By Rosemary Jilderts

Our Great Barrier Reef waters are home to many beautiful creatures that present no danger when we venture into their habitat; however, there are a number that can cause injury ranging from mild skin irritations to, in rare cases, death.  To enjoy your time with us in Queensland in safety it is wise to be able to recognise them so that you can avoid them and in the unfortunate event of a sting or bite you will know how to administer first aid.  With knowledge comes safety. 

In this, the third and last instalment on dangerous marine creatures we will be looking at Moray Eels, Cone Shells, Fire Coral, Hydroids, Sea Urchins, Sea Anemones, Crown-of-Thorns Starfish and Blue-Ringed Octopus.

Moray eels

Despite their similarity in appearance to a snake, moray eels are actually fish.  They have a long, slender body with one long fin extending from head to tail with a large set of jaws.  Most reach a length of one to two metres although some species will grow to three metres and 30cms in diameter.  Colours vary from black to brownish-yellow with a pale belly.  The Giant Moray reaches almost three metres and can weigh over 36kg. This species is mostly brown with dark brown spots. The head is yellow to brown and the gill opening is surrounded by a black blotch.

Nature has many innovative mechanisms for ensuring an animal’s meal does not escape and that it moves rapidly along the digestive track.  Most fish use suction to draw in their victims.  Some- but not all – eels feed this way, but scientists at the University of California discovered that at least one species of moray has a mobile inner jaw that is lined with razor-edged, hook-like teeth.  This inner jaw can be thrust forward at very high speed into the mouth thus virtually eliminating any prey’s chance of survival. 

Morays are carnivorous and their prey includes other fish, cephalopods, molluscs and crustaceans.  Amongst their few predators are other morays, gropers and barracudas.

Morays prefer to live in warm water to depths of 150m where they hide in crevices in the reef.  They anchor themselves with their tail leaving the snout visible and the mouth open wide.  This is not a threatening gesture but  enables them to breathe.  Morays mainly come out at night, although they may catch small fish and crustaceans that stray too close to their hole during the day.  

While often considered cranky, morays are actually shy and hide from humans, preferring flight to fight.  On the rare occasions that they have bitten a human, it is believed to have been either accidental or in self-defence.  Morays rely on their keen sense of smell as their sight and hearing is poor so when divers are hand-feeding these animals the risk of sustaining a bite is obviously quite high. Larger morays can inflict serious wounds to humans. 

For many years divers at the Cod Hole at the Ribbon Reefs 10nm from Lizard Island enjoyed interacting with the two resident moray eels with regular feeding being a popular highlight of dive tours.  In the 1990’s while John and I were on one of our regular cruises through the area we heard of a British backpacker, working on a well-known dive charter boat, who had been bitten on the arm as she attempted to feed one of the morays.  She was quickly despatched to hospital where the arm was amputated due to loss of muscle in the limb.  As we sat on anchor one night listening to the VHF radio we overheard a conversation between Lizard Island Research Station and a Marine Parks Officer who was on his way to the island by boat.  The conversation led us to believe that the offending moray had been ‘despatched’ and was being held in the freezer pending the officer’s arrival and the second moray would be ‘relocated’.  Death for the offender; banishment for the ‘accomplice’.

Morays inflict a nasty bite and although not poisonous their teeth are covered with bacteria so secondary infections are a concern.  Wounds from moray bites usually bleed heavily.  Ciguatera poisoning is also possible if this eel is eaten. 

Despite this the moray eel still has friends including small shrimps and wrasses – the ‘cleaners’ of the ocean – that clean off and also feed upon the parasites and bits of food that remain in the moray’s mouth.

Divers can avoid bumping into morays by maintaining proper buoyancy control so that they swim just above the reef.  Grabbing a handhold on coral or rocks should be avoided – in part to avoid damage to the reef but also to avoid the risk of a moray getting defensive and grabbing hold of you.  Despite the popularity of handfeeding all types of fish, my advice is – don’t.

First Aid
Cleaning the wound thoroughly is the most important action to take.  Wash it thoroughly under a tap and disinfect the wound.  If the wound is turning red or swelling badly visit a doctor for treatment rather than running the risk of septicaemia.

Large wounds can cause loss of tissue and blood and will need medical care.  In the case of heavy blood loss, the affected limb may have to be ligatured until help arrives.

