The Great Barrier Reef is the largest and most beautiful coral reef in the world with several varied colorful species of marine life. However, if you plan to make a trip there, remember that it also is home to the world’s most poisonous creature, the chironex fleckeri, commonly known as the box jelly fish. At times, it is also known as a sea wasp. Their sting can be extremely painful and can cause instant death. A minimum of 63 human deaths have already been recorded till date in Australia due to box jelly fish.
Box jelly fish is transparent, pale blue and cube or umbrella shaped, but has 4 sides, and hence, the name. An adult can attain a size of a basketball and may have up to 60 tentacles, each around five meters long and positioned in clusters around the four corners of their body. These tentacles are studded with nearly 5 million cells that are used for stinging prey and for defense. These cells are known as nematocytes, which get activated when the arms of the jellyfish touch certain prey that have specific chemicals on their bodies.
This jellyfish has a keen vision with 24 eyes, distributed in clusters on each of its four sides. Some of its eyes are complete with retina, cornea, lens and an iris that have the ability to contract as well as dilate. They are very swift and can attain a speed of 4 knots using their water propulsion mechanism.
Defense and Food
Box jelly fishes feed on small crustaceans and fish, such as crayfish, shrimp, and baitfish. The venom from their tentacles is used for catching prey as well as for defense from their enemies, such as butterfish, batfish, rabbit fish and crabs.
Box jellyfishes prefer to be in shallow waters and nearby beaches. They are often found near river mouths, bays and creeks particularly after a rain shower. They avoid wandering towards deep, rough waters. During high tides, they shift to shallow waters. Coral reefs and places with too many sea weeds or grass are never the best places to find them.
Research shows that the number of humans killed by box jelly fish is relatively higher than a collective kill percentage of stonefish, sharks, sea snakes and even crocodiles. In northern parts of Australia, the box jelly fish is found primarily from October to May, whereas further south, towards Northern Queensland or North Western Australia, the box jelly fish is present between November and March.
It is recommended to be careful while walking on the sandy beaches in these regions, as accidentally stepping on their tentacles can cause sudden death. Avoid swimming or surfing in the waters, especially during the peak months unless the beach is enclosed by stinger nets. It is advisable to adhere to the precautionary measures throughout the year as few cases are reported off-season also. Make sure that you wear swimming gears designed for protecting you against them and never go swimming alone. Importantly, educate yourself on how to administer first aid on yourself or another person if stung by a box jelly fish.
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