ABSTRACT. The article presents results of the fifth year of monitoring of the fishway in the Włocławek dam on the Vistula River. The monitoring has been carried by Riverwatcher, VAKI, automatic fish counter. Hydrologically the year was untypical with low year average flow, lack of spring surges and high water in end of May, later than usual. 11 676 fish migrating upstream have been recorded; mostly vimba, 8244 fish, and white bream, 1410 fish. Twenty two species have been recorded, more than for the previous four years in total; some of them for the first time: white-eye bream, Prussian carp, and nase. That is interpreted as a result of untypical hydrological regime. High variability in number and species composition of migrants related strongly to hydrology suggests that the Włocławek dam still constitutes important migration barrier.
Key words: fish migration, fishway, fish counter, Włocławek dam, Vistula River
Przyjęto po recenzji 10.08.2020 r.