Red Sea Shark Attacks - Paper!

The Mako- source.

So there.

My backlog is nearly cleared.

Have you read the post about Collier's demented dog like I suggested?
If not, please do - and then please refresh your memory by reading, in chronological order, this and this post, and links, about those 2010 Shark attacks in the Red Sea.

And now, read this.

Well what can I say.

In general terms, it's probably the worst anti Shark feeding piece of pseudo-scientific rubbish I've read, ever. Considering the caliber of three first authors, this is hardly surprising - but it's a real shame to witness that they've managed to rope in Vincent, a generally smart guy who happens to make a living by taking customers diving with OWTs in baited conditions and regularly hand feeds large predatory Sharks!

Buddy - what the fuck?

But by all means, let's look at that shit.

There is actually one aspect I do like, and that is the evidence collection.
We now dispose of a good time line, good descriptions of the attacks and the injuries, have a good overview of the locality and of possible (albeit not always plausible, see below) factors contributing to the attacks and dispose of credible evidence linking an individual Mako and an individual OWT to the first two pairs of attacks.
But having said that - why does the paper assert that victim 2 was bitten in the buttock when the description of the attack states nothing of the kind? And where, please, is the evidence that the perpetrator of attack 5 is an OWT, let alone the same OWT as in 1 and 2?

And the interpretation?

Generally speaking, nothing I read leads me to differ from what I speculated back then, so no need to elaborate: agree about the contribution of the unique topography and the elevated numbers of water users, and that those were predatory events = attacks; skeptical about the Sheep and the Fish feeding; strongly dispute that the elevated temperature was causing a "need to feed" in the homeothermic Mako - rather the exact contrary! Or not?

But I notice that both the Mako and especially the OWT look emaciated which may be lending some creed to the argument about the overfishing of prey - but then, should the Sheep not have provided sufficient nourishment? Or may those Sharks have been sick?

And I'm still baffled by the fact that both Sharks were not coastal but epipelagic, and that they and at least one more OWT had quasi simultaneously found their way into the Gulf of Aqaba, well north of their usual reported range! Were they following a vessel or more likely, following prey that had been displaced north due to the heat wave?

Leaves Collier's demented dog.

Those folks continue to assert that an OWT that was being fed Fish by divers was thus conditioned to go and eat not divers but snorkelers. And that it bit them in the hands and in the ass because it had been hand fed, and the bait was being kept in a fanny pack. Like Collier's demented family dog!

What a load of crap!

This is what really happened.

Two, possibly three (additional Carcharhinid in attack 4) or even four (Carcharhinid in attack 5) Sharks attacked snorkelers and swimmers = people that emit noise/vibrations and are thus routinely the targets of Shark strikes. All Sharks and not only the hand-fed one struck the extremities (both legs and arms) because the principal vibrations originated there and because the victims used them to fend off the attacks.  The buttocks of victims 1 and 5 were never primary targets - instead, the injuries to the buttocks happened as the Sharks bit the victims in the upper legs and torso.

That simple - even an idiot like me can see it.

Any other interpretation is nothing but unsubstantiated anti-feeding propaganda, totally speculative pseudo-scientific horse shit. After literally thousands upon thousands of hand feeds of numerous species, we observe absolutely nothing of the kind those folks assert and on the contrary, are actually astonished at the continued shyness of the very same animals in un-baited conditions - and this corresponds to what everybody else in the industry is witnessing as well. Again: with the possible exception of SA, there is no geographical correlation between baited Shark dives and Shark strikes! Think Florida, California, WA, Reunion, Recife etc etc - there is no Shark feeding at any of those locations!

Like I said, not surprised,
When it comes to Levine and Collier under the academic leadership of Dr. Hopalot, it just reinforces my contempt for those people and their fake research institute. As per the link above, Collier is somebody who knows something about something and now has taken it upon himself to bloviate about Shark-related topics he hasn't gotten the faintest clue about. Ritter and Levine, barf - but considering that they regularly sell and partake in provisioned Shark dives, this moronic filth is just the pinnacle of hypocrisy.
Fouda was likely their host in Egypt and likely doesn't know better. Special H/T to Jennifer V. Schmidt and to all the other reviewers for their glaring failure in discerning the egregious faults of this stupidity. And finally, congratulations to Burgess, normally an anti hand feeding advocate, for not having partaken in this fiasco - likely more out of distaste for the individuals, but well done none-the less!

And Vincent.

Stop being a sucker - that affiliation will end up biting you in the ass big time!
Pun intended!

Oh and...  oceanic whitetip shark, Carcharinus longimanus (first paragraph). Really. If that doesn't say it all...
  

Undercurrent on Shark Feeding!

Yes we feed Sharks - Terry-fic pic by Terry Goss!

Gotta hand it to the folks at Undercurrent.
Starting with the idiotic title, they have managed to post the by far most preposterous piece of utterly stupid anti Shark feeding shit published by a dive magazine, ever.

WTF has happened?
What has possessed Ms Richardson to provide a platform for the ramblings of the anti industry zealots instead of trying to remain impartial like in the past? Tell you what happened: she clearly doesn't have the slightest clue about Shark behavior (poor innocent Cristina's Caribbean Reefs are not solitary but gregarious) or the Shark diving industry and its protocols, and is obviously increasingly believing and parroting what the clowns she is interviewing are feeding her.

Case in point, Ralph Collier.
No Vanessa, Ralph is neither a researcher, nor a scientist.
He is the prototype of what the Swiss call a Sesselfurzer, as in "someone who farts from a couch", very much reminding me of the Shark-hating voyeuristic parasite. His claim to fame is to head his Shark Research Committee (are there any other members?) whose only research consists in recording GW attacks on the Pacific coast of the US and publishing the statistics in a series of forgettable amateur publications. Like Ritter with whom he shares an affiliation, or whatever, to the SRI and the GSAF, he is the ultimate Shark pornographer who professes to be furthering Shark conservation but then ultimately reduces Sharks and their life history to one single aspect, that of Shark/human interactions, meaning Shark attacks.
Having been elevated to rank of "Shark expert" by the misguided invitation of the Egyptian authorities, he is now obviously basking in the limelight and being invited to run his mouth on topics about which he obviously doesn't have the slightest shred of knowledge, let alone expert competence.

What Collier spouts is not new.
It's basically a textual rehash of his interview on the atrocious Red Sea Jaws where he asserts that feeding Sharks will lead to attacks on innocent bystanders. The "proof": one single video showing divers hand feeding one single OWT with Fish stored in a fanny pack - which according to Collier has led that Shark to subsequently attack the hands and buttocks of two victims, leading the great researching scientist to derive a general rule pertaining to all Sharks in the Red Sea!
Howz that for taking intellectual and methodical shortcuts!

So we're looking at a shark habituated to human beings for getting food, and humans had taught the shark where the food was. And this occurred frequently in the Red Sea. With overfishing in the area, sharks have to come up to the reef area to feed, and now associate food with the human form. It's very much like training your family dog. When it sees your hand, it sits up to get a bite of that treat.

Right!
That's EXACTLY what trained family dogs do: they sit up whenever they see a hand (notabene, a hand that does not hold any food!), meaning all the time, and when hungry, they run out of the house and randomly bite the hands (and very possibly even the ass!) of passers by!
Which obviously begs the question, does Collier own a completely crazy dog - or may he be simply pompously bloviating without the slightest knowledge about the behavior of either dogs or Sharks.
You be the judge of that.

The rule is simple.
To know about the specific behavior of an animal, you need to observe that animal when it is engaging in that specific behavior, and this over an extended period of time. If you unable to do so (and I betcha that Collier's personal experience with Sharks is limited to maybe a few cage dives with GWs at best), you need to talk to the people who do, or read what they publish on the subject.
The people who feed Sharks and who observe Sharks that are being fed are some divers, several Shark diving operators and a handful of Shark researchers - and thousands upon thousands of fishermen and spear fishermen!

Surprised about the latter?
Fishermen do not only feed Sharks by presenting them baited hooks; many of them attract and often end up feeding Sharks when they drag in struggling fish and when they subsequently clean their catch and throw the scraps into the ocean. Spear fishermen are notorious for attracting, and even conditioning Sharks when they shoot fish and often find themselves embroiled in a competitive struggle over their prey. These people number in the hundreds of thousands and if anybody should be examined for possibly causing an increase of Shark attacks on the public, it should be them - not the few dozen operators conducting baited Shark dives!

But I'm not here to deflect and obfuscate.
I'm certainly not about to give you the spiel about how we, the Shark diving operators educate the public and contribute to Shark conservation, as it got nothing to do with the issue at hand. The issue at hand is whether divers feeding Sharks leads to an increase of attacks on people who do not partake in those events, like Collier asserts.
That is a testable hypothesis.

The first of the possible tests is simple.
A. Are there more Shark attacks on the public at or around Shark feeding sites compared to similar control sites.

Let me start with a pathetically trivial statement.
In order for there to be a Shark attack, a person and a Shark will have to be in the same place at the same time. Thus the incidence of attacks will inevitably depend on the following variables: the number of Sharks and the number of people present in a determined location; and also, the activity and behavior those people and the Sharks are engaging in.

With that in mind and considering that feeding Sharks will aggregate some species, one would indeed expect an increase in Shark attacks in the vicinity of Shark feeding sites - but when one analyzes the details, it is not quite that unequivocal.
In 12 years of feeding Sharks here in Fiji, we have witnessed

• a staggering increase in the number of Bull Sharks that roam wide ranges but regularly visit Shark Reef once they have discovered that it's a good place;
• a negligible increase in the number of the much more resident Greys, Whitetips and Blacktips, a species that does not roam and is thus not likely to be attracted from locations afar;
• but then, a decrease in the number of intermediate Sharks like the Silvertips, Lemons and Nurses, and possibly even Tigers;
• and with the exception of one single fly-by by a spooked Great Hammerhead, zero sightings of any other species, this despite of the fact that we regularly introduce 2-300 kilos of yummy bloody bait and despite being situated on the fringes of 300m deep Beqa Channel and of Beqa Lagoon that are all being prowled by a plethora of other Sharks like Zebras and Hammerheads but also pelagics like OWTs, Silkies and Duskies.

