People in coastal areas often ask, why are box jellyfish dangerous? If this is the same question in your mind, then here is some useful information.
Batul Nafisa Baxamusa
May 10, 2019
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Box jellyfish are known as the most venomous creatures in the world. They are frequently mentioned in Animal Planet documentaries as one of the 'deadliest' creatures lurking in open seas.
Many times, vacationers in Hawaii are often warned not to step into the ocean as thousands of these lethal jellyfish swim towards the coast. These jellyfish arrive near the shore 7 to 11 days after a full moon. But, why all these warnings? Because the Box Jellyfish is also known as the Box of Death.
These venomous creatures are very hard to spot and thus, it is better to stay away than get stung by their fatal stinging cells. But, why are box jellyfish dangerous? What makes their venom so dangerous? Let's go through a few box jellyfish facts in the next section.
The Box of Death!
Box jellyfish belongs to the class Cubozoa and have a characteristic cube shaped medusae. Some of the species of box jellyfish includes Chironex fleckeri, Carukia barnesi and Malo kingi. These species as well as a few others from this class cause an extremely painful sting that sometimes proves to be fatal to humans.
These venomous creatures of the sea are nearly invisible to the human eye. But, these creatures have fully developed true eyes to see. The eyes have a cornea, retina and lenses. They are located on all four sides in clusters. This means, though you can't see them, they can see you.
They have an umbrella shape and on the underside of this umbrella body is a velarium (flap). This helps in concentrating and increasing the water flow that is expelled from the umbrella. Thus, they are able to move faster than other jellyfish. They can move as far as 6 meters a minute.
They have a nerve ring at the base of the umbrella, that proves their nervous system is far more developed than other jellyfish. This nerve ring helps the jellyfish coordinate its pulsing moments. The box jellyfish habitat is largely restricted to the waters of the tropical Indo-Pacific oceans.
Some species are found in the Atlantic and east Pacific oceans. They can also be found as far as California, the Mediterranean and Japan. Some are even found all the way in the south of South Africa and down under in the waters of Australia and New Zealand.
What Makes Box Jellyfish Dangerous
A box jellyfish has about 60 tentacles that are 5 cm in length. These tentacles are arranged in 4 groups at the corners of the umbrella. They are covered with about 500,000 cnidocytes. These cnidocytes contain nematocystes, that are microscopic harpoon-shaped and can inject the venom into the victim.
The highest potency venom is carried by the jellyfish Chironex fleckeri, found in Australia. Since 1883, the C. fleckeri have caused over 64 deaths in Australia. Most of their victims have been children. This is because they have a smaller body mass and strength to fight off the effects of the venom.
Coming to the venom, it contains several toxins that attack the heart, nervous system and skin cells. It is so powerful and painful, that the victim goes into shock. This causes them to drown or die of a heart attack, before they get the chance to reach the shore.
The toxins include cardiotoxins that affect the heart, neurotoxins that damage the nerves and dermatoxins that destroys skin cells. The heart stops beating for a few minutes due to the effects of the cardiotoxins injected by three meters of tentacles. If it does not stop beating, the pain is unbearable and the victim will go into shock.
Thus, if swimming alone, he/she is bound to drown. The tentacles wrap around the skin tightly and continue to inject the toxins. If one tries to remove them, they will continue to sting and worsen the injury. This will lead to necrosis of the skin tissue.
Thus, survivors are often left with deep, scars to remind them of their horrific experience. This never-ending cycle of injecting toxins into the skin, pain and shock may lead to death in 5 minutes.
If a person does manage to reach the shore, s/he should be immediately treated. Most of the beaches where jellyfish are frequently seen, have vinegar in their first aid boxes. The victim, although in pain, should scream for help, if alone.
Friends or people on the beach should pour the vinegar on the site of injury all over the nematocysts. This will disable the nematocysts that have not yet injected the venom into the system.
Even if the jellyfish is dead or has been detached from the tentacles, they will continue to sting. So, make sure you drench the tentacles in vinegar as much as possible. Seek medical attention immediately, to help save the life of the victim.
Box jellyfish are very delicate creatures. Even a tiny little fish can tear through its body. They are aggressive hunters as opposed to other jellyfish that float. Thus, they need to develop a powerful venom that will kill their prey in an instant, before it causes any injury to them.
Maybe this is why box jellyfish are dangerous. As box jellyfish have eyes and can see, they tend to avoid humans. However, if they come across humans, they will accidentally wrap themselves around a leg which will lead to a fatal sting.
If you have been notified by the authorities, it is not safe to swim in the water on a particular day, please do so. Do not risk your life, especially when the invisible, Box of Death is lurking around.