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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. A review of fish swimming mechanics and behaviour in altered flows.

    PubMed

    Liao, James C

    2007-11-29

    Fishes suspended in water are subject to the complex nature of three-dimensional flows. Often, these flows are the result of abiotic and biotic sources that alter otherwise uniform flows, which then have the potential to perturb the swimming motions of fishes. The goal of this review is to highlight key studies that have contributed to a mechanistic and behavioural understanding of how perturbing flows affect fish. Most of our understanding of fish behaviour in turbulence comes from observations of natural conditions in the field and laboratory studies employing controlled perturbations, such as vortices generated in the wake behind simple geometric objects. Laboratory studies have employed motion analysis, flow visualization, electromyography, respirometry and sensory deprecation techniques to evaluate the mechanisms and physiological costs of swimming in altered flows. Studies show that flows which display chaotic and wide fluctuations in velocity can repel fishes, while flows that have a component of predictability can attract fishes. The ability to maintain stability in three-dimensional flows, either actively with powered movements or passively using the posture and intrinsic compliance of the body and fins, plays a large role in whether fish seek out or avoid turbulence. Fish in schools or current-swept habitats can benefit from altered flows using two distinct though not mutually exclusive mechanisms: flow refuging (exploiting regions of reduced flow relative to the earth frame of reference) and vortex capture (harnessing the energy of environmental vortices). Integrating how the physical environment affects organismal biomechanics with the more complex issue of behavioural choice requires consideration beyond simple body motions or metabolic costs. A fundamental link between these two ways of thinking about animal behaviour is how organisms sense and process information from the environment, which determines when locomotor behaviour is initiated and

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

    USGS Publications Warehouse

    Castro-Santos, Theodore R.; Farrell, A.P.

    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.

  11. Flow Structures and Efficiency of Swimming Fish school: Numerical Study

    NASA Astrophysics Data System (ADS)

    Yatagai, Yuzuru; Hattori, Yuji

    2013-11-01

    The flow structure and energy-saving mechanism in fish school is numerically investigated by using the volume penalization method. We calculate the various patterns of configuration of fishes and investigate the relation between spatial arrangement and the performance of fish. It is found that the down-stream fish gains a hydrodynamic advantage from the upstream wake shed by the upstream fish. The most efficient configuration is that the downstream fish is placed in the wake. It reduces the drag force of the downstream fish in comparison with that in solo swimming.

  12. 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

  13. 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

  14. 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.

  15. Numerical simulations and vorticity dynamics of self-propelled swimming of 3D bionic fish

    NASA Astrophysics Data System (ADS)

    Xin, ZhiQiang; Wu, ChuiJie

    2012-02-01

    Numerical simulations and the control of self-propelled swimming of three-dimensional bionic fish in a viscous flow and the mechanism of fish swimming are carried out in this study, with a 3D computational fluid dynamics package, which includes the immersed boundary method and the volume of fluid method, the adaptive multi-grid finite volume method, and the control strategy of fish swimming. Firstly, the mechanism of 3D fish swimming was studied and the vorticity dynamics root was traced to the moving body surface by using the boundary vorticity-flux theory. With the change of swimming speed, the contributions of the fish body and caudal fin to thrust are analyzed quantitatively. The relationship between vortex structures of fish swimming and the forces exerted on the fish body are also given in this paper. Finally, the 3D wake structure of self-propelled swimming of 3D bionic fish is presented. The in-depth analysis of the 3D vortex structure in the role of 3D biomimetic fish swimming is also performed.

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. Three-dimensional spatial representation in freely swimming fish.

    PubMed

    Burt de Perera, Theresa; Holbrook, Robert I

    2012-08-01

    Research on spatial cognition has focused on how animals encode the horizontal component of space. However, most animals travel vertically within their environments, particularly those that fly or swim. Pelagic fish move with six degrees of freedom and must integrate these components to navigate accurately--how do they do this? Using an assay based on associative learning of the vertical and horizontal components of space within a rotating Y-maze, we found that fish (Astyanax fasciatus) learned and remembered information from both horizontal and vertical axes when they were presented either separately or as an integrated three-dimensional unit. When information from the two components conflicted, the fish used the previously learned vertical information in preference to the horizontal. This not only demonstrates that the horizontal and vertical components are stored separately in the fishes' representation of space (simplifying the problem of 3D navigation), but also suggests that the vertical axis contains particularly salient spatial cues--presumably including hydrostatic pressure. To explore this latter possibility, we developed a physical theoretical model that shows how fish could determine their absolute depth using pressure. We next considered full volumetric spatial cognition. Astyanax were trained to swim towards a reward in a Y-maze that could be rotated, before the arms were removed during probe trials. The subjects were tracked in three dimensions as they swam freely through the surrounding cubic tank. The results revealed that fish are able to accurately encode metric information in a volume, and that the error accrued in the horizontal and vertical axes whilst swimming in probe trials was similar. Together, these experiments demonstrate that unlike in surface-bound rats, the vertical component of the representation of space is vitally important to fishes. We hypothesise that the representation of space in the brain of vertebrates could ultimately be

  12. 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.

  13. New insights into fish swimming: a proteomic and isotopic approach in gilthead sea bream.

    PubMed

    Martin-Perez, Miguel; Fernandez-Borras, Jaume; Ibarz, Antoni; Millan-Cubillo, Antonio; Felip, Olga; de Oliveira, Eliandre; Blasco, Josefina

    2012-07-01

    Moderate exercise enhances fish growth, although underlying physiological mechanisms are not fully known. Here we performed a proteomic and metabolic study in white (WM) and red (RM) muscle of gilthead sea bream juveniles swimming at 1.5 body lengths per second. Continuous swimming for four weeks enhanced fish growth without increasing food intake. Exercise affected muscle energy stores by decreasing lipid and glycogen contents in WM and RM, respectively. Protein synthesis capacity (RNA/protein), energy use (estimated by lipid-δ(13)C and glycogen-δ(13)C), and enzymatic aerobic capacity increased in WM, while protein turnover (expressed by δ(15)N-fractionation) did not change. RM showed no changes in any of these parameters. 2D-PAGE analysis showed that almost 15% of sarcoplasmic protein spots from WM and RM differed in response to exercise, most being over-expressed in WM and under-expressed in RM. Protein identification by MALDI-TOF/TOF-MS and LC-MS/MS revealed exercise-induced enhancement of several pathways in WM (carbohydrate catabolism, protein synthesis, muscle contraction, and detoxification) and under-expression of others in RM (energy production, muscle contraction, and homeostatic processes). The mechanism underpinning the phenotypic response to exercise sheds light on the adaptive processes of fish muscles, being the sustained-moderate swimming induced in gilthead sea bream achieved mainly by WM, thus reducing the work load of RM and improving swimming performance and food conversion efficiency.

  14. 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.

  15. Optimum swimming pathways of fish spawning migrations in rivers.

    PubMed

    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 10(5) 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. PMID:22486084

  16. 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.

  17. THE SECRETION OF INERT GAS INTO THE SWIM-BLADDER OF FISH

    PubMed Central

    Wittenberg, Jonathan B.

    1958-01-01

    The composition of the gas mixture secreted into the swim-bladders of several species of fish has been determined in the mass spectrometer. The secreted gas differed greatly from the gas mixture breathed by the fish in the relative proportions of the chemically inert gases, argon, neon, helium, and nitrogen. Relative to nitrogen the proportion of the very soluble argon was increased and the proportions of the much less soluble neon and helium decreased. The composition of the secreted gas approaches the composition of the gas mixture dissolved in the tissue fluid. A theory of inert gas secretion is proposed. It is suggested that oxygen gas is actively secreted and evolved in the form of minute bubbles, that inert gases diffuse into these bubbles, and that the bubbles are passed into the swim-bladder carrying with them inert gases. Coupled to a preferential reabsorption of oxygen from the swim-bladder this mechanism can achieve high tensions of inert gas in the swim-bladder. The accumulation of nearly pure nitrogen in the swim-bladder of goldfish (Carassius auratus) is accomplished by the secretion of an oxygen-rich gas mixture followed by the reabsorption of oxygen. PMID:13514011

  18. 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

  19. 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

  20. Hydrodynamics of burst swimming fish larvae; a conceptual model approach.

    PubMed

    Verhagen, Jan H G

    2004-07-21

    Burst swimming of fish larvae is analysed from a hydrodynamic point of view. A picture of the expected flow pattern is presented based on information in literature on unsteady-flow patterns around obstacles in the intermediate Reynolds number region. It is shown that the acceleration stage of burst swimming under restricted conditions can be treated as a frictionless impulsive motion. The stream pattern resulting from this motion is presented and the efficiency of locomotion during the acceleration stage is calculated. The flow pattern in the post-acceleration stage is sketched and the origin of an interaction between the viscous and the reactive force contribution to the propulsive force in this stage is discussed. It is explained how this interaction can lead to an increase in propulsive efficiency. A conceptual model is developed describing the three stages in burst swimming locomotion: the acceleration stage, the post-acceleration stage and the gliding stage. Data from literature of the travel distance versus time relation of the common carp larva (Cyprinus carpio) of 5.5-mm length has been used to test the model results. The test appeared remarkably successful, and the model results for larger larvae up to 22 mm length are presented. The gliding distance as a function of larval length resulting from the model has been compared with experimental data from literature. PMID:15207478

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

    PubMed

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

    2015-01-01

    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.

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

    PubMed

    Castro-Santos, Theodore

    2005-02-01

    Migrating fish traversing velocity barriers are often forced to swim at speeds greater than their maximum sustained speed (U(ms)). 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.

  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. 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.

  7. 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

  8. 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.

  9. Assessing possible effects of fish-culture systems on fish swimming: the role of stability in turbulent flows.

    PubMed

    Webb, Paul W; Cotel, Aline J

    2011-06-01

    Fish are cultured in ponds, recirculating systems, raceways, and cages. Turbulence is associated with one or more of mechanisms to facilitate food accessibility, maintain adequate levels of oxygen, remove carbon dioxide, urinary and fecal wastes, as well as from locomotion of fishes themselves. Turbulence has been shown to have positive and negative effects on fish swimming, feeding, and energetics, usually with negative impacts at very low and at high levels, and least effects and sometimes positive effects at intermediate levels. Differences in responses of fishes with varying levels of turbulence are related to the size of eddies relative to the size of a fish (larvae, juveniles, and adults). Impacts on locomotor functions are associated with eddy diameters of the order of 0.5-1L, where L is the total length of a fish. Negative locomotor impacts of turbulence are associated with eddies challenging stability, while positive effects promote drafting and station holding with reduced locomotor motions. Deployment of control surfaces increases with the level of turbulence up to a threshold where control is overwhelmed. The design of culture facilities is expected to affect levels of turbulence and may be engineered to provide optimal levels facilitating high growth.

  10. 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.

  11. 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.

  12. The mechanical efficiency of front crawl swimming.

    PubMed

    Toussaint, H M; Knops, W; De Groot, G; Hollander, A P

    1990-06-01

    In this study the gross efficiency of swimming was determined in a group of male (N = 6) and female (N = 4) competitive swimmers. The gross efficiency is defined as the ratio of the power output (W) to the power input (W). In a range of swimming velocities (0.95-1.6 m.s-1), the power input (rate of energy expenditure, 445-1137 W) was calculated from the oxygen uptake values (1.33-3.25 1 O2.min-1). The total power output (26-108 W) was directly measured during front crawl swimming using a system of underwater push-off pads instrumented with a force transducer (MAD-system). Using the MAD-system, the effect on total body drag due to the addition of the respiratory apparatus was evaluated to be negligible. The gross efficiency ranged from 5 to 9.5%. At equal swimming speed, the male competitive swimmers demonstrated a higher gross efficiency. However, this was due to the higher power output required by the male swimmers at a given speed. Gross efficiency was dependent on the absolute power output such that as power output increased so did the calculated gross efficiency. At the same power output, the values for the gross efficiency do not differ between the male and female competitive swimmers. PMID:2381310

  13. 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.

  14. 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.

  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. 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

  17. 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.

  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. 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.

  20. Ontogeny of critical and prolonged swimming performance for the larvae of six Australian freshwater fish species.

    PubMed

    Kopf, S M; Humphries, P; Watts, R J

    2014-06-01

    Critical (<30 min) and prolonged (>60 min) swimming speeds in laboratory chambers were determined for larvae of six species of Australian freshwater fishes: trout cod Maccullochella macquariensis, Murray cod Maccullochella peelii, golden perch Macquaria ambigua, silver perch Bidyanus bidyanus, carp gudgeon Hypseleotris spp. and Murray River rainbowfish Melanotaenia fluviatilis. Developmental stage (preflexion, flexion, postflexion and metalarva) better explained swimming ability than did length, size or age (days after hatch). Critical speed increased with larval development, and metalarvae were the fastest swimmers for all species. Maccullochella macquariensis larvae had the highest critical [maximum absolute 46.4 cm s(-1) and 44.6 relative body lengths (L(B)) s(-1)] and prolonged (maximum 15.4 cm s(-1), 15.6 L(B) s(-1)) swimming speeds and B. bidyanus larvae the lowest critical (minimum 0.1 cm s(-1), 0.3 L(B) s(-1)) and prolonged swimming speeds (minimum 1.1 cm s(-1), 1.0 L(B) s(-1)). Prolonged swimming trials determined that the larvae of some species could not swim for 60 min at any speed, whereas the larvae of the best swimming species, M. macquariensis, could swim for 60 min at 44% of the critical speed. The swimming performance of species with precocial life-history strategies, with well-developed larvae at hatch, was comparatively better and potentially had greater ability to influence their dispersal by actively swimming than species with altricial life-history strategies, with poorly developed larvae at hatch.

  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. 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.

  3. 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

  4. Mechanics of undulatory swimming in a frictional fluid.

    PubMed

    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.

  5. 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.

  6. Parasite-induced and parasite development-dependent alteration of the swimming behavior of fish hosts.

    PubMed

    Santos, E G N; Santos, C Portes

    2013-07-01

    Parasites with complex life cycles have the ability to change the behavior of their intermediate host in a way that increases their transmission rate to the next host. However, the level of behavioral changes can vary considerably, depending on the stage of parasite development and parasite intensity. To investigate the influence of such parameters, we evaluated the locomotory activity of the fish Poecilia vivipara prior to experimental infections, 7 days post-infection (dpi) and 14dpi with cercariae of the digenean Ascocotyle (Phagicola) pindoramensis. The locomotory activity was monitored using an image system, Videomex(®), linked to with a video camera able to record the swimming behavior of the fishes. At the end of the experiments, fishes were dissected and all metacercariae from the gills and mesenteries, the specific sites utilized by A. (P.) pindoramensis, were recovered and counted. There was a significant decrease in the swimming behavior of fishes after 14dpi. Similarly, we found a significant correlation between the swimming behavior of the fishes and parasite intensity in both sites of infection. It is surmised that the decrease in locomotory activity of P. vivipara caused by A. (P.) pindoramensis can disturb its predator-prey relationship in natural environment.

  7. 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.

  8. 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.

  9. 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

  10. 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).

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. Neural mechanism of optimal limb coordination in crustacean swimming

    PubMed Central

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

    2014-01-01

    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

  18. The physiology and mechanics of undulatory swimming: a student laboratory exercise using medicinal leeches.

    PubMed

    Ellerby, David J

    2009-09-01

    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 mechanics, hydrostatic skeletons, and the physiological features that allow leeches to deal with the volume increase and osmotic load imposed by the meal. Analyses can be carried out at a range of levels tailored to suit a particular class.

  19. 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.

  20. 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.

  1. 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

  2. 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

  3. 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.

  4. Evaluation of a new coded electromyogram transmitter for studying swimming behavior and energetics in free-ranging fish

    SciTech Connect

    Brown, Richard S.; Tatara, Chris P.; Stephenson, John R.; Berejikian, Barry A.

    2007-06-25

    A new coded electromyogram (CEMG) transmitter was recently introduced to the market to allow broader application and greater flexibility of configurations. CEMG transmitters were implanted into twenty steelhead (Oncorhynchus mykiss) and calibrated to swimming speed in a respirometer. Linear regression models showed a strong positive relationship between output from CEMG transmitters and swimming speed. However, when signals from multiple transmitters were grouped, the relationship between CEMG output and swimming speed was less accurate than if signals from individual transmitters were used. The results, therefore, do not suggest that the CEMG transmitters acted similarly in all fish. Calibration data from one transmitter was not readily transferable among multiple fish implanted with the same transmitter, suggesting that the same transmitter implanted in multiple fish also performed dissimilarly. Variation in fish length, fish weight, location of transmitter implantation (distance from snout), and distance between the electrode tips did not account for the variation in models. Transmitters also had a relatively small working range of output at the swimming speeds tested. Nevertheless, new CEMG transmitters appear to have improved capabilities and should allow researchers to examine the locomotory behavior and energetics of smaller fish than previously possible with greater ease and less expense.

  5. Use of the swim bladder and lateral line in near-field sound source localization by fish.

    PubMed

    Coffin, Allison B; Zeddies, David G; Fay, Richard R; Brown, Andrew D; Alderks, Peter W; Bhandiwad, Ashwin A; Mohr, Robert A; Gray, Michael D; Rogers, Peter H; Sisneros, Joseph A

    2014-06-15

    We investigated the roles of the swim bladder and the lateral line system in sound localization behavior by the plainfin midshipman fish (Porichthys notatus). Reproductive female midshipman underwent either surgical deflation of the swim bladder or cryoablation of the lateral line and were then tested in a monopolar sound source localization task. Fish with nominally 'deflated' swim bladders performed similar to sham-deflated controls; however, post-experiment evaluation of swim bladder deflation revealed that a majority of 'deflated' fish (88%, seven of the eight fish) that exhibited positive phonotaxis had partially inflated swim bladders. In total, 95% (21/22) of fish that localized the source had at least partially inflated swim bladders, indicating that pressure reception is likely required for sound source localization. In lateral line experiments, no difference was observed in the proportion of females exhibiting positive phonotaxis with ablated (37%) versus sham-ablated (47%) lateral line systems. These data suggest that the lateral line system is likely not required for sound source localization, although this system may be important for fine-tuning the approach to the sound source. We found that midshipman can solve the 180 deg ambiguity of source direction in the shallow water of our test tank, which is similar to their nesting environment. We also found that the potential directional cues (phase relationship between pressure and particle motion) in shallow water differs from a theoretical free-field. Therefore, the general question of how fish use acoustic pressure cues to solve the 180 deg ambiguity of source direction from the particle motion vector remains unresolved.

  6. Long-term behavioral tracking of freely swimming weakly electric fish.

    PubMed

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

    2014-03-06

    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.

  7. 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

  8. 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.

  9. Effects of longitudinal body position and swimming speed on mechanical power of deep red muscle from skipjack tuna (Katsuwonus pelamis).

    PubMed

    Syme, Douglas A; Shadwick, Robert E

    2002-01-01

    The mechanical power output of deep, red muscle from skipjack tuna (Katsuwonus pelamis) was studied to investigate (i) whether this muscle generates maximum power during cruise swimming, (ii) how the differences in strain experienced by red muscle at different axial body locations affect its performance and (iii) how swimming speed affects muscle work and power output. Red muscle was isolated from approximately mid-way through the deep wedge that lies next to the backbone; anterior (0.44 fork lengths, ANT) and posterior (0.70 fork lengths, POST) samples were studied. Work and power were measured at 25 degrees C using the work loop technique. Stimulus phases and durations and muscle strains (+/- 5.5 % in ANT and +/- 8 % in POST locations) experienced during cruise swimming at different speeds were obtained from previous studies and used during work loop recordings. In addition, stimulus conditions that maximized work were determined. The stimulus durations and phases yielding maximum work decreased with increasing cycle frequency (analogous to tail-beat frequency), were the same at both axial locations and were almost identical to those used by the fish during swimming, indicating that the muscle produces near-maximal work under most conditions in swimming fish. While muscle in the posterior region undergoes larger strain and thus produces more mass-specific power than muscle in the anterior region, when the longitudinal distribution of red muscle mass is considered, the anterior muscles appear to contribute approximately 40% more total power. Mechanical work per length cycle was maximal at a cycle frequency of 2-3 Hz, dropping to near zero at 15 Hz and by 20-50% at 1 Hz. Mechanical power was maximal at a cycle frequency of 5 Hz, dropping to near zero at 15 Hz. These fish typically cruise with tail-beat frequencies of 2.8-5.2 Hz, frequencies at which power from cyclic contractions of deep red muscles was 75-100% maximal. At any given frequency over this range, power

  10. 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

  11. Deep RNA Sequencing of the Skeletal Muscle Transcriptome in Swimming Fish

    PubMed Central

    Palstra, Arjan P.; Beltran, Sergi; Burgerhout, Erik; Brittijn, Sebastiaan A.; Magnoni, Leonardo J.; Henkel, Christiaan V.; Jansen, Hans J.; van den Thillart, Guido E. E. J. M.; Spaink, Herman P.; Planas, Josep V.

    2013-01-01

    Deep RNA sequencing (RNA-seq) was performed to provide an in-depth view of the transcriptome of red and white skeletal muscle of exercised and non-exercised rainbow trout (Oncorhynchus mykiss) with the specific objective to identify expressed genes and quantify the transcriptomic effects of swimming-induced exercise. Pubertal autumn-spawning seawater-raised female rainbow trout were rested (n = 10) or swum (n = 10) for 1176 km at 0.75 body-lengths per second in a 6,000-L swim-flume under reproductive conditions for 40 days. Red and white muscle RNA of exercised and non-exercised fish (4 lanes) was sequenced and resulted in 15–17 million reads per lane that, after de novo assembly, yielded 149,159 red and 118,572 white muscle contigs. Most contigs were annotated using an iterative homology search strategy against salmonid ESTs, the zebrafish Danio rerio genome and general Metazoan genes. When selecting for large contigs (>500 nucleotides), a number of novel rainbow trout gene sequences were identified in this study: 1,085 and 1,228 novel gene sequences for red and white muscle, respectively, which included a number of important molecules for skeletal muscle function. Transcriptomic analysis revealed that sustained swimming increased transcriptional activity in skeletal muscle and specifically an up-regulation of genes involved in muscle growth and developmental processes in white muscle. The unique collection of transcripts will contribute to our understanding of red and white muscle physiology, specifically during the long-term reproductive migration of salmonids. PMID:23308156

  12. 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.

  13. 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

  14. 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

  15. 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

  16. 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.

  17. Modelling the mechanics and hydrodynamics of swimming E. coli.

    PubMed

    Hu, Jinglei; Yang, Mingcheng; Gompper, Gerhard; Winkler, Roland G

    2015-10-28

    The swimming properties of an E. coli-type model bacterium are investigated by mesoscale hydrodynamic simulations, combining molecular dynamics simulations of the bacterium with the multiparticle particle collision dynamics method for the embedding fluid. The bacterium is composed of a spherocylindrical body with attached helical flagella, built up from discrete particles for an efficient coupling with the fluid. We measure the hydrodynamic friction coefficients of the bacterium and find quantitative agreement with experimental results of swimming E. coli. The flow field of the bacterium shows a force-dipole-like pattern in the swimming plane and two vortices perpendicular to its swimming direction arising from counterrotation of the cell body and the flagella. By comparison with the flow field of a force dipole and rotlet dipole, we extract the force-dipole and rotlet-dipole strengths for the bacterium and find that counterrotation of the cell body and the flagella is essential for describing the near-field hydrodynamics of the bacterium.

  18. Novel method based on video tracking system for simultaneous measurement of kinematics and flow in the wake of a freely swimming fish

    NASA Astrophysics Data System (ADS)

    Wu, Guanhao; Yang, Yan; Zeng, Lijiang

    2006-11-01

    A novel method based on video tracking system for simultaneous measurement of kinematics and flow in the wake of a freely swimming fish is described. Spontaneous and continuous swimming behaviors of a variegated carp (Cyprinus carpio) are recorded by two cameras mounted on a translation stage which is controlled to track the fish. By processing the images recorded during tracking, the detailed kinematics based on calculated midlines and quantitative analysis of the flow in the wake during a low-speed turn and burst-and-coast swimming are revealed. We also draw the trajectory of the fish during a continuous swimming bout containing several moderate maneuvers. The results prove that our method is effective for studying maneuvers of fish both from kinematic and hydrodynamic viewpoints.

  19. 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

  20. Fluid mechanics of swimming bacteria with multiple flagella.

    PubMed

    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. PMID:24827275

  1. 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.

  2. Fluid mechanics of swimming bacteria with multiple flagella.

    PubMed

    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.

  3. 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.

  4. 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

  5. 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

  6. 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.