And what about Shark attacks?
There are only two Shark feeding operations in the country, Beqa Adventure Divers and the guys down the road, and we both conduct our Shark dives on the southern coast of Viti Levu facing Beqa Lagoon. Documented Shark attacks in the vicinity: a big fat zero, ever.
The few documented Shark attacks have happened in Taveuni where Tigers Sharks prowl the coast of the current-swept Somosomo Straights; in the mouth of the Sigatoka River where surfers insist on frolicking on a break despite of murky water and the occurrence of large Bulls and Tigers; and in various locations where spear fishermen have defended their catch, often at night.

Anybody wanting to venture a guess about the results from elsewhere?
More importantly, would any of the bloviating Shark attack experts please care to comb his collection of data in order to prove or disprove a causal connection? Maybe for once act like what they purport to be, forgo their idiotic ad hoc speculation and engage in the onerous task of following the scientific method instead?

B. What about the risk of Sharks biting people during Shark dives?

Let's go back to the above trivial statement and variables.
When it comes to baited Shark diving, the obvious, and equally pathetically trivial rule is this.

• the more Sharks are present, the higher the risk of a Shark bite
• the more divers are present, the higher the risk of a Shark bite
• the more dives are being conducted, the higher the risk of a Shark bite
• the closer the divers and the Sharks interact, and the more frequently those interactions occur, the higher the risk of a Shark bite

So, yes, unequivocally, Shark diving increases the risk of a Shark biting a person!
And the question of baiting versus non baiting? Yes, of course baiting increases the risk, as it draws in more Sharks and leads to closer interactions!
Duh!

The consequences? Please re-read this.
Some divers are happy to experience Sharks when and where they occur naturally. Others wish to predictably experience other species that are highly skittish and/or do not aggregate naturally and thus need to be attracted with bait. Assuming that baiting does not harm the animals, and so far, nothing indicates it does, it's not a matter of prohibiting baited Shark dives, it's a matter of ensuring a maximum of safety by adopting the best possible safety protocols!
Is there a residual risk - yes of course there is, especially for us in the front line!

But what about the motivation for those bites?
Please re-read this. It is, to the best of my knowledge, what we know about why Sharks bite people - and please correct me if you think I'm wrong.

With that in mind, I assert that nearly all of those bites are not predatory in nature.
Contrary to the plethora of bloviating Sesselfurzer, I look back on nearly 40 years of diving and on thousands of Shark dives, most of which in baited conditions. In all those dives with dozens of different species in different situations world wide, I have never been in a situation where I had the impression that a Shark was sizing me up as potential food, not one single time - and incidentally, everybody in the industry I have talked with shares the exact same observations.

I have however been subjected to multiple threat displays, this by Grey Reefs exhibiting agonistic hunch displays, by Silvertips becoming stiff and jerky and more recently, by large dominant Bull Sharks gulping and ramming me with their snout.

I have also witnessed several Shark strikes.
All but two were by Sharks biting the people directly handling the bait. All of them were characterized by one or more of these factors: competitive, frenzy-like situation; bad visibility; lack of concentration/distraction of the feeder; feeder being bitten in his left hand which was holding more bait; non-dominant, sub-adult animal barging in.
The two remaining strikes were retaliatory bites by Silvertips on people denying them access to bait, very much like the famous incident where a Silvertip bit Dinah Halstead in PNG.

Consequently, our procedures include the following

• all divers wear dark full body wetsuits and especially, dark gloves as pasty white hands sticking out of dark wetsuits may be mistaken for bait, especially in low visibility
• we maintain a clear separation between the customers and the Sharks
• the feeders wear chain mail gloves to minimize the effects of accidental bites
• we hand feed in order to always control the bait and to be able to withhold food once we deem that the animals are starting to behave competitively. In situations that become too tense, we temporarily interrupt our routine, retreat and wait for the animals to calm down again - which incidentally, they always do
• the feeder is flanked by bodyguards monitoring any dead angles and gets rotated out after ten minutes in order to prevent lapses in concentration
• there is only one feeder acting as the focal point for the animals, and he only ever holds a single piece of bait
• we do not feed in bad visibility of less than 10 meters and are particularly alert when the visibility drops, as we have observed that this is when the Sharks (who do not see through murky water any better than we do) tend to be particularly edgy as they have to rely on their other, less precise senses when approaching the feeder
• nobody but us approaches the bait bin, ever

Which brings me straight back to Richardson's stupidity.
It mentions two Shark attacks, that on Groh and that on Jimmy.

Jimmy was apparently bitten by a Caribbean Reef, a competitive, edgy and strictly piscivorous species, whilst handling bait in murky conditions. These to me are perfect preconditions for a mistake by the animal.

Groh was apparently positioned right next to the bait cage, meaning that the Bull Shark that bit him may have been engaging in behavior aimed at deterring a perceived competitor.
Furthermore, once the Shark destroyed the bait container and a lot of sand was kicked up in the process, it was trying to navigate in very reduced visibility and water saturated with fish juices, thus losing its sense of orientation and possibly mistakenly biting the first solid object it came across, i.e. Groh's leg. Was it really exactly so - dunno but it is certainly plausible.

And the Ritter attack?
The interpretation of what triggered it (= a stupid guy doing stupid things with macro predatory Sharks) keeps changing but to me, it's rather irrelevant anyway: this is clearly a predatory attack where the animal first tested and then devoured Ritter's calf.
Accident my ass!

C. Last query: are Sharks that are being fed by divers (and what about those that are being fed by fishermen and spearos?) more prone to bite people than unfed Sharks.

This is what Collier is asserting and Richardson is parroting - and of course what is being really asserted, is that fed Sharks will not engage in just any attack, but that they will be conditioned to perpetrate predatory attacks on humans.
This is of course a tricky one to document - notabene one way or the other!

There is of course no such thing as a generic "Shark" engaging in generic "Shark behavior".
Instead, Sharks are very different behaviorally both when it comes to species but to complicate matters, even when it comes to sex and age within the same species, all the way to pronounced individual character traits that can be shaped by individual experiences.
Also, the behavior of a species can be very different in different locations or at different times of the day, etc.

But having said that, I can share the following.
Our flagship species, i.e. the Bull Sharks that frequent Shark Reef have been fed for the past 12 years and are undoubtedly one of the most conditioned population of predatory Sharks on the planet.

Bull Sharks are very timid and hardly ever approach divers.
But we want our customers to experience them, and this is the reason why we resort to luring them in with bait, and to reward them whenever they approach one of our feeders in the way we like, i.e. from the left and slowly.
This is called training by positive reinforcement and I can assure you that contrary to all the pledges to the contrary that are meant to appease the tree huggers, all Shark diving operators feed the Sharks when trying to attract species that are shy and in locations where those species do not aggregate naturally. Teasing only just does not work long-term as the animals are not being rewarded and will simply stop coming.

It is thus fair to state that by feeding our Bull Sharks, we are conditioning them to approach people and thus engage in behavior they would not normally display.
But here's the catch: we observe that unlike Collier's demented family dog, our Bull Sharks will not simply approach just anybody: instead, they will only approach determined people, and this mainly only when those people are proffering food!

Example?
Look no further than when we are training a new feeder. For weeks on end, he will be standing next to the bin brandishing his treats - and the Sharks will look him up but never take a single bite! Talk about an exercise in total and utter frustration!
Eventually, a single animal who is very likely not one of the old-timers but instead a newbie who doesn't yet know anybody else will take a first offering and be forever linked to this one particular feeder. Only over time, some of the other Sharks will deign to come in for a snack, however really only when they have no other choice because their favorite human happens to have a day off.
Incredible - and yet, it's totally true!

Or here's another example.
I've been diving the Fiji Shark Dive since 2003, first twice and now, up to five times weekly.
I never feed the Sharks. What I do, is to observe and film them as part of our ongoing long-term monitoring. Over a very long period of time and by proceeding in very small increments, I have been able to attain a status whereby the Sharks appear to tolerate and at times largely ignore my presence, allowing me to roam freely among them without any discernible effects on their behavior.
But when people other than me or Rusi venture in front, the Sharks will inevitably retreat - unless we accompany them, and even then, their behavior will be decidedly more diffident!

And lastly, we observe this.
We frequently dive Shark Reef for other reasons, be it in order to service our moorings or because we are monitoring its health and changes in the composition of its population of Fishes.
The Bulls live deeper in the channel and when we don't carry any bait, chances of seeing them are extremely slim and limited to occasional fly-bys by single individuals. We have even mimicked the exact dive profiles of our Shark dives, as a control, and thus without any bait - again with the exact same result that the Bulls were simply not interested.

So much for the assertion that fed Sharks will approach and attack people - and this after 12 years of conditioning them to the presence of divers!

Granted, this only applies to the specific Bull Sharks that frequent the SRMR.
But until somebody comes and proves that a specific individual Shark that has been fed has increasingly attacked people in un-baited conditions, nothing will ever convince me that what I'm experiencing in Fiji does not apply to all Sharks that are being fed by divers anywhere!

There you have it, that's my take - thanks for your patience in trying to follow my rant.
Still think that Collier is an expert on Shark attacks in the Red Sea?

And what about Undercurrent?
Looking forward to reading Part number two - and very much hoping that Ms Richardson will start talking about the real problem that is besieging Sharks, i.e the global fishery targeting their fins! Not that I believe she will after this total fiasco.
But then, as they say, hope springs eternal!

Big GWS off San Diego - or is it?

And I quote.

When you see a picture like this one... you have to be weary, at first, of a hoax - but an EXPERT says, this one is far from it...
And though you and I may not be able to tell how big this Shark is from the picture, (the token owner of a demented dog and lover of large omnivorous plantigrades) can...
"The shape of this fin is very very suggestive of an animal that's in the fifteen foot range".

Wow!

But watch for yourselves - the man is truly a monster of erudition!

Or maybe, not so much.

Turns out it was an April's fool hoax, and that somebody had crudely doctored a pic of a dolphin, fooling not only Collier but apparently, a number of his colleagues - which of course begs the question, who else disposes of zero academic credentials but continues to publicly proffer EXPERT pronouncements about Sharks?

Lemme guess - the pompous bloviating fireman? The unequaled SVS?

Anyway.

Remains the issue of whether one can truly estimate the size of a GWS from the shape of its fin, a revolutionary technique that would spare the scientific community plenty of headaches and thousands of dollars in complicated and unwieldy laser equipment. When put to the question by Martin who incidentally happens to be the very person that uncovered the hoax, Collier indignantly lectures,

Wow - again!

