Alien Fish Species of the Ukrainian Part of the Dniester River Basin: Distribution and Dynamics of Settlement

The paper deals with data on distribution of the alien fish species in the Dniester River basin since mid XX cent. To date, in the Ukrainian part of the Dniester basin 20 adventive species of 9 families have been recorded. The maximal number of alien species is of the East-Asian origin − 40%, the North-American group is presented by 30%, Ponto-Caspian − 15%, the endemics from the Danube basin form 15%. Invasion of most alien fishes to the Dniester River basin is a consequence of the active purposeful introduction of new species into aquaculture. The distribution of the adventive fish species in different parts of the Dniester River basin is conditioned by hydromorphological conditions, among which the flow velocity and character, composition and mobility of the bottom sediments, the presence of the higher aquatic plants thickets are the most important. Based on the analysis of the long-term data, characteristic of the most abundant alien fishes in the upper, middle, and lower Dniester basin sections have been identified. The long-term dynamics of the alien fish species introduction into the Dniester river basin were analyzed.