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Shark Info 4 / 01   (12-15-2001)

Author

  Intro:

Tragedy

Shark Info

  Main article:

Hammerhead tragedy on Fuerteventura

Volker Berbig

  Article 1:

Ban on feeding sharks in Florida

Dr. E. K. Ritter

  Article 2:

Controlled shark diving in South Africa

Andrew C. Cobb

  Article 3:

Frequently asked Questions

Shark Info

  Fact Sheet:

Smooth Hammerhead Shark

Dr. E. K. Ritter


Questions and Answers

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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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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