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The Box Jellyfish

Some species of box jellyfish produce extremely potent venom.

By Christina Albright-Mundy

For me, jellyfish are wonderment; watching them pulse through the water is a Zen experience. I remember the first time I jumped into an ocean full of sea nettles. “It’s only uncomfortable if they sting you,” my instructor called out. And for the sea nettles, he was right — it was like rubbing against attic insulation, more annoying than anything else.

A few months after that encounter, I was on a night dive in Roatan, Honduras. To conserve air, my buddy and I decided to snorkel to the descent line. There was enough moonlight that we didn’t need our dive lights; in the shallow water we were able to clearly make out the buoyed PVC pipes directing our path. I was following behind my dive buddy when I felt as though something was burrowing beneath the skin of my left forearm — I’d foolishly worn only a 3 mm shorty in these warm Caribbean waters. I shook off the pain and continued my swim, only to feel the same pain in my right arm and my right calf. I stopped short and spit out my snorkel to identify my attacker. Small, nearly invisible jellyfish pulsed before my eyes, their tentacles responsible for the searing pain I was now feeling in my leg. We descended to escape the surface assault, the pain being mostly manageable and not worthy of calling off a dive. I learned a few important things that night, that you should always wear dive skins under a shorty and that it’s impossible to treat yourself homeopathically underwater, if you know what I mean.

And while those harmless box jellyfish were capable of taking my breath away with their stings, there are far more dangerous jellyfish in the sea. The Chironex fleckeri is a box jellyfish found in the warm ocean waters off Northern Australia, Southern and Eastern Asia, the Gulf of Mexico, New Guinea, the Philippines and Vietnam. With a bell that can grow to be over 1 foot in diameter, these animals can have up to 60 tentacles, capable of growing to lengths of over 9 feet each. And each of these tentacles is outfitted with millions of nematocysts, stinging barbs used for self-defense, capturing prey and stinging unsuspecting divers.

As with all venomous creatures, the amount of venom the victim receives determines the damage done by the jellyfish sting. A person would have to make contact with the equivalent of  20 feet of Chironex fleckeri tentacles, with all nematocysts firing, to receive a fatal sting. But lest you think that coming into contact with 20 feet of jellyfish tentacle is far-fetched, know that this animal is responsible for over 100 deaths in the last century. With one jellyfish capable of killing 60 men, the box jellyfish has more than earned its title as the world’s most venomous animal.

Understanding how the Chironex fleckeri’s venom works is an important step in preventing death or alleviating suffering. Dr. Angel Yanagihara, a biochemist at the University of Hawaii at Manoa, John A. Burns School of Medicine in Honolulu, Hawaii, specializes in venomous jellyfish research. In December 2012, Dr. Yanagihara discovered how the Chironex fleckeri venom kills its victims, by causing cell walls to become porous, thereby allowing stored potassium to leak into the blood stream. This leads to the development of hyperkalemia, or excessive levels of potassium in the bloodstream, and can cause rapid death.

Within five minutes of being stung, victims suffer extreme pain, shortness of breath and may experience cardiac arrest. Death can occur in as little as three minutes.  Having come in contact with a victim with Chironex fleckeri venom, prompt medical attention is essential.  While waiting for EMS to arrive, the inflicted area can be treated with vinegar, which has been shown to inhibit the activation of any unfired nematocysts.  Any visible tentacles can be removed with tweezers or gloves, but never with bare hands. Until EMS arrives, the victim must be monitored for signs of deterioration and, if necessary, given CPR.

Before writing off your dream trip to the Great Barrier Reef, know that there are preventative measures for Chironex fleckeri — and all jellyfish stings. In order to trigger a release, nematocysts need pressure, as well as the presence of a proteinous chemical, such as the one that is contained in our skin. Without access to this chemical, there is no release of the nematocysts and no sting. Dive skins and the Australian-marketed Stinger Suit are great at covering large swaths of skin, as are gloves and boots. Pantyhose are also effective in the fight against jellyfish stings.

Another trick for the diver’s bag is to use the color red. Australian marine biologists conducted multiple experiments using a Chironex fleckeri jellyfish and an Irukanji jellyfish (a venomous cousin of the Chironex fleckeri). To determine whether their eyes were able to detect or avoid a hazard, the experimenters placed two poles in a tank with of each of these jellyfish. The animals did not appear to see black poles and repeatedly ran into them, while they swam around white poles, showing some level of awareness to their presence. When red poles were placed in their tanks, the jellyfish avoided all contact with them, relegating themselves to the far reaches of their tanks. So if you’ve got a trip planned to the Indo-Pacific or to Australia, it might be time to hit up your local drugstore for some red pantyhose — safety before fashion.