Jellyfish: A Warning of Times to Come

Jellyfish normally become plentiful around August, off the coasts of Korea, but now the world-wide plague of jellyfish have become more so a sign of over-fishing, pollution and global warming than of a fluke. Per the National Science Foundation, in one study notes that:

“Human-caused stresses, including global warming and overfishing, are encouraging jellyfish surpluses in many tourist destinations and productive fisheries,”

The Chosun Ilbo reports that, in August, “southern and western beaches may appear to be nearly half water and half jellyfish.” Recent jellyfish blooms have wrecked much damage on fishermen, who can not ply their trade due to these stinging menace that ruin their nets and their catch.
According to an article from 2004, in the Korea Times, filefish — a natural predator of jellyfish — have been over-fished around Korea to the point where jellyfish have flourished due to not just increasing temperatures but due to the absence of natural predators. As per the timesonline:

The problem has become so serious that fishery officials from Japan, China and South Korea are to meet this month for a “jellyfish summit” to discuss strategies for dealing with the invasion.

According to Jaunted, seventy swimmers have already been treated on the beaches of Pusan for jellyfish stings and even in a recent New York Triathlon, one Argentine athlete was killed after being stung by a lion’s mane jellyfish. (see the “jaunted” link for more articles). A New York Times article notes that jellyfish will become more plentiful:

The warmer seas and drier climate caused by global warming work to the jellyfish’s advantage, since nearly all jellyfish breed better and faster in warmer waters, according to Dr. Jennifer Purcell, a jellyfish expert at the Shannon Point Marine Center of Western Washington University.

Global warming has also reduced rainfall in temperate zones, researchers say, allowing the jellyfish to better approach the beaches. Rain runoff from land would normally slightly decrease the salinity of coastal waters, “creating a natural barrier that keeps the jellies from the coast,” Dr. Gili said.

Then there is pollution, which reduces oxygen levels and visibility in coastal waters. While other fish die in or avoid waters with low oxygen levels, many jellyfish can thrive in them. And while most fish have to see to catch their food, jellyfish, which filter food passively from the water, can dine in total darkness, according to Dr. Purcell’s research.

  • Wedge

    Is there nothing that global warming can’t do?

  • user-81

    Blaming global warming is premature. A more likely explanation is this: Free trade and neo-liberal economics has meant greater affluence. Greater affluence means more people have time and money to enjoy leisurely activities like travel. More travel means more people hitting the beaches. More people hitting the beaches naturally means more people getting stung by jellyfish. Connecting these rising attacks to a higher jellyfish population is academic misconduct.

  • user-81

    Also, since Koreans eat jellyfish this could be signs of an economic boon. Why look at the glass as half empty, Elgin?

  • Bad Monkey

    Re #2:

    “A more likely explanation is this…”

    That is only a more likely explanation to someone who refuses to admit the scientific evidence of 1) worldwide expansion of jellyfish populations and ranges, and 2) a whole host of dramatic and alarming changes in marine environments worldwide. Before cavalierly slinging around epithets like ‘academic misconduct’, maybe you should at least read the New York Times article? Here’s one fragment:

    “From Spain to New York, to Australia, Japan and Hawaii, jellyfish are becoming more numerous and more widespread, and they are showing up in places where they have rarely been seen before, scientists say. ”

    How much of this is ascribable to global warming? Very hard to say, although few scientists who study the oceans doubt that it is one factor involved. Another quote:

    “The explosion of jellyfish populations, scientists say, reflects a combination of severe overfishing of natural predators, like tuna, sharks and swordfish; rising sea temperatures caused in part by global warming; and pollution that has depleted oxygen levels in coastal shallows.”

    In such complex systems it is very difficult of course to measure or even estimate exactly how much global warming contributes to this particular problem. What is clear is that, in marine environments subject to all kinds of stresses, warming just serves to exacerbate the problems.

  • user-81

    @ Bad Monkey re #4:
    Oxfam’s razor tells me that if I have to choose between the whole world getting one degree warmer and falling apart OR that biologists in academia are a bunch of bleeding heart neofascists, I pick Door #2.

  • obamafan

    Thanks to Wedge and user-81 for filling their roles of knee-jerk enviro-skeptics nicely! Job well done, chaps. The checks/cheques are in the mail.

