Some biological data on cactus roach, Rutilus virgo (Heckel), in rivers of the Transcarpathian region of Ukraine

Abstract The occurrence of Rutilus virgo (Heckel) has been confirmed in the Transcarpathian region of Ukraine, where it was caught in the lower stretches of the Latorica and Borzhava rivers. The comparison of selected morphometric features of R. rutilus and R. virgo showed that 26 of 40 of them were significantly different and the largest differences were observed for features such as head length, maximum body depth, pectoral fin length, pectoral fin thickness, pelvic fin length, head depth at eye level, maximum head depth, and preorbital length. The comparison of R. virgo of two size groups showed a number of changes in fish body proportions during fish growth, where 29 of 38 features were different. Length-weight relationship for mixed sexes was a = 0.0157, b = 3.088. The fecundity of R. virgo depended on age and varied from 6775 eggs (age 4+) to 51535 eggs (age 8+). R. virgo inhabiting the rivers of the Transcarpathian region is characterized by relatively rapid growth rate, and the results are within growth rate limits reported in the literature.