Jellyfish might scare some people out of the water, but these most mysterious of ocean animals are an extraordinary sight

It is time to celebrate the beauty of jellyfish. Eerie and almost ethereal, they float through the ocean, rising and falling like the warmed wax blobs in a lava lamp. Officially, because it has no strong means of self-propulsion (beyond a lackadaisical expanding and contracting of its gelatinous skirts), the jellyfish is actually one big bit of zooplankton, subject to currents and upswellings, a nomadic organism roaming the world’s wide blue waters in a dreamy existence of its own.

Would it not be wonderful to be a jellyfish? British shores are being inundated by hordes of marauding jellyfish — this might scare some people out of the water, but to my mind, it is a welcome invasion by one of the ocean’s most mysterious animals.

Of course it can sting — how else would such an aimless creature feed itself, but by the happenstance of its colourful tentacles? That is part of its power in our imagination - its apparently insubstantial form, coupled with its potent effect. In Australia, for instance, should you merely brush against a box jellyfish (Chironex fleckeri), which can reach up to 3 m in length and is common off the shores of the Northern Territory, you could suffer cardiovascular collapse and death within two to five minutes.

The most notorious of all jellyfish in European waters is the infamous Portuguese man-of-war, Physalia caravella, so-called because it is supposed to resemble a naval ship at full sail. Yet even here the animal labours under a misapprehension, since the man-of-war is not actually a jellyfish at all, but a colony of zooids. It is also an exquisite creation, a clear, blue-tinged bladder, vaguely the size and shape of a rugby ball, with the addition of an outrageous purple frill.

Out with the sperm whales of the Azores, I’ve watched these beauties drift by, occasionally rather pathetically blown over by a gust of Atlantic wind. I’ve even held one in the air, its purple tentacles dangling like prolapsed piles, knotted and wobbling impotently before being lowered back into the water. One brush with those venom-filled nematocysts and I would be very uncomfortable indeed.

The beauty of jellyfish has acquired a sense of abstract allure; like butterflies, they seem to swim between art and science. In the mid-19th century, Leopold and Rudolf Blaschka, a father-and-son pair of Dresden glassmakers, created fabulously exact models of jellyfish, so realistic as to be barely distinguishable from the real thing.

Caught in the netherworld of the open ocean — is it a plant, or an animal? — the jellyfish’s ambiguity has the ability to unsettle. The moon jellies that I’ve seen assembling in Cape Cod Bay, for instance, resemble milky opals dropped into the blue-grey. They are a prime resource for turtles; indeed, the warming seas around the British Isles responsible for the recent presence of jellyfish are also encouraging loggerhead turtles, the largest of their kind, to make forays into the U.K.’s coastal waters, munching away on jellyfish much as people might work their way through a bag of sweets.

The most common jellyfish to be found British waters is the “common jellyfish” (Aurelia aurita), with the diameter of a dinner plate and four dangling “mouth-arms”, and crescent-shaped purple reproductive organs visible through its semi-transparent “umbrella”. It’s this jellyfish that people are most likely to see stranded at low tide in great numbers, as though someone had been engaging in a mass Frisbee-throwing contest. It can give you a nasty sting, but not much more than that.

Other jellyfish are blessed with wonderfully romantic names: the barrel, lion’s mane, compass, blue and mauve; and most evocative of all, the by the wind sailor, which is about as descriptive as you can get. The lion’s mane can get huge — its Arctic species can grow 150-foot-long tentacles, longer than a blue whale — and is the one most likely to cause severe problems to humans, resulting in cramp, and even heart and respiratory failure. The compass is another to avoid, only 20 cm in diameter, but capable of inflicting painful and long-lasting weals.

Portuguese men-of-war have been found on Britain’s south-west coasts — a couple of years ago I found a baby floating in a rock pool — but aren’t common. The best remedy for any sting is salt water (fresh water can makes things worse). Vinegar is a no-no; it can actually increase the effect of the venom. And while some people recommend peeing on the affected part, that is not only an unproved treatment, it’s also rather anti-social. Better to keep your distance, and watch these wondrous, ancient animals pulsate past, like ghostly Victorian brides in ectoplasmic crinolines. They are a truly extraordinary sight to witness ; a miraculous silent glimpse back into a primeval sea.

— © Guardian News & Media 2013

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