Saturday, December 11, 2010

About Shark Attacks

Undoubtedly, one of the Mossad Sharks!

Time for a preliminary post mortem.
Like everybody interested in Sharks, I’ve been closely following the news tidbits trickling out from Sharm El Sheikh and the various opines in the media and the blogosphere.

There’s much of the usual fluff and idiocy - but there’s also some stellar stuff.
Take the “experts”. Whilst many prate and pontificate, I found this remarkable interview with Avi Baranes. Now THIS is the kind of person you gotta consult, a highly reputable Shark researcher who has been investigating those very waters for a very long time – and accordingly, the interview brims with factual information and quietly addresses and dispels the usual myths. Bravo!
Equally noteworthy are the posts by Richard, by the SOSF and by Michael Scholl - however with some caveats that I’d like to address below.

The way I see it, in this specific case, one needs to try and answer the following queries

  • What species are involved. Apparently, the species implicated are Oceanic Whitetip(s) and Mako, both pelagic as opposed to coastal species, which is certainly surprising. I’m particularly surprised to hear about the Mako, because this is very much a specialist predator of fast pelagic Fishes like Tuna and Billfishes, features a very specialized dentition aimed at grabbing rather than cutting, and is exceedingly rarely implicated in attacks on humans. OWTs on the other hand appear to have a much broader feeding spectrum and have the typical generalist dentition of “grabbers” in the lower jaw and “cutters” in the upper jaw, like the equally pelagic and generalist Blues and most Carcharhinids in general. Consequently, OWTs (not Makos) are frequently found feeding on floating carcasses, mainly of cetaceans, where they are able to cut out chunks of meat. They have a well deserved reputation for being highly inquisitive to the point of chasing people out of the water, and have been implicated in a plethora of attacks mainly on shipwreck victims.
  • What induced those pelagic Sharks to come close to that coast where the attacks happened. In the Red Sea, OWTs are normally regularly sighted hundreds of miles further south and I would have expected them to move north, if at all, following their preferred temperature gradient, often in line with migrations of their habitual pelagic prey. Yes they are also known to follow ships but with the above in mind, my gut tells me that the most likely explanation might be environmental, as in weather/temperature/currents/movements of prey rather than the much cited paucity of natural food due to overfishing or selected anthropogenic interventions like chumming and baiting that would only draw in Sharks from a much smaller radius. Of note, the cited dumping of sheep carcasses happened at the end of September and cannot be credibly considered to be causal for events occurring in December.
  • The cause for the attacks, and their interpretation. This may sound trivial but to me, the immediate causes are obviously location, opportunity and stimulus. Firstly, it has to be noted that the coastline drops off precipitously, meaning that snorkelers and swimmers venturing away from shore quickly find themselves in very deep water indeed. Secondly and due to the massive increase of the local tourism infrastructure, the ocean is teeming with aquatic recreationists, greatly increasing the chances for such an encounter. Thirdly, people splish-splashing at the surface send out the exact stimuli that predatory Sharks will consider worth investigating. As to the interpretation of what happened once the Sharks encountered the victims, see below.
  • What can be done so that this will never ever happen again. Barring the complete prohibition to swim and snorkel, or the complete fencing off of areas where people swim and snorkel: nothing at all! As long as people will frequent the Ocean and Sharks will hopefully exist, occasional attacks will continue to occur - but one can certainly minimize the risk by following a set of sensible recommendations, the first one being don't be stupid!
Which leaves the interpretation of those attacks.
Whilst the mainstream media revel in the image that all Sharks are indiscriminate man hunting killers, the pro-Shark faction claims the exact opposite, that Sharks never prey on humans and that all attacks are the result of mere investigation or mistakes.
Both I believe are wrong.

Shark attacks can be defined as incidences where Sharks bite people.
The term thus covers a very wide spectrum of species, behaviors, motivations, triggers etc and any generalizations will inevitably lead to mistakes – thus, please correct me if you think I’m wrong!
Also, barring a personal interview with the perpetrators, the exact causes for these specific attacks will never be known, so whatever conclusions will emerge will only be (hopefully) plausible but ultimately always untestable hypotheses.

In very general terms, Shark attacks can be divided into the following categories.

1. Attacks associated with feeding events, i.e. predation and scavenging.

The most notorious species implicated in this category of attacks are the large predatory Sharks Great White, Tiger, Bull and Oceanic Whitetip.
Whilst large adult GWs appear to be specialist hunters of mammal blubber, the other species are generalists with a broad spectrum of prey and consequently, hunting techniques. It should thus not come as a surprise that the track record here is unequivocal: these Sharks will sometimes attack and prey on humans!

