AVERAGE BIOLOGICAL INDICES OF THE MAJOR FISH SPECIES OF THE ZAPORIZHZHIA RESERVOIR AND OTHER FISHERY WATER BODIES OF DNEPROPETROVSK REGION

Purpose. To investigate, analyze and summarize the biological indices of commercial fish species in the main fishery water bodies of Dnіpropetrovsk region for the last 10 years. Methodology. Field data were collected in the Zaporizhzhia reservoir during 2003 ? 2013 using a standard set of monitoring fishing gears (gill nets with mesh size a=30?120 mm). Juvenile fish were caught in third decade of June - first decade of August using the juvenile fish beach seine with a length of 10 m. Processing of ichthyological materials was conducted according to generally accepted methods. Findings. When comparing the biological indices of fish in the Zaporіzhzhia reservoir with the data for the past decade reflected in the normative documents, we found significant changes in the population of pikeperch and gibel carp, which concern the average fish weight, fertility and the relative proportion of females in the spawning stock. Roach, perch, and gibel carp are characterized a reduced number of spawning events. The biological indices of bream, common carp, pike and catfish populations remain virtually unchanged during the study period. As for biological indices of Black and Caspian Sea sprat, rudd, gobies and crayfish, the information on these species in the relevant regulatory documents is missing, so it is not possible to assess the dynamics of their changes. Due to an inventory of small fishery water bodies we received the information on the biological indicators of major species, which can also be used for updating the normative database. Originality. For the first time we summarized the characteristic of fish fauna in major fishery water bodies of Dnepropetrovsk region and analyzed main indices, which define the conditions of fish stock development and exploitation of aquatic living aquatic resources in fishery water bodies. Practical Value. Materials of the work can be used for adjusting the existing regulations in available ichthyology and fisheries management techniques, as well as for determining the allowable amounts of commercial fish catches in the Zaporіzhzhia reservoir.