    What is interesting about the enviro-skeptics is they are very good at “negative jurisprudence” (i.e. bringing a theory down) but woeful at “positive jurisprudence” (i.e. puting forward a theory explaining what is going on in the world. Take user-81’s intriguing theory at #2. This seems to assume either that local people have not been going to beaches (explaining the increase in numbers because of visitors from outside the area) or that local people do not suffer from jellyfish stings — only visitors do.

  • R. Elgin

    That is “Occam’s razor” and *you* should not play with very old, sharp objects that you do not know how to use.

    The world-wide occurrence of governments sponsoring over-fishing of the seas is well documented and discussed (internet search). If the predators of jellyfish are being over fished or killed off through the machinations of mankind, and conditions exist that favor this jelly cockroach, then this sort of thing could likely occur.

  • soondae

    ‘bleeding heart neofascists’
    Pardon my ignorance, but what exactly does this mean?

  • user-81

    @ R. Elgin re #7:
    “That is “Occam’s razor” and *you* should not play with very old, sharp objects that you do not know how to use.”

    That was a first-class retort. I applaud your response. It made me laugh. As a reward I’ll send you two sarcasm detectors. You can give one to obamafan.

  • roboseyo

    I thought it was the CIA seeding the oceans with jellyfish. They got bored after planning 9/11.

    (just testing out your new sarcasm detectors)

  • WangKon936

    So… Jellyfish are the proverbial global warming canary in the mine shaft?

  • Railwaycharm

    The reason we have too many jellyfish in the ocean girls is because there are less predators to eat them. Convince the Japanese to stop eating sashimi and you won’t get your dick stung this summer in the ocean. Fuck a bunch of global warming.

  • Brendon Carr (Korea Law Blog)

    It’s pretty clear the jellyfish are moving into the ecological niche formerly filled up by tasty, delicious fishies. (Don’t blame me, though — I’m from St. Louis, and Fear the Seafood™.)

    But it ain’t from global warming, even though the ecological niche is made vacant by human activity.

    I’m so sick of hearing global warming this, global warming that. Global warming, if it is indeed occurring, is not caused by human activity. Get over yourselves. We’re going through a period of reduced sunspot activity, which means more energy is being radiated by our friend Mr. Sun. Temperatures have been observed increasing on several planets and moons of gas-giant planets. Pretty dastardly of George Bush to raise the temperature on Mars!

    No, instead the rest of you fuckers are simply eating too much fish. That’s relatively easy to fix.

    If we reduce fishing quotas and allow fish stocks to recover, the jellyfish populations will be reduced pretty quickly. It only takes a few years for things to return to normal. The problem is that fishing-quota enforcement depends on governments (that word again) and rule of law.

    Watch Deadliest Catch and note that the crabbing “season” is tightly regulated — Alaskan fishermen know that if they catch crabs outside the season, catch too many crabs, or even get back to port too slowly with a hold of in-quota crabs, and they face serious legal sanctions.

    Koreans really like seafood, making them one of the world’s largest fishing nations. And they don’t much like laws — either joining international treaties (like the Commission for the Conservation of Southern Bluefish Tuna, which Koreans love to eat), or enforcing their own laws consistently. Korean fishing fleets are drawn nearly inexorably to African coastal waters, where weak governments either do not enforce laws or can be bought off when they do.

    Addressing the jellyfish issue means getting Koreans to buy off on something where they sacrifice, and we benefit. Good luck with that.

  • R. Elgin

    It is not just the Koreans that over-fish but Spain, France, Italy, Iceland, etcetera and their governments seem to be content to let it go until commercial fishing will be no longer sustainable. Then we can discover how this affects a global food shortage as well.

  • Railwaycharm

    #14 Chilean sea bass will soon be gone as well.

  • hoju_saram

    No suprises here – a post about the environment and the usual conservative suspects are jostling to naysay it. I never have worked out what the environment has to do with politics, but there you have it. Richardson will be along soon to claim global warming is a “cult”.

    Global warming is real – the scientific evidence is overwhelming. So are rising sea-temperatures. Whether these are man-made effects or not is still open to debate.

    Re the jellyfish, I tend to agree with the warm water theory. From personal experience, having been stung hundreds of times while surfing and never once in winter, I know that jellyfish increase when the water is warmer. Logically it follows that if the average water temp increases slightly, so, probably, will the jellyfish populations.

