3 Dangerous Types of Aussie Stingers To Avoid And First Aid
Marine stingers inhabit all Australian coastal waters. Those in the tropical north are rated the most venomous creatures in the world.
In general terms, marine stingers are sea creatures capable of inflicting a venomous sting. This group may include stingrays, stonefish, lionfish, cone snails and jellyfish. This article focuses on jellyfish, in particular three species that pose a serious threat to bathers and boaters in Australian waters - box jellyfish, Irukandji and bluebottles. While the risk of being stung by one of them is statistically very low compared to the number of people in the water every year, the experience can be life-threatening and, at the very least, can ruin your holiday.
Box Jellyfish
Globally, the name box jellyfish is given to any of 50 species that are distinguished by their box-shaped body. In Australia, the name usually refers to the largest species found here, Chironex fleckeri. Their bell (head) is a rounded cube up to 30cm in diameter with a fleshy appendage at each bottom corner, from which trail as many as 15 ribbon-like tentacles three metres long. Both head and tentacles are typically colourless and translucent, making them difficult to spot in the ocean. The bell’s shape creates a powerful jet when it pulsates, enabling the jellyfish to swim at speeds up to four knots (7kph).
Each tentacle contains millions of nematocysts - microscopic darts that are triggered on contact with the victim’s skin and inject venom. The stings cause immediate, severe burning pain, and produces white welts at contact points, followed by red whip-like lines which may later blister and leave deep, permanent scarring.
Minor contact can induce secondary symptoms of sweating, anxiety, nausea and vomiting. A severe sting with massive envenomation can cause respiratory distress and cardiac arrest within just a few minutes, proving fatal to an untreated victim. For this reason, the box jellyfish is widely regarded as the world’s deadliest venomous creature. In Australia, Chironex has claimed 81 lives, the most recent being that of a 14-year-old boy who died after being stung while swimming at a beach near Mackay in February 2022.
Irukandji
Irukandji is a group of box jellyfish that are very small, usually no bigger than a human thumbnail, but extremely venomous. Of the 16 known species, those most commonly found in Australian waters are Carukia barnesi, Malo kingi and Malo maxima. They differ from their larger Chironex cousins in having only one tentacle of about one metre from each corner of the bell, as well as stingers on the bell itself. While some species of mature Irukandji have light purple halo-like rings around the tentacles, they are generally colourless and transparent, making them almost invisible in the water.
Though rarely lethal, Irukandji venom is highly toxic and insidious in effect. Victims may not even feel the initial sting, which is rarely evident apart from a mild irritation of the skin at the site. However, within about 30 minutes the victim will succumb to a constellation of acute symptoms known as ‘Irukandji Syndrome’.
These include severe backache and headache, shooting pains in the muscles, chest and abdomen, nausea, vomiting, profuse sweating and difficulty breathing. In severe cases, the victim may also suffer very high blood pressure leading to heart failure or brain haemorrhage. Two fatalities have been attributed to Irukandji stings in Australian waters, and the syndrome requires hospitalisation in about 100 cases annually.
Bluebottles
Also known as the Pacific man-o-war (Physalia utriculus), the bluebottle is not a true jellyfish but a siphonophore, a colony of tiny organisms (zooids) working together as a single animal. Thousands of these animals congregate in masses called ‘fleets’ or ‘armadas’ that float on the surface of the ocean, drifting at the mercy of the wind and currents.
A bluebottle is comprised of four kinds of zooids, each performing a specialised function and depending on the others for survival. The species takes its name from one of them, the distinctive blue, gas-filled sac (pneumatophore) that floats on the ocean surface. Attached beneath the sac, the other zooids are responsible for catching and digesting prey and reproduction.
Growing to between two-10 centimetres long, the sac is bottle or pear-shaped, with a slender ridge along its upper margin that acts like a sail. On different individuals, the sail is curved either to the right or to the left, determining its angle of travel before the wind - the same wind will push the two variants in different directions, preventing the entire fleet being washed ashore and dying.
The bluebottle trails a single tentacle up to three metres long armed with thousands of tiny nematocysts that trigger and inject venom on contact. For an estimated 30,000 Australian beachgoers every summer, the venom inflicts a painful, burning sting with a distinctive beaded white welt. While the sting is not lethal to the average adult, it may produce an allergic reaction (anaphylaxis) in some people or children, requiring immediate medical attention.
