Nomura's jellyfish

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iNomura's Jellyfish

Scientific classification

Kingdom:	Animalia
Phylum:	Cnidaria
Class:	Scyphozoa
Order:	Rhizostomae
Family:	Stomolophidae
Genus:	Nemopilema
Species:	N. nomurai

Binomial name

Nemopilema nomurai
(Kishinouye, 1922)

Nomura's jellyfish (Nemopilema nomurai) is a very large Japanese jellyfish. Known in Japanese as echizen kurage (エチゼンクラゲ), it is one of the largest species of jellyfish.

Image link: [1]

1 Biology
2 Human impact
3 Taxonomy
4 References
5 External links

[edit] Biology

Growing up to 2m (6 ft 7 inches) in diameter and weighing up to 200kg (440 lb), Nomura's Jellyfish reside primarily in the waters between China and Japan, primarily centralized in the Yellow Sea and East China Sea where they spawn.

[edit] Human impact

While stings of this large jellyfish are painful, they are not usually toxic enough to cause serious harm in humans. However, the jellyfish's sting has been reported as fatal in some cases by causing a build-up of fluid in the lungs. As a precaution, fisherman encountering these jellyfish wear eye protection and protective clothes. To date there have only been eight reported deaths from the Nomura's sting.

The most recent problems first became obvious in late August 2005 when Japanese fishermen fishing for squid, anchovies, salmon and yellowtail began finding huge numbers of the jellyfish in their nets. Often, the weight of the echizen kurage broke the nets or crushed other fish in the net. In the worst cases, as many as 1000 Nomura's jellyfish have been trapped in one net [2]. Any fish trapped within the net with the jellyfish that survive were too poisoned and slimed by the tentacles to be of commercial value.

The areas that were known to be hardest hit were the Sea of Japan coasts of Fukui and Shimane prefectures in western Japan.

In some places, jellyfish density is reported to be "one hundred times higher" than normal, without explanation. There was a previous spike in the population recorded in 1958 and in 1995. There have been widely disseminated theories as to the cause of the population increase, but no definite explanation. One such theory is that development of ports and harbors along the Chinese coast have provided an increase in structures for the Nomura larvae to attach themselves to. Another is that the seas off of China have been inundated with nutrient-rich run-off from farms and industry. Yet another is that China has over-fished their waters and reduced the populations of the jellyfish's natural predators, which fed on the larvae while they are still zooplankton. A final possibility is global warming which would cause the heating up of the seawater and encourage jellyfish breeding. However all such theories remain speculative, as no research into the cause has yet been conclusive.

In an attempt to utilize the jellyfish in a productive manner, coastal communities in Japan are doing their best to promote jellyfish as a novelty food, sold dried and salted.

Students in Obama, Fukui (Japan) have managed to turn them into tofu, and jellyfish collagen is reported to be beneficial to the skin.

The jellyfish population has become such a substantial problem for Japan that it has led the government to form a committee to combat the problem.

[edit] Taxonomy

In 2004, scientists M. Omori and M. Kitamura proposed that "Echizen kurage is a distinct species of the genus Nemopilema. We propose to revive the original name Nemopilema nomurai (Kishinouye 1922) from the more commonly used Stomolophus nomurai."^[1] Most scientific journal articles have started using the name Nemopilema nomurai, however the media still tends to use Stomolophus nomurai.

[edit] References

^ M. Omori and M. Kitamura (2004) Taxonomic review of three Japanese species of edible jellyfish (Scyphozoa: Rhizostomeae), Plankton Biol. Ecol. 51(1): 36-51.