Acoustic receiver array in the Gudena River, Denmark, from 2005-2005

The population of European silver eel (Anguilla anguilla) has declined tremendously in the last decades. The cause of this decline is unknown, and it is necessary to investigate the migratory behaviour and survival rates of silver eels during the reproductive migration in order to understand if the decline is related to factors acting during that migration. We estimated survival and progression rates of European silver eel migrating in the lower part of the River Gudenaa and during the first phase of the marine migration in the Randers Fjord in Denmark.  Migration was monitored using an array of 14 Innovasea (VR2) acoustic receivers distributed accross 10 stations. Progression rate and mortality in the river, inner part of the fjord and outer part of the fjord were estimated.