Cone shells

Cone shells (Conus spp.) are among the most abundant and beautiful coloured gastropods inhabiting marine waters.  There are many species occurring in temperate and subtropical waters but the vast majority live in the Indo-Pacific’s tropical regions.  While different species of cones grow to varying sizes the Geographic Cone shell, which is highly prized by shell collectors for its intricately patterned brown-and-white shells, is indigenous to the Indo-Pacific region and can grow to 15cms in length.

These predatory gastropods inhabit mostly mud, sand flats and shallow reef waters that are affected by the tides but there are some species that live to depths of up to 30m or more. Cones become active at night; during the day they bury under coral, stones or in the sea-bed. 

Most cone shells live in the Indo-Pacific region in temperate or tropical waters where the water temperature is between 22°-29°C, but there are others that live along the country’s southern coast in water temperatures of only 5°-12°C.  The latter are generally the smaller varieties.

Numbers vary with expert sources quoting anywhere between 300 and 600 species worldwide however, Australian waters support approximately 80 species.

The animal lives inside its brightly coloured and intricately patterned shell which is very attractive, especially to unwary children.  The foot which appears at the bottom of the shell is used for movement.   The animal has a siphon which draws in water for it to breathe and a tooth (used for hunting and defence) which can penetrate clothing.

These shells, and especially the rarer species, are popular with collectors despite the fact that the larger varieties are dangerous with a small number of human fatalities being attributed to them.  Collectors should be aware of the dangers.  They should also be aware that in some Qld. Marine Park Zones the taking of any marine animal is prohibited.  Always check the department’s zoning maps before travelling in Queensland waters.

Cone shells – also known as the cone or marine snail - can be found in reef environments throughout the world.  Their natural diet comprises other marine organisms which they immobilize with their unique venom.  Thirty cases of human envenomations by fish-eating cone shells have been recorded world-wide some of which have been fatal.  However, the cone shell venom also possesses pharmacological qualities that make them extremely valuable for medical research.

Cones – depending on the species – feed on worms, molluscs or fish. 

The most common of the cones are the vermivores which are worm eating.   Vermivores are usually small – often only one centimetre – and are relatively harmless to humans.

Molluscivores are larger than the vermivores and feed on molluscs as their name suggests.  Their prey is paralysed quickly and is eaten in the shell.  The venom or digestive juices – which are regurgitated from the animal’s proboscis – probably help to break down the prey’s body tissues.

Piscivores are the largest of all the cones.  Their elongated teeth can be up to 20mm long.  A radular tooth is forced into its prey and venom is injected and a sphincter muscle at the tip of the proboscis holds the tooth firmly in place.  When the fish has stopped struggling, it is swallowed through the proboscis which may dilate up to two centimetres in diameter.  If the cone’s first hit is not successful a second tooth can quickly move into place for another attack.

Of this species the most dangerous and the one responsible for a number of deaths is the Geographic Cone.  Another species, the Textile Cone, has also been blamed for some fatalities but this may have been a case of misidentification and possibly the real culprit was the Geographic Cone. 

The Geographic Cone is nicknamed the ‘cigarette snail’ which is a humorous exaggeration meaning that anyone stung by one would have just enough time to smoke a cigarette before dying.  Two other ‘fish-eaters’ with strong venom are the Tulip and Striated Cones.

There is no antivenin for a cone sting.  Treatment is limited to keeping the victims alive until the toxins wear off.

Ironically, the cone venom contains proteins which after being isolated have enormous potential as pain-killers.  Some of these proteins which will target specific human pain receptors can be up to 10,000 times more potent than morphine without that drug’s addictive side effects. 

Symptoms
Immediate local pain is followed very quickly by numbness or tingling in the area surrounding the sting.  Within about five minutes, more symptoms become apparent.  All extremities will be gradually affected by numbness, redness and swelling.  The victim will experience dizziness, vomiting and sometimes severe pain.  Other symptoms such as respiratory difficulties, paralysis, extreme dizziness and inability to focus the eyes may be followed by difficulty in talking and swallowing.

Sea anemones

Anemones are marine animals despite resembling beautiful underwater flowers.  They live on and around our reefs and come in a variety of colours such as red, mauve, blue, green and white.  Their wavy tentacles are home to the lovable anemonefish or clownfish which shelter from predators within the anemone and are immune to the animal’s stings.  Some species of sea anemones are believed to be able to survive for 100 years or more.

