Learning in Sharks - new Paper!

 Beautiful pic of juvenile Lemon Shark. Source: Battling for Bimini. Click for detail!

Cool stuff!

From the paper.

Abstract

Social learning is taxonomically widespread and can provide distinct behavioural advantages, such as in finding food or avoiding predators more efficiently.

Although extensively studied in bony fishes, no such empirical evidence exists for cartilaginous fishes.

Our aim in this study was to experimentally investigate the social learning capabilities of juvenile lemon sharks, Negaprion brevirostris. We designed a novel food task, where sharks were required to enter a start zone and subsequently make physical contact with a target in order to receive a food reward.

Fig. 1 Set-up of social learning experiment: a positions and measurements of zones, target and reward; b schematic of the target mechanism showing covered and exposed position as well as side and front views; and c steps of the food task or trial - click for detail!

Naive sharks were then able to interact with and observe (a) pre-trained sharks, that is, 'demonstrators', or (b) sharks with no previous experience, that is, 'sham demonstrators'.

On completion, observer sharks were then isolated and tested individually in a similar task.

During the exposure phase observers paired with 'demonstrator' sharks performed a greater number of task-related behaviours and made significantly more transitions from the start zone to the target, than observers paired with 'sham demonstrators'. When tested in isolation, observers previously paired with 'demonstrator' sharks completed a greater number of trials and made contact with the target significantly more often than observers previously paired with 'sham demonstrators'.

Such experience also tended to result in faster overall task performance.

Fig. 5 Testing phase: median (±interquartile range) number of physical contacts made with the target and the target cover by individual observer sharks previously paired with demonstrators (D) or sham demonstrators (SD). P\0.05 in both cases, Wilcoxon signed-ranks test, n = 5 - click for detail!

These results indicate that juvenile lemon sharks, like numerous other animals, are capable of using socially derived information to learn about novel features in their environment.

The results likely have important implications for behavioural processes, ecotourism and fisheries.

From the Discussion

It has previously been hypothesised that sharks can form groups for increased foraging opportunities (Jacoby et al. 2011) and that sharks exhibiting feeding behaviour attract nearby conspecifics or heterospecifics (Myrberg et al. 1969; Bres 1993; Klimley et al. 2001). Although we did not determine specific social learning processes, our findings empirically demonstrate the sensitivity to, and likely importance of, social cues in sharks.

These and other recent findings that stress the importance of social behaviour to the efficacy of shark deterrents (O’Connell et al. 2011; Robbins et al. 2011) emphasise the need for further experimentation on how changes in sharks social environment (presence of competing or informed conspecifics) might affect their foraging strategies or performance and exploitation of a novel food source.

As I said, great job - which is of course no wonder!

After all, Tristan is one of Doc's disciples and the whole thing did happen in Bimini as part of a wider endeavor and very much under the supervision and leadership, but undoubtedly also scathing criticism by the great man himself! This is your classical behavioral experiment aimed as testing a previously formulated hypothesis, and this thankfully (and very much unsurprisingly!) involving a control group - as it should be!

Of course we in the Industry knew that already.

There are plenty of examples of Sharks appearing to learn from their conspecifics (and who knows, maybe other species as well?) during baited dives, this from species as vastly different as the Whale Sharks in Oslob or Cendrawasih Bay to, it appears, the Sicklefin Lemons in Moorea.

Here are some examples by Doc himself.

We know from simple observations that throwing a piece of bait to a naïve lemon shark will take about three pieces for that shark to get the idea that the sound of a splash means that food has landed in the water near it. Then you see other lemon sharks watch the smart one and pick it up right away...splash=food.

This is especially so with the larger reef sharks.
It is easy to tell a new, inexperienced (new comer) reef shark from the experienced group. tThe newcomer has no clue when a piece of food is thrown a foot in front of its nose. It just swims on by. A trained shark however will have already associated food=splash and will immediately turn, orient to the sound and gobble up the piece. When the new comer watches the trained group orienting to the sound of bait hitting the water it picks it up immediately and gets it from there on. Additionally the other trained reef shark appear to the sound of the boat when we anchor up at the feeding site with no bait.
They are smart animals but you already know that.

Indeed we do!

