Contaminants often invoke a stress response in aquatic organisms, and may compromise their capacity to respond to secondary stressors. This may reduce growth, reproduction and survival. The authors objectives were to assess the effects of lead and secondary stressors on hematology and blood chemistry of rainbow trout. After a 7 to 8-week aqueous exposure to Pb(100{micro}g/L), rainbow trout were challenged with forced swimming or hypoxia. Lead significantly reduced concentrations of 5-aminolevulinic acid dehydratase (ALAD), but not other constituents in the blood. Lead did not affect the swimming endurance of the fish. Hematocrit, mean cell hemoglobin content, and mean cell volume were significantly lower in Pb-exposed trout following the swimming challenge. Although hypoxia resulted in increased hematocrit and plasma glucose concentrations, there were no significant differences between the Pb and control groups. Hypoxia did not affect plasma chloride concentrations, although concentrations increased in Pb-exposed trout. There was no difference in lactic acid concentrations between Pb-exposed and control fish after forced swimming or hypoxia.

  5. Analysis of the Actin–Myosin II System in Fish Epidermal Keratocytes: Mechanism of Cell Body Translocation

    PubMed Central

    Svitkina, Tatyana M.; Verkhovsky, Alexander B.; McQuade, Kyle M.; Borisy, Gary G.

    1997-01-01

    While the protrusive event of cell locomotion is thought to be driven by actin polymerization, the mechanism of forward translocation of the cell body is unclear. To elucidate the mechanism of cell body translocation, we analyzed the supramolecular organization of the actin–myosin II system and the dynamics of myosin II in fish epidermal keratocytes. In lamellipodia, long actin filaments formed dense networks with numerous free ends in a brushlike manner near the leading edge. Shorter actin filaments often formed T junctions with longer filaments in the brushlike area, suggesting that new filaments could be nucleated at sides of preexisting filaments or linked to them immediately after nucleation. The polarity of actin filaments was almost uniform, with barbed ends forward throughout most of the lamellipodia but mixed in arc-shaped filament bundles at the lamellipodial/cell body boundary. Myosin II formed discrete clusters of bipolar minifilaments in lamellipodia that increased in size and density towards the cell body boundary and colocalized with actin in boundary bundles. Time-lapse observation demonstrated that myosin clusters appeared in the lamellipodia and remained stationary with respect to the substratum in locomoting cells, but they exhibited retrograde flow in cells tethered in epithelioid colonies. Consequently, both in locomoting and stationary cells, myosin clusters approached the cell body boundary, where they became compressed and aligned, resulting in the formation of boundary bundles. In locomoting cells, the compression was associated with forward displacement of myosin features. These data are not consistent with either sarcomeric or polarized transport mechanisms of cell body translocation. We propose that the forward translocation of the cell body and retrograde flow in the lamellipodia are both driven by contraction of an actin–myosin network in the lamellipodial/cell body transition zone. PMID:9334344

  6. Habituation of Backward Escape Swimming in the Marbled Crayfish.

    PubMed

    Kasuya, Azusa; Nagayama, Toshiki

    2016-02-01

    In the present study, we performed behavioral analyses of the habituation of backward escape swimming in the marbled crayfish, Procambarus fallax. Application of rapid mechanical stimulation to the rostrum elicited backward swimming following rapid abdominal flexion of crayfish. Response latency was very short-tens of msec-suggesting that backward swimming is mediated by MG neurons. When stimulation was repeated with 10 sec interstimulus intervals the MG-like tailflip did not occur, as the animals showed habituation. Retention of habituation was rather short, with most animals recovering from habituation within 10 min. Previous experience of habituation was remembered and animals habituated faster during a second series of experiments with similar repetitive stimuli. About half the number of stimulus trials was necessary to habituate in the second test compared to the first test. This promotion of habituation was observed in animals with delay periods of rest within 60 min following the first habituation. After 90 min of rest from the first habitation, animals showed a similar time course for the second habituation. With five stimuli at 15 min interval during 90 min of the rest, trained animals showed rapid habituation, indicating reinforcement of the memory of previous experiments. Crayfish also showed dishabituation when mechanical stimulation was applied to the tail following habituation. PMID:26853863

  7. A ciliate memorizes the geometry of a swimming arena.

    PubMed

    Kunita, Itsuki; Yamaguchi, Tatsuya; Tero, Atsushi; Akiyama, Masakazu; Kuroda, Shigeru; Nakagaki, Toshiyuki

    2016-05-01

    Previous studies on adaptive behaviour in single-celled organisms have given hints to the origin of their memorizing capacity. Here we report evidence that a protozoan ciliate Tetrahymena has the capacity to learn the shape and size of its swimming space. Cells confined in a small water droplet for a short period were found to recapitulate circular swimming trajectories upon release. The diameter of the circular trajectories and their duration reflected the size of the droplet and the period of confinement. We suggest a possible mechanism for this adaptive behaviour based on a Ca(2+) channel. In our model, repeated collisions with the walls of a confining droplet result in a slow rise in intracellular calcium that leads to a long-term increase in the reversal frequency of the ciliary beat. PMID:27226383

  8. Large-amplitude undulatory swimming near a wall.

    PubMed

    Fernández-Prats, Rafael; Raspa, Veronica; Thiria, Benjamin; Huera-Huarte, Francisco; Godoy-Diana, Ramiro

    2015-01-01

    The propulsive dynamics of a flexible undulating foil in a self-propelled swimming configuration near a wall is studied experimentally. Measurements of the swimming speed and the propulsive force are presented, together with image acquisition of the kinematics of the foil and particle image velocimetry (PIV) in its wake. The presence of the wall enhances the cruising velocity in some cases up to 25% and the thrust by a 45% , for swept angles of 160 and 240°. The physical mechanisms underlying this effect are discussed by studying the vorticity dynamics in the wake of the foil. Proper orthogonal decomposition is applied to the PIV measurements in order to analyse the kinetic energy modal distribution in the flow and to relate it to the propulsion generated by the foil. PMID:25561330

