Biological characteristics of the european Platichthys flesus in the top of the estuary of the Tuloma River

The results of seasonal studies of the ichthyofauna carried out at the top of the estuary of the Tuloma River in April, June, September and October 2018–2020 are presented. The dominant species in the water area is the European flounder; its abundance in net catches increases from April to September. Distribution density in September 2020 varied from 13 to 1667 ind/ha, biomass – from 0.013 to 276.9 kg/ha. European flounder in the study area in the spring-summer period is represented mainly by juveniles from 15 to 18.5 cm long. In autumn, six- to seven-year-old individuals with a size group of 22–24 cm were recorded. The age of European flounder in the area did not exceed 8+ years. The sexual structure, stages of gonadal maturity and nutrition of the European flounder are also considered.