Effects of Temperature on the Maximum Swimming Speed of Fishes

Abstract

Teleost fish inhabit a great variety of ecological niches throughout the world where temperature may range from below the freezing point of water to as high as 40°C. There are probably few or none of the 20,000 species that can survive even a slow change through this full range of temperature, but some species have evolved with quite wide temperature tolerance in order to survive in particular temperate or extreme climate habitats. The temperature of the body tissues of most teleost species is generally considered to equilibrate rapidly with any change in water temperature. Changes in the temperature of the tissues cause complicated changes in the rates of metabolic processes and enzymes and other components of the tissue biochemistry can become more or less active. Maximum swimming speed is severely reduced in cold water probably as a result of the effects of low temperature on the biochemical and physiological processes involved in muscle contraction. Whatever the cause the observation is that the twitch contraction of the anaerobic fast white swimming muscle of the fish becomes longer as the muscle is cooled. This paper defines the effect of changing the temperature of the swimming muscle on the muscle contraction time and examines the consequent effect on the maximum swimming speed. Some adaptation and compensation tactics that might help regain the speed lost in cold water are also examined.