  9. The adaptation of a reflex response to the ongoing phase of locomotion in fish.

    PubMed

    Grillner, S; Rossignol, S; Wallén, P

    1977-10-24

    The reflex response to stimulation of the tail fin has been studied in the swimming fish, by bilateral electromyographical (EMG) recordings in several segments along the body. The response varies with the phase of swimming. When the muscles on one side (segment) are active, a large response will occur on this side but no response on the contralateral side at the same level. When the other side becomes active an identical stimulus will cause an activation of this side but no response on the previously active side. When the movements were filmed a powerful mechanical effect was demonstrated with an augmentation of the ongoing movement, that would result in an instantaneous increase in speed. The stimulus causes in addition a shortening of the duration of the swimming cycle and its components. Most of the results were obtained on spinal dogfish, which also exhibits spontaneous locomotion after a spinal transection. Mainly electrical bipolar stimulation of the tail fin was used. Identical stimuli applied in different phases on an ongoing movement, thus give a reflex response that changes dramatically with the phase of the movement. This phase dependent reflex reversal is functionally meaningful; it is fast and due to spinal mechanisms. PMID:590408

  10. Swimming of bacteria under dielectrophoresis

    NASA Astrophysics Data System (ADS)

    Tran, Ngoc Phu; Marcos, Marcos

    In this work, we present a model to predict the response of a swimming helically flagellated bacterium to a unidirectional dielectrophoretic (DEP) force with its strength varying linearly in space. We employ resistive force theory to compute the hydrodynamic force on the flagellar bundle, and the effects of DEP force and rotational diffusion are examined using the Fokker-Planck equation. The DEP force greatly contributes to the reorientation of the bacterium such that the bacterium's primary axis is aligned with the direction of the force. Interestingly, when the DEP strength varies perpendicularly to the direction of the force, the bacterium's primary axis is no longer aligned with the DEP force, which results in a translation of the bacterium perpendicular to its primary axis. Finally, we show the feasibility to utilize this phenomenon to achieve bacterial focusing. The full name of the second author is MARCOS.

  11. Swimming of a Ciliated Microorganism

    NASA Astrophysics Data System (ADS)

    Guo, Hanliang; Kanso, Eva

    2013-11-01

    We propose a 2D model to consider the locomotion of a ciliated microorganism in a viscous fluid. The model consists of a circular body whose boundary is covered by a finite number of cilia. Stokes paradox does not hold due to the self-propelling nature of the organism. Using a regularized Stokeslet method, we determine numerically the time-dependent swimming motion for prescribed kinematics (undulatory beat) of the individual cilium. Phase differences between neighboring cilia result in metachronal waves characteristic of biological cilia. We compare our results based on the discrete cilia approach with the envelope model proposed by JR Blake. We then study the net locomotion as function of the metachronal wave. We find that, for a given geometry and cilia density, there is an optimal wave number (phase difference) for locomotion in terms of velocity of propulsion and efficiency.

  12. Propulsion of swimming microrobots inspired by metachronal waves in ciliates: from biology to material specifications.

    PubMed

    Palagi, Stefano; Jager, Edwin W H; Mazzolai, Barbara; Beccai, Lucia

    2013-12-01

    The quest for swimming microrobots originates from possible applications in medicine, especially involving navigation in bodily fluids. Swimming microorganisms have become a source of inspiration because their propulsion mechanisms are effective in the low-Reynolds number regime. In this study, we address a propulsion mechanism inspired by metachronal waves, i.e. the spontaneous coordination of cilia leading to the fast swimming of ciliates. We analyse the biological mechanism (referring to its particular embodiment in Paramecium caudatum), and we investigate the contribution of its main features to the swimming performance, through a three-dimensional finite-elements model, in order to develop a simplified, yet effective artificial design. We propose a bioinspired propulsion mechanism for a swimming microrobot based on a continuous cylindrical electroactive surface exhibiting perpendicular wave deformations travelling longitudinally along its main axis. The simplified propulsion mechanism is conceived specifically for microrobots that embed a micro-actuation system capable of executing the bioinspired propulsion (self-propelled microrobots). Among the available electroactive polymers, we select polypyrrole as the possible actuation material and we assess it for this particular embodiment. The results are used to appoint target performance specifications for the development of improved or new electroactive materials to attain metachronal-waves-like propulsion. PMID:24103844

  13. The effects of a sublethal dose of botulinum serotype e on the swimming performance of channel catfish fingerlings.

    PubMed

    Beecham, Rachel; Thomas, Torri; Gao, Dana X; Gaunt, Patricia S

    2014-09-01

    Abstract Visceral toxicosis of catfish (VTC) is a disease of cultured Channel Catfish Ictalurus punctatus in the Mississippi Delta region and surrounding states. The etiology of VTC is associated with botulinum serotype E (BoNT/E), which causes blockage of acetylcholine release at the neuromuscular junction, leading to weakness and paralysis of skeletal muscles (including those involved in swimming). This study attempted to determine if sublethal exposure to purified BoNT/E caused reductions in swimming performance and metabolism of Channel Catfish. Catfish swimming performance was assessed on stocker-sized Channel Catfish (mean weight ± SD, 62.35 ± 2.5 g) with 10 sham-injected fish and 10 fish injected with a sublethal dose of BoNT/E. A modified Blazka-type swim chamber was used to assess swimming performance. We injected Channel Catfish with either 0.015% trypsin or 400 pg purified BoNT/E digested with 0.015% trypsin intracoelomically, then acclimated an individual catfish in the swim chamber for 17 h prior to the swimming trial. Water temperature was maintained at ∼28°C, and dissolved oxygen (DO) was between 4 and 7 mg/L. A critical swimming speed (Ucrit) protocol was followed, and DO and temperature were monitored every 2 min throughout the swim trial. Cost of transport was calculated from the oxygen consumption at each test speed (10-70 cm/s). There was a statistical difference between the Ucrits (P = 0.0034), but no differences were found between the cost of transports (P = 0.67) of the sham-injected and BoNT/E groups. There was a difference in the cost of transport as it relates to the speeds tested (P < 0.0001), cost of transports being highest at low speeds and decreasing as speed increased. These results indicate that botulinum E interferes with the swimming speed of the catfish, which could contribute to the mortality from the disease of VTC and potentially make the fish more susceptible to predation. Received September 20, 2013; accepted