We have observed learning in our social Reef Blacktips but above all, in our Bulls where we are convinced that the fact that the newbies follow the correct feeding protocols from the get-go is due to the fact that they have learned to behave correctly by observing the experienced old-timers!

So, what do the findings of the paper mean?

Do they prove that Sharks are intelligent?

No they do not!
They show that juvenile (= an adjective) Lemon Sharks (= a species) are able to learn a task by observing other juvenile Lemons and, as Doc tells me, that they could learn faster than rabbits or cats (= other species) on a conditioned response and could recall the response up to a year.

And what about the other Sharks? No idea!
Hell we don't even know whether those findings extend to adult Lemon Sharks, see the various hypotheses about slower and/or different learning that are being put forth for humans! Maybe Sharks, too, get more set in their ways and are less prone to experimenting as they grow up? I'm asking this as some of our old ladies do things in always the exact same way, likely because they have learned that it works!

My hunch is that if tested, different species will show different results.
And I'm also quite confident that there will be differences at an individual level - and possibly even at the level of gender or life stages, who knows!
I'm also expecting that the results will correlate with the extent to which those species are social (remember this is about social learning - which of course begs the question whether our Bulls are social!), but possibly, also with the extent to which learning is a useful strategy considering the specific Shark's life history - and yes I'm still of the opinion that Whale Sharks come across as being particularly thick!

But one thing is clear, at least to me.
Despite of all those caveats, I too am convinced that far from being the ever lurking instinctive killing machines some quarters would have them be, Sharks are way smarter, and their life history and behavior, way more nuanced and sophisticated - and this paper is yet another step in revealing that fascinating and beautiful tapestry.

Thank you Tristan and thank you Doc!

Weekend Rant!

Time for a rant!

From a message by a friend

Agree that there is much breathy hyperbole and blatant nonsense written about sharks and conservation, but I suppose that this is inevitable when concern is high but facts are few, with the most solid data residing in relatively inaccessible scientific papers.

Generally I take a sanguine or even charitable view toward the popular Jeremiads you have castigated since the goals of the authors are generally in concordance with mine, and these often painfully well-intentioned folks are far more able to communicate values effectively and educate a large audience than someone who uses words like sanguine or Jeremiad, no?
And education does seem to work in the long run.

Totally agree – BUT!
I’m getting terminally irritated that people who purport to be Shark conservationists and are perceived to represent the whole movement continue to make public statements containing ludicrous assertions and statistics.
This is not only not helpful - it directly undermines our efforts by allowing the other side to assert that we’re nothing but a bunch of lunatics who operate with false claims.
Is that what we want?

Yes it’s an old grievance of mine – but enough is enough.
So there.

But first, check out this piece of equine manure!
Very timely indeed – thank you!



Wow!
Pure sharkitarian snake oil!

There are no Shark attacks?
Right!
Please re-read this!

Sharks?
When talking conservation, talking about “Sharks” is utterly useless!
The fact is that “Sharks” are neither threatened with extinction, nor are "they" apex predators – only a small minority of species are apex predators, let alone keystone species, and the species that are particularly at risk of extinction are several large predatory Sharks, many of which are pelagic; possibly some deep water Sharks; and maybe Whale Sharks – full stop!
Other species are doing no better and no worse that any other Fish that is not subjected to exceptional fishing pressure – meaning not particularly great but not particularly catastrophically, either.
List here (search for "Sharks"), criteria here.

The numbers?
The numbers are just that, numbers.
If one does not put them into context by comparing them to what we know about individual species in specific locations, they say nothing about sustainability which is the only thing that counts.
Yes we all know without having to resort to peer reviewed science that many local, and possibly even some global populations of some Sharks have been severely depleted, and that their disappearance is of concern – but for the time being, that’s basically all we can assert.

So far, there has been one single paper trying to shed a light on the actual numbers being caught, and this only based on data from the Shark fin trade. Read it!
The paper is based on a series of (probably plausible) assumptions that are heaped upon more assumptions, and consequently, the results are merely expressed in orders of magnitude. Specifically, the authors come to the conclusion that the fins traded annually came from between 26 and 73 million Sharks, with a median number of 38 million.
Does that really allow us to honestly state that up to 73 million Sharks are being killed each year, as everybody and his dog has started to assert?
Kudos to Seafood Watch for doing it right: It's estimated that tens of millions of sharks are killed around the world each year for their fins is much better - but then again, have they been killed for their fins?

