5
BEACH AND BEYOND
If you are predisposed to phobias about the deadly and dangerous animals of the deep, no doubt it’s the marine megafauna that feature in your nightmares. But wait, there’s so much more to be anxious about. Taken collectively, the smaller sea critters of reef and shore have a far greater impact on humans than sharks or rays. As usual, humans as a species pose more of a threat to all of these species than vice versa. Also as usual, the Anti-Tourist Board has been at work enlarging and elaborating the extent of the threat posed by box jellyfish, blue-ringed octopuses, stonefish and cone shells. Still, it’s quite true that these kinds of animals can and do cause an enormous amount of human pain and suffering, even if they do not take a high toll in terms of human deaths. Fortunately, sensationalist press notwithstanding, encounters with these dangerous animals are largely avoidable. None of these species seeks us out so let’s go in search of them within the absolute safety of this book.
HANDSOME IS AS HANDSOME DOES
Tulip cone, cloth-of-gold cone, cat cone, leopard cone, monk cone, glory of the seas cone: some cone shells have singularly enchanting names. Others are less attractive: flea cone, rat cone and spiteful cone. The names seem to offer a before and after parable of human relations with this animal. Many species of this genus are highly prized by shell collectors for their beauty and in some cases rarity. ‘Spiteful’ is perhaps the least of the negative epithets that might be uttered by any unwary person stung by one of the eighteen species of cone shells that are definitely dangerous to humans. According to the indefatigable Australian toxicologist Struan Sutherland, seven species top the list: geographer cone ( Conus geographus), glory of the seas ( Conus gloriamaris), feathered cone ( Conus omaria),striated cone ( Conus striatus), textile cone ( Conus textile), princely cone ( Conus aulicus) and tulip cone ( Conus tulipa). And, of these, it is the geographer cone that is implicated in the most human deaths. The other 280 or so species of cone shell have some venomous capacities so they all deserve cautious respect, but none are so distinguishably dangerous as the magnificent seven.
Yet even these seven are not major players in human fatalities. Worldwide the reported death toll is variable, but totals always number in the tens or dozens rather than the hundreds or thousands. On the other hand, there are much higher numbers of people who survive such stings, and many of them experience quite a lot of morbidity (ill health) and suffering. At the time of envenomation by a cone shell a person will usually feel sharp pain, which can range from mild to unbearable. Some stings leave no mark, others a whitened area with a bluish hue. Numbness and swelling are common. With serious stings, there is a range of distressing symptoms including sensory disturbance, severe itching, paralysis and brain swelling. Coma and cessation of breathing presage death unless skilled and sustained CPR is continued until the person can be attended by emergency medical personnel.
THE BIGGEST SHELL
Cone shells are marine gastropods: snails in lay language. And—as even preschoolers can observe—snails carry their home on their back. But the insatiable desire to collect the biggest shell, the prettiest shell, has led to a worldwide trade that threatens the survival of these gorgeous creatures. The collecting and buying of shells is nothing new; the European shell trade has been in existence for at least the last 500 years. A cone shell auctioned in Amsterdam in 1796 fetched a higher price than a Vermeer painting.
What seriously concerns many eminent scientists today, however, is the sheer scale of the trade (millions of animals are killed annually), the lack of regulation in most countries and the concurrent threats to cone shells from environmental destruction. After all, as for all of us, a snail’s true home is its habitat. For cone shells this is frequently mangroves (half of which have already been lost) and coral reefs (a quarter of which are seriously damaged). Both habitat types are suffering serious and sustained threats ranging from pollution, through predator species such as crown-of-thorns starfish, to global warming.
Grave fears for the loss of species, along with their potential for human benefit prompted Eric Chivian from the Harvard Medical School and two colleagues to publish a landmark letter in Science in October 2003, urging scientists to take these threats seriously and take action to help conserve cone shells.
SNAIL MEDICINE
Cone shell toxin has more than 100 different constituents, each with variable effects from paralysis to pain. Like those of many other marine invertebrates, cone shell toxins are biologically active agents that can potentially benefit humans. Some of the possibilities are antibiotic, antiviral, antifungal and antiinflammatory compounds. This represents a veritable pharmacopoeia, at least potentially.
