The venom of Irukandji box jellyfish (Malo spp.), the smallest jellyfish in the world with an average size of only one centimeter, have been proven fatal to humans (SF Fig. 3.3). Although the main bell of the box jelly is about the size of a sugar cube, its stinging tentacles can stretch for one meter (SF Fig.
The Australian box jellyfish is considered the most venomous marine animal. They may not look dangerous, but the sting from a box jellyfish could be enough to send you to Davy Jones's locker-a watery grave, that is.
Irukandji syndrome is a painful, potentially lethal condition caused by the sting and envenomation from multiple jellyfish species. It is characterized by severe pain, muscle cramping, hypertension, and potentially life-threatening cardiac complications.
Hannah Mitchell has miraculously survived a sting by an Irukandji jellyfish, one of Australia's most deadliest creatures. The teenager had been swimming near Goodwyn Island, off the Dampier Coast in Western Australia over the Easter long weekend when she was stung.
Irukandji-like symptoms can occur 20 – 30 minutes after the sting and include: severe pain in the body (back, abdomen and chest) increased heart rate (tachycardia) trouble breathing.
What are my chances of getting stung by an Irukandji? Rare. Out of the millions of “people days” each year in the Great Barrier Reef waters, in a particularly bad year, only around 100 Irukandji stings occur in Queensland which require medical treatment.
Irukandji jellyfish's stings are so severe they can cause fatal brain hemorrhages and on average send 50-100 people to the hospital annually. Robert Drewe describes the sting as "100 times as potent as that of a cobra and 1,000 times stronger than a tarantula's".
Wear protective clothing such as a full body lycra or neoprene suit, even if in shallow water, as most jellyfish stings occur when wading. This is the number one way of preventing stings, as suits protect up to 75% of the body and cover areas where stings more commonly occur.
Irukandji jellyfish are found mainly in the tropical waters of Australia; however, they have also been spotted as far afield as Africa, the Caribbean, and even Hawaii.
Though they're often referred to as "jellyfish eggs" these weird little creatures are called salps, and they have more in common with people than they do with jellyfish.
Irukandji Jellyfish (Carukia barnesi) At only 1 – 2cm in diameter the Irukandji may be the smallest jellyfish in the world but its tiny size doesn't take away from a reputation as one of the deadliest creatures of Tropical North Queensland's coastal and reef waters.
This includes marine stingers some of which are dangerous, most famously the box jellyfish and Irukandji. These can be found around Tropical North Queensland along the coast as far south as Gladstone, from around October/ November to May/ June.
There have been two confirmed Irukandji deaths in Australia. However, the mysterious deaths of several tourists on the Great Barrier Reef are believed to be linked to the stingers.
The Australian Resuscitation Council recommends the use of vinegar as first aid treatment for some jellyfish stings, including those that cause Irukandji syndrome (Australian Resuscitation Council 2010). Vinegar inactivates undischarged nematocysts of Box jellyfish (Chironex fleckeri) in experimental studies.
Irukandji are much smaller than their Box Jellyfish cousins. With their bell measuring a mere 2cm and their tentacles rarely reaching a metre in length, the Irukandji are incredibly hard to spot in water. People often do not feel Irukandji stings, and this leads to under reporting.
There are approximately 30 marine stinger enclosures on North Queensland beaches; most are operated by Uninet Enclosures. They have a mesh size of 25mm and are designed to exclude large box jellyfish. They do not exclude small segments of box jellyfish or irukandji.
Irukandji jellyfish are most likely found in tropical Australian waters, from Bundaberg in Queensland to Geraldton in Western Australia, from November to May, though incidents of Irukandji Syndrome in Far North Queensland have been recorded for all months of the year.
The Irukandji jellyfish is one of the smallest jellyfish species. On average, its bell, or main section, is less than one inch across! In addition, it is nearly transparent, which makes it extremely difficult to see in the water. This jellyfish has four tentacles, one attached to each corner of its square-shaped bell.
Jellies have long tentacles with lots of tiny stingers. Pieces of tentacles that wash up on the beach can still cause stings.
Anaphylactic Reaction to the Sting
A severe life-threatening allergic reaction is called anaphylaxis. The main symptoms are hives with trouble breathing and swallowing. It starts within 2 hours of the sting.
Identification. This species is the first discovered of what appears to be a group of Carybdeid sea jellies whose sting causes what is now called Irukandji Syndrome. Transparent, small and usually not observed, the Irukandji is unusual as its bell also features stinging capsules (nematocysts).