  7. 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

  8. 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

  9. 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.

  10. 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

  11. Mechanisms underlying rhythmic locomotion: body-fluid interaction in undulatory swimming.

    PubMed

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

    2011-02-15

    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.

  12. 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

  13. 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.

  14. 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.

  15. Beyond U(crit): matching swimming performance tests to the physiological ecology of the animal, including a new fish 'drag strip'.

    PubMed

    Nelson, J A; Gotwalt, P S; Reidy, S P; Webber, D M

    2002-10-01

    Locomotor performance of animals is of considerable interest from management, physiological, ecological and evolutionary perspectives. Yet, despite the extensive commercial exploitation of fishes and interest in the health of various fish stocks, the relationships between performance capacity, natural selection, ecology and physiology are poorly known for fishes. One reason may be the technical challenges faced when trying to measure various locomotor capacities in aquatic species, but we will argue that the slow pace of developing new species-appropriate swim tests is also hindering progress. A technique developed for anadromous salmonids (the U(crit) procedure) has dominated the fish exercise physiology field and, while accounting for major advances in the field, has often been used arbitrarily. Here we propose criteria swimming tests should adhere to and report on several attempts to match swimming tests to the physiological ecology of the animal. Sprint performance measured with a laser diode/photocell timed 'drag strip' is a new method employing new technology and is reported on in some detail. A second new test involves accelerating water past the fish at a constant rate in a traditional swim tunnel/respirometer. These two performance tests were designed to better understand the biology of a bentho-pelagic marine fish, the Atlantic cod (Gadus morhua). Finally, we report on a modified incremental velocity test that was developed to better understand the biology of the blacknose dace (Rhinichthys atratulus), a Nearctic, lotic cyprinid.

  16. 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.

  17. Fins improve the swimming performance of fish sperm: a hydrodynamic analysis of the Siberian sturgeon Acipenser baerii.

    PubMed

    Gillies, Eric A; Bondarenko, Volodymyr; Cosson, Jacky; Pacey, Allan A

    2013-02-01

    The flagella of sturgeon sperm have an ultrastructure comprising paddle-like fins extending along most of their length. These fins are seen in several other marine and freshwater fish. The sperm of these fish are fast swimmers and are relatively short lived: it is therefore tempting to think of these fins as having evolved for hydrodynamic advantage, but the actual advantage they impart, at such a small length scale and slow speed, is unclear. The phrase "the fins improve hydrodynamic efficiency" is commonly found in biological literature, yet little hydrodynamic analysis has previously been used to support such conjectures. In this paper, we examine various hydrodynamic models of sturgeon sperm and investigate both swimming velocity and energy expenditure. All of the models indicate a modest hydrodynamic advantage of finned sperm, in both straight line swimming speed and a hydrodynamic efficiency measure. We find a hydrodynamic advantage for a flagellum with fins, over one without fins, of the order of 15-20% in straight line propulsive velocity and 10-15% in a hydrodynamic efficiency measure. PMID:23233331

  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. 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…

  20. 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.

  1. 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.

  2. Environmental effects on fish immune mechanisms.

    PubMed

    Bly, J E; Quiniou, S M; Clem, L W

    1997-01-01

    Environmental stress factors which influence fish immune (and likely many other physiological) functions can be divided into two broad, but not mutually exclusive, categories, namely those which occur naturally and those which are artificial. Natural environmental stress factors include season, temperature, salinity and photoperiod as well as social stress factors such as crowding and hierarchy. In general, artificial environmental stress factors are man made, and mainly involve pollutants such as acid rain, heavy metals and organic compounds. The available data indicate that regardless of which immune parameters are assessed, both natural and artificial environmental stress factors appear to suppress immune functions. Of the numerous environmental stress factors considered, pollutants, handling/confinement and low temperature are probably the best studied forms in fish. All three forms of stress factors have been shown to suppress components of both the innate (non-specific) and adaptive arms of the immune system. Since immune responses which protect against invading pathogens frequently involve interactions between both the innate and adaptive arms of the immune system, it seems reasonable to conclude that either acute or chronic exposure to stress factors may predispose fish to infectious diseases. Signalling mechanisms responsible for the effects of these various stress factors on immunity in fish are poorly understood, although elevated serum ACTH and cortisol levels appear to be involved in some cases. A better understanding of the mechanism(s) resulting in immunosuppression should facilitate future in vivo manipulations to reduce susceptibility to disease in aquaculture situations.

  3. Establishment of gel materials with different mechanical properties by 3D gel printer SWIM-ER

    NASA Astrophysics Data System (ADS)

    Ota, Takafumi; Tase, Taishi; Okada, Koji; Saito, Azusa; Takamatsu, Kyuuichiro; Kawakami, Masaru; Furukawa, Hidemitsu

    2016-04-01

    A 3D printer is a device which can directly produce objects whose shape is the same as the original 3D digital data. Hydrogels have unique properties such as high water content, low frictional properties, biocompatibility, material permeability and high transparency, which are rare in hard and dry materials. These superior characteristics of gels promise useful medical applications. We have been working on the development of a 3D gel printer, SWIM-ER (Soft and Wet Industrial - Easy Realizer), which can make models of organs and artificial blood vessels with gel material. However, 3D printing has a problem: the mechanical properties of the printed object vary depending on printing conditions, and this matter was investigated with SWIM-ER. In the past, we found that mechanical properties of 3D gel objects depend on the deposition orientation in SWIM-ER. In this study, gels were printed with different laser scanning speeds. The mechanical properties of these gels were investigated by compression tests, water content measurements and SMILS (Scanning Microscopic Light Scattering).

  4. 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.

  5. 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

  6. 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

  7. 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.

  8. Pharmacological mechanisms of antidepressant-like effect of tipepidine in the forced swimming test.

    PubMed

    Kawaura, Kazuaki; Miki, Risa; Urashima, Yuri; Kawahara, Ryo; Soeda, Fumio; Shirasaki, Tetsuya; Takahama, Kazuo

    2012-01-15

    We previously reported that the centrally acting non-narcotic antitussive, tipepidine, produces a novel antidepressant-like effect in the forced swimming test in rats, but the mechanism of the antidepressant-like effect of tipepidine is not clear. We investigated the pharmacological mechanism of the antidepressant-like effect of tipepidine in the forced swimming test in rats. A catecholamine-depleting agent, alpha-methyl-p-tyrosine (AMPT; 300 mg/kg, s.c.), was given 6h before the first injection and with the last injection of tipepidine (40 mg/kg, i.p.). A serotonin (5-HT)-depleting agent, p-chlorophenylalanine (PCPA; 350 mg/kg, i.p.), was given 72 h and 48 h before the pretest session. The dopamine D(1) receptor antagonist, SCH23390 (0.02 mg/kg, s.c.) was given 15min before each of the three injections of tipepidine. The dopamine D(2) receptor antagonist raclopride (0.2mg/kg, s.c.), the alpha 1 adrenoceptor antagonist prazosin (1mg/kg, i.p.), the alpha 2 adrenoceptor antagonist yohimbine (2mg/kg, i.p.) and the beta adrenoceptor antagonist propranolol (2mg/kg, i.p.) were given 30 min before each of the three injections of tipepidine. AMPT, but not PCPA, significantly inhibited the immobility time-reducing effect of tipepidine in the forced swimming test. Furthermore, the effect of tipepidine was significantly inhibited by SCH23390 and yohimbine. However, raclopride, prazosin, and propranolol failed to block the effect of tipepidine. The results suggest that the antidepressant-like effect of tipepidine in the forced swimming test may be due at least in part to the effects of dopamine and noradrenaline released at the dopamine D(1) receptor and alpha 2 adrenoceptor, respectively.

  9. 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

  10. 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.

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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

  16. Mechanical versus physiological determinants of swimming speeds in diving Brünnich's guillemots.

    PubMed

    Lovvorn, J R; Croll, D A; Liggins, G A

    1999-07-01

    For fast flapping flight of birds in air, the maximum power and efficiency of the muscles occur over a limited range of contraction speeds and loads. Thus, contraction frequency and work per stroke tend to stay constant for a given species. In birds such as auks (Alcidae) that fly both in air and under water, wingbeat frequencies in water are far lower than in air, and it is unclear to what extent contraction frequency and work per stroke are conserved. During descent, compression of air spaces dramatically lowers buoyant resistance, so that maintaining a constant contraction frequency and work per stroke should result in an increased swimming speed. However, increasing speed causes exponential increases in drag, thereby reducing mechanical versus muscle efficiency. To investigate these competing factors, we have developed a biomechanical model of diving by guillemots (Uria spp.). The model predicted swimming speeds if stroke rate and work per stroke stay constant despite changing buoyancy. We compared predicted speeds with those of a free-ranging Brünnich's guillemot (U. lomvia) fitted with a time/depth recorder. For descent, the model predicted that speed should gradually increase to an asymptote of 1.5-1.6 m s-1 at approximately 40 m depth. In contrast, the instrumented guillemot typically reached 1.5 m s-1 within 10 m of the water surface and maintained that speed throughout descent to 80 m. During ascent, the model predicted that guillemots should stroke steadily at 1.8 m s-1 below their depth of neutral buoyancy (62 m), should alternate stroking and gliding at low buoyancies from 62 to 15 m, and should ascend passively by buoyancy alone above 15 m depth. However, the instrumented guillemot typically ascended at 1.25 m s-1 when negatively buoyant, at approximately 1.5 m s-1 from 62 m to 25 m, and supplemented buoyancy with stroking above 25 m. Throughout direct descent, and during ascent at negative and low positive buoyancies (82-25 m), the guillemot

  17. Computational and mathematical modeling of the effects of tailbeat frequency and flexural stiffness in swimming fish.

    PubMed

    Root, Robert G; Liew, C W

    2014-02-01

    In this paper we describe how we combine computational and mathematical models to form virtual fish to explore different hypotheses about the impact of centra. We show how we create simulation models using a combination of a mathematical model of a fish-like robot using caudal fin propulsion, a propulsion model, and an optimizer, to explore the impact of centra under various scenarios. The optimizer uses the mathematical model to construct valid configurations of the digital robot and uses the utility function and propulsion model to evaluate the performance of each configuration. The evaluations are used to explore the adaptive landscape and find high-performing configurations. Our results show that the high-performing configurations have both increased (flexural) stiffness of the tail and higher tailbeat frequencies. PMID:24439761

  18. 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.

  19. Myosin heavy chain and parvalbumin expression in swimming and feeding muscles of centrarchid fishes: the molecular basis of the scaling of contractile properties.

    PubMed

    Campion, L A; Choi, S; Mistry, H L; Coughlin, D J

    2012-10-01

    In centrarchid fishes, such as bluegill (Lepomis macrochirus, Rafinesque) and largemouth bass (Micropterus salmoides, Lacepède), the contractile properties of feeding and swimming muscles show different scaling patterns. While the maximum shortening velocity (V(max)) and rate of relaxation from tetanus of swimming or myotomal muscle slow with growth, the feeding muscle shows distinctive scaling patterns. Cranial epaxial muscle, which is used to elevate the head during feeding strikes, retains fast contractile properties across a range of fish sizes in both species. In bass, the sternohyoideous muscle, which depresses the floor of the mouth during feeding strikes, shows faster contractile properties with growth. The objective of this study was to determine the molecular basis of these different scaling patterns. We examined the expression of two muscle proteins, myosin heavy chain (MyHC) and parvalbumin (PV), that affect contractile properties. We hypothesized that the relative contribution of slow and fast MyHC isoforms will modulate V(max) in these fishes, while the presence of PV in muscle will enhance rates of muscle relaxation. Myotomal muscle displays an increase in sMyHC expression with growth, in agreement with its physiological properties. Feeding muscles such as epaxial and sternohyoideus show no change or a decrease in sMyHC expression with growth, again as predicted from contractile properties. PV expression in myotomal muscle decreases with growth in both species, as has been seen in other fishes. The feeding muscles again show no change or an increase in PV expression with growth, contributing to faster contractile properties in these fishes. Both MyHC and PV appear to play important roles in modulating muscle contractile properties of swimming and feeding muscles in centrarchid fishes. PMID:22705556

  20. 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

  1. [Mechanism of action of clonidine in the forced-swimming test in mice].

    PubMed

    Malinge, M; Colombel, M C; Bourin, M

    1989-01-01

    Clonidine displays immobility-reducing effects in the mouse swimming model at doses (0.06-16 mg/kg IP) which decrease spontaneous motility. Tricyclic antidepressants evoke a similar dissociation in motor activity. The immobility-reducing effect of clonidine (1 mg/kg at 30 min pretesting) was reversed by yohimbine (4 mg/kg) but was unaffected by prazosin (2 mg/kg) or alpha-methyl-paratyrosine (100 mg/kg), and was enhanced by reserpine (2.5 mg/kg). Mediation by alpha-2 postjunctional receptors was thus suggested. However, two 5-HT receptor blockers--methysergide (2 mg/kg) and ketanserin (8 mg/kg)--increased this effect of clonidine whereas the non selective agonist 5-MeODMT (1 mg/kg) reduced clonidine action. Conversely, pretreatment with a subthreshold dose of clonidine (0.06 mg/kg at 45 min pretesting) made effective subthreshold doses of three 5-HT uptake inhibitors (citalopram 2 mg/kg, indalpine and fluvoxamine 4 mg/kg) and of the 5-HT1 receptor agonist 8-OH-DPAT (0.5 mg/kg). According to these data, the mouse swimming model would trigger functional relationships between central alpha-noradrenergic and serotonergic mechanisms.

  2. Strategies for swimming: explorations of the behaviour of a neuro-musculo-mechanical model of the lamprey

    PubMed Central

    Williams, Thelma L.; McMillen, Tyler

    2015-01-01

    ABSTRACT Experiments were performed on a neuro-musculo-mechanical model of a lamprey, to explore the strategies for controlling swimming speed. The muscle component of the model was based on previous experiments on isolated lamprey muscle. The patterns of muscle activation were those found in EMG studies on swimming lampreys. The fluid mechanics were modelled with G.I. Taylor's simplification. Tail beat frequencies of 2–6 sec−1 were combined with muscle activation strengths of 0.1% to 20% of maximum tetanic isometric strength. The resulting forward swimming speed and changing body shape were recorded. From the changing body shape the speed of the backward-travelling wave of curvature was calculated, as well as the ratio between the speeds of the waves of activation and curvature. For any given activation strength there was a tail beat frequency that gave maximal forward speed. Furthermore, for all the combinations of activation strength and tail beat frequency that gave such maximum swimming speeds, the ratio of the speed of the wave of curvature to the wave of muscle activation was approximately 0.75. This is similar to the ratio found in swimming lampreys. PMID:25661866

  3. Inorganic mercury accumulation in brain following waterborne exposure elicits a deficit on the number of brain cells and impairs swimming behavior in fish (white seabream-Diplodus sargus).

    PubMed

    Pereira, Patrícia; Puga, Sónia; Cardoso, Vera; Pinto-Ribeiro, Filipa; Raimundo, Joana; Barata, Marisa; Pousão-Ferreira, Pedro; Pacheco, Mário; Almeida, Armando

    2016-01-01

    The current study contributes to fill the knowledge gap on the neurotoxicity of inorganic mercury (iHg) in fish through the implementation of a combined evaluation of brain morphometric alterations (volume and total number of neurons plus glial cells in specific regions of the brain) and swimming behavior (endpoints related with the motor activity and mood/anxiety-like status). White seabream (Diplodus sargus) was exposed to realistic levels of iHg in water (2μgL(-1)) during 7 (E7) and 14 days (E14). After that, fish were allowed to recover for 28 days (PE28) in order to evaluate brain regeneration and reversibility of behavioral syndromes. A significant reduction in the number of cells in hypothalamus, optic tectum and cerebellum was found at E7, accompanied by relevant changes on swimming behavior. Moreover, the decrease in the number of neurons and glia in the molecular layer of the cerebellum was followed by a contraction of its volume. This is the first time that a deficit on the number of cells is reported in fish brain after iHg exposure. Interestingly, a recovery of hypothalamus and cerebellum occurred at E14, as evidenced by the identical number of cells found in exposed and control fish, and volume of cerebellum, which might be associated with an adaptive phenomenon. After 28 days post-exposure, the optic tectum continued to show a decrease in the number of cells, pointing out a higher vulnerability of this region. These morphometric alterations coincided with numerous changes on swimming behavior, related both with fish motor function and mood/anxiety-like status. Overall, current data pointed out the iHg potential to induce brain morphometric alterations, emphasizing a long-lasting neurobehavioral hazard.

  4. Altered burst swimming in rainbow trout Oncorhynchus mykiss exposed to natural and synthetic oestrogens.

    PubMed

    Osachoff, H L; Osachoff, K N; Wickramaratne, A E; Gunawardane, E K; Venturini, F P; Kennedy, C J

    2014-08-01

    Juvenile rainbow trout Oncorhynchus mykiss were exposed to two concentrations each of 17β-oestradiol (E2; natural oestrogen hormone) or 17α-ethinyl oestradiol (EE2; a potent synthetic oestrogen hormone) to evaluate their potential effects on burst-swimming performance. In each of six successive burst-swimming assays, burst-swimming speed (Uburst ) was lower in fish exposed to 0.5 and 1 µg l(-1) E2 and EE2 for four days compared with control fish. A practice swim (2 days prior to exposure initiation) in control fish elevated initial Uburst values, but this training effect was not evident in the 1 µg l(-1) EE2-exposed fish. Several potential oestrogen-mediated mechanisms for Uburst reductions were investigated, including effects on metabolic products, osmoregulation and blood oxygen-carrying capacity. Prior to burst-swimming trials, fish exposed to E2 and EE2 for 4 days had significantly reduced erythrocyte numbers and lower plasma glucose concentrations. After six repeated burst-swimming trials, plasma glucose, lactate and creatinine concentrations were not significantly different among treatment groups; however, plasma Cl(-) concentrations were significantly reduced in E2- and EE2-treated fish. In summary, E2 and EE2 exposure altered oxygen-carrying capacity ([erythrocytes]) and an osmoregulatory-related variable ([Cl(-) ]), effects that may underlie reductions in burst-swimming speed, which will have implications for fish performance in the wild. PMID:24930959

  5. Altered burst swimming in rainbow trout Oncorhynchus mykiss exposed to natural and synthetic oestrogens.

    PubMed

    Osachoff, H L; Osachoff, K N; Wickramaratne, A E; Gunawardane, E K; Venturini, F P; Kennedy, C J

    2014-08-01

    Juvenile rainbow trout Oncorhynchus mykiss were exposed to two concentrations each of 17β-oestradiol (E2; natural oestrogen hormone) or 17α-ethinyl oestradiol (EE2; a potent synthetic oestrogen hormone) to evaluate their potential effects on burst-swimming performance. In each of six successive burst-swimming assays, burst-swimming speed (Uburst ) was lower in fish exposed to 0.5 and 1 µg l(-1) E2 and EE2 for four days compared with control fish. A practice swim (2 days prior to exposure initiation) in control fish elevated initial Uburst values, but this training effect was not evident in the 1 µg l(-1) EE2-exposed fish. Several potential oestrogen-mediated mechanisms for Uburst reductions were investigated, including effects on metabolic products, osmoregulation and blood oxygen-carrying capacity. Prior to burst-swimming trials, fish exposed to E2 and EE2 for 4 days had significantly reduced erythrocyte numbers and lower plasma glucose concentrations. After six repeated burst-swimming trials, plasma glucose, lactate and creatinine concentrations were not significantly different among treatment groups; however, plasma Cl(-) concentrations were significantly reduced in E2- and EE2-treated fish. In summary, E2 and EE2 exposure altered oxygen-carrying capacity ([erythrocytes]) and an osmoregulatory-related variable ([Cl(-) ]), effects that may underlie reductions in burst-swimming speed, which will have implications for fish performance in the wild.

  6. 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.

  7. 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.

  8. 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.

  9. Maximum swimming speeds of sailfish and three other large marine predatory fish species based on muscle contraction time and stride length: a myth revisited

    PubMed Central

    Svendsen, Morten B. S.; Domenici, Paolo; Marras, Stefano; Krause, Jens; Boswell, Kevin M.; Rodriguez-Pinto, Ivan; Wilson, Alexander D. M.; Kurvers, Ralf H. J. M.; Viblanc, Paul E.; Finger, Jean S.; Steffensen, John F.

    2016-01-01

    ABSTRACT Billfishes are considered to be among the fastest swimmers in the oceans. Previous studies have estimated maximum speed of sailfish and black marlin at around 35 m s−1 but theoretical work on cavitation predicts that such extreme speed is unlikely. Here we investigated maximum speed of sailfish, and three other large marine pelagic predatory fish species, by measuring the twitch contraction time of anaerobic swimming muscle. The highest estimated maximum swimming speeds were found in sailfish (8.3±1.4 m s−1), followed by barracuda (6.2±1.0 m s−1), little tunny (5.6±0.2 m s−1) and dorado (4.0±0.9 m s−1); although size-corrected performance was highest in little tunny and lowest in sailfish. Contrary to previously reported estimates, our results suggest that sailfish are incapable of exceeding swimming speeds of 10-15 m s−1, which corresponds to the speed at which cavitation is predicted to occur, with destructive consequences for fin tissues. PMID:27543056

  10. Cell-body rocking is a dominant mechanism for flagellar synchronization in a swimming alga

    PubMed Central

    Geyer, Veikko F.; Jülicher, Frank; Howard, Jonathon; Friedrich, Benjamin M.

    2013-01-01

    The unicellular green alga Chlamydomonas swims with two flagella that can synchronize their beat. Synchronized beating is required to swim both fast and straight. A long-standing hypothesis proposes that synchronization of flagella results from hydrodynamic coupling, but the details are not understood. Here, we present realistic hydrodynamic computations and high-speed tracking experiments of swimming cells that show how a perturbation from the synchronized state causes rotational motion of the cell body. This rotation feeds back on the flagellar dynamics via hydrodynamic friction forces and rapidly restores the synchronized state in our theory. We calculate that this “cell-body rocking” provides the dominant contribution to synchronization in swimming cells, whereas direct hydrodynamic interactions between the flagella contribute negligibly. We experimentally confirmed the two-way coupling between flagellar beating and cell-body rocking predicted by our theory. PMID:24145440

  11. 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.

  12. 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.

  13. Physiological mechanisms used by fish to cope with salinity stress.

    PubMed

    Kültz, Dietmar

    2015-06-01

    Salinity represents a critical environmental factor for all aquatic organisms, including fishes. Environments of stable salinity are inhabited by stenohaline fishes having narrow salinity tolerance ranges. Environments of variable salinity are inhabited by euryhaline fishes having wide salinity tolerance ranges. Euryhaline fishes harbor mechanisms that control dynamic changes in osmoregulatory strategy from active salt absorption to salt secretion and from water excretion to water retention. These mechanisms of dynamic control of osmoregulatory strategy include the ability to perceive changes in environmental salinity that perturb body water and salt homeostasis (osmosensing), signaling networks that encode information about the direction and magnitude of salinity change, and epithelial transport and permeability effectors. These mechanisms of euryhalinity likely arose by mosaic evolution involving ancestral and derived protein functions. Most proteins necessary for euryhalinity are also critical for other biological functions and are preserved even in stenohaline fish. Only a few proteins have evolved functions specific to euryhaline fish and they may vary in different fish taxa because of multiple independent phylogenetic origins of euryhalinity in fish. Moreover, proteins involved in combinatorial osmosensing are likely interchangeable. Most euryhaline fishes have an upper salinity tolerance limit of approximately 2× seawater (60 g kg(-1)). However, some species tolerate up to 130 g kg(-1) salinity and they may be able to do so by switching their adaptive strategy when the salinity exceeds 60 g kg(-1). The superior salinity stress tolerance of euryhaline fishes represents an evolutionary advantage favoring their expansion and adaptive radiation in a climate of rapidly changing and pulsatory fluctuating salinity. Because such a climate scenario has been predicted, it is intriguing to mechanistically understand euryhalinity and how this complex

  14. 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.

