Comparative Morphological Characteristics of Sterlet from Various Aquacultural Populations
The aim of the research was to study the exterior indicators and inner organs of the sterlet, grown in various aquacultural populations. The mass of the body, inner organs (liver, kidney, heart and fish mow, stomach, intestinal tract, gonads) and such morphometric indicators as absolute length of the body, the length of the tail stem, the largest hight of the body, the largest circumference, the thickness of the body, the least hight of the body, the length, hight and width of the head, the space behind the eyes (the distance from the rear part of the eye to the most remote from fi nal poit of the operculum), the diameter of the eye, the length of the snout, distance 1 - from the end of the snout to the lip, distance 2 - from the end of the snout to the beginning of the gravel roof of the mouth, distance 3 - from the end of the snout to the line crossing the middle of the base of the pair of the feelers, distance 4 - from the line crossing the middle of the base of the middle pair of feelers to the beginning of gravel roof of the mouth (cm) were defi ned. The sterlet studied is of the similar age: Yaroslavl 2,60±0,16 and Tver 2,33±0,33 years. In fact the largest values of the body mass and morphometrical indicators are also observed in Yaroslavl sterlet, and the largest gonads - in Tver ones. The average coefficient of the state of nourishment of sterlets from various aquacultural populations was close (0,57 and 0,60). Yaroslavl slerlet has a high scattering of the given indicator as well as lipid deposits in the internal organs of fish with a high coefficient of the state of nourishment. The analysis of interrelation of morphological signs stated that the highest positive interrelation was found for the greatest circumference with the largest hight of the body. Highly interrelated examples may refer to the largest hight with the length of the head and the hight of the proctoral fin, the greatest circumference with the length and width of the head and the height of the proctoral fin.