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12 Terrifying Facts About Jellyfish and Why They’re Taking Over

12 Terrifying Facts About Jellyfish and Why They’re Taking Over
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Some say that cockroaches, those survivalists par excellence, could inherit the earth. If they do, it’s likely they will be joined by jellyfish populating the oceans or whatever might remain of them. As scientistáLisa-ann Gershwin details in her book, “Stung! On Jellyfish Blooms and the Future of the Ocean,” jellyfish in vast (really vast) numbers are now showing up all over the world, from the Black Sea to the coasts of Britain, Israel and Brazil.

Jellyfish blooms are a lot more than a nuisance to beachgoers not inclined to swim in waves teeming with gelatinous blobs and tentacles that can sting and poison. What’s going on now, as Tim Flannery writes in reviewing Gershwin’s book in the New York Review of Books,áis nothing less than the jellification (a term used even by scientists) of the ocean with far-reaching consequences and in no small part due to human activity.

Fossils of this gelatinous marine animal are the oldest ever found. The notable upsurge in their numbers is a very recent development and downright alarming for several reasons.

1. For all that they lackábackbones, a heart, blood, a brain or gills and are about 95 water, jellyfish can kill. Theábox jellyfish,áChironex fleckeri, has a bell (the jellyfish’s head) that’s about a foot across, attached to 550 feet of tentacles. 76 people have died from contact since with the box jellyfish since 1884. As Flannery writes, “if just six yards of tentacle contact your skin, you have, on average, four minutes to live Ś though you might die in just two.”

2. Jellyfish are invertebrates but some, such as box jellyfish, can hunt medium-sized fish and crustaceans. The ox jellyfish does have some unique features that set it apart from other jellyfish: it has eyes witháretinas, corneas, and lenses and a brain that can learn, remember and direct complex behaviors (like swimming 21 feet per minute.)

3. Get enough jellyfish together and they can bring down a ship. That’s just what happened in November of 2009, when a net of gigantic jelly fish (the largest was 450 pounds) capsized a Japanese trawler and knocked its crew of three overboard. Millions of jellyfish also caused aámajor coal-fired power plant in the Philippines to shut down in December of 1999. They’ve also been clogging up the cooling systems of nuclear power plants in Japan and India since the 1960s.

4. Jellyfish are intrepid travelers. Stowed away in the ballast water of ships, jellyfish have made the journey from the U.S. east coast to the Black Sea and been responsible for the vanishing of anchovies and sturgeon ináBulgaria, Romania and Georgia. Jellyfish eat the eggs and young of anchovies as well as the same food of adult anchovies, who then starve to death.


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Photos from Thinkstock, Photo Credit: Bart Heird, Son of Groucho

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8:26AM PDT on May 21, 2014

thanks for sharing :)

7:25PM PST on Nov 17, 2013

Any jellyfish that can bring down a Japanese trawler (or a coal plant) is A-OK with me. That would be one less Japanese ship raping and polluting the oceans

4:45AM PDT on Oct 1, 2013

stay away from jellyfish ..

7:39AM PDT on Sep 30, 2013

Scary ...

8:01AM PDT on Sep 29, 2013

Sounds like a horror movie!

10:11AM PDT on Sep 27, 2013

pretty scary

1:04PM PDT on Sep 26, 2013

Really scary when you consider big enough numbers can bring down ships. As the article says our rapidly depleted oceans will be void of life...except for the jellies.

5:24PM PDT on Sep 25, 2013

Many of these jellyfish are really beautiful - but it seems they are also a threat. I hate the thought that they be killed to control their (obviously huge) numbers, so perhaps a limited quota could be caught for food; which would avoid the need for a mass slaughter, and also provide poor people with a readily available food source.

5:27AM PDT on Sep 25, 2013

I'm surprised nothing!! The humans do all wrong, and at the end we kill ourselfs by stupidy.
The oceans are almost empty, and I agree with Marilyn M. with the overfishing and killing whales and other creatures, and then the humans wonder why.
Mass killing around the world.
Someone intelligent says, the nature dies first and then the humans. Perfectly right what he or she says.

4:59AM PDT on Sep 25, 2013

At one time (many millions of years ago) jellyfish were the dominant lifeform on Earth. I guess it's true; the more things change, the more they remain the same!

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Kristina Chew Kristina Chew teaches ancient Greek, Latin and Classics at Saint Peter's University in New Jersey.... more
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