A complex method of race determination based on the genetic, parasitological and morphological traits of the population was proposed to obtain a reliable scheme of distribution and migrations of the Azov and Black Sea anchovy stocks. The abundance of anchovy was determined using the data from surveys performed with standard trawl and hydroacoustic equipment. Experiments revealed considerable changes in the Azov anchovy’s gene pool. The main reason was the increasing of water salinity as a result of river in-flow regulation. The excessive industrial catching also promoted the process. As a result, the proportion of hybrids increased. According to the data of the acoustic surveys in the waters of the former USSR in the period from 1980 to 1988, the average biomass of the Black Sea anchovy aggregations was 309,000 tons, and the biomass of the Azov anchovy, 169,000 tons. Since 1988 the situation of these stocks have dramatically changed. A great decrease of the populations has occurred. That has in all evidence been caused by excessive captures of anchovy by the USSR and Turkey. An additional important negative factor were the intrusions of a jellyfish, Mnemiopsis leidyi. The biomass of the anchovy near the Georgian coast increased up to 165,000 tons after the Mnemiopsis outbreak had passed its peak in winter 1991-92.