Movement and pattern of activity of the roach in the River Spree, Germany

Water body and bank structure use of adult roach Rutilus rutilus were examined to increase the knowledge of the most abundant species in the River Spree, Germany. Six tracking series were conducted between 1994 and 1995 to analyse the seasonal and diel movements of the fish. In each series, four to 12 roach were tagged externally and located every 2 h for up to 14 days using radiotelemetry. Roach were highly active, moving up to 10 km downstream to Lake Dämeritzsee, and up to 6 km upstream from their release site. The fish, which mostly swam greater distances upstream during the day and downstream at night, were most active during the spawning season. Their habitat range varied greatly. Close-range habitat, based on 50% of all radiolocations, varied between 5 and 1350 m (mean, ?=296 m). Wide-range habitat, based on 90% of all radiolocations, varied between 75 and 3820 m (?=1006 m). The fish preferred different sections of water at different times of year, casting doubt on the relevance of the term home range. Generally, roach stayed close to the bank structures of the main channel during the day and moved to the stagnant waters at night. Consequently, they were most active at dawn and dusk.