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Look Out for the Deadly Stingers!

Look Out for the Deadly Stingers!

 Look Out for the Deadly Stingers!


IT WAS a beautiful summer morning in northern Queensland, Australia​—a perfect day to bathe in balmy waters and escape the heat. But that morning the local radio station at Townsville broadcast frequent warnings that deadly box jellyfish had been sighted in local waters and that anyone going swimming that day should beware.

One young couple failed to hear these radio warnings. They were sitting quietly close to shore in about a foot and a half [50 cm] of blue Pacific water when the wife​—34 weeks pregnant—​suddenly screamed. Jumping up, she tried to pull several tentacles off her thigh and stomach. After helping her to struggle up to the beach, the husband​—also suffering from stings—​frantically ran for help. By the time he returned just a few minutes later, his wife appeared to have stopped breathing and her face and limbs were black. Happily, because of on-the-spot resuscitation and the prompt arrival of an ambulance, the young woman survived. So did her baby, who was born a few weeks later.

Hundreds of bathers are stung every year by box jellyfish. A few have died within one minute of being touched by the tentacles. Little wonder, then, that the sighting of a box jellyfish can empty the shoreline of summer swimmers in an instant! Its cluster of long tentacles​—40 to 60 in large specimens—​can be dangerous.

Are There Any Precautions?

Some choose to avoid swimming in the ocean at all when box jellyfish are about. But for those who do venture into the water during the warmer months, a full-body wet suit may be the best way to avoid a painful encounter.

Many northern Australian beaches are patrolled regularly, and whenever box jellyfish are spotted, most of them are netted. Additionally, frequent warnings are broadcast on the local radio station. Despite these precautions, there is always danger once the box jellyfish get on the move. They seem to spawn in tidal creeks and rivers. When mature, they appear to favor beaches.

Fortunately, the sting from the box jellyfish is usually not fatal. Much depends on the amount of tentacle contact, the amount of venom released, the maturity of the box jellyfish, and the age and health of the sting victim. Nevertheless, death by cardiac arrest can occur within a minute of contact with the tentacles if treatment is not given immediately. The  reason for this is that the tentacles have rows of stinging cells that are released like darts when they come in contact with other creatures. This, of course, is their way of obtaining food, such as prawns.

The box jellyfish has as many as eight eyes, which, even if facing inward to the transparent body, can locate an obstacle such as a human or predator. This does not mean that these jellyfish deliberately attack humans. No, for the box jellyfish maneuvers around the obstacle if it has enough time. It can do so using its box-shaped bell, which acts like a bellows, drawing in and expelling water.

The problem with humans is that they often run or dive into the water, giving box jellyfish no time to avoid collision. And when the tentacles come in contact with human skin, they react immediately​—clinging to the skin and releasing their venom. The pain experienced by the victim is intense. The venom is injected by many cells called nematocysts and is absorbed speedily. If the victim runs or thrashes about, absorption of the venom is speeded up. Another major problem is that although the tentacles break off from the jellyfish, they adhere to the victim’s flesh, and more venom is released if the victim attempts to pull the tentacles off.

An Antidote?

Yes, there is an antidote, and the prompt application of the correct antidote has saved many lives. For years it was mistakenly thought that the best emergency treatment to slow down the venom injection was to douse methylated spirits onto the tentacles clinging to the victim. Modern research, however, has revealed that the application of methylated spirits actually stimulates the discharge of venom.

It is now believed that vinegar​—a liquid that is cheap and quite readily available—​is the best solution to douse on tentacles. Vinegar completely inactivates the nematocysts and prevents them from discharging. Nowadays, then, most local councils in stinger danger zones place squeeze bottles of vinegar in prominent locations​—together with large marine stinger warning signs.

So while swimming in Australia’s warm tropical waters can be refreshing, even invigorating, during box jellyfish season, let the swimmer beware!

[Box/Picture on page 27]


• Swim only at patrolled beaches

• Wear a full-body wet suit in box jellyfish season

• Have a first-aid kit, including vinegar, close at hand

• If stung, do not try to pull the tentacles off

• If the victim’s heart or breathing stops, apply artificial resuscitation immediately

[Picture on page 26]

A close-up view of box-jellyfish tentacles

[Credit Line]

Courtesy of Surf Life Saving Queensland