Skip to main content

Jellyfish love the oceans we pollute

By Lisa-ann Gershwin
November 15, 2013 -- Updated 1927 GMT (0327 HKT)
A 5-foot giant jellyfish recently washed up on a beach in Tasmania, an island off the southeast coast of Australia. Scientists are working to classify the new species. Click through the gallery to see more photos of jellyfish around the world. A 5-foot giant jellyfish recently washed up on a beach in Tasmania, an island off the southeast coast of Australia. Scientists are working to classify the new species. Click through the gallery to see more photos of jellyfish around the world.
HIDE CAPTION
A new species
West Coast sea nettle
Not their natural color
"Turn off the lights, and we'll glow."
"Am I getting hazard pay for this?"
Lion's mane
Papuan jellyfish
Pacific sea nettle
Summer invadors
Painful but pretty
Jellyfish and tourism
The Irukandji
<<
<
1
2
3
4
5
6
7
8
9
10
11
12
>
>>
STORY HIGHLIGHTS
  • Lisa-ann Gershwin: Jellyfish taking over vulnerable seas, displacing other creatures
  • She says jellyfish can kill off fish-sustaining krill that's harvested for omega-3 supplements
  • Gershwin: Jellyfish thrive as oceans get warmer; they eat the eggs and larvae of fish
  • Gershwin: We need to make industry stop polluting water and prevent global warming

Editor's note: Lisa-ann Gershwin has been researching jellyfish more than 20 years and discovered more than 180 new species, including 16 that are potentially lethal. In 1998, she was awarded a Fulbright Fellowship to study jellyfish blooms and fossil jellyfish in Australia. Lisa is the director of the Australian Marine Stinger Advisory Services, and the author of "Stung! On Jellyfish Blooms and the Future of the Ocean" (May 2013, University of Chicago Press). She is based in Hobart, Tasmania.

(CNN) -- "Ouch!" is what most of us think when we think of jellyfish. They sting. They're slimy and they have no brains. So who would've predicted that the lowly jellyfish could emerge from the shadows as a destroyer of fisheries and ecosystems and even as a threat to penguins and whales.

Far down in Antarctica -- the last pristine wilderness, some might say -- the balance is shifting from krill to jellyfish. In this harsh land, just about everything bigger than a krill eats krill: whales, seabirds, fish and penguins.

Lisa-ann Gershwin
Lisa-ann Gershwin

But krill are disappearing, thanks to us and the jellyfish. We fish out vast amounts of krill for our omega-3 supplements; the jellyfish eat vast quantities of plankton, leaving little for the krill to eat.

All over the world, from the Bering Sea to the Sea of Japan, from the Mediterranean to the Gulf of Mexico, from China to the Chesapeake, from the Black Sea to the Baltic to the Benguela off Namibia, any place oceans are in trouble, jellyfish are taking over. Jellyfish do well in warmer waters. Our carbon dioxide emissions are both warming the water and causing it to become corrosive. Warmer water -- even a fraction of a degree -- holds less oxygen than cooler water and shifts the balance of who survives and who perishes.

News: Jellyfish taking over ocean, experts warn

A strange type of jellyfish-like creature called a salp is particularly taking advantage. Salps are surely one of the world's most bizarre critters. They can grow 10% of their body length per hour and go through two generations in a day. They are more closely related to humans than to most other types of jellyfish, though they certainly don't look like it. Their bodies look like clear, gelatinous barrels. Salps don't sting, but they do their damage in their staggering numbers. Ask the operators of Diablo Canyon nuclear power plant on the coast of central California.

Jellyfish block grills at a power station in Hadera, Israel, in 2011. Salps shut down a California nuclear plant temporarily in 2012.
Jellyfish block grills at a power station in Hadera, Israel, in 2011. Salps shut down a California nuclear plant temporarily in 2012.

In April 2012, Diablo was plunged into emergency shutdown because of salps clogging up the seawater intake pipes for the cooling system. This might seem freakish, but jellyfish have caused many dozens of such shutdowns at nuclear power plants, coal-fired power plants, desalination plants -- pretty much any type of industry that draws seawater. Even seawater-cooled data centers such as Google's Finnish facility are at risk.

Different types of jellyfish have caused mass fish kills at salmon farms all over the world. Ireland, Scotland, Chile, Australia, New Zealand... you name it. If salmon are being farmed, you can bet there are terrible jellyfish problems.

Jellyfish have also taken over Lurefjorden, one of Norway's beautiful fjords and previously one of its best fishing spots. There is nary a fish to be found. Recently, two more fjords have also become colonized by jellyfish as their fisheries have declined.