Granted, these events are exceedingly rare.
It is obvious that humans are not the primary prey of any Shark species and let me spare you the long winded and pathetically trivial explanations as to why evolution could not possibly have selected for it. Also, granted, sometimes the Sharks appear not to like (whatever that may mean) what they have attacked and either spit it back out or not bother to come back to completely consume the meal. In GWs, this may be linked to the fact that we may indeed be too lean for a specialized hunter of blubber. In other species, it may be an indication of the fact that the Shark was not very hungry, or that something disturbed it whilst it may have hung off waiting for the victim to stop struggling.
But when limbs go missing and Sharks hang on, those are predatory attacks, period!

Which brings me straight over to the whitewashing.

Yes we love Sharks, yes Sharks are much maligned and we need to work at improving their reputation: but the fact is that large predatory Sharks are dangerous and that they need to be treated with respect and with circumspection!
That makes them neither bad, nor good – that just makes them large predatory Sharks! I’ve said it beforewe need to remain fact based and refrain from creating our own unhelpful stereotypes!

The common pattern of predatory Shark attack has been called Sneak Attack whereby a Shark suddenly turns up (in fact, many survivors claim that they never saw the Shark prior to the attack) and persistently attacks, very much like what happened in Sharm is being described. This is not surprising and only consistent with most attacks by terrestrial predators who relay on the element of surprise in order to approach their prey.

Great Whites sometimes attack Seals and Sea Lions which are close to the surface by sneaking up close to the bottom and then attacking more or less vertically at high speed, resulting in the much publicized predatory breaches.
Some surfers have been attacked in the same way, leading John McCosker to develop the hypothesis of Mistaken Identity, meaning that the GWs attacking a silhouette at high speed may have mistaken a surfer for a Pinniped, especially in murky water. This is certainly plausible, the more as GW are being routinely induced to attack decoys in the same manner.

BUT: this is strictly GW lingo!
This cannNOT just simply be applied to other species! Specifically, this is not how Tigers prey on Turtles (and no film maker goes potting around Hawaii towing Turtle decoys) and it does not apply to each and every “mistake” a Shark may make! Thus, asserting that most Shark attacks are due to Mistaken Identity is a fallacy and as such, nothing more than pseudo-science!

The same applies to Investigative Bites.
Once again, this is GW lingo, as Great Whites are known to test objects and people by (more or less, see Rodney Fox) gently nibbling at them. Rather than being a strictly predatory behavior, this is probably linked to testing food when scavenging and may, or may not result in subsequent feeding.
Other species known to investigate people, snorkelers and divers alike, by mouthing are Tigers and I hear, Lemons – yes, as in TB!

Not Oceanic Whitetips!
They are the picture child for investigation via bumping. They will circle ever closer, the frequency of bumps will increase and if not countered vigorously or if the affected person does not leave the water, this will likely result in a predatory attack, sometimes referred to as Bump and Bite attack. Check out the video here: this is typical behavior and it is pretty obvious that this Shark would not suddenly slow down to apply a gentle test bite! The same apparently applies to Bull Sharks.
Of note, this is different from the ramming with snout mentioned in Martin 2007 that is related to aggression, not predation. Incidentally, Martin does not cite ramming with snout as an agonistic display in OWTs, a further confirmation that in this species, that behavior is linked to predation!

Once again, attributing Investigative Bites to species other that GWs, Tigers and maybe Lemons is mere whitewashing and pseudo-science! It also looks like an attempt to exonerate the Shark from having had bad intentions or the like, something that I find rather peculiar to say the least!

2. Attacks associated with self defense

You may want to go and re-read this: several species of Sharks display behavior that is called agonistic and is linked to self defense. Failure to identify and adequately react to that behavior may lead to what are generally open-mouthed, slashing bites that result in cuts rather than missing tissue.

Attacks on surfers and bathers by small piscivorous Sharks like Blacktips and Spinners (see Volusia County) or the frequent nips on the feet of waders by subadult Blacktip Reef Sharks are commontly referred to as Hit & Run attacks and generally result in mere harmless cuts. They, too, are believed to be the result of self defense as the Sharks may simply have been startled and may have wanted to fend off a perceived attack, or may have previously displayed agonistic behavior that was never noticed by the victims.
These are, by far, the most frequent Shark attacks on people.

Finally, there are the Provoked Attacks, where the people have touched the Sharks, as in the retaliatory bites by Wobbegongs and Nurses that get dragged out from their covers by the tails.