Let's see... from apex to apex, would that be 55% or thereabouts - and if so, does that make me an EXPERT as well? 

But I'm digressing as always. 

So now, it's the shape, plus the distance between the fins - what, in millimeters? 

Cuz for the life of me, and much like those other laser toting ignoramuses, I could never tell the actual distance from looking at the pic at the top! But I sure can notice the glaring absence of a terminal lobe on the presumed exposed tail (compare to here, here, here and here!) - and thus, I will bravely go out on a limb and publicly call BS on Collier's assertion that he was right because actually, this is the superimposition of the image of a real GWS!

But then again, considering the historical precedent, who am I to say!

Opinions please: a) unfairly maligned EXPERT or b) pompous Sesselfurzer instead?

Part Two: The BAD and the Ugly!

Yum yum!

And now, to the juicy part!

But first.
This is when somebody will inevitably start shouting, how dare you attack fellow conservationists and invoke global peace and harmony and-so-on and-so-forth.

So lemme state this loud & clear, I don’t hate anybody here.

What I however do hate is bullshit.
And in the spirit of qui tacet consentire videtur, I will always reserve the right to criticize situations I don’t agree with - and if they happen to be in the public domain, I will also feel perfectly entitled to do so publicly!
I also believe that like in science, progress in conservation is achieved via dialogue but also, via robust debate where opinions may get heated but where everybody who is legit accepts that those are just the rules of the game – and where those who do not are simply not scientists and conservationists but posers and bullshitters.

In brief, where I’m coming from is that whereas it is great that Shark conservation has become sizzling hot and is uniting many passionate voices around a great common cause, bullshit continues to be bullshit and shenanigans, shenanigans - and the great common cause is in no way an excuse for any of that.
And like in real life, people are sometimes simply incompatible and thus mutually exclusive.

If you don’t agree, stop reading now - HNY and have a great life!
Seriously, spare yourself the aggro because the following aint gonna be pretty – but if you cannot resist and end up being outraged, spare me the lessons in ethics and instead, debate the assertions!

If the meteoric rise and the astounding successes of Pew teach us one lesson, then it is that the correct way to save Sharks is to pursue their protection by pragmatic, science-based advocacy and by hard work and smart negotiations aimed at legislative changes.
The rest is just stupid fluff and hot air, and counter productive to boot. We are not the ones who enact Shark protection - and rest assured that the people who do have zero time, zero patience and zero respect for the vocal clamoring of the Shark whacks!

Again, Shark conservation is inextricably liked (q.e.d.) to political and economic considerations, and he who does not understand that is just a fool.
Shark fishermen don’t hate Sharks, they want to make a buck – and the authorities don’t subscribe to conservation because they have changed their perspective and suddenly love Sharks, they do so because they have been convinced of the (eminently economic) need for sustainability and in the case of Sharks, because they have learned about the importance of several (not all!) species in regulating the marine environment and thus, of their economical value all the way to generating millions in income from tourism.

Shark finning?
The finning bans are archaic and ineffective and thus not anymore worth pursuing in isolation. Yes finning is an ethical abomination and needs to be abolished – but what is killing the Sharks is Shark fishing and if you care to open your eyes, you will quickly discern that many of the major Shark fishing hubs are processing the whole animals as the meat is increasingly sought after by ever increasing populations starving for protein, and other products like leather, squalene and even the eggs are introduced into the wider economy.

The facts and numbers?
Science is in continuous flux and the data do indeed change – but until they do, the latest peer reviewed science remains the best approximation of the truth.
Thankfully, there are now plenty of resources where anybody can consult the latest insights and data, meaning that those who continue to operate with inflated statistics and outlandish assertions lack any excuses and credibility whatsoever. The facts are plenty horrible as it is – so let’s please stick to those and refrain from the usual stupid inflated hyperbole!

The industry?
If there has been one trend at this year’s DEMA, then it has been Shark conservation - and everybody in the dive industry is now claiming that he has always been deeply and passionately involved.
Great – if only they all did walk the talk!

Instead, the usual shenanigans have continued unabated.
Don’t get me wrong, I know that nothing is just black or white. Competition is continuously leading many Shark diving operators to ever up the ante, this also very much in order to satisfy the continuous requests for ever more adrenaline by their clients. There is also an insatiable demand for images featuring stunt work with Sharks.
I understand that these are businesses and that those folks are merely trying to make a buck – but I certainly do not subscribe to the notion that these developments are inevitable, the more since we at BAD are doing very well indeed by promoting a totally different kind of experience, do not enable Shark porn and have in fact continuously tightened our protocols as a result of the stupendous increase in large Sharks visiting Shark Reef.

But you can’t have it both ways.
Stunt work with Sharks and promoting gratuitous adrenaline thrills got nothing to do with Shark conservation, period!

And the much-invoked Demystifying and Changing Perceptions about these Misunderstood animals?
Indeed - respectable Shark diving operations do that daily, and this without having to resort to those stupidities, and so do respectable Shark media!

Think about how the same was achieved with the terrestrial top predators: certainly not by showcasing scantily clad death-defying bimbettes perambulating in the savannahs and the Sundarbans and also not by turning alpha predators into pets by allowing tourists to physically interact with them, let alone ride them!

Changing perceptions by attempting to “prove” that we’re not on the menu of Sharks actually perpetuates the myth by reducing the animals’ fascinating and complex life history to one element only, that of shark-human interactions where some of the large species actually do devour people – which is perfectly normal and merely illustrates that they are the opportunistic top predators they just happen to be!

Nobody in his right mind asserts that Lions and Tigers are harmless – but most of us have learned to respect and love them for what they are, beautiful, charismatic and awe inspiring essential elements of their natural habitats, and very much endangered.
Think BBC documentary: that’s how you do it – and yes, the rest is just moronic BS!

Anyway, I’m digressing – here’s the list.

• Least credible Shark Conservation Org: Shark Research Institute
  
  Founded in the early nineties and once rightfully considered to be the visionaries and trailblazers in Shark conservation, this org has simply ceased to evolve and is now quite obviously well past its sell-by date.
  A motley grouping of baby boomers whose claim to fame, if any, lays way back somewhere in the distant past, they doggedly cling on to outdated concepts, data and strategies and achieve nothing substantive in the process. This year’s media by some of their featured members have been simply appalling, see below, to the point where the whole org is little more than a purveyor of clients for Amos’ pinnacle expeditions and has frankly become a major embarrassment to the cause - and being my usual polite self, I will certainly leave it at that!

• Most disappointing Shark Conservation Org: Shark Angels
  
  A great concept combining a promising initial triumvirate of passionate and good looking female Shark advocates, Shark Angels could have become the next big thing in Shark conservation.
  Well, after several years of waiting it turns out that it did not. Pretty girls posing with cardboard signs next to dead Tiger Sharks are just that, pretty - and the actual track record is that they have certifiably saved zero Sharks from the nets of the KZNSB or otherwise, not then and not after several years of pretty PSAs and obscure conservation work in SA. Now it appears that the epicenter has been moved to Canada and I remain equally unimpressed. Did I hear Toronto? Yes, maybe - but then again, maybe not so much!
  Up next? Canada. And the world... we shall see!

• Conservation Snake Oil of the Year: United Conservationists
  
  Wow. How could I be so blind!
  Like all strokes of genius, it’s so compellingly simple: humankind just needs to stage a media-based Revolution under the leadership of those visionary dreamers and doers - and the Planet will be saved! Because we are all inherently good deep down inside - and if you give us 50k, we'll even take you diving! We are the 99%!
  Send us your money and we will save the Sharks, Lemurs and Tigers! And we will end Ocean Acidification because once they see my movie, the uneducated masses in China, the US, Europe, India and Russia will rise and force global governments to agree on reducing emissions! Just like the Arab Spring – or whatever, just send us the money!
  Seriously!

• Least impressive Shark Conservation Achievement: California Shark Fin Ban
  
  As they say in German, The Better is the enemy of the Good.
  Talk about a missed opportunity! Nice – but given the impressive widespread good will, resources and star power, this is simply not good enough! Check out the legislation, corollary with exemptions and analysis: this is a (bad) licensing law that bans the possession of Shark fins (notabene, fins that are imported from Asia where they first get processed for consumption) and clearly unilaterally targets the principally Asian consumers of Shark fin soup in California.
  Is that really Shark conservation? Does closing down the Californian shark fin market really impact the global trade and really save Sharks, let alone combat Shark finning, one of the stated aims of the legislation? Convince me!
  
  Plus, there is this.
  The demise of California’s Blues and Makos is legendary - and yet with this law, the local commercial and game fishermen are still free to go and kill California’s Sharks, and anybody is still welcome to continue eating Shark steaks and to consume all other Shark products. And the outlawed fins of those Californian Sharks? Betcha that they get exported to Asia!
  Compare that to the excellent progress in Florida where more and more Sharks are being protected – still think this is an achievement to be proud of?
  But as I said, nice!

• Curiouser and Curiouser: Erik Brush (& Co!)
  
  "On the day that too many sharks have gone you will not know that a line has been crossed. It is only a while afterward that the sudden unleashing of methane hydrate into an already weakened atmosphere will show us our error. Then we will long for our predatory friends that could have regulated the food chain and kept the gas exchange of phytoplankton working for all life!" - Self Quote.
  
  New Age meets Shark conservation meets pseudoscience - and, meets the (obviously mad!) Hatter!
  Check out IMEC, Brush’s curious Facebook page and his curiouser personal website and tell me if I’m not right! And we've even got ourselves a new and mysterious Alliance!
  
  Anyway, all of this would just be harmless and actually, quite entertaining albeit in a bizarre way, were it not for the fact that the self professed marine biologist, Shark specialist and friend of Doctor Erich Ritter has managed to accumulate quite a loyal following (really? Are we witnessing the dumbing down of Hollywood?), among which some prominent representatives of the SRI who very much appear to endorse his pseudoscientific ramblings.
  Does Collier really think that Erik’s Shark math is very nice?
  Does the President of the SRI (doesn't R stand for Research?), apparently a German TV star and associate of Brush, really totally agree with Erik’s assertion that Sharks are the most critical factor besides human pollution to global warming and mass extinction?
  Whatever – right? But the cartoons are cute!

