Diversion of eel by means of air bubbles in the river Overijsselse Vecht, Netherlands

At three locations in the large rivers in the Netherlands hydropower plants are in use which damage the fish population, mainly eel. One of the options to decrease the damage is to divert the eel from the inlet systems and to guide them past the plant via a bypass. Near one of the plants, in the river Overijsselse Vecht, nets and fykes are placed. An air bubbles screen is installed on the bottom of the river to deter the downstream migrating eel and to divert them to the fykes alongside the river bank. No eel could be deterred by the screen. It even appeared that circa 9% of the downstream migrating eel was slightly attracted by the air bubbles