These famous jellies are known for stinging and badly injuring or killing unsuspecting divers and snorkelers. While these nasty cnidarians do cause chaos, Australia is home to multiple amazing species of jellyfish that rarely sting but often amaze divers.
The moon jelly is the most common jellyfish in UK seas, often washing up on our beaches. No need to worry though - it doesn't sting humans.
Most people think that all gelatinous,swimming marine animal encountered at the sea are "jellyfish" and moreover that they all sting. But not all jellyfish are stinging; many are harmless to humans, but it is always best to avoid touching them.
The Irukandji has four tentacles, one on each corner, whereas the box has up to 15 tentacles coming from each corner. That's up to 60 tentacles all with millions of injection harpoons filled with venom.
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.
Comb jellyfish are completely harmless with no stingers.
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.
The first of these jellyfish, Carukia barnesi, was identified in 1964 by Jack Barnes; to prove it was the cause of Irukandji syndrome, he captured the tiny jellyfish and allowed it to sting him, his nine-year-old son and a robust young lifeguard. They all became seriously ill, but survived.
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.
Where the jellyfish tentacles have touched the skin, there will be immediate severe pain and red whip-like lines. If there has been a large area of contact, the person's heart may stop, causing death. This can happen within a few minutes.
Most often jellyfish stings cause instant pain and inflamed marks on the skin. Some stings may cause more whole-body (systemic) illness. And in rare cases they're life-threatening.
The Aurelia Aurita, known as the moon jelly, is the most common and widely recognized jellyfish species. Though it has venom, it is harmless to humans—it's even a popular dish in China!
Wear protective clothing. Covering skin with tight clothing and covering exposed areas (such as lips and face) with petroleum jelly will prevent many stings.
The Drymonema larsoni, commonly known as pink meanies, were first observed in the Gulf Coast in 2000. Scientists identified it as an entirely new species in 2011. These pretty pink jellyfish are carnivorous and have stinging tentacles that can reach up to 70 feet long.
Proud members of the sea squirt family, these amorphous blobs are essentially little water pumps, pumping water in and out of the bodies and extracting nutrients along the way. They also have a kind of primitive backbone, which jellies lack.
Habu-Kurage and box jellyfish are known to have extremely painful stings, Japanese sea nettle are moderately painful, and moon jellyfish are pretty much painless.
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.
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.
Similar to other box jellyfish stings, first aid consists of flushing the area with vinegar to neutralize the tentacle stinging apparatus. As no antivenom is available, treatment is largely supportive, with analgesia being the mainstay of management.
Irukandji Jellyfish Predators and Threats
The Irukandji jellyfish has few predators, as its small size and potent toxin make it difficult for other animals to eat. However, ocean sunfish, along with some sea turtles, fish, and sea snakes, are known to prey on the Irukandji jellyfish.
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.
Experts agree vinegar (due to its acetic acid content) is the best treatment for box jellyfish and their smaller cousins, the irukandji. The vinegar works by inhibiting the stinging cell discharge.
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.