A fish pass construction program has started some twelve years ago in France. Some of these passes have been monitored to test their efficiency, to acquire biological data on migratory fish and to perfect knowledge of fish passes design criteria. The paper presents the various techniques followed in these surveys: fish counting techniques, including conventional methods such as trapping or automatic resistivity fish counters and recently, more sophisticated techniques such as video recording and behavioral studies of fish by telemetry. Telemetric studies have been conducted on three migratory species: Atlantic salmon (Salmon salar), sea trout (salmo trutta trutta), allis shad (Alosa alosa). The advantages, drawbacks, field of application and cost of each techniques are discussed. (author). 16 refs., 7 figs., 1 tab.