Friday, December 31, 2010

A Great White in Fiji!

Click for detail.

Totally amazing!
Yes, this is apparently a picture from Fiji!

The caption reads 'Jaws' of the South Pacific. A shark on the beach, 1956.
I found it by pure chance when leafing through Fiji in the Forties and Fifties, a collection of pictures by local photographer Robertson Rob Ramsey Wright, 1906-1976.

I dispose of no further information.

As Doc just commented White sharks being warm blooded dwell pretty much where they want—inshore to open sea, topical or temperate seas. Also, the latest published Fish list for Fiji, A Checklist of the Fishes of Fiji and a Bibliography of Fijian Fish by Johnson Seeto & Wayne J. Baldwin lists Carcharodon carcharias as a confirmed record.

I have never heard of anybody sighting a GW in Fiji in recent times and would surmise that the records of GWs are very likely more historical than actual, possibly also owing to the quasi disappearance of Humpback whales from Fiji in the 60ies.

But remember this?
And with the Humpbacks staging a tenuous comeback, it appears that one day, we may well be in for a surprise - very much like the good people of Tonga!

Can't wait, actually! :)

Thursday, December 30, 2010

Liquid Mountaineering!

I've been waiting for the occasion to post this.
That moment is now.

Thank you Patric for providing the adequate Sharky context - and you're right, this is waaay out there! :)


Not convinced? Here's the proof!
And here's the making of!

More Bull Sharks in Tonga!

Got this message from not just a pretty face Karen in Vava'u.

This is a photo of 1 of 12 babies that were pulled out of a pregnant mothers belly. The mother was caught up in a net just outside the entrance of the old harbour. Do you know what species of shark it is?

Juerg and I both think that this is very likely a Bull Shark.
Yes it appears not to feature the diagnostic falcate dorsal fin - but that may just be due to the fact that like the tail, it is not yet fully developed, and to the crammed positioning of the fetus within the womb. Compare it to this pic of a small juvenile Bull Sharks from our work in the rivers, and the similarities are certainly striking.

Despite of the fact that 13 Sharks have died, this is actually excellent news.
It now appears highly likely that Vava'u is boasting a breeding population of Bull Sharks! This is quite surprising as Bull Sharks are known to pup in rivers and with the exception of a few more or less extinct volcanoes, the islands of Tonga consist of either raised limestone or small coral keys, and consequently feature no rivers whatsoever.

The Old Harbor in Vava'u is a shallow murky bay that may experience a bit of runoff when it rains but is essentially pure sea water.
The entrance is a known site for annual spawning aggregations of groupers and it is also the location where Karen, Paul and myself stumbled upon two subadult Bull Sharks in 2007. Like this time, one was subsequently caught in a net and I was able to purchase the jaw that provided for the ultimate verification of the species. Having alerted Juerg, he then published this paper documenting the first ever record of Bull Sharks for Tonga.

This is the jaw of that subadult specimen of approx 120cm. Of interest, these upper teeth appear notably narrower than those of the adults, maybe indicating a more piscivorous diet like in the case of subadult GWs.

At the time, we thought that these may be just strays.
Now, it increasingly looks like the Old Harbor may be a nursing area for a local population of Bull Sharks. This is further confirmed by one of the local dive master who having experienced our Shark Dive, now claims that he had come across Bull Sharks in the past but had so far identified them as Bronze Whalers.

All very interesting indeed, and certainly worthy of further investigation!

Wednesday, December 29, 2010

Bravo Doc!

Patric is right - great pic by Daniel!

If threatened by a Shark - hide among the coral!
This, and more life-saving tips on Shark-human interaction in this remarkably stupid feature on the Voice of Russia.

Thankfully, there is Doc - see the comment!
And no, I got nothing to add!

For once!

Tuesday, December 28, 2010


Click on it - and there's more in the link below!

No, not a typo!
Sasha has posted this gallery of toothy Bull Shark smiles and once again (this is getting boring...), all I can say is Wow!

A couple of caveats though!
First and foremost: dear customer, before you run off to pack your super duper wide angle rig & book a trip to Fiji, read this!
By dishing out copious amounts of Vodka to the staff and patiently listening to the ramblings of one of the owners, Sasha has earned himself superstar status and is being granted special privileges, notably the right to take up residence in the infamous pit. It's a symbiotic relationship: we let him do rather stupid things - he publishes stellar pics and reviews!
And no, we do not usually do this - this is strictly a one-off!

Secondly, this is so yesterday! :)
The challenge this season: wallpaper Bull Sharks!
Today, we had again 40+ Bulls which is pretty much unheard of at this time of the year - and despite of our best efforts, we've managed to only identify approximately half of them, meaning that many are totally new! With that in mind, and yes I may be repeating myself, we are very likely aiming at the magical number of one hundred Bull Sharks - yes on a single dive, meaning that this is just the beginning!

So far, this is the picture to beat!

The good news: for this, you do not need to be sitting in the pit!
The bad news: for this, you do not need to be sitting in the pit!
Meaning: no more haircuts! :)

And finally: yum yum yellow, dorky or not? That's a big fat нет-нет!
Yum yum yellow is the exclusive signature of one UW photographer and plagiarizing is punishable with instant excommunication from Wetpixel, Flickr and all related media! Plus, even the great man himself has had the courtesy to observe protocol!

Ceci dit: Sasha, we eagerly await your return!
The staff, with great anticipation - me, with the usual dose of apprehension! :)
See you real soon!

PS just checked out Vitaly's blog and found this.
Getting there! :)

Monday, December 27, 2010

Upon further Reflection!

There’s something I wanted to share with you.
Whenever I post something a little more substantive, there’s obviously a lot going on behind the scenes. This time, I have been severely reprimanded – and been caught out as a total ignoramus in the process!