The stings and emergency shutdowns are bad -- and let's face it, that whole slimy thing is a bit off-putting -- but the real problem with jellyfish is in their predator-prey dynamic with fish. On the face of it, fish are obviously the superior predator: They are smarter, faster and often bigger. Think of sharks and stingrays and largemouth bass: It's hard to imagine that jellyfish could possibly hold their own against these fighters. But jellyfish are sneaky. They eat the eggs and larvae of fish, and the plankton that the larvae would eat. And through this double whammy of predation and competition, they can cripple an ecosystem at the ankles.

World's jellyfish population booming

But jellyfish do other harm, which is only just beginning to be appreciated. They flip the food chain upside down. Normally as you go up the food chain, the energy value increases. For example, shrimp pack more energy than their plankton prey, but big fish that eat shrimp are better still. Hower, jellyfish, a very low-energy choice compared with shrimp or fish, are sequestering the higher energy of these species into their own low-energy bodies. They are, in essence, spinning gold into straw, or turning wine into water.

In a healthy ecosystem, fish are superior competitors and predators over jellyfish. But the things we humans do -- we fish, we pollute, we dam, we build, we translocate -- are making life harder for fish and better for jellyfish. And so, as we look around the world, we see that many of the most heavily disturbed ecosystems have "flipped" to being dominated by jellyfish instead of fish. Moon jellies and comb jellies in the Inland Sea of Japan. Sea nettles in the Chesapeake and the Benguela current off Namibia. Comb jellies in the seas of Europe. Santa's hat jellies in the fjords of Norway. Refrigerator-sized jellies growing in the seas of China and drifting into Japanese and Korean waters.

And once in control, they don't seem to be letting go.

So, we find ourselves in the unimaginable position of being in competition with jellyfish -- and make no mistake, they have the home-court advantage.

So, what can we do? What should we do? That's the problem. The ocean is our life support system -- it's where we get our food, our oxygen, many of our industries and often our inspiration. But we don't have a solution for the damages we are causing. We need to buy time, so solutions can be innovated.

We need to invest in research to slow down the damage as well as to cope with our rapidly changing world. And we need to begin serious dialogue about what we value and what we are willing to do to preserve it.

We could start by legislating a clean-to-intake standard in which any air or water discharged by industry must be at least as clean as it was going in, or the industry is not permitted to operate. Sure, there would be great gnashing of teeth, but quite quickly, polluting industries would have to innovate ways to be cleaner to stay economically viable. This is just one example, but we must think of many more. And we must do something.

I read somewhere recently that we in all likelihood will go down in history as the generation that could have saved the ocean but chose not to. It made me cry, because I fear it is true.

Follow us @CNNOpinion on Twitter.

Join us at Facebook/CNNOpinion.

The opinions expressed in this commentary are solely those of Lisa-ann Gershwin.

