Biological data on the Danube ruffe, Gymnocephalus baloni Holčík et Hensel, 1974, in the Desna River, Ukraine

Abstract

The Danube ruffe, Gymnocephalus baloni Holčík et Hensel, 1974, is a little-known species from the middle and lower Danube River. The relevant information on its habitat, maturity, fecundity, spawning season, maximum size and age, as well as its growth and length-weight relation are provided herewith from the Desna River, Ukraine. The estimation of fecundity ranged from 5072 to 15 730 eggs within the length range of 8.6 to 10.4 cm SL and the gonado-somatic index was 0.12-0.14 respectively. The length-weight relation was determined as W = 0.0345SL2.83.