  15. 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

  16. 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

  17. Effect of propelling surface size on the mechanics and energetics of front crawl swimming.

    PubMed

    Toussaint, H M; Janssen, T; Kluft, M

    1991-01-01

    In swimming the propulsive force is generated by giving a velocity change to masses of water. In this process energy is transferred from the swimmer to the water, which cannot be used to propel the swimmer. Theoretical considerations indicated that an increase of the propelling surface size should lead to a reduced loss of energy to the water. Thus, in this study, the effect of artificially enlarging the propelling surface of the hand was examined. The effect was examined in terms of the propelling efficiency during front crawl swimming using the arms alone. The legs were floated with a small buoy as previously described (Toussaint et al., J. appl. Physiol. 65, 2506-2512, 1988a). In ten competitive swimmers (six male, four female) the rate of energy expenditure (power input, Pi), power output (Po), work per stroke cycle (As), distance per stroke cycle (d), work per unit distance (Ad), and propelling efficiency (ep) were determined at various swimming speeds once with and once swimming without paddles. At the same average velocity the effect of swimming with paddles was to reduce Pi, Po, and Ad by 6, 7.6, and 7.5% respectively, but to increase ep and As by 7.8 and 7%. The increase in distance per stroke cycle and the decrease in stroke cycle frequency matched the predicted values based on the theoretical considerations in which the actual increase in propelling surface size was taken into account. PMID:2055909

  18. Bioinspired swimming simulations

    NASA Astrophysics Data System (ADS)

    Bergmann, Michel; Iollo, Angelo

    2016-10-01

    We present a method to simulate the flow past bioinspired swimmers starting from pictures of an actual fish. The overall approach requires i) a skeleton graph generation to get a level-set function from pictures; ii) optimal transportation to obtain the velocity on the body surface; iii) flow simulations realized with a Cartesian method based on penalization. This technique can be used to automate modeling swimming motion from data collected by biologists. We illustrate this paradigm by simulating the swimming of a mackerel fish.

  19. 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

  20. Fish Oil in Critical Illness: Mechanisms and Clinical Applications

    PubMed Central

    Stapleton, Renee D.; Martin, Julie M.; Mayer, Konstantin

    2015-01-01

    SYNOPSIS Fish oil is rich in omega-3 fatty acids which have been shown to be beneficial in multiple disease states that involve an inflammatory process. It is now hypothesized that omega-3 fatty acids may decrease the inflammatory response and be beneficial in critical illness. After a review of the mechanisms of omega-3 fatty acids in inflammation, research using enteral nutrition formulas and parenteral nutrition lipid emulsions fortified with fish oil are examined. The results of this research to date are inconclusive for both enteral and parenteral omega-3 fatty acid administration. More research is required before definitive recommendations can be made on fish oil supplementation in critical illness. PMID:20643303

  1. Determining the mechanism by which fish diversity influences production.

    PubMed

    Carey, Michael P; Wahl, David H

    2011-09-01

    Understanding the ability of biodiversity to govern ecosystem function is essential with current pressures on natural communities from species invasions and extirpations. Changes in fish communities can be a major determinant of food web dynamics, and even small shifts in species composition or richness can translate into large effects on ecosystems. In addition, there is a large information gap in extrapolating results of small-scale biodiversity-ecosystem function experiments to natural systems with realistic environmental complexity. Thus, we tested the key mechanisms (resource complementarity and selection effect) for biodiversity to influence fish production in mesocosms and ponds. Fish diversity treatments were created by replicating species richness and species composition within each richness level. In mesocosms, increasing richness had a positive effect on fish biomass with an overyielding pattern indicating species mixtures were more productive than any individual species. Additive partitioning confirmed a positive net effect of biodiversity driven by a complementarity effect. Productivity was less affected by species diversity when species were more similar. Thus, the primary mechanism driving fish production in the mesocosms was resource complementarity. In the ponds, the mechanism driving fish production changed through time. The key mechanism was initially resource complementarity until production was influenced by the selection effect. Varying strength of intraspecific interactions resulting from differences in resource levels and heterogeneity likely caused differences in mechanisms between the mesocosm and pond experiments, as well as changes through time in the ponds. Understanding the mechanisms by which fish diversity governs ecosystem function and how environmental complexity and resource levels alter these relationships can be used to improve predictions for natural systems.

  2. 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.

  3. 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

  4. PFOS affects posterior swim bladder chamber inflation and swimming performance of zebrafish larvae.

    PubMed

    Hagenaars, A; Stinckens, E; Vergauwen, L; Bervoets, L; Knapen, D

    2014-12-01

    Perfluorooctane sulphonate (PFOS) is one of the most commonly detected perfluorinated alkylated substances in the aquatic environment due to its persistence and the degradation of less stable compounds to PFOS. PFOS is known to cause developmental effects in fish. The main effect of PFOS in zebrafish larvae is an uninflated swim bladder. As no previous studies have focused on the effect of PFOS on zebrafish swim bladder inflation, the exact mechanisms leading to this effect are currently unknown. The objective of this study was to determine the exposure windows during early zebrafish development that are sensitive to PFOS exposure and result in impaired swim bladder inflation in order to specify the mechanisms by which this effect might be caused. Seven different time windows of exposure (1-48, 1-72, 1-120, 1-144, 48-144, 72-144, 120-144h post fertilization (hpf)) were tested based on the different developmental stages of the swim bladder. These seven time windows were tested for four concentrations corresponding to the EC-values of 1, 10, 80 and 95% impaired swim bladder inflation (EC1=0.70 mg L(-1), EC10=1.14 mg L(-1), EC80=3.07 mg L(-1) and EC95=4.28 mg L(-1)). At 6 days post fertilization, effects on survival, hatching, swim bladder inflation and size, larval length and swimming performance were assessed. For 0.70 mg L(-1), no significant effects were found for the tested parameters while 1.14 mg L(-1) resulted in a reduction of larval length. For 3.07 and 4.28 mg L(-1), the number of larvae affected and the severity of effects caused by PFOS were dependent on the time window of exposure. Exposure for 3 days or more resulted in significant reductions of swim bladder size, larval length and swimming speed with increasing severity of effects when the duration of exposure was longer, suggesting a possible effect of accumulated dose. Larvae that were only exposed early (1-48 hpf) or late (120-144 hpf) during development showed no effects on the studied endpoints

  5. 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.

  6. 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

  7. 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

  8. 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.

  9. 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

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

    PubMed

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

    2011-09-01

    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.

  11. 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

  12. 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

  13. 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."…

  14. A mechanism for acute aluminium toxicity in fish.

    PubMed

    Exley, C; Chappell, J S; Birchall, J D

    1991-08-01

    Aluminium is acutely toxic to fish in acid waters. The gill is the principal target organ and death is due to a combination of ionoregulatory, osmoregulatory and respiratory dysfunction. The toxic mechanism has hitherto received little direct consideration and is unknown. In this paper the mechanism of acute aluminium toxicity is approached from a chemical perspective. Symptomatic evidence of toxicity is taken from the literature and combined with our own research to elucidate a biochemically sound model to describe a possible mechanism of acute aluminium toxicity in fish. The proposed model delineates the chemical conditions immediately adjacent to the gill surface and emphasizes their importance in aluminium's toxic mode of action. The mechanism is shown to be bipartite. Aluminium binding to functional groups both apically located at the gill surface and intracellularly located within lamellar epithelial cells disrupts the barrier properties of the gill epithelium. The concomitant iono- and osmoregulatory dysfunction results in accelerated cell necrosis, sloughing and death of the fish. The mechanism of epithelial cell death is proposed as a general mechanism of aluminium-induced accelerated cell death.

  15. 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

  16. 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.

  17. Neuroendocrine mechanisms for immune system regulation during stress in fish.

    PubMed

    Nardocci, Gino; Navarro, Cristina; Cortés, Paula P; Imarai, Mónica; Montoya, Margarita; Valenzuela, Beatriz; Jara, Pablo; Acuña-Castillo, Claudio; Fernández, Ricardo

    2014-10-01

    In the last years, the aquaculture crops have experienced an explosive and intensive growth, because of the high demand for protein. This growth has increased fish susceptibility to diseases and subsequent death. The constant biotic and abiotic changes experienced by fish species in culture are challenges that induce physiological, endocrine and immunological responses. These changes mitigate stress effects at the cellular level to maintain homeostasis. The effects of stress on the immune system have been studied for many years. While acute stress can have beneficial effects, chronic stress inhibits the immune response in mammals and teleost fish. In response to stress, a signaling cascade is triggered by the activation of neural circuits in the central nervous system because the hypothalamus is the central modulator of stress. This leads to the production of catecholamines, corticosteroid-releasing hormone, adrenocorticotropic hormone and glucocorticoids, which are the essential neuroendocrine mediators for this activation. Because stress situations are energetically demanding, the neuroendocrine signals are involved in metabolic support and will suppress the "less important" immune function. Understanding the cellular mechanisms of the neuroendocrine regulation of immunity in fish will allow the development of new pharmaceutical strategies and therapeutics for the prevention and treatment of diseases triggered by stress at all stages of fish cultures for commercial production. PMID:25123831

  18. 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).

  19. Swimming Stroke Mechanical Efficiency and Physiological Responses of 100-m Backstroke with and without the use of paddles.

    PubMed

    Messinis, Spilios; Beidaris, Nikos; Messinis, Spyros; Soultanakis, Helen; Botonis, Petros; Platanou, Theodoros

    2014-03-27

    The use of swimming aids during training contributes to greater swimming efficiency by the improvement of the swimming specific power of the athlete. The purpose of this study was to compare the swimming stroke technical characteristics and the physiological responses of swimming 100-m backstroke, with and without the use of paddles at maximum and sub-maximum intensities at the same swimming speed. Eight swimmers competing at the national level participated in this study. The measurements took place at 4 different sessions. At every session, each participant swam individually one 100-m backstroke swimming trial with or without paddles at the same speed and two levels of intensity (100% and 85% of maximum speed). The results revealed lower stroke length, greater stroke number and gliding length without the use of swimming paddles at both intensities. Blood lactate concentration (10.03±2.96 vs. 5.85±2.23 mmol/l) and Rating of Perceived Exertion (17.43±2.07 vs. 12±2.82) were greater without the use of swimming paddles only at 100% of maximum speed. Thus, swimming backstroke with paddles compared to unaided swimming, at a similar speed, showed a greater efficiency at maximal but not at sub-maximal intensity. PMID:25031685

  20. Swimming Stroke Mechanical Efficiency and Physiological Responses of 100-m Backstroke with and without the use of paddles

    PubMed Central

    Messinis, Spilios; Beidaris, Nikos; Messinis, Spyros; Soultanakis, Helen; Botonis, Petros; Platanou, Theodoros

    2014-01-01

    The use of swimming aids during training contributes to greater swimming efficiency by the improvement of the swimming specific power of the athlete. The purpose of this study was to compare the swimming stroke technical characteristics and the physiological responses of swimming 100-m backstroke, with and without the use of paddles at maximum and sub-maximum intensities at the same swimming speed. Eight swimmers competing at the national level participated in this study. The measurements took place at 4 different sessions. At every session, each participant swam individually one 100-m backstroke swimming trial with or without paddles at the same speed and two levels of intensity (100% and 85% of maximum speed). The results revealed lower stroke length, greater stroke number and gliding length without the use of swimming paddles at both intensities. Blood lactate concentration (10.03±2.96 vs. 5.85±2.23 mmol/l) and Rating of Perceived Exertion (17.43±2.07 vs. 12±2.82) were greater without the use of swimming paddles only at 100% of maximum speed. Thus, swimming backstroke with paddles compared to unaided swimming, at a similar speed, showed a greater efficiency at maximal but not at sub-maximal intensity. PMID:25031685

  1. 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

  2. Role of central histaminergic mechanism in behavioural depression (swimming despair) in mice.

    PubMed

    Nath, C; Gulati, A; Dhawan, K N; Gupta, G P

    1988-01-01

    The role of the central histaminergic system in depression was studied by using swimming despair test in mice - a behavioural model of depression. In this test, immobility of mice reflects a state of depression. Intracerebral (ic) injection of histamine (50-200 micrograms) increased significantly the immobility. The H1-receptor blocker mepyramine (2.5-20 mg/kg ip) had no effect while H2-receptor blocker cimetidine (100-200 micrograms ic) caused a significant decrease in immobility. The histamine induced facilitation was blocked completely by cimetidine and antidepressant drugs-imipramine and desipramine, but remained unaffected in mice pretreated with mepyramine or atropine. The H2 agonist impromidine (20-40 micrograms ic) also enhanced significantly, the immobility which was blocked by cimetidine and antidepressant drugs. It has been concluded that central H2-receptors facilitate depression and antidepressant drugs block central H2-receptors.

  3. 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.

  4. Swimming physiology.

    PubMed

    Holmér, I

    1992-05-01

    Swimming takes place in a medium, that presents different gravitational and resistive forces, respiratory conditions and thermal stress compared to air. The energy cost of propulsion in swimming is high, but a considerable reduction occurs at a given velocity as result of regular swim training. In medley swimmers the energy cost is lowest for front crawl, followed by backstroke, butterfly and breast-stroke. Cardiac output is probably not limiting for performance since swimmers easily achieve higher values during running. Maximal heart rate, however, is lowered by approx. 10 beats/min during swimming compared to running. Most likely active muscle mass is smaller and rate of power production lesser in swimming. Local factors, such as peripheral circulation, capillary density, perfusion pressure and metabolic capacity of active muscles, are important determinants of the power production capacity and emphasize the role of swim specific training movements. Improved swimming technique and efficiency are likely to explain much of the continuous progress in performance. Rational principles based on improved understanding of the biomechanics and physiology of swimming should be guidelines for swimmers and coaches in their efforts to explore the limits of human performance. PMID:1642724

  5. [Progress on the degeneration mechanism of cave fishes' eyes].

    PubMed

    Gu, Xian; Ning, Tiao; Xiao, Heng

    2012-08-01

    Attempts to understand the degeneration of the eyes in cave fish has largely been explained by either various extents of gradual degeneration, ranging from partial to total loss, observed in various species or by acceleration of loss caused by dark environments. However, neither the theory of biological evolution developed by Charles Darwin nor the neutral theory of molecular evolution formulated by Kimura Motoo adequately explains these phenomena. Recent trends in utilizing multidisciplinary research, however, have yielded better results, helping reveal a more complex picture of the mechanisms of degeneration. Here, we summarize the current progress of the research via morphology and anatomy, development biology, animal behavior science and molecular genetics, and offer some perspectives on the ongoing research into the development and degeneration of eyes in cave fish.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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

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

    PubMed Central

    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

  15. Glutathione transferase theta in apical ciliary tuft regulates mechanical reception and swimming behavior of Sea Urchin Embryos

    PubMed Central

    Jin, Yinhua; Yaguchi, Shunsuke; Shiba, Kogiku; Yamada, Lixy; Yaguchi, Junko; Shibata, Daisuke; Sawada, Hitoshi; Inaba, Kazuo

    2013-01-01

    An apical tuft, which is observed in a wide range of embryos/larvae of marine invertebrates, is composed of a group of cilia that are longer and less motile than the abundant lateral cilia covering the rest of the embryonic surface. Although the apical tuft has been thought to function as a sensory organ, its molecular composition and roles are poorly understood. Here, we identified a glutathione transferase theta (GSTT) as an abundant and specific component of the apical tuft in sea urchin embryos. The expression of GSTT mRNA increases and becomes limited to the animal plate of the mesenchyme blastula, gastrula, and prism larva. Electron microscopy and tandem mass spectrometry demonstrated that the apical tuft contains almost every axonemal component for ciliary motility. Low concentrations of an inhibitor of glutathione transferase bromosulphophthalein (BSP) induce bending of apical tuft, suggesting that GSTT regulates motility of apical tuft cilia. Embryos treated with BSP swim with normal velocity and trajectories but show less efficiency of changing direction when they collide with an object. These results suggest that GSTT in the apical tuft plays an important role in the mechanical reception for the motility regulation of lateral motile cilia in sea urchin embryos. PMID:23907936

  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. Costs of swimming measured at optimum speed: scale effects, differences between swimming styles, taxonomic groups and submerged and surface swimming.

    PubMed

    Videler, J J; Nolet, B A

    1990-01-01

    1. Data on swimming energy expenditure of 30 submerged and nine surface swimmers, covering different swimming styles and taxonomic groups, are selected from the literature. 2. The costs of transport at the optimum speed are compared and related to body mass and Re numbers. 3. Fish and turtles use relatively less and most surface swimmers slightly more energy than the other submerged swimmers; man and mink are poorly adapted to swimming. 4. The metabolic rate in W at optimum speed is approximately equal to the body mass in kg for fish and turtles and three times the mass figure for the other submerged swimmers. PMID:1982941

  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 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)…

  20. 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

  1. Selecting the swimming mechanisms of colloidal particles: bubble propulsion versus self-diffusiophoresis.

    PubMed

    Wang, Sijia; Wu, Ning

    2014-04-01

    Bubble propulsion and self-diffusiophoresis are two common mechanisms that can drive autonomous motion of microparticles in hydrogen peroxide. Although microtubular particles, when coated with platinum in their interior concave surfaces, can propel due to the formation and release of bubbles from one end, the convex Janus particles usually do not generate any visible bubble. They move primarily due to the self-diffusiophoresis. Coincidentally, the platinum films on those particles were typically coated by physical evaporation. In this paper, we use a simple chemical deposition method to make platinum-polystyrene Janus dimers. Surprisingly, those particles are propelled by periodic growth and collapse of bubbles on the platinum-coated lobes. We find that both high catalytic activity and rough surface are necessary to change the propulsion mode from self-diffusiophoresis to bubble propulsion. Our Janus dimers, with combined geometric and interfacial anisotropy, also exhibit distinctive motions at the respective stages of bubble growth and collapse, which differ by 5-6 orders of magnitude in time. Our study not only provides insight into the link between self-diffusiophoresis and bubble propulsion but also reveals the intriguing impacts of the combined geometric and interfacial anisotropy on self-propulsion of particles.

  2. Swim-training changes the spatio-temporal dynamics of skeletogenesis in zebrafish larvae (Danio rerio).

    PubMed

    Fiaz, Ansa W; Léon-Kloosterziel, Karen M; Gort, Gerrit; Schulte-Merker, Stefan; van Leeuwen, Johan L; Kranenbarg, Sander

    2012-01-01

    Fish larvae experience many environmental challenges during development such as variation in water velocity, food availability and predation. The rapid development of structures involved in feeding, respiration and swimming increases the chance of survival. It has been hypothesized that mechanical loading induced by muscle forces plays a role in prioritizing the development of these structures. Mechanical loading by muscle forces has been shown to affect larval and embryonic bone development in vertebrates, but these investigations were limited to the appendicular skeleton. To explore the role of mechanical load during chondrogenesis and osteogenesis of the cranial, axial and appendicular skeleton, we subjected zebrafish larvae to swim-training, which increases physical exercise levels and presumably also mechanical loads, from 5 until 14 days post fertilization. Here we show that an increased swimming activity accelerated growth, chondrogenesis and osteogenesis during larval development in zebrafish. Interestingly, swim-training accelerated both perichondral and intramembranous ossification. Furthermore, swim-training prioritized the formation of cartilage and bone structures in the head and tail region as well as the formation of elements in the anal and dorsal fins. This suggests that an increased swimming activity prioritized the development of structures which play an important role in swimming and thereby increasing the chance of survival in an environment where water velocity increases. Our study is the first to show that already during early zebrafish larval development, skeletal tissue in the cranial, axial and appendicular skeleton is competent to respond to swim-training due to increased water velocities. It demonstrates that changes in water flow conditions can result into significant spatio-temporal changes in skeletogenesis.

  3. 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…

  4. 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.

  5. 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.

  6. 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

  7. 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

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

    PubMed

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

    2011-03-12

    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.

  9. 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.

  10. 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.

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. Swimming injuries. An overview.

    PubMed

    McMaster, W C

    1996-11-01

    Most injuries and complaints encountered in swimming athletes are repetitive microtrauma or overuse, and successful management does not usually require surgical intervention. Rest and other measures to reduce inflammation are often required. Many injuries originate from faulty techniques or mechanisms, and an assessment must be made of the swimming biomechanics of any injured athlete to identify faults that may contribute to injury. It is also important to look at the total training programme of the athlete to identify other factors, such as weight training or dry land programmes, that may be contributing to injury. It is important to understand that, while rest or reduced training may be necessary, every effort to keep the swimmer "in the water' should be made, as cessation of training may lead to a rapid detraining effect.

  17. 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.

  18. 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.

  19. 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

  20. 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

  1. Swimming dynamics of bidirectional artificial flagella

    NASA Astrophysics Data System (ADS)

    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.

  2. 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.

  3. Kinematics of plaice, Pleuronectes platessa, and cod, Gadus morhua, swimming near the bottom.

    PubMed

    Webb, Paul W

    2002-07-01

    The kinematics of plaice (Pleuronectes platessa, L=22.1 cm) and cod (Gadus morhua, L=25.0 cm, where L is total fish length) swimming at various speeds at the bottom and lifted to heights, h, of 10, 50 and 100 mm by a thin-wire grid were measured. For cod, tailbeat frequency, amplitude, body and fin span and propulsive wavelength were unaffected by h and varied with speed as described for fusiform pelagic species. In contrast, the kinematics of plaice was affected by h. Body and fin spans and propulsive wavelength were independent of swimming speed and h. Tailbeat amplitude was independent of swimming speed, but averaged 1.5 cm at h=0 and 2.5 cm at h> or = 10 mm. Plaice tailbeat frequency increased with swimming speed for fish at the bottom but was independent of swimming speed at h=10, 50 and 100 mm, averaging 4.6, 6.0 and 5.8 Hz respectively. Total mechanical power, P, produced by propulsive movements calculated from the bulk-momentum form of elongated slender-body theory was similar for cod and plaice swimming at the bottom but, at h> or = 10 mm, P for plaice was larger than that for cod. Plaice support their weight in water by swimming at a small tilt angle. The small changes in swimming kinematics with swimming speed are attributed to decreasing induced power costs to support the weight as speed increases. The contribution of the tail to power output increased monotonically with the tail gap/span ratio, z/B, for z/B=0.23 (h=0 mm) to z/B=1.1 (h=50 mm). The smaller tailbeat amplitude of the tail decreased both z/B and the power output for plaice swimming at the bottom. For the maximum body and fin span of plaice, the contribution to power output increased for local z/B values of 0.044 (h-0 mm) to 0.1 (h=10 mm) and declined somewhat at larger values of z/B. The smaller effect of the bottom on power output of the large-span anterior body sections may result from the resorption of much of the upstream wake at the re-entrant downstream tail.

  4. A fast-starting mechanical fish that accelerates at 40 m s(-2).

    PubMed

    Conte, J; Modarres-Sadeghi, Y; Watts, M N; Hover, F S; Triantafyllou, M S

    2010-09-01

    We have built a simple mechanical system to emulate the fast-start performance of fish. The system consists of a thin metal beam covered by a urethane rubber, the fish body and an appropriately shaped tail. The body form of the mechanical fish was modeled after a pike species and selected because it is a widely-studied fast-start specialist. The mechanical fish was held in curvature and hung in water by two restraining lines, which were simultaneously released by a pneumatic cutting mechanism. The potential energy in the beam was transferred into the fluid, thereby accelerating the fish. We measured the resulting acceleration, and calculated the efficiency of propulsion for the mechanical fish model, defined as the ratio of the final kinetic energy of the fish and the initially stored potential energy in the body beam. We also ran a series of flow visualization tests to observe the resulting flow patterns. The maximum start-up acceleration was measured to be around 40 m s(-2), with the maximum final velocity around 1.2 m s(-1). The form of the measured acceleration signal as function of time is quite similar to that of type I fast-start motions studied by Harper and Blake (1991 J. Exp. Biol. 155 175-92). The hydrodynamic efficiency of the fish was found to be around 10%. Flow visualization of the mechanical fast-start wake was also analyzed, showing that the acceleration peaks are associated with the shedding of two vortex rings in near-lateral directions.

  5. Swimming in the California sea lion: morphometrics, drag and energetics.

    PubMed

    Feldkamp, S D

    1987-09-01

    During swimming, the California sea lion, Zalophus californianus (Lesson), generates thrust forces solely by means of its pectoral flippers. This study examines the drag, energetic cost and efficiency associated with this method of locomotion. Sea lions are highly streamlined, with a fineness ratio of 5.5 and maximum girth at 40% of body length. This profile leads to reduced drag and swimming power requirements. Films of gliding animals showed the drag coefficient (based on wetted surface area) to be 0.0042 at a Reynolds number of 2.0 X 10(6). This value is comparable to that found for other aquatic vertebrates and suggests that the sea lion's morphology helps to delay turbulent separation and maintain laminar flow over the forward portion of its body. Swimming metabolism was measured in a water flume at velocities up to 1.3 ms-1. Effective swimming speeds up to 2.7 ms-1 were attained by increasing each animal's drag. Oxygen consumption rose exponentially with velocity and for two animals was best described as VO2 = 6.27e0.48U, where VO2 is in mlO2 min-1 kg-1 and U is in ms-1. Minimum cost of transport for these animals was 0.12 ml O2 kg-1 m-1 at a relative speed of 1.4 body lengths s-1. This is 2.5 times that predicted for a fish of similar size. Swimming efficiencies were determined from these results using power output values calculated from the measured drag coefficient and standard hydrodynamic equations. At the highest velocity, aerobic efficiency reached a maximum of 15% while mechanical efficiency of the foreflippers was 80%. The results demonstrate that foreflipper propulsion is a highly efficient and comparatively inexpensive method of locomotion in aquatic mammals. PMID:3694112

  6. 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

  7. Kinematics and hydrodynamics analysis of swimming anurans reveals striking inter-specific differences in the mechanism for producing thrust.