Nah it’s not about one of my rants.
In fact, those who have earned my respect and thus, the right to criticize me rather like my rants. They know me and know that I have zero (make that −273.15°C) tolerance for stupidity, hypocrisy, bullshit and lies and that I consequently loathe such things as political correctness, new age whackoism, conspiracy theories and religious piousness - and above all, all facets of pseudo-, alternative- and anti-science! They also know that my rants are generally motivated by my own ethical imperatives rather than tribalism or obscure secret agendas of world domination and the like. In my former incarnation, I was a staunch proponent of meritocracy and its inevitable consequence, accountability, and I thus pride myself in being an equal opportunities blamer and praiser – actually, with an emphasis on the latter!
But I’m digressing as always.

No, surprise surprise, I got slammed for this!
Looks like whilst trying to sort through all of that pseudoscientific speculation, I’ve committed the exact same sin I criticize in others!

The contentious issue: my endorsement of this interview with Avi Baranes.
Indeed, I must confess that I’ve been caught up in its overall pro-Shark messaging and have completely failed to properly analyze the specific content of what was being said!
Mea culpa – totally!

My critic will remain unnamed – no, you won’t be able to guess!
Suffice to say that he is highly intelligent and that he totally knows what he’s talking about - and that he shares my passionate aversion for bullshit!
I re-print his critique verbatim, albeit slightly abridged to preserve his anonymity as this was never meant for public consumption. But I do find it highly instructive - and personally, rather humbling! My self esteem is rather, for lack of a better term: robust (did anybody say pompous ass?) and this has definitely pricked that cozy bubble! Somewhat!

Anyway, I wanted to share it with you, if only to show how easily the discourse can slip into utter irrelevance, scientific and otherwise – and this even when the interviewee is a pro who certainly knows better!

So, here's how a brilliant analytical mind has dissected that little interview.
The critic’s comments are in blue.



This interview is not the words of a scientist trying to place sharks in proper perspective. It reminds me of those people that think sharks are nice and need to be invited to tea. Sharks are not nice or mean—as Da Shark said—they are sharks.

In an interview with Haaretz, he sought to make clear that "sharks are actually quite nice." Avi Baranes
Dec. 7, 2010 (Nir Keidar)

Dr. Baranes, the shark attacks we've seen in Sinai recently are considered rare, but three such attacks have been reported in rapid succession. Why is this happening?

It's true that a violent confrontation between swimmers and sharks is an exceptional event. I think there have only been two cases in all our history: with a British English soldier in 1946 and an attack in Eilat in 1974. Unfortunately the film "Jaws" gave sharks a bad name, and unjustifiably so. Many more people are eaten by dogs than by sharks, and this is because sharks are uniquely attached to their own particular food.

More people are eaten by dogs than are eaten by sharks because sharks are UNIQUELY attached to their food????
This assumes that feeding ecology is the sole motivation of why all sharks attack people. I would argue that the evidence does not bear this out. So it can not be that dogs eat more people than sharks because sharks are attached to their food.

So, when there are incidents like this, we have to look for a cause. Sharks attack people when they invade their territory, and then their reaction is aggressive, as it is when they are unable to obtain their natural food.

Territory and aggression are very loaded words.
When a great white bites, kills and consumes at fur seal is the shark being aggressive (one of the “big five” drives) or is it motivated by feeding? Sharks are actually rather unaggressive animals tolerating one and other very well. Even intraspecific aggression is rare in sharks—think feeding in a bait ball.

Most rapacious sharks do not appear to hold territories although they carry a personal space around with them.
Dr. Baranes is mixing up his terms and strongly confusing the issue as well as being just plain wrong considering what we know of social behavior of sharks. Then he finishes this tour de force by stating that they become aggressive when they can’t get their food!
Oh Pleeeeeze!!

Essentially Avi is stating unequivocally why sharks attack and gives the reasons---territoriality and aggression!! Hi suggestions are not even that reasonable even in the light of our poor knowledge of shark behavior. Just think of all the divers who would die with such a behavioral repertoire—aggression and territoriality---when humans enter the water.

In 1974 in Eilat, a Mako shark attacked a German tourist. The shark was caught the next day and it turned out that it had a problem with its spine and could not swim fast.

Now here we see a forensic determination of why this mako fed on the person.
It may or may not be true. However we have seen all sorts of deformities in sharks including blind ones and plastic-ensnared ones that are doing just fine. So while it might be true that the shark could not feed properly it is just a theory not a fact.

This was a shark that usually fed on tuna, and it simply could not obtain its regular food.

What is the regular food of mako sharks?
In fact they have a relatively wide feeding ecology with prey spanning the gamut from marine mammals to cephalopods. I am sure that even a damaged mako can find food or else it world die rather quickly being warm bodied. I can accept the explanation that Dr. Baranes gave but it sounds to me like the experts simply wanted to come up with a reason for the attack that made sense. I would love to read the report to see just how they determined that the shark could not find and catch its “regular food”. Remember: scientists should be skeptical by nature just like attorneys—show me the evidence!!

In Sinai I know of cases where sharks simply bit the legs of Bedouin fishermen who were standing on reefs. This is the response to an invasion by humans into the shark's living space, and this can also happen when divers enter their territory.

What? No!! This is yet another unsupported conclusion.
What if the shark happened to bump into the fisher? I have seen small sharks on the flats swim right through the legs of waders and they might have been bitten if they had frightened them at that moment. So anything from fear to aggression---rare in sharks---could be operating in this example.

Shark territory reaches right up to the beaches in Sinai? Sharks do not apparently hold or defend territories like damsel fishes. Perhaps Dr. Baranes means shark habitat. Territory is a very loaded term.

The Red Sea is one of a kind. It is narrow and deep and that means that whereas in the Mediterranean, sharks are found only in the middle of the sea,

I do not believe this at all.
Avi is apparently mistaking all sharks for pelagic sharks. There are plenty of littoral sharks in the Med. Here is a nice discussion of chodricthyan zoogeography in the Med.

in the Red Sea they can arrive close to the shore. If you go out 50 meters in Eilat, you are already at a depth of 100 meters, so big sharks can get pretty close to the shore. They also approach areas where food is accessible, and by this I mean port areas.

