This is an acoustic telemetry dataset published by the Research Institute for Nature and Forest (INBO). It contains animal (fish) tracking data collected by the Permanent Belgian Acoustic Receiver Network <a href=\"https://lifewatch.be/en/fish-acoustic-receiver-network\">(https://lifewatch.be/en/fish-acoustic-receiver-network)</a> for the project/study 2014_demer, using VEMCO tags (V7, V13) and receivers (VR2W). In total 16 adult individuals of four local wild fish species (<i>Petromyzon marinus</i>, <i>Rutilus rutilus</i>, <i>Silurus glanis</i>, <i>Squalius cephalus</i>) were captured, tagged and released in 2014, to study the effect of a specific barrier on their upstream/downstream migration in the Demer basin.