Species composition and distribution of early juvenile fish in the period of sloping migrations in the middle course of the Oka River
2021
Bykov, A.D.
The aim of the work is to conduct research to assess the natural reproduction of fish in the channel zone of the Oka River in the summer of 2019 within the boundaries of the Ryazan region. Methods used: when collecting material on the ramp of fish larvae, the method of drift accounting using ichthyoplankton traps was used. Novelty: for the first time during the period of ichthyological studies in the middle course of the Oka, accounting surveys were conducted to assess the species diversity of fish at early stages of development. Based on the results of accounting for early juvenile fish during the period of rolling migrations, the species structure and quantitative indicators of the concentration (ex./100m3) of ichthyoplankton in the river drift were established. The issue of the occurrence of individual species and ecological groups of early juvenile fish is considered depending on the hydrological indicators of river biotopes of the riverbed, compared with the results of previous studies conducted on the upper reaches of the Oka River in 2015. The interrelation of the species structure and the size of catches with the flow velocity and depth of setting of ichthyoplankton traps is shown. Practical significance: based on the species structure and quantitative indicators of ichthyoplankton concentration in the river drift, it is possible to predict the dynamics of the number of commercial fish species in the mold and rolling areas of the middle Oka River
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