So is Avi saying that shark attacks can be expected to occur more frequently at Port locations?
Is Sharm a port where garbage is thrown? If so wouldn’t sharks be attacking all the time? Actually there are plenty of big sharks like grey reefs that can and do stay close to shore whether there is a drop-off nearby or not. So having the pelagic zone is not a prerequisite for big sharks like great whites or tiger sharks to come close to bathers.

Unfortunately, we use the sea as a big garbage dump.
Three years ago we caught a tiger shark on the northern shore of Eilat and in the laboratory, I found a smaller shark, about 1.8 meters in length, in its stomach, as well as a sheep's head, two chickens, a nylon bag and two unopened jars of mayonnaise.

But why does this not surprise me?
Tiger sharks have perhaps the widest feeding ecology (broadest trophic niche width) of any large rapacious shark and are notorious for feeding on offal. Check the stomach of a copper shark or grey reef and tell me about garbage. By the way you do not have to kill a shark to find out what is on its stomach!

What about Mediterranean sharks?

The Mediterranean is very shallow and so when sharks approach the beach, they are usually females in spawning season who have entered shallow waters to spawn their young. Shallow water is not amenable for large male sharks to swim in.

OK Mike you tell me about whether Avi is blowing smoke here—shallow water not amenable to males? What?

Can you compare the different species of sharks in the Mediterranean and the Red Sea?

In the Red Sea, the temperature does not go below a certain point, so that the corals produce reefs, a kind of refuge for all kinds of marine life. I would say that 80 percent of the fish in the Red Sea live on reefs - a kind of highly accessible food pantry - and so the sharks patrol along reefs. We have 26 species of shark in the Red Sea, include thing Leviathan shark, the largest of all, which pays visits in April and May. It is 12 meters long, but not dangerous. Of the 26 species, there are maybe two that are capable of attacking people. There's no need to make a big deal about this.

Pardonnez moi!
Any shark over 1.5 m is capable of attacking a human. Whether they bite depends on the situation! Even a little 2 kg carcharhinid sharks can bite the sh-t out of you if you grab their tail!!

OK—gotta go. I have highlighted the egregious parts. Happy Holidays

The Mediterranean has more species than the Red Sea, and that's where the great white shark [the star of "Jaws"] can be found, rather than in the Red Sea. To date, there has been no damage to the shark population in our areas, but those in the Mediterranean are under threat because of a reduction in the number of fish. If something is not done to give the fish a chance to recover their numbers, the big predators will be in danger.

Today we have, in partnership with the UN, established an organization to protect sharks from extinction. All Asians love [to eat] shark's fin. They make soup with it, which the Chinese claim strengthens virility. It's true there are lots of Chinese, but that doesn't necessarily make this claim true. Thousands of tuna are used to catch sharks each year; the hunters take the fins and throw the rest back into the sea, and the damage is enormous. Luckily in Israel the shark is a protected animal.

What do you recommend to reduce and prevent shark attacks like the ones we've been witness to recently?

Protect the sea.
Don't turn it into a garbage dump, and prevent pollution. A lot of sewage flows into the sea, and the minute you damage a system, a lot of species are hurt and disappear. It's like a Russian nesting doll: The big swallow the small. If you damage a coral that serves as a refuge for small fish, not only will they disappear, but and whoever feeds upon them will also disappear, and so on down the line,
until the big sharks can't find food.

I suggest we not be afraid of sharks.
We must respect them, and we can look at them in the water. I also suggest that we
refrain from trying to attack them because they will respond and they have the strength and the means to defend themselves. Just enjoy the view. There is nothing more beautiful than a shark swimming in the sea.

About Oceanic Whitetips on BBC Radio 4!

The BBC have done it again!
Yes I confess, I'm a huge fan, especially of the National History Unit in Bristol!

This is podcast #33 of Saving Species presented by Brett Westwood.
It features Sarah Fowler of the IUCN Shark Specialist Group (of which I'm a big fan, too) with some truly unexpected and probably, and equally frighteningly totally correct comments about how some Shark fisheries have become so small that they have basically become irrelevant to the regional fisheries management bodies tasked with preserving them.

And then, there's one Steve Castle (?) with some remarkable statements about the Red Sea attacks. Bravo for putting things into perspective!
Steve I hear studies Shark Behavior - not to be confused with Applied Shark-Human Interaction, which as I understand it is a sub-discipline of Eco-Behavior! Talking of which, boy do I have a treat for you!!!
Keep watching this space! :)

Anyway, the link is here.

Saturday, December 25, 2010

Bullied back into diving!

Great title, marvelous article, great pics!
Thank you so much!

No wonder: the authors are all experienced Bull Shark aficionados.
Richard and Robin are the original discoverers of the juvenile Bull Shark aggregation at Chumphon Pinnacle and this was their first foray to Fiji. I must really say, rarely have we hosted such genuinely nice, unassuming and intelligent people, a true pleasure - which may also go a long ways to explaining why the staff were so eager to get Richard back into the water with the Sharks he so obviously loves!

fltr: Papa, Richard, Tumbi!

Lill is of course our multi-awarded honorary Viking staff photographer, once again showcasing her photographic prowess - and the advantages of being allowed into the ominous pit! Talking of which, Robin, you are herewith being officially upgraded as well - conditions permitting! :)
Guys - you must come back! If present numbers are any indication, this year will again be phenomenal!

The article was first published in Diver but is now online at Divernet.
I must say that it is really spot on in depicting what we do and why - with one caveat, that being that BAD was not founded by Mike, but by James. Who just happens to be visiting, both for his birthday and for the running of the bulls! And for much needed and well deserved R&R after having worked nonstop for 142 days - talk about being crazy!

Once again, Vinaka Vakalevu!
We owe you big time!

South Africa - behold the Bait Ball!

This is the Bait Ball - more implements on Wolfgang's blog post.

Well well - literally!
The Aliwal Shoal operators have come up with a new Shark friendly baiting implement that will once and forever solve the issue of Tiger Shark entanglements and loss of teeth. This has been a communal undertaking where several operators have spent considerable time and funds on finding a solution, and they need to be thanked and commended for having done so.

