Piotr Dębowski
ABSTRACT. The article presents the results of the third year of monitoring the fishway in the Włocławek Dam on the Vistula River. The monitoring is being conducted with a Riverwatcher, VAKI, automatic fish counter. It recorded 23,028 fish migrating upstream in 2017. Vimba dominated with 11,000 individuals, followed by bream, white bream, asp, and barbel. The total number of fish was three times higher than in 2016 and six times that in 2015. The main differences were in the mass migration of vimba, white bream, and asp. Stocking of vimba and improved conditions for passing through the auxiliary dam below the main dam because of higher discharge were suggested as the causes of these differences. The fish migrated during the years monitored in spring and fall and usually intensively for short periods and sometimes a few times per season. These runs were analysed in relation to water temperature and discharge and changes in these parameters.
Key words: fish migration, fishway, fish counter, Włocławek dam, Vistula River
Przyjęto po recenzji 12.04.2018 r.