Could there possibly be an underwater scene more appealing than a cluster of anemones with their resident clownfish darting in and out of the tentacles?  These fish have a mucus layer on their skin rendering the venom harmless to them.  Another creature that has a symbiotic relationship with some anemones is the hermit crab which by allowing the anemones to hitch a ride on its back may be the crab’s way of gaining protection from its predators.

 Anemones have a central mouth surrounded by tentacles that are equipped with nematocysts – stinging cells that paralyse and entangle small marine creatures.  They are related to corals and sea fans and obtain their food by filter feeding.  They spend their lives attached to rocks or coral where they wait for passing fish to become trapped in their venom-filled tentacles.  Only a slight touch is sufficient for the tentacles to be triggered.

Anemones can be as small as 1.25cm or as large as 1.8m across and come in a vast range of colours.

Symptoms 
Symptoms occur immediately on contact and can vary from a slight prickly sensation to quite severe burning pain.  The sensation will increase over the next few minutes and over a short period the symptoms may extend up the limb.  The pain generally eases over a few hours but an ache or sometimes an itch could last for weeks.  The area of the sting will become red and swollen and blisters could develop.  Ulceration of the tissue could result in severe cases.  In this case, secondary infection of the ulceration is possible.  The victim may suffer from fever, chills, thirst, nausea and vomiting, abdominal cramps, headache and confusion.  In very serious cases the victim may become pale, cold and clammy which is an indication of shock.

First aid
Douse the area with vinegar to neutralise the nematocysts but this will not ease the pain.  Ice packs, local anaesthetic sprays, ointments and creams may be effective for this.  In case of respiratory distress enlist medical assistance.  Resuscitation may be necessary.

Crown of Thorns starfish
The Crown of Thorns starfish is a large starfish that can grow to more than one metre in diameter.  It can have up to 21 arms and the upper surface of its body is covered in long venomous spines that are up to six centimetres long.  It is a fast-moving starfish, able to move up to 20m in an hour.

This starfish spawns from December to April when the temperature of the water is around 28°C.  It releases eggs and sperm into the water through pores on the top of the central disc.  After the eggs are fertilised they develop into larvae which will spend from two to four weeks drifting in ocean currents.  When these juveniles are about one to two millimetres across they settle on the reef where they live amongst rocks and rubble but are virtually invisible until they are about six months old.  Adults generally have between 14 and 18 arms as they shed them when stressed or lose them to predators but, in time, they are able to regrow them.

The Crown of Thorns Starfish is notorious for its destructive actions on the Great Barrier Reef where it has decimated reefs at an approximated rate of five kilometres a month.  Organised eradication programs are regularly instigated particularly in tourist areas with some animals removed from the reef, others are given a lethal injection. 

They seem to prefer shallow water in sheltered lagoons but when found on exposed reefs they tend to be in deeper water away from wave action.   The short, very sharp spines can pierce skin easily.  Venom is injected when the spine pierces the victim’s skin.  Even dead animals that have been washed up on the beach can inflict a nasty sting.

Symptoms
Pain is generally instantaneous and severe.  This can last for a few hours before easing.  Swelling, redness, heat and numbness as well as loss of movement may occur.  Lymph glands may become tender and swollen.  Spines may break off in the wound and if not removed completely could cause the symptoms to continue for weeks or months.  As the original symptoms diminish, severe itching may develop.

Severe envenomations and those where spines have not been totally removed could result in vomiting which could start after about an hour.  This could last for days with nausea lasting much longer.  Contact with the slime covering this animal can result in a contact dermatitis.

The animal is believed to be poisonous if eaten.

First aid
Loose spines should be removed but any that are firmly in place should be left until medical attention arrives.  If not pulled straight out, they will break off leaving the tip still embedded.  The limb should be immobilised and the victim should rest.

The venom is not heat stable.  Pain may be reduced by immersing the wound in hot water but test it to make sure the patient won’t be burnt.  Around 50°C is advised.  Iced water may also relieve the pain.

Under no circumstances use the old treatment of placing the animal on the wound allowing the suction pads on the arms to clamp onto the injured area.  This does not work and in all probability would cause further injury.