As I said, the above numbers are only about the global Shark fin trade alone.
They do not cover many other Shark fatalities due to bycatch or targeted food fisheries where the fins are not being introduced into the fin trade. Also, that was then and the trade has very likely increased since. It is thus entirely plausible to assume that the “real” number is higher, and it is perfectly OK to say so.
It is however totally unacceptable to make up numbers on the fly, be it as many as 100 million, let alone over 200,000 million (!!!) which is just plain ludicrous and quite frankly, a total disgrace! Yes, I'm being frank! :)
The good news is that I know that somebody is working on a peer reviewed paper about the global number of Shark being killed – but once again, unless put into context, those numbers will mean absolutely nothing!

And what about the Rate of Depletion?
Is it really true that 90% (or 99, or 70 – whatever!) of global Shark stocks have already been wiped out? Compared to which original baseline count, done when, where and by whom?
Where are the data?

And is it really true that Some marine biologist have suggested as soon as 2020 these magnificent creatures may be extinct – and if so, who is claiming such utter baloney?
Those endangered species of Sharks will become commercially extinct long, long before they will become biologically extinct! But there's a caveat: it is however probable that some local populations may have shrunk to the extent that they may have accumulated extinction debt and that they may be too small to be able to withstand the pressure of a large environmental shock, like the current anthropogenic Climate Change – re-read this post!

Shark Finning?
Shark finning does not equal catching Sharks. It is a specific, particularly wasteful and particularly cruel harvesting technique and for these reasons alone, it certainly needs to be stopped.
But is everybody aware that stopping the finning does not necessarily stop the fishing? The most widespread remedy against Shark finning is to legislate that the Sharks must be landed with their fins attached. This reduces the number of Sharks that are being killed as the carcasses take up a lot of space in the hold of the vessels – but as many examples show, Sharks are still being landed with their fins attached in what clearly appear to be unsustainable numbers.
Also, in many third world countries, local fishermen (and poachers!) have already wiped out many of the traditional food fisheries and as a consequence, many people have added Sharks to their menu, meaning that there is a substantial and increasing Shark food- , as opposed to Shark fin fisheries.
Thus, if we want to save Sharks stocks from overfishing, Stop Shark Finning! petitions alone are simply not adequate – we must also campaign for their protection!

Also, not every fin that is being sold has been finned!
Statements like over one hundred million sharks are caught and finned alive are thus doubly misleading!

Cascading Effects?
Yes there is a seminal paper by Myers et al. that essentially shows how the removal of large predatory coastal Sharks in the Northwest Atlantic led to the explosion of the population of Cownose Rays who in turn wiped out the Scallops, and the industry depending on them, in Chesapeake Bay. More details here.
Great paper – but it has one weakness: nobody was harvesting those Cownose Rays!

But in the real world, coastal Sharks are not being selectively removed alone.
Instead, fishermen target both the apex- and the mesopredators (and the prey), meaning that asserting that removing the big Sharks will inevitably lead to a population explosion of mesopredators (many of which are incidentally Sharks!) who in turn will wipe out the grazers which in turn will lead to an explosion of algae who in turn will smother the reefs can be totally wrong.
In a way, it is now us who have unwittingly assumed the role of apex predators and are keeping the lower trophic levels in check – see many terrestrial habitats where most apex predators have all but disappeared but where there has not at all been a total collapse of the system!
I’m not saying it is not so: I’m just saying that the empirical evidence is scarce and that once again, those effects will vary according to habitat and species composition.
See Ferretti et al. for more details!

As to the role of Sharks in their habitat and the widespread explanation that they weed out the sick and dying and thus keep the gene pool of their prey healthy, etc?
Certainly intuitively plausible: but to my knowledge, whereas there is plenty of research about the role of terrestrial predators, such effects have not been conclusively documented for Sharks – yet!

Which brings me straight over to Climate Change and Oxygen Production!
Check this out.



