Morphologic aspects of fish lateral muscles

Abstract

In fish, the lateral locomotor muscles constitute the main edible part and represent the biggest part of the body mass, when compared with those of other vertebrates. The aquatic environment and the necessity of locomotion require a characteristic arrangement of the musculature and can be compared, in the evolutionary scale, among amphioxus, lampreys, elasmobranchiomorph and teleost. Many aspects of the muscle ultrastructure are similar in every vertebrate, but the teleost fish has some peculiarity, like a characteristic interlacing of the filaments of myosin in the band-A of the sarcomere. The fish locomotor system is very specialized and can be divided in parts with different kinds of fibers: white, red and pink, essential for different velocities and times of locomotion, been extremely plastic and adaptive in many conditions of the aquatic environment. This can be utilized like a toll in cases of alterations of rearing conditions, in order to increase the efficiency of the reservoir re-stocking programs and that of production systems.