We describe and characterize a method for estimating the pressure field corresponding to velocity field measurements such as those obtained by using particle image velocimetry. The pressure gradient is estimated from a time series of velocity fields for unsteady calculations or from a single velocity field for quasi-steady calculations. The corresponding pressure field is determined based on me...

Undulatory locomotion is an archetypal mode of propulsion for natural swimmers across scales. Undulatory swimmers convert transverse body oscillations into forward velocity by a complex interplay between their flexural movements, morphological features and the fluid environment. Natural evolution has produced a wide range of morphokinematic examples of undulatory swimmers that often serve as in...

For nearly a century, researchers have tried to understand the swimming of aquatic animals in terms of a balance between the forward thrust from swimming movements and drag on the body. Prior approaches have failed to provide a separation of these two forces for undulatory swimmers such as lamprey and eels, where most parts of the body are simultaneously generating drag and thrust. We nonethele...

Of more than 800 species of eels of the order Anguilliformes, only freshwater eels (genus Anguilla with 16 species plus three subspecies) spend most of their lives in freshwater during their catadromous life cycle. Nevertheless, because their spawning areas are located offshore in the open ocean, they migrate back to their specific breeding places in the ocean, often located thousands of kilome...

Animals move through their environments using muscles to produce force. When an animal׳s nervous system activates a muscle, the muscle produces different amounts of force depending on its length, its shortening velocity, and its time history of force production. These muscle forces interact with forces from passive tissue properties and forces from the external environment. Using an integrative...

Acipensericola petersoni n. gen., n. sp. (Digenea: Aporocotylidae) infects the heart of the American paddlefish Polyodon spathula (Walbaum, 1792) in the Mississippi Delta. It has robust, spike-like body spines arranged in ventrolateral transverse rows; a bowl-shaped anterior sucker centered on the mouth and having minute spines on the inner anteroventral surface only; a pharynx; an inverse U-sh...

# 2002 Blackwell Science Ltd 63 Abstract Axial swimming in ¢sh varies across a range of body forms and swimming modes. Swimmingbyeels, tunas,mackerels, scup, rainbow trout and bass span this range from high curvature anguilliform swimmers to rigid body thunniform swimmers. Recent work on these and other species has elucidated an impressive array of solutions to the problem of how to use the red...