Thursday, January 19, 2006; Posted: 4:24 p.m. EST (21:24 GMT)

TOKYO, Japan (Reuters) — A slimy jellyfish weighing as much as a sumo wrestler has Japan’s fishing industry in the grip of its poisonous tentacles.

Vast numbers of Echizen kurage, or Nomura’s jellyfish, have appeared around Japan’s coast since July, clogging and ripping fishing nets and forcing fishermen to spend hours hacking them apart before bringing home their reduced catches.
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“It’s a terrible problem. They’re like aliens,” Noriyuki Kani of the fisheries federation in Toyama, northwest of Tokyo, told Reuters ahead of the conference.
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One Echizen kurage can be up to 2 meters (6 feet, 7 inches) in diameter and weigh up to 200 kilograms (440 pounds).

Despite their size, the invertebrates aren’t toxic enough to cause serious harm to humans, but fishermen often wear goggles and protective clothing to avoid stings when dealing with them.

Much about the jellyfish, the largest variety found in the Sea of Japan, remains a mystery, according to Hitoshi Iizumi of the Seikai National Fisheries Research Institute in Niigata.

Researchers have suggested they drift to Japan on currents after reproducing in South Korean or Chinese waters, a theory that Japan wants to investigate with the other two nations.
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Spikes in population have occurred in the past, notably in 1958, but consecutive outbreaks in 2002 and 2003 prompted the government to seek reasons and solutions.

Scientists have suggested global warming might be a factor.
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Officials at Thursday’s conference are also set to propose a forecasting system that would allow fishermen to prepare for the next onslaught of the jumbo jellyfish.

South Korean fishermen have been suffering similar woes, but China, where giant jellyfish are a delicacy often served dried and dressed with sesame oil, does not seem to have registered the outbreak as a major problem, Japanese officials said.