    PubMed

    Richards, Christopher T

    2010-02-15

    This study aimed to compare the swimming kinematics and hydrodynamics within and among aquatic and semi-aquatic/terrestrial frogs. High-speed video was used to obtain kinematics of the leg joints and feet as animals swam freely across their natural range of speeds. Blade element analysis was then used to model the hydrodynamic thrust as a function of foot kinematics. Two purely aquatic frogs, Xenopus laevis and Hymenochirus boettgeri, were compared with two semi-aquatic/terrestrial frogs, Rana pipiens and Bufo americanus. The four species performed similarly. Among swimming strokes, peak stroke velocity ranged from 3.3+/-1.1 to 20.9+/-2.5, from 6.8+/-2.1 to 28.6+/-3.7 and from 4.9+/-0.5 to 20.9+/-4.1 body lengths per second (BL s(-1)) in X. laevis, H. boettgeri and R. pipiens, respectively (means +/- s.d.; N=4 frogs for each). B. americanus swam much more slowly at 3.1+/-0.3 to 7.0+/-2.0 BL s(-1) (N=3 frogs). Time-varying joint kinematics patterns were superficially similar among species. Because foot kinematics result from the cumulative motion of joints proximal to the feet, small differences in time-varying joint kinematics among species resulted in species-specific foot kinematics (therefore hydrodynamics) patterns. To obtain a simple measure of the hydrodynamically useful motion of the foot, this study uses 'effective foot velocity' (EFV): a measure of the component of foot velocity along the axis of swimming. Resolving EFV into translational and rotational components allows predictions of species-specific propulsion strategies. Additionally, a novel kinematic analysis is presented here that enables the partitioning of translational and rotational foot velocity into velocity components contributed by extension at each individual limb joint. Data from the kinematics analysis show that R. pipiens and B. americanus translated their feet faster than their body moved forward, resulting in positive net translational EFV. Conversely, translational EFV was slower than

  8. Stroke Drills for Swimming Instructors.

    ERIC Educational Resources Information Center

    Cahill, Peter J.

    1982-01-01

    Stroke drills to be used by swimming instructors to teach four competitive swim strokes are described. The drills include: one arm swims; (2) alternative kicks; (3) fist swims; and (4) catch-up strokes. (JN)

  9. An interspecific comparison between morphology and swimming performance in cyprinids.

    PubMed

    Yan, G-J; He, X-K; Cao, Z-D; Fu, S-J

    2013-08-01

    Flow regimes are believed to be of major evolutionary significance in fish. The flow regimes inhabited by cyprinids vary extensively from still flow regimes to riptide flow regimes. To test (i) whether flow-driven swimming performance and relevant morphological differentiation are present among fish species and (ii) whether evolutionary shifts between high-flow and low-flow habitats in cyprinids are associated with evolutionary trade-offs in locomotor performance, we obtained data on both steady and unsteady swimming performance and external body shape for 19 species of cyprinids that typically occur in different flow regimes (still, intermediate and riptide). We also measured the routine energy expenditure (RMR) and maximum metabolic rate (MMR) and calculated the optimal swimming speed. Our results showed that fish species from riptide groups tend to have a higher critical swimming speed (Ucrit ), maximum linear velocity (Vmax ) and fineness ratio (FR) than fish from the other two groups. However, there was no correlation between the reconstructed changes in the steady and unsteady swimming performance of the 19 species. According to the phylogenetically independent contrast (PIC) method, the Ucrit was actively correlated with the MMR. These results indicated that selection will favour both higher steady and unsteady swimming performance and a more streamlined body shape in environments with high water velocities. The results suggested that steady swimming performance was more sensitive to the flow regime and that for this reason, changes in body shape resulted more from selective pressure on steady swimming performance than on unsteady swimming performance. No evolutionary trade-off was observed between steady and unsteady swimming performance, although Ucrit and MMR were found to have coevolved. However, a further analysis within each typically occurring habitat group suggested that the trade-off that may exist between steady and unsteady swimming performance

  10. 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.

  11. The shoulder in competitive swimming.

    PubMed

    Richardson, A B; Jobe, F W; Collins, H R

    1980-01-01

    Shoulder pain is the most common orthopaedic problem in competitive swimming. In a group of 137 of this country's best swimmers, 58 had had symptoms of "swimmer's shoulder." Population characteristics of this group indicated that symptoms increased with the caliber of the athlete, were slightly more common in men, and were related to sprint rather than distance swimming. The use of hand-paddle training exacerbated symptoms, which were more common during the early and middle season. Consideration of shoulder mechanics in swimming reveals that freestyle, butterfly, and backstroke require similar motions; a swimmer using any of these strokes is susceptible to developing shoulder pain. Swimmer's shoulder represents chronic irritation of the humeral head and rotator cuff on the coracoacromial arch during abduction of the shoulder, the so-called impingement syndrome. Treatment included stretching, rest, ice therapy, oral antiinflammatory agents, judicious use of injectable steroids, and surgery as a last resort. PMID:7377446

  12. Active drag, useful mechanical power output and hydrodynamic force coefficient in different swimming strokes at maximal velocity.

    PubMed

    Kolmogorov, S V; Duplishcheva, O A

    1992-03-01

    By comparing the time of the same distance swum with and without an added resistance, under the assumption of an equal power output in both cases, the drag of 73 top swimmers was estimated. The active drag Fr(a.d.) at maximal swimming velocities varied considerably across strokes and individuals. In the females Fr(a.d.) ranged from 69.78 to 31.16 N in the front-crawl, from 83.04 to 37.78 N in dolphin, from 93.56 to 45.19 N in breaststroke, and from 65.51 to 37.79 N in back-stroke. In the males Fr(a.d.) ranged from 167.11 to 42.23 N in front-crawl, from 156.09 to 46.95 N in dolphin, from 176.87 to 55.61 N in breaststroke, and from 146.28 to 46.36 N in back-stroke. Also, the ratio of Fr(a.d.) to the passive drag Fr(a.d.) as determined for the analogical velocity in a tugging condition (in standard body position-front gliding) shows considerable individual variations. In the female swimmers variations in Fr(a.d.)/Fr(p.d.) ranged from 145.17 to 59.94% in front-crawl, from 192.39 to 85.57% in dolphin, from 298.03 to 124.50% in breaststroke, and from 162.87 to 85.61% in back-stroke. In the male swimmers variations in Fr(a.d.)/Fr(p.d.) ranged from 162.24 to 62.39% in front-crawl, from 191.70 to 70.38% in dolphin, from 295.57 to 102.83% in breaststroke, and from 198.82 to 74.48% in back-stroke. The main reason for such variations is found in the individual features of swimming technique and can be quantitatively estimated with the hydrodynamic force coefficient, which thus provides an adequate index of technique. PMID:1564064

  13. The antiviral defense mechanisms in mandarin fish induced by DNA vaccination against a rhabdovirus.

    PubMed

    Chen, Zhong-Yuan; Lei, Xiao-Ying; Zhang, Qi-Ya

    2012-06-15

    Plasmid DNAs containing Siniperca chuatsi rhabdovirus (SCRV) glycoprotein gene (pcDNA-G) and nucleoprotein gene (pcDNA-N) were constructed, and used to determine the antiviral immune response elicited by DNA vaccination in mandarin fish. In vitro and in vivo expression of the plasmid constructs was confirmed in transfected cells and muscle tissues of vaccinated fish by Western blot, indirect immunofluorescence or RT-PCR analysis. Fish injected with pcDNA-G exhibited protective effect against SCRV challenge with a relative percent survival (RPS) of 77.5%, but no significant protection (RPS of 2.5%) was observed in fish vaccinated with pcDNA-N. Immunohistochemical analysis showed that vaccination with pcDNA-G decreased histological lesions and suppressed the virus replication in fish target organs, e.g. kidney, liver, spleen, gill and heart. Transcriptional analysis further revealed that the expression levels of type I IFN system genes including interferon regulation factor-7 (IRF-7) gene, myxovirus resistance (Mx) gene and virus inhibitory protein (Viperin) gene were strongly up-regulated after injection with pcDNA-G, whereas the level of transcription of immunoglobulin M (IgM) gene did not show a statistically significant change. These results reveal that type I IFN antiviral immune response is rapidly triggered by the plasmid DNA containing rhabdovirus glycoprotein gene in fish, which offers an explanation of molecular mechanisms for DNA vaccination inducing mandarin fish resist to SCRV disease.

  14. 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.

  15. 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.

  16. 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.

  17. 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...

  18. 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.

  19. Evaluation of Fish-Injury Mechanisms During Exposure to a High-Velocity Jet

    SciTech Connect

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

    2003-01-24

    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 {center_dot} s{sup -1}). 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. This is presumably because age-0 fish have less mass and inertia, and therefore sustain smaller forces on exposed organs during acceleration. Alternatively, age-0 fish were substantially more susceptible to behavioral impairments such as disorientation. This may also relate to the smaller mass of the age-0 fish. The less massive age-0 fish sustain larger accelerations and jerks, which may be important sources of the internal injuries to the vestibular and neurological systems. All the dynamic parameters computed from the bulk motion of the fish (velocity, jerk, and force

  20. Social plasticity in fish: integrating mechanisms and function.

    PubMed

    Oliveira, R F

    2012-12-01

    Social plasticity is a ubiquitous feature of animal behaviour. Animals must adjust the expression of their social behaviour to the nuances of daily social life and to the transitions between life-history stages, and the ability to do so affects their Darwinian fitness. Here, an integrative framework is proposed for understanding the proximate mechanisms and ultimate consequences of social plasticity. According to this framework, social plasticity is achieved by rewiring or by biochemically switching nodes of the neural network underlying social behaviour in response to perceived social information. Therefore, at the molecular level, it depends on the social regulation of gene expression, so that different brain genomic and epigenetic states correspond to different behavioural responses and the switches between states are orchestrated by signalling pathways that interface the social environment and the genotype. At the evolutionary scale, social plasticity can be seen as an adaptive trait that can be under positive selection when changes in the environment outpace the rate of genetic evolutionary change. In cases when social plasticity is too costly or incomplete, behavioural consistency can emerge by directional selection that recruits gene modules corresponding to favoured behavioural states in that environment. As a result of this integrative approach, how knowledge of the proximate mechanisms underlying social plasticity is crucial to understanding its costs, limits and evolutionary consequences is shown, thereby highlighting the fact that proximate mechanisms contribute to the dynamics of selection. The role of teleosts as a premier model to study social plasticity is also highlighted, given the diversity and plasticity that this group exhibits in terms of social behaviour. Finally, the proposed integrative framework to social plasticity also illustrates how reciprocal causation analysis of biological phenomena (i.e. considering the interaction between

  1. 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.

  2. 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.

  3. 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 ...

  4. 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 ...

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. Swimming and the heart.

    PubMed

    Lazar, Jason M; Khanna, Neel; Chesler, Roseann; Salciccioli, Louis

    2013-09-20

    Exercise training is accepted to be beneficial in lowering morbidity and mortality in patients with cardiac disease. Swimming is a popular recreational activity, gaining recognition as an effective option in maintaining and improving cardiovascular fitness. Swimming is a unique form of exercise, differing from land-based exercises such as running in many aspects including medium, position, breathing pattern, and the muscle groups used. Water immersion places compressive forces on the body with resulting physiologic effects. We reviewed the physiologic effects and cardiovascular responses to swimming, the cardiac adaptations to swim training, swimming as a cardiac disease risk factor modifier, and the effects of swimming in those with cardiac disease conditions such as coronary artery disease, congestive heart failure and the long-QT syndrome.

  10. Low-Reynolds-number swimming near a wall

    NASA Astrophysics Data System (ADS)

    Li, Gaojin; Ardekani, Arezoo

    2013-11-01

    Hydrodynamics of swimming organisms in a low Reynolds number regime near a no-slip wall has been a subject of growing interest in recent years because of its importance in many health and environmental problems. In addition to the changes in the swimming speed and energy expenditure of organisms in the presence of a wall, unexpected interesting swimming dynamics has been reported in recent experiments. In this study, the hydrodynamics of an archetypal low-Reynolds number swimmer, called ``squirmers,'' near a wall has been numerically studied. Depending on the swimming mechanism and swimming direction, three different modes are distinguished: (a) squirmer escaping from the wall, (b) squirmer swimming along the wall keeping a constant height and orientation angle and (c) squirmer swimming near the wall in a periodic trajectory. This work is supported by NSF Grant No. CBET-1150348-CAREER.

  11. Applied physiology of swimming.

    PubMed

    Lavoie, J M; Montpetit, R R

    1986-01-01

    Scientific research in swimming over the past 10 to 15 years has been oriented toward multiple aspects that relate to applied and basic physiology, metabolism, biochemistry, and endocrinology. This review considers recent findings on: 1) specific physical characteristics of swimmers; 2) the energetics of swimming; 3) the evaluation of aerobic fitness in swimming; and 4) some metabolic and hormonal aspects related to swimmers. Firstly, the age of finalists in Olympic swimming is not much different from that of the participants from other sports. They are taller and heavier than a reference population of the same age. The height bias in swimming may be the reason for lack of success from some Asian and African countries. Experimental data point toward greater leanness, particularly in female swimmers, than was seen 10 years ago. Overall, female swimmers present a range of 14 to 19% body fat whereas males are much lower (5 to 10%). Secondly, the relationship between O2 uptake and crawl swimming velocity (at training and competitive speeds) is thought to be linear. The energy cost varies between strokes with a dichotomy between the 2 symmetrical and the 2 asymmetrical strokes. Energy expenditure in swimming is represented by the sum of the cost of translational motion (drag) and maintenance of horizontal motion (gravity). The cost of the latter decreases as speed increases. Examination of the question of size-associated effects on the cost of swimming using Huxley's allometric equation (Y = axb) shows an almost direct relationship with passive drag. Expressing energy cost in litres of O2/m/kg is proposed as a better index of technical swimming ability than the traditional expression of VO2/distance in L/km. Thirdly, maximal direct conventional techniques used to evaluate maximal oxygen consumption (VO2 max) in swimming include free swimming, tethered swimming, and flume swimming. Despite the individual peculiarities of each method, with similar experimental conditions

  12. Applied physiology of swimming.

    PubMed

    Lavoie, J M; Montpetit, R R

    1986-01-01

    Scientific research in swimming over the past 10 to 15 years has been oriented toward multiple aspects that relate to applied and basic physiology, metabolism, biochemistry, and endocrinology. This review considers recent findings on: 1) specific physical characteristics of swimmers; 2) the energetics of swimming; 3) the evaluation of aerobic fitness in swimming; and 4) some metabolic and hormonal aspects related to swimmers. Firstly, the age of finalists in Olympic swimming is not much different from that of the participants from other sports. They are taller and heavier than a reference population of the same age. The height bias in swimming may be the reason for lack of success from some Asian and African countries. Experimental data point toward greater leanness, particularly in female swimmers, than was seen 10 years ago. Overall, female swimmers present a range of 14 to 19% body fat whereas males are much lower (5 to 10%). Secondly, the relationship between O2 uptake and crawl swimming velocity (at training and competitive speeds) is thought to be linear. The energy cost varies between strokes with a dichotomy between the 2 symmetrical and the 2 asymmetrical strokes. Energy expenditure in swimming is represented by the sum of the cost of translational motion (drag) and maintenance of horizontal motion (gravity). The cost of the latter decreases as speed increases. Examination of the question of size-associated effects on the cost of swimming using Huxley's allometric equation (Y = axb) shows an almost direct relationship with passive drag. Expressing energy cost in litres of O2/m/kg is proposed as a better index of technical swimming ability than the traditional expression of VO2/distance in L/km. Thirdly, maximal direct conventional techniques used to evaluate maximal oxygen consumption (VO2 max) in swimming include free swimming, tethered swimming, and flume swimming. Despite the individual peculiarities of each method, with similar experimental conditions

  13. 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)

  14. Pigment patterns in adult fish result from superimposition of two largely independent pigmentation mechanisms.

    PubMed

    Ceinos, Rosa M; Guillot, Raúl; Kelsh, Robert N; Cerdá-Reverter, José M; Rotllant, Josep

    2015-03-01

    Dorso-ventral pigment pattern differences are the most widespread pigmentary adaptations in vertebrates. In mammals, this pattern is controlled by regulating melanin chemistry in melanocytes using a protein, agouti-signalling peptide (ASIP). In fish, studies of pigment patterning have focused on stripe formation, identifying a core striping mechanism dependent upon interactions between different pigment cell types. In contrast, mechanisms driving the dorso-ventral countershading pattern have been overlooked. Here, we demonstrate that, in fact, zebrafish utilize two distinct adult pigment patterning mechanisms - an ancient dorso-ventral patterning mechanism, and a more recent striping mechanism based on cell-cell interactions; remarkably, the dorso-ventral patterning mechanism also utilizes ASIP. These two mechanisms function largely independently, with resultant patterns superimposed to give the full pattern.

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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

  20. 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

  1. 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

  2. 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.

  3. 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

  4. Hypoxia tolerance variance between swimming and resting striped bass Morone saxatilis.

    PubMed

    Nelson, J A; Lipkey, G K

    2015-08-01

    Individual striped bass Morone saxatilis were each exposed in random order to aquatic hypoxia (10% air saturation) either while swimming at 50% of their estimated critical swimming speed (Ucrit ) or while at rest until they lost equilibrium. Individuals were always less tolerant of hypoxia when swimming (P < 0.01); the average fish was over five times more tolerant to the same hypoxia exposure when not swimming. There was no relationship between an individual's rank order of hypoxia tolerance (HT) under the two flow regimes, suggesting that different factors determine an individual's HT when at rest than when swimming. PMID:26184582

  5. Hypoxia tolerance variance between swimming and resting striped bass Morone saxatilis.

    PubMed

    Nelson, J A; Lipkey, G K

    2015-08-01

    Individual striped bass Morone saxatilis were each exposed in random order to aquatic hypoxia (10% air saturation) either while swimming at 50% of their estimated critical swimming speed (Ucrit ) or while at rest until they lost equilibrium. Individuals were always less tolerant of hypoxia when swimming (P < 0.01); the average fish was over five times more tolerant to the same hypoxia exposure when not swimming. There was no relationship between an individual's rank order of hypoxia tolerance (HT) under the two flow regimes, suggesting that different factors determine an individual's HT when at rest than when swimming.

  6. Teach Your Child Swimming.

    ERIC Educational Resources Information Center

    Gorton, B.E.

    This illustrated guide provides basic knowledge that will enable parents to teach their children to swim, starting from the first visit to the pool up to the development of higher water skills. All the main swimming strokes are dealt with, and the appropriate teaching stages are described. The teaching of starts and turns for each stroke and other…

  7. 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…

  8. 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

  9. 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

  10. 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

  11. 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.

  12. Aerobic and anaerobic swimming performance of individual Atlantic cod.

    PubMed

    Reidy, S P; Kerr, S R; Nelson, J A

    2000-01-01

    Individual Atlantic cod (Gadus morhua) were exercised using three different measures of swimming performance. (1) An endurance test (critical swimming speed, U(crit), protocol) designed to assess predominantly aerobic endurance swimming (duration hours). (2) An acceleration test (U(burst)), in which the fish were required to swim against a rapidly increasing current until exhausted (duration minutes). This test was designed to assess predominantly glycolytic-based swimming capacity. (3) A sprint test that examined the animals' ability to swim away from a sudden stimulus (duration seconds). Rates of oxygen consumption ( mdot (O2)) during the endurance test and various morphological variables of the individual fish were also measured. Both aerobic and anaerobic swimming performance of individual cod were found to be significantly repeatable over a 3 month period. mdot (O2) during the U(crit) protocol was also significantly repeatable at intermediate to high swimming speeds, but not at low speeds. Our results support extrapolation from metabolic rates at incremented swimming speeds to zero activity as the best way to measure standard metabolic rate in cod. While performance in the U(crit) test and the sprint test were positively correlated, there was a negative correlation between performance in the U(crit) test and performance in the U(burst) test. This implies a potential trade-off in individual cod between stamina and the ability to use glycolytic-based locomotion. Inter-individual variation in swimming performance during these protocols, while substantial, was not correlated with individual variation in fin surface areas, age or morphology. However, U(burst) performance was dependent upon the sex of the animals, while performance during the U(crit) protocol was significantly correlated with their aerobic scope for activity.

  13. 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.

  14. Lead toxicity on non-specific immune mechanisms of freshwater fish Channa punctatus.

    PubMed

    Paul, Nilantika; Chakraborty, Samujjwal; Sengupta, Mahuya

    2014-07-01

    Lead has no known role in the body that is physiologically relevant, and its harmful effects are myriad. Lead from the atmosphere and soil ends up in water bodies thus affecting the aquatic organisms. This situation has thus prompted numerous investigations on the effects of this metal on the biological functions of aquatic organisms, particularly on immune mechanisms in fish. This paper addresses the immunotoxicologic effects of lead acetate in intestinal macrophages of freshwater fish Channa punctatus. Fish were exposed to lead acetate (9.43mg/l) for 4 days. When checked for its effects on macrophages, it was noted that lead interfered with bacterial phagocytosis, intracellular killing capacity and cell adhesion as well as inhibited release of antimicrobial substances like nitric oxide (NO) and myeloperoxidase (MPO). On giving bacterial challenge with Staphylococcus aureus to intestinal macrophages of both control and lead treated groups, the macrophages showed significantly higher concentration of viable bacteria in the intracellular milieu in lead treated group as compared to control. We also report that in vivo exposure to lead acetate inhibits phagocytosis, which is evident from a reduced phagocytic index of treated group from that of the control. The amount of MPO and NO released by the control cells was also reduced significantly upon in vivo lead treatment. The property of antigenic adherence to the macrophage cell membrane, a vital process in phagocytosis, was significantly decreased in the treated group as compared to control. Severe damage in intestinal epithelium, disarrangement and fragmentation of mucosal foldings was observed in lead treated group when compared with the untreated group. The present results also showed decreased tumor necrosis factor-alpha (TNF-α) level upon metal exposure in sera as well as cell lysate of lead exposed fish thus, implicating both MAPK signaling pathways as well as NFκβ signaling. We thus conclude that lead affects

  15. [Individual differences in behavior and mechanisms of ecological differentiation with fishes as an example].

    PubMed

    Budaev, S V; Mikheev, V N; Pavlov, D S

    2015-01-01

    In this paper we present a review of individual differences in animal behavior exemplified by fishes. Main approaches to these differences investigation are outlined. Such terms as temperament can be used to describe consistent characteristics of individuality in animals. It should be emphasized that consistency over time and across situations is the main classification characteristic of the temperament trait. We also briefly review genetic and physiological mechanisms of individuality in fish, factors affecting their development in the ontogeny, and effects of the individual experience. Significant adaptive value of temperament is shown: in many cases the natural selection maintains alternative behavioral tactics. We also consider the main quantitative models accounting for the coexistence of individuals with different behavioral patterns. Finally, it is demonstrated that patterns of behavioral individuality may significantly affect population dynamics.

  16. 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

  17. 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.

  18. 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.

  19. Energetics of underwater swimming with SCUBA.

    PubMed

    Pendergast, D R; Tedesco, M; Nawrocki, D M; Fisher, N M

    1996-05-01

    Underwater swimming has unique features of breathing apparatus (SCUBA), thermal protective gear, and fins. The energy cost of underwater swimming is determined by the drag while swimming and the net mechanical efficiency. These are influenced by the cross-sectional area of the diver and gear and the frequency of the leg kick. The speeds that divers can achieve are relatively low, thus the VO(2) increases linearly with values of VO(2)*d(-1) of 30-50 l*km(-1)for women and men, respectively. Diving experience had little effect on VO(2) for women; however, male divers with experience had lower VO(2) than beginners. The location and density of the gear can alter the diver's attitude in the water and increase the energy cost of swimming by 30 percent at slow speeds. The type of fin used has an effect on the depth and frequency of the kick, thus on drag and efficiency, with a range of VO(2) from 25 to 50 l*km(-1). A large flexible fin had the lowest energy cost and a large rigid fin the highest. Adding extra air tanks or a dry suit increased the cost of swimming by 25 percent. The energy cost of underwater swimming is influenced by gender, gear and its placement, fin type, and experience of the diver.

