Comparative characteristics of female Ladoga palia (Salvelinus Alpinus L.), grown in the conditions of fish farming in the Leningrad region by size, weight and reproductive characteristics

Abstract

Purpose: to conduct a comparative characterization of females matured for the first time at the age of 4 and 5 years according to the main mass-dimensional and reproductive characteristics.Materials and methods. Experimental studies were carried on the basis of the Federal Fish Breeding Genetic Center (FSGTSR). The object of the study was female Ladoga char (Salvelinu salpinus L.) of the III generation, which reached puberty at 4- (n=50) and 5-year-olds. (n=45) age. Females of the second generation of factory breeding were individually assessed in two stages: during the first spawning at the age of five years (2019) and in the next spawning season at the age of six years (2020). When measuring the body and collecting genital products, clove oil was used as an anesthetic. Anesthesia was performed by placing the fish in an aqueous solution of clove oil at a concentration of 0,15–0,2 ml/l for 2–3 minutes.Results. When evaluating mature females at the age of 4 and 5 years, it was found that with a statistically significant increase in body weight of five-year-olds from 1869.3 ± 57.5 to 2156.6 ± 96.53, the multiplicity between the body weight limits did not change with age and is 3 ,2. For other criteria, there is a tendency to decrease in variability. A statistically significant increase in the average weight of one egg is observed, provided that the average values of other reproductive traits do not differ. At the same time, the variability of these signs in five-year-olds is higher than in four-year-olds. So the working fertility increased from 37,4 to 55,1 %, and relative from 26,8 to 43,7 %. Correlation analysis showed the appearance of a weak negative relationship with age between relative fecundity and most of the weight-size traits, otherwise the general trends were preserved in conjunction with an increase in positive correlation.