p. 91 - 102 ECOLOGICAL OBSERVATIONS ON THE JELLYFISH AURELIA AURITA (L.) POPULATIONS FROM THE BLACK SEA Marian-Traian Gomoiu Romanian Marine Research Institute Constanta Abstract On the basis of the data obtained during the 64th expedition of the R/V "Vitjaz" in the Black Sea, the author presents the structure of jellyfish Aurelia aurita populations per size-classes and the importance of these populations in the energetics of the pelagial ecosystems.