• Shark Pornographer of the Year: ABC4
  
  Well, no need to further post any evidence here.
  Andy is actually a nice personable guy, an accomplished cameraman and also brave to the point of being crazy - and thus highly sought after when it comes to filming stunts with large predatory Sharks. Several other cameramen do the same and although I hate the imagery they produce, I know that that’s what the market wants and respect them as professionals as I understand that they do what they do because competition in that field is fierce, jobs are scarce and they got bills to pay.
  What however riles me here is Andy's total hypocrisy of regularly partaking in Gurney’s despicable productions, see below, and then turning around and pretending to be a fervent Shark conservationist. Thing is, even if that were true, for every person conceivably heeding Andy’s self-professed conservation messaging, thousands are being certifiably influenced against Sharks by watching the images he produces.
  Can’t have it both ways buddy – either finally walk the talk, or take the $$$ and shut the F up!
  And the exact same applies to those Shark diving operators who continue to enable that shit - and no, I'm not about to post names lest I once again get accused of engaging in some food fight or the like: they know who they are and so do you!

• Shark Porn Production House of the Year: Gurney Productions
  
  Again, follow the link here.
  Discovery’s go-to people for those appalling Shark Week programs featuring idiotic scripts, idiotic experiments and idiotic anchors, they really transcend negative attributes. Absolute scum!

• Shark Porn Channel of the Year: Discovery Channel
  
  I’ve long stopped watching that shit that is Shark Week – but sometimes I catch a glimpse whilst zapping thru the wonderful selection of Fiji’s Sky Pacific and guess what, nothing whatsoever has changed. Not that they would care in the slightest - but I will continue to boycott Shark Week and BAD will continue to turn down those yearly requests for atrocious film shoots!

• Worst Shark Porn: How Sharks Hunt
  
  Featuring the chain wrapping of Emma, courtesy of ABC4 and Gurney - nothing to add to what I said there.

• Most embarrassing Shark Conservation Advocacy Stunts: Bikini Bimbettes and Warriorettes
  
  And I cite from a message by one of the Shark Greats – you would be amazed (and the bimbettes, totally ashamed!) if I told you her name!
  
  How I hate the latest bit of National Geographic Society shark porn!
  Absolutely ghastly that they have fallen so low, pandering to the lowest common denominator--sex and sharks. Not a scintilla of redeeming quality. I say this sight unseen as I refused to watch it after seeing the trailers.
  
  But that would be but one, albeit particularly pathetic example.
  Why some otherwise modern and emancipated women would agree to demean themselves by partaking in these embarrassing stupidities will forever remain a mystery to me – and undoubtedly, to the other 99.9% of intelligent modern and emancipated women who love Sharks but don’t engage in those shenanigans!
  
  Oh - did I hear Demystify and Changing Perceptions?
  By “proving” that Sharks don’t strike bikini bimbettes? Well guess what, they do, so sorry folks – and that makes them neither good nor bad, nor does that fact in any way diminish the validity of the assertion that we need to protect them!
  The swimwear stunts and experiments are moronic pseudo-conservation and pseudoscience that presumes that everybody out there watching is a retard – thing is, most people are not and will quickly identify them as what they really are, highly embarrassing self promoting publicity stunts!
  Tip o’ hat: Erich Ritter– and we all know how that one ended!

• Lifetime Achievement Award for Pseudoscience: Erich Ritter for Sharkitarianism
  
  Yes the above link is plenty sufficient!
  And after more than a decade of spouting those outlandish and I may add, very much self-debunked theories: still eagerly awaiting the first peer-reviewed paper on the subject!

• Most preposterous Assertions by Shark Expert: Ralph Collier
  
  George eat your heart out!
  Having managed to completely supplant him as this year’s undisputed token Sesselfurzer, Collier and his Shark farts have been nothing short of spectacular. From the epic dog analogy to having linked JAWS with the starvation of Grizzly Bears by means of the dreaded domino effect, the man is truly a cornucopia of moronic pseudoscience. Will he be able to further exceed this year’s stellar performance and grace us with more, forever unforgettable tidbits of hot perfumed air?

• Shark Conspiracy Whacknut of the Year: H E Sawyer
  
  Huzzah!
  We've finally got ourselves our very own, home-grown conspiracy – and shame on Wikipedia for not having posted it on the ominous list!
  So it turns out that not only are the numbers a conspiracy concocted by the scientific intelligentsia, but that all of us are (once again!) nothing but the puppets of Big Oil!
  
  Because, and I cite, shark conservation is actually a fig leaf for oil & energy corporations, through their ‘charitable trusts’ to ring fence large areas of international waters through MPAs, MCZs and ‘shark sanctuaries’ with the purpose of leasing it out to other oil & energy corporations, & using the money from that to fund the science that supports the policy of ring fencing large areas of international waters for ‘protecting sharks’ etc!
  
  Utter humbug? Far from it, here is the proof, black on white!
  Wow - makes Erik the Mad Hatter of Sharktivism look like a genius in comparison! If these are really the exhaust fumes of democracy, may I humbly suggest that this may indeed be this year’s ultimate Furz from the Sessel. May I further humbly suggest that the man urgently get himself a life and quite possibly, a diagnosis by a qualified psychiatrist, chop chop!
  
  As a reminder, here’s what the despicable cabal of evil has been doing in 2011 - unequivocally highly suspect!

Story here - check it out!

• Stupidest Shark Media: Guadalupe Mermaid
  
  Yes that would be the f@$%ing mermaid – and I’m still completely astounded by the sheer scope of the bullshit, hubris and mind-blowing stupidity!

• Irritating: Personality Cults
  
  Just one example among several.
  
  See, some of our founders made a little movie called Sharkwater. Soon NGOs started popping up and government policy started changing. All it took was information and a spark, and the world will never be the same.
  
  Have we got ourselves a case where the salesman is starting to believe his own marketing, with symptoms of incipient guru-esque megalomania?
  There is no doubt that Sharkwater hit a nerve and that it has done much for popularizing Shark conservation among the masses. But Rob is not the visionary trailblazer, Shark conservation did not start with Sharkwater and the recent spectacular successes are not at all attributable to that movie!
  
  Anyway, it is just one example and certainly not the most brazen one.
  The Heroes and heroines, warriors, whisperers, experts, specialists and whatnot are all legit if the moniker is being assigned by others - but when it is self promotion and really nothing more than branding, it becomes irritating.
  Does sharktivism really need its own version of the Kardashians and the associated frothy adulation and gossip? Maybe – but like in real life, I don’t like it one bit!

• Most Brazen Conservation Heist: Shark Research Institute
  
  Having nothing much to show for, the SRI is now mooching on other people’s hard work by insinuating that they were somehow responsible for all (!) of this year's Shark conservation achievements. From the SRI's Winter Newsletter - and I cite
  
  Thanks to you — our members — 2011 has been a very good year for sharks. Through SRI active participation, advocacy and legislative efforts we have achieved spectacular results. We still have work to do, but look at what has been accomplished this year alone!
  Give yourself a pat on the back!! Thanks to your support, 2011 has been a fantastic year for sharks. This year alone:
  * Honduras announced creation of 92,665-square mile shark sanctuary.
  * The Bahamas converted 243,244 square miles into a shark sanctuary.
  * The Marshall Islands, Guam and Palau created a region-wide 2 million square-mile shark sanctuary.
  * Chile banned shark finning in its water.
  * ICCAT agreed to reduce fishing of shortfin mako shark and porbeagle sharks (At least get your facts right! I thought you were there?)
  * The trade in shark fins, outlawed in Hawaii in 2010, was also prohibited in Guam, Oregon, Washington and California
  
  Certainly cleverly worded!
  I say, how cheap, sad and frankly revolting - simply unforgivable!

• Low Point of Academic Competition: Junior Controversy
  
  Got some time to waste?
  Read this and track back through the links. What you will discover is an ignominious smear campaign against Michael Domeier orchestrated by competing researchers. Dunno and don’t care much about what happened after it backfired, except for noticing that the Monterey Bay Aquarium has obviously not severed its contacts to the very much implicated Sal Jorgensen and Scot Anderson of TOPP.
  All very revealing and very disturbing!

• Stupidest Shark Conservation Memes and Slogans.
  
  Here, I did a quick brain storming session with some of my Shark friends.
  In no particular order: the Oxygen myth; No Fin No Shark No Future period (can anybody please tell me what that means?????); Fintastic; and last but not least, Fins Up!

And here endeth the list - happy I finally got it off my chest!

And, are you pissed off?
I sure hope so - the question being, at whom!
Comments welcome!

Shark-Human Interactions – Aggression?

One of the most frequent questions our customers ask is whether our Sharks are aggressive.

Our standard answer is to tell them that in our experience, they are not aggressive as in wanting to bite us but rather, that they may sometimes be assertive, meaning that some will try and barge in to get some food and that in doing so, they may display a degree of posturing.
Granted our definition may be threading a very fine line – but words are powerful and we want to steer the conservation away from the usual stereotypes and towards a more neutral mindset.

In behavioral terms, such assertiveness is called agonism, defined as any behavior related to fighting and competition,including fighting, threat, defense, flight, freezing, avoidance, and appeasement.

Very unfortunately, commercial Shark dives continue to slowly inch towards ever more close and personal encounters even with the biggest, most powerful and consequently most dangerous predatory Sharks.
In that regard, it becomes ever more important to adequately interpret the language of the animals and to adapt commercial diving procedures and one’s individual behavior accordingly, something that unfortunately appears to be missing both on the side of some operators and many clients alike.

Luckily for us, Sharks are far from being misunderstood and unpredictable and reading their state of mind is quite easy.
Equally luckily for us, they appear unendingly and uncomprehendingly tolerant and will generally gracefully overlook our breach of etiquette, meaning that people are likely to only get into trouble if they persist on displaying the most reckless, stupid and persistent of behaviors – which some individuals, being notoriously unpredictable, will undoubtedly manage to achieve!
Case in point!

The following paper is a useful compilation of the agonistic behaviors of several species of Sharks known in 2006. Yes it is long (!) but it’s an excellent reference for any Shark diver and thus, I believe, required reading. This is not the entire paper but merely excerpts that I have chosen for their immediate correlation to Shark diving.
More thoughts below.