  20. 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.

  1. 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.…

  2. Antarctic Fishes.

    ERIC Educational Resources Information Center

    Eastman, Joseph T.; DeVries, Arthur L.

    1986-01-01

    Explains the adaptations to Antarctic waters that Notothenioidei, a group of advanced bony fishes, have exhibited. Discusses the fishes' mechanisms of production of antifreeze properties and their capacities for neutral buoyancy in water. (ML)

  3. [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

  4. 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.

  5. 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.

  6. 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

  7. 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

  8. An Annotated Bibliography of Experimental Research concerning Competitive Swimming.

    ERIC Educational Resources Information Center

    Bachman, John C.

    This annotated bibliography has been compiled as a guide for the researcher of swimming in referring to experimental studies in the physiological, mechanical, psychological, and medical aspects of swimming. The studies have been briefly annotated to enable the reader to quickly determine the salient points the authors made in their studies. The…

  9. How does the diffusion fish swim?

    NASA Astrophysics Data System (ADS)

    Peng, Gunnar; Balmforth, Neil; Young, William

    2015-11-01

    An asymmetric object (such as a wedge) placed in a stably stratified fluid moves with a steady horizontal speed. We explain how this spontaneous motion is caused by the diffusion-driven buoyancy layers that form on the sloping surfaces of the object, and calculate the speed for a variety of two-dimensional configurations using the method of matched asymptotic expansions. Surprisingly, in many cases, the leading-order speed depends on neither the viscosity nor the stratification strength. This work was completed at the 2015 WHOI GFD Program, which is supported by the National Science Foundation and the Office of Naval Research.

  10. 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

  11. 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

  12. 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

  13. Cortisol emphasizes the metabolic strategies employed by common carp, Cyprinus carpio at different feeding and swimming regimes.

    PubMed

    Liew, Hon Jung; Chiarella, Daniela; Pelle, Antonella; Faggio, Caterina; Blust, Ronny; De Boeck, Gudrun

    2013-11-01

    The objective of this study was to investigate the interaction between feeding, exercise and cortisol on metabolic strategies of common carp over a 168h post-implant period. Feeding provided readily available energy and clearly increased muscle and liver protein and glycogen stores. Swimming, feeding and cortisol all induced aerobic metabolism by increasing oxygen consumption, and stimulated protein metabolism as demonstrated by the increased ammonia and urea excretion and ammonia quotient. Hypercortisol stimulated ammonia self-detoxifying mechanisms by enhancing ammonia and urea excretion, especially during severe exercise. At high swimming level, higher branchial clearance rates in cortisol treated fish succeeded in eliminating the elevation of endogenous ammonia, resulting in reduced plasma Tamm levels compared to control and sham implanted fish. Carp easily induced anaerobic metabolism, both during routine and active swimming, with elevated lactate levels as a consequence. Both feeding and cortisol treatment increased this dependence on anaerobic metabolism. Hypercortisol induced both glycogenesis and gluconeogenesis resulting in hyperglycemia and muscle and liver glycogen deposition, most likely as a protective mechanism for prolonged stress situations and primarily fuelled by protein mobilization.

  14. 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

  15. 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.

  16. 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.

  17. Features, boundaries and connecting mechanisms of the Mauritanian Province exemplified by oceanic fish larvae

    NASA Astrophysics Data System (ADS)

    John, H. Ch.; Zelck, C.

    1997-08-01

    The Mauritanian Province, which comprises the area from the NW-African shelf to about 20°W and from Cape Timiris to Cape Verde, is redefined on the basis of fish larvae distribution patterns, direct and indirect current measurements, CTD-O2 hydrography and SST-remote sensing. Its northern and western boundaries coincide with, the permanent, although not stationary, Cape-Verde-Frontal-Zone separating North- and South-Atlantic-Central-Water masses. Its southern boundary is characterized by tropical temperatures throughout the year. The oceanic Mauritanian Province is a myctophid dominated system that lacks genuine endemic species. Many deep-mesopelagic species of Myctophidae as well as other families are absent or rare in its centre, whilst some northern oceanic Myctophidae acquire a pseudoceanic character and prosper. On the other hand, tropical species of both oceanic and neritic origin co-occur alongside such cold-temperate Myctophidae. Distribution patterns of fish larvae were partly directly dependent on currents intruding into the province and partly indirectly on the impact of the circulation system on the local hydrography. Local hydrography could affect the survival capability of either larvae or adults. While an oxygen deficit southeast of the frontal zone is a limiting factor for subsurface-epipelagic and mesopelagic species, southwestward Ekman-drift and the related temperature deficit hampers the intrusion or survival of tropical fish larvae with neustonic or shallow vertical distribution. Southern, deep living or eurybathic species with lower temperature preferences are transported into or even beyond the province by northward currents. A transport model describing the input/output mechanisms of the province and defining its limiting features is presented and discussed in respect to recent literature.

  18. Electric signals and schooling behavior in a weakly electric fish, Marcusenius cyprinoides L. (Mormyriformes).

    PubMed

    Moller, P

    1976-08-20

    Field recordings of electric organ discharges and catches of Marcusenius cyprinoides showed that these electric fish form groups and move about in schools. The role electric organ discharges in group cohesion was investigated by comparing interactions in groups of intact and operated, electrically silent fish. The absence of electric organ dischares reduced locomotor activity and resulted in the disappearance of two behaviors: parallel lineup and single file swimming. Electric signals are considered part of a schooling mechanism that aids the fish in maintaining group cohesion in their turbid enviornment and during migration at night.

  19. Use of chemical mixtures to differentiate mechanisms of endocrine action in a small fish model.

    PubMed

    Ankley, Gerald T; Jensen, Kathleen M; Kahl, Michael D; Durhan, Elizabeth J; Makynen, Elizabeth A; Cavallin, Jenna E; Martinović, Dalma; Wehmas, Leah C; Mueller, Nathaniel D; Villeneuve, Daniel L

    2010-09-01

    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. These assays can be sensitive and highly diagnostic for key mechanisms such as agonism of the estrogen and androgen receptors (ERs, ARs) and inhibition of steroid synthesis. However, most of the tests do not unambiguously identify AR antagonists. The purpose of this work was to explore the utility of a mixture test design with the fathead minnow (Pimephales promelas) for detecting different classes of EDCs including AR antagonists. Adults of both sexes were exposed via the water to EDCs with diverse mechanisms of action in the absence or presence of 17beta-trenbolone (TB), a potent AR agonist which masculinizes female fathead minnows. Similar to previous studies with the model AR antagonists flutamide and vinclozolin, exposure of females to the AR antagonist cyproterone acetate in the presence of TB decreased expression of an easily-observed masculinization response, nuptial tubercle formation. Mixture studies with TB and the model ER agonists, 17alpha-ethinylestradiol and bisphenol A, also showed inhibition of tubercle formation in the females, but unlike the AR antagonists, the estrogens markedly induced synthesis of vitellogenin (VTG: egg yolk protein), particularly in males. The ER agonists also offset TB-induced depressions in plasma VTG concentrations in female fish. Additional mixture experiments were conducted with TB and triclocarban, an anti-microbial reported to enhance AR-mediated responses, or ammonia, a "negative control" with no known direct effects on HPG function. Neither chemical affected VTG status in males or females in the absence or presence of TB; however, both slightly enhanced TB-induced tubercle formation in females. Based on studies described herein and elsewhere with the fathead minnow, a TB co-exposure assay appears to be an effective

  20. Sex differences associated with intermittent swim stress.

    PubMed

    Warner, Timothy A; Libman, Matthew K; Wooten, Katherine L; Drugan, Robert C

    2013-11-01

    Various animal models of depression have been used to seek a greater understanding of stress-related disorders. However, there is still a great need for novel research in this area, as many individuals suffering from depression are resistant to current treatment methods. Women have a higher rate of depression, highlighting the need to investigate mechanisms of sex differences. Therefore, we employed a new animal model to assess symptoms of depression, known as intermittent swim stress (ISS). In this model, the animal experiences 100 trials of cold water swim stress. ISS has already been shown to cause signs of behavioral depression in males, but has yet to be assessed in females. Following ISS exposure, we looked at sex differences in the Morris water maze and forced swim test. The results indicated a spatial learning effect only in the hidden platform task between male and female controls, and stressed and control males. A consistent spatial memory effect was only seen for males exposed to ISS. In the forced swim test, both sexes exposed to ISS exhibited greater immobility, and the same males and females also showed attenuated climbing and swimming, respectively. The sex differences could be due to different neural substrates for males and females. The goal of this study was to provide the first behavioral examination of sex differences following ISS exposure, so the stage of estrous cycle was not assessed for the females. This is a necessary future direction for subsequent experiments. The current article highlights the importance of sex differences in response to stress.

  1. 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.

  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. Effects of acute and chronic waterborne lead exposure on the swimming performance and aerobic scope of fathead minnows (Pimephales promelas).

    PubMed

    Mager, Edward M; Grosell, Martin

    2011-06-01

    Fathead minnows were subjected to an incremental velocity test using swim tunnel respirometry for the analysis of aerobic scope and swimming performance, as critical aerobic swim speed (U(crit)), following chronic exposures (33-57 ) to 0.9±0.4, 157±18 or 689±66 nmol L⁻¹ Pb and an acute exposure (24 h) to 672±35 nmol L⁻¹ Pb (mean±SEM). Assessment of Pb-induced anemia and neurological impairment were evaluated by blood hemoglobin (Hb) concentrations and a cost of transport (COT) analysis, respectively. Fish from the acute 672±35 nmol L⁻¹ Pb (24.4±1.2 BL s⁻¹) and chronic 689±66 nmol L⁻¹ Pb (24.6±0.9 BL s⁻¹) treatments exhibited reduced U(crits) compared to control fish (27.6±0.8 BL s⁻¹). Aerobic scope was reduced by acute Pb exposure (8.6±2.6 μmol O₂ g⁻¹ h⁻¹ vs. 22.6±3.8 μmol O₂ g⁻¹ h⁻¹ from controls) owing to a decrease in maximum oxygen consumption rate (38.8±0.8 μmol O₂ g⁻¹ h⁻¹ vs. 54.0±4.2 μmol O₂ g⁻¹ h⁻¹ from controls). However, no effect on aerobic scope was observed with fish chronically exposed to Pb. Significant differences were not observed for Hb concentrations or COT. These findings suggest that the impaired swimming performances arising from acute and chronic Pb exposures reflect different mechanisms of toxicity.

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

    PubMed

    Borazjani, Iman; Daghooghi, Mohsen

    2013-04-01

    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.

  5. 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.

  6. 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.

  7. 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.

  8. Synchronization of Swimming Microorganisms

    NASA Astrophysics Data System (ADS)

    Elfring, Gwynn; Lauga, Eric

    2009-11-01

    Flagellated eukaryotic cells (such as spermatozoa) have been observed to synchronize their flagella when swimming in close proximity. Using a 2D model, we find that hydrodynamic interactions alone can lead to synchronization if the waveforms of the flagella display front-back asymmetry. Depending on the nature of the asymmetry, the phase-locked conformation can minimize or maximize the energy dissipated by the co-swimming cells. We show that due to kinematic reversibility, this front-back asymmetry is necessary for synchronization in a Newtonian fluid, and discuss the differences in a non-Newtonian fluid.

  9. 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.

  10. 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

  11. Automated visual tracking for studying the ontogeny of zebrafish swimming.

    PubMed

    Fontaine, Ebraheem; Lentink, David; Kranenbarg, Sander; Müller, Ulrike K; van Leeuwen, Johan L; Barr, Alan H; Burdick, Joel W

    2008-04-01

    The zebrafish Danio rerio is a widely used model organism in studies of genetics, developmental biology, and recently, biomechanics. In order to quantify changes in swimming during all stages of development, we have developed a visual tracking system that estimates the posture of fish. Our current approach assumes planar motion of the fish, given image sequences taken from a top view. An accurate geometric fish model is automatically designed and fit to the images at each time frame. Our approach works across a range of fish shapes and sizes and is therefore well suited for studying the ontogeny of fish swimming, while also being robust to common environmental occlusions. Our current analysis focuses on measuring the influence of vertebra development on the swimming capabilities of zebrafish. We examine wild-type zebrafish and mutants with stiff vertebrae (stocksteif) and quantify their body kinematics as a function of their development from larvae to adult (mutants made available by the Hubrecht laboratory, The Netherlands). By tracking the fish, we are able to measure the curvature and net acceleration along the body that result from the fish's body wave. Here, we demonstrate the capabilities of the tracking system for the escape response of wild-type zebrafish and stocksteif mutant zebrafish. The response was filmed with a digital high-speed camera at 1500 frames s(-1). Our approach enables biomechanists and ethologists to process much larger datasets than possible at present. Our automated tracking scheme can therefore accelerate insight in the swimming behavior of many species of (developing) fish.

  12. 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

  13. 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

  14. Observations on side-swimming rainbow trout in water recirculation aquaculture systems.

    PubMed

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

    2014-12-01

    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 Pco2. 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. PMID:25250476

  15. Observations on side-swimming rainbow trout in water recirculation aquaculture systems.

    PubMed

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

    2014-12-01

    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 Pco2. 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.

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

    PubMed

    Felderhof, B U

    2015-01-01

    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.

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

    PubMed

    Felderhof, B U

    2015-01-01

    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

  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. 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.

  1. 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)

  2. 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

  3. Bending continuous structures with SMAs: a novel robotic fish design.

    PubMed

    Rossi, C; Colorado, J; Coral, W; Barrientos, A

    2011-12-01

    In this paper, we describe our research on bio-inspired locomotion systems using deformable structures and smart materials, concretely shape memory alloys (SMAs). These types of materials allow us to explore the possibility of building motor-less and gear-less robots. A swimming underwater fish-like robot has been developed whose movements are generated using SMAs. These actuators are suitable for bending the continuous backbone of the fish, which in turn causes a change in the curvature of the body. This type of structural arrangement is inspired by fish red muscles, which are mainly recruited during steady swimming for the bending of a flexible but nearly incompressible structure such as the fishbone. This paper reviews the design process of these bio-inspired structures, from the motivations and physiological inspiration to the mechatronics design, control and simulations, leading to actual experimental trials and results. The focus of this work is to present the mechanisms by which standard swimming patterns can be reproduced with the proposed design. Moreover, the performance of the SMA-based actuators' control in terms of actuation speed and position accuracy is also addressed.

  4. [Safety evaluation of food from transgenic fish and the molecular biological mechanism].

    PubMed

    Zhang, Xichun; Yang, Xiaoguang

    2004-03-01

    More progresses have been made in the studying of transgenic fish in China, but the studying work of safety evaluation of food from transgenic fish are started up just now. Compared to plants and animals on the land, it is more difficult to control the mobility of fish and fish can give birth to a large number of offsprings, so the ecological risk or hazard about transgenic fish is more critical than others. Another safety problem is the chimerism which is initiated by the gene transfer methods used in the transgenic fish. Getting sterile triploid transgenic fish and fixed point integration are efficient to solve the two problems above respectively. The solution of the two problems are also the basis of safety evaluation and detection of food from transgenic fish. Up to now, there are little reports on the safety evaluation of transgenic fish including nutritional evaluation and allergic reaction, and there are no basic research on the detection of transgenic fish for the aim of food safety. In brief, it is very urgent to start up the research on the safety evaluation and detection of transgenic fish for the control of food safety.

  5. 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

  6. 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.

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. Use of pneumocystoplasty for overinflation of the swim bladder in a goldfish.

    PubMed

    Britt, Tara; Weisse, Chick; Weber, E Scott; Matzkin, Zach; Klide, Alan

    2002-09-01

    A Ryukin goldfish was evaluated because of a 6-month history of progressive abdominal distention and positive buoyancy. Overinflation of the swim bladder was diagnosed, and the fish was anesthetized with tricaine methanesulfonate. Archimedes' principle was used to determine the volume of swim bladder that was removed surgically. The caudal swim bladder was exteriorized through an abdominal incision and 2 surgical clips were placed across it to limit its size. After surgery, the fish remained in a state of negative buoyancy in sternal and lateral recumbency on the bottom of the tank. Sutures were removed 15 days after surgery, but the fish died 24 days after surgery. A full necropsy could not be performed because of autolysis of the tissues, but the surgical clips and the swim bladder appeared unremarkable. Pneumocystoplasty may be a viable treatment for this condition. PMID:12216910

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. Going for a Swim

    ERIC Educational Resources Information Center

    Covington, Savannah

    2016-01-01

    Is anything more refreshing than going for a nice, long swim? The math scenarios presented in this article will take the reader back to hot summer days and remind the reader what a cool dip in the water feels like. Solving these problems is enjoyable and encourages the solver to think of the many ways that math is all around--even in the middle of…

  19. 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.

  20. 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

  1. 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.

  2. Why fishes have a fish shape

    NASA Astrophysics Data System (ADS)

    Eloy, Christophe; Schouveiler, Lionel

    2010-11-01

    The relation between form and function for elongated swimmers is revisited by solving a multi-objective optimization problem. We consider elongated fishes of varying elliptic cross-section whose motion is prescribed by a time-periodic curvature. The two semi-axes of the cross-section, the curvature amplitude and phase are assumed to vary continuously along the fish length. Hydrodynamic forces acting on such fishes are modeled in the elongated-body limit by considering both reactive and resistive forces. Applying Newton's second law, the heave and pitch amplitude and phase, as well as the swimming velocity can be found. The total power needed can also be calculated yielding the swimming efficiency. The multi-objective optimization consists in finding the fish shape and associated motion which corresponds to maximum efficiency, maximum velocity or any trade-off between the two. This optimization problem is solved using a genetic algorithm whose principle is to start with an initial random population and to evolve it by mutation and selection. We find that the most efficient shape resembles existing fishes and arguments are given to explain the relation between this particular fish form and performance.

  3. 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.

  4. 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.

  5. Mechanisms of vasodilation in the dorsal aorta of the elephant fish, Callorhinchus milii (Chimaeriformes: Holocephali).

    PubMed

    Jennings, Brett L; Bell, Justin D; Hyodo, Susumu; Toop, Tes; Donald, John A

    2007-07-01

    This study investigated vasodilator mechanisms in the dorsal aorta of the elephant fish, Callorhinchus milii, using anatomical and physiological approaches. Nitric oxide synthase could only be located in the perivascular nerve fibres and not the endothelium of the dorsal aorta, using NADPH histochemistry and immunohistochemistry. In vitro organ bath experiments demonstrated that a NO/soluble guanylyl cyclase (GC) system appeared to be absent in the vascular smooth muscle, since the NO donors SNP (10(-4) mol l(-1)) and SIN-1 (10(-5) mol l(-1)) were without effect. Nicotine (3 x 10(-4) mol l(-1)) mediated a vasodilation that was not affected by ODQ (10(-5) mol l(-1)), L-NNA (10(-4) mol l(-1)), indomethacin (10(-5) mol l(-1)), or removal of the endothelium. In contrast, the voltage-gated sodium channel inhibitor, tetrodotoxin (10(-5) mol l(-1)), significantly decreased the dilation induced by nicotine, suggesting that it contained a neural component. Pre-incubation of the dorsal aorta with the calcitonin gene-related peptide (CGRP) receptor antagonist, CGRP(8-37) (10(-6) mol l(-1)) also caused a significant decrease in the nicotine-induced dilation. We propose that nicotine is mediating a neurally-derived vasodilation in the dorsal aorta that is independent of NO, prostaglandins and the endothelium, and partly mediated by CGRP. PMID:17342492

  6. Effect of Mechanically Deboned Chicken Meat Hydrolysates on the Physicochemical Properties of Imitation Fish Paste

    PubMed Central

    Jin, Sang-Keun; Go, Gwang-woong; Jung, Eun-Young; Lim, Hyun-Jung; Yang, Han-Sul; Park, Jae-Hong

    2014-01-01

    This study investigated on the effects of adding mechanically deboned chicken meat (MDCM) hydrolysates on the quality properties of imitation fish paste (IFP) during storage. IFP was prepared from Alaska Pollack, spent laying hens surimi and protein hydrolysates which were enzymatically extracted from MDCM. The study was designed as a 3×4 factorial design with three MDCM hydrolysate content groups (0%, 0.4%, and 0.8%) and four storage times (0, 2, 4, and 6 weeks). Addition of MDCM hydrolysates increased crude fat content but lowered water content (p<0.05). The breaking force of IFP, an indicator of gel formation, increased in treated groups compared to control (p<0.05). Angiotensin I-converting enzyme (ACE) activity was inhibited and free radical scavenging activity increased with increasing MDCM hydrolysate content (p<0.05). In conclusion, the addition of MDCM to IFP improves gel characteristics. Additionally, protein hydrolysates from MDCM serve as a potential source of ACE inhibiting peptides. PMID:25049933

  7. 'Optimal' vortex rings and aquatic propulsion mechanisms

    NASA Astrophysics Data System (ADS)

    Linden, Paul; Turner, Stewart

    2004-11-01

    Fish swim by flapping their tail and other fins. Other sea creatures, such as squid and salps, eject fluid intermittently as a jet. We discuss the fluid mechanics behind these propulsion mechanisms, and show that these animals produce optimal vortex rings, which give the maximum thrust for a given energy input. We show fish optimise both their steady swimming and their ability to accelerate and turn by producing an individual optimal ring with each flap of the tail or fin. Salps produce vortex rings directly by ejecting a volume of fluid through a rear orifice, and these are also optimal. An important implication of this paper is that the repetition of vortex production is not necessary for an individual vortex to have the `optimal' characteristics.

  8. Interspecific variation in hypoxia tolerance, swimming performance and plasticity in cyprinids that prefer different habitats.

    PubMed

    Fu, Shi-Jian; Fu, Cheng; Yan, Guan-Jie; Cao, Zhen-Dong; Zhang, An-Jie; Pang, Xu

    2014-02-15

    This study quantified and compared hypoxia tolerance and swim performance among cyprinid fish species from rapid-, slow- and intermediate-flow habitats (four species per habitat) in China. In addition, we explored the effects of short-term acclimation on swim performance, maximum metabolic rate (M(O2,max)) and gill remodelling to detect habitat-associated patterns of plastic response to hypoxia. Indices of hypoxia tolerance included oxygen threshold for loss of equilibrium (LOE50) and aquatic surface respiration (ASR50), and critical oxygen tension for routine metabolic rate (Pcrit). Critical swimming speed (Ucrit) and M(O2,max) were measured under normoxic and hypoxic conditions after 48 h acclimation to normoxia and hypoxia, and gill remodelling was estimated after 48 h of hypoxia exposure. Both traditional ANCOVA and phylogenetically independent contrast (PDANOVA) analyses showed that fish species from rapid-flow habitats exhibited lower LOE50 compared with fish from intermediate- and slow-flow habitats. Habitat-specific differences in Pcrit and Ucrit were detected using PDANOVA but not traditional ANCOVA analyses, with fish species from rapid-flow habitats exhibiting lower Pcrit but higher Ucrit values compared with fish from intermediate- and slow-flow habitats. Fish species from rapid-flow habitats were also characterized by less plasticity in swim performance and gill morphology in response to hypoxia acclimation compared with species from slow-flow habitats, but a greater drop in swim performance in response to acute hypoxia exposure. The study detected a habitat-specific difference in hypoxia tolerance, swimming performance and its plasticity among fish from habitats with different flow conditions, possibly because of the long-term adaptation to the habitat caused by selection stress. The PDANOVA analyses were more powerful than traditional statistical analyses according to the habitat effects in both hypoxia tolerance and swimming performance in this

  9. Locomotory behaviour and post-exercise physiology in relation to swimming speed, gait transition and metabolism in free-swimming smallmouth bass (Micropterus dolomieu).

