COMPARISON OF NEMOPILEMA NOMURAI AND OTHER JELLYFISHES IN REPRODUCTIVE BIOLOGICAL CHARACTERISTICS AND MORPHOLOGY
中国北部海域灾害水母沙蜇(Nemopilema nomurai)及其它钵水母繁殖生物学特征与形态比较

To clarify the causes for the mass occurrences of Nemopilema nomurai, the multi-million scyphistomae were obtained by natural fertilization, using N. nomurai as parent body from the northern Yellow Sea. The stages of N. nomurai from planula, scyphistoma, strobila and ephyra to young medusa were observed under laboratory conditions, the life cycle of N. nomurai was compared with earlier findings of the life cycle of C. nozakii,C. capillata, A. aurita, Rhopilema esculentum, R. hispidum, Rhizostoma pulmo and Stomolophus meleagris. For A. aurita and C. capillatamedusae, fertilization occurred in the gastrovascular cavity and gonad of female, others of them in the water. Planulae of C. nozakii could form planulocysts prior to forming a scyphistoma. C. nozakii and C. capillatacould produce podocysts and a stolon, However, N. nomurai, R. esculentum, R. hispidum and S. meleagris, and N. nomurai(Kawahara et al, 2006) only produced one type of cysts: podocysts. In addition the scyphistoma of A. aurita might further produce polyps by producing podocysts, direct buding, formation of stolon, longitudinal fission, internal production of free-swimming propagules, external production of free-swimming propagules and direct development from planula to single ephyra. The asexual reproduction of Rhizostoma pulmo included producing podocysts, buding, formation of stolon and planuloid buds.