Sexual Dimorphism of Physiological and Biochemical State of Trunk Muscle in Bleak (Alburnus alburnus L.) (Cypriniformes, Cyprinidae) Spawners of the Rybinsk Reservoir in the Prespawning Period

Abstract

The sexual dimorphism of physiological and biochemical parameters of trunk muscle in bleak spawners, representatives of an abundant nonexploited fish species of the Rybinsk Reservoir, has been analyzed in the prespawning period. Sex-related differences in the overall biochemical and lipid composition of trunk muscle and in muscle composition variability in age- and size-matched individuals have been assessed. The distribution of trunk-muscle lipid content is bimodal in females and unimodal in males. The variability of muscle lipid parameters in the aggregated samples is higher in females than in males. The putative reasons for the distinctive features of physiological and biochemical parameters of muscle tissue detected in bleak of different sexes in the prespawning period are discussed.