Sea Urchins
Sea Urchins are solitary animals but may live in loose groups.  They are scavengers that feed on algae and animal remains.  They move on hydraulic tube feet in much the same way as Sea Stars.  They tend to be black but sometimes occur in a range of colours such as brown, white and purple.  It is believed that urchins could be crucial in controlling seaweed such as kelp, on reefs.  In areas where they have disappeared, seaweeds have generally increased in numbers and in some cases they have replaced coral reefs with seaweed forests.

Urchins hide in crevices during the day coming out at night to feed.  They are from the echinoid family which feed in two main ways.  Some graze on macroalgae like kelp.  Others wait for particles to settle on their body surfaces or by directly ingesting sediment.

There are several different species.  Spines of the Diadematidae are extremely sharp and 20-25cm long.  This species displays purple and white bands - juvenile colouring - until it grows larger at which time it takes on its typical black appearance.  Another species, the Toxopneusidae, have short thick spines which poke through flower-like appendages. 

The impenetrable barrier offered by the spines make them safe from most predators but there are several fish that do prey on them, including large trigger fish and wrasses. 

The spines which are brittle pierce on contact then tend to break off in the tissues.  The imbedded spines can become absorbed by the tissues within only a few days but alternatively they could become encrusted and calcify.  They can remain for many months later emerging at sites far from the original wound. There may be a venom gland on the tip of the sharp spines. 

Sea urchins are a popular food item in some European, Pacific and Asian cultures.  Some sea urchins are poisonous so they should all be treated carefully.  The roe of these animals is considered a delicacy in the Orient and the Pacific.  Some countries have sea urchin fisheries with the roe considered a delicacy and aphrodisiac but poisoning can occur, probably when the ovaries rather than the testes are eaten.

Urchins have symbiotic relationships with Polychaete worms and fish (e.g. cling fish) which seek refuge amongst the spines and probably clean the surfaces between the spines.

Symptoms
Eating the creature can cause diarrhoea, nausea, vomiting and migraine-like symptoms.

Envenomation symptoms include severe pain immediately after penetration of spines which will last between 30 minutes and four hours.  Spines usually break off when removal is attempted.  Numbness can be expected around the site with swelling and inflammation occurring.  The wound will turn black and this may be mistaken for a piece of spine in the wound.  This will last for many days.  With no foreign body in the wound or infection resulting from the penetration, the lesion should heal within one to two weeks.

First aid
The limb should be immobilised and it is not recommended to try to remove the spines unless they can be removed easily without breaking them.  Leave that until medical assistance arrives, if at all possible.  The suggested recommendation is to bathe the wound in methylated spirits and hot water at 50°C.

Respiratory distress may occur in severe cases.  Mouth-to-mouth or artificial respiration may be necessary if the victim has breathing difficulties or begins turning blue.  If this does not correct the colour or if there is no detectable pulse or heart beat, external cardiac massage may be necessary.  Seek medical attention.

Prevention
Wear hard shoes when walking on the reef and while the spines will penetrate gloves there may still be some value in wearing them.

Fire Coral
Fire corals look a lot like real coral but are technically not corals.  They are, in fact, more closely related to jellyfish and stinging anemones.  Fire corals generally have brightly coloured yellow-green and brown skeletal covering and are widely distributed throughout tropical and subtropical waters.  They appear in small brush-like growths on rocks and coral and divers often mistake it for seaweed.  Accidental contact is common which can result in intense pain that can last from two days to two weeks.  Fire corals have very small nematocysts containing tentacles protruding from many surface pores.  Fire coral’s external skeleton is very sharp and can scrape bare skin.

There are several common forms of fire coral including branching, plate and encrusting.  Branching has a calcerious structure which branches off to finger-like tips.  Plate has a shape similar to the smaller lettuce corals.  Encrusting fire corals form on the calcerious structure of other coral or gorgonian structures.

Symptoms
A burning sensation or a stinging pain develops within five to 30 minutes following skin contact with fire corals.  A red rash with raised areas appears and itching develops.  Lymph gland swelling may occur over time. On rare occasions, nausea and vomiting have been reported.

First aid
Rinse with seawater.  Don’t use fresh water as it will increase the pain.  Apply vinegar and remove any tentacles with tweezers.  The limb should be immobilised as movement could cause the venom to spread.  Hydrocortisone cream should be applied two to three times daily as needed for itching.   Discontinue use of the cream immediately any signs of infection appear.