This will never happen again.
With that in mind and because this is now the past, Wolfgang has given me permission to publish the pictures - this is what got him going!

Where are the teeth? Click for detail.

Does this look like a single event to you?

This begs the question, why did all those people invest all those resources into a non issue?
Remember the backlash? Remember the statements that no Tigers were being hurt? Remember the underhanded whispers and e-mails that the entanglements were a one-off that had been caused by non other than Wolfgang himself who kept yanking on the chain? Because he was just a senile incompetent idiot who was taking too much medication? And that being his usual stupid and stubborn primadonna self, he was not listening to reason but turning against the very people who had gone to such great lengths to accommodate his idiotic requests?

Do you really believe that anything would have happened if he had not raised his voice in alarm?

I say, this still requires closure.
Those who saw what was happening and never said and did anything, learn the obvious lessons. Those who received those emails, remember who wrote them. Those who turned their backs on Wolfgang as a consequence, have a hard look into the mirror.
Notable exception: Allen Walker who channeled his initial anger into productive energy - well done!
Remember the title of my post?

To Wolfgang, what can I say alter Haudegen - you are just simply unmatched and everybody including the Sharks you love owes you big time. Again!
This is Leadership!

And those who wrote those emails?
You owe Wolfgang a retraction and an apology.
Yes it was probably knee-jerk and in the heat of the moment - but now, the heat has dissipated (has it?) and it's high time for the walk to Canossa! The more since it is Christmas! Yallah!
Or not!

Indeed, I'm not holding my breath on this - but I shall be watching.
And I will not be the only one!

Friday, December 24, 2010

The Shark Feeding Paper!

Here it is – finally!
This is now the published paper about Aleks’ work with the Caribbean Reefs.

Here she is talking to David, courtesy of SFS.

From the paper (highlights are mine).

Effects of tourism-related provisioning on the trophic signatures and movement patterns of an apex predator, the Caribbean reef shark

Aleksandra Maljković and Isabelle M. Côté

Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada
Received 26 May 2010; revised 2 November 2010; accepted 28 November 2010.
Available online 18 December 2010.


Wildlife provisioning, i.e. the provision of bait to generate aggregations of charismatic megafauna as tourist attractions, occurs around the world.
This practice is often promoted as an economic incentive to conserve the focal species, yet has stimulated debate based on the potential for risks to human safety and perceptions of behavioural shifts in provisioned populations. We studied a population of Caribbean reef sharks (Carcharhinus perezi) in the Bahamas that has been subject to regular provisioning for >20 years.

We used a combination of focal observations of sharks during feeding events, remote acoustic telemetry and stable isotope analysis of shark muscle tissue to determine the impacts of provisioning on the trophic signatures and ranging behaviour of sharks in this population.
A small number of large sharks monopolised more than 50% of the bait on offer. These ‘fed’ individuals showed significant 15N enrichment in their tissues compared to conspecifics of the same size that failed to obtain bait at the feeding site, and un-provisioned sharks from a control site.

Despite the disparity in trophic signatures, fed, unfed and control sharks exhibited similar degrees of residency at their respective home receiver sites, and travelled similar daily minimum distances.
Thus, despite long-term provisioning of this Caribbean reef shark population, there is no evidence for shifts in the behaviours considered which might affect the ecological role of these sharks.

However, further research is required to examine potential indirect effects of shark provisioning on sympatric fauna and habitat before this activity can be placed within a sustainable marine conservation framework.

1. Introduction

Provisioning wildlife, as a means of enhancing nature-based tourism experiences, is a hotly debated issue (Newsome and Rodger, 2008) which becomes most controversial when involving the feeding of large predatory species (Burns and Howard, 2003; Perrine, 1989).
In these cases, human safety issues are usually at the forefront of the debate, with opponents of the practice claiming the potential for predators to learn to associate human presence and food rewards, and proponents citing a lack of empirical documentation of such links (Orams, 2002). Concerns have also been raised about impacts on the provisioned animals themselves, which have only begun to be empirically examined. Regular provisioning of various predators has been shown to lead to increased population densities and interference competition (Semeniuk and Rothley, 2008), increased frequency and duration of aggressive behaviours (Hodgson et al., 2004; Hsu et al., 2009), impoverished body condition and physiological indications of impaired health (Semeniuk and Rothley, 2009).

Shark-viewing tourism is the epitome of this controversy.
At over 40% of the 267 globally-distributed shark viewing sites detailed by Carwardine and Watterson (2002), some form of attractant (chum or decoys) or bait is used to increase encounter rates and keep the focal species within viewing distance of paying clients. Yet due to the longstanding difficulties associated with studying large marine predators, the basic ecology of most of these shark species, let alone their responses to provisioning, remains undocumented. Nevertheless, the full spectrum of arguments both for and against the practice of shark feeding has been discussed in several recent papers (Johnson and Kock, 2006; Laroche et al., 2007; Meyer et al., 2009).

The contentious nature of shark provisioning has prompted legislation abolishing the practice in several areas of the world, including Florida, Hawaii, the Cayman Islands and South Africa (Carwardine and Watterson, 2002), with mounting pressure for the activity to be banned in others regions (Topelko and Dearden, 2005).
However, the popularity of shark dives, and subsequent success of many shark encounter operations, now makes this activity a valuable source of revenue, particularly in countries that depend on tourism as a major source of foreign earnings (Green and Higgenbottom, 2000; Topelko and Dearden, 2005).

For example, an analysis of the economic impact of shark-related tourism in the Bahamas revealed that in 2007, operators facilitated more than 72 500 shark encounters, generating an estimated $ 78 207 338 input to the economy when all local services used by shark dive clients were considered (W. Cline, Cline Marketing Group, unpublished data).

The strong economic incentive to maintain, or even promote, shark-related tourism may therefore outweigh the perceived negative effects of this activity on sharks, particularly in light of the absence of strong evidence showing such effects.
Because a substantial part of the debate surrounding shark feeding centres on perceived shifts in the behaviour of sharks in response to provisioning (Guttridge et al., 2009), the aim of our study was to quantify the effects of tourism-related provisioning on the trophic signatures and movement patterns of sharks, i.e. factors for which data may be reliably collected and which are expected to reflect direct impacts of supplemental feeding.