    PubMed

    Peake, Stephan J; Farrell, Anthony P

    2004-04-01

    We examined swimming behaviour, gait recruitment and post-exercise muscle glycogen, muscle lactate, plasma lactate and oxygen consumption in smallmouth bass (Micropterus dolomieu; 24-38 cm fork length) that voluntarily ascended a 25 m raceway against water velocities ranging from 40 to 120 cm s(-1). Physiological parameters were referenced to additional measurements made following exhaustive exercise in a static tank and aerobic exercise in a swim tunnel. Maximum speeds maintained exclusively using a steady gait in the raceway ranged from 53.6 to 97.3 cm s(-1) and scaled positively with fish length. Minimum swimming speeds maintained exclusively through recruitment of an unsteady gait were also positively correlated to fish length and ranged from 81.4 to 122.9 cm s(-1). Fish switched between steady and unsteady swimming at intermediate speeds. Smallmouth bass always maintained a positive ground speed in the raceway; however, those that primarily swam using a steady gait to overcome low to moderate water velocities (20-50 cm s(-1)) maintained mean ground speeds of approximately 20 cm s(-1). By contrast, mean ground speeds of fish that primarily recruited an unsteady locomotory gait increased significantly with water velocity, which resulted in an inverse relationship between exercise intensity and duration. We interpret this behaviour as evidence that unsteady swimming was being fuelled by the limited supply of anaerobic substrates in the white muscle. This hypothesis is supported by the fact that unsteady swimming fish showed significantly lower muscle glycogen levels, higher lactate concentrations (muscle and plasma) and higher post-exercise oxygen consumption rates compared with fish that used a steady gait. The reduction in passage time achieved by fish using an unsteady gait allowed them to ascend the raceway with relatively minor post-exercise metabolic imbalances, relative to individuals chased to exhaustion.

  10. A therapeutic TDS patch of Metformin from a HPMC-PVA blend studied with a biological membrane of fish-swim bladder: An approach for dermal application in NIDDM.

    PubMed

    Shaheen, Sharif Mohammad; Jahan, Lubna; Ferdaus, Rahat

    2015-09-01

    In order to introduce an easily applicable, removable, painless and long-term drug delivery system for non-insulin dependent diabetes mellitus (NIDDM), hydroxyl propyl methyl cellulose with polyvinyl alcohol (HPMC-PVA) blend patches of metormin HCl were evaluated in vitro and in vivo. A suitable patch of metformin 800 mg with HPMC-PVA blend were used, following a three cycle freeze-thaw technique. Drug release kinetic profiles were performed in both patch and swim bladder. Albino mice were artificially generated as NIDDM mice by alloxan insertion i.p and after then treated with the therapeutic patch. Blood glucose was estimated by commercially available glucose kit based on glucose oxidase method. Drug release parameters from the patch and swim bladder were typical non-Fickian diffusion and both have the same kinetic constant, revealing its possible diffusion through stratum corneum. Hypoglycemia was observed in treatment of normal mice with TDDS of metformin HCl within 4 hours i.e. 25 ± 2.13 mg/dl and within 16 hours in diabetic rats blood glucose level returned to normal level i.e. from 360 ± 3.3 mg/dl (NIDDM level) to 105 ± 2.5 mg/dl (Normal level). The TDS-patch has got the same kinetic simulation with that of swim-bladder, which might be a prediction for in vivo application. Here metformin was delivered to diabetic mice and has got significant anti-diabetic effect can be considered as a kind of patch for NIDDM just like wearing and taking off a hand watch because hypoglycaemia can be removed by just taking off the patch.

  11. A therapeutic TDS patch of Metformin from a HPMC-PVA blend studied with a biological membrane of fish-swim bladder: An approach for dermal application in NIDDM.

    PubMed

    Shaheen, Sharif Mohammad; Jahan, Lubna; Ferdaus, Rahat

    2015-09-01

    In order to introduce an easily applicable, removable, painless and long-term drug delivery system for non-insulin dependent diabetes mellitus (NIDDM), hydroxyl propyl methyl cellulose with polyvinyl alcohol (HPMC-PVA) blend patches of metormin HCl were evaluated in vitro and in vivo. A suitable patch of metformin 800 mg with HPMC-PVA blend were used, following a three cycle freeze-thaw technique. Drug release kinetic profiles were performed in both patch and swim bladder. Albino mice were artificially generated as NIDDM mice by alloxan insertion i.p and after then treated with the therapeutic patch. Blood glucose was estimated by commercially available glucose kit based on glucose oxidase method. Drug release parameters from the patch and swim bladder were typical non-Fickian diffusion and both have the same kinetic constant, revealing its possible diffusion through stratum corneum. Hypoglycemia was observed in treatment of normal mice with TDDS of metformin HCl within 4 hours i.e. 25 ± 2.13 mg/dl and within 16 hours in diabetic rats blood glucose level returned to normal level i.e. from 360 ± 3.3 mg/dl (NIDDM level) to 105 ± 2.5 mg/dl (Normal level). The TDS-patch has got the same kinetic simulation with that of swim-bladder, which might be a prediction for in vivo application. Here metformin was delivered to diabetic mice and has got significant anti-diabetic effect can be considered as a kind of patch for NIDDM just like wearing and taking off a hand watch because hypoglycaemia can be removed by just taking off the patch. PMID:26408881

  12. Simulations of neuromuscular control in lamprey swimming.

    PubMed Central

    Ekeberg, O; Grillner, S

    1999-01-01

    The neuronal generation of vertebrate locomotion has been extensively studied in the lamprey. Models at different levels of abstraction are being used to describe this system, from abstract nonlinear oscillators to interconnected model neurons comprising multiple compartments and a Hodgkin-Huxley representation of the most relevant ion channels. To study the role of sensory feedback by simulation, it eventually also becomes necessary to incorporate the mechanical movements in the models. By using simplifying models of muscle activation, body mechanics, counteracting water forces, and sensory feedback through stretch receptors and vestibular organs, we have been able to close the feedback loop to enable studies of the interaction between the neuronal and the mechanical systems. The neuromechanical simulations reveal that the currently known network is sufficient for generating a whole repertoire of swimming patterns. Swimming at different speeds and with different wavelengths, together with the performance of lateral turns can all be achieved by simply varying the brainstem input. The neuronal mechanisms behind pitch and roll manoeuvres are less clear. We have put forward a 'crossed-oscillators' hypothesis where partly separate dorsal and ventral circuits are postulated. Neuromechanical simulations of this system show that it is also capable of generating realistic pitch turns and rolls, and that vestibular signals can stabilize the posture during swimming. PMID:10382223

  13. Overuse syndromes in baseball, tennis, gymnastics, and swimming.

    PubMed

    Richardson, A B

    1983-07-01

    The shoulder is the "center of action" for most sports including those discussed in this article. Overuse problems of the shoulder are the most common group of injuries affecting the athlete involved in baseball, tennis, swimming, and gymnastics. Most of the injuries can be directly related to the mechanics of throwing, swimming, or gymnastics. After diagnosis, treatment is directed at "selective rest" of the injured shoulder and modalities and medications intended to decrease the inflammatory response of the body to stress.

  14. Establishing Zebrafish as a Novel Exercise Model: Swimming Economy, Swimming-Enhanced Growth and Muscle Growth Marker Gene Expression

    PubMed Central

    Rovira, Mireia; Brittijn, Sebastiaan A.; Burgerhout, Erik; van den Thillart, Guido E. E. J. M.; Spaink, Herman P.; Planas, Josep V.

    2010-01-01

    Background Zebrafish has been largely accepted as a vertebrate multidisciplinary model but its usefulness as a model for exercise physiology has been hampered by the scarce knowledge on its swimming economy, optimal swimming speeds and cost of transport. Therefore, we have performed individual and group-wise swimming experiments to quantify swimming economy and to demonstrate the exercise effects on growth in adult zebrafish. Methodology/Principal Findings Individual zebrafish (n = 10) were able to swim at a critical swimming speed (Ucrit) of 0.548±0.007 m s−1 or 18.0 standard body lengths (BL) s−1. The optimal swimming speed (Uopt) at which energetic efficiency is highest was 0.396±0.019 m s−1 (13.0 BL s−1) corresponding to 72.26±0.29% of Ucrit. The cost of transport at optimal swimming speed (COTopt) was 25.23±4.03 µmol g−1 m−1. A group-wise experiment was conducted with zebrafish (n = 83) swimming at Uopt for 6 h day−1 for 5 days week−1 for 4 weeks vs. zebrafish (n = 84) that rested during this period. Swimming zebrafish increased their total body length by 5.6% and body weight by 41.1% as compared to resting fish. For the first time, a highly significant exercise-induced growth is demonstrated in adult zebrafish. Expression analysis of a set of muscle growth marker genes revealed clear regulatory roles in relation to swimming-enhanced growth for genes such as growth hormone receptor b (ghrb), insulin-like growth factor 1 receptor a (igf1ra), troponin C (stnnc), slow myosin heavy chain 1 (smyhc1), troponin I2 (tnni2), myosin heavy polypeptide 2 (myhz2) and myostatin (mstnb). Conclusions/Significance From the results of our study we can conclude that zebrafish can be used as an exercise model for enhanced growth, with implications in basic, biomedical and applied sciences, such as aquaculture. PMID:21217817

  15. Reduced swim performance and aerobic capacity in adult zebrafish exposed to waterborne selenite.

    PubMed

    Massé, Anita J; Thomas, Jith K; Janz, David M

    2013-04-01

    Although dietary exposure of adult fish to organoselenium in contaminated aquatic ecosystems has been reported to bioaccumulate and cause larval deformities in offspring, subtle physiological effects produced through low level waterborne selenium exposure in fish such as swim performance and aerobic capacity have not been investigated. To evaluate potential effects of selenite on these responses, adult zebrafish (Danio rerio) were exposed to nominal aqueous concentrations of 0, 10 or 100 μg/L sodium selenite for 14 days. Upon completion of the exposure period, fish underwent two successive swim trials in a swim tunnel respirometer to determine critical swim speed (Ucrit), oxygen consumption (MO2), standard and active metabolic rates, aerobic scope (AS) and cost of transport (COT) followed by analysis of whole body triglyceride and glycogen concentrations. Selenite exposure had a significant negative effect on Ucrit and aerobic capacity. Active metabolic rates and AS significantly decreased in both selenite exposure groups after the second swim trial. No significant effect was observed in MO2, standard metabolic rate, COT, triglyceride and glycogen levels, or condition factor between groups. These results suggest that aqueous selenite exposure at environmentally relevant concentrations produces adverse effects on aerobic capacity that can diminish endurance and maximum swim speeds, which may lower fish survivability.

  16. 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..

  17. 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

  18. 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

  19. Propelling efficiency of front-crawl swimming.

    PubMed

    Toussaint, H M; Beelen, A; Rodenburg, A; Sargeant, A J; de Groot, G; Hollander, A P; van Ingen Schenau, G J

    1988-12-01

    In this study the propelling efficiency (ep) of front-crawl swimming, by use of the arms only, was calculated in four subjects. This is the ratio of the power used to overcome drag (Pd) to the total mechanical power (Po) produced including power wasted in changing the kinetic energy of masses of water (Pk). By the use of an extended version of the system to measure active drag (MAD system), Pd was measured directly. Simultaneous measurement of O2 uptake (VO2) enabled the establishment of the relationship between the rate of the energy expenditure (PVO2) and Po (since when swimming on the MAD system Po = Pd). These individual relationships describing the mechanical efficiency (8-12%) were then used to estimate Po in free swimming from measurements of VO2. Because Pd was directly measured at each velocity studied by use of the MAD system, ep could be calculated according to the equation ep = Pd/(Pd + Pk) = Pd/Po. For the four top class swimmers studied, ep was found to range from 46 to 77%. Total efficiency, defined as the product of mechanical and propelling efficiency, ranged from 5 to 8%. PMID:3215850

  20. 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

  1. Study of mechanical effects on the quality of fish feed during different stages of manufacturing.

    PubMed

    Patwary, Y A; Sarker, B S; Belal Hossain, M; Minar, M H; Shamsuddin, M

    2013-09-01

    Successful aquaculture highly depends on ensuring the quality feed which mostly depends on the proper feedstuffs selection and the manufacturing process. This study was undertaken to monitor the deviation of protein level and the mechanical effects on different biofactors viz. protein, moisture, ash, crude lipid and fiber in feed during manufacture. Samples were collected at randomly and batch wise from the prominent feed industry during the production period. Samples were collected from two different production level viz. 'Final Mixer' and 'Finished Feed' and third other sample was prepared as 'Control Mixer' on the dry basis. All the samples were analyzed by using proper analytical procedure in the laboratory of fish nutrition. The percentage of protein content was 17.9 in control mixer and 18.46 in final mixer which finally decreased to 17.03% in finished feed. In control mixer ash content was 25.74 and 23.1% in final mixer which increased in finished feed to 24.68%. Lipid content increased in finished feed (6.1%) rather than the final mixer (5.95%) and the control mixer (3.75%). However, crude fiber content decreased from control mixer to finished feed thoroughly. Crude fiber content in control mixer was 7.4% which decreased to 6.86 and 6.56% in final mixer and finished feed respectively. Again a relation may be drawn between the moisture content and ash and lipid content with crude fiber. By this study it was observed quality of feed is highly influenced by quality machine.

  2. A transcriptomics-based biological framework for studying mechanisms of endocrine disruption in small fish species.

    PubMed

    Wang, Rong-Lin; Bencic, David; Villeneuve, Daniel L; Ankley, Gerald T; Lazorchak, Jim; Edwards, Stephen

    2010-07-01

    This study sought to construct a transcriptomics-based framework of signal transduction pathways, transcriptional regulatory networks, and the hypothalamic-pituitary gonadal (HPG) axis in zebrafish (Danio rerio) to facilitate formulation of specific, testable hypotheses regarding the mechanisms of endocrine disruption in fish. For the analyses involved, we used data from a total of more than 300 microarrays representing 58 conditions, which encompassed 4 tissue types from zebrafish of both genders exposed for 1 of 3 durations to 10 different test chemicals (17alpha-ethynyl estradiol, fadrozole, 17beta-trenbolone, fipronil, prochloraz, flutamide, muscimol, ketoconazole, trilostane, and vinclozolin). Differentially expressed genes were identified by one class t-tests for each condition, and those with false discovery rates of less than 40% and treatment/control ratios > or =1.3-fold were mapped to orthologous human, mouse, and rat pathways by Ingenuity Pathway Analysis to look for overrepresentation of known biological pathways. To complement the analysis of known biological pathways, the genes regulated by approximately 1800 transcription factors were inferred using the ARACNE mutual information-based algorithm. The resulting gene sets for all transcriptional factors, along with a group of compiled HPG-axis genes and approximately 130 publicly available biological pathways, were analyzed for their responses to the 58 treatment conditions by Gene Set Enrichment Analysis (GSEA) and its variant, Extended-GSEA. The biological pathways and transcription factors associated with multiple distinct treatments showed substantial interactions among the HPG-axis, TGF-beta, p53, and several of their cross-talking partners. These candidate networks/pathways have a variety of profound impacts on such cellular functions as stress response, cell cycle, and apoptosis.

  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.

  4. Nonhepatic origin of notothenioid antifreeze reveals pancreatic synthesis as common mechanism in polar fish freezing avoidance

    PubMed Central

    Cheng, Chi-Hing C.; Cziko, Paul A.; Evans, Clive W.

    2006-01-01

    Phylogenetically diverse polar and subpolar marine teleost fishes have evolved antifreeze proteins (AFPs) or antifreeze glycoproteins (AFGPs) to avoid inoculative freezing by internalized ice. For over three decades since the first fish antifreeze (AF) protein was discovered, many studies of teleost freezing avoidance showed hepatic AF synthesis and distribution within the circulation as pivotal in preventing the blood, and therefore the fish, from freezing. We have uncovered an important twist to this long-held paradigm: the complete absence of liver synthesis of AFGPs in any life stage of the Antarctic notothenioids, indicating that the liver plays no role in the freezing avoidance in these fishes. Instead, we found the exocrine pancreas to be the major site of AFGP synthesis and secretion in all life stages, and that pancreatic AFGPs enter the intestinal lumen via the pancreatic duct to prevent ingested ice from nucleating the hyposmotic intestinal fluids. AFGPs appear to remain undegraded in the intestinal milieu, and the composition and relative abundance of intestinal AFGP isoforms are nearly identical to serum AFGPs. Thus, the reabsorption of intact pancreas-derived intestinal AFGPs, and not the liver, is the likely source of circulatory AFGPs in notothenioid fishes. We examined diverse northern fish taxa and Antarctic eelpouts with hepatic synthesis of bloodborne AF and found that they also express secreted pancreatic AF of their respective types. The evolutionary convergence of this functional physiology underscores the hitherto largely unrecognized importance of intestinal freezing prevention in polar teleost freezing avoidance, especially in the chronically icy Antarctic waters. PMID:16798878

  5. 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.

  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.

  7. 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.

  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 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

  9. 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

  10. 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.

  11. Ecotoxicological effects of waterborne PFOS exposure on swimming performance and energy expenditure in juvenile goldfish (Carassius auratus).

    PubMed

    Xia, Jigang; Fu, Shijian; Cao, Zhendong; Peng, Jianglan; Peng, Jing; Dai, Tingting; Cheng, Lili

    2013-08-01

    The potential risks of perfluorooctane sulfonate (PFOS) are of increasing ecological concern. Swimming performance is linked to the fitness and health of fish. However, the impacts of PFOS on swimming performance remain largely unknown. We investigated the ecotoxicological effects of acute exposure to PFOS on the swimming performance and energy expenditure of juvenile goldfish (Carassius auratus). The fish were exposed to a range of PFOS concentrations (0, 0.5, 2, 8 and 32 mg/L) for 48 hr. The spontaneous swimming activity, fast-start swimming performance, critical swimming speed (U(crit)) and active metabolic rate (AMR) of the goldfish were examined after exposure to PFOS. PFOS exposure resulted in remarkable effects on spontaneous activity. Motion distance was reduced, and the proportion of motionless time increased with increasing concentrations of PFOS. However, no significant alterations in the fast-start performance-related kinematic parameters, such as latency time, maximum linear velocity, maximum linear acceleration or escape distance during the first 120 msec after stimulus, were observed after PFOS exposure. Unexpectedly, although PFOS exposure had marked influences on the swimming oxygen consumption rates and AMR of goldfish, the U(crit) of the goldfish was not significantly affected by PFOS. This may result in a noteworthy increase in the energetic cost of transport. The overall results indicate that, in contrast to spontaneous activity, underlying swimming capabilities are maintained in goldfish after short-term exposure to PFOS, but energy expenditure during the process of swimming is dramatically aggravated. PMID:24520707

  12. 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

  13. Ecotoxicological effects of waterborne PFOS exposure on swimming performance and energy expenditure in juvenile goldfish (Carassius auratus).

    PubMed

    Xia, Jigang; Fu, Shijian; Cao, Zhendong; Peng, Jianglan; Peng, Jing; Dai, Tingting; Cheng, Lili

    2013-08-01

    The potential risks of perfluorooctane sulfonate (PFOS) are of increasing ecological concern. Swimming performance is linked to the fitness and health of fish. However, the impacts of PFOS on swimming performance remain largely unknown. We investigated the ecotoxicological effects of acute exposure to PFOS on the swimming performance and energy expenditure of juvenile goldfish (Carassius auratus). The fish were exposed to a range of PFOS concentrations (0, 0.5, 2, 8 and 32 mg/L) for 48 hr. The spontaneous swimming activity, fast-start swimming performance, critical swimming speed (U(crit)) and active metabolic rate (AMR) of the goldfish were examined after exposure to PFOS. PFOS exposure resulted in remarkable effects on spontaneous activity. Motion distance was reduced, and the proportion of motionless time increased with increasing concentrations of PFOS. However, no significant alterations in the fast-start performance-related kinematic parameters, such as latency time, maximum linear velocity, maximum linear acceleration or escape distance during the first 120 msec after stimulus, were observed after PFOS exposure. Unexpectedly, although PFOS exposure had marked influences on the swimming oxygen consumption rates and AMR of goldfish, the U(crit) of the goldfish was not significantly affected by PFOS. This may result in a noteworthy increase in the energetic cost of transport. The overall results indicate that, in contrast to spontaneous activity, underlying swimming capabilities are maintained in goldfish after short-term exposure to PFOS, but energy expenditure during the process of swimming is dramatically aggravated.

  14. 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.

  15. 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

  16. 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

  17. 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

  18. Acute embryonic or juvenile exposure to Deepwater Horizon crude oil impairs the swimming performance of mahi-mahi (Coryphaena hippurus).

    PubMed

    Mager, Edward M; Esbaugh, Andrew J; Stieglitz, John D; Hoenig, Ronald; Bodinier, Charlotte; Incardona, John P; Scholz, Nathaniel L; Benetti, Daniel D; Grosell, Martin

    2014-06-17

    The Deepwater Horizon incident likely resulted in exposure of commercially and ecologically important fish species to crude oil during the sensitive early life stages. We show that brief exposure of a water-accommodated fraction of oil from the spill to mahi-mahi as juveniles, or as embryos/larvae that were then raised for ∼25 days to juveniles, reduces their swimming performance. These physiological deficits, likely attributable to polycyclic aromatic hydrocarbons (PAHs), occurred at environmentally realistic exposure concentrations. Specifically, a 48 h exposure of 1.2 ± 0.6 μg L(-1) ΣPAHs (geometric mean ± SEM) to embryos/larvae that were then raised to juvenile stage or a 24 h exposure of 30 ± 7 μg L(-1) ΣPAHs (geometric mean ± SEM) directly to juveniles resulted in 37% and 22% decreases in critical swimming velocities (Ucrit), respectively. Oil-exposed larvae from the 48 h exposure showed a 4.5-fold increase in the incidence of pericardial and yolk sac edema relative to controls. However, this larval cardiotoxicity did not manifest in a reduced aerobic scope in the surviving juveniles. Instead, respirometric analyses point to a reduction in swimming efficiency as a potential alternative or contributing mechanism for the observed decreases in Ucrit. PMID:24857158

  19. 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.

  20. 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…

  1. 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...

  2. 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...

  3. 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

  4. 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.

  5. On numerical modeling of animal swimming and flight

    NASA Astrophysics Data System (ADS)

    Deng, Hong-Bin; Xu, Yuan-Qing; Chen, Duan-Duan; Dai, Hu; Wu, Jian; Tian, Fang-Bao

    2013-12-01

    Aquatic and aerial animals have developed their superior and complete mechanisms of swimming and flight. These mechanisms bring excellent locomotion performances to natural creatures, including high efficiency, long endurance ability, high maneuverability and low noise, and can potentially provide inspiration for the design of the man-made vehicles. As an efficient research approach, numerical modeling becomes more and more important in studying the mechanisms of swimming and flight. This review is focused on assessing the recent progress in numerical techniques of solving animal swimming and flight problems. According to the complexity of the problems considered, numerical studies are classified into five stages, of which the main characteristics and the numerical strategies are described and discussed. In addition, the body-conformal mesh, Cartesian-mesh, overset-grid, and meshfree methods are briefly introduced. Finally, several open issues in numerical modeling in this field are highlighted.

  6. 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

  7. 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

  8. Intermittent cold water swim stress increases immobility and interferes with escape performance in rat.

    PubMed

    Christianson, John P; Drugan, Robert C

    2005-11-30

    The behavioral consequences of intermittent, 5 s cold-water swims (15 degrees C) or confinement were assessed 24 h after stress in a 5 min forced swim test or an instrumental swim escape test (SET). The SET was conducted with temporal and instrumental parameters similar to the shock-motivated shuttle escape test. The tests detected significantly increased immobility in the forced swim test and increased latency to escape in the SET. These results extend previous findings with intermittent swim stress and provide evidence that intermittent swim stress produces behavioral deficits similar to other stress models. This new model may be a useful tool for exploring the physiological mechanisms underlying the stress response.

  9. 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.

  10. 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

  11. 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

  12. 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.

  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. 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 ...

  15. The cost of swimming in generalized Newtonian fluids: experiments with C. elegans

    NASA Astrophysics Data System (ADS)

    Gagnon, D. A.; Arratia, P. E.

    2016-08-01

    Numerous natural processes are contingent on microorganisms' ability to swim through fluids with non-Newtonian rheology. Here, we use the model organism Caenorhabditis elegans and tracking methods to experimentally investigate the dynamics of undulatory swimming in shear-thinning fluids. Theory and simulation have proposed that the cost of swimming, or mechanical power, should be lower in a shear-thinning fluid compared to a Newtonian fluid of the same zero-shear viscosity. We aim to provide an experimental investigation into the cost of swimming in a shear-thinning fluid from (i) an estimate of the mechanical power of the swimmer and (ii) the viscous dissipation rate of the flow field, which should yield equivalent results for a self-propelled low Reynolds number swimmer. We find the cost of swimming in shear-thinning fluids is less than or equal to the cost of swimming in Newtonian fluids of the same zero-shear viscosity; furthermore, the cost of swimming in shear-thinning fluids scales with a fluid's effective viscosity and can be predicted using fluid rheology and simple swimming kinematics. Our results agree reasonably well with previous theoretical predictions and provide a framework for understanding the cost of swimming in generalized Newtonian fluids.

  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

    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.

  17. 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.

