Jellyfish most are nowhere near that large). They have a moderately painful, but rarely fatal, sting. The increasingly common giant Nomura's jellyfish, "Nemopilema nomurai", found in some, but not all years in the waters of Japan, Korea and China in summer and autumn is another candidate for "largest jellyfish", in terms of diameter and weight, since the largest Nomura's jellyfish in late autumn can reach in bell (body) diameter and about in weight, with average specimens frequently reaching in bell diameter and about in weight. The large bell mass of the giant Nomura's jellyfish can dwarf a diver and is nearly
Jellyfish injury or even death; small box jellyfish are responsible for many of these deaths. When conditions are favourable, jellyfish can form vast swarms. These can be responsible for damage to fishing gear by filling fishing nets, and sometimes clog the cooling systems of power and desalination plants which draw their water from the sea. The name jellyfish, in use since 1796, has traditionally been applied to medusae and all similar animals including the comb jellies (ctenophores, another phylum). The term "jellies" or "sea jellies" is more recent, having been introduced by public aquaria in an effort to avoid use of