Reproductive capacities in the polyploid males of spined loaches from the unisexual-bisexual complex, occurred in the Moscow River.

The unisexusal-bisexual complex of spined loaches from genus Cobitis, occurred in the Moscow River, includes two tetraploid forms. One of them consists of males and females. The studies of spermatogenesis as well as spermatozoa mobility and ultrastructure, of these males were performed simultaneously with experimental crosses to define their reproductive capacities.