First off, the common name is a misnomer; jellyfish aren’t actually fish, and aren’t even vertebrates (some folks call them “jellies” to clear up this misconception). A backbone isn’t the only body part they lack—they’re also missing specialized respiratory, digestive, circulatory, and central nervous systems. Their “brains” are merely nerve nets. Most don’t even have true eyes—they might have, at best, sensory organs which can detect light. Also, most don’t even truly swim. They just drift along in the current. Despite this, jellyfish are carnivorous, as they sweep up other small organisms that become tangled in their tentacles and pass close by their bodies. Like flatworms, they have a rather disturbing attribute; one hole serves as both a mouth and an anus. Jellyfish structurally consist of a main body, or “bell,” with tentacles extending from this. Their bodies are typically roundish in shape, or squarish. All of these primitive characteristics aren’t surprising, given that they’re so ancient a species. Really ancient. Like 500-700 million years old. They are, actually, the oldest multi-organ animal. So they’re primitive and simple, to the extreme, but it’s sure worked well for them.
There is a fair bit of variety within the species. Some types reproduce asexually, others sexually. Most are marine, but a few can live in fresh water. Most dramatically, some are less than an inch long, while others, counting their extended tentacles, can be over a hundred feet long. The heaviest one is the Nomura’s Jellyfish, which body ranges up to a two meter (6.6 feet) diameter, and weighs up to 200 kilograms, or 440 pounds.
But when we discuss jellyfish, there’s the animal’s most distinctive trait—their sting. When I was a child swimming off the coast of
Ocean City, NJ, I encountered
this several times. As I recall, late
summer was the worst time, when they would be plentiful. These jellyfish, which were about 6 inches to
a foot in diameter, fortunately had relatively minor stings. Slight pain and some skin irritation was
about the extent of it.
Some jellyfish aren’t so comparatively harmless, though. Some types can cause significant pain, or even kill people. The worst kind is the box jellyfish family, which is native mainly to the tropical Indian Ocean and western and central Pacific, although some species are found off the coast of
the Mediterranean Sea, South Africa,
and New Zealand. They are potent enough that during certain
times of the year beaches are closed because of their peak periods. And unlike most jellyfish, this type has true
eyes, and actively hunts its prey.
The absolute worst, though, is the subspecies of box jellyfish called irukandji (found mainly off the coasts of
and Malaysia, but
occasionally found in the waters off of Florida,
Japan, and even the British Isles).
This jellyfish can be tiny, less than the size of a person’s fingernail,
but packs a whallop. I can remember
seeing a nature documentary where scientists were studying it. Two of them accidently got stung while
diving, and the viewer got to see them writhing in agony in the hospital. Sufferers of what’s called “irukandji
syndrome” get symptoms like headache, nausea, sweating, vomiting, excruciating
muscle cramps, severe back and kidney pain, burning skin, and even a
psychological effect of feelings of impending doom. Another victim described the pain thusly; the
worst peak of pain during childbirth was like the minimum level of the
irukandji pain. This pain can last for
days, and lingering symptoms for weeks.
It’s not uncommon for sufferers to beg doctors to kill them to end their
misery. So, in closing, if you see a
warning about box jellyfish, or especially irukandji, in the waters where
you’re thinking of swimming, I’d emphatically heed them.
Even though they’re such a common sea animal, jellyfish don’t seem to be a very popular food item. Evidently only the Japanese, Koreans, and Chinese really like them. I’ve only seen them on the menu a few times, at Japanese and Chinese restaurants. The most recent time I sampled them was at the same place I had sea cucumber (see November 22, 2014 post). On the plate they look like clear whitish to light brownish strips of gelatinous flesh. Most are flavored with vinegar, and/or soy sauce. It wasn’t a strong taste, but it was okay. The texture was similar to that of seaweed salads in Japanese cuisine—soft, and (of course) jelly-like. Both times I had jellyfish as an appetizer, and I think that’s the best option. I think an entire dinner of it might be a little underwhelming. Good (but not spectacular), in small doses, every so often.
Finally, there are many folk remedies for easing the pain of jellyfish stings. Most prominent are vinegar and human urine. Both are ineffective, alas. In fact, application of these can actually make things worse. Evidently sea water can help somewhat, but otherwise you’ll just to wait it out. Recently, researchers have been working on a chemical to counteract the pain of even irukandji stings, which hopefully will prove effective, since waiting that one out is quite the ordeal. Furthermore, despite the awful descriptions of what happens during a box jellyfish, or irukandji sting, bear in mind that these stings are comparatively rare, and human deaths are seldom.