Wetenschappelijke onderbouwing en ondersteuning van het visserijbeleid en het visstandbeheer

Abstract

An important migration barrier for glass eel near Oostende is the pumping station Kwetshage-Paddegat. It is situated where the Jabbeekse stream and channel Gent-Oostende meet. This station pumps the polder which is of great ecological value for young eel and has a good water quality. Currently it is not accessible for glass eel. Last year the best location to build a glass eel ladder was studied. In 2022 we build and evaluated an experimental construction to allow glass eels and elvers to enter the polder without human interference. 60 glass eels and 1449 elvers were caught at the end of the pipe construction. The migration peak was, just as last year, situated in the second half of May. There were problems with the catch bin and we think a part of the entering eels escaped, leading to an underestimation of the amount of elvers. Apart from this, the glass eel ladder and pipe construction seem to work properly. Research on the intake of glass eel and elvers near the watermill in RotselaarThis migration barrier was solved a few years ago with the installation of a fish passage. Now that the barriers in Leuven are dealt with too, the Dijle should be fully accessible for fish in Flanders. Recent research, however, showed that glass eels and elvers rarely use the fish passage. Most of the young eels accumulate in the watermill pool, searching the entrance of the fish passage. In 2022 only 5 elvers were caught with the glass eel ladder and none with the artificial substrates. The substrates washed away twice when debris was flushed. The summer was very dry, leading to a water level lower than usual. The glass eel ladder was on a regular basis not available for the young eels. This lasted only for a couple of hours a day. We don't think this is the reason for the low numbers caught. This is much rather due to the attractability of the flush on the glass eel ladder. Research on the intake of glass eel and elvers from the Yser to the basin of Stenensluisvaart and Blankaart/