Gigantic jellyfish invade the Sea of Japan



Outbreaks of Nomura's jellyfish off the coast of Japan have caused trouble for local fishermen/
Copyright (c) 2003 Y. Taniguchi, Niu Fisheries Cooperative

First it’s the swarm of jumbo flying squid off San Diego, then there’s a giant black fibrous, hairy blob off of Alaska, and which turned out to be an unknown algae, which even the native Inupiat Eskimo elders had never seen in their lifetimes. Now I hear of a population explosion of gigantic Nomura’s jellyfish off Japan.  What is going on with our world’s oceans? Some changes are afoot!

After reading my blog post, an environmental journalist colleague said he thought squid were gross. “Gross? No way!” I replied,  “I got squirted in the face by their squid ink, and I still think they're not gross.”  He then asked if I’d heard of the giant jellyfish invading Japan, “Now, they really are gross, no?”  I replied, “They are spectacularly cool. I am an animal lover! I love all kinds of creepy, slimy, poopy things.”  What can I say?

But I digress. Back to the facts about the Nomura or Nomura's jellyfish (Nemopilema nomurai), also known as the Echizen jellyfish. For the sixth year since 2002, these huge creatures that grow to six feet in diameter and can weigh 450 pounds have shown up by the hundreds of thousands in the Sea of Japan, brought in by oceanic currents from the Yellow Sea. They’re more than just a scientific anomaly; they’re causing serious problems for rural Japanese fishermen because they get entangled in their giant nets, destroying the nets and their catch.

Since the first jellyfish invasion in 2002, Japan instituted a warning system so that fishermen now know the jellyfish are in the waters and can save their expensive nets, but they still lose money they’d get from fishing. The invasion has impacted whole coastal communities. "In the high season of Nomura's Jellyfish, more than 1000-5000 big jellyfish are unwantedly caught in the set-net, more than 100 tons for one day," explains Kiminori Ushida, a scientist with Riken Advanced Science Institute who studies the jellyfish. "Fishermen want to just remove [the jellyfish] from the inside of set-net but they cannot take out them from water because the bulk is too heavy."

Scientists don’t really know what has caused the change since 2002, but several possibilities exist. CSIRO Climate Adaptation Flagship and University of Queensland scientist Dr. Anthony Richardson and colleagues recently published research in Trends in Ecology and Evolution discussing reasons for the general increases in certain jellyfish worldwide. Overfishing could have depleted the fish that prey on the tiny jellyfish released from their polyp stage, leading to a population boom of the adults. Or, warming ocean temperatures, pollution, or an increase in artificial reefs along the coastline could be to blame. More research is needed to find out.

Since the first invasion of the giant jellyfish, some Japanese scientists have also studied what could be done with them. Ushida and colleagues isolated a mucin-like glycoprotein from the jellyfish they named qnuimucin or Q-mucin. "I took this mascot name from Japanese word Kuni-Umu, meaning rebirth of the community or country," says Ushida. Mucins lubricate body surfaces and have antibacterial properties, and the jellyfish mucins are similar in chemical composition to human mucins. In contrast to mucins from pigs and cows, currently used, "jellyfish mucin is very simple, well-defined and easy to be purified, having an advantage of suitability to material sceence and engineering," says Ushida.

One company, Tango Jersey Dairy, has decided to take advantage of the mass jellyfish invasion to make something edible – jellyfish ice cream. I’d be willing to try it… though it sounds gross. Would you eat jellyfish ice cream? And when it comes to jumbo squid, or giant jellyfish, what’s your verdict – cool or gross?

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