This potential is being followed up by active research into the biological pathways of cone shell toxins that may end up providing far more effective analgesics for nerve pain in cases where opiates are inadequate or ineffective. This could provide great benefits for people who have some complications of diabetes, certain forms of cancer and AIDS—all of which can produce excruciating and virtually untreatable pain. Already there are stage-three clinical trials for a synthesised drug called Prialt, developed from cone shell research. Prialt is estimated to be up to 1000 times more effective than morphine, and without its addictive potential.
Research into cone shell toxins requires a supply of cone shells. Many of these are harvested from the wild, leading to some concern that this additional stress on an animal species that is already over-collected for the shell trade may well result in extinctions. One way around this is to farm live animals, which is the approach taken by research professor Jon-Paul Bingham. Bingham is an Australian who works from the Laboratory of Molecular Neuroscience at Clarkson University, Potsdam, New York. He is the author of many scientific papers, including the intriguingly titled ‘Cone shells, condoms and cod liver oil—The study of the milked venom from toxic carnivorous snails’. The introductory phrase sounds like something from the sleazier side of the sex trade, but of course it’s not. Apparently, unlubricated condoms are the perfect membrane for milking cone shells of their venom. Now that’s practising safe science!
BEYOND BLUE
It may sound like an urban myth, but it lacks the macabre ending and is in fact true. A friend of mine went for a walk down to her local swimming beach in Western Australia one summer and came across a group of tourists who—judging by the depth of their sunburn—were on holidays from Britain. They were gathered around a bucket peering in animated fascination, and gently poking the occupant of the bucket with a child’s spade. In the few inches of sloshing seawater was a small, sandy-coloured, seemingly innocuous little octopus. In fact, a very upset and angry little octopus. Such a tiny creature; it looked so lovely when mad, its thin, peacock-blue rings pulsing.
‘For pity sake don’t touch it!’ ‘They’re deadly!’ ‘Their sting is agonising!’ The Aussie onlookers—including my friend, who knew that the last claim was untrue—were well aware how implausible their warnings would sound. To non-local ears it could so easily and perilously seem like a classic tease. Anything less resembling deadly giant octopuses, squids and ancient mariner’s monsters would be hard to imagine. Fortunately for them, the group collectively conceded that discretion was the better part of valour, and declined to empirically ‘disprove’ such seemingly fallacious advice.
But what if they hadn’t? What if they had gone ahead and picked up the animal? Well, the blue-ringed octopus is definitely small: body size is usually from 4–6 centimetres and tentacles vary from 7–10 centimetres, thus the span of its tentacles is unlikely to be much bigger than 20 centimetres. However, it is absolutely true that they have venom capable of killing a human. In this case, size really does not matter because the blue-ringed octopus is considered the most venomous genus of octopus in the world. There are around ten species in the genus. Two of those found in Australian waters have been known to cause fatalities. At first, they appear to be named with the typical Australian linguistic reversal: the larger animal is called the lesser (sometimes southern) blue-ringed octopus ( Hapalochlaena maculosa). Its slightly smaller cousin, H. lunulata, is called the greater blue-ringed octopus. However, the ‘greater’ and ‘lesser’ refer to the size of the rings, not of the animals themselves.
Members of the blue-ringed octopus genus can live in water from 50 metres to extremely shallow shorelines, anywhere from the Sea of Japan south to Australia and across to Vanuatu, the Philippines and Sri Lanka. For example, H. maculosa is only found in southern Australia but occupies the whole vertical span of the continental waters. Hapalochlaena lunulata, on the other hand, has a broader distribution but does not live at such depths, being only found down to about 20 metres. Lunulata are often found in rock pools and tidal flats, areas also frequented by humans. It is not uncommon for them to take refuge in small containers both natural (shells empty of their original inhabitants) and artificial (tins, bottles, etc.). Given the widespread distribution of these species in the subtropical and temperate waters, and their potential toxicity, it’s surprising that relatively few people have actually died (two in Australia and one in Singapore over the last 50 years, although many more have been bitten, with variable consequences). Perhaps this is largely attributable to the fact that the species is singularly nonaggressive, and not likely to attack unless severely provoked—by being confined in a bucket and prodded, for instance. Also, despite their wide distribution they are considered to be relatively rare across that range.