We focused on Caribbean reef sharks (Carcharhinus perezi), which are frequently the focal species at shark dive sites in the Bahamas.
The relative abundance of this shark in accessible coral reef ecosystems of the tropical Western Atlantic makes it an ideal model system to examine the impacts of provisioning on apex predators. Specifically, we compared patterns of site fidelity, daily distances travelled and 15N-based trophic signatures of provisioned sharks with those of un-provisioned conspecifics to elucidate the effects of shark feeding on this species.

Our study provides data that are currently missing from attempts to weigh the benefits and disadvantages of wildlife provisioning.
Such information is essential to assess whether provisioning practices can be included in portfolios of management strategies that enhance apex predator conservation awareness and revenues while not conflicting with other preservation goals.

2. Methods

2.5. Data analysis

We categorised individual sharks as ‘fed’ or ‘unfed’ based on bait consumption (see Section 3.1). Fed sharks were those consuming 3% or more of the bait (n = 11 individuals), and unfed sharks were those consuming 1% or less (n = 37 individuals).
These cut-off values represented a natural break in the bait acquisition data (see Fig. 2a). To account for the possible effects of sex- or size-based differences on Caribbean reef shark behaviour, we restricted our analyses of trophic signatures and movement patterns
to female sharks (i.e. the most abundant gender) of more than 180 cm TL, with the stipulation that these individuals had to have attended at least 50% of the focal shark feeding events.

In addition, we included a control group of 10 Caribbean reef sharks to test whether the shark feeding activity per se influenced movement patterns and trophic signatures regardless of any bait consumption effect.
Sharks in the control group were all females of more than 180 cm TL and, as determined using acoustic telemetry, resided mainly near receiver C (Fig. 1), approximately 4.6 km from the shark feeding site. Eight of the sharks in the control group were sighted at shark feeds over the course of the study, but they attended very infrequently (ntotal = 51 sightings; or 0.4 ± 0.03 sightings per shark per month) and none took any of the bait on offer.

3. Results

3.1. Shark presence and behaviour at shark feeding dives

Between 24 May 2007 and 13 February 2009, 97 individual Caribbean reef sharks were identified during 293 shark feeding dives, i.e. 48% of all shark dives conducted during this period.
Of these sharks, 56 were externally tagged to aid identification. Sharks ranged in size from 90 to 280 cm TL (mean ± SD: 160 ± 35 cm), and the sex ratio was strongly female-biased (1:6.5). Overall, the number of sharks present at each feeding dive varied between seven and 55 individuals (mean ± SD: 34 ± 9 sharks), and individual sighting frequency varied widely (mean ± SD: 127 ± 84 sightings, range: 1–261 sightings, or 0.3–89% of feeding events surveyed).

Eleven sharks (11% of all individuals recorded; 2 males, 9 females) took over 50% of the bait on offer (ntotal = 3792 pieces), with no other single shark consuming more than 2% of the remainder.
The sharks eating the majority of the bait were significantly larger (mean ± SD: 198.18 ± 26.0 cm) than the remainder of the study population (155.47 ± 33.42 cm; independent t-test: t95 = 4.08, P < 28 =" 0.76," p =" 0.48;" 26 =" 2.26," p =" 0.12)," 26 =" 2.51," p =" 0.13;" 26 =" 0.98," p =" 0.39)." 28 =" 1.09," p =" 0.35;">

4. Discussion

Substantial tourism industries have developed around the world, which are centered on charismatic predatory species.
While such industries can provide an economic stimulus favouring the non-consumptive exploitation of the focal species, the cryptic nature and low abundance of most predators often necessitates the use of bait to generate larger aggregations and satisfactory viewing opportunities for tourists (Laroche et al., 2007).

The impacts of provisioning for wildlife viewing purposes are generally poorly known (Orams, 2002), and this is particularly true for marine predators such as sharks.
We examined the direct effects of provisioning on the behaviour of an inshore population of Caribbean reef sharks. We found that although a large number of sharks attended feeding events, a very small proportion of sharks acquired bait regularly. Bait consumption resulted in an elevated 15N signature of fed sharks relative to unfed and control sharks, but there was no statistically detectable variation in the extent of movement of individuals across groups.

Our results therefore suggest that the impacts of long-term, regular provisioning on this shark population may be limited, at least in terms of the parameters examined here.

4.1. Shark presence and behaviour at shark feeding dives

Attendance at feeding events varied widely among individual sharks.
Some of this variation, at a seasonal scale, is attributable to reproductive activity. A mass departure of near-term gravid females, followed quickly by many other females, occurred throughout June. None of the returning sharks, the majority of which reappeared at the feeding site in July, was visibly pregnant and most individuals exhibited extensive scars, usually obtained as a result of mating (Pratt and Carrier, 2001). However, some of the variation in daily individual attendance at feeding events also stems from differences in patterns of residency. Some sharks exhibited a strong degree of fidelity to the feeding area, but many sharks arrived at the site opportunistically, perhaps as a result of attraction to the bait or to the aggregation of conspecifics.

The proportion of Caribbean reef sharks successfully acquiring food rewards at shark feeds was very small.
Although this pattern has also been noted in studies of white shark provisioning (Johnson and Kock, 2006; Laroche et al., 2007), it seems surprising here given the larger numbers and tighter spatial aggregation of Caribbean reef sharks at feeding events. Close proximity potentially created the opportunity for multiple individuals to successfully compete for the proffered bait. The fact that only a few large sharks were repeatedly effective at taking the majority of bait suggests that in Caribbean reef sharks, as in many other shark species (Allee and Dickinson, 1954; Bres, 1993), social hierarchies exist in which larger sharks are dominant in competitive situations.

