The invasive Chinese mitten crab is a freshwater species, however, for its reproduction it is dependent on salt water. Therefore, adult Chinese mitten crabs migrate during autumn from their freshwater habitat towards the sea via the River Scheldt. Through acoustic telemetry we hope to uncover the timing of this migration, their migration speed and the timing and place of reproduction (does it take place in the Scheldt Estuary or in the North Sea?). This information is valuable to have a better understanding of the ecology and lifecycle of this species in its invasive range, but could possibly be used for management purposes as well.