ADVERTISEMENT
Part of complete coverage on
July 30, 2014 -- Updated 1941 GMT (0341 HKT)
Stuart Gitlow says pot is addictive and those who smoke it can experience long-term psychiatric disease.
July 30, 2014 -- Updated 1645 GMT (0045 HKT)
Gabby Giffords and Katie Ray-Jones say "Between 2001 and 2012, more women were shot to death by an intimate partner in our country than the total number of American troops killed in the Iraq and Afghanistan wars combined."
July 29, 2014 -- Updated 2357 GMT (0757 HKT)
Alan Elsner says Secretary Kerry's early cease-fire draft was leaked and presented as a final document, which served the interests of hard-liners on both sides who don't want the Gaza war to stop.
July 30, 2014 -- Updated 1158 GMT (1958 HKT)
Vijay Das says Medicare is a success story that could provide health care for everybody, not just seniors
July 30, 2014 -- Updated 1818 GMT (0218 HKT)
Rick Francona says Israel seems determined to render Hamas militarily ineffective.
July 30, 2014 -- Updated 1743 GMT (0143 HKT)
S.E. Cupp says the entrepreneur and Dallas Mavericks owner thinks for himself and refuses to be confined to an ideological box.
July 30, 2014 -- Updated 1311 GMT (2111 HKT)
A Christian group's anger over the trailer for "Black Jesus," an upcoming TV show, seems out of place, Jay Parini says
July 30, 2014 -- Updated 2028 GMT (0428 HKT)
LZ Granderson says the cyber-standing ovation given to Robyn Lawley, an Australian plus-size model who posted unretouched photos, shows how crazy Americans' notions of beauty have become
July 30, 2014 -- Updated 1939 GMT (0339 HKT)
Carol Dweck and Rachel Simmons: Girls tend to have a "fixed mindset" but they should have a "growth mindset."
July 28, 2014 -- Updated 1156 GMT (1956 HKT)
A crisis like the Gaza conflict or the surge of immigrants can be an opportunity for a lame duck president, writes Julian Zelizer
July 26, 2014 -- Updated 1822 GMT (0222 HKT)
Carol Costello says the league's light punishment sent the message that it didn't consider domestic violence a serious offense
July 28, 2014 -- Updated 1251 GMT (2051 HKT)
Danny Cevallos says saggy pants aren't the kind of fashion statement protected by the First Amendment.
July 28, 2014 -- Updated 1852 GMT (0252 HKT)
Margaret Hoover says some GOP legislators support a state's right to allow same-sex marriage and the right of churches, synagogues and mosques not to perform the sacrament
July 28, 2014 -- Updated 1831 GMT (0231 HKT)
Megan McCracken and Jennifer Moreno say it's unacceptable for states to experiment with new execution procedures without full disclosure
July 30, 2014 -- Updated 1744 GMT (0144 HKT)
Priya Satia says today's drones for bombardment and surveillance have their roots in the deadly history of Western aerial control of the Middle East that began in World War One
July 28, 2014 -- Updated 1635 GMT (0035 HKT)
Jeff Yang says it's great to see the comics make an effort at diversifying the halls of justice
July 26, 2014 -- Updated 1555 GMT (2355 HKT)
Rick Francona says the reported artillery firing from Russian territory is a sign Vladimir Putin has escalated the Ukraine battle
July 27, 2014 -- Updated 1822 GMT (0222 HKT)
Paul Callan says the fact that appeals delay the death penalty doesn't make it an unconstitutional punishment, as one judge ruled
July 24, 2014 -- Updated 2225 GMT (0625 HKT)
Pilot Robert Mark says it's been tough for the airline industry after the plane crashes in Ukraine and Taiwan.
July 25, 2014 -- Updated 1510 GMT (2310 HKT)
Jennifer DeVoe laments efforts to end subsidies that allow working Americans to finally afford health insurance.
July 26, 2014 -- Updated 1533 GMT (2333 HKT)
Ruti Teitel says assigning a costly and humiliating "collective guilt" to Germany after WWI would end up teaching the global community hard lessons about who to blame for war crimes
July 25, 2014 -- Updated 1245 GMT (2045 HKT)
John Sutter responds to criticism of his column on the ethics of eating dog.
July 25, 2014 -- Updated 1302 GMT (2102 HKT)
Frida Ghitis says it's tempting to ignore North Korea's antics as bluster but the cruel regime is dangerous.
July 25, 2014 -- Updated 1850 GMT (0250 HKT)
To the question "Is Putin evil?" Alexander Motyl says he is evil enough for condemnation by people of good will.
July 24, 2014 -- Updated 1803 GMT (0203 HKT)
Laurie Garrett: Poor governance, ignorance, hysteria worsen the Ebola epidemic in Sierra Leone, Guinea, Liberia.
July 24, 2014 -- Updated 1349 GMT (2149 HKT)
Patrick Cronin and Kelley Sayler say the world is seeing nonstate groups such as Ukraine's rebels wielding more power to do harm than ever before
July 23, 2014 -- Updated 2205 GMT (0605 HKT)
Ukraine ambassador Olexander Motsyk places blame for the MH17 tragedy squarely at the door of Russia
July 24, 2014 -- Updated 1142 GMT (1942 HKT)
Mark Kramer says Russia and its proxies have a history of shooting down civilian aircraft, often with few repercussions
July 24, 2014 -- Updated 1853 GMT (0253 HKT)
Les Abend says, with rockets flying over Tel Aviv and missiles shooting down MH17 over Ukraine, a commercial pilot's pre-flight checklist just got much more complicated
July 24, 2014 -- Updated 1317 GMT (2117 HKT)
Mark Kramer says Russia and its proxies have a history of shooting down civilian aircraft, often with few repercussions
July 24, 2014 -- Updated 1637 GMT (0037 HKT)
Gerard Jacobs says grieving families and nations need the comfort of traditional rituals to honor the remains of loved ones, particularly in a mass disaster
July 24, 2014 -- Updated 1413 GMT (2213 HKT)
The idea is difficult to stomach, but John Sutter writes that eating dog is morally equivalent to eating pig, another intelligent animal. If Americans oppose it, they should question their own eating habits as well.
July 23, 2014 -- Updated 1630 GMT (0030 HKT)
Bill van Esveld says under the laws of war, civilians who do not join in the fight are always to be protected. An International Criminal Court could rule on whether Israeli airstrikes and Hamas rocketing are war crimes.
July 30, 2014 -- Updated 1209 GMT (2009 HKT)
Gordon Brown says the kidnapped Nigerian girls have been in captivity for 100 days, but the world has not forgotten them.
ADVERTISEMENT