The purpose of this study was to determine whether or not artificial freshets affect the upstream spawning migration of brown trout at upper and lower Finsjö in the river Emån in southeastern Sweden. By changing the flow of water in the residual stretch and monitoring radio and PIT -tagged fish through automatic scanning stations it was possible to analyse if there was any correlation between the flow and migration. The purpose of releasing freshets in the bypass channel was to make the fish migrate through the bypass channel rather than swimming into the hydroplant channel. Four freshets were released with low flow periods in between, the first three freshets were of short duration and low flow whereas the fourth was large and long. The first three showed no effect on migration but the fourth freshet did. Due to a high overall flow of water during the fourth freshet it was not possible to distinguish between flow in the bypass channel and overall high flow. The results suggested that high flows are probably needed for fish to become motivated to migrate. Once the fish is motivated and migrates, freshets or some kind of high flow in the bypass channel is probably needed to attract the fish into the appropiate channel.