Nomura's jellyfish are swarming the waters of the coast of Chiba. (Map: Stock File)

Trawler capsized by giant jellyfish

JAPAN
Wednesday, November 04, 2009, 03:00 (GMT + 9)

The 10-tonne trawler Diasan Shinsho-maru capsized off the coast of Chiba as its crew attempted to haul in a net containing dozens of Nomura's jellyfish (Nemopilema nomurai). Burgeoning amounts of these animals have become an unprecedented plague in Japanese waters since their numbers began to swell earlier this year.

The three-man crew was tossed into the sea when their vessel capsized; to be later rescued by another trawler. The weather was clear and the waters calm at the time of the accident, the local Coast Guard office stated, The Telegraph reports.

Each of the jellyfish can weigh up to 220kg and measure as much as 2m in diameter. Weather and water conditions in the breeding grounds off the Chinese coast, according to experts, have provided an ideal habitat for the reproduction of Nomura's jellyfish in recent months.

Nomura’s jellyfish currently swarm the Yellow Sea off China, the Korean peninsula and the Sea of Japan, FOX News reports.

"The arrival is inevitable," said Professor Shinichi Ue of Hiroshima University. "A huge jellyfish typhoon will hit the country."

They caused similar problems for Japan in the summer of 2005, when they damaged nets, caused fishers injuries, and left fish poisoned.

Not much is known about the species. Experts have not been able to determine the reason why thousands of the jellyfish swarm the Sea of Japan on the Tsushima Current on some years, while other years present small quantities of the animals or none at all.

In 2007, there were reports of 15,500 incidents of damage to fishing equipment caused by Nomura’s jellyfish.

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A possible contributing factor to the expanding population of these animals around Japanese waters, according to experts, is a dip in the population of jellyfish predators, such as sea turtles and certain species of fish.

Other possibilities include more hospitable breeding grounds due to warming waters caused by climate change and effluent from Chinese rivers containing nutrients that serve as food for the jellyfish.

Related articles:

- Jellyfish invasion imminent
- Jellyfish plague the Southern and Yellow Seas

By Natalia Real
editorial@fis.com
www.fis.com