Life cycle of the jellyfish Rhizostoma pulmo (Scyphozoa: Rhizostomeae) and its distribution, seasonality and inter-annual variability along the Catalan coast and the Mar Menor (Spain, NW Mediterranean)

20 pages, 8 figures, 5 tables

Rhizostoma pulmo is one of the most abundant scyphomedusae along the Mediterranean coasts. To understand changes in the population densities of the medusa stage and its relationship with the benthic stage, we describe all developmental stages from the life cycle of R. pulmo, from the scyphistoma stage to young medusae reared in the laboratory. Mature scyphistomae showed a mean total body length of 1.7 mm and the average tentacle number was 16. Asexual reproduction occurred by lateral budding, podocyst and pedalocyst production. Each strobila released up to 8 ephyrae that had a mean total body diameter of 3.5 mm. Moreover, we also present data on the temporal and spatial distribution of the species in the Catalan Sea and the coastal lagoon on Mar Menor (NW Mediterranean) during the years 2007–2009. In the Catalan Sea, the presence of adult R. pulmo was recorded as extended along the whole coast, but most of the observation was concentrated in the central area; the highest abundances were recorded during the months of July and August. The highest number of observations was detected in 2008 in coincidence with the inter-annual variation observed in the Mar Menor lagoon

We thank the Catalan Water Agency for funding the Medusa Project. We are indebted to all institutions collaborating with the reporting network. Furthermore, we would like to thank PD Dr. G. Jarms (Hamburg, Germany) for kind advice and laboratory facilities. We also thank the Regional Government of the Region of Murcia (Comunidad Autónoma de la Región de Murcia—CARM) that financed the monitoring programs in the Mar Menor and to the EUROGEL European project that financed sampling there in 2003–2005. We thanks also Eduardo Ovis and Georgios Tsounis for the photographs of the jellyfish

Peer reviewed