During the last decades, the ecological importance of jellyfish has been increasingly recognized because their outbreaks have been reported frequently in many parts of the world’s ocean andmany species seem to be undergoing range expansions into new areas. Life cycles studies of the most important blooming species are necessary since they provide important clues for understanding jellyfish distributions and interannual fluctuations. In the NW Mediterranean coasts blooms of several jellyfish are frequently observed, being Rhizostoma pulmo the most abundant. The life cycle of R. pulmo has been studied starting from mature medusae, which are kept in continuous culture condition on the Marine Science Institute in Barcelona, Spain. All stages in the life cycle were reared in the laboratory (from planulae to young medusae). Mature scyphistomae had a mean total body length of 1.69 mm, a mean oral disc width of 0.70 mm and the average tentacle number was 16. Asexual proliferation occurred by typical lateral budding at the junction point of calyx and stalk lateral budding by means of stolo, and podocyte production. Each strobilae liberated up to 13 or 15 ephyrae at 14ºC or 28ºC respectively. Newly liberated ephyrae had a mean total body diameter of 3.52 mm and a central disc diameter with a mean value of 1.47 mm. The development of the gastric system of the ephyrae and juvenile is also described. We discuss the temporal and spatial distribution of the species along the Catalan coast in relation with the observed life cycle patterns

Third International Jellyfish Blooms Symposium, 13-16 July 2010, Mar de Plata, Argentina

Peer Reviewed