In addition to forward undulatory swimming, eels (and some other elongated swimmers) can swim backwards in a similar way. We compared the kinematics (wave speed, cycle frequency, amplitude, local bending and estimated muscle strain) of forward and backward swimming in the European eel Anguilla anguilla. Both swimming modes are characterised by a wave of undulation that travels over the body in ...

Predictions of organismal movements in a fluid require knowing the fluid's velocity and potential contributions of the organism's behaviour (e.g. swimming or flying). While theoretical aspects of this work are reasonably well-developed, field-based validation is challenging. A much-needed study recently published by Briscoe and colleagues in Proceedings of the Royal Society B compared movements...

The zebrafish Danio rerio exhibits substantial morphological variability in the sizes and shapes of the body and the caudal fin. The present study describes swimming performance, swimming behaviour and routine locomotor activity patterns in three of the major morphotypes: wild-type, long-finned and no-tail. Wild-type and long-finned differ in total length (TL), fork length (FL), caudal fin leng...

Teleost fish possess discrete blocks of oxidative red muscle (RM) and glycolytic white muscle, whereas tetrapod skeletal muscles are mixed oxidative/glycolytic. It has been suggested that the anatomy of RM in teleost fish could lead to higher intramuscular O2 partial pressures (PO2) than in mammalian skeletal muscles. This study provides the first direct experimental support for this suggestion...

The aim of this study was to investigate the effect of the head position on passive drag with a towing-line experiment in a swimming pool. The tests were performed on ten male swimmers with regional level swimming skills and at least 10 years of competitive swimming experience. They were towed underwater (at a depth of 60 cm) at three speeds (1.5, 1.7 and 1.9 m/s) and in two body positions (arm...

Although steady swimming has received considerable attention in prior studies, unsteady swimming movements represent a larger portion of many aquatic animals' locomotive repertoire and have not been examined extensively. Squids and cuttlefishes are cephalopods with unique muscular hydrostat-driven, dual-mode propulsive systems involving paired fins and a pulsed jet. These animals exhibit a wide...

In pteropod mollusks, the gastropod foot has evolved into two broad, wing-like structures that are rhythmically waved through the water for propulsion. The flexibility of the wings lends a tremendous range of motion, an advantage that could be exploited when changing locomotory speed. Here, we investigated the kinematic changes that take place during an increase in swimming speed in the pteropo...

Background Prostaglandin (PG) D2 is the most abundant prostaglandin in the mammalian brain. The physiological and pharmacological actions of PGD2 in the central nervous system seem to be associated with some of the symptoms exhibited by patients with major depressive disorder. Previous studies have found that PGD2 synthase was decreased in the cerebrospinal fluid of major depressive disorder pa...

This study reports the first results on telemetry of caudal differential pressure during spontaneous swimming activity in cod Gadus morhua and demonstrates that tail-beat pressure may be used as a predictor of activity and swimming costs of free-swimming cod. Tail-beat pressure was monitored using a differential pressure sensor on the caudal peduncle of cod and spontaneous swimming activity was...

Swimming performance tests of fish have been integral to studies of muscle energetics, swimming mechanics, gas exchange, cardiac physiology, disease, pollution, hypoxia and temperature. This paper describes a flexible protocol to assess fish swimming performance using equipment in which water velocity can be controlled. The protocol involves one to several stepped increases in flow speed that a...