  14. Swimming behavior of selected species of Archaea.

    PubMed

    Herzog, Bastian; Wirth, Reinhard

    2012-03-01

    The swimming behavior of Bacteria has been studied extensively, at least for some species like Escherichia coli. In contrast, almost no data have been published for Archaea on this topic. In a systematic study we asked how the archaeal model organisms Halobacterium salinarum, Methanococcus voltae, Methanococcus maripaludis, Methanocaldococcus jannaschii, Methanocaldococcus villosus, Pyrococcus furiosus, and Sulfolobus acidocaldarius swim and which swimming behavior they exhibit. The two Euryarchaeota M. jannaschii and M. villosus were found to be, by far, the fastest organisms reported up to now, if speed is measured in bodies per second (bps). Their swimming speeds, at close to 400 and 500 bps, are much higher than the speed of the bacterium E. coli or of a very fast animal, like the cheetah, each with a speed of ca. 20 bps. In addition, we observed that two different swimming modes are used by some Archaea. They either swim very rapidly, in a more or less straight line, or they exhibit a slower kind of zigzag swimming behavior if cells are in close proximity to the surface of the glass capillary used for observation. We argue that such a "relocate-and-seek" behavior enables the organisms to stay in their natural habitat. PMID:22247169

  15. Cardiac function in an endothermic fish: cellular mechanisms for overcoming acute thermal challenges during diving.

    PubMed

    Shiels, H A; Galli, G L J; Block, B A

    2015-02-01

    Understanding the physiology of vertebrate thermal tolerance is critical for predicting how animals respond to climate change. Pacific bluefin tuna experience a wide range of ambient sea temperatures and occupy the largest geographical niche of all tunas. Their capacity to endure thermal challenge is due in part to enhanced expression and activity of key proteins involved in cardiac excitation-contraction coupling, which improve cardiomyocyte function and whole animal performance during temperature change. To define the cellular mechanisms that enable bluefin tuna hearts to function during acute temperature change, we investigated the performance of freshly isolated ventricular myocytes using confocal microscopy and electrophysiology. We demonstrate that acute cooling and warming (between 8 and 28°C) modulates the excitability of the cardiomyocyte by altering the action potential (AP) duration and the amplitude and kinetics of the cellular Ca(2+) transient. We then explored the interactions between temperature, adrenergic stimulation and contraction frequency, and show that when these stressors are combined in a physiologically relevant way, they alter AP characteristics to stabilize excitation-contraction coupling across an acute 20°C temperature range. This allows the tuna heart to maintain consistent contraction and relaxation cycles during acute thermal challenges. We hypothesize that this cardiac capacity plays a key role in the bluefin tunas' niche expansion across a broad thermal and geographical range. PMID:25540278

  16. Mechanisms of endoderm formation in a cartilaginous fish reveal ancestral and homoplastic traits in jawed vertebrates

    PubMed Central

    Godard, Benoit G.; Coolen, Marion; Le Panse, Sophie; Gombault, Aurélie; Ferreiro-Galve, Susana; Laguerre, Laurent; Lagadec, Ronan; Wincker, Patrick; Poulain, Julie; Da Silva, Corinne; Kuraku, Shigehiro; Carre, Wilfrid; Boutet, Agnès; Mazan, Sylvie

    2014-01-01

    ABSTRACT In order to gain insight into the impact of yolk increase on endoderm development, we have analyzed the mechanisms of endoderm formation in the catshark S. canicula, a species exhibiting telolecithal eggs and a distinct yolk sac. We show that in this species, endoderm markers are expressed in two distinct tissues, the deep mesenchyme, a mesenchymal population of deep blastomeres lying beneath the epithelial-like superficial layer, already specified at early blastula stages, and the involuting mesendoderm layer, which appears at the blastoderm posterior margin at the onset of gastrulation. Formation of the deep mesenchyme involves cell internalizations from the superficial layer prior to gastrulation, by a movement suggestive of ingressions. These cell movements were observed not only at the posterior margin, where massive internalizations take place prior to the start of involution, but also in the center of the blastoderm, where internalizations of single cells prevail. Like the adjacent involuting mesendoderm, the posterior deep mesenchyme expresses anterior mesendoderm markers under the control of Nodal/activin signaling. Comparisons across vertebrates support the conclusion that endoderm is specified in two distinct temporal phases in the catshark as in all major osteichthyan lineages, in line with an ancient origin of a biphasic mode of endoderm specification in gnathostomes. They also highlight unexpected similarities with amniotes, such as the occurrence of cell ingressions from the superficial layer prior to gastrulation. These similarities may correspond to homoplastic traits fixed separately in amniotes and chondrichthyans and related to the increase in egg yolk mass. PMID:25361580

  17. Cell fusion as the formation mechanism of unreduced gametes in the gynogenetic diploid hybrid fish.

    PubMed

    Wang, Jing; Liu, Qingfeng; Luo, Kaikun; Chen, Xuan; Xiao, Jun; Zhang, Chun; Tao, Min; Zhao, Rurong; Liu, Shaojun

