Giant Jellyfish Invade Japan

Since last summer, Japanese waters have been inundated with the massive sea creatures, which can grow 2 meters wide and weigh up to 200 kilograms. The spread of such giant jellyfish is causing a crisis in the local fishing industry as they are being caught in the fishing nets and poisoning the fish. The poison of such jellyfish can easily kill a person, but insofar reports of serious human injuries and deaths have been rare.

Jellyfish are more common in Chinese and Korean waters but recently they have spread to Japan as well. The Japanese scientists have now begun to study this animal more properly to better understand its mating and migration habits.

Jellyfish are invertebrates. The body of an adult jellyfish is composed of a bell-shaped, jellylike substance enclosing its internal structure, from which the creature's tentacles suspend. Each tentacle is covered with stinging cells that can stun or kill other animals, either for securing prey or as a defense mechanism. Most jellyfish are passive drifters that feed on small fish and plankton which become caught in their tentacles.

The jellyfish doesn't have any basic sensory organs or a brain, although it has a very primitive nervous system. It can perceive stimuli, such as light or odor, and orchestrate immediate responses, but these data are not centrally collected.

The cause of the current invasion is not known. Some scientists believe that unusually heavy rains in the Yangtze River Delta region in China may have created an overflow that is carrying the jellyfishes to Japan. Another possibility is that global warming has slightly increased the sea temperature attracting more animals into Japanese waters. It is speculated that warm waters may favor their multiplication.

The image above is a National Geographic picture of a diver attaching a tracking device to a giant jellyfish off the coast of Japan.

As the research continues, Japanese fishermen have to wonder what to do with all the caught jellyfish. So far, resourceful fishermen have turned their unwanted catch into crab food, fertilizer, and novelty snacks-served dried and salted. The chilled Jellyfish arm is a common type of appetizer in the Shanghai-style Chinese cuisine as well as in Vietnam.