A 12-year study of the upstream migration of Anguilla anguilla in a fish-pass in the river Meuse reveals a dramatic decline of the stock in Belgium.

From 1992 to 2004 upstream migrating eels were collected in a trap (0,5 cm mesh size) installed at the top of a small pool-type fish-pass at the Visé-Lixhe dam (built in 1980 for navigation purposes and hydropower generation; height : 8,2 m; not equipped with a ship-lock) on the international River Meuse near the Dutch -Belgium border (290 km from the North Sea; width: 200 m; mean annual discharge: 238 m3/s; summer water temperature 21-26°C).The trap in the fish-pass was checked continuously (three times a week) over the migration period from March to September each year, except in 1994. We ca... Mehr ...