George V. Lauder

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A key evolutionary transformation of the locomotor system of ray-finned fishes is the morphological elaboration of the dorsal fin. Within Teleostei, the dorsal fin primitively is a single midline structure supported by soft, flexible fin rays. In its derived condition, the fin is made up of two anatomically distinct portions: an anterior section supported(More)
Eels undulate a larger portion of their bodies while swimming than many other fishes, but the hydrodynamic consequences of this swimming mode are poorly understood. In this study, we examine in detail the hydrodynamics of American eels (Anguilla rostrata) swimming steadily at 1.4 L s(-1) and compare them with previous results from other fishes. We performed(More)
Past study of interspecific variation in the swimming speed of fishes has focused on internal physiological mechanisms that may limit the ability of locomotor muscle to generate power. In this paper, we approach the question of why some fishes are able to swim faster than others from a hydrodynamic perspective, using the technique of digital particle image(More)
As members of the derived teleost fish clade Scombridae, mackerel exhibit high-performance aquatic locomotion via oscillation of the homocercal forked caudal fin. We present the first quantitative flow visualization of the wake of a scombrid fish, chub mackerel Scomber japonicus (20-26 cm fork length, FL), swimming steadily in a recirculating flow tank at(More)
We analyzed midline kinematics and obtained electromyograms (EMGs) from the superficial red muscle at seven longitudinal positions in four largemouth bass swimming steadily at standardized speeds of 0.7, 1.2, 1.6, 2.0 and 2.4 lengths s21. Analysis of variance was used to test for significant variation attributable to both speed and longitudinal position.(More)
Fishes moving through turbulent flows or in formation are regularly exposed to vortices. Although animals living in fluid environments commonly capture energy from vortices, experimental data on the hydrodynamics and neural control of interactions between fish and vortices are lacking. We used quantitative flow visualization and electromyography to show(More)
Most fishes commonly experience unsteady flows and hydrodynamic perturbations during their lifetime. In this study, we provide evidence that rainbow trout Oncorhynchus mykiss voluntarily alter their body kinematics when interacting with vortices present in the environment that are not self-generated. To demonstrate this, we measured axial swimming(More)
Dorsal and anal fins are median fins located above and below the centre of mass of fishes, each having a moment arm relative to the longitudinal axis. Understanding the kinematics of dorsal and anal fins may elucidate how these fins are used in concert to maintain and change fish body position and yet little is known about the functions of these fins. Using(More)
The myomeric axial musculature of fish has a complex three-dimensional morphology, yet within-myomere motor patterns have not been examined to determine whether all portions of each myomere are activated synchronously during locomotion. To gain insight into recruitment patterns in the deep myomeric musculature of fish, we implanted a series of fine-wire(More)
We quantified the intensity and duration of electromyograms (emgs) from the red and white axial muscles in five bluegill sunfish (Lepomis macrochirus) which performed three categories of behavior including steady swimming and burst and glide swimming at moderate and rapid speeds. Steady swimming (at 2 lengths/s) involved exclusively red muscle activity(More)