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  • Author: S. V. Kokodiy x
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S. V. Kokodiy

Abstract

The following proofs of Goldfish more powerful reproductive potential are given: high individual and relative fecundity, adequate fractional spawning process resulting in numerous off spring, represented by different generations of hatchlings, little number of individuals not participating in reproduction, prevailing number of fish eggs in females’ ovaries, larger fraction of impregnated roe. All the above mentioned factors allow claiming that the Prussian carp is being replaced due to its low replacement ability. Perhaps for that reason Carassius gibelio (Bloch, 1782) choose small isolated water bodies, where it makes small populations, backed up by successful spawning with a single male of crucian carp, Carassius carassius (Linnaeus, 1758).

Open access

S. V. Kokodiy

Abstract

The genetic structure of crucian carps colonies in Ukrainian water bodies was defined by gene marking. The sexual structure and ploidy were investigated, the duration of spawners maturation, life-span, rate of growth and the linear growth of independent species and biotypes were defined. The comparative biological analysis showed that virtually all the researched crucian carps had low linear growth index and early maturation terms. Th e hybrid individuals of C. auratus-C. carassius during the first years of life were characterized by the high rate of growth which was most likely determined by the “hybrid power” which is kept by this biotype only within the starting phase of existence, after which the active growth is significantly reduced. Th e individual biological peculiarities of peculiar species and biotypes of crucian carps do not depend on their genetic nature but in most cases are defined by the external living conditions.

Open access

A. O. Tsyba and S. V. Kokodiy

Abstract

In the upper reaches of the Dnipro it was found a Danube ruffe population. It differs from the population of the middle reaches of the Dnipro by a longer caudal peduncle. The Danube ruffe differs from sympatric populations of the common ruffe by 10 features. For a fast and precise identification of these two species, it was proposed to use the height of the membrane between the first and second rays of the anal fin as a percentageto the length of the body.

Open access

S. V. Mezhzherin, S. V. Kokodiy, P. P. Pukhtaevitch and A. V. Kulish

Abstract

Study of population structure of crucian carps in the mixed forests zone of Northern Ukraine (characterized by ample diversity of unregulated aquatic systems) showed the presence of diploid C. carassius and C. auratus, triploid C. gibelio (represented by a series of clones), C. auratus × C. carassius diploid hybrids, and tetraploid hybrids between C. carassius and C. gibelio. The crucian carps of the region compared with those of more southern zones of Ukraine are characterized by numerical prevalence of unisexual form of C. gibelio, and relatively restricted hybridization of C. carassius and C. auratus.