摘要：The seasonal population dynamics and feeding preferences of the moon jellyfish, Aurelia aurita, in the Gulf of Gdansk (southern Baltic Sea) were investigated. Medusae were present in the water column from June to November, with maximum occurrence in August and September. The medusa bell diameter and weight increased during the study period reached maximum values in October. The relationship between bell diameter and wet weight was strong. No ephyrae were observed during the study period. Gastric content analysis revealed that the medusae fed mainly on copepods and cladocerans. Rotifers that dominated the water column throughout the study period were not found in the jellyfish guts, but the stable isotope signature indicated that they could have been a significant source of derived carbon. Low numbers of plankton prey and the lack of fish larvae in A. aurita guts suggest that the jellyfish is of minor relevance as a predator and competitor in the Gulf of Gdansk.