A review of shark agonistic displays: comparison of display features and implications for shark-human interactions

Author: R. Aidan Martin
Disclaimer: Sharks are potentially dangerous animals. While the author offers his opinion on actions that may make encounters with sharks less dangerous, neither he nor Taylor & Francis accept any responsibility whatsoever for the safety of those who choose to interact with sharks, regardless of whether or not they follow the author's safety suggestions. Those who seek out interactions with sharks do so entirely at their own risk.

Abstract

Agonistic displays in 23 species of sharks of six families are described and illustrated.
These displays are reviewed in terms of ethological concepts and shark hydrodynamic models. Shark agonistic displays feature many common elements rendering them readily distinguishable from normal swimming and pseudodisplays caused by sharksucker irritation. Shark agonistic displays are most readily elicited by rapid, direct diver approach when food is absent and potential escape routes restricted. Such displays appear to be motivated by defence of self or the immediately surrounding space rather than defence of territory or resources. Costs and benefits of display versus attack in shark-shark and shark-diver contests are evaluated using payoff matrices and optimal strategies are identified. Shark-human interactions are modelled in terms of a system of nested critical approach distances. For divers faced with a displaying shark, responses which may decrease the likelihood of defensive attack are suggested. Recommendations for future work on shark agonistic behaviour are offered.
Introduction

Agonism is a class of behaviour that occurs in competitive contexts and is important to the social dynamics and evolutionary fitness in animals of many taxa (Hall and Halliday 1998).For example, individuals displaced or defeated in agonistic contests often disperse into adjacent habitats that are frequently suboptimal, thus reducing their feeding and reproductive success (Reese 1978). Agonistic behaviour is widespread among animals, including crustaceans, insects, spiders, mammals, birds, reptiles, amphibians, and fishes (see Bradbury and Vehrencamp 1998, for a recent review). Agonistic displays have been recorded in many teleost species, representing numerous families and orders (Fine et al. 1977; Colgan 1993; Guthrie and Muntz 1993; Helfman et al. 1997; Reebs 2001).

Many shark species exhibit a variety of social behaviours, yet agonistic displays have rarely been reported in this group (Bres 1993).
Shark agonistic displays are best known in the grey reef shark (Carcharhinus amblyrhynchos), which exhibits a distinctive, highly stereotyped ‘‘hunch display’’ (named for the characteristic raised snout-arched back posture, resembling a sustained shrug) in response to persistent crowding or oriented pursuit by divers or submersibles ( Johnson and Nelson 1973; Doak 1975; Stark and Anderson 1978; Nelson et al. 1986).
This display features four postural elements,
(1) a prominently raised snout,
(2) bilaterally (to_the same angle) depressed pectoral fins,
(3) arched back, and
(4) lateral flexure of the body, combined with two locomotory elements, (a) laterally exaggerated swimming, and (b) rolling and/or spiral looping ( Johnson and Nelson 1973).

The hunch display of the grey reef shark is a graded response, increasing in intensity with speed and directness of diver approach as well as degree of restriction of the shark’s escape route ( Johnson and Nelson 1973).
If a pursuing diver or submersible persists, the hunch display rapidly escalates to either a rapid withdrawal or a lightning-fast, open-mouthed slashing attack ( Johnson and Nelson 1973; Nelson et al. 1986) Thus, the hunch display of the grey reef shark is an accurate predictor of more intense defensive behaviours (Fellows and Murchison 1967).

Displays evolve from non-communicative source behaviours ritualised via a five-step process shaped by natural selection (Tinbergen 1952). Barlow (1974) proposed that the hunch display of the grey reef shark, like that of other predatory animals, was derived from movements associated with subjugating prey.

Accurate signalling of an animal’s motivation or state (‘‘display honesty’’) can be ensured by being costly, such as handicapping the signaller by diverting resources that would otherwise increase its fitness (Zahavi 1993).
However, accurate signalling must have benefits that exceed the costs for such behaviour patterns to be retained rather than eliminated through natural selection (Krebs and Davies 1993; Cuthill and Houston 1997). Costs and benefits of agonistic displays in the grey reef and other sharks have not been analysed.

The hunch display is most often elicited in situations where food is not present, such as close approach to a shark by an underwater photographer not using bait as a lure, and probably plays a role in normal social encounters among grey reef sharks ( Johnson and Nelson 1973; Nelson and Johnson 1980).
This species is widespread throughout the tropical Indo-Pacific region and, despite its modest size (most individuals are smaller than 1.5m long), is avoided by or actively displaces most sympatric shark species, including solitary heterospecifics larger than itself ( Johnson 1978; Compagno 1984). Myrberg (1991) suggested that distinctive fin markings in whaler and hammerhead sharks (Carcharhinidae and Sphyrnidae, respectively), especially on the relatively mobile pectoral and caudal fins, may serve as species recognition badges and/or accentuate signals, both social (intraspecific) and extrasocial (interspecific). The ventral apices of the grey reef shark’s pectoral fins are dusky and its caudal fin bears a distinct black rear margin (Last and Stevens 1994); in western Pacific and Indian Ocean representatives, the first dorsal fin features a conspicuous pale apex (Compagno 1984). Intriguingly, western Pacific and Indian Ocean grey reef sharks are more timid and less likely to display than those from French Polynesia or Micronesia (personal observation). Whether such regional differences in grey reef shark behaviour and markings are causally related is unknown.

The primary literature contains descriptions of agonistic displays similar in context and execution to that of the grey reef shark in several other shark species, including the bonnethead (Sphyrna tiburo), scalloped hammerhead (S. lewini), and blacktip shark (C. limbatus), but none as overt as that exhibited by the grey reef shark (Myrberg and Gruber 1974; Klimley 1985; Ritter and Godknecht 2000). Putative agonistic displays in several other shark species, including the Galapagos shark (C. galapagensis), Caribbean reef shark (C. perezi , white shark (Carcharodon carcharias), and shortfin mako (Isurus oxyrinchus), have been reported in the popular literature (Hobson 1964; Stoneman 1985; Compagno et al. 1989).

Confounding such anecdotal reports are recent studies showing that striped sharksuckers (Echineis naucrates) can induce behaviours that resemble agonistic displays in the blacktip shark, bull shark (Carcharhinus leucas), Caribbean reef shark (Video clip 4), and possibly other shark species (Ritter 2002; Brunnschweiler 2006).
Blurring the picture further are dissimilar shark behaviours reported under competitive contexts, including tail slapping (whip-like lashing of the tail at or near the surface, hittingor directing splashes toward a receiver), which has been reported in sandtigersharks (Carcharias taurus) and white sharks, and breaching (leaping completely from the.water) and repetitive aerial gaping (RAG: rhythmic, exaggerated opening and closing of the jaws above the surface, apparently as a displacement activity), which have been reported in white sharks (Compagno et al. 1989; Klimley et al. 1996; Strong 1996).

The present work reviews relevant theoretical background issues and putative shark agonistic displays from the literature, augmented and extended with opportunistic observations by the author and collected from experienced, credible divers.
What constitutes an agonistic display is defined and the challenge of differentiating displays from non-displays in sharks is discussed. Previously undescribed agonistic displays or new display elements in six species of sharks are described and illustrated. All known shark agonistic displays are compared and general patterns are identified. Relative costs and benefits of shark agonistic displays in interactions with other sharks and divers are evaluated using payoff matrices. Shark–diver interaction scenarios in which sharks are most likely to exhibit agonistic displays are reviewed. A hierarchy of critical approach distances for sharks is hypothesised and diver responses to an agonistically displaying shark that may reduce likelihood of escalation to full attack are suggested. Recommendations for future work on shark agonistic behaviour are offered.
Methods

Shark measurements and display elements used in this review are:

. Back arching – a sustained dorsal flexure of the back, so that it forms an inverted U, measured or estimated as the angle between the dorsal surface of the head and that of the pre-dorsal back (‘‘nape’’)
. Body length (BL) – estimated total length, from snout tip to upper caudal fin apex
. Body shivering – a quivering or rapid (faster than 5 Hz) shaking of the entire body, usually combined with a lateral display
. Body tilting or rolling – an exaggerated, sustained roll of the body around its longitudinal axis, up to plus/minus 45 degrees from vertical, either as a single action (tilt) or an oscillation (roll) (sensu Johnson and Nelson 1973; Klimley 1985; Ritter and Godknecht 2000)
. Charging – rapid (2 to 3þBL/s) approach toward a receiver, often terminated by veering away on a perpendicular course within a distance of 1–2BL
. Clasper flexion – rotation of a clasper (elasmobranch intromittant organ) anterolaterally, mimicking its erect state during copulation (sensu Myrberg and Gruber 1974)
. Corkscrewing – rapid burst swimming into a tight looping trajectory while rotating the longitudinal body axis through nearly 180 degrees (sensu Klimley 1985)
. Flank displaying – a sustained perpendicular bodily orientation of signaller’s body toward a receiver, displaying its lateral surface
. Follow–give way – an agonistic interaction in which one animal follows another, which deviates from its course, implying social precedence of the following individual (sensu Myrberg and Gruber 1974)
. Gill pouch billowing – a sustained conspicuous, spinnaker-like expansion of the branchial region; equivalent to ‘‘gill-puff’’ of Myrberg and Gruber (1974)
. Give way – an agonistic interaction in which one animal deviates from its course at the approach of another, implying social precedence of the undeviating individual (sensu Myrberg and Gruber 1974)
. Head shaking – rhythmic, exaggerated lateral shaking of the head, usually rapid (faster than 2 Hz) and through an arc of more than 30 degrees
. Jaw closing – a non-forceful bringing together the upper and lower jaws in an agonistic context (as compared to a bite, which is a forceful jaw closure during feeding)
. Jaw gaping – a slow, exaggerated opening of the jaws (30–90 degrees, measured or estimated as the angle formed at the mouth commissure), conspicuously wider than during ram ventilation and in an agonistic context, resembling a yawn
. Laterally exaggerated swimming – sustained , eel-like swimming motion
. Looping – swimming in a spiral loop (sensu Johnson and Nelson 1973)
. Open jawed tooth raking – a forceful strike with the upper jaw teeth causing injury to a receiver
. Palatoquadrate protrusion – forward extension of the upper jaw, causing it to separate from the cranium, and which may bare the upper dentition; categorized as present or not
. Pectoral fin angle (PFA) – is measured or estimated from a horizontal plane perpendicular to the body axis at the level of the chord formed by a straight-line from pectoral fin origin to pectoral free rear tip (which is often easier to discern than the pectoral insertion in free-swimming sharks); equivalent to the ‘‘dihedral angle’’ of Wilga and Lauder (2000)
. Pectoral fin depression – a sustained bilateral lowering of the pectoral fins from their usual position during swimming, quantified as pectoral fin angle
. Ramming with snout – a signaller using its rostrum to forcefully strike a receiver, often causing it to recoil or retreat; synonymous with ‘‘hit’’ of Myrberg and Gruber (1974)
. Rapid withdrawal – movement of a signaller away from a display receiver at _3BL/s.
. Rapid, tight pattern swimming – fast swimming marked by sudden and frequent changes in direction
. Reduced swimming efficiency – conspicuous reduction in forward locomotion, from almost normal swimming speed to nearly stationary in the water column, despite exaggerated swimming movements ( Johnson and Nelson 1973)
. Ritualistic jaw snapping – rhythmic (faster than 1 Hz), exaggerated opening and closing of the jaws, (30–90 degrees, measured or estimated as the angle formed at the mouth commissure)
. Snout elevation – a sustained raising of the snout from the resting position, measured or estimated as the angle between the dorsal surface of the rostrum and that of the epibranchial region (surface of the back above the gill slits) ( Johnson and Nelson 1973)
. Stand back – an agonistic interaction in which two oncoming animals deviate from their courses simultaneously, making it impossible to infer social precedence (sensu Compagno 2001)
. Stiff or jerky movement – a conspicuous reduction or loss of fluidity of body and fin movements during locomotion, probably due to an increase in tonus of associated muscles
. Swimming speed – is measured in BL/s
. Tail depression – a sustained vertical bending of the caudal peduncle, stiffly holding the causal fin downward, below the main body axis .
. Tail flexure – a sustained lateral bending of the caudal peduncle, stiffly holding the causal fin to one side, away from the longitudinal axis ( Johnson and Nelson 1973)
. Tail slapping – a whip-like lashing of the tail at or near the surface, hitting or directing splashes toward a competitor (Compagno et al. 1989; sensu Klimley et al. 1996)
. Torso thrusting – an exaggerated, sustained lateral flexure of the abdominal region into an S-shape, often accompanied by body tilting, sensu Klimley (1985)

