BushwalkBushwalkThere are a lot of marine creatures that bite or sting, an evolutionary development to defend and hunt underwater. Some deliver venom via spines, tentacles or teeth, while others aren’t venomous but have sophisticated teeth for attacking prey and defending themselves (e.g. sharks).
The most common marine stings are from jellyfish, mainly bluebottles, followed by spiny fish and stingrays. Box jellyfish are the most dangerous, but only found in the tropics. Likewise blue-ringed octopi and sea snakes pose significant risks, but are attacks are uncommon.
We can split marine species into a few groups: animals that are lethal and non-lethal (i.e. those that give a painful bite)
HIGHLY VENOMOUS
- Box jellyfish (Cubozoa)
The box jellyfish is the most venomous animal in the world and can cause cardiac arrest within minutes. Box jellyfish are a significant threat, but in the tropics only.
- Blue-ringed octopus (Hapalochlaena)
The blue-ringed octopus is a small but deadly creature with enough venom to kill 26 humans. Bites are often painless, resulting in victims not being aware that they’ve been bitten until severe symptoms set in. To make matters worse, there is currently no blue-ringed antivenom, putting it high on the list of deadliest marine creatures.
However, whilst blue ringed octopus venom is deadly there have only been three deaths in the last century, two in Australia. It’s most important though to avoid turning over rocks in shallow water, especially with bare hands as this is when you can be bitten.
- Sea snakes (Hydrophiinae)
Although the majority of sea snakes are highly venomous, venom injection is rare and very few human fatalities have been reported. They are another species that is only found in tropical waters. Under these conditions, be wary of sea snakes and manage all bites as though venom has been injected. Nevertheless, be wary of sea snakes and manage all bites as though venom has been injected.
- Irukandji jellyfish
Irukandji are small jellyfish with four long tentacles. Their tentacles can be as small as few centimetres long up to 1 metre. Victims report excruciating pain that is delayed starting for 5-120 minutes, but can last for months. Although often hospitalised, fatalities are rare (3 reported over the last 100 years).
News.com.au reports the following experiences from a victim:
- “I cannot begin to explain how excruciating the pain is,” jellyfish toxicologist, Professor Jamie Seymour of James Cook University, told news.com.au.
- “I’ve been stung 11 times and each time I’ve ended up in hospital.
- “It’s very mild to start with, then it takes about 15 to 20 minutes to kick in and it’s overall mind-numbing horrific pain.
- “The last time I got stung across the top of my lip, then I got pins and needles in my feet, pain like red hot pokers in my joints and then overwhelming racking body pain and throwing up for 18 hours.”
Whilst Irukandji stings are historically rare,there are concerns that the threat is increasing and heading further south from the tropics. It is hard to know as Irukandji stings are often difficult to prove as the animal is so small and symptoms are delayed.
- Stonefish (Synanceia)
Stonefish are highly venomous and can be fatal if not treated. Often, stings are the result of accidentally stepping on the fish as it is well camouflaged against rocks and coral. Amazingly, stonefish are able to stay out of water for up to 24 hours, so it’s possible to get stung by an individual washed up on the beach. Stonefish antivenom is the second-most administered in Australia.
- Scorpion fish
Scorpion fish are found in shallow waters around Sydney and are often seen by divers. They have sharp spines coated in a venomous mucus that stings and a puncture to the chest or abdomen may be fatal. Scorpionfish are the most likely animal to cause a painful sting in NSW as they are so common. They are rarely fatal but the sting is debilitating. You are most likely to be stung by putting your hand on one accidentally – so when in the water don’t touch!
VENOMOUS
Here, we list species that tend to give painful to excruciating bites, but are generally non-leathal. However, be warned, without appropriate medical action, each species still has the potential kill (e.g. patient experiences a severe allergic reaction, breathing difficulties, or has small body frame – children at risk).
