EVALUATION OF THE POSSIBILITY OF SEX IDENTIFICATION IN A STERLET BY MORPHOMETRIC INDICATORS OF THE STRUCTURE OF THE TAIL STEM

Abstract

Representatives of the sturgeon family do not have pronounced external sex differences, which are typical of most aquaculture fishes. This causes some difficulties in their cultivation, the effectiveness of which largely depends on the timely division of the herd of fish into males and females, especially in caviar-commercial sturgeon farming. To date, none of the available methods for determining the sex of sturgeon is perfect. Some are traumatic, others are too expensive to use in commercial fisheries. This encourages the search for new methods and the development of effective ways to separate sturgeon by sex, which determines the relevance of research in this area. The aim of the study was to test the hypothesis of the presence of sex differences in the linear size of the tail stem in a member of the sturgeon family - sterlet (Acipenser ruthenus Linnaeus). The object of the study is the morphometric parameters of the tail stalk in the sterlet of adulthood. The subject of the study - differences in the structure of the tail of males and females of sterlet. Research methods - generally accepted in fisheries science ichthyological and statistical. The study was conducted in the training, research and production laboratory of fish farming of the Department of Aquaculture NULES of Ukraine in April and December 2019. The material for the study were the offspring of sterlet from a flock of fish kept in a closed recirculation aquaculture system of the fish farming laboratory. According to the results of the study, the hypothesis of a difference in the size of the tail stalk in male and female sterlet was not confirmed. However, according to the materials of pairwise correlation analysis of the dependence of the values of the indices of the structure of the tail stem on the age of the fish, a moderate inverse relationship was found between the relative thickness of the tail stem and the age of males and females of this fish. Females also showed an increase in the relative length of the tail stem with age. It was determined appropriate to continue similar studies on immature sterlet, aged 2 to 5 years.