Identification key for young ephyrae: a first step for early detection of jellyfish blooms

Although jellyfish blooms are a focus of recent research, the roles that the developmental stages of species play are underestimated. Planulae, polyps and ephyrae are inconspicuous and often overlooked. The importance of production of ephyrae from the sessile polyps has become more apparent. Our objective was to establish an identification system for early ephyrae of scyphozoan species in plankton samples. We studied ephyrae of 18 species. Standard measurements were introduced and the variability of marginal lappets analysed. Characters differentiating the 18 species are described. Photographs and drawings of each species are presented as a catalogue of ephyrae of these species. We developed a key for identification of the 18 species.