3. Attacks associated with competition

Typically associated with spear fishing, Sharks may bite people when competing for the speared fish. These attacks are thus not aimed at preying on the person but rather, at chasing away a perceived competitor.
Incidentally, the same happens between different Shark species (but apparently not between individuals of the same species): I’ve personally witnessed a Silvertip biting a Nurse to dislodge him from some bait, and filmed one of our Bulls biting away a Lemon who wanted to approach a feeder.

Consequently, when referring to site fidelity in Sharks, one should always talk about residency as opposed to territoriality. The latter implies defense against conspecifics, a behavior that has been observed in many Fishes but apparently, never in any species of Shark!

This is again different from aggression associated with rank.
Sharks do display behavior that may be interpreted as “posturing” and there are even anecdotal accounts of actual bites on conspecifics in the context of social interactions.
Yes, it’s complicated!

4. Attacks associated with mistakes

Sharks make mistakes.
Considering the impressive array of senses they dispose of, this may seem surprising: and yet, they hunt, attack and bite a vast array of objects like boat propellers, metallic structures, decoys, and ingest completely inedible items like the famous number plates and car tires - and most often and fatally, they will be fooled by fishing bait and lures!

Mistaken attacks on humans are mostly associated with Shark feeding and baiting.
Many species of Sharks (and Fish!) are highly competitive and uncontrolled Shark feeding events can quickly develop into Feeding Frenzies where the animals get highly agitated and may end up biting other Sharks or the human spectators by mistake. Equally, Sharks may accidentally bite the feeders’ hands during hand feeding shows, etc.
Again, these are genuine mistakes and neither competitive nor predatory in nature – the latter much contrary to the opinion of the anti-feeding lobby.

Talking of which, you may want to check out these latest statements by Burgess: apparently, the perpetrator of at least two attacks is one and the same Shark! Amazing!
Plus, there’s this: "These are open-ocean sharks that are living in an environment that is food-poor," says Burgess. "So when you do find food, you darn well better take advantage of it. Do they remember things? Sure, they remember where the good places to eat were, and they'll come back." Surprise surprise: I happen to totally agree - re-read this! But... Sharks that may have been conditioned to come and feed on Tuna heads learn to… feed on Tuna heads! Not humans!

There you have it I believe - and again, if I'm factually wrong, feel free to correct me!
Long story short: if we want to be credible Shark advocates, we got to do our homework and first of all, be informed about the animals we love!
Science is always in flux and today’s insights may quickly become tomorrow’s fallacies, meaning that we must keep abreast of the latest research results and not base our knowledge on old publications and approximate hearsay. Most importantly, we the amateur naturalists should never make up things on the fly, nor should we idly re-interpret what is considered to be the accepted consensus.

This does not mean that we should not challenge the current status quo, as that is precisely the process by which knowledge is being advanced!
BUT: the only accepted technique for doing so is the Scientific Method and as always, let me warn against the siren calls and intellectual shortcuts of the self promoters, quacks and charlatans!

All researchers I’ve ever met have always been eager to engage in informed discussions and to entertain different hypotheses, if adequately supported by according observations. Those researchers are not omniscient and also, not omnipresent and often, observations by common mortals like us have greatly contributed to the advancement of scientific insights - so even if you have no academic background, don’t be shy and speak up!
But do your home work first!

In diesem Sinne!

PS read this brand new report - so, how do you interpret it? :)

30 comments:

RTSea said...

Great post, Mike!

DaShark said...

Thanks Richard - I did like yours, too! :)

Allen Walker said...

Great and insightful article, thanks Mike

Jupp said...

This is the best explanation about 'Shark Attacks' and Shark Behavior, that I have ever read. Thanks Mike

OfficetoOcean said...

Great post.

Nice to see you address the "mistaken identity" aspect as well because, personally, I believe this is one of the biggest myths in the mainstream shark media, particularly in this case and I am seeing more and more, the theory that feeding in egypt has conditioned the sharks to associate humans with food, thus meaning sharks will see humans AS food, which in my mind, is just not true.

Well written and good points raised with which I wholeheartedly agree.

Jeremy Stafford-Deitsch said...

Good, clear piece, Mike. I thought I'd muddy the water with a combination of anecdotes and pseudoscientific speculation...

...With all this talk about open water sharks straying into coastal environments and bringing their 'aggression' with them, the converse question arises as to how what are generally presumed to be reef sharks behave in open water.

