A new record of the freshwater jellyfish Craspedacusta sowerbii in Northern Italy is reported. The medusae bloom occurred in a small oligo-mesotrophic artificial lake during July, 2009. At the time of sampling, the medusae were all immature, reached low density and showed feeding preference towards the Daphnia complex of species, the most abundant zooplanktonic species in the lake. Negative feeding selectivity towards small Rotifera was demonstrated. The occasional occurrence of a C. sowerbii bloom in this lake suggests the distribution range of this species may be largely underestimated, and its potential impact on the zooplankton community remains unknown.
freshwater jellyfish, exotic species