RELATION BETWEEN VISTULA SEA TROUT (Salmo trutta L.) EGG SIZE AND SIZE OF FEMALES

Abstract

Body length and mass of 2031 Vistula sea trout females, the two diameters of their eggs, and volume of 30 eggs were measured in 1969-1994. The results indicate that one diameter only is sufficient for determining egg size of the species, and that measurement of egg volume may be used instead of egg diameter. Size variability of the Vistula sea trout eggs obtained from one female is small, and egg size depends on the size of the female. The study revealed also that eggs were slightly ellipsoidal, their shape was little variable, and did not depend on the size of females. Vistula sea trout populations in particular years of the study did not vary with respect to egg size.