peer reviewed ; During a study period of 26 months, twenty trout (26.0-57.0 cm FL; 198-1,685 g) were daily located from 16 to 466 days in a small stream of the Belgian Ardenne, the Aisne stream (tributary of the river Ourthe) in order to characterize their annual pattern of mobility. Daily movements were more frequent and longer during the spawning period (October-December) than at any other time of the year. Upstream migrations (max.: 25 km) generally occurred during October and the first fortnight of November and were triggered by a combination of Variations of water temperature and water level within a thermal range of 10-14 degrees C. Spawning activity (second fortnight of November until late December) took place in the Aisne stream (max. width : 10 m) or in its small tributaries. Trout surviving spawning undertook a fast (max.:9,200 m in 24 h) and precise post reproductive homing. From winter to summer, daily movements were shorter and mainly corresponded to changes of residences within a home range of which the size was proportional to the trout's size. In March and June, some trout made long upstream unidirectional migrations of which the biological signification is still unknown. These results are discussed within the context of life history strategies and management of trout populations.