Results

Signal logistics and types

The term ‘‘agonism’’ was introduced by Scott and Fredericson (1951) to refer to any behaviour related to fighting and competition.
Agonism embraces a broad spectrum of behaviours related to animal conflict, including fighting, threat, defence, flight, freezing (remaining motionless to avoid detection), avoidance, and appeasement ( Johnson 1972; King 1973; Dewsbury 1978; McFarland 1987).

For all their variety, agonistic behaviours are united by occurrence during conflict situations (Scott 1971).
Conflict denotes a motivational state in which tendencies to perform more than one activity are expressed simultaneously (Manning 1979). Much agonistic behaviour is characterised by motivational conflict between attack and flight, often resulting in vacillation between approach and withdrawal (McFarland 1987).

A ‘‘display’’ is a stereotyped motor pattern involved in animal communication; displays are usually intraspecific and related species often have similar displays (McFarland 1987).
For well-armed contestants, physical combat bears significant risk of injury, which could compromise the feeding or reproductive abilities of both participants (Lorenz 1964). Therefore, in conflict situations, ritualised displays may be more adaptive than combat (Reichert 1982). Due to their conservative structure and the constraints of efficient swimming, sharks have few structures available for signalling. Their only suitable appendages are the relatively highly mobile pectoral and caudal fins (Myrberg 1991) and, in males, the claspers (Myrberg and Gruber 1974; Klimley 1985). Signals are ritualised from non-communicative source behaviours via a process of simplification, exaggeration, decreased performance speed, repetition, and increased stereotypy (Tinbergen 1952). Thus, by definition, shark agonistic displays are conspicuous MAPs elicited in conflict situations, usually between or among conspecifics.

The hunch display of grey reef sharks, however, is not known to be performed toward conspecifics, but is known to be directed toward humans ( Johnson and Nelson 1973; Nelson et al. 1986), great hammerhead sharks (Sphyrna mokarran) and moray eels ( Johnson 1978).
Similarly, blacktip sharks have been documented displaying toward scuba divers before accelerating away (Ritter and Godknecht 2000; Stafford-Deitsch 2000). Since shark agonistic displays are unlikely to have evolved in response to diver encroachment (within the last 50 years), it is likely that shark species perform agonistic displays the same way toward natural predators or competitors as toward humans. This performance conservatism is useful, as it enables scientific study of shark agonistic displays.

Recognising shark agonistic displays

Complex biological structures, such as fins, are often multifunctional (Bock and von Wahlert 1998).
Caudal and pectoral fins of sharks play important and active roles in shark locomotion (Bone 1988). This raises methodological questions about differentiating between use of these fins for locomotion versus signalling.

Use of pectoral fins by sharks for turning is conspicuously different from their use during agonistic displays (Barlow 1974).
Qualitatively, during turning in free-swimming sharks in the wild, the pectoral fins are flexed slowly in a fluid, short-duration (usually shorter than 1 s) motion and PFA of the left and right pectoral fins are unequal, with the fin on the side to which a shark turns usually depressed more strongly than the other, although this is not always the case in slow-moving sharks. This biased pectoral fin depression is contrary to Figure 11 in Wilga and Lauder (2000), which may reflect simplification for clarity or an artefact of inhibited steering in the confines of a laboratory tank. In contrast, during shark agonistic displays, both pectoral fins are held stiffly downward for prolonged periods (usually 5 to 120þs), and bilaterally. Such pectoral fin depression, probably derived from postures assumed by a shark bracing its body in the water column during prey dismemberment would be expected to increase yaw stability and decrease agility. …….

However, sustained bilateral pectoral fin depression, performed in a conflict situation, and accompanied by other common shark agonistic display elements (described subsequently) greatly increase the likelihood of correctly identifying a shark agonistic display.

Species in which displays are known

Agonistic displays are known in at least 23 species of sharks, representing six families.
Sandtiger shark.
This species exhibits a variety of agonistic behaviours not reported by Compagno et al. (1989) in western Indian Ocean individuals. Among the most obvious of these in western North Atlantic individuals is pectoral fin depression accompanied by flank displaying. As in grey reef sharks, pectoral fin depression is elicited in approach–withdrawal conflict situations and is a graded response, with intensity of PFA increasing from 30 degrees to 50 degrees with diver proximity and degree of escape route restriction. This species has attacked divers off South Africa and elsewhere, delivering minimalist bites (not removing flesh) similar to those inflicted on captive conspecifics (Compagno 2001). Another putative agonistic behaviour in this species, often performed in conjunction with pectoral fin depression, is a loud shotgun-like report, generated by exaggerated tail beats during rapid withdrawal that is termed ‘‘tail popping’’ by North Carolina wreck divers (R. Allen, personal communication). Preliminary field tests off North Carolina suggest that likelihood of tail popping increases with speed, directness, and angle of diver approach. Rapid frontal approaches at a downward angle of 30 degrees from the animal’s longitudinal axis seemed to produce the strongest tail popping response. Similar sounds generated by the caudal fin of this species have also been reported from Australia, where groups of sandtigers were observed apparently herding a school of carangids (Cliff 1988). However, it is probable that sound production in this species is caused, at least in part, by cavitation in the wake of its large subterminal lobe), which may make it an artefact of rapid acceleration rather than a display element. Systematic testing of tail popping under agonistic and non-agonistic contexts is needed to resolve this matter. Such testing could include speaker playback of tail popping, which would allow separation of visual and other shark-related cues from the potential stimulus-specific role of popping, analogous to birdsong playback to distinguish mate-attraction from competitor-repulsion functions (e.g. Searcy and Nowicki 2000; Vehrencamp 2000).

White shark.
A variety of named and described agonistic behaviours have been reported in this species, but without supporting evidence (Compagno 2001; Martin et al. 2005). A photo of a white shark hunch display featuring strong pectoral fin depression (PFA¼_70_), was taken off Dyer Island, South Africa in July 2003 (Figure 3i). A possible hunch display by a white shark, apparently contesting access to speared fish and followed by an attack on the spearfisher, was reported in South Africa by Jones (1991), while Collier (2003) identifies four cases in which this species appears to have attacked humans off California in agonistic contexts. Between July 2002 and July 2005, the following agonistic behaviours were performed by white sharks toward conspecifics at Seal Island in False Bay, South Africa: 22 give ways, four follow-give ways, three hunch-give ways, and two stand backs. As these behaviours are well defined and illustrated elsewhere (Myrberg and Gruber 1974; Martin 2003; Martin and Martin 2006), they will not be further described here.. On 27 June 2005, after having been thwarted by the bait handler in repeated attempts to consume the bait, a 3.5m male white shark twice performed RAG displays completely consistent in form and context with those described and illustrated in Strong (1996).

