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article imageOp-Ed: The jellyfish invasion spreads deadly Irukandji around the world

By Paul Wallis     Sep 9, 2013 in Environment
Sydney - The Australian Irukandji jellyfish is the most venomous creature on Earth. Its appearance in places as far apart as Cape Town and Florida isn’t good news . Unlike other jellyfish, this species is a real environmental hazard.
ABC Australia quotes Professor Tim Flannery from the Australian Climate Commission:
"The main predators of jellyfish are gone and the main competitors of jellyfish are gone," he said.
"So when there's a big jellyfish bloom, those jellyfish can really take over the eco-system and they do that by killing and consuming any fish eggs in the water and any fish larvae and just building up in enormous numbers."
The threat is very real. Marine harvesting also accounts for a massive proportion of the world’s food resources. Some years ago, I reported on a jellyfish attack on a Northern Irish aquaculture facility which wiped out its salmon stock. The jellyfish were a Mediterranean species, not usually found in the North Sea.
From that report:
What happens if your salmon farm gets attacked by a 35 foot deep, 10 square mile horde of jellyfish? You’re short a salmon farm, and $2 million worth of fish. The massive plague wiped out 100,000 salmon, and the company which was farming them.
It was an economic catastrophe. These jellyfish, whatever they were, also weren’t in the same league as the Irukandji.
This is a brief description of the Irukandji (their bigger relatives are known as “box jellyfish”) from
Most jellyfish are little more than gelatinous bags containing digestive organs and gonads, drifting at the whim of the current. But box jellyfish are different. They are active hunters of medium-sized fish and crustaceans, and can move at up to twenty-one feet per minute. They are also the only jellyfish with eyes that are quite sophisticated, containing retinas, corneas, and lenses. And they have brains, which are capable of learning, memory, and guiding complex behaviors.
The Irukandjis are diminutive relatives of the box jellies.
They’re also capable of hitting actual plague proportions. In Northern Australia, jellyfish warnings are taken more seriously than shark warnings. The sting is excruciating, and can be lethal. Since 1884, 76 people are known to have died from the stings, and many cases may have been misdiagnosed or misreported.
The sting of the Irukandji also causes intense suffering and pain. Symptoms include: explains:
It’s now known that the brush of a single tentacle is enough to induce “Irukandji syndrome.” It sets in twenty to thirty minutes after a sting so minor it leaves no mark, and is often not even felt. Pain is initially focused in the lower back. Soon the entire lumbar region is gripped by debilitating cramps and pounding pain—as if someone is taking a baseball bat to your kidneys. Then comes the nausea and vomiting, which continues every minute or so for around twelve hours. Shooting spasms grip the arms and legs, blood pressure escalates, breathing becomes difficult, and the skin begins to creep, as if worms are burrowing through it. Victims are often gripped with a sense of “impending doom” and in their despair beg their doctors to put them out of their misery.
The real problem with Irukandkji
Suffice to say that an exploding population of predatory, highly invasive Irukandji worldwide is likely to turn into a real catastrophe for coastal populations, tourism, and the fishing industry. That’s particularly the case in non-Australian waters, where they have no natural predators.
It’s also not good news for shipping. Even the USS Ronald Reagan, a nuclear powered aircraft carrier, had to leave port when its cooling system was fouled by Irukandji in 2006. That date also happens to be roughly within the timespan of the first reports of major jellyfish plagues. This information also fits in well with well-known studies of invasive species transported by ballast water.
Jellyfish are one of the oldest forms of life on Earth. They’ve been around for 500+ million years, and have survived all the major extinctions. They don’t mind low oxygen and other environmental conditions which would be lethal to more advanced animals. The sorry state of the world’s oceans has in fact been a blessing for them, creating lots of no go zones for their predators. Plastic bags are nice places for them to breed more jellyfish, safe from harm.
What is not commonly known about jellyfish populations is their breeding capacity. They are quite capable of producing billions of individuals, able to literally annihilate prey species. They make drift nets look positively benevolent.
If you haven’t seen a real jellyfish plague, it’s a bit hard to grasp the numbers involved. As a kid staying in Queensland, I remember seeing the results of a storm:
The water was full of jellyfish, in fact it was almost all jellyfish. Even the waves were waves of jellyfish. The beach was so heavily infested with washed up jellyfish there was nowhere to walk to even get near the water. There was about 10-20 yards of solid jellyfish.
This happened almost overnight. You’d see the odd big jellyfish, normally. Then the entire beach and the ocean was just one big mass of jelly. Nobody could have suspected the sheer scale of the population numbers.
The point of this tale is that this happened before the mega-populations of jellyfish we’re seeing now, which dwarf all previous models. In theory, one huge Irukandji bloom could obliterate whole fishing zones, and destroy any possibility of recovery by simply reducing fish populations to below the threshold of survival. Even these reduced populations would be subject to future Irukandji plagues.
This is not a drill
The big jellyfish problems have been reported before. In Japan, China, and elsewhere, monster jellyfish are well known problems. This is different. The Irukandji and their relatives are real monsters. Action is required, now. The plagues can strike in a day.
It may be possible to:
Use the ballast process against them, by selectively taking them into ballast during plague events. Adding a jellyfish killer to ballast water could cut down populations of Irukandji. It’s a simple fix for a very complex problem.
Ensure that local fishing industries are well aware of the risks, and to report Irukandji if they find them. (There’s also an OHS issue for the industry. You could wind up with dead crew if they appear in a catch and are handled.)
Map their presence in a coordinated global effort. They probably have gone worldwide and are certainly present in the Atlantic. It’s a matter of recognition.
It is at least theoretically possible to stop them and simultaneously reduce their ability to spread. The previous governmental apathy about jellyfish is now a serious liability, though. If seafood prices go through the roof and catches dwindle, the world has a serious food problem.
That can happen very quickly with these huge populations of jellyfish. Trouble is, if nothing is done, the outcomes are inevitable. There’s no good side to this problem, and it’s becoming critical.
This opinion article was written by an independent writer. The opinions and views expressed herein are those of the author and are not necessarily intended to reflect those of
More about Irukandji, Invasive species, marine ecology, Prof Tim Flannery, Australian Climate Commission
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