Did you hear that?
Who has come up with the glorious idea of linking Shark conservation to the Oceans’ production of oxygen?
Yes the Oceans provide for about half of the planet’s oxygen production through the photosynthesis by phytoplanktonic Algae and Cyanobacteria (but then again, probably not!). This (incidentally, to a very small extent), and the sea water’s capacity to dissolve CO2 make it that the Oceans are also Earth’s largest active carbon sink.
It is also certainly true that the Oceans have a great influence on the weather, and that millions of people depend on them for food.

But this got nothing to do with Sharks!
The principal threats to oceanic ecosystems are probably Climate Change, Acidification, Overfishing, Pollution and Habitat Degradation – not the fisheries for Sharks!
It is just not plausible and there is certainly no scientific evidence indicating that if one selectively removed all Sharks
- the oxygen production would cease due to the disappearance of phytoplankton
- the oceans would cease to be a carbon sink
- the weather would change
- fisheries would collapse and humankind would starve
or any other similar stupidities that happen to be en vogue among some Shark activists!

Shark Intelligence?
This very much smells like the newest up-and-coming Shark conservation fad.
Does the fact that some Sharks migrate and that they are capable of memorizing locations automatically mean that they are particularly intelligent? Why are some quarters asserting that it is so, when this is in no way being claimed by the authors of those migration papers?
Sorry Richard – I still think you rock! ;)

Are Monarchs particularly intelligent? Wildebeest?
What about Bees who are not only capable of finding and memorizing the location of a food source, but then also fly back to the hive and convey that information to the other bees – so effectively. that those other bees can find the food without being guided there by the finder?
Hell, that’s even smarter than what we know about the so much hyped Dolphins!

Frankly, I dunno.
My gut tells me that migration and spatial orientation are not good indicators for intelligence. Yes it is amazing behavior – but animals doing amazing things are more often than not simply well adapted to their ecological niche, and behavior that comes across as being remarkably clever is often hard wired and the result of evolutionary selection as opposed to volition.
Example? The amazing Anglerfish!
Perfectly camouflaged and provided with an ingenious lure, they are highly successful at ambushing their unsuspecting prey. Totally clever – and yet one of my ichthyological gurus assures me that they dispose of the lowest brain-to-body mass ratio of all Fishes!

Sharks BTW have a relatively high brain-to-body mass ratio, somewhere between Teleost Fishes and Mammals..
But although we all intuitively know what intelligence means conceptually, it is nevertheless difficult to define, especially in animals - and even more difficult to compare, see the Bees and the Dolphins!

When it comes to Sharks, the one person who knows most about the topic is probably Doc who has demonstrated remarkable learning and problem solving capacity in Lemons, very much in line with what we experience daily with our Bulls.
My gut feeling is that as always, different species will display different abilities, and that those predatory species with the widest trophic niches requiring the widest range of predatory strategies and thus the highest adaptive capabilities will be perceived as the most intelligent - but then again, a friend may be on to something when he remarks
Incidentally, since humans filled a generalist predator niche at one time before we graduated to planetary predator class, would we not inevitably tend to think that other generalist predators like sharks are particularly intelligent?
Yes, it's complicated!

Still, I fully agree with Wolfgang that Tiger Sharks come across as being way smarter than, say, Whale Sharks that I incidentally perceive as being particularly dumb - and who incidentally migrate like crazy!

But those are clearly personal perceptions, not objective data.
Whereas I’m convinced that all of our Bull Sharks have distinct personalities and that they develop affinities to specific persons, I also know that we humans have a fatal propensity for anthropomorphism, i.e. for attributing human faculties to animals.
So, yes, let’s love them like crazy – but let us not assert that our feelings are being equally reciprocated, or the like!
Yes Emma very much appears to love Jim (and there’s absolutely no doubt whatsoever that Jim loves Emma!) – but she is very likely being bribed with massive amounts of juicy handouts and is just being the opportunistic feeder Tiger Sharks are!