I suspect their behaviour changes out there too. Of course the reason for such behaviour changes need not be feeding strategy. They might, for example, be moving between (reef?) feeding areas and consider themselves to be especially vulnerable to bigger predators. Nevertheless, our confidence in calling the grey reef shark or the Caribbean reef shark 'reef sharks' is based, to some extent, on the fact that that's where we tend to encounter them. But then that's where we do most of our diving in the tropics. These species are hardly confined to reefs. On the few occasions when I have encountered 'reef' sharks in blue water (grey reefs and, if it be allowed, silvertips) they've behaved differently from how they normally behave on reefs -often boldy approaching and checking me out, generally making it very clear they know where I am for as long as they remain in visible range (whereas on reefs they often seem to be in trance mode). To put it differently, I wouldn't be surprised if you would be in as much danger encountering an 8 foot Caribbean reef shark in blue water as an 8 foot silky.

I should add that in my very limited experience (why would you be out there?) such sharks haven't gone into the OWS's infamous investigation pattern.

Continued...

Jeremy Stafford-Deitsch said...

...And then there is the problem of entering the blue water when there are both dolphins and sharks present. I've been chased right up onto the top of a reef in the Red Sea by a pair of small, crazed silkies that moved instantly into all out aggressive investigation mode - no circling, just bang, all over me. This happened when I had re-entered the water to snorkel after having dived with them. There was a big, bold silky (about 8 feet) on the dive but luckily it didn't turn up with the smaller two when I got back in. These two didn't get to the bumping or biting stage as I managed to attract attention and get picked up in time. But they weren't backing off one inch despite my kicking them with my fins repeatedly (which they soon learned to ignore) - and they were only about 5 feet long. Was there something that triggered their radical switch to all out aggression? I say yes: several bottlenose dolphins were passing over the reef even as I rolled into the water. I presume the silkies thought I was an injured dolphin. In fact, even as I rolled in and saw the dolphins passing by I thought 'Duh! I shouldn't be doing this...' and I was right.

But it's not just silkies. I've had grey reef sharks swarm all over me and ram me when I was above them on the surface - grey reef sharks that, 10 minutes earlier, I was feeding ON the reef where their behaviour was impeccable. When they (about 10 of them) charged up en masse from the reef and slammed into me they didn't hesitate, they didn't care that they are only meant to eat small fishes and that I was bigger than them. And guess what connected this event with the silky episode above? Yup. I had rolled in with snorkel gear to photograph some bottlenose dolphins that were passing over the top of the reef. Of course I'd snorkelled over these same sharks a hundred times before and they'd always completely ignored me. The water is so clear there (Sanganeb, Red Sea) that I could see them 70 feet below moving in trance mode over the sand. But not this time. The second I approached the dolphins and the dolphins reacted, I glanced down and saw all the grey reef sharks zooming up from the bottom and racing not for the dolphins, but for me. They swirled around me, bumped me numerous times, decided I wasn't quite what they had in mind and, quick as a flash, sped back down to the bottom to resume trance patrol.

I could give more examples of the same.

So to throw my own bit of pseudoscientific speculation into the mix concerning Egypt: if, for unknown reasons, you suddenly have offshore sharks moving inshore, offshore sharks that mistake splashing and snorkeling humans for (presumably injured) marine mammals (dolphins especially), then the outcome, to my mind, is, tragically all too predictable.

Do we know if the attacking OWSs did their usual circling/bumping or whether they appear to have just come straight in and attacked?

I'd also ask of the Egypt attacks whether dolphins were spotted at the time.

DaShark said...

1.

Thanks Jeremy!
Interesting and totally in line with my own experiences of being out there in open water – in fact, having learned my lessons, I will never ever ever again jump from a ship to have a dip, nor will I ever again snorkel in open ocean! Being on SCUBA is often plenty scary enough!

Well, lemme do my own bit of speculative prating and pontificating then! 

The open ocean is mostly crystal clear, so “sneaking up” is unlikely to work.
What probably works best are high speed attacks on lonely prey individuals (Makos on Billfishes) or if the prey comes in “packages”, as in schools of Fish or Cephalopods, some form of schooling (think schooling Hammerheads and Squid) and possibly, co-operative hunting. Of note, there’s even a paper that postulates that OWTs resort to aggressive mimicry in order to have their prey attack them, see http://fijisharkdiving.blogspot.com/2009/06/breathtakingly-elegant-and-beautiful.html ! Plus, oceanic Sharks, including Silkies that live in a “desert” where feeding opportunities are few and far between will aggressively investigate any chance for a meal, especially anything splish-splashing at the surface.

