The Chrysochromulina polylepis bloom in Skagerrak in May 1988 had severe consequences for the sea farming industry. Following the unexpected occurrence of the bloom combined remote-sensing and model studies of the mesoscale circulation of the Norwegian coastal current were performed in support of the daily forecasts of the advance of the algal front. A passive tracer included in the model simulated the drift path of the algae demonstrating the impact of meanders and eddies. Qualitatively the results of the simulation were in good agreement with the direct observations until the bloom culminated, suggesting dominance of the physical processes. In contrast, biological processes lead to the algal mortality during the retreat.