The karyotypes of one mud loach and three spined loach species occurring in the Far East region of Russia are presented. Misgurnus nikolskyi has 2n=50 with NF=64, Cobitis lutheri has 2n=50 and NF=70, C. choii has 2n=50 and NF=68, and C. melanoleuca has 2n=50 and NF=72. The karyotype of M. mohoity is proved to consist of 50 chromosomes. These results are discussed in relation with some taxonomic and evolution problems in loaches
The comparative craniological analysis of the short-barb Crimean gudgeon from the Chernaya River (south-western Crimea) and G. gobio from the Volga River basin, as well as the study of morphological cahracters used for identification of G. gobio carpathicus natio krymensis by B e r g (1949) and G. gobio kovatschevi by B ă n ă r e s c u et al. (1999) resulted in conclusion about the specific status of G. krymensis. Several craniological characters, namely the relative lengths of supracleithra and cleithra, preopercle width and the modal numbers of pores in several bones, are presumed to be available characters for its identification, as well as barbel length.
This review compares the current state of ichthyofauna in the largest rivers of the northern coast of the Black Sea (Don, Kuban, Dnieper and Dniester rivers) with data published by B e r g (1948–1949). Changes in species composition are characterized by the disappearance or decline in anadromous and semi-anadromous fishes. The total number of native species that are extinct, protected, in declined or become rare has reached from 19 % in the Kuban to 36 % in the Dnieper River basins. Appreciable changes have occurred in the ratios between rheophilous and limnophilous fishes (the latter becoming predominant in many parts of the rivers). Euryhaline and even marine species have invaded most of river basins. And the number of introduced or established alien species varies from 9.7 % in the Dnieper to 16.8 % in the Kuban River basins. These changes, which have yielded quite altered ichthyofauna, must be taken into consideration in conservation endeavours.