    2016-01-01

    The gynogenetic diploid hybrid clone line (GDH) derived from red crucian carp (♀ RCC) × common carp (♂ CC) possesses the unusual reproductive trait of producing unreduced diploid eggs. To identify the mechanism underlying this phenomenon, we examined the structure, in vivo developmental process and in vitro dynamic development of the GDH gonad. In summary, compared with RCC and CC, GDH showed certain special straits. First, a high frequency (84.7%) of germ cell fusion occurred in gonadal tissue culture in vitro as observed by time-lapse microscopy. Second, microstructural and ultrastructural observation showed numerous binucleated and multinucleated germ cells in the gonad, providing evidence of germ cell fusion in vivo. By contrast, in the diploid RCC and CC ovaries, neither cell fusion nor multinucleated cells were observed during the development of gonads. Third, the ovary of GDH remained at stage I for 10 months, whereas those of RCC and CC remained at that stage for 2 months, indicating that the GDH germ cells underwent abnormal development before meiosis. This report is the first to demonstrate that cell fusion facilitates the formation of unreduced gametes in vertebrates, which is a valuable finding for both evolutionary biology and reproductive biology. PMID:27530321

  18. Cardiac function in an endothermic fish: cellular mechanisms for overcoming acute thermal challenges during diving

    PubMed Central

    Shiels, H. A.; Galli, G. L. J.; Block, B. A.

    2015-01-01

    Understanding the physiology of vertebrate thermal tolerance is critical for predicting how animals respond to climate change. Pacific bluefin tuna experience a wide range of ambient sea temperatures and occupy the largest geographical niche of all tunas. Their capacity to endure thermal challenge is due in part to enhanced expression and activity of key proteins involved in cardiac excitation–contraction coupling, which improve cardiomyocyte function and whole animal performance during temperature change. To define the cellular mechanisms that enable bluefin tuna hearts to function during acute temperature change, we investigated the performance of freshly isolated ventricular myocytes using confocal microscopy and electrophysiology. We demonstrate that acute cooling and warming (between 8 and 28°C) modulates the excitability of the cardiomyocyte by altering the action potential (AP) duration and the amplitude and kinetics of the cellular Ca2+ transient. We then explored the interactions between temperature, adrenergic stimulation and contraction frequency, and show that when these stressors are combined in a physiologically relevant way, they alter AP characteristics to stabilize excitation–contraction coupling across an acute 20°C temperature range. This allows the tuna heart to maintain consistent contraction and relaxation cycles during acute thermal challenges. We hypothesize that this cardiac capacity plays a key role in the bluefin tunas' niche expansion across a broad thermal and geographical range. PMID:25540278

  19. Cell fusion as the formation mechanism of unreduced gametes in the gynogenetic diploid hybrid fish

    PubMed Central

    Wang, Jing; Liu, Qingfeng; Luo, Kaikun; Chen, Xuan; Xiao, Jun; Zhang, Chun; Tao, Min; Zhao, Rurong; Liu, Shaojun

    2016-01-01

    The gynogenetic diploid hybrid clone line (GDH) derived from red crucian carp (♀ RCC) × common carp (♂ CC) possesses the unusual reproductive trait of producing unreduced diploid eggs. To identify the mechanism underlying this phenomenon, we examined the structure, in vivo developmental process and in vitro dynamic development of the GDH gonad. In summary, compared with RCC and CC, GDH showed certain special straits. First, a high frequency (84.7%) of germ cell fusion occurred in gonadal tissue culture in vitro as observed by time-lapse microscopy. Second, microstructural and ultrastructural observation showed numerous binucleated and multinucleated germ cells in the gonad, providing evidence of germ cell fusion in vivo. By contrast, in the diploid RCC and CC ovaries, neither cell fusion nor multinucleated cells were observed during the development of gonads. Third, the ovary of GDH remained at stage I for 10 months, whereas those of RCC and CC remained at that stage for 2 months, indicating that the GDH germ cells underwent abnormal development before meiosis. This report is the first to demonstrate that cell fusion facilitates the formation of unreduced gametes in vertebrates, which is a valuable finding for both evolutionary biology and reproductive biology. PMID:27530321

  20. The deadly swimming of Cercariae: an unusual Stokesian swimmer

    NASA Astrophysics Data System (ADS)

    Prakash, Manu; Krishnamurthy, Deepak

    2014-11-01

    Schistosomiasis, also known as Bilharzia, is a Neglected Tropical Disease (NTD) caused by a parasitic Trematode blood fluke worm. In terms of socio-economic and public health impact, Schistosomiasis is second only to Malaria as the most devastating parasitic disease in tropical countries; with roughly 200 million people infected at any time world-wide and up to 200,000 deaths every year. The infectious form of the parasite, known as Cercariae, emerge from snails into freshwater and infect humans by directly burrowing into the skin. Thus, anyone in contact with infected waters is at risk, which mostly includes children. By establishing a safe experimental means of studying the Cercariae in our lab, we report here their unusual swimming dynamics which include both head-first and tail-first swimming modes. These swimming modes are crucial for the chemotactic activity of Cercariae which allows them to seek out and burrow into human skin. By experimental and analytical means, we demonstrate that Cercariae break symmetry and achieve locomotion at small Reynolds number differently when compared to well-known methods involving traveling waves in the flagellum or chiral beating. Although they utilize the well-known drag anisotropy of a slender body in Stokes flow, the geometry and kinematics of their propulsion mechanism is novel. Based on these results, we propose a new kind of simple Stokesian swimmer (T-joint swimmer) in an attempt to explain the evolutionary advantages of this novel swimming mechanism. Using the above physical insights from a biological and global-health standpoint, we explore ways to hinder the chemotactic capabilities of this parasite.