    The overfishing idea is obviously popular with the Wedges and Brendons of the world because it doesn’t require global warming. It may play a part. The theory is that as fish numbers decrease, fish-food (and jellyfish food) increases, thus bouying the jellyfish populations. Problem is, jellyfish populations are booming where fish stocks are relatively stable, like the Gold Coast, my home town.

  • Above Criticism

    “I never have worked out what the environment has to do with politics, but there you have it.”

    The connection is that many conservatives are convinced that global warming is nothing more than a dangerous UN/European/”socialist” plot to undermine global capitalism and stifle the American way of life (see also the death penalty, gun laws, religion).

  • Kujo

    global warming? rush limpballs tells me there is no such thing, therefore, the basic foundations of this story are wrong

    how can you spread these liberal lies?

    you need to get yourself saved, mr koehler- saved!

  • NES

    @5 user-81

    Me too.

  • abcdefg

    We’re going through a period of reduced sunspot activity, which means more energy is being radiated by our friend Mr. Sun. Temperatures have been observed increasing on several planets and moons of gas-giant planets. Pretty dastardly of George Bush to raise the temperature on Mars!

    Your science is incorrect. A period of low sunspot activity would correspond to lower global temperatures (ie, sunspots give off lots of radiation!).

    Anyway, some scientists believe the present solar cycle will have a minimum of sunspots — and, consquently, urge the world to brace for a mini ice age.

  • Wedge

    #5: Heh. Oxfam’s Razor.

    The problem with global warming evangelistas is a really lousy PR approach. When you have people knowingly exaggerate a problem in order to get more of the world’s attention, and a lot of “scientists” have admitted doing this, people will see through it and stop paying attention. There could be a kernel of truth but they’ve already lost their audience.

    Farces like “An Inconvenient Truth” and “Day After Tomorrow,” not to mention Di Craprio’s load of codswallop (I can’t be bothered to look the name of it up), only preach to the faithful. The average enviro-infidel calls bullshit on the propaganda.

    Some of us geezers remember 1975 and the doom-du-jour: a rapidly approaching ice age. Guess what? It made the cover of Newsweek and Time back then as well. Fool me once…

  • NES
  • NES


    Yeah, we’ve actually entered a cooling cycle for the past ten or so years, which is why the government funding whores have gone from calling it “global warming” to “global climate change.”

  • NES

    Don’t worry. The UN will solve the global warming problem, just like all of the other problems they’ve solved:

    Warming to debate the art of hypocrisy,21985,22726074-25717,00.html

    ‘Sickening’ U.N. Elitists Gorge on Caviar as Africans Starve

    UN Climate Change Bureaucrats Jet to Bali

    In need of jet valet parking

  • NES

    …and don’t miss Al Gore’s new movie: SUPERNOVA

  • Jerry

    There are many reasons for changes in the “dominate” fish specie in a certain area, some still not fully understood by science. You can have one fish specie totally dominating an area of the ocean for 10-20 years, then another specie takes over for few decades. In the beginning of the 20th century, California’s coast was filled with sardines. Then by 1950s the sardine industry collapsed. Scientists now believe that it was a cyclical event based on changes in ocean temperature, not over-fishing by man.

    Mankind’s fishing activities is just one of many factors that impacts the local fish population. But it does have a heavy impact on the fish’s size. If you take too many fish, then the overall size of the adult fish caught will decrease.

    The US-Canada agreement on Pacific Halibut take is a fairly successful attempt at protecting the Halibut fishery in the Pacific NW. To this day you can still catch very large sized Halibut from Vancouver to Alaska. Same with the Alaskan crab fishery. Elsewhere, we’ve not been very successful. California is supposed to be a very environmentally progressive state, but coastal fishery protection has been pretty lacking. Compare the average size of mackerel and bonito from 1970s to 2000s caught from CA piers.

  • WangKon936


    You are such a “know it all…”

    I know you spend 15 hours a day on wikipedia!… 😉

  • arthjmI

    Have any of you tried jellyfish in Korea? Sadly, I never have, but I’m really curious about it now. If the popularity of it does catch on, I’m sure many countries would be more than eager to sell them for discount prices

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