  18. Intersex in fishes and amphibians: population implications, prevalence, mechanisms and molecular biomarkers.

    PubMed

    Abdel-Moneim, Ahmed; Coulter, David P; Mahapatra, Cecon T; Sepúlveda, Maria S

    2015-11-01

    Intersex is defined as the abnormal presence of both testicular and ovarian cells in gonads of gonochoristic animals. Its occurrence is widespread and reports on its presence in the gonads of vertebrates continues to increase. In this review, we use standardized terminology to summarize the current knowledge of intersex in gonochoristic fishes and amphibians. We describe the different indices that have been used to assess the severity of intersex and synthesize reports discussing the prevalence of intersex in relation to different types of pollutants. In addition, we evaluate the geographic distribution and chronology of the reported cases of intersex in fishes and amphibians, their pathological descriptions and severity and discuss species sensitivities. We also summarize molecular biomarkers that have been tested for early detection of intersex in wild populations and highlight additional biomarkers that target molecular pathways involved in gonadal development that require further investigation for use in the diagnosis of intersex. Finally, we discuss the needs for future research in this field.

  19. In vitro studies of acute toxicity mechanisms and structure-activity relationships of nonionic surfactants in fish

    SciTech Connect

    Bodishbauah, D.F.

    1994-12-31

    In fish, gills are believed to be a primary target for a number of toxicants. Gills perform the essential systemic functions of gas exchange, waste elimination, and ion/pH balance, and are exposed to ambient environmental toxicant levels. Qualitative gill morphology changes are easily observed, but quantitative measures of impaired function are difficult. This in vitro technique utilizes the opercular epithelium of the mummichog, Fundulus heteroclitus, as a surrogate for gill epithelium in mechanistic toxicity and structure-activity studies. This model has long been used by electrophysiologists studying osmoregulation in marine fish. Effects on trans-epithelial potential (TEP) and/or short-circuit current (I{sub sc}) across the opercular epithelium can be made for any pollutant of interest, using an epithelial voltage clamp and Ussing chamber. The nonionic synthetic surfactant class, alkylphenol ethoxylates, were chosen as a model toxicant class to test this experimental model. Synthetic surfactants are ubiquitous waterborne pollutants, with annual North American usage approaching eight billion pounds. Surfactants are recognized as potent, acute gill toxicants in fish. The exact mechanism of toxicity has yet to be elucidated. These compounds proved to be potent inhibitors of both TEP and I{sub sc} in vitro, at dose levels comparable to those causing lethality, suggesting that impaired osmoregulation plays a role in their acute toxicity. Similar structure-activity relationships were found for the endpoints of acute lethality to F. heteroclitus and impaired in vitro epithelial transport.

  20. 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

  1. 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.

  2. Unsteady Laminar CFD Simulation of Undulatory Rainbow Trout Swimming Hydrodynamics

    NASA Astrophysics Data System (ADS)

    Flanagan, Patrick; Hotchkiss, Rollin; Stock, David

    2004-11-01

    The propulsion mechanism of an undulatory swimming 10 cm rainbow trout (oncorhynchus mykiss) is studied using a laminar 2-D unsteady incompressible Navier-Stokes computational model with a moving adaptive mesh (Fluent 6.1). The wake mechanism is dominated by a reverse von Karman vortex street and compares well to previous experimental data. Thrust and drag forces are quantified and the equilibrium condition is satisfied within 5%. A method is developed to calculate hydrodynamic power using work, which results in a swimming efficiency of 62%. An investigation of the boundary layer shows incipient separation and highly unsteady velocity profiles.

  3. Relationships among traits of aerobic and anaerobic swimming performance in individual European sea bass Dicentrarchus labrax.

    PubMed

    Marras, Stefano; Killen, Shaun S; Domenici, Paolo; Claireaux, Guy; McKenzie, David J

    2013-01-01

    Teleost fishes exhibit wide and temporally stable inter-individual variation in a suite of aerobic and anaerobic locomotor traits. One mechanism that could allow such variation to persist within populations is the presence of tradeoffs between aerobic and anaerobic performance, such that individuals with a high capacity for one type of performance have a reduced capacity for the other. We investigated this possibility in European seabass Dicentrarchuslabrax, each measured for a battery of indicators of maximum locomotor performance. Aerobic traits comprised active metabolic rate, aerobic scope for activity, maximum aerobic swimming speed, and stride length, using a constant acceleration test. Anaerobic traits comprised maximum speed during an escape response, maximum sprint speed, and maximum anaerobic burst speed during constant acceleration. The data provided evidence of significant variation in performance among individuals, but there was no evidence of any trade-offs among any traits of aerobic versus anaerobic swimming performance. Furthermore, the anaerobic traits were not correlated significantly among each other, despite relying on the same muscular structures. Thus, the variation observed may reflect trade-offs with other morphological, physiological or behavioural traits.

  4. Relationships among Traits of Aerobic and Anaerobic Swimming Performance in Individual European Sea Bass Dicentrarchus labrax

    PubMed Central

    Marras, Stefano; Killen, Shaun S.; Domenici, Paolo; Claireaux, Guy; McKenzie, David J.

    2013-01-01

    Teleost fishes exhibit wide and temporally stable inter-individual variation in a suite of aerobic and anaerobic locomotor traits. One mechanism that could allow such variation to persist within populations is the presence of tradeoffs between aerobic and anaerobic performance, such that individuals with a high capacity for one type of performance have a reduced capacity for the other. We investigated this possibility in European seabass Dicentrarchuslabrax, each measured for a battery of indicators of maximum locomotor performance. Aerobic traits comprised active metabolic rate, aerobic scope for activity, maximum aerobic swimming speed, and stride length, using a constant acceleration test. Anaerobic traits comprised maximum speed during an escape response, maximum sprint speed, and maximum anaerobic burst speed during constant acceleration. The data provided evidence of significant variation in performance among individuals, but there was no evidence of any trade-offs among any traits of aerobic versus anaerobic swimming performance. Furthermore, the anaerobic traits were not correlated significantly among each other, despite relying on the same muscular structures. Thus, the variation observed may reflect trade-offs with other morphological, physiological or behavioural traits. PMID:24019879

  5. 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.

  6. 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

  7. Hydrodynamics and energy-saving swimming techniques of Pacific bluefin tuna.

    PubMed

    Takagi, Tsutomu; Tamura, Yumiko; Weihs, Daniel

    2013-11-01

    Weihs theoretically revealed that during the movement of fish with negative buoyancy, more kinetic energy is saved in the glide and upward (GAU) swimming mode than in the continuous horizontal swimming mode. Because kinetic energy saving depends on dynamic parameters such as the drag and lift of the body, the effects of variations in these parameters on energy saving for different species remain unknown. Here, the kinetic energy saving of Pacific bluefin tuna (PBT), Thunnus orientalis, exhibiting the GAU swimming mode was investigated. The dynamic properties of PBT were estimated by carrying out CFD analysis. The CFD model was produced by using a three-dimensional laser surface profiler, and the model was controlled such that it exhibited swimming motion similar to that of a live PBT swimming in a flume tank. The drag generated by tail beating, which significantly affects the kinetic energy during motion, was twice that generated in the glide mode. The faster the upward swimming speed, the lesser is the kinetic energy saving; therefore, when the upward swimming speed is more than twice the glide speed, there is no gain in the GAU mode. However, when SMR (Standard Metabolic Rate) is considered, if the energy based on SMR is assumed to be 30% of the total energy spent during motion, the most efficient upward swimming speed is 1.4 times the glide speed. The GAU swimming mode of PBT leads to energy saving during motion, and the upward swimming speed and the lift force produced by the pectoral fins for the most efficient drive are unique for different species of different sizes.

  8. Readaptation of fish to 1g after long-term microgravity: behavioural results from the STS 89 mission.

    PubMed

    Anken, R H; Hilbig, R; Ibsch, M; Rahmann, H

    2000-01-01

    The swimming behaviour of adult and neonate swordtail fish Xiphophorus helleri was qualitatively analysed from video recordings taken throughout the STS 89 spaceshuttle mission from launch to landing and thereafter. After the flight, the swimming behaviour of neonate samples was quantitatively assessed in the course of the readaptation to 1g earth gravity at days 0, 1 and 4 after recovery. Regarding the swimming behaviour during the mission, the adult fish swam thigmotactically (i.e., responding to tactile stimuli) along the walls of their aquarium, but like the neonates, they did not show any aberrant behavioural patterns. This indicates that they could easily adapt themselves to microgravity. On mission day 9, however, looping responses (most probably initiated by mechanical disturbances) occurred indicating a continuously performed "C-start" escape response (the respective body bend looks like the letter "C"). Immediately after landing (observed in videos recorded onboard the space shuttle), the adults performed a head-up swimming beating heavily with the caudal and pectoral fins; this aberrant behaviour gradually decreased during the first hours after recovery.

  9. 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

  10. 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.

  11. 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

  12. Aerobic swimming performance of juvenile largemouth bronze gudgeon (Coreius guichenoti) in the Yangtze River.

    PubMed

    Tu, Zhiying; Li, Liping; Yuan, Xi; Huang, Yingping; Johnson, David

    2012-06-01

    Largemouth bronze gudgeon (Coreius guichenoti), a fish species once abundant in the Yangtze River, has been rapidly declining in recent years. One important factor, among many, is the interruption of the free-flowing rivers by dams. To obtain data that can be applied to the design of an effective fishway for C. guichenoti and other species in the fish community, a laboratory study of juvenile C. guichenoti's swimming ability and energetics was conducted in a flume-type respirometer equipped with a high-speed video camera system to record swimming behavior. The critical swimming speed (Ucrit ), standard metabolic rate (SMR), and maximum metabolic rate (MO2,max ) were determined during steady swimming at four water temperatures (10, 15, 20, and 25°C). A power function accurately describes the relationship between oxygen consumption rate (MO2 ) and swimming speed (U) at the four temperatures. The Ucrit , SMR, MO2,max , and metabolic scope increased with increasing temperature. The relationship between cost of transport (COT) and U was characteristically inverse bell-shaped, with minimum COT at Uopt = 4.5-5.0 body lengths per second (bl sec(-1)). This investigation provides data on the swimming ability of C. guichenoti that will add to the basic science required for fishway design.

  13. The Impact of Immediate Verbal Feedback on the Improvement of Swimming Technique

    PubMed Central

    Zatoń, Krystyna; Szczepan, Stefan

    2014-01-01

    The present research attempts to ascertain the impact of immediate verbal feedback (IVF) on modifications of stroke length (SL). In all swimming styles, stroke length is considered an essential kinematic parameter of the swimming cycle. It is important for swimming mechanics and energetics. If SL shortens while the stroke rate (SR) remains unchanged or decreases, the temporal-spatial structure of swimming is considered erroneous. It results in a lower swimming velocity. Our research included 64 subjects, who were divided into two groups: the experimental – E (n=32) and the control – C (n=32) groups. A pretest and a post-test were conducted. The subjects swam the front crawl over the test distance of 25m at Vmax. Only the E group subjects were provided with IVF aiming to increase their SL. All tests were filmed by two cameras (50 samples•s-1). The kinematic parameters of the swimming cycle were analyzed using the SIMI Reality Motion Systems 2D software (SIMI Reality Motion Systems 2D GmbH, Germany). The movement analysis allowed to determine the average horizontal swimming velocity over 15 meters. The repeated measures analysis of variance ANOVA with a post-hoc Tukey range test demonstrated statistically significant (p<0.05) differences between the two groups in terms of SL and swimming velocity. IVF brought about a 6.93% (Simi method) and a 5.09% (Hay method) increase in SL, as well as a 2.92% increase in swimming velocity. PMID:25114741

  14. Development of gel materials with high transparency and mechanical strength for use with a 3D gel printer SWIM-ER

    NASA Astrophysics Data System (ADS)

    Tase, Taishi; Okada, Koji; Takamatsu, Kyuichiro; Saito, Azusa; Kawakami, Masaru; Furukawa, Hidemitsu

    2016-04-01

    Medical doctors use artificial blood vessels and organ models, which are usually made of plastic, to explain operations to students, or patients awaiting treatment. However, there are some problems such as the high cost of making the model and there is not a realistic feel because the model is hard. These problems can be solved using soft and wet material for instance gel. Gels are materials with unique properties such as transparency, biocompatibility, and low friction. In recent years, high strength gel has been developed and is expected to be applied in medical fields in the future. Artificial models of gel can be produced by 3D gel printers. Our group has been developing a 3D gel printer with 1mm precision in printing, but the shape, size and mechanical strength are not sufficient for medical models. In this study, we overcome these problems and make a gel model which is transparent, mechanically strong with a fine shape. The strength and molding accuracy is improved by changing and preparing the cross linker and ultraviolet absorber. We conducted mechanical and molding tests to confirm that the gel material properties improved.

  15. 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

  16. 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.

  17. Intersex in fishes and amphibians: population implications, prevalence, mechanisms and molecular biomarkers.

    PubMed

    Abdel-Moneim, Ahmed; Coulter, David P; Mahapatra, Cecon T; Sepúlveda, Maria S

    2015-11-01

    Intersex is defined as the abnormal presence of both testicular and ovarian cells in gonads of gonochoristic animals. Its occurrence is widespread and reports on its presence in the gonads of vertebrates continues to increase. In this review, we use standardized terminology to summarize the current knowledge of intersex in gonochoristic fishes and amphibians. We describe the different indices that have been used to assess the severity of intersex and synthesize reports discussing the prevalence of intersex in relation to different types of pollutants. In addition, we evaluate the geographic distribution and chronology of the reported cases of intersex in fishes and amphibians, their pathological descriptions and severity and discuss species sensitivities. We also summarize molecular biomarkers that have been tested for early detection of intersex in wild populations and highlight additional biomarkers that target molecular pathways involved in gonadal development that require further investigation for use in the diagnosis of intersex. Finally, we discuss the needs for future research in this field. PMID:26211897

  18. 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

  19. 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

  20. Swim stress differentially blocks CRF receptor mediated responses in dorsal raphe nucleus.

    PubMed

    Lamy, Christophe M; Beck, Sheryl G

    2010-10-01

    Modulation of the serotonergic (5-HT) neurotransmitter system arising from the dorsal raphe nucleus (DR) is thought to support the behavioral effects of swim stress, i.e., immobility. In vivo pharmacological and anatomical studies suggest that corticotropin-releasing factor (CRF) and γ-aminobutyric acid (GABA) synaptic transmission closely interact to set the response of the DR to swim stress. To investigate the cellular basis of these physiological mechanisms the effects of ovine CRF (oCRF) on GABA(A)-dependent miniature inhibitory postsynaptic currents (mIPSCs) in 5-HT and non-5-HT DR neurons in acute mesencephalic slices obtained from rats either naïve or 24h after a 15 min swim stress session were tested. In this study, the effect of swim stress alone was to decrease the holding current, i.e., hyperpolarize the neuron, and to increase the amplitude and charge of mIPSCs recorded from non-5-HT neurons. Ovine CRF (10 nM) induced an increase in mIPSC frequency in 5-HT neurons recorded from naïve rats, an effect that was suppressed by swim stress. The inward current elicited by oCRF in both 5-HT and non-5-HT neurons was also blocked by swim stress. Ovine CRF increased mIPSCs amplitude and charge in both 5-HT and non-5-HT neurons, but this effect was not modified by swim stress. In concert with our previous findings that swim stress decreased input resistance, action potential threshold and action potential duration and increased glutamatergic synaptic activity the overall primary effect of swim stress is to increase the excitability of 5-HT neurons. These data provide a mechanism at the cellular level for the immobility induced by swim stress and identifies critical components of the raphe circuitry responsible for the altered output of 5-HT neurons induced by swim stress.

  1. A new system for analyzing swim fin propulsion based on human kinematic data.

    PubMed

    Nicolas, Guillaume; Bideau, Benoit; Bideau, Nicolas; Colobert, Briac; Le Guerroue, Gaël; Delamarche, Paul

    2010-07-20

    The use of swim fins has become popular in various water sport activities. While numerous models of swim fin with various innovative shapes have been subjectively designed, the exact influence of the fin characteristics on swimming performance is still much debated, and remains difficult to quantify. To date, the most common approach for evaluating swim fin propulsion is based on the study of "swimmer-fins" as a global system, where physiological and/or biomechanical responses are considered. However, reproducible swimming technique is difficult (or even impossible) to obtain on human body and may lead to discrepancies in data acquired between trials. In this study, we present and validate a new automat called HERMES which enables an evaluation of various swim fins during an adjustable, standardized and reproducible motion. This test bench reliably and accurately reproduces human fin-swimming motions, and gives resulting dynamic measurements at the ankle joint. Seven fins with various geometrical and mechanical characteristics were tested. For each swim fin, ankle force and hydromechanical efficiency (useful mechanical power output divided by mechanical power input delivered by the motors) were calculated. Efficiencies reported in our study were high (close to 70% for some swim fins) over a narrow range of Strouhal number (St) and peaks within the interval 0.2swimming animals. Therefore, an interesting prospect in this work would be to accurately study the impact of adjustable fin kinematics and material (design and mechanical properties) on the wake structure and on efficiency.

  2. 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

  3. Effects of quinine on the mechanical frequency response of the cupula in the fish lateral line.

    PubMed

    van Netten, S M; Karlsson, K K; Khanna, S M; Flock, A

    1994-03-01

    Quinine induces changes in the motion of the cupula in the lateral line canal of the African knife-fish in response to sinusoidal water movements. Two different phases in the action of quinine on the cupular frequency response can be discerned. In the first phase the best frequency, i.e., the frequency at which the cupular vibratory displacement is maximal in response to constant-amplitude sinusoidal canal fluid displacement, shifts toward higher frequencies. During this phase, lasting about 70-100 min, the best frequency increases by a factor between 1.3 and 1.5. In the second phase, during roughly the following 90 min, the best frequency decreases gradually to a value 0.3-0.5 times that observed before the application of quinine.

  4. Facing warm temperatures during migration: cardiac mRNA responses of two adult Oncorhynchus nerka populations to warming and swimming challenges.

    PubMed

    Anttila, K; Eliason, E J; Kaukinen, K H; Miller, K M; Farrell, A P

    2014-05-01

    The main findings of the current study were that exposing adult sockeye salmon Onchorhynchus nerka to a warm temperature that they regularly encounter during their river migration induced a heat shock response at an mRNA level, and this response was exacerbated with forced swimming. Similar to the heat shock response, increased immune defence-related responses were also observed after warm temperature treatment and with a swimming challenge in two different populations (Chilko and Nechako), but with some important differences. Microarray analyses revealed that 347 genes were differentially expressed between the cold (12-13° C) and warm (18-19° C) treated fish, with stress response (GO:0006950) and response to fungus (GO:0009620) elevated with warm treatment, while expression for genes involved in oxidative phosphorylation (GO:0006119) and electron transport chain (GO:0022900) elevated for cold-treated fish. Analysis of single genes with real-time quantitative PCR revealed that temperature had the most significant effect on mRNA expression levels, with swimming and population having secondary influences. Warm temperature treatment for the Chilko population induced expression of heat shock protein (hsp) 90α, hsp90β and hsp30 as well as interferon-inducible protein. The Nechako population, which is known to have a narrower thermal tolerance window than the Chilko population, showed even more pronounced stress responses to the warm treatment and there was significant interaction between population and temperature treatment for hsp90β expression. Moreover, significant interactions were noted between temperature treatment and swimming challenge for hsp90α and hsp30, and while swimming challenge alone increased expression of these hsps, the expression levels were significantly elevated in warm-treated fish swum to exhaustion. In conclusion, it seems that adult O. nerka currently encounter conditions that induce several cellular defence mechanisms during their once

  5. Optimal swimming of a sheet.

    PubMed

    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. PMID:25019709

  6. 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.

  7. The Mouse Forced Swim Test

    PubMed Central

    Can, Adem; Dao, David T.; Arad, Michal; Terrillion, Chantelle E.; Piantadosi, Sean C.; Gould, Todd D.

    2012-01-01

    The forced swim test is a rodent behavioral test used for evaluation of antidepressant drugs, antidepressant efficacy of new compounds, and experimental manipulations that are aimed at rendering or preventing depressive-like states. Mice are placed in an inescapable transparent tank that is filled with water and their escape related mobility behavior is measured. The forced swim test is straightforward to conduct reliably and it requires minimal specialized equipment. Successful implementation of the forced swim test requires adherence to certain procedural details and minimization of unwarranted stress to the mice. In the protocol description and the accompanying video, we explain how to conduct the mouse version of this test with emphasis on potential pitfalls that may be detrimental to interpretation of results and how to avoid them. Additionally, we explain how the behaviors manifested in the test are assessed. PMID:22314943

  8. 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.

  9. The mouse forced swim test.

    PubMed

    Can, Adem; Dao, David T; Arad, Michal; Terrillion, Chantelle E; Piantadosi, Sean C; Gould, Todd D

    2012-01-29

    The forced swim test is a rodent behavioral test used for evaluation of antidepressant drugs, antidepressant efficacy of new compounds, and experimental manipulations that are aimed at rendering or preventing depressive-like states. Mice are placed in an inescapable transparent tank that is filled with water and their escape related mobility behavior is measured. The forced swim test is straightforward to conduct reliably and it requires minimal specialized equipment. Successful implementation of the forced swim test requires adherence to certain procedural details and minimization of unwarranted stress to the mice. In the protocol description and the accompanying video, we explain how to conduct the mouse version of this test with emphasis on potential pitfalls that may be detrimental to interpretation of results and how to avoid them. Additionally, we explain how the behaviors manifested in the test are assessed.

  10. Movement and function of the pectoral fins of the larval zebrafish (Danio rerio) during slow swimming.

    PubMed

    Green, Matthew H; Ho, Robert K; Hale, Melina E

    2011-09-15

    Pectoral fins are known to play important roles in swimming for many adult fish; however, their functions in fish larvae are unclear. We examined routine pectoral fin movement during rhythmic forward swimming and used genetic ablation to test hypotheses of fin function in larval zebrafish. Fins were active throughout bouts of slow swimming. Initiation was characterized by asymmetric fin abduction that transitioned to alternating rhythmic movement with first fin adduction. During subsequent swimming, fin beat amplitude decreased while tail beat amplitude increased over swimming speeds ranging from 1.47 to 4.56 body lengths per second. There was no change in fin or tail beat frequency with speed (means ± s.d.: 28.2±3.5 and 29.6±1.9 Hz, respectively). To examine potential roles of the pectoral fins in swimming, we compared the kinematics of finless larvae generated with a morpholino knockdown of the gene fgf24 to those of normal fish. Pectoral fins were not required for initiation nor did they significantly impact forward rhythmic swimming. We investigated an alternative hypothesis that the fins function in respiration. Dye visualization demonstrated that pectoral fin beats bring distant fluid toward the body and move it caudally behind the fins, disrupting the boundary layer along the body's surface, a major site of oxygen absorption in larvae. Larval zebrafish also demonstrated more fin beating in low oxygen conditions. Our data reject the hypothesis that the pectoral fins of larval zebrafish have a locomotor function during slow, forward locomotion, but are consistent with the hypothesis that the fins have a respiratory function.

  11. Swimming with stiff legs at low Reynolds number.

    PubMed

    Takagi, Daisuke

    2015-08-01

    Locomotion at low Reynolds number is not possible with cycles of reciprocal motion, an example being the oscillation of a single pair of rigid paddles or legs. Here, I demonstrate the possibility of swimming with two or more pairs of legs. They are assumed to oscillate collectively in a metachronal wave pattern in a minimal model based on slender-body theory for Stokes flow. The model predicts locomotion in the direction of the traveling wave, as commonly observed along the body of free-swimming crustaceans. The displacement of the body and the swimming efficiency depend on the number of legs, the amplitude, and the phase of oscillations. This study shows that paddling legs with distinct orientations and phases offers a simple mechanism for driving flow.

  12. 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.

  13. 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

  14. Unsteady low-Re swimming

    NASA Astrophysics Data System (ADS)

    Pak, On Shun; Lauga, Eric

    2009-11-01

    In this talk, we focus on unsteady effects relevant to the fluid-based locomotion of micro-organisms. First, we consider transient effects in locomotion arising from the inertia of both the swimmer and the surrounding fluid. We discuss and derive the relevant time scales governing transient effects in low Reynolds number swimming, and illustrate them using the prototypical problem of a 2D swimmer starting from rest. Second, we address geometrical unsteadiness resulting from the finite-size of the swimmer. We solve numerically for the swimming kinematics of active (internally-forced) filaments, as models for eukaryotic flagella, and discuss the resulting unsteadiness of the cell body.