  1. Swimming Motility Reduces Deposition to Silica Surfaces.

    PubMed

    Lu, Nanxi; Massoudieh, Arash; Liang, Xiaomeng; Hu, Dehong; Kamai, Tamir; Ginn, Timothy R; Zilles, Julie L; Nguyen, Thanh H

    2015-09-01

    The transport and fate of bacteria in porous media is influenced by physicochemical and biological properties. This study investigated the effect of swimming motility on the attachment of cells to silica surfaces through comprehensive analysis of cell deposition in model porous media. Distinct motilities were quantified for different strains using global and cluster-based statistical analyses of microscopic images taken under no-flow condition. The wild-type, flagellated strain DJ showed strong swimming as a result of the actively swimming subpopulation whose average speed was 25.6 μm/s; the impaired swimming of strain DJ77 was attributed to the lower average speed of 17.4 μm/s in its actively swimming subpopulation; and both the nonflagellated JZ52 and chemically treated DJ cells were nonmotile. The approach and deposition of these bacterial cells were analyzed in porous media setups, including single-collector radial stagnation point flow cells (RSPF) and two-dimensional multiple-collector micromodels under well-defined hydrodynamic conditions. In RSPF experiments, both swimming and nonmotile cells moved with the flow when at a distance ≥20 μm above the collector surface. Closer to the surface, DJ cells showed both horizontal and vertical movement, limiting their contact with the surface, while chemically treated DJ cells moved with the flow to reach the surface. These results explain how wild-type swimming reduces attachment. In agreement, the deposition in micromodels was also lowest for DJ compared with those for DJ77 and JZ52. Wild-type swimming specifically reduced deposition on the upstream surfaces of the micromodel collectors. Conducted under environmentally relevant hydrodynamic conditions, the results suggest that swimming motility is an important characteristic for bacterial deposition and transport in the environment. PMID:26436254

  2. Insight on how fishing bats discern prey and adjust their mechanic and sensorial features during the attack sequence

    PubMed Central

    Aizpurua, Ostaizka; Alberdi, Antton; Aihartza, Joxerra; Garin, Inazio

    2015-01-01

    Several insectivorous bats have included fish in their diet, yet little is known about the processes underlying this trophic shift. We performed three field experiments with wild fishing bats to address how they manage to discern fish from insects and adapt their hunting technique to capture fish. We show that bats react only to targets protruding above the water and discern fish from insects based on prey disappearance patterns. Stationary fish trigger short and shallow dips and a terminal echolocation pattern with an important component of the narrowband and low frequency calls. When the fish disappears during the attack process, bats regulate their attack increasing the number of broadband and high frequency calls in the last phase of the echolocation as well as by lengthening and deepening their dips. These adjustments may allow bats to obtain more valuable sensorial information and to perform dips adjusted to the level of uncertainty on the location of the submerged prey. The observed ultrafast regulation may be essential for enabling fishing to become cost-effective in bats, and demonstrates the ability of bats to rapidly modify and synchronise their sensorial and motor features as a response to last minute stimulus variations. PMID:26196094

  3. Insight on how fishing bats discern prey and adjust their mechanic and sensorial features during the attack sequence.

    PubMed

    Aizpurua, Ostaizka; Alberdi, Antton; Aihartza, Joxerra; Garin, Inazio

    2015-01-01

    Several insectivorous bats have included fish in their diet, yet little is known about the processes underlying this trophic shift. We performed three field experiments with wild fishing bats to address how they manage to discern fish from insects and adapt their hunting technique to capture fish. We show that bats react only to targets protruding above the water and discern fish from insects based on prey disappearance patterns. Stationary fish trigger short and shallow dips and a terminal echolocation pattern with an important component of the narrowband and low frequency calls. When the fish disappears during the attack process, bats regulate their attack increasing the number of broadband and high frequency calls in the last phase of the echolocation as well as by lengthening and deepening their dips. These adjustments may allow bats to obtain more valuable sensorial information and to perform dips adjusted to the level of uncertainty on the location of the submerged prey. The observed ultrafast regulation may be essential for enabling fishing to become cost-effective in bats, and demonstrates the ability of bats to rapidly modify and synchronise their sensorial and motor features as a response to last minute stimulus variations. PMID:26196094

  4. Fish oil regulates adiponectin secretion by a peroxisome proliferator-activated receptor-gamma-dependent mechanism in mice.

    PubMed

    Neschen, Susanne; Morino, Katsutaro; Rossbacher, Jörg C; Pongratz, Rebecca L; Cline, Gary W; Sono, Saki; Gillum, Matthew; Shulman, Gerald I

    2006-04-01

    Adiponectin has insulin-sensitizing, antiatherogenic, and anti-inflammatory properties, but little is known about factors that regulate its secretion. To examine the effect of fish oil on adiponectin secretion, mice were fed either a control diet or isocaloric diets containing 27% safflower oil or 27, 13.5, and 8% menhaden fish oil. Within 15 days, fish oil feeding raised plasma adiponectin concentrations two- to threefold in a dose-dependent manner, and the concentrations remained approximately twofold higher for 7 days when the fish oil diet was replaced by the safflower oil diet. Within 24 h, fish oil markedly induced transcription of the adiponectin gene in epididymal adipose tissue but not in subcutaneous fat. The increase of plasma adiponectin by fish oil was completely blocked by administration of the peroxisome proliferator-activated receptor (PPAR)gamma inhibitor bisphenol-A-diglycidyl ether. In contrast, there was no effect of fish oil feeding on adiponectin secretion in PPARalpha-null mice. These data suggest that fish oil is a naturally occurring potent regulator of adiponectin secretion in vivo and that it does so through a PPARgamma-dependent and PPARalpha-independent manner in epididymal fat. PMID:16567512