Another factor reducing the risk is that blue-ringed octopus venom does not come from tentacle stingers nor is it injected. It comes from glands near the animal’s small beaked mouth, and flows in with its saliva when it bites, generally for predation (crabs are a favoured food)—and occasionally for protection. It’s not unheard of for people to be bitten under the water; those who are have some advantage as it may mean less venom actually enters the wound. Overall, however, a person would have to be extraordinarily unlucky to get randomly bitten: the majority of recorded bites occur when people pick up what seems like a pretty and harmless sea creature and put it on their outstretched arm or hand for a closer look.
So if one of the tourists had picked up that little blue creature and been bitten, what would the outcome have been? The blue-ringed octopus’s ‘poison of choice’ is tetrodotoxin, a neurotoxin that induces swift paralysis. This is the same toxin that is found in the flesh of toadfish and pufferfish. Blue-ringed octopus venom also contains hapalotoxin, although this is not considered much of a problem either for humans or crabs. Its chief role seems to be as a means of defence against fish that prey on the octopus. Around 7 milligrams of venom is a common yield for the average sized blue-ringed octopus, which is sufficient to paralyse ten adult humans. Unlike the stonefish or stingrays (whose venomous arsenals feature a different array of chemicals), blue-ringed octopus venom does not cause much pain if any. Even the physical pain of the bite may go unnoticed, especially with underwater encounters. In fairly short order, the bitten person would experience tingling and numbness of the face and neck. Muscle weakness, sight and speech disturbances follow. There is often difficulty breathing and occasionally vomiting. Finally, paralysis ensues, and this may last from four to twelve hours. Particularly vulnerable people—children, elderly or frail individuals—can die within half an hour, so swift first aid and urgent medical attention are essential.
MADONNA CEPHALOPOD
TOUCH NOT THE OCTOPUS
My ancestors’ clan motto in Gaelic is Na bean don chat gun làmhainn. It means ‘touch not the cat without a glove’. The same applies to blue-ringed octopuses, although people don’t have much call to worry about them in Scotland! (Not yet, anyway—see ‘Indicator species?’). However, the motto is apt and should be adapted to say ‘touch not the octopus at all!’ Sadly, however, the old story of ‘what can be bought and sold will be bought and sold’ applies even to this little creature. The trade in blue-ringed octopuses for aquariums is a stupid idea. Ask Dr Roy Caldwell, a researcher from California with a professional interest in cephalopods. Even with all his professional knowledge and skill he has very nearly been bitten by a captive blue-ringed octopus. He presents some compelling reasons for the home aquarium owner to leave blue-ringed octopuses where they belong—in their own environment. Primarily, this is because the species cannot sustain such large-scale capture simultaneous with major threats to its habitat. Even from the consumer’s point of view it doesn’t make much sense to buy (and re-buy and rebuy) an expensive little animal that keeps dying on you, unless it gets to kill you first. They are, after all, deadly. Why risk it?
A WORSE FATE
Blue-ringed octopuses, cone shells and stingrays are all possessed of a singular beauty. The best you can say of a stonefish, alas, is that it is unlikely to cause death if it stings you. The kicker is that you might want to die, as the pain of a stonefish sting is excessively excruciating. The effects are well known to traditional coastal dwellers and they are dramatically enacted in the corroborees of the Aboriginal people of some northern Australian groups. Practitioners of traditional medicine from northern Australia to coastal Africa have developed remedies to address the pain caused by marine stings from stonefish and stingrays, some of which are in current use. Their knowledge is also reflected in the precise clinical description of the effects of stonefish envenomation that shines through the dialect of this Australian Aboriginal man speaking more than 100 years ago:
Well might you wish to die, but current medical thinking is that it is extremely unlikely for a person to die from a stonefish sting. The cause of the few deaths that have occurred in the immediate days following stonefish envenomation is perhaps attributable to secondary infections, including tetanus.