With that in mind, when encountering big “coastal” Sharks, eg Tigers who are known to migrate between islands etc out there, I would not at all be surprised to see them display behavior that is totally different from when they are on the reef! Big predatory Sharks with a wide range of prey will have to develop an equally wide range of hunting strategies and will deploy them according to the specific circumstances

DaShark said...

2.

Grey Reefs? Hmmm…
Like probably you, I’ve been around quite a few accidental bites by Reef Sharks resulting in big clouds of human blood, and the Reefs were totally unfazed – completely different from when there’s Fish blood! Also, having seen quite a few Cetacean carcasses both next to the reef and offshore, I don’t remember ever seeing a Reef partake in the meal and thus tend to believe that those species are strictly piscivorous and simply never interested in mammalian meat.

Dolphins prey on very much the same pelagic Fishes and Cephalopods as many Oceanic Sharks and are often encountered together with them (think about the Shortfin Pilot Whales in Hawaii), as they both follow the same prey (think Sardine run). Many Dolphins aggregate (think Spinners that go sleep in family pods but then aggregate into super pods when they move offshore to hunt) in order to forage offshore. Dolphins often corral Fish, a behavior that greatly facilitates predation.
I thus do not quite believe the story that the primary motivation of the Sharks is to follow them in order to then pick out the newborn, dead and dying (different story when it comes to GW following Humpbacks tho). Rather, the Sharks may have learned, possibly even in evolutionary terms, that it is advantageous to stick close to Dolphins in order to partake in those meals - see again the Sardine run.

With the above in mind, the occurrence of both Reefs and Dolphins may have been caused by the fact that they were both preying on the same Fish. I’ve seen those feeding frenzies just off the coast in the Red Sea many a time, especially in the late afternoon.
The aggressive posturing by the Reefs, rather than being predatory, may then have been competitive as in the case of the spear fishermen and aimed at chasing you, a perceived competitor, away from their prey. Or, they may have felt threatened by you and the bumping was agonistic.

Mind you, just my 2c.

As to the Red Sea attacks, no idea how the events unfolded.
Hopefully in the end, there will be a complete public investigative report so that everybody can learn any lessons involved.

My personal hunch, totally speculative:

- environmental factors contributed to those pelagic Sharks moving north of their habitual range

- some event (eg prey, a floating Whale carcass or the much talked about Sheep - who knows) got them to aggregate off Sharm

- once that event was over (the prey dispersed or was dispatched, the sheep were consumed), the Sharks dispersed following the usual well known search patterns and some stumbled across those snorkelers

- the stimuli by the snorkelers triggered the attacks

OfficetoOcean said...

Could it be argued that the difference in behaviour in sharks in the open blue to their behaviour on the reefs could be attributed to the corrolating change in behaviour of their prey?

In an open water scenario, would it be a valid argument to suggest that the sharks levels of aggression relates to the need for ensuring any potential meal opportunity is taken as these opportunities present themselves less frequently than on a thriving reef system?

Just a thought...

DaShark said...

My guess is as good as yours, or anybody's!

But for the sake of the argument.

I would think "yes" when it comes to pelagic Sharks as that seems to be their typical behavior. Being inquisitive and bold can lead to accidents and thus most predators are rather circumspect - but maybe, for the reasons you cite, it is being rewarded in a pelagic environment, and if so, it may even be encoded genetically.

When it comes to species that we define as being "coastal", dunno.

Based on my experience with Reefies, I just do not believe that any aggression they may display towards humans means that they want to prey on us.

As Jeremy points out, a small Reefie that is traveling between reefs may well be as scared as I would be in the same situation and when caught out, the aggression it displays may be interpreted as being agonistic.

Or if in a predatory situation (tho I doubt that Reefies move offshore to prey - but Silvertips apparently do), the aggression may be due to competition.

Long lived large predatory Sharks like eg Tigers on the other hand have been shown to learn individually during their life time and some individuals may have learned that they need to be more assertive when preying offshore.
Maybe.

And anyway, any self respecting Tiger Shark will undoubtedly know that we're not a Tuna!

Plus having said that, I would always be wary of big Tigers, both on the reef and offshore - especially in situations where they have not been conditioned to be "friendly" towards humans!

Who knows David, it's a difficult subject and the more we speculate, the more we're likely to drift out into la-la land.

Wolfgang Leander said...

Very interesting comments!

While I do consider sharks to be predictable to a large extent it makes much sense that a changed environment (offshore vs onshore and vice versa) would change typical behavioral patterns drastically.