- Blue-bottle (Pacific Man-O-War) jellyfish (Physalia physalis)
Blue bottles are common throughout marine areas of Australia, and an unwelcome guest for beachgoers. Bluebottle threat is mostly when there is an onshore breeze as this blows the animals on to beach areas. They are between 2-15 cm, and more common on exposed ocean beaches rather than protected waters. A sting, while uncomfortable, is not life-threatening, however, for the very young or elderly there may be medical complications. Avoid the temptation to poke or play with washed up bluebottles as stinging cells in the tentacles may still be active.
- Jimble jellyfish (Cubozoan)
Although related to the Box jellyfish, the Jimble jellyfish is nowhere near as potent. It is the only Cubozoan that lives in colder Australian waters, and is occasionally present in high densities in Sydney Harbour.
- Coneshells
Brightly coloured coneshells are armed with small harpoons that can sting. Although most stings are no worse than a bee sting, in Australia, there are tropical species that have caused human fatalities. Hence, all species must be treated as potentially dangerous.
- Catfish
Catfish are recognised by their distinctive whiskers around their mouth. They also have sharp, bony spines on the edges of the dorsal and pectoral fins with venom that lock into place when they are threatened. Catfish stings are extremely painful at the site of the sting.
On the east coast of Australia, the best known species is the eel tailed catfish, which occurs in coastal rivers.
- Crown-of-Thorns starfish (Acanthaster planci)
Crown-of-Thorns has a very wide Indo-Pacific distribution, and is increasingly common around Australia. Crown-of-Thorns lives on corals so it is only found in northern NSW. Since the 1960s there have been population outbreaks where overabundance of the starfish put pressure on the coral species they feed on and coral goes into decline. Overpopulation of the starfish is a concern for vulnerable coral with slow regeneration rates.
This starfish has spines that can perforate human skin causing sharp pain, persistent bleeding, tissue swelling and nausea. Embedded spines need to be removed surgically.
- Stingray (Myliobatoidei)
Stingrays have stingers on their tails that can cause pain, swelling, muscle cramps from the venom. Although death is rare, is can happen. Most famously, Steve Irwin was killed in 2006 when the stinger penetrated his thorax.
The Black Stingray is one of the largest stingrays in Australia, and is found off the coast of Sydney. Although venomous, they are not usually aggressive towards humans. This video beautifully captures how the stingray moves in water: https://www.youtube.com/watch?v=VPfXvWrVK3Y&feature=youtu.be
Stingrays and stingarees are only dangerous if provoked, that is, if you grab them or accidentally tread on them. If walking in shallow water shuffle your feet sideways rather than stepping high – this moves them out of your way if they are around.
- Sea Urchins
A relative of starfish, sea urchins are found on coral reefs, rocky shores and beaches. They feed on plant matter growing on ocean surfaces, or burrow to find decaying matter. Black Sea Urchins (Centrostephanus rodgersii) are the most common species found in Sydney waters and are recognised by their distinctive black spikes.
The mostly likely injury from any urchin species is a spine in you, especially from a black urchin as they are super-abundant in swimming, snorkeling and diving areas around Sydney.
The Toxic flower urchin (Toxopneustes pileolus) has also been sighted around Sydney. It’s considered dangerous as it can deliver medically significant (and extremely painful) stings when touched – avoid touching!
Other venomous urchins include Diademas and Sea lamingtons (Tripneustes gratilla).
Diademas look very similar to the Black Sea Urchins, but are distinguished by the blue v-shaped flecks on the body and their much sharper, longer spines. Their spines have venomous tips.
Sea lamingtons (Tripneustes gratilla) are usually found in tropical waters, however, they have been sighted in Sydney harbour. In general, they are a common, but not dangerous species.
OTHER
- Shark Bites
Shark encounters are incredibly rare, and when they do occur, often attract significant media attention. Thus, the risk of attack often appears much higher than it actually is.