4.3. Residency and movement

Previous studies of animals subject to regular provisioning have shown marked changes in space use and movement of provisioned animals, including increases in the time spent at the site where food is provided and when it is provided (Hodgson et al., 2004; Milazzo et al., 2005; Newsome et al., 2004; Walpole, 2001).
Neither shift was evident in our study population. All sharks with transmitters spent a high proportion of their time near a single receiver, regardless of feeding status. Thus, overall, fed sharks did not spend more time at the provisioning site than unsuccessful individuals. In addition, fidelity to a single receiver was evident across the day. Fed, unfed and control group sharks in our study were detected at their respective home receiver sites equally during the morning and afternoon indicating that the regular acquisition of food, or even the potential to acquire food, does not influence the residency patterns of these sharks. Provisioning also did not appear to affect the extent of movement away from home receivers. All sharks travelled similar daily minimum distances suggesting that successful acquisition of bait did not lead to smaller foraging ranges.

Overall, both fed and unfed sharks in our study population exhibited movement patterns that were consistent with previous studies of habitat use in Caribbean reef sharks, which have shown that larger individuals (>110 cm TL) prefer ocean reef habitats near drop-offs (Pikitch et al., 2005) and exhibit site fidelity, but also make wide-ranging lateral (_50 km) and vertical movements (Chapman et al., 2005, 2007).

In light of the small estimated contribution of bait to the overall energetic budget of the majority of sharks, it is not surprising that shark movement patterns appear to be largely unaffected by provisioning.
However, our analyses were restricted to a specific subset of sharks (i.e. females > 180 cm TL) whose behaviour may not be representative of the population as a whole. Future telemetry studies should include a broader range of shark size classes and use active, rather than passive, monitoring to obtain more accurate estimates of daily space use.

Previous studies of the movement patterns of marine fish in response to provisioning have yielded conflicting results.
Fish abundance – the most commonly reported proxy for movement – is often higher at feeding sites than at control sites, or during feeding than at other times (Ilarri et al., 2008; Medeiros et al., 2007; Milazzo et al., 2005; Newsome et al., 2004; Semeniuk and Rothley, 2008), but this effect is highly variable among species.

Many taxa, in both tropical and temperate locations, show no change in abundance or biomass as a result of provisioning (e.g. Cole, 1994; Hawkins et al., 1999; Milazzo et al., 2005).
However, the lack of individual identification in these studies makes changes in individual movement impossible to measure. The most comparable study to our own is a telemetry study of provisioned and un-provisioned stingrays (Dasyatis americana) in the Cayman Islands. In contrast to our results, Corcoran (2006) found that stingrays, which are normally solitary foragers with large home ranges, showed strong site fidelity to the provisioning area and reduced activity, which resulted in aggregation. The lack of consensus among fish provisioning studies perhaps reflect differences in, for example, home range sizes, habitat associations, habituation thresholds or tolerance levels of the species at provisioning sites to repeated disturbances.

5. Conclusion: Provisioning as a tool for conservation management of apex predators

The development of effective conservation strategies for apex predators is a pivotal step in the movement towards ecosystembased environmental management (Pikitch et al., 2004; Wallach et al. 2010).
However, large and usually highly vagile predatory species pose a specific set of conservation challenges. For example, their home ranges frequently exceed the boundaries of protected areas (Chapman et al., 2005; Woodroffe and Ginsberg, 1998), increasing the likelihood of negative human-wildlife encounters and susceptibility to hunting or capture.

Given that economic factors play a fundamental role in driving the consumptive exploitation of many apex predators, both on land and in the sea, the key to reducing, or even reversing, population declines may therefore lie in raising the economic value of non-consumptive forms of exploitation.
Our study of Caribbean reef sharks – one of the most abundant apex predators remaining in the Caribbean – suggests that provisioning does not necessarily influence animal behaviour in detrimental ways (Orams, 2002). Because of this, we believe that provisioning, when carefully conducted, has the potential to be an effective strategy that can contribute to apex predator conservation.

Provisioning-based tourism, when accompanied by natural history information, can enhance public awareness of the conservation plight of apex predator populations (Carwardine and Watterson, 2002; Topelko and Dearden, 2005).
Moreover, wildlife-viewing tourism is an expanding and lucrative industry, which suggests good potential for shifting the relative economic gains from extractive to non-consumptive exploitation of apex predators (Clarke et al., 2006; Johnson and Kock, 2006; Meyer et al. 2009; Topelko and Dearden, 2005).

On a cautionary note, our conclusions may not necessarily be extrapolated to other provisioned species – either marine or terrestrial – owing to the potential effects of species-specific responses and differences in provisioning modes.
There may also be indirect effects of provisioning which were not considered here. For sharks, these include increases in diver-sustained damage to habitats at provisioning sites, as well as potential cascading effects of marked local increases in predator abundance.

However, healthy populations of apex predators have been shown to have positive impacts on biodiversity at lower trophic levels (Sergio et al. 2005), thus conservation of these species may deliver wider ecosystem-level benefits.
There is a clear need for further ecological research, coupled with studies of the socio-economic benefits of provisioning-related tourism, before this activity can be safely incorporated within a sustainable-use framework for conservation management of apex predators.

This is just great work, bravo!
I obviously like it because it proves, at least for this population of Caribbean Reefs at this specific feeding site with its specific procedures, that the provisioning has no notable effect on how the Sharks utilize their habitat, meaning that it dispels the myth that feeding Sharks harms the animals.
Bravo also to Stuart Cove who facilitated this!

I also like it because it’s so nifty.
Segregating different sub-groups based on their feeding and attendance patterns, and creating a control group in the process is very smart indeed! If you remember, the lack of control group was one of my principal reservations about the Clua paper on Lemons - and here, we’re being shown a smart way of obtaining that very result through careful observation and lateral thinking! Incidentally, I’m not the only one who took exception to some of the findings in the Lemon paper: some fellow Shark researchers have raised similar concerns, resulting in an interesting discussion – keep watching this space.

Finally, bravo for the caveat!
Indeed, the conclusions may not necessarily be extrapolated to other provisioned species – either marine or terrestrial – owing to the potential effects of species-specific responses and differences in provisioning modes! I really cannot agree more – especially considering the stupid reverse statements about feeding The Wildlife in general and Bears in particular that continue to haunt us!