Having said that, there appears to be clear evidence that the behavior of some Sharks goes well beyond that of mere automatons that are solely driven by genetic programming.
In fact and going back to, say, Tigers and Bulls, aren’t high flexibility and adaptive capability precisely what we would expect evolution to select for in a generalist predator – meaning that some of what we perceive as being intelligent behavior may be genetically encoded, but that there must also be scope for individual decision making, individual learning, individual preferences, individual personality, etc. which may indeed be good indicators for intelligence.
Again, I don’t know - but precisely because of that, I would never proffer any strong statements one way or the other!

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 - see on top!

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 neither omniscient nor 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!

Or, as I said before .

Can we maybe just be a little more humble and less righteous, the more since Conservation is so complicated?
Maybe progress towards more facts and less truthiness (read this!)?
Can we maybe just open our eyes and wonder at the magnificence of what IS instead of trying to make things up?

We are the amateurs.
Can we please listen to what the professionals are telling us – the principal message being that extreme positions (on both sides!) are inhibiting Conservation and appropriate Management measures?
Recent example? Right here – like it or not, the man has a point!

If we want to educate others – let’s educate ourselves first!

And here endeth the weekend rant!

PS Patric's take: WOW!!!

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!
Remarkable!

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.

Enjoy!

********

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.

I love Science!

Check out the video.



Attenborough or no Attenborough: it's of course bollocks.
There's no proof whatsoever that Darwinius masillae, or Ida, is leading directly to us humans and the hype is quite unwarranted.

Are the creationists gnashing their teeth? Undoubtedly!
What however makes me particularly proud is that the principal critique comes from within the scientific community itself. It's of course highly technical but it also spotlights the fact that the relevant paper was published prematurely and without adequate peer reviewing. Check out this useful synopsis on Wikipedia. Remember the Scientific Method?

This is Science at its best.
Contrary to religion, the conspiracy theories and that other esoteric rubbish where criticism is anathema, it thrives and excels whenever it triggers robust dialogue between proponents and dissenters, like in the present case.
The end result will be a consensus opinion that will very likely place Ida where she belongs, an important, but by no means exhaustive piece of evidence for Darwin's Theory of Evolution, just one, albeit important transitional fossil among many many many others.

Science rocks!
Back to the Sharks.

The proper Way

I've recently ranted about frivolous and heartless science and about Shark "experts" proffering ludicrous opinions instead of doing what is to be expected from proper scientists, and that is, to use the Scientific Method:

• ask Questions
• make Observations
• develop a Hypothesis (that is, a theoretical Explanation)
• make Predictions and then
• collect, analyze and interpret the necessary Data (that is, the Evidence, often via Experiments) in order to verify or falsify (that is, to test) that Hypothesis.
• only then, publish the results (as a Model or Theory) and have them re-tested, often by peers.

That is the only acceptable Technique to separate Truth from Belief, Science from Opinion, Superstition, Myth and Religion, fact from fiction, wheat from chaff. Worth keeping in mind when confronted with yet another piece of unproven conjecture.

Apart from "our" very own Juerg and his research on Shark Reef, here are some institutions and individuals who do serious research on the topics of the past rants:

Mexico: Dr Leonardo Castillo from Mexico's National Fisheries Institute has begun equipping thousands of Sharks with satellite, radio and plastic tags to better understand the cause for a recent spate of incidents on the Mexican Pacific Coast. I look forward to his explanations after the results have come in, as it should be. Much more tedious than taking a quick trip to Mexico in order to give a few interviews - but oh so much more credible!

Greenland Sharks: Canada's three Oceans are frequented by up to 41 species of Sharks.
GEERG, the Greenland Shark and Elasmobranch Education and Research Group is currently conducting Research on 3 of them, the Greenland, Basking and Blue , and planning research on the four Lamnids Great White, Shortfin Mako, Porbeagle and Salmon Shark. As far as I can discern, no frivolous killing involved.
The Canadian Shark Research Laboratory conducts research on some of the same Sharks, mostly by examining catches by local fishermen.
Both websites are a treasure trove of information, along with a nifty interactive Shark identification key.




And then, there's of course TOPP, the herculean effort of trying to tag, and thus record the movements of the Pacific Predators, be it cetaceans, fish, Sharks, birds or reptiles. It never ceases to intrigue and amaze me, be it by its sheer scope or by the wealth of information it regularly unveils.

Plenty to discover, plenty to learn.
Enjoy!