DOCTRINE OF SIGNATURES
Those of a mediaeval mindset might take note that stonefish have thirteen venomous spines: an ominously obvious number for something so scary. The thing about stonefish, though, is that they are the ultimate practitioners of passive aggression. Researchers quite specifically believe that stonefish and their relatives evolved such a fearsome array of venoms together with a completely unobtrusive appearance in order to be lazy. They are marine couch potatoes, moving only when absolutely necessary, and firmly believe in eating home-delivered.
The stonefish came by its common name because it looks like, well, a stone: knobbly, often greeny-grey and covered in warty bits and algae. They are highly unlikely to win a beauty contest, that is if you ever get to see one. Stonefish are plentiful but highly camouflaged, and even those who are stung seldom see the administrator. Of the ten species in the stonefish family (Synanceiidae), two are most referred to in the medical literature: Synanceia horrida (did the namers mean its looks or its effects?) and Synanceia verrucosa—the reef stonefish. Verrucosa means warty. All these are somewhat mild monikers compared with the names bestowed on some of the scorpionfish, which are fairly close relatives of the stonefish, belonging together with them in the Order Scorpaenoidea. One genus is dauntingly titled Inimicus, and the common names include bearded ghoul, devil fish and demon stinger.
A complete ring-in is the bastard stonefish, which is not even remotely related. It is a common name sometimes bestowed on the non-venomous frogfish that belongs to a different Order of fish altogether.
INSIDE AND OUTSIDE THE BOX
Stingrays may have involuntarily hogged the headlines in recent years, but their dangerous aura is somewhat of a chimera. It pales into insignificance when compared with the danger posed by the see-through jellyfish that share their watery kingdom. All 9000 Cnidarian species are venomous. No other phylum (large group) in the animal kingdom matches them. The word Cnidia means ‘nettle’, which seems like a bit of an understatement when it comes to the group of animals that go by this name. Every one of them is a champion stinger, but one genus stands out as the premier problem for humans. The hands-down winners when it comes to venomous marine animals are the box jellyfish, sometimes called sea wasps. There are around twenty species of box jellyfish. And of these the single most dangerous species is Chironex fleckeri, which has earned itself the rare poetic common name of ‘fire medusa’. Some scientists believe that this relatively passive animal is, in fact, the most venomous species in the world, and without doubt the most venomous marine animal.
Death can occur within minutes of receiving a sting. The death-dealing mechanism is a structure called a nematocyst, a word often used synonymously with Cnida, the stinging capsules that distinguish these animals. (There are, in fact two other types of Cnida—spirocysts and ptychocysts—but nematocysts are the only ones capable of puncturing the skin.) The structures can also be found in some corals, sea anemones, hydroids and gorgonians, as well as jellyfish. One of the reasons C. fleckeri excel as venomous animals is because they possess several different types of nematocysts designed to puncture, hook or exude a substance that sticks to human skin. The various operations of C. fleckeri’ s nematocysts could genuinely be described as ‘overkill’. The scientific consensus is that the swiftness of death in fatal stinger episodes must be dependent on direct injection of venom to the blood vessels and hence into the bloodstream. Children are the most likely to die from jellyfish envenomation, although other factors that increase risk are a person’s thickness of skin, the size of the jellyfish and the number of nematocysts released.
For humans as a species it would be easy to take it personally, but of course these mechanisms for prey capture evolved quite independently of us. We are of no use to jellyfish as food, as we are not their prey. This is quite different to larger deadly carnivores such as crocodiles, lions, sharks and bears which can and do eat those they kill, given the chance. Anyone unlucky enough to be stung by a jellyfish serves no such function, but is simply collateral damage of the animals’ extremely efficient mechanisms for capturing their actual prey, which are small fish and crustaceans. Chironex fleckeri may be a passive hunter like the rest of its transparent and spineless relatives, most of whom rely on tides for transportation and bringing prey in range. However, because the species possesses extremely sophisticated eye structures, some scientists hypothesise that hunting may be an active process. Either way humans are not the target.