Still, I do find plenty of similarities to our dive here in Fiji.
In view of the totally different species, I did not expect this and find it totally fascinating! We, too, have periods when the pregnant females leave, shortly followed by most other animals, male and female. We, too, observe different levels of residency, meaning that we have “regulars”, ‘strays” and individuals (e.g. Long John and Valerie) that only turn up during specific periods that appear unrelated to any sexual activity.

Also, we too know that specific individuals nearly always feed when present, whilst other regulars never do – although I could not confirm that successful feeding is liked to size in females. To me, rather than being hierarchical, it really appears to be an individual inclination.
My gut here is that contrary to Reefs where many species aggregate, maybe in family groups, Bulls are rather solitary and that as a consequence, their social etiquette is just not very pronounced – think Polar Bears in Churchill, Ontario. I just cannot see any advantage for such large Sharks to live in groups in a reef habitat where food does not come in large packages. This is contrary to the open ocean with its sporadic big schools of Fishes and Cephalopods where some form of cooperative hunting requiring a more pronounced social etiquette would likely facilitate predation.

Yes, I’m speculating as usual!
The good news being that Juerg is presently working his way through our gargantuan database and the results of years of acoustic tagging – so finally, we will be able to progress from observations, personal speculation and daring (and probably rather stupid) hypotheses by yours truly to proper peer reviewed conclusions!
Can’t wait!

So there!

Merry Christmas and all!

Thursday, December 23, 2010

The Bulls are running!!!

Click for detail!

30+ on Tuesday, 40+ today!
Life is good!

Red Sea - the Experts have spoken!

Did you miss me?
I was marooned in Tonga and no, things there have not improved!

In the meantime, wondrous things have happened!
I’m alluding to my last post about the Red Sea Shark attacks: 28 comments and nobody has hyperventilated or insulted anybody! It’s really a good thread and I invite you to go read it as some highly experienced and intelligent people have shared remarkable insights and entertaining anecdotes.
Very cool indeed!

Also, the experts have published their expert opinions.

Haven’t heard much from Doktor Ritter (hear hear Biminibill!)
All I’ve found is this interview where he has looked at some pics and come to the following spectacular eco-behavioral conclusions

To call this an attack would be wrong. I would call this an accident.
The bite marks I’ve seen on the pictures look like the Sharks were defending themselves. The accident might have happened as follows: first, the Sharks took a bite in order to test the smell
(sic) of that creature – in the same way that we touch something to test its consistence. Then, the victims defended themselves, at which the Sharks took a harder bite because they felt threatened.

Meaning that next time a Shark bites you, let him nibble and do not fight back!

But then, as I’m about to post, I find this !
Again: Wow! Talk about armchair sniping from way out there in left field! And no, I’m not gonna waste my time, and yours, in commenting on the content, the arrogance, the bullshit. If by now you haven’t caught on to this particular con, there’s nothing I could possibly say that will sway your mind anyway!

Which leaves the other three musketeers.
Quite honestly, I was looking forward to their statements with considerable trepidation: after all, if the only PhD (this is wrong) has already come up with this kind of rubbish, what was I to expect from the lowly naturalists?

So there.
In a private post, George Burgess says this.

From Sharm El Sheik, Egypt.

….. For those of you disturbed by the unscientific nature of the subject do not read on (or wait until these results appear in a scientific journal). Others may find the results of my investigation of interest. ……...

From Cairo

The attacks were unprecedented in scope – five in five days (two each on Tuesday and Wed., one on Sat.); major trauma, the last a fatality; all from nearby locations; unlikely attackers for shallow-water attacks.
Three of the non-fatal attacks involved major injuries (loss of limbs) and the victims were very fortunate to survive.

Here’s the kicker: two of the attacks were by an oceanic whitetip and two by a mako (likely a shortfin).
Note the use of “an” and “a” – there is conclusive evidence that a single individual whitetip was responsible for two of the attacks, including the fatality, and a single mako almost surely was involved in two separate attacks. The fifth attack was by a carcharhinid - it may have been a whitetip, perhaps even the same one implicated in the other two, but not enough evidence at this time to say for sure.

The whitetip incident is, I believe, the first documented case of multiple attack by a single shark, although others have been suspected.
Will check on this more when I return and can access the ISAF database.
The oceanic whitetip was identified by distinctive color patterns and a bite mark on its upper caudal lobe in underwater photos of the shark taken just before/after one attack and other photos taken from shore during another attack. The attacker also was tracked to other dive locations post-attack via photos taken by divers. It was a big one - 2.5 m – that also threatened other divers prior to its first attack.

The similarly-sized mako first attacked a wader (!) in hip-deep water then bolted back over the top of the reef into blue water only to reappear a minute later and perhaps 10 m away from the first incident, attacking a snorkler.
The first victim got away with some lacerati
ons; the second was not so fortunate, being mauled on both arms, losing one.

All five attacks occurred in depths no more than 20 m deep.
A very strange situation indeed. It appears that the disposal of sheep carcasses by sailors bringing a load of live sheep in through the nearby shipping channel may have played a part in this, as may have unseasonably high water temp’s.

More to come as we sort through some other data.

In the past, I’ve not been very kind to Burgess.
He does come up with some highly speculative and also, irritating statements - but to his credit, like him or not, he is the go-to man when it comes to Shark attacks. And this time, I must really say that I am impressed! This is interesting, refreshingly factual and also, it does not dwell on gratuitous speculation.
Well done!

Which brings me straight over to this.
You may want to notice that the press release is authored by Collier, an amateur US West Coast GW attack investigator and by Levine, a travel agent, plus 3 unknown Egyptian (?) officials - and no Burgess!
There’s much I could say here about professional qualifications, fake academic affiliations, ongoing feuds and jumping guns & stealing shows – but then again, is anybody in the know surprised?
So, for a change, enough said!