I feel very comfortable interacting with conditioned tiger sharks, so much so that I would not fear an encounter with a "wild" tiger in open water - but, yes, as Mike said - perhaps I would find out that tigers are not just gentle "buddhas" after all but could be what most people think they are: aggressive, and potentially lethal predators.

On the other hand, I maintain that the way a diver / snorkeller faces a shark determines the outcome of the encounter.

Staying cool and moving calmly will probably always work. Seasoned shark divers / snorkellers such as Jeremy will act dominantly, even if they get bumped, and will thus be at a much lower risk of being attacked than a frightened novice diver / snorkeller or an unwary swimmer.

Splashing around wildly, swimming away from the shark (I have seen such "dangerous" behavior in a Russian YouTube clip a few days ago) kicking it with the fins, or fists, however, are the best ways to "attract" the shark and make it want to test bite.

I agree with OfficetoOcean that systematically feeding sharks will condition them to associate humans WITH food but never AS food. What's more: Baiting / feeding them will not just condition them but also tame them - well, that is what I think based on my observations.

Whatever the outcome of the ongoing investigations, nothing can substitute personal experiences with sharks - therefore, the problem is that novices will always be at a higher risk than "veterans" - that is just the name of the game. It's a wonderful game, though.

The lessons to be kearned from these unfortunate incidents are quite clear: The shark dive operators will have to assume much more responsibiiity than in the past, and introduce strict safety protocols - it's also the only way to repair the incalculable damage the Sharm dive industry has suffered.

Wolfgang Leander said...
This comment has been removed by the author.
DaShark said...

Bravo Wolfgang, could not agree more - really, with every single one of your statements!
Totally!

Du bist halt doch ein ganz G'scherta, Alter! :)

But... like what has happened in SCUBA diving, there is also this: that the most experienced people suddenly think that they have become invincible and start to behave in ever more "brave", reckless and stupid ways!

As one of the I hope responsible Shark diving operators, I can tell you that our most novice customers are quite easy to handle as they are generally eager to learn and will respect our opinion and guidance - the more as many of the newbies are obviously s... their pants! :)

The problem are generally the old dogs who loathe being told what to do and know it all better anyway. Especially those who tote big cameras!

Not complaining - just an observation!

The Sharkman said...

I totally agree with Jupp, that this is definately the best explanation about "Shark Attacks and Shark Behavior" that I too ever read.

Mike's very detailed disection covers every aspect of a shark attack. His knowledge and hands on experiance with sharks, plus the 100% safety track record of his operation proves that he knows what he is talking about.

The observations and comments made by JSD and Wolfie based on their own experiances with sharks, add to the quality.

My thanks to all of you......

BUT... going back to the Sharm incidents.... I have one question that has not yet been answered in any of the articles that I have read.

Does anyone know the EXACT location of the incidents? "Sharm" covers a large area, and the 35km coastline (approx)between Ras Nasrani and Ras Mohammed varies a lot in depth in some places. Where the incidents reported in Naama Bay itself? How far off shore were they?

Keep up the good work Mike.

Wishing you all a Merry Christmas and a Sharky New Year. Hope to see you in 2011.

Jeremy Stafford-Deitsch said...

This is a good thread.

I certainly agree with Mike that grey reef sharks aren't interested in devouring humans. It would be interesting to know if there are records of them devouring marine mammals. The Galapagos sea lions and fur seals are bitten by sharks (and presumably devoured as well) -I presume the Galapagos shark is the major culprit.

On the Pacific incident posted in this thread this is surely best described as a defensive response by the shark: it was presumably freaked out and thought the unfortunate victim was a predator chasing it. And when it comes to agonistic behaviour culminating in biting it does seem to be the grey reef sharks around those isolated Pacific islands and atolls that are the most stroppy. If it is granted that the grey reef shark of the Red Sea is the same species, it has to be pointed out that the Red Sea variant isn't known to go into the full-blown agonistic display. Perhaps it is relevant that the Red Sea is basically linear with vast stretches of interconnecting fringing reef and offshore ones relatively close by, while those Pacific atoll and island reefs are very much out there on their own. Perhaps the isolation - and need to defend your patch - has made those grey reef sharks especially feisty.

