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Report by Shark Info
IIn the Spring of 2001 the public was startled by a series of reports on shark accidents. Shark
Info and the Shark Foundation were virtually inundated with a large spectrum of questions on
sharks, shark accidents and shark biology. We will introduce a selection of these questions
and answers in this and subsequent Shark Infos, as well as in our websites www.sharkinfo.ch
and www.hai.ch. All questions will be answered by Dr. Alexander Godknecht, President of the
Shark Foundation and Editor of Shark Info.
If you have any queries on a special shark topic simply e-mail or fax us shark@shark.ch or
sinfo@sharkinfo.ch or
Fax an +41 1 311 67 22.
- According to numerous media reports, the number of shark attacks seems to be rising. Is
this true and how many attacks have been reported?
The frequency of shark accidents has been rising slowly since the beginning of this century.
Worldwide 70 to 100 shark accidents are registered annually in nonprofessional water
activities by the International Shark Attack File (ISAF). As a rule ONLY 5 to 15 of these
accidents end fatally. This is an extremely small number when compared to the annually held 15
billion bathing, swimming and surfing events.
Still, the number of unreported cases is higher because third world countries, worried about
their image, only seldom inform the world about shark accidents. On the other hand, even the
most harmless scratches are registered by the ISAF as shark attacks, even when these were in
reality only shark encounters.
Statistically, the year 2001 was characterized by a normal accident frequency.
- Why is the number of shark attacks increasing?
The slowly rising accident rate is a question of probability. An ever growing number of people
spend their vacation at the oceanside, so that both the probability of them encountering a
shark and the respective danger of an accident also increases.
Affecting this probability quota is the rising amount of water activities compared to the
rapid decrease in the number of sharks which can even be considered a threat to man.
Considering that 15 billion water events take place annually, one hundred shark accidents is
only a very small number.
Another aspect is the ever increasing international networking of the media. We seldom read
about what happened somewhere in the world a week ago. Such news is not current and thus
uninteresting. However, when a surfer is bitten by a shark in Australia or Hawaii yesterday,
it is inevitably reported by the media. If more reports appear on such accidents, we have the
subjective feeling that the number of these accidents is also increasing.
- How serious are shark accidents as a rule?
When hearing about a shark accident, pictures out of such films as "The White Shark" often
appear in our mind. Many of the shark accidents which the media report on very superficially
for topical reasons are harmless bite injuries. Really serious accidents are rare.
A boy whose head was bitten off by a shark was not actually killed by the shark, but was
already dead from drowning, as proven by a more detailed medical examination performed later
on by the Global Shark Attack File (GSAF). These results, however, did NOT appear in any of
the media.
In addition, practically no deaths were reported in a series of accidents in Florida which
went through the media several months ago. Many of these accidents were collisions with
blacktip sharks whose average size reaches about 1.50 m in length, too small to become really
dangerous to man.
- Do sharks eat humans?
As a rule, sharks do not eat humans because they are not part of their diet. Many of the
examined bite wounds hardly show any tissue loss. The sharks bite, but then immediately
release the victim because they dislike the taste of human flesh. With big sharks such as
white sharks, tiger sharks or bull sharks, such a "test" bite can obviously lead to rapid
fatal consequences due to shock and loss of blood. The fact that so few deaths are registered
shows how rare such accidents with large sharks and humans really are.
- Which species of sharks are really dangerous?
Eighty percent of all shark species do not even get as large as man. This fact alone makes
them harmless. The shark species most frequently involved in accidents are: white sharks
(Carcharodon carcharias), bull sharks (Carcharhinus leucas), blacktip sharks (Carcharhinus
limbatus), tiger sharks (Galeocerdo cuvier), sand tiger sharks (Carcharias taurus) and
hammerhead sharks (Sphyrna spp.).
Accidents with white sharks are presumably overrated, since large bull sharks have the same
bite pattern as medium-sized white sharks, indicating a large probability of mistaken
identification when determining the species.
- Sharks certainly also have the reputation of being "eating machines", partially because
strange objects such as license plates are occasionally found in their stomachs. Why do they
swallow such objects?
This reputation goes back almost exclusively to tiger sharks who are extremely omnivorous and
have the broadest diet.
Metallic objects cause a change in the surrounding electrical field (galvanic currents). Since
sharks use electrical sensors (the ampullae of Lorenzini) to seek their prey, it is possible
that the tiger sharks mistake the metallic objects for prey. On the other hand, there may be
completely different reasons for this phenomenon.
Basically speaking, even if a license plate is found once in a shark's stomach, it does not
mean that we should automatically characterize this as being typical of all sharks. Even
children swallow rather strange objects from time to time, but this does not mean we need
conclude that mankind lives on nails or plastic toys.
- As a representative of the Shark Foundation what is your opinion of shark feedings in
Florida?
Up until now no connection between feeding activities and shark accidents could be proven. The
arguments of the environmental groups are thus based more on feelings rather than facts.
Basically we can approach this subject in two ways:
Biological
Sharks are wild animals and should also be treated as such.
Feeding a shark with a stick or by hand is surely dangerous for man since sharks can be fed
only selectively. Often this may lead to friction among the sharks because of the food and
finally may even lead to injury of the divers. In time this could, however, also awaken
sharks' interest in humans, making them connect people with food. This would not be the first
such case.
Nevertheless, there is one type of feeding which simulates a natural situation: the
chumsicle. This is a frozen block of fish which dissolves slowly in seawater. It looks like a
dead fish floating in the water, quite a normal situation to be found in the ocean. The sharks
can feed on the chumsicle freely according to their natural rank and do not connect the
observers with food since these are usually 10 to 20 meters away from the chumsicle.
Personally I feel that coincidental encounters with sharks under water are substantially more
interesting than the shark rodeos offered by commercial shark diving businesses.
Unfortunately, such encounters cannot always be planned and are thus difficult to sell.
Shark protection and public relations
The market price of average-sized shark meat ranges between 30 to 40 francs. Its fins are
worth between CHF 300 and 500.
This is completely out of proportion to a shark's "touristic market value". On the Bahamas,
for example, one shark has an estimated value of approximately CHF 27,000 - not on a one-off
basis but annually. The slaughtering of hundreds and thousands of sharks in Bahaman waters has
thus stopped. Instead the government strives to achieve the sustainable management of their
tourist attractions. Similar considerations could also help protect the strongly threatened
populations of whale sharks in Taiwan and other Asian countries where more and more whale
shark watching excursions are being offered.
Divers who have some experience with shark encounters can be good ambassadors in the mission
to "rescue sharks". One day soon - hopefully - all governments will feel enough pressure from
both the public and from commercial businesses to force them into pursuing sustainable
management of their shark populations, instead of leaving them to commercial fishermen for
unscrupulous exploitation.
Thus, even though shark feedings cannot be justified from a biological standpoint, feedings
with a chumsicle or whale shark watching represent a compromise between biology and the
protection of threatened shark populations. If shark feedings where to be prohibited in order
to protect them, it is very possible that there would be nothing left to protect.
May be published only by indicating the source: Shark Info
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