Characteristics of spawning migration of fish in the rivers of the Curonian Lagoon basin on the example of the Promyslovaya River

The assessment of the spawning migration of fish in the Promyshlovaya River was carried out on the basis of an integrated approach, including the joint use of sonar complexes and control catches with set of fixed nets and smooth nets in the spring period during the study period. The ichthyocenosis of the Promyslovaya River is represented by 20 species, the basis of which is bream, roach, silver bream, ruff and bleak. In 2021, roach and silver bream account for size groups from 8 to 20 cm. Among fish with a length of 23-28 cm prevail roach, bream, vimba and perch. Bream prevails in size groups of more than 28 cm. Mass spawning migration is observed when the water is heated above 12 °C In 2022, there was a decrease in the size range and the dominant size groups. In 2021, the main migration activity occurred at twilight and night, and in 2022 migration was more smooth. In 2022, there was an almost twofold decrease in the total number of passing fish compared to 2021 due to a significant drop in the number of migrating bream, due to changes in spawning conditions in the estuarine and estuarine parts of the river and bay.