  5. Airways disorders and the swimming pool.

    PubMed

    Bougault, Valérie; Boulet, Louis-Philippe

    2013-08-01

    Concerns have been expressed about the possible detrimental effects of chlorine derivatives in indoor swimming pool environments. Indeed, a controversy has arisen regarding the possibility that chlorine commonly used worldwide as a disinfectant favors the development of asthma and allergic diseases. The effects of swimming in indoor chlorinated pools on the airways in recreational and elite swimmers are presented. Recent studies on the influence of swimming on airway inflammation and remodeling in competitive swimmers, and the phenotypic characteristics of asthma in this population are reviewed. Preventative measures that could potentially reduce the untoward effects of pool environment on airways of swimmers are discussed. PMID:23830132

  6. A Review of Swimming Cues and Tips for Physical Education

    ERIC Educational Resources Information Center

    Higginson, Kelsey; Barney, David

    2016-01-01

    Swimming is a low-impact activity that causes little stress on joints so it can be done for a lifetime. Many teachers may wish to teach swimming but do not have cues or ideas for doing so. This article reviews swimming cues, relays and equipment that can help a physical education teacher include a swimming unit in their curriculum. Certification…

  7. Swimming performance and metabolism of cultured golden shiners

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The swimming ability and metabolism of golden shiners, Notemigonus crysoleucas, was examined using swim tunnel respirometery. The oxygen consumption and tail beat frequencies at various swimming speeds, an estimation of the standard metabolic rate, and the critical swimming speed (Ucrit) was determ...

  8. Fish Allergy

    MedlinePlus

    ... Story" 5 Things to Know About Zika & Pregnancy Fish Allergy KidsHealth > For Parents > Fish Allergy Print A ... From Home en español Alergia al pescado About Fish Allergy A fish allergy is not exactly the ...

  9. Simulations of Unsteady Aquatic Locomotion: From Unsteadiness in Straight-Line Swimming to Fast-Starts.

    PubMed

    Borazjani, Iman

    2015-10-01

    Unsteady aquatic locomotion is not an exception, but rather how animals often swim. It includes fast-starts (C-start or S-start), escape maneuvers, turns, acceleration/deceleration, and even during steady locomotion the swimming speed fluctuates, i.e., there is unsteadiness. Here, a review of the recent work on unsteady aquatic locomotion with emphasis on numerical simulations is presented. The review is started by an overview of different theoretical and numerical methods that have been used for unsteady swimming, and then the insights provided by these methods on (1) unsteadiness in straight-line swimming and (2) unsteady fast-starts and turns are discussed. The swimming speed's unsteady fluctuations during straight-line swimming are typically less than 3% of the average swimming speed, but recent simulations show that body shape affects fluctuations more than does body kinematics, i.e., changing the shape of the body generates larger fluctuations than does changing its kinematics. For fast-starts, recent simulations show that the best motion to maximize the distance traveled from rest are similar to the experimentally observed C-start maneuvers. Furthermore, another set of simulations, which are validated against measurements of flow in experiments with live fish, investigate the role of fins during the C-start. The simulations showed that most of the force is generated by the body of the fish (not by fins) during the first stage of the C-start when the fish bends itself into the C-shape. However, in the second stage, when it rapidly bends out of the C-shape, more than 70% of the instantaneous hydrodynamic force is produced by the tail. The effect of dorsal and anal fins was less than 5% of the instantaneous force in both stages, except for a short period of time (2 ms) just before the second stage. Therefore, the active control and the erection of the anal/dorsal fins might be related to retaining the stability of the sunfish against roll and pitch during the C

  10. Thermal acclimation, growth, and burst swimming of threespine stickleback: enzymatic correlates and influence of photoperiod.

    PubMed

    Guderley, H; Leroy, P H; Gagné, A

    2001-01-01

    Threespine sticklebacks (Gasterosteus aculeatus) that had been reared in the laboratory under natural photoperiods were acclimated to 23 degrees and 8 degrees C in late spring under increasing day lengths and again in late fall under decreasing day lengths. The parents of these fish were from the anadromous Isle Verte population. In the spring, cold- and warm-acclimated fish grew at the same rates and attained similar condition factors (mass L(-3)), although food intake was considerably higher at 23 degrees C. As both groups had similar increases in mass and condition, the higher axial muscle activities of citrate synthase and phosphofructokinase (measured at 20 degrees C) after cold acclimation were likely a direct response to temperature. Multiple regression analysis showed that axial muscle levels of cytochrome C oxidase and citrate synthase were correlated with the burst swimming speeds of the spring sticklebacks, while growth rates were positively correlated with lactate dehydrogenase levels in pectoral and axial muscles and creatine kinase levels in the axial muscle. In the fall, the fish in both acclimation groups grew little, although they fed at similar rates as in the spring experiment. Overall, the sticklebacks showed lower burst swimming speeds in the fall. In both spring and fall, the burst speeds of cold- and warm-acclimated sticklebacks only differed at warm temperatures. In the spring experiment, the cold-acclimated fish swam faster, whereas in the fall experiment the warm-acclimated fish swam faster despite their lower percentage of axial muscle. Swimming speeds were measured both at a fish's acclimation temperature and after 12 h at the other temperature. Cold-acclimated sticklebacks seem to have more facility in rapidly adjusting to warm temperatures when they have experienced increasing rather than decreasing day lengths, perhaps as a result of the requirements of the spring migration to the intertidal breeding grounds. PMID:11226015

  11. Anguilliform fish propulsion of highest hydrodynamic efficiency

    NASA Astrophysics Data System (ADS)

    Vorus, William S.; Taravella, Brandon M.

