

A diver swims near a school of giant jellyfish in the Sea of Japan off Echizen, Japan, on Oct. 31. The jellyfish in the school measure nearly three feet in diameter. Local fisherman said the jellyfish are actually smaller this year, but are present in huge numbers. Newscom
A large jellyfish and a diver are seen off the Medas Islands in Spain. Newscom
A diver attaches a sensor to a large Echizen jellyfish off the coast of Komatsu, Japan. Yomiuri Shimbun/AFP/NEWSCOM
A giant jellyfish is seen off the coast of California. NEWSCOM
A giant jellyfish in the Pacific Ocean is seen with juvenile crabs on it. NEWSCOM
A diver swims with a giant jellyfish, identified as a Stomolophus nomurai, off the coast of Japan. The jellyfish is more than three feet in diameter and can weigh as much as 330 pounds, according to a local fisheries official. Tetsuji Asano/Ashai Shimbun/AP/FILE
A large jellyfish is seen off the coast of Israel in this April 2007 file photo. B. Galil/AFP/NEWSCOM/FILE
A diver documents a giant jellyfish in the Pacific Ocean off California. Newscom
A large brown jellyfish is seen near Shizuoka, Japan. NEWSCOM
Two giant Echizen jellyfish are seen swimming in the Sea of Japan. NEWSCOM