If the victim suffers shortness of breath, swelling of the tongue, face or throat or other signs of an allergic reaction treat with antihistamines.  If there are no signs of allergic reaction, pain may be relieved with painkillers.

Medical treatment should be sought in severe cases.

Precautions
Don’t touch fire corals.  Divers often wear full wetsuits even in our warm waters due to the risk of accidentally brushing stinging animals, as that is one sure-fire way of ruining a dive or a holiday.

Hydroids
These fernlike animals live in colonies and generally have delicate fronds with rows of tiny polyps along each ‘branch’.  Attached to these branches are cup shaped feeding polyps with a central mouth surrounded by tentacles.

There are more than 3000 species of hydroids world wide.  They can look like seaweed but are, in fact, animals with plant-like habits.  They usually form extended colonies attached to rocks or plants.  Colours vary from white to brown/green to purple.   They appear totally harmless in their warm water habitats and are sometimes confused with the feather star.  Probably the best way to recognise the difference is by its habitat.  Hydroids often cling under ledges and in crevices. 

They can be handled with no injury at times but at other times can inflict painful stings.  The slightest brush against one can cause instant pain and in many cases a diver doesn’t realise what has caused the sting.

Stings can vary from mild to extreme pain which usually increases in intensity for the first ten minutes after the sting.  A red blotchy mark on bare skin is generally the first visible sign with weals appearing within 30 minutes and this rash may last for up to a week.  Peeling and ulceration of the skin sometimes occurs.

In rare cases symptoms may include abdominal pain with cramps, nausea and diarrhoea.  Other effects may be fever and chills; confusion and loss of consciousness.

First aid
Treatments include vinegar, calamine lotion, ice packs, alcohol (applied externally – not internally) and these should neutralise the sting.  Anaesthetic ointment is an effective pain reliever with steroid creams used for later itching.  It may take up to a month to heal.

Blue-ringed octopus

There are two species of blue-ringed octopus.  The larger (hapalochlaena lunulata) grows up to 20cm across its stretched tentacles while the smaller more common one (hapalochlaena maculosa) weighs a mere 28 grams.  They start life about the size of a pea, reach the size of a golf ball as an adult and have a life span of about two years.  Each animal can carry enough poison to kill 26 adults in minutes.

The Blue-ringed octopus is pale brown to yellow unless it feels threatened when the blue rings on its body ‘light up’.  It has a beak that can penetrate a wet-suit so while they may look cute they are definitely another ‘look but don’t touch’ creature.

These animals are found in shallow coral and rock pools of Southern Queensland, to Northern Tasmania and Western Australia.  They are not aggressive and if disturbed will flatten out the body in an attempt to hide and will change body colour to blend into the surrounding area.  They have a sack-like body and eight arms that are covered with suckers.  The Blue-ringed Octopus hunts during the day for invertebrates and wounded fish.

The female lays around 50 eggs in late Autumn.  The eggs are carried around under her arms until they hatch after three to six months.  The female then dies.  The young animals develop and mature rapidly.  They mate early the following autumn with the males then dying.  The female broods the eggs and the cycle begins again.

Symptoms
While its bite is apparently painless, the poison is a paralysing venom.  Paralysis is followed shortly after by death.  It should be noted however that injuries have only occurred when an octopus has been picked out of its pool and provoked or stepped on.  Although victims may have fixed dilated pupils they will have all their senses and be totally aware, but will be unable to respond.

Symptoms include nausea; initial hazy vision becomes blindness within seconds; loss of sense of touch, speech and the ability to swallow.  Within three minutes, paralysis sets in and the body goes into respiratory arrest.

First aid
There is no known antidote.  Pressure-immobilisation and prolonged artificial respiration is the only option here.  The only treatment is hours of heart massage and artificial respiration until all the poison has worked its way out of the victim’s system and if the artificial respiration has begun before marked cyanosis and hypotension has developed.  Mouth to mouth resuscitation can keep the victim alive as the poison will gradually wear off after 24 hours.  If this is successful, there are apparently no side effects.

Final words
While all the oceans of the world have creatures that can injure or even kill, we should not be deterred from exploring and enjoying them.  It only takes a little bit of common sense to ensure our safety and in the event of an injury you should now be in a position to be able to render first aid.

Remember at all times that we are in their habitat.  Look, enjoy and stay safe.