Distribution
Box jellyfish and Irukandji occur in shallow tropical waters around the world. In Australia, they are most common in estuaries and beaches on the northern coastline from Agnes Waters (Qld) to Geraldton (WA). The southern extent of Irukandji on the east coast has been gradually moving south, to encompass sub-tropical and temperate regions including Fraser Island, Moreton Bay, Sydney and Melbourne. Although they live in pelagic waters, they may appear in epidemic proportions close to shore, which presents a real hazard to swimmers. Bluebottles are found in all the world's oceans, in tropical, subtropical and temperate regions. They occur all around Australia’s coastline but are more common on exposed ocean beaches south of Bundaberg (Qld) on the east coast and below Geraldton in the west.
Stinger Season
While tropical stingers may be present throughout the year, they are more active and more numerous during the warmer months of November to May (October to June in the Northern Territory). This is considered the ‘peak season’, when juveniles leave the sheltered estuaries and move into coastal waters to forage. Bluebottles are commonly encountered in the summer months on the east coast, and during autumn and winter in southern Western Australia, when strong onshore winds blow armadas onto exposed ocean beaches.
Avoiding A Sting
The best way to avoid a sting from a box jellyfish or Irukandji is to stay out of the water where they may be lurking, especially during the ‘stinger season’. But if you simply can’t resist the lure of those sparkling tropical waters, there are some things you can do to prevent, or at least minimise, the risk of a nasty injury.
Be aware of high-risk conditions, such as sustained onshore winds, flat seas, calm weather, ‘sea lice’ or larval fragments in the water or on the tide line. (Don’t touch marine stingers washed up on the beach, they can still sting you.)
Check signage and local warnings for stinger presence. If a beach is closed it’s probably for a good reason.
Never go into the water when the beach is closed, help may not be on hand should you get into trouble.
Always swim at patrolled beaches between the red and yellow flags and inside stinger nets if they’re provided. Within the enclosure, keep away from the edge and don’t submerge the floating pontoon as a stinger may wash over the top. (Enclosures are not effective against Irukandji or fragments of Chironex, which are small enough to pass through the nets.)
Enter the water slowly. Box jellyfish will often swim away if given the time and opportunity to do so.
Wear protective clothing. A full-body lycra or neoprene suit is best but any clothing, however thin, will provide a measure of protection as long as there are no gaps or exposed skin. The more coverage and tighter the weave and fitting, the greater the protection. (Stings may still occur on hands, feet and face.)
Always carry vinegar when boating or undertaking other marine activities in stinger areas, in case of emergencies.
First Aid For Tropical Stings
Chironex and Irukandji stings are potentially life-threatening, and it is vital to provide effective first aid as soon as possible.
Bring the patient to the beach as quickly and safely as possible.
Call (000) for an ambulance and seek assistance from a lifeguard, if available
If the victim is unconscious, commence cardiopulmonary resuscitation (CPR) immediately.
Pour vinegar liberally over the affected skin for at least 30 seconds to deactivate the stinging cells and prevent them from injecting more venom. Vinegar is made available on many Australian beaches in marine stinger zones.
If you don’t have vinegar, wash thoroughly with sea water.
Do not wash with fresh water or substitute vinegar with methylated spirits or alcohol because they will make the sting worse.
Remove any remaining tentacles with a towel or gloved hand to prevent secondary stinging. (Do not use bare hands.)
Immerse the affected area in hot water (no hotter than the rescuer can comfortably tolerate, say 40-45 C), or apply a hot pack, 20 to 45 minutes.
If the pain is unrelieved by heat, or if hot water is not available, apply cold packs or ice in a dry plastic bag
Reassure the patient and keep them calm until medical help arrives.
Treatment Of Non-Tropical Stings
Stings by bluebottles and other non-tropical jellyfish are generally not life-threatening but may still require some first aid to relieve the victim’s pain and anxiety and to safeguard against unusual complications such as anaphylaxis.
If stings cover a large area or across the throat and face, call (000) for emergency assistance.
Rinse the affected skin liberally with seawater.
Do not scrub with sand or rinse with vinegar or freshwater.
Remove any adhering tentacles with a towel or gloved hands.
Immerse the affected areas in hot water or apply heat packs for at least 20 minutes.
If the pain is unrelieved by heat, or if hot water or packs are not available, apply cold packs or ice in a dry plastic bag.
Seek medical attention if pain persists or the victim develops symptoms consistent with an allergic reaction.