And I agree with Wolfgang about knowing how best to behave when things get cranky. Years ago I was on a dive boat in Papua New Guinea (when there were still lots of sharks). We were anchored off an offshore reef with blue water beyond it. Most of the people were in the water diving, I had just got back. Suddenly the cook on the boat spotted hundreds of spinner dolphins in the blue water about 50 metres beyond the reef that were passing by. She grabbed her mask, fins and snorkel and said she was going to swim with them. Against my better judgement (duh!) I said I would accompany her. We snorkelled over the drop into the blue water beyond and for all of about 5 seconds saw hundreds of spinner dolphins. Suddenly they had all vanished and, being a pessimist at heart, I looked down into the depths. Sure enough there was movement. A lot of movement. I realised that there were hundreds of sharks that were swimming beneath the spinner dolphins. Now they were coming straight up towards us. I shouted over to the cook not to panic but she was already screaming and thrashing around. All the sharks that were zooming up towards us then switched and headed for her. I suppose a gentleman would have screamed and thrashed as well but I kept very still. For a couple of seconds the sharks - grey reef, silky and silvertip - were all over her bumping but not (thank heavens) biting. Then they were all gone, slipping collectively back into the depths and racing off after the spinners.

Jeremy Stafford-Deitsch said...

Sorry gang - my last post has appeared several times and when I try to remove the extras I seem to make matters worse.

Can you remove the multiple posts, Mike?

Thanks.

DaShark said...

This really IS a great thread!
Many thanks to the contributors, this is interesting!

Alex, in http://www.almasryalyoum.com/en/news/report-blames-humans-sharm-el-sheikh-shark-attacks I read that "the attacks were carried out in the area between Naema Bay and Ras Nasranino" which may mean "Na'ama Bay and Ras Nasrani", http://www.dailymail.co.uk/news/article-1337659/Sharm-El-Sheiks-shark-attack-victims-speak-ordeals.html mentions various bays like "Garden Bay" and "Shark's Bay".
Hope that helps.

Jeremy Stafford-Deitsch said...

This -

http://tinyurl.com/2v4q57g

- is my account of when I was chased up onto the top of the reef in the Red Sea mentioned above. Apologies for the title - it was NOT a shark attack. The editor came up with that.

To give an idea of perspective, the first shot is of the large silky (about 8 feet long) that swam quickly and boldy right up to me when I was doing the dive. The smaller silkies were also there but hanging back. The other shots are of the smaller silkies (about 5 feet long) that chased me up onto the top of the reef (there was no one else in the water when I got back in). I am shooting with a Nikonos and 15mm wide angle lens so those sharks are a lot closer (and a bit bigger!) than they look. I am swimming on my back and trying to keep my fins between me and the sharks (as well as kicking them every chance I could). They absolutely would not retreat and in fact came closer and closer despite all my efforts to drive them off.

OfficetoOcean said...

Jeremy, do you mind me asking you something?

Have you been back to the sanganeb recently?

Your book "Shark - A Photographer's Story" is actually my favourite book and a huge influence on me and that chapter is my favourite and because of that it is an area I am very keen to visit myself...

I don't want to deviate from the thread to much so apologies to everyone but this is the only chance I've had to ask you, I hope nobody minds...

Jeremy Stafford-Deitsch said...

Thanks for the kind comments. No, I'm afraid I haven't been back to Sanganeb for many years. I'm not diving these days but enjoying this discussion because it's bring back the memories and making me think!

The Sharkman said...

Thanks Mike.

If my memory serves me right, both Shark bay and the Garden are very shallow bays. If that report is correct, 10mtrs away from the jetty is very close to shore.

Topography of the area shows that north of Naama bay, the sandy beaches slope very gently. To the south of Naama, the area has more sharp wall drop offs.

It is very unusual that Mako's and OWT come that shallow and that close to land.

OfficetoOcean said...

No probs Jeremy, it really is a great piece of work and still after all these years my absolute favourite shark book of the very, very many I own, always good to pass on some positivity to people who have done something worthy of praise! In fact it is one of the top 3 things that encouraged me to do what I do so thank you!

Sharkman, the topography at Na'ama Bay is actually quite interesting and fairly uniform across that stretch of coastline in that it drops off quite steeply and fairly close to shore as well. What is also worth noting is that that part of Sharm attracts large predators such as Naploeans and Morays close to shore, in fact I was lucky enough to get very close to a cat and mouse display from both the aforementioned animals only 50 or so yards off shore and both were easily five foot plus in length!

What hasn't really been mentioned is this, many of the the dive centres have a fleet of dive boats, these boats drop divers off from their final dives then move away to around 100 yards off shore and the crew will often spend the night on the boats. They eat on those boats in the evening as well and it's often fish caught while the divers are diving during the afternoon (I have seen this myself) the disposal of waste from these boats is generally overboard.