Silvertip shark.
Encroachment by underwater photographers and pursuit by a submersible elicited a partial agonistic display in this species. This display featured slightly stiff-bodied swimming and brief pectoral fin depression (Eibl-Eibesfeldt and Hass 1959, Nelson et al. 1986). Diver pursuit elicited a more elaborate, highly stereotyped agonistic display in at least five different individuals (1.4–1.8mBL) in eight out of 28 (28.6%) trials on non-feeding animals at several offshore reefs on the Great Barrier Reef, Australia. In each successful trial, when a distance of about 2BL was broached by a diver, the test subject accelerated away to a distance of about 15 m. Each shark then turned sharply and charged toward the observer at 3BL/s. When the shark reached a distance of about 2 BL, it strongly depressed its pectoral fins, turned broadside, vertically depressed its caudal peduncle, and —while holding this posture and moving at greatly reduced speed (slower than 0.5BL/s)— gaped its jaws rhythmically (at approx.1 Hz) and vibrated its entire body in a shiver-like motion. This shiver accentuated the white fin markings characteristic of the species and was maintained until the posterior margin of the animal’s pectoral fin base passed the observer’s mid-line. The shark then ceased shivering, raised its caudal fin and accelerated away at 3BL/s with both its pectoral fins strongly depressed . In one trial, a 1.7m female silvertip shark attacked before fleeing; the observer was uninjured but the nose-cone of the DPV was raked by the shark’s upper teeth. Repeated attempts to approach this species for photographic purposes in the Chagos Archipelago, central Indian Ocean, elicited essentially the same display Emery, personal communication).
Galapagos shark.
Aspects of an agonistic display, featuring laterally exaggerated swimming, have been reported in this species (Hobson 1964). During this display, the shark’s head swung through an arc of >90 degrees, which Hobson (1964) interpreted as an attempt by the animal to increase its visual field to maintain visual contact with the diver following it. Sustained diver pursuit elicited a more extreme version of this display on four occasions in non-feeding subadult Galapagos sharks (1.5–2mTL) at Lord Howe Island, Australia. This display was elicited when the observer repeatedly approached from behind to within 2BL of the shark. It featured laterally exaggerated, sub-anguilliform swimming movements, strong bilateral pectoral fin depression (PFA¼ 40 to 60_), gill pouch billowing, and exaggerated jaw gaping at about 0.5 Hz .The display was terminated when all postural and locomotory behavioural elements ceased, except bilateral pectoral fin depression, which was sustained during rapid withdrawal at _3BL/s. A partial agonistic display by a juvenile Galapagos shark, featuring flank displaying and strong pectoral fin depression (PFA¼_70_) was photographed in October 2003 at Bassas da India Atoll, Mozambique Channel (Figure 3l), which may be a nursery area for this species (Hammerschlag and Fallows 2005).

Caribbean reef shark.
Stoneman (1985) reported more than 450 observations of agonistic behaviour, some of which (fraction cannot be determined, since full data are not available) resulted in attacks, in what he identifies as Carcharhinus limbatus (blacktip sharks). However, Stoneman seems to consistently mistake Caribbean reef sharks for this species (Meltzoff 1988; Gruber 1993). Unfortunately, Stoneman has not published his observations, so they are unavailable for independent analysis. Consultation with Stoneman’s scientific advisor indicated that the displays they attributed to C. limbatus featured brief, 1 to 1.2-second pectoral fin dips, punctuated by frequent changes in direction (A. Emery, personal communication). Diver-acclimatised Caribbean reef sharks in the Bahamas were observed in the presence and absence of bait by the author using scuba. Despite high concentrations of sharks (approx. 60 animals in an area smaller than 2500m2), no clear agonistic behaviour was observed without baits, but repeated brief pectoral fin dips (PFA= approx -15 degrees, period=1 Hz) followed a second or so later by 90-degree changes in direction were evident when bait was present, supporting the proposition that the behaviours attributed by Stoneman (1985) to C. limbatus were performed by Caribbean reef sharks. Scharfer (2003) reported similar agonistic behaviour patterns in Caribbean reef sharks at another long-term shark feeding site in the Bahamas, noting that frequency of agonistic acts by sharks depended on feeding technique and that female sharks bumped camera ports (a possible agonistic behaviour) more frequently than males. Systematic observations, preferably of less diver-acclimatised sharks, are needed to verify agonistic behaviour patterns in Caribbean reef sharks.

Sandbar shark.Agonistic displays have not previously been reported in this species, which is a congener of the grey reef shark and ten other species from which such displays have been reported. Partial agonistic displays by subadult sandbar sharks (1.2–1.5mBL), in mixed aggregation with Galapagos sharks (1.8–2mBL), and in the presence of baits, were observed from a shark cage off the north shore of Oahu, Hawaii. This display appeared to be directed toward the observer/cage and featured partial flank display combined with moderately strong pectoral fin depression, increasing from an initial PFA of 5 degrees to a final PFA of 60_ degrees. In more intense versions of this display in Hawaiian waters, subadult sandbar sharks charged toward a diver in the presence of bait at 2–3BL/s. During such charges, the pectoral fins were strongly depressed and, at a distance of 1.5 BL, males veered away from the diver on a perpendicular course, while females continued toward the diver and sometimes rammed him with the snout tip before withdrawing rapidly (D. Fleetham, personal communication).

None of the preceding six species exhibited palatoquadrate protrusion as a component of agonistic displays.

Discussion

Sensory channels of communication

Sharks are endowed with a battery of well-developed senses, responsive to mechanical, chemical, visual, and electrical stimuli (see Hueter et al. 2004, for a recent review).
In theory, any or all of these sensory channels are available for communication (Dusenbery 1992). However, the marine operating environment imposes signal attenuation and limits signal functional range, ability to go around obstacles, transmission speed, and persistence as well as receivers’ ease of locating signal source (Bradbury and Vehrencamp 1998).

Visual signals propagate at the speed of light within limits set by the optical properties of the transmission medium, are directional and non-persistent (McGregor 2005).
Sharks possess a high order of visual sensitivity and acuity, with pupillary dilation and tapetal plates affording some ten times greater photic sensitivity than human eyes under scotopic conditions and at least some species exhibit a well-developed Purkinje shift and true colour vision (Gruber and Cohen 1978; Hueter et al. 2004). There is no reason to believe that sharks cannot see to the limit of underwater visibility which, depending upon habitat, may be as far as 30m (Hueter and Gilbert 1991).
………………

Thus, pending further data, it is provisionally suggested that vision may be the primary sensory channel employed by sharks for agonistic signalling.

What information is conveyed?

Agonistic encounters are framed by uncertainties between or among the combatants.

Agonistic displays provide information about the likely intent and level of commitment of the signaller and may provide information on relative fighting ability.
For example, agonistic displays may emphasise body size, weapons, or status badges, and may also include a tactical element, placing the signaller in a better position to attack or flee (Bradbury and Vehrencamp 1998). Agonistic displays are stabilised by natural selection if the costs are borne by the signaller, in what are termed ‘‘vulnerability handicaps’’ (Vehrencamp 2000). Size is a good indicator of fighting ability, such that competitors of grossly dissimilar size rarely need to fight or display (Krebs and Davies 1993). If, however, combatants are similar in size, ritualised agonistic displays are likely to occur (Bradbury and Vehrencamp 1998).

In assessing the validity of an agonistic display, two sources of uncertainty arise, (1) receiver estimation of signal magnitude, and (2) degree to which a display indicates the likely outcome of combat (Bradbury and Vehrencamp 1998).
Agonistic displays performed at close range to the receiver are likely to be more effective, but they also bear greater risk (Zahavi 1977). Intention movements are incomplete initial phases of behaviour patterns and many threat displays, such as jaw gapes, are ritualized from attack or defensive behaviours (McFarland 1987; Hauser and Nelson 1991). Frontal and lateral agonistic displays occur as a result of motivational conflict between attacking and fleeing, with frontal displays indicative of a tendency toward attack and lateral displays of a tendency toward escape (Fine et al. 1977). Broadside or lateral agonistic displays are widespread among vertebrates (Thomas et al. 1965; Carpenter 1978; Hinde 1982), probably because they emphasise size by presenting the largest possible aspect; such displays also place the signaller at elevated risk of attack, which could signal the sender’s confidence in its fighting ability. Complicating these issues further, individual combatants may recognise a degree of relatedness or have prior experience of one another, but researchers are rarely privy to such parameters (especially in wild or free-ranging subjects), introducing much uncertainty into interpreting isolated agonistic interactions among study subjects

Motivation

Clear agonistic displays are difficult to elicit in sharks, because they require sustained (several minutes) oriented pursuit.
Drawing on visual and possibly other cues, sharks in the wild use their superior swimming ability to set the preferred minimum distance between themselves and divers; if a diver attempts to approach, most simply swim away to avoid contact. However, in some cases, a shark that is approached by a diver will not retreat and will attack instead.

Traditionally, it was thought that shark attacks on humans were motivated by hunger. Baldridge and Williams (1969) were the first to suggest that the character of many shark attacks seemed more consistent with fighting than feeding. Analyses of 1165 case histories archived in the International Shark Attack File concluded that 50–75% of shark attacks on humans were motivated by something other than a desire to feed (Baldridge 1974b, 1988).

The hunch display of the grey reef shark appears defensive in nature and often precedes a rapid, slashing attack with little or no removal of flesh (Fellows and Murchison 1967; Johnson and Nelson 1973; Nelson et al. 1986).
Agonistic displays by sharks have preceded attacks on humans in at least five other species: sandtiger (Compagno et al. 1989; Compagno 2001; and present study), white shark (Jones 1991; Collier 2003), silvertip (Nelson et al. 1986; and present study), Caribbean reef (Stoneman 1985), and smooth hammerhead (Sphyrna zygaena) (Miller and Collier 1981; Collier 2003).

Yet the majority of agonistic displays do not result in an all-out attack.
Nelson (1981, 1983) suggested that sharks may sometimes attack humans because they are regarded as competition for food or another resource. Shark agonistic displays are rarely elicited during feeding or in the presence of bait, which suggests that access to a food resource is not usually a precipitating factor and that divers are not regarded by sharks as competitors. However, in two attacks on divers involving white sharks and one involving a smooth hammerhead, agonistically displaying sharks appeared to contest access to speared fish ( Jones 1991; Collier 2003).

One often-raised possibility is that a displaying shark is defending a geographic area and its resources (territory) for its exclusive use (Baldridge and Williams 1969; Johnson and Nelson 1973; Nelson 1981, 1983).
Defining territoriality in a way that all ethologists agree upon is difficult because different workers emphasise different attributes to different degrees, depending upon their specific research questions. For purposes of the present review, territoriality will be defined following Wittenberger (1981) as more or less exclusive control of a geographic area by an individual or group of individuals by means of implied or overt aggression.

There is no record of reef-dwelling sharks agonistically displaying toward conspecifics — which, having most similar resource needs and exploitation capabilities, constitute the most intense ecological competitors (Nelson et al. 1986).
Direct, rapid approaches by divers are most likely to elicit shark agonistic displays, especially if potential escape routes are restricted or absent. This observation is consistent with the hypothesis (Fellows and Murchison 1967; Johnson and Nelson 1973; Nelson et al. 1986) that these displays signal defensive threat. The open-mouthed, slashing attack that sometimes follows persistent movement toward a displaying grey reef shark, as well as the rapid withdrawal that terminates the agonistic display, are likewise consistent with self-defence rather than feeding.

