Abstract:

Substantial changes in the hydroecosystem of the Zaporizke reservoir have led to a significant transformation of aquatic biocoenoses. As a result, number of some aboriginal fish species have decreased. The regulation of the Dnipro river has contributed to the spread of new species of fish. Over the past 30 years, the ichthyofauna of the reservoir has gained about 20 species of fish that acclimatized and expanded their range. The article presents the results of ichthyological research of 2010- 2016. The article determines main causes of the spread of new species of fish, and gives the results of complex monitoring studies on the number and biomass of young alien fish species of the Zaporizke reservoir. It was found that the most numerous first summer individuals of alien fish species are big-scale sand smelt Atherina pontica (Eichwald, 1831), Prussian carp Carassius gibelio (Bloch, 1782), topmouth gudgeon Pseudorasbora parva (Temminck et Schlegel, 1846), black-striped pipefish (Syngnathus abaster Risso, 1826) and pumpkinseed Lepomis gibbosus (Linnaeus, 1758).

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