Pikeperch (Sander lucioperca) (n=43) were tagged with acoustics transmitters in Lake Peipsi (Estonia) to track their migrations within the Lake Peipus complex and River Emajõgi using and array of stationary receivers deployed to the sounds between lakes and to River Emajõgi. The tagged fish were tracked for three years to identify: 1) their migration patterns; 2) which parts of the system are most used for feeding and which for spawning. The ultimate goal was to provide advice to the management for stock assessment.