    2011-06-01

    It is hypothesized that steady anguilliform swimming motion of aquatic animals is purely reactive such that no net vortex wake is left downstream. This is versus carangiform and tunniform swimming of fish, where vortex streams are shed from tail, fins, and body. But there the animal movements are such to produce partial vortex cancellation downstream in maximizing propulsive efficiency. In anguilliform swimming characteristic of the eel family, it is argued that the swimming motions are configured by the animal such that vortex shedding does not occur at all. However, the propulsive thrust in this case is higher order in the motion amplitude, so that relatively large coils are needed to produce relatively small thrust; the speeds of anguilliform swimmers are less than the carangiform and tunniform, which develop first order thrusts via lifting processes. Results of experimentation on live lamprey are compared to theoretical prediction which assumes the no-wake hypothesis. Two-dimensional analysis is first performed to set the concept. This is followed by three-dimensional analysis using slender-body theory. Slender-body theory has been applied by others in studying anguilliform swimming, as it is ideally suited to the geometry of the lamprey and other eel-like animals. The agreement between this new approach based on the hypothesis of wakeless swimming and the experiments is remarkably good in spite of the physical complexities.

  12. Comparison of fin ray sampling methods on white sturgeon Acipenser transmontanus growth and swimming performance.

    PubMed

    Nguyen, P L; Jackson, Z J; Peterson, D L

    2016-02-01

    Effects of two fin-ray sampling methods on swimming performance, growth and survival were evaluated for hatchery-reared sub-adult white sturgeon Acipenser transmontanus. Fish were subjected to either a notch removal treatment in which a small section was removed from an anterior marginal pectoral-fin ray, or a full removal treatment in which an entire marginal pectoral-fin ray was removed. Control fish did not have fin rays removed, but they were subjected to a sham operation. A modified 3230 l Brett-type swim tunnel was used to evaluate 10 min critical station-holding speeds (SCSH ) of A. transmontanus, immediately after the fin ray biopsies were obtained with each method. Survival and growth were evaluated over a 6 month period for a separate group of fish subjected to the same biopsy methods. Mean ± S.E. 10 min SCSH were 108·0 ± 2·3, 110·0 ± 2·6 and 115·0 ± 3·5 cm s(-1) for the notch removal group, full removal group and control group, respectively, and were not significantly different among treatments. Behavioural characteristics including tail-beat frequency and time spent hunkering were also not significantly different among treatment groups swimming at the same speeds. There were no mortalities and relative growth was similar among treatment groups. Average biopsy time for the notch removal method was lower and the wounds appeared to heal more quickly compared with the full removal method. PMID:26707821

  13. Helicobacter pylori displays spiral trajectories while swimming like a cork-screw in solutions

    NASA Astrophysics Data System (ADS)

    Constantino, Maira A.; Hardcastle, Joseph M.; Bansil, Rama; Jabbarzadeh, Mehdi; Fu, Henry C.

    Helicobacter pylori is a helical shaped bacterium that causes gastritis, ulcers and gastric cancer in humans and other animals. In order to colonize the harsh acidic environment of the stomach H. pylori has evolved a unique biochemical mechanism to go across the viscoelastic gel-like gastric mucus layer. Many studies have been conducted on the swimming of H. pylori in viscous media. However a yet unanswered question is if the helical cell shape influences bacterial swimming dynamics or confers any advantage when swimming in viscous solution. We will present measurements of H. pylori trajectories displaying corkscrew motion while swimming in solution obtained by tracking single cells using 2-dimensional phase contrast imaging at high magnification and fast frame rates and simultaneously imaging their shape. We observe a linear relationship between swimming speed and rotation rate. The experimental trajectories show good agreement with trajectories calculated using a regularized Stokeslet method to model the low Reynolds number swimming behavior. Supported by NSF PHY 1410798 (PI: RB).

  14. Kinematics and energetics of swimming performance during acute warming in brown trout Salmo trutta.

    PubMed

    Lea, J M D; Keen, A N; Nudds, R L; Shiels, H A

    2016-01-01

    This study examined how acute warming of water temperature affects the mechanical efficiency of swimming and aerobic capabilities of the brown trout Salmo trutta. Swimming efficiency was assessed using the relationship between swimming kinematics and forward speed (U), which is thought to converge upon an optimum range of a dimensionless parameter, the Strouhal number (St ). Swim-tunnel intermittent stopped-flow respirometry was used to record kinematics and measure oxygen consumption (ṀO2) of S. trutta during warming and swimming challenges. Salmo trutta maintained St between 0·2 and 0·3 at any given U over a range of temperatures, irrespective of body size. The maintenance of St within the range for maximum efficiency for oscillatory propulsion was achieved through an increase in tail-beat frequency (ftail) and a decrease in tail-beat amplitude (A) as temperature increased. Maintenance of efficient steady-state swimming was fuelled by aerobic metabolism, which increased as temperature increased up to 18° C but declined above this temperature, decreasing the apparent metabolic scope. As St was maintained over the full range of temperatures whilst metabolic scope was not, the results may suggest energetic trade-offs at any given U at temperatures above thermal optima. PMID:26563644

  15. Trapping of swimming microorganisms at lower surfaces by increasing buoyancy.

    PubMed

    Jung, Ilyong; Guevorkian, Karine; Valles, James M

    2014-11-21

    Models suggest that mechanical interactions alone can trap swimming microorganisms at surfaces. Testing them requires a method for varying the mechanical interactions. We tuned contact forces between Paramecia and surfaces in situ by varying their buoyancy with nonuniform magnetic fields. Remarkably, increasing their buoyancy can lead to ∼100% trapping at lower surfaces. A model of Paramecia in surface contact passively responding to external torques quantitatively accounts for the data implying that interactions with a planar surface do not engage their mechanosensing network and illuminating how their trapping differs from other smaller microorganisms. PMID:25479523

  16. The Fish may be Used in the Space System

    NASA Astrophysics Data System (ADS)

    Liu, Chungchu; Liu, Xiaofeng; Lin, Zhongning

    Scientists in Space area like to grow fish in the biosphere, but they worry about that fish will contest oxygen with humans. Therefore growing low-oxygen-needing fish is very important. After research, we found a fish which may be a promising fish used in space system. This fish can grow normally under 1mg O2/1000 mg water oxygen condition while other species of fish die away. How to keep astronauts healthy and having delicious food are problem to raise life qualities of astronauts in space. Our pharmacological test shows that this chosen fish, with high DHA and EPA, in general, other fresh-water fish has low DHA and EPA. It has functions of anti-radiation and anti-tumor. It can also prolong cruor time, anoxia-tolerating, and swimming time after the mice feeding with the fish's meat.