In other words, then, they won’t come looking for you. The best idea is to simply stay out of their way. The current distribution of stingers is generally accepted to be north of the Tropic of Capricorn, throughout the Indo-Pacific region (see ‘Indicator species?’ for news of potential change). Those who live or travel to these areas should take heed of stinger season, which pretty much follows the wet season, anywhere from October to May. Of course, jellyfish pay attention to environmental cues rather than calendar dates so these are approximate parameters. The closer to the equator the earlier they appear, as early as August along Australia’s north coast. Popular public beaches on the east coast of northern Australia are patrolled and protected in a number of ways, including netting. But that is hardly practical for the vast areas of coastline of Indo-Pacific countries. In this case, local knowledge is invaluable. As a general principle, however, certain spots are known to attract congregations of jellyfish, including creek and river mouths—any estuarine habitat is favoured for generally hanging about. These areas are also used for spawning in late summer. Stingers are less partial to surf, coral reefs and deep water, but this is not a guarantee of their absence in such conditions. Swimmers beware! If you simply must swim, then a stinger suit is de rigueur. Locals would undoubtedly do well to invest in one, but improvising is always an option to improve your odds (see ‘The peculiar powers of pantyhose’).
THE INTERNATIONAL CONSORTIUM FORJELLYFISH STINGS
The history of jellyfish stings has tangled tentacles of woe, confusion and pain. People were stung and died, and it was often unclear what had killed them. There was also a lot of taxonomic confusion about various jellyfish species among scientists. Knowledge of first aid was scanty, often misleading and myth-ridden. A few individuals worked hard and pioneered solid, reliable data about certain species but the general picture was not very clear. This all started to change in the 1980s when two Australians, Dr John Williamson and Dr Peter Fenner, began to work systematically, drawing together the existing expertise, sorting out the unreliable stories and building a robust central data bank. They co-founded the International Consortium for Jellyfish Stings in 1989. One of the first things that became evident was that although Australia is one of the world’s hotspots for jellyfish envenomation it is by no means the only place to have such problems. The consortium followed up data from around the world drawing their information from a wide variety of sources, including media, medical and surf lifesaving reports, as well as toxicological and marine scientists.
Best of all, from modest beginnings of research and publications originated by the Queensland Surf Lifesaving Club, Williamson and Fenner—together with Joseph Burnett and Jacquie Rifkin—have developed a comprehensive and peerless international medical and biological handbook entitled Venomous and Poisonous Marine Animals.
INDICATOR SPECIES?
PERSPECTIVE ON POISONS
Dr Peter Fenner, co-founder of the International Consortium for Jellyfish Stings, notes all known deaths from these marine animals, which gives a relative indication of their danger:
THE PECULIAR POWERS OF PANTYHOSE
Some men but almost no women mourned the passing of old-fashioned stockings. Some people, however, saw the potential value of the new artefact—pantyhose. Plenty of bush mechanics have used them to substitute for a broken fan belt. But Dr Jack Barnes, a Queensland radiologist, really knew how to think outside the box. He was responsible during the 1960s for Queensland surf lifesavers wandering around unselfconsciously with pantyhose on their legs, and also (with a strategic snip at the crotch) pulled over their heads and arms. Even such a thin barrier was enough to make it safe for the lifesavers to enter the water and net, looking for stingers at public beaches. When they found them, they closed the beach. These days, purpose-designed and more attractive stinger suits are commercially available, but the principle of protection remains the same.
Barnes, along with Ronald Southcott and Hugo Flecker, is one of the pioneering heroes of stinger research. He is memorialised in the scientific name of the jellyfish that cause Irukandji syndrome: Carukia barnesi. He earned it. Nobody knew what caused the so-called Irukandji syndrome before he lay for hours in shallow water, breathing by scuba, until an insubstantial and transparent animal swam across his field of vision. Having trapped a couple of the suspect jellyfish he proceeded to sting himself, his son (presumably an adult) and a surf lifesaving friend. Sure enough, all three manifested the symptoms of Irukandji after 30 minutes, and ended up in hospital in severe pain. So his name lives on. History does not record the thoughts of the anonymous friend, the son or the son’s mother. By all reports, Hugo Flecker was an equally excellent field naturalist, although not given to such extreme methods. His name is honoured in the scientific name of the scariest jellyfish of all— Chironex fleckeri.
There is no Damascus award for this chapter, although it could possibly be argued that brave Jack Barnes was a potential candidate for a Darwin Award! Nonetheless, the knowledge gained by him and his colleagues has made it far easier for humans to co-exist much more safely with these deadly marine animals.