As I write these words, jellyfish are behaving badly all over the place. I don’t mean in the philosophical sense… I mean they are literally stinging people and blocking fishermen’s nets and causing problems by the squillions. Now.

Just a few of the headlines in the past few days:

– More than 200 people were treated for jellyfish stings this past weekend alone in Volusia County, Florida [1], while 60 tourists were stung this past weekend in Java, Indonesia [2].
– Jellyfish are worse than ever for fishermen in the UK [3], while at least 20 people were stung in China, with 8 requiring hospital care [4], and the Irukandjis have returned to Grand Cayman [5] – if you don’t know what “Irukandji” is, go make yourself a large cappuccino, get comfortable in your chair, and google it (be prepared to be amazed).

There is a fine line between normal jellyfish blooms and jellyfish gone wild. And sometimes it’s hard to tell the difference. In Stung! On Jellyfish Blooms and the Future of the Ocean I open and close with the story of fossilized jellyfish blooms in the Cambrian, hundreds of millions of years ago, stranded in time in what is now central Wisconsin. While one such fossil bed would be enough to marvel at, seven consecutive bedding planes of fossilized jellyfish blooms tells us with certainty that this is just what jellyfish do.

So what’s different now? Why is it all of a sudden such a problem? In Part 2 of The Rise of Slime, we looked at some of the impacts that we humans are causing to the ocean. It’s a lot, actually. Overfishing. Habitat destruction. Turbidity (cloudiness). Warming water. Corrosive water. Too much fertilizer. Plastic pollution. Radioactive waste. DDTs. PCBs. Heavy metals. Dioxins. Nerve toxins. Chemotherapy drugs. Gender benders…

Something’s got to give.

So as fish falter and ecosystems reshuffle, the opportunists seize the moment. But how? How does the lowly brainless jellyfish, with no bones, no blood, no heart or soul… how does the jellyfish go from being the underdog to the top dog? It’s simple, and again, it’s just what jellyfish do.

Jellyfish eat the eggs and larvae of fish, as well as the plankton that the larvae would eat. They can’t out-compete in a healthy ecosystem, but this double whammy of predation and competition means that when the balance is shifted, even just a little, then jellyfish can ratchet their way to domination. And indeed they do. Jellyfish don’t dominate every bay and harbor, of course, but they do dominate many. And as we continue to shift the balance in ecosystems, jellyfish may continue to flourish.


One of the jellyfish fossils from the Wisconsin quarry, showing evidence of typical stranded behavior. As the jellyfish struggles, its pulsations essentially excavate a hole around its margin and build up sediment near the center, even filling the mouth and stomach cavities, as is seen here.

But it’s more than that. I didn’t have the idea fully formed at the time the book went to press, but I am now convinced that we are in the uncomfortable position of being in competition with jellyfish for food… but they have the home-court advantage. Jellyfish are not only simplifying ecosystems… they are simplifying the food chain… our food chain.

Normally, each time something eats something else, the predator retains 10% of the calories of its prey. So, in general, the higher you go on the food chain, the “better quality” energy you get. Cow meat and pig meat give you more bang for the buck, ounce for ounce, than the grass or slop that they ate. So, while eating wheatgrass and spirulina are very fashionable, in fact, our bodies would rather have greasy spare ribs or a thickly marbled steak.


While the thought of jellyfish fossilizing might seem strange, and the thought of jellyfish in Wisconsin might seem even stranger, in fact, not one but seven of the most splendid oddities of natural history are to be found in the stranded jellyfish fossils in what is now central Wisconsin. This photo looks out over the quarry, with each lump and hole marking a jellyfish that met its untimely demise hundreds of millions of years ago during the Cambrian.

But jellyfish turn that all around backwards. Jellyfish eat the eggs and larvae of fish (high quality food) and convert that food energy into their own body mass (low quality food). They are one of the few organisms that does this as a normal means of living. This would be like grass eating us, or like deer eating wolves.

Since neither we nor other animals like to eat most species of jellyfish, this means that the food energy is not only lost, but it actually powers more jellyfish to have more babies. Bad news.

How we deal with this is up to us, and we explore this in the next installment.

[1] http://www.wptv.com/dpp/news/state/more-than-200-people-treated-for-jellyfish-stings-along-the-volusia-county-coastline

[2] http://asia.etbnews.com/148220/jellyfish-sting-swimming-tourists-in-java/

[3] http://www.thecourier.co.uk/news/local/angus-the-mearns/angus-fishery-feels-sting-of-explosion-in-jellyfish-numbers-1.119482

[4] http://english.peopledaily.com.cn/90882/8359130.html

[5] http://www.caymannewsservice.com/science-and-nature/2013/08/08/box-jelly-fish-bring-%E2%80%98joy-and-pain%E2%80%99

Check out the fourth installment of Lisa-ann Gershwin’s series Rise of Slime next week!

Lisa-ann Gershwin is the Director of the Australian Marine Stinger Advisory Services, and is now with CSIRO Marine and Atmospheric Research in Australia. Her most recent book is Stung! On Jellyfish Blooms and the Future of the Ocean published by the University of Chicago Press.

The Paleontological Research Institution, Ithaca, New York, is pleased to sponsor Paleontology content for This View of Life. Founded in 1932, PRI has outstanding programs in research, collections, and publications, and is a national leader in development of informal Earth science education resources for educators and the general public.

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Published On: August 26, 2013

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