Ichthyological Evaluation of Fish Passes Constructed in Lithuania

Abstract

The current paper is a survey of fish passes built in Lithuania and a generalisation of the data on their efficiency collected during the period 1998–1999. At the present time, there are 11 fish passes in Lithuania, two of which are fish locks, three pool and orifice fish passes, three pool and weir fish passes, one Denil fish pass and two bay-pass channels. Two fish passes are at a standstill because of some technical faults. Three fish passes operate inefficiently. According to the data collected in 1998–1999, before the reconstruction, Tauragė fish lock provided a passageway for about 9% of vimba and 15% of sea trout, which had gathered at the dam during their spawning migration in autumn. In 1998 about 460 vimba and 220 sea trout ascended upstream through this fish pass, whereas in 1999 their number was 430 and 150 respectively. Through the fish pass of Anyksciai, only local spring spawners can get into their spawning grounds, since migratory fish species (vimba, sea trout, salmon, river lamprey) asce...