I'm not saying this is a cause of what has happened, it would happen much, much more reguarly if it were but it is another source of human "waste" (not literally speaking although that may also be a factor) which finds it's way into these bays.

Shark Diver said...

Mike anyway to post this thread?

I must say this is as refreshing as it gets in terms of rational industry thought, great posts by all.

I have been AWOL with a project for the past few days, I posted your About Shark Attacks last week Mike.

Jeremy your shark observations are spot on.

DaShark said...

Wow!
24 comments - and nobody is at anybody's throats! Amazing! :)

I'm currently writing from an interet cafe between flights in Tonga and will just not be able to access my usual ressources til this Saturday. Patric - can you maybe post a reference, and I double up when I get back?

Jeremy: Sanganeb huh.
Spent 2 weeks there camping on the platform in maybe 77/78, glorious times! Alex/Tamara and Black Jack, and the barge! My favorite however remains Sha'ab Rumi, on that corner with the old Cousteau cage. Gosh, u make me feel old, old, old... :)

Galapagos' hmmm... u're certainly onto s'thing there.
Ron/Val tell me that the Lord Howe ones are darlings, and the Hawiian ones appear to be very mellow indeed. The only ones I kinda "know" are the resident pack on that corner in Wolf who always remind me of (nomen et omen) wolves - somewhat sinister, very assertive and in-yer-face, very "Silvertip" if u get what I mean!

But I would not really consider them "reefies" like say the greys, caribbean, reef blacktips and whitetips. They certainly have pelagic habits (see Hawaii)and anyway, as you know these distinctions are highly arbitrary o start with.
Sharks living in the Galapagos will certainly adapt to the prey available there and I would not at all be surprised if the Galapagos' hunted those Sea Lions.
But there's obviously also GWs, especially in the South with the Humboldt Current - remember that horrible attack on the cruise ship passenger? If I remember correctly, that was off the cost of Peru, right?

DaShark said...

David, about those attacks

I think we should refrain from slipping into the role of armchair quarterbacks here - others are already doing that and quite frankly, so far, the results are well, hmmm, disappointing.
Not that I'm surprised! :)

Hopefully once everybody has analyzed everything that can be analyzed, there will be an official report.
Hopefully, it will be made public and hopefully, it will contain a list of factual information and observations, the official interpretation of the events and the reasons why the "experts" have reached those conclusions.

Then, we can let it rip! :)

Right now we're just groping in the dark and speculating - maybe intelligently but never the less, without the facts, our collective guesses are as good as anybody's!

OfficetoOcean said...

Mike I agree and I only dropped that in as an additional bit of anecdotal info, not to suggest it was anything to do with ehat has happened...

Jeremy Stafford-Deitsch said...

Hi Mike,

I was doing most of my trips to Sanganeb in the 80s (when Jack Jackson was in charge) so I must be almost as old as you!

The reason I treasured Sanganeb was because of the south-west point. Not only did you have the grey reef sharks and schooling hammerheads beyond, but at about 24metres depth on the sand at the start of the promontory there was a coral head covered in superb soft corals. I could work out the direction of the current, stick a dead fish somewhere in it and then get the grey reef sharks to swim into photogenic positions. This produced images where they had a (beautiful) world in which they were a part, as opposed to the endless Shark-as-Monster photos.

Here's an url:-

http://tinyurl.com/2ejs3cd

- click the 'next' button on the lower right and scroll through.

I didn't take the 2 shots of grey reefs on their own (065751 and 065752) but all the others are mine and from either Sanganeb or Sha'ab Rumi. The ones with glorious soft corals and sharks are taken at the same coral head on the south-west point of Sanganeb.

Anonymous said...

Il semble que vous soyez un expert dans ce domaine, vos remarques sont tres interessantes, merci.

- Daniel

DaShark said...

Merci Daniel

Pardonne mon francais, ca fait un peux de temps depuis la derniere fois.

Pas du tout, je ne suis pas un expert!
J'ai simplement fait une compilation de ce que les chercheurs ont publie' sur le comportement des requins.

En effet je ne crois pas qu'il y aie un vrai "expert" dans le champ des attaques de requin car il n'y a pas vraiment des experiments scientifiques qui pourraient verifier ou falsifier les differentes theories.

En consequence, les vrais chercheurs sont tres prudents quand ils publient des commentaires.

Ceux qui font semblant d'en savoir plus sont generalement des amateurs ou bien des "faux prophetes".