Fish Species of the Red Data Book of Ukraine in the Dnieper-Bug Estuary and the Lower Dnieper in the Modern Period

The paper presents results of research of ichthyological surveys in the Dnieper-Bug estuary and the lower Dnieper for the 30-year period (1992-2021). Over this period, 15 fish species were recorded listed in the Red Data Book of Ukraine (2009). Two of them (13.3%) were recorded in the considered water areas for the first time and are obligatory marine species. The occurrence degree of the protected fishes was established. According to the principle of occurrence and records in these water areas, they were conditionally divided into three categories: 1) permanently occurring; 2) migratory, which enter annually or almost annually; 3) rare or only once detected. The localization of these species in the considered region was determined. One of the species is considered critically threatened, and one species has vanished since 1992. The material presented is especially actual in view of consequences of the catastrophic events after the Kakhovka Dam (Hydroelectric Power Plant) destruction owing to expected drastic changes of ichthyofauna of the Dnieper estuary in the coming years.