Morphohistological studies of the gonads of hybrid polyploid loach cobitis from the Lower Dniester

In the lower Dniester, polyploid females of the hybrid complex Cobitis taenia are a portion spawning species with asynchronous development of germ cells during the entire breeding period. The spawning season in this water basin begins in the second decade of May and ends in July. In the population, in parallel with females, hermaphrodite individuals are also present, in which the ovary zone is functional, and the testis zone is sterile. A decrease in the relative mass of the gonads of subsequent generations was noted, which leads to a consistent decrease in the value of the gonadosomatic index, in females, before the second and third spawning.