Data from the Australian Shark Attack File (ASAF) on shark attacks over the last 20 years, shows that shark fatalities remain low, at 1 fatality per year[1]. West 2011 also highlights that the seeming increase in attacks is related to an increasing human population and therefore increased water-use for recreation: “The increase in shark attacks over the past two decades is consistent with international statistics of shark attacks increasing annually because of the greater numbers of people in the water”.
Most shark species are not dangerous. Even large species like the grey nurse shark (Carcharias taurus), where females can reach up to 2.2 m in length. It’s commonly thought that shark attacks on humans are mostly a case of mistaken identity; sharks thinking that a human is something else like a seal for instance (surfers from below resemble the shape of seals), and taking an exploratory bite. In most cases, the shark does not come back after one bite, and less than a third of attacks are fatal.
The Australian government has the following recommendations for avoiding marine bites and stings:
- Swim at patrolled beaches between the red and yellow flags and inside stinger nets if they’re available.
- Don’t enter the water when the beaches are closed.
- Wear a full-body lycra suit for extra protection (particularly from tropical stingers during stinger season).
-Don’t touch marine stingers if they are on the beach – they can still sting you.
- Enter the water slowly to give marine stingers time to swim away.
- Ask a lifeguard for help or advice if needed. While Box jellyfish are a significant threat, it can be reduced by covering up all bare skin (like wearing a thin rash suit) and in some areas swimming is simply avoided during the threat period (spring and summer).
- Additional advice: Do not deliberately provoke, disturb or touch marine wildlife.
- Avoid turning over rocks in shallow water, especially with bare hands – this is when you can be bitten by animals like the blue ringed octopus.
- If walking in shallow water, shuffle your feet sideways rather than stepping high – this moves Stingrays and stingarees out of the way if they are around and resting on the seafloor.
- Obey instructions from lifeguards and landmanagers – do not enter the water if beach is closed.
After any marine bite or sting, seek medical help immediately if you experience:
- Difficulty breathing
- Difficulty remaining conscious
- Chest pain
- Swelling around the sting site
- Vomiting
- Spasms
- Shock
- Severe bleeding
For stingrays, symptoms include intense pain, nausea, weakness, and fainting. For tentacled creates, symptoms are rashes, blisters, headaches, chest pain, muscle pain, sweating and runny nose. For coneshells, reactions include swelling, numbness, blurred vision, and respiratory failure. In rare instances, a person may experience cardiac arrest.
Adapted from St John’s Ambulance guidelines.
Pressure immobilisation (Funnel-web and Mouse spiders, snakes, Blue-ringed octopus, coneshells, sea snakes)
1 Follow DRSABCD.
2 Calm patient and keep still.
3 Apply a pressure immobilisation bandage.
4 Ensure call for help has been made—triple zero (000) – or emergency beacon activated.
Cold Compress (bees, wasps (European), ants, ticks, scorpions, centipedes, Red-backed spider, all other spiders)
1 Follow DRSABCD.
2 Calm patient.
3 Apply a cold compress or ice pack directly over the bite site to relieve the pain.
4 Seek medical aid if necessary.
Hot Water Treatment (Blue-bottle (Pacific Man-O-War) jellyfish, Bullrout fish, Catfish, Crown-of-Thorns starfish, Stingray, Stonefish, non-tropical minor jellyfish)
1 Follow DRSABCD.
2 Calm patient.
3 Place patient’s stung limb in hot water (as hot as you, the first aider, can tolerate).
4 Ensure call for help has been made—triple zero (000) – or emergency beacon activated.
Vinegar Treatment (Box jellyfish, Irukandji jellyfish, Jimble jellyfish, sea anenomes, tropical marine stings of unknown origin)
1 Follow DRSABCD.
2 Calm patient.
3 Flood stung area with vinegar for at least 30 seconds.
4 If vinegar not available, flick tentacles off using a stick or gloved fingers.
5 Ensure call for help has been made—triple zero (000) – or emergency beacon activated.