Pending further evidence on the issue of site-dependent aggression, it seems likely that, in most cases, an agonistically displaying shark is motivated by defence of self rather than of a food resource or territory.

Common features of shark agonistic displays

Agonistic displays of a few shark species exhibit unique elements (e.g. body shiver in the silvertip or corkscrewing in the scalloped hammerhead, S. lewini ), but a number of elements appear common to the agonistic displays of most . The seven most common features (with percentage occurrence in parentheses) include:
(1) stiff or jerky movements (100%),
(2) sustained bilateral pectoral fin depression (100%),
(3) rapid withdrawal (83%),
(4) jaw gaping (70%),
(5) reduced swimming efficiency (52%),
(6) flank displaying (48%),
(7) laterally exaggerated swimming movements (13%).

All these elements are found in the hunch display of the grey reef shark, indicating that its highly overt agonistic display represents an extreme along a continuum of agonistic behaviours in sharks, which range from subtle (in the Caribbean reef shark) to overt (in the grey reef, silvertip, and Galapagos sharks).

Intriguingly, agonistic behaviours that resemble those of sharks in form (arched back, lowered flippers, ritualised jaw gaping, and flank displaying) and context have been reported in at least three species of cetaceans, the spinner dolphin (Stenella attenuata), the bottlenose dolphin (Tursiops truncatus), and the humpback whale (Megaptera novaeangliae) (Overstrom 1983; Connor and Peterson 1994; Johnson and Norris 1994).

Agonistic displays of many unrelated species exhibit convergent properties that honestly inform rivals about the size and fighting capacity of the signaller (Parker 1974).
Whether these cetacean agonistic display elements represent behavioural mimicry of sharks, shared hydrodynamic and morphological constraints, or some other form of convergence is not clear. But in the agonistic displays of both sharks and cetaceans, presentation of offensive weapons and the largest possible aspect come at the cost of decreased swimming ability.
Shark–human interactions

Human pursuit and proximity are sign stimuli known to elicit agonistic displays in sharks.However, intensity of agonistic responses by sharks is context dependent. Johnson and Nelson (1973) found the likelihood that a grey reef shark performs an agonistic display increased with speed and directness of diver approach as well as with degree of escape route restriction. This pattern appears to hold true for most species of actively swimming (i.e. non-benthic) sharks (personal observation).

Almost any object in the environment – bottom features, divers, other sharks, or possibly a boat – can restrict a shark’s escape route and may render it more likely to perform an agonistic display (personal observation).
For example, while swimming near the bottom, individual sharks of most species appear agitated by any diver that maintains position a few metres above the animal’s back, a situation in which diver proximity and pursuit, a suboptimal view of the diver, and restriction of escape routes by the bottom combine to increase the animal’s stress and the likelihood to perform an agonistic display (personal observation; C. Harvey-Clark, personal communication). A tightly packed group of scuba divers more readily provokes agonistic display in solitary sharks than does a single diver or dispersed group of divers and thus may be considered a supernormal stimulus (Bolhuis and Giraldeau 2005).

Use of bait is well known to induce sharks to approach divers more closely than they do without such provisioning (Nelson 1977; Stafford-Deitsch 2000), although use of bait to stage ‘‘feedings’’ for diving tourists is highly controversial (Brylske 2000; Carwardine 2004).
Single-species groups of sharks that have become acclimatised to being fed individually by taking bait impaled on the end of a feeding pole appear relaxed and—despite close proximity of divers and conspecifics—rarely, if ever, display agonistically. In contrast, shark agonistic displays may be elicited toward divers during mixed species feeding events, especially when food is thrown or scattered into the water. Under such conditions, proximity of the bottom and nearby sharks may restrict escape route of an agonistically displaying shark and increase risk of attack against a nearby diver.

Interpreting the significance of these differences is hampered by general lack of data on the extent of learning from past inter- or intraspecific encounters among individual sharks, including the effects of previous agonistic wins and losses.
However, as with any wildlife encounter, ability to anticipate and avoid shark–human encounter scenarios known to agitate sharks, such as those described here, can help reduce the inherent risks of such encounters. Shark–diver interactions are inherently risky but the level of danger can be limited by a diver’s ability to recognise signs that a shark is becoming agitated and respond appropriately (personal observation).

Under unbaited conditions, most sharks simply avoid divers.
However, some individuals, particularly of relatively large and actively predatory species, appear curious about divers and may approach closely. It is probably safest for a diver to allow a shark to approach on its own terms; attempts to approach it will likely cause the animal to flee. A mildly agitated shark may accelerate away for a few body lengths and then resume a more relaxed cruising pace. As a shark becomes moderately agitated by diver encroachment, it often changes course frequently, using short, jerky movements. With increasing agitation, common elements of shark agonistic displays begin to appear.

Most conspicuous of these are rapid, jerky movements and sustained, bilateral pectoral fin depression.
The more agitated the shark, the more stiff and jerky its swimming movements and the more strongly its pectoral fins are depressed. These signs typically escalate in the regular – and thus predictable – patterns outlined here. Intensity of shark agitation increases with diver proximity, speed and directness of diver approach, and the number of sharks. However, in the vast majority of encounters, shark agonistic displays and signs of shark agitation reduce in frequency and intensity with diver withdrawal.

Thus, to a certain extent, an experienced diver can mediate the intensity of shark encounters through his own actions.
It is, however, absolutely vital that divers maintain visual contact with all sharks in the immediate vicinity throughout an encounter. Should a diver be unable to see all sharks in the vicinity at all times, prudence dictates leaving the water as quietly and efficiently as possible. Based on results presented here, it seems likely that a shark performing an agonistic display is signalling that it is in a highly agitated state and on the verge of either attacking or fleeing; if the receiver persists, the shark will attack rather than flee. Such ritualized threats appear to be mostly bluff (the shark usually flees without attacking), but prudence dictates that one should not depend on this. This comparative behavioural review identifies common elements in shark agonistic displays that could assist divers and other ocean users to recognise whether a shark is becoming agitated and may inform human responses to an agonistically displaying shark.
Critical approach distances and diver safety

The best defence, when faced with a shark that appears to be agitated is to avoid exacerbating the situation. If a shark appears agitated (exhibits stiff, jerky movements and/or frequent direction changes) but has not yet begun to display, maintaining visual contact with the animal and withdrawing are likely to reduce signs of the animal’s agitation and stimulate it to withdraw from the area (personal observation).

For divers faced with an agonistically displaying shark, the outcomes of the present review and model suggest that the following safety recommendations may be of assistance:
(1) Face the displaying shark and maintain eye contact
(2) Do not touch, approach, or photograph a displaying shark
(3) If carrying speared fish or collected marine animals, surrender them immediately
(4) Back away from the displaying shark, using smooth purposeful movements; the shark will most likely seize the opportunity to withdraw
(5) Remain on the bottom, with your back toward a reef, wreck, or – if nothing else is available – your dive buddy
(6) Return to, or immediately below (if boat diving), your pre-planned exit point and exit the water unhurriedly but efficiently
(7) During surfacing in open water and while at the surface, check water around and beneath in case the shark follows
(8) If the shark follows, be ready to fend it off with any available object; avoid using your bare hands, if possible, as the shark’s rough skin and teeth may cause injury.

It is clear that much remains to be learned about shark agonistic displays and also about their perception of and interactions with humans. Further study of agonistic behaviour in sharks is likely to pay dividends not only in a richer understanding of shark social dynamics but also in increased safety in shark–human interactions. With knowledge and care, sharks can be approached in their natural habitat and observed at close range in relative safety and with minimal observer impact. Such direct observations are likely to provide new insights into subtler aspects of shark social behaviour.

Are you still with me?
Here’s what I learn from reading this.

• Remember: it seems likely that, in most cases, an agonistically displaying shark is motivated by defense of self rather than of a food resource or territory. Thus, rule number one is to avoid any behavior that a Shark may interpret as being threatening.

• Learn to interpret Shark behavior by being alert to any of the tell-tale displays described above: Sharks are highly transparent and predictable if you know what to look for – and that includes accepting that predatory Sharks are predatory Sharks, and not some romantic figment of your imagination! Of interest, on top of the species-specific behavior described above, the paper contains a table describing the following agonistic display elements for Tigers: stiff or jerky movements; pectoral fin depression; jaw gaping; flank displaying; reduced swimming efficiency; ramming with snout and rapid withdrawal – and for Bulls: pectoral fin depression; snout elevation and jaw gaping, to which I would add head shaking; jaw closing and above all, ramming with snout (!). If in doubt, back off!

• Avoid getting too close to the animals. Apart from the painfully trivial and yet apparently often forgotten simple fact that in order for there to be an incident, a human and a Shark need to be in the same place at the same time, Sharks have a personal space which in scientific terms is called idiosphere, defined as the volume immediately surrounding an individual animal (of any species) that it will defend if broached without appropriate signalling or permission. Learn to identify that space by observing the Shark’s reaction and retreat if you have breached its confines. Also, since that space is likely to vary with the degree at which an individual Shark is habituated to divers, always let the Shark swim to you (keep eye contact) by remaining stationary.

• Related but not identical: avoid crowding the animals. What a Shark may interpret as being an obstacle impeding its withdrawal may not be readily discernible to you, as in another group of divers or, as exemplified by the paper, swimming above it whilst it is close to the bottom (Tiger Beach anybody?). By the same token, do not assertively swim towards, let alone chase any Shark, ever.

• Do not touch. Sharks are not pets, reefs are not petting zoos and Sharks are never, ever, underwater scooters!

• Selected baiting is better than indiscriminate dumping. This is totally in line with what we do in Fiji, as we always keep control of the food and can discontinue feeding as soon as we sense (and we sometimes do) that the situation is becoming tense.

• Avoid creating competitive feeding situations. Remember: There is no record of reef-dwelling sharks agonistically displaying toward conspecifics, but still, mistakes do happen and excited Sharks may bite each other, and you, by accident. Moreover, a Shark may regard you as a competitor and act aggressively assertively!

• If in trouble, push back. Our rule for image hunters: as long as you keep your camera between the mouth of the Shark and yourself, you're OK!

Easy – right?
Which once again begs the question, what are those operators thinking who facilitate those unsupervised interactive encounters with large predatory sharks?
Not much it appears - it's always the same combo: ignorance and greed!

Let’s hope that this post will contribute to eliminating the former!