  17. Numerical simulation of a pectoral fin during labriform swimming.

    PubMed

    Shoele, Kourosh; Zhu, Qiang

    2010-06-15

    We numerically examine the fluid-structure interaction and force generation of a skeleton-reinforced fin that geometrically, structurally and kinematically resembles the pectoral fin of a fish during labriform swimming. This fin contains a soft membrane with negligible bending stiffness and 12 embedded rays (modeled as beams). A potential flow-based boundary element model is applied to solve the fluid flow around the fin, in which the vorticity field is modeled as thin vorticity sheets shed from prescribed locations (the sharp trailing edge). The fin motion is actuated by dorsoventral and anteroposterior rotations of the rays (the motion of each ray is controlled individually), as well as pitching motion of the baseline. Consequently, the fin undergoes a combination of flapping (lift-based) and rowing (drag-based) motions typical in labriform swimming. The fin motion contains two strokes: a recovery stroke and a power stroke. The performance of the fin depends upon kinematic parameters such as the Strouhal number, the phase lag between rays, the pitching motion of the baseline and the passive deformations of the rays. The most interesting finding is that the strengthening of the ray at the leading edge plays a pivotal role in performance enhancement by reducing the effective angle of attack and decreasing the power expenditure during the recovery stroke. PMID:20511517

  18. Thin Layer Sensory Cues Affect Antarctic Krill Swimming Kinematics

    NASA Astrophysics Data System (ADS)

    True, A. C.; Webster, D. R.; Weissburg, M. J.; Yen, J.

    2013-11-01

    A Bickley jet (laminar, planar free jet) is employed in a recirculating flume system to replicate thin shear and phytoplankton layers for krill behavioral assays. Planar laser-induced fluorescence (LIF) and particle image velocimetry (PIV) measurements quantify the spatiotemporal structure of the chemical and free shear layers, respectively, ensuring a close match to in situ hydrodynamic and biochemical conditions. Path kinematics from digitized trajectories of free-swimming Euphausia superba examine the effects of hydrodynamic sensory cues (deformation rate) and bloom level phytoplankton patches (~1000 cells/mL, Tetraselamis spp.) on krill behavior (body orientation, swimming modes and kinematics, path fracticality). Krill morphology is finely tuned for receiving and deciphering both hydrodynamic and chemical information that is vital for basic life processes such as schooling behaviors, predator/prey, and mate interactions. Changes in individual krill behavior in response to ecologically-relevant sensory cues have the potential to produce population-scale phenomena with significant ecological implications. Krill are a vital trophic link between primary producers (phytoplankton) and larger animals (seabirds, whales, fish, penguins, seals) as well as the subjects of a valuable commercial fishery in the Southern Ocean; thus quantifying krill behavioral responses to relevant sensory cues is an important step towards accurately modeling Antarctic ecosystems.

  19. Fluid Dynamics of Competitive Swimming: A Computational Study

    NASA Astrophysics Data System (ADS)

    Mittal, Rajat; Loebbeck, Alfred; Singh, Hersh; Mark, Russell; Wei, Timothy

    2004-11-01

    The dolphin kick is an important component in competitive swimming and is used extensively by swimmers immediately following the starting dive as well as after turns. In this stroke, the swimmer swims about three feet under the water surface and the stroke is executed by performing an undulating wave-like motion of the body that is quite similar to the anguilliform propulsion mode in fish. Despite the relatively simple kinematics of this stoke, considerable variability in style and performance is observed even among Olympic level swimmers. Motivated by this, a joint experimental-numerical study has been initiated to examine the fluid-dynamics of this stroke. The current presentation will describe the computational portion of this study. The computations employ a sharp interface immersed boundary method (IBM) which allows us to simulate flows with complex moving boudnaries on stationary Cartesian grids. 3D body scans of male and female Olympic swimmers have been obtained and these are used in conjuction with high speed videos to recreate a realistic dolphin kick for the IBM solver. Preliminary results from these computations will be presented.

  20. On the hydrodynamics of ray-like swimming

    NASA Astrophysics Data System (ADS)

    Bottom, Richard G., II; Borazjani, Iman; Blevins, Erin; Lauder, George V.

    2013-11-01

    There are substantial differences in body shape and motion of stingrays relative to other fish, which drastically affect the hydrodynamics of locomotion. Discovering the flow physics of ray-like locomotion is invaluable not only from a biological standpoint but also for practical application in the development of novel, bio-inspired, man-made vehicles. Here we first develop an analytical model for the stingray's body and fin motion based on experimental laser scan of body shape in the freshwater stingray Potamotrygon orbignyi, and on experimental 3D kinematic data of the wing and body surface obtained from freely-swimming stingrays. The accurate model for the stingray motion is constructed by Fourier analysis of the experimental data resulting in a traveling wave equation with an amplitude coefficient, which is spatially dependent across the fin. Based on this model, we carry out large eddy simulations of the stingray using the immersed boundary method, i.e., the motion of the stingray body is prescribed based on the model, and the motion of the center of mass is calculated. We validate our simulations against experimental data. The simulations reveal the 3D structure of the wake and quantify the swimming performance under different conditions. This work was partly supported by the Center for Computational Research (CCR), University at Buffalo.