  15. 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

  16. 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

  17. Low Reynolds Number Swimming in Two Dimensions

    NASA Astrophysics Data System (ADS)

    Cherman, Alexandre; Delgado, Joaquín; Duda, Fernando; Ehlers, Kurt; Koiller, Jair; Montgomery, Richard

    2000-10-01

    A geometrical approach for low Reynolds number swimming was introduced by Shapere and Wilczek1. Here we pursue some developments for the two dimensional theory. The outer membrane or the ciliary envelope of the planar organism is represented by the conformal image of the unit circle. Power expenditures and velocities can be computed using complex variable techniques. As an example, we present the calculations for a self deforming ellipse. The results compare well with observations for the nematode Turbatrix aceti. We also compute the most efficient swimming stroke, using the criterion efficiency = velocity/hydrodynamical power. A pattern noticed by SW for the circle and the sphere is confirmed: efficiency is optimized around certain high order geometric modes. For the case of a deforming membrane, these modes require great mechanical stress. However, such high order geometric modes are easily emulated by ciliary envelopes without extra (mechanical) power expenditure. Therefore, coordinated spatio-temporal ciliary movements, besides providing an inherent maneuverability, have the added advantage of saving energy.

  18. Effect of temperature on maximum swimming speed and cost of transport in juvenile European sea bass (Dicentrarchus labrax).

    PubMed

    Claireaux, Guy; Couturier, Christine; Groison, Anne-Laure

    2006-09-01

    This study is an attempt to gain an integrated understanding of the interactions between temperature, locomotion activity and metabolism in the European sea bass (Dicentrarchus labrax). To our knowledge this study is among the few that have investigated the influence of the seasonal changes in water temperature on swimming performance in fish. Using a Brett-type swim-tunnel respirometer the relationship between oxygen consumption and swimming speed was determined in fish acclimatised to 7, 11, 14, 18, 22, 26 and 30 degrees C. The corresponding maximum swimming speed (U(max)), optimal swimming speed (U(opt)), active (AMR) and standard (SMR) metabolic rates as well as aerobic metabolic scope (MS) were calculated. Using simple mathematical functions, these parameters were modelled as a function of water temperature and swimming speed. Both SMR and AMR were positively related to water temperature up to 24 degrees C. Above 24 degrees C SMR and AMR levelled off and MS tended to decrease. We found a tight relationship between AMR and U(max) and observed that raising the temperature increased AMR and increased swimming ability. However, although fish swam faster at high temperature, the net cost of transport (COT(net)) at a given speed was not influence by the elevation of the water temperature. Although U(opt) doubled between 7 degrees C and 30 degrees C (from 0.3 to 0.6 m s(-1)), metabolic rate at U(opt) represented a relatively constant fraction of the animal active metabolic rate (40-45%). A proposed model integrates the effects of water temperature on the interaction between metabolism and swimming performance. In particular the controlling effect of temperature on AMR is shown to be the key factor limiting maximal swimming speed of sea bass.

  19. 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…

  20. 36 CFR 327.5 - Swimming.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 3 2011-07-01 2011-07-01 false Swimming. 327.5 Section 327.5 Parks, Forests, and Public Property CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY RULES AND REGULATIONS... Swimming. (a) Swimming, wading, snorkeling or scuba diving at one's own risk is permitted, except...

  1. 36 CFR 327.5 - Swimming.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Swimming. 327.5 Section 327.5 Parks, Forests, and Public Property CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY RULES AND REGULATIONS... Swimming. (a) Swimming, wading, snorkeling or scuba diving at one's own risk is permitted, except...

  2. 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…

  3. An Open-Source Analytical Platform for Analysis of C. elegans Swimming Induced Paralysis

    PubMed Central

    Hardaway, J. Andrew; Wang, Jing; Fleming, Paul A.; Fleming, Katherine A.; Whitaker, Sarah M.; Nackenoff, Alex; Snarrenberg, Chelsea L.; Hardie, Shannon L.; Zhang, Bing; Blakely, Randy D.

    2014-01-01

    Background The nematode Caenhorhabditis elegans offers great power for the identification and characterization of genes that regulate behavior. In support of this effort, analytical methods are required that provide dimensional analyses of subcomponents of behavior. Previously, we demonstrated that loss of the presynaptic dopamine (DA) transporter, dat-1, evokes DA-dependent Swimming Induced Paralysis (Swip) (Mcdonald et al. 2007), a behavior compatible with forward genetic screens (Hardaway et al. 2012). New Method Here, we detail the development and implementation of SwimR, a set of tools that provide for an automated, kinetic analysis of C. elegans Swip. SwimR relies on open source programs that can be freely implemented and modified. Results We show that SwimR can display time-dependent alterations of swimming behavior induced by drug-treatment, illustrating this capacity with the dat-1 blocker and tricyclic antidepressant imipramine (IMI). We demonstrate the capacity of SwimR to extract multiple kinetic parameters that are impractical to obtain in manual assays. Comparison with Existing Methods Standard measurements of C. elegans swimming utilizes manual assessments of the number of animals exhibiting swimming versus paralysis. Our approach deconstructs the time course and rates of movement in an automated fashion, offering a significant increase in the information that can be obtained from swimming behavior. Conclusions The SwimR platform is a powerful tool for the deconstruction of worm thrashing behavior in the context of both genetic and pharmacological manipulations that can be used to segregate pathways that underlie nematode swimming mechanics. PMID:24792527

  4. Stiffness changes of the cupula associated with the mechanics of hair cells in the fish lateral line.

    PubMed

    van Netten, S M; Khanna, S M

    1994-02-15

    Cupular vibration in the lateral-line canal of fish was measured in response to motion of the fluid in the canal by laser-heterodyne interferometry. The results show that the mechanical output/input ratio of the cupula depends on the stimulus amplitude; the cupula thus behaves nonlinearly. The nonlinearity is due to the hair bundles, since it disappears when the cupula is uncoupled from the underlying hair cells. A model of cupular dynamics in which the behavior of the gating springs of the hair cells is incorporated predicts nonlinear responses that are similar to the measurements, suggesting that the nonlinear behavior of the cupula may be attributed to the opening and closing of the transduction channels of the hair cells.

  5. 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

  6. 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

  7. 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…

  8. Sodium bicarbonate improves swimming performance.

    PubMed

    Lindh, A M; Peyrebrune, M C; Ingham, S A; Bailey, D M; Folland, J P

    2008-06-01

    Sodium bicarbonate ingestion has been shown to improve performance in single-bout, high intensity events, probably due to an increase in buffering capacity, but its influence on single-bout swimming performance has not been investigated. The effects of sodium bicarbonate supplementation on 200 m freestyle swimming performance were investigated in elite male competitors. Following a randomised, double blind counterbalanced design, 9 swimmers completed maximal effort swims on 3 separate occasions: a control trial (C); after ingestion of sodium bicarbonate (SB: NaHCO3 300 mg . kg (-1) body mass); and after ingestion of a placebo (P: CaCO3 200 mg . kg (-1) body mass). The SB and P agents were packed in gelatine capsules and ingested 90 - 60 min prior to each 200 m swim. Mean 200 m performance times were significantly faster for SB than C or P (1 : 52.2 +/- 4.7; 1 : 53.7 +/- 3.8; 1 : 54.0 +/- 3.6 min : ss; p < 0.05). Base excess, pH and blood bicarbonate were all elevated pre-exercise in the SB compared to C and P trials (p < 0.05). Post-200 m blood lactate concentrations were significantly higher following the SB trial compared with P and C (p < 0.05). It was concluded that SB supplementation can improve 200 m freestyle performance time in elite male competitors, most likely by increasing buffering capacity.

  9. Drag reduction in fish-like locomotion

    NASA Astrophysics Data System (ADS)

    Barrett, D. S.; Triantafyllou, M. S.; Yue, D. K. P.; Grosenbaugh, M. A.; Wolfgang, M. J.

    1999-08-01

    We present experimental force and power measurements demonstrating that the power required to propel an actively swimming, streamlined, fish-like body is significantly smaller than the power needed to tow the body straight and rigid at the same speed U. The data have been obtained through accurate force and motion measurements on a laboratory fish-like robotic mechanism, 1.2 m long, covered with a flexible skin and equipped with a tail fin, at Reynolds numbers up to 106, with turbulence stimulation. The lateral motion of the body is in the form of a travelling wave with wavelength [lambda] and varying amplitude along the length, smoothly increasing from the front to the tail end. A parametric investigation shows sensitivity of drag reduction to the non-dimensional frequency (Strouhal number), amplitude of body oscillation and wavelength [lambda], and angle of attack and phase angle of the tail fin. A necessary condition for drag reduction is that the phase speed of the body wave be greater than the forward speed U. Power estimates using an inviscid numerical scheme compare favourably with the experimental data. The method employs a boundary-integral method for arbitrary flexible body geometry and motions, while the wake shed from the fish-like form is modelled by an evolving desingularized dipole sheet.

  10. Persistent effects on adult swim performance and energetics in zebrafish developmentally exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin.

    PubMed

    Marit, Jordan S; Weber, Lynn P

    2012-01-15

    TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) remains a potent and persistent toxicant in aquatic environments, causing lethal developmental deformities in fish. However, few studies have examined sublethal or persistent effects of developmental TCDD exposure and none have examined its effects on swimming capabilities in sub-adult fish. The objective of the current study was to examine whether effects of TCDD exposure during the critical period of cardiovascular development (2-4 days post fertilization) on swim performance, triglyceride stores and cardiovascular deformities would persist until adulthood in zebrafish. Zebrafish larvae were exposed between 48 and 96 h post fertilization to 1, 0.1, 0.01 ng/L TCDD or DMSO control (0.005%), then raised in clean water for 90 days. Despite having equal survivability, no significant increase in gross deformities and no change in cytochrome P450 1A (CYP1A) activity was observed, while critical swimming speed and dorsal aorta diameter were significantly decreased in TCDD-exposed fish at 90 days. Furthermore, whole body triglycerides were significantly elevated in TCDD-exposed fish both before and after swim testing. Therefore sublethal TCDD exposure during zebrafish development caused a persistent decrease in swim endurance. The cause of this persistent decrease in swim endurance is not known, but may be related to behavioral adaptations limiting swimming capabilities, failure to mobilize triglyceride stores, vascular deformities limiting blood flow to the periphery, or a combination of these factors.

  11. Adiabatic Swimming in an Ideal Quantum Gas

    NASA Astrophysics Data System (ADS)

    Avron, J. E.; Gutkin, B.; Oaknin, D. H.

    2006-04-01

    Interference effects are important for swimming of mesoscopic systems that are small relative to the coherence length of the surrounding quantum medium. Swimming is geometric for slow swimmers and the distance covered in each stroke is determined, explicitly, in terms of the on-shell scattering matrix. Remarkably, for a one-dimensional Fermi gas at zero temperature we find that slow swimming is topological: the swimming distance covered in one stroke is quantized in half integer multiples of the Fermi wavelength. In addition, a careful choice of the swimming stroke can eliminate dissipation.

  12. Micro- and nanorobots swimming in heterogeneous liquids.

    PubMed

    Nelson, Bradley J; Peyer, Kathrin E

    2014-09-23

    Essentially all experimental investigations of swimming micro- and nanorobots have focused on swimming in homogeneous Newtonian liquids. In this issue of ACS Nano, Schamel et al. investigate the actuation of "nanopropellers" in a viscoelastic biological gel that illustrates the importance of the size of the nanostructure relative to the gel mesh size. In this Perspective, we shed further light on the swimming performance of larger microrobots swimming in heterogeneous liquids. One of the interesting results of our work is that earlier findings on the swimming performance of motile bacteria in heterogeneous liquids agree, in principle, with our results. We also discuss future research directions that should be pursued in this fascinating interdisciplinary field.

  13. 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

  14. 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.

  15. 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

  16. Amoeboid swimming in a channel.

    PubMed

    Wu, Hao; Farutin, Alexander; Hu, Wei-Fan; Thiébaud, Marine; Rafaï, Salima; Peyla, Philippe; Lai, Ming-Chih; Misbah, Chaouqi

    2016-09-28

    Several micro-organisms, such as bacteria, algae, or spermatozoa, use flagellar or ciliary activity to swim in a fluid, while many other micro-organisms instead use ample shape deformation, described as amoeboid, to propel themselves either by crawling on a substrate or swimming. Many eukaryotic cells were believed to require an underlying substratum to migrate (crawl) by using membrane deformation (like blebbing or generation of lamellipodia) but there is now increasing evidence that a large variety of cells (including those of the immune system) can migrate without the assistance of focal adhesion, allowing them to swim as efficiently as they can crawl. This paper details the analysis of amoeboid swimming in a confined fluid by modeling the swimmer as an inextensible membrane deploying local active forces (with zero total force and torque). The swimmer displays a rich behavior: it may settle into a straight trajectory in the channel or navigate from one wall to the other depending on its confinement. The nature of the swimmer is also found to be affected by confinement: the swimmer can behave, on average over one swimming cycle, as a pusher at low confinement, and becomes a puller at higher confinement, or vice versa. The swimmer's nature is thus not an intrinsic property. The scaling of the swimmer velocity V with the force amplitude A is analyzed in detail showing that at small enough A, V∼A(2)/η(2) (where η is the viscosity of the ambient fluid), whereas at large enough A, V is independent of the force and is determined solely by the stroke cycle frequency and the swimmer size. This finding starkly contrasts with models where motion is based on ciliary and flagellar activity, where V∼A/η. To conclude, two definitions of efficiency as put forward in the literature are analyzed with distinct outcomes. We find that one type of efficiency has an optimum as a function of confinement while the other does not. Future perspectives are outlined. PMID:27546154

  17. 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

  18. 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.

  19. 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

  20. 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.

  1. Response acquisition by Siamese fighting fish (Betta splendens) with delayed visual reinforcement

    PubMed Central

    Lattal, Kennon A.; Metzger, Barbara

    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

  2. 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

  3. 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.

  4. 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.

  5. Oxidative stress as a mechanism for PAH phototoxicity in cultured fish cells

    SciTech Connect

    Reber, J.M.; Spacie, A.; Collodi, P.

    1994-12-31

    Although certain PAH are known to be phototoxic, the mechanism for this process has not been previously demonstrated. In this paper, the authors present evidence for oxidative stress as a mechanism for such phototoxicity. The effects of three PAH (anthracene, pyrene, and fluoranthene) on cultured zebrafish (Brachydanio rerio) embryo cells were examined. Oxyradical promoters (diethyldithiocarbamic acid (DDC), 1-chloro-2,4-dinitrobenzene (CDNB), maleic acid diethyl ester (MADE) and DL-buthionine-[S,R]-sulfoximine (BSO)) were added at sublethal levels as pretreatments or cotreatments with the three PAH phototoxicants. Oxyradical inhibitors (1,10-phenanthroline and Quin 2 AM) were added at sublethal levels as cotreatments with the phototoxicants. The PAH were found to be significantly more toxic in the presence of UV light than plain white fluorescent light. All three of these PAH were found to be significantly more toxic if combined with any of the oxyradical promoters, but only in the presence of UV. Further, these phototoxicants were found to be significantly less toxic in combination with the oxyradical inhibitors, even in the presence of UV. From these results the authors conclude that oxidative stress is an important mechanism of phototoxicity.

  6. How body torque and Strouhal number change with swimming speed and developmental stage in larval zebrafish

    PubMed Central

    van Leeuwen, Johan L.; Voesenek, Cees J.; Müller, Ulrike K.

    2015-01-01

    Small undulatory swimmers such as larval zebrafish experience both inertial and viscous forces, the relative importance of which is indicated by the Reynolds number (Re). Re is proportional to swimming speed (vswim) and body length; faster swimming reduces the relative effect of viscous forces. Compared with adults, larval fish experience relatively high (mainly viscous) drag during cyclic swimming. To enhance thrust to an equally high level, they must employ a high product of tail-beat frequency and (peak-to-peak) amplitude fAtail, resulting in a relatively high fAtail/vswim ratio (Strouhal number, St), and implying relatively high lateral momentum shedding and low propulsive efficiency. Using kinematic and inverse-dynamics analyses, we studied cyclic swimming of larval zebrafish aged 2–5 days post-fertilization (dpf). Larvae at 4–5 dpf reach higher f (95 Hz) and Atail (2.4 mm) than at 2 dpf (80 Hz, 1.8 mm), increasing swimming speed and Re, indicating increasing muscle powers. As Re increases (60 → 1400), St (2.5 → 0.72) decreases nonlinearly towards values of large swimmers (0.2–0.6), indicating increased propulsive efficiency with vswim and age. Swimming at high St is associated with high-amplitude body torques and rotations. Low propulsive efficiencies and large yawing amplitudes are unavoidable physical constraints for small undulatory swimmers. PMID:26269230

  7. 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.

  8. Decreased body temperature dependent appearance of behavioral despair in the forced swimming test in mice.

    PubMed

    Arai, I; Tsuyuki, Y; Shiomoto, H; Satoh, M; Otomo, S

    2000-08-01

    Effects of body temperature on the immobile response and brain glucose metabolism were examined in the forced swimming test in mice. The first experiment was performed to study behavior, after initial periods of vigorous activity, a characteristic immobile posture occurred when the water was 25 and 35 degrees C. However, several minutes after forced swimming at 25 degrees C, significantly decreased spontaneous motility occurred in a time-dependent manner, but no changes was observed at 35 degrees C. Our interpretation was that mechanisms of acquisition and retention of the forced swim-induced immobile response differed. Body temperature was also significantly decreased at 25 degrees C but not at 35 degrees C in the forced swimming test. This lowering of body temperature almost paralleled the immobile response. The second experiment was a biochemical study in which the uptake of [(14)C] 2-deoxy-d-glucose into the brain significantly decreased after forced swimming at 25 degrees C but did not change in the forced swim loaded mice when the water was 35 degrees C. These results suggested two types of immobile mechanisms in the forced swimming test: (1) an early phase acquisition of the immobile response which might be related to adaptive response and (2) a late phase to retain the immobile response which might be related to the decrease in brain glucose metabolism.

  9. 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

  10. 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.

  11. Ultraviolet polarization vision in fishes: possible mechanisms for coding e-vector.

    PubMed Central

    Hawryshyn, C W

    2000-01-01

    Polarization vision in vertebrates has been marked with significant controversy over recent decades. In the last decade, however, models from two laboratories have indicated that the spatial arrangement of photoreceptors provides the basis for polarization sensitivity Work in my laboratory, in collaboration with I. Novales Flamarique and F. I. Harosi, has shown that polarization sensitivity depends on a well-defined square cone mosaic pattern and that the biophysical properties of the square cone mosaic probably account for polarization vision in the ultraviolet spectrum. The biophysical mechanism appears to be based on the selective reflection of axial-polarized light by the partitioning membrane, formed along the contact zone between the members of the double cones, onto neighbouring ultraviolet-sensitive cones. In this short review, I discuss the historical development of this research problem. PMID:11079395

  12. Extreme lifespan of the human fish (Proteus anguinus): a challenge for ageing mechanisms

    PubMed Central

    Voituron, Yann; de Fraipont, Michelle; Issartel, Julien; Guillaume, Olivier; Clobert, Jean

    2011-01-01

    Theories of extreme lifespan evolution in vertebrates commonly implicate large size and predator-free environments together with physiological characteristics like low metabolism and high protection against oxidative damages. Here, we show that the ‘human fish’ (olm, Proteus anguinus), a small cave salamander (weighing 15–20 g), has evolved an extreme life-history strategy with a predicted maximum lifespan of over 100 years, an adult average lifespan of 68.5 years, an age at sexual maturity of 15.6 years and lays, on average, 35 eggs every 12.5 years. Surprisingly, neither its basal metabolism nor antioxidant activities explain why this animal sits as an outlier in the amphibian size/longevity relationship. This species thus raises questions regarding ageing processes and constitutes a promising model for discovering mechanisms preventing senescence in vertebrates. PMID:20659920

  13. Behavior, metabolism and swimming physiology in juvenile Spinibarbus sinensis exposed to PFOS under different temperatures.

    PubMed

    Xia, Ji-Gang; Nie, Li-Juan; Mi, Xia-Mei; Wang, Wei-Zhen; Ma, Yi-Jie; Cao, Zhen-Dong; Fu, Shi-Jian

    2015-10-01

    The harmful effects of perfluorooctane sulfonate (PFOS) are of growing international concern. This paper aimed to gain an integrated understanding of fitness-related ecological end points, such as behavior, metabolism and swimming physiology, in juvenile Spinibarbus sinensis in response to PFOS toxicity at different temperatures. The fish were exposed to a range of PFOS concentrations (0, 0.32, 0.8, 2 and 5 mg/L) at different temperatures (18 and 28 °C) for 30 days. The effects on fish behavior, metabolic characteristics and aerobic swimming performance caused by PFOS at different temperatures were investigated. Our results showed that both PFOS and temperature had important influences on spontaneous swimming behavior, social interactions, routine metabolic rate (RMR), net energetic cost of transport (COTnet) and critical swimming speed (U crit) in fish. The lowest observed effect concentration for both U crit and RMR was 5 and 0.8 mg/L at 18 and 28 °C, respectively. We found that PFOS affected various behavioral and social end points and also appeared to affect metabolic rates and reduced U crit, likely as a result of increased COTnet, and that many of these effects also changed with respect to temperature. Our results further the understanding of the metabolic and behavioral toxicity of PFOS to aquatic organisms.

  14. Team swimming in ant spermatozoa.

    PubMed

    Pearcy, Morgan; Delescaille, Noémie; Lybaert, Pascale; Aron, Serge

    2014-06-01

    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

  15. Optimal swimming of model ciliates

    NASA Astrophysics Data System (ADS)

    Michelin, Sebastien; Lauga, Eric

    2010-11-01

    In order to swim at low Reynolds numbers, microorganisms must undergo non-time-reversible shape changes. In ciliary locomotion, this symmetry breaking is achieved through the actuation of many flexible cilia distributed on the surface of the organism. Experimental studies have demonstrated the collective synchronization of neighboring cilia (metachronal waves), whose exact origin is still debated. Here we consider the hydrodynamic energetic cost of ciliary locomotion and consider an axisymmetric envelope model with prescribed tangential surface displacements. We show that the periodic strokes of this model ciliated swimmer that minimize the energy dissipation in the surrounding fluid achieve symmetry-breaking at the organism level through the propagation of wave patterns similar to metachronal waves. We analyze the properties of the optimal strokes, in particular the impact on the swimming performance introduced by a restriction on maximum cilia tip displacement due to the finite cilia length.

  16. Team swimming in ant spermatozoa.

    PubMed

    Pearcy, Morgan; Delescaille, Noémie; Lybaert, Pascale; Aron, Serge

    2014-06-01

    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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  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.

  3. Effects of chronic dietary selenomethionine exposure on repeat swimming performance, aerobic metabolism and methionine catabolism in adult zebrafish (Danio rerio).

    PubMed

    Thomas, Jith K; Wiseman, Steve; Giesy, John P; Janz, David M

    2013-04-15

    In a previous study we reported impaired swimming performance and greater stored energy in adult zebrafish (Danio rerio) after chronic dietary exposure to selenomethionine (SeMet). The goal of the present study was to further investigate effects of chronic exposure to dietary SeMet on repeat swimming performance, oxygen consumption (MO2), metabolic capacities (standard metabolic rate [SMR], active metabolic rate [AMR], factorial aerobic scope [F-AS] and cost of transport [COT]) and gene expression of energy metabolism and methionine catabolism enzymes in adult zebrafish. Fish were fed SeMet at measured concentrations of 1.3, 3.4, 9.8 or 27.5 μg Se/g dry mass (d.m.) for 90 d. At the end of the exposure period, fish from each treatment group were divided into three subgroups: (a) no swim, (b) swim, and (c) repeat swim. Fish from the no swim group were euthanized immediately at 90 d and whole body triglycerides, glycogen and lactate, and gene expression of energy metabolism and methionine catabolism enzymes were determined. Individual fish from the swim group were placed in a swim tunnel respirometer and swimming performance was assessed by determining the critical swimming speed (U(crit)). After both Ucrit and MO2 analyses, fish were euthanized and whole body energy stores and lactate were determined. Similarly, individual fish from the repeat swim group were subjected to two U(crit) tests (U(crit-1) and U(crit-2)) performed with a 60 min recovery period between tests, followed by determination of energy stores and lactate. Impaired swim performance was observed in fish fed SeMet at concentrations greater than 3 μg Se/g in the diet. However, within each dietary Se treatment group, no significant differences between single and repeat U(crits) were observed. Oxygen consumption, SMR and COT were significantly greater, and F-AS was significantly lesser, in fish fed SeMet.