What’s 6 feet wide, weighs 440 pounds, and can ruin your whole day? If you’re a Japanese fisherman, the answer is Nomura’s jellyfish (Nemopilema nomurai), or, as the Japanese call it, echizen kurage.

The gigantic creature can wreak havoc on fishing nets and their contents, destroying the nets and poisoning the catch. Even nuclear powerplants aren’t safe: Reports describe the jellyfish being sucked into pumps that draw seawater to cool the reactors.

Echizen kurage have shown up in Japanese waters in increasing numbers in recent years. The population surge of 2005 was particularly bad, affecting the salmon, yellowtail, and anchovy fisheries. But the mass of them gathering now in the Yellow Sea off China is the biggest ever, and eventually ocean currents will deliver them to Japan’s doorstep.

The reasons for the exploding population are not clear. Theories range from agriculture runoff to overfishing to global warming. As for fighting the jellyfish, methods are few and far between. In fact, when under attack, the creatures release millions of sperm or eggs, all with the potential to grow more jellyfish.

There have been efforts to make the most of this plague by creating jellyfish products. Some of them are edible, including ice cream and even cookies. Echizen kurage is also a source of collagen, which can be used in cosmetics.

But the jellyfish invasion in store for Japan this time around is likely to deliver more raw materials than any such efforts could possibly keep up with. The result could be devastation for much of Japan’s fishing industry.

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By DanBing on 22-07-2009