Let’s instead focus on the merits of what is being said.
First and foremost: well done for not having tried to whitewash this – these were indeed genuine, and very likely predatory attacks and not accidents or mistakes or the like!
I also like the reference to the increase in the population of aquatic recreationists augmenting the chances of encounters, and to the specific topographical features whereby the water gets very deep close to the shoreline.

The remainder? Hmmm…

  • The sheep carcasses? Indeed, maybe. But then again, the only confirmed occurrence appears to date back to the end of September which makes for a rather tenuous causal connex to events unfolding two months later. Or not?
  • The depletion of natural prey due to overfishing? First, from everything I hear, the species most targeted and thus depleted in the Red Sea are pelagic Sharks rather than pelagic Fishes, thus leading to the exact opposite conclusions – but granted, I don’t dispose of the numbers and may indeed be wrong. Which of course begs the question whether this assertion is supported by any specific data? Second, I’m hearing the implicit assumption that “Sharks” will go anywhere and eat anything if they are hungry, very much like the proverbial Bears and Wolves are said to approach human dwellings during particularly harsh winters and the like. But Sharks are not Bears and Wolves. With the exception of a few large generalist feeders like Tigers, most Shark species occupy very specific ecological niches where they have evolved to be successful hunters of very specific, in this case pelagic prey. Conversely, individuals that would stray to hunt outside of their ecological niches would be comparatively unsuccessful, meaning that evolution would have selected against this kind of behavior (and incidentally, one could argue that anyway, those Bears and Wolves would still be roaming well within their original habitats from which they were displaced by our invasion). Look at the Med and the North Atlantic: well before the comparatively recent craze for Shark fins and according slaughter of Sharks, fish stocks in those waters were severely depleted - and yet, I don’t remember witnessing any consequent notable increase in Shark attacks. I remain skeptical.
  • Fish feeding attracted the Sharks? Maybe – and if so, I would suspect that the attractant might have been the commotion rather than the fish bait (what was it anyway: bread and the like?). Then again, I have the exact opposite experience here in Fiji. Shark Reef sits on the edge of Beqa Channel that drops down to 300m and where given determined meteorological conditions, there are regular sightings of both Tuna and OWTs – and still, in more than 10 years of baiting with massive amounts of food creating a huge commotion, no OWT has ever visited the reef! See above, reef habitats are simply not the ecological niche of pelagic Sharks, full stop! In brief, way before attracting any pelagic Sharks, the Fish feeding on the coast would have first attracted the local coastal Sharks, among which the ubiquitous Tigers – and obviously, it has not! Again, I am highly unconvinced!
  • Shark feeding? Do I once again hear that Sharks fed by humans will learn to feed ON humans? This is boring – but if you insist: please, do re-read this! Having said this, there is however one caveat: shark feeding does aggregate Sharks and if conducted in the wrong place, e.g. in the vicinity of swimming beaches and the like, it will contribute to increasing the chances of encounters between the Sharks and the aquatic recreationists – and if conducted in the wrong way, e.g. by triggering feeding frenzies, all bets are off anyway! Is this is true and the guys were feeding the Mako, they were really asking for it! As Richard points out, it is very much the responsibility of Shark diving operators to choose the correct locations and procedures, and rogue operators need to be taken to task! Again: snorkeling with large predatory Sharks is just plain stupid - and talk about this having been prophetic! Alas!

This is plenty dangerous enough!
  • Temperature and metabolism? Yes most Sharks are poikilothermic - but it just so happens that the Mako as a Lamnid like the GW is not! Plus, despite the intuitive plausibility of such a hypothesis: are there any data supporting the assertion that Sharks will eat more when ambient temperatures rise, and if so: concerning which species? My personal observations certainly don’t support that hypothesis. Rather, they lead me to the conclusion that instead of falling into a feeding frenzy, Sharks that feel too hot will re-locate to where the ambient temperature is more to their liking, and that different species prefer different ambient temperatures. For instance, in Cocos, the Hammers will always be found just above the thermocline, meaning that in an El Niño year, they will stay deep and during a La Niña, very shallow. Or to take another example, Juerg’s research on the Bulls seems to indicate that they prefer to reside in water between 25 and 27 degrees Celsius. Conversely, our Reef Blacktips seem completely adapted to the much higher temperatures on the reef top. Different Sharks have evolved to function best in different habitats and temperatures and when those parameters change, they just do not behave like mechanical automatons but instead, re-locate to where conditions are best for them. And then, there’s this: many pelagic Fishes like Tuna are highly migratory and fishermen know that both they and the pelagic Sharks that follow them are associated with specific thermoclines, both in terms of depth but also in terms of how warm water expands from the Equator in Summer and contracts back in Winter. With that in mind, would it not be much more plausible to assert that the unusually elevated sea temperatures may have contributed to aggregating both the Sharks and their prey in the Northern Red Sea?
Yes I’m speculating – but so are they!
The fact is that two different species of pelagic Sharks (forget Ritter) have attacked several snorkelers and a wader (!) on the coastline.
This is truly absolutely exceptional and cannot be suitably explained by the usual generalist sound bites about Fish feeding and overfishing – if causal, both would have led to attacks by coastal Sharks first.

So bear with me if I come up with my own set of wild speculations – and let there be no doubt that my guess is as good as anybody’s and that we’ll never know what really went down anyway.
  • An environmental effect, likely the unusually high temperatures, caused pelagic Fishes and the pelagic Sharks that prey on them to wander into the Northern Red Sea
  • An “event” caused the Sharks to approach the coast, the most likely being that their prey went there (think Sardine Run), or that indeed, a Sheep carcass floated there - or the prey dispersed or was consumed and the Sharks approached the coast when swimming one of their typical search patters
  • The stimuli (think splish-splash) sent out by the snorkelers attracted the Sharks who then attacked

And after these simply brilliant deductions (If you can't dazzle them with brilliance, baffle them with bullshit), I herewith end my posts about the Red Sea attacks!

Saturday, December 11, 2010

Climate Change. Right here. Right now.

This is really hard to watch.
Story here, blog post here.

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? :)