Jellyfish several countries; jellyfish caused a cascading blackout in the Philippines in 1999, as well as damaging the Diablo Canyon Power Plant in California in 2008. They can stop desalination plants and ships' engines. Jellyfish Jellyfish or sea jellies are the informal common names given to the medusa-phase of certain gelatinous members of the subphylum Medusozoa, a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animals with umbrella-shaped bells and trailing tentacles, although a few are not mobile, being anchored to the seabed by stalks. The bell can pulsate to provide propulsion and highly efficient locomotion. The tentacles
Jellyfish jellyfish, "Stomolophus meleagris", along the southern Atlantic coast of the United States and in the Gulf of Mexico for export to Asia. Jellyfish are also harvested for their collagen, which is being investigated for use in a variety of applications including the treatment of rheumatoid arthritis. Aristotle stated in the "Parts of Animals" IV, 6 that jellyfish (sea-nettles) were eaten in winter time in a fish stew. In some countries, such as China, Japan, and Korea, jellyfish are a delicacy. The jellyfish is dried to prevent spoiling. Only some 12 species of scyphozoan jellyfish belonging to the order Rhizostomeae are