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Shark Info 2 / 01   (06-15-2001)

Author

  Intro:

The decline of traditional shark fishing

Shark Info

  Main article:

The decline of traditional shark fishing

Shark Info

  Article 1:

Fishing, fins and the lack of sufficient international controls

Shark Info

  Article 2:

A telephone poll by the nature conservation organizations WildAid and Earthcare in Hong Kong and Taiwan

Shark Info

  Article 3:

Series of shark accidents in Florida: Facts and background

Dr. E. K. Ritter

  Fact Sheet:

Blacktip Shark

Dr. E. K. Ritter


Series of shark accidents in Florida: Facts and background

By Dr. E. K. Ritter

Mid-April in Florida: Within the space of one week seven people were bitten by sharks - a report which was quickly picked up by the news media in all of the U.S. as well as various European countries. None of the bites were serious, they were simply scratches, still it was considered reason enough to precisely reexamine domestic and foreign accident statistics. In Australia two people were also bitten by sharks.

Florida

Florida's unique location and form.

© Shark Foundation

From an international point of view, Florida registers the most accidents. Since 1916 the relevant Institute GSAF (Global Shark Attack File) and the ISAF (International Shark Attack File) recorded 439 cases, 29 of which were fatal. California holds rank two in the number of accidents, but has about four times less accidents than Florida and only ten fatal accidents. The question thus arises as to why considerably more accidents occur in Florida compared to other places. Florida's geographical position and shape are unique. Stretching for a distance of more than six degrees latitude, it separates two oceans and its continental tip reaches into the Caribbean Sea, while the Gulf Stream flows to the north off its eastern coast.

The Gulf Stream and the narrow Florida strait are one reason why many shark species migrate seasonally along the coast of Florida. Still, it is not the favorable current conditions which are the deciding factor for shark migrations, but rather the availability of food, mating and parturition grounds. During their migrations some shark individuals swim very close to the coast.

One reason for the accidents which happened in mid-April off the coast of New Smyrna near Daytona Beach is the fact that on their annual migrations to the north blacktip sharks (Carcharhinus limbatus) encountered surfers. Only very few shark species have been investigated in detail concerning their migrational behavior. Based on current knowledge blacktip sharks are a more heterogenous species when it comes to migrations. Some populations appear to make yearly migrations, others remain in the same region the entire year.

Blacktip sharks in Florida are the species which bite the most, however, their average size of approximately 1.5 meters hardly makes their bites fatal. The causes of accidents with the surfers in New Smyrna were not examined any closer, but as with other shark species - such as the white shark (Carcharodon carcharias) - it is possible that blacktip sharks want to look closer at any objects they see but do not recognize on the water's surface and that in doing so they may bite. This theory appears to be plausible. For example, the "Ponce de Leon" bay is located in the same region where the accidents occurred and where various fish swarms gather to spawn during this time of the year. This circumstance could excite blacktip sharks to a point where their inhibition threshold is lowered, prompting them to look at anything which resembles food.

C. limbatus

Shark accidents in Florida usually involve blacktip sharks, but their bites are not very dangerous.

© Shark Foundation

Despite the frequent accidents, blacktip sharks are not really dangerous. But then which species are responsible for the almost 30 fatal accidents over the past 85 years in Florida?
These accidents can be attributed to large-sized sharks such as bull sharks (Carcharhinus Ieucas) and tiger sharks (Galeocerdo cuvier). The latest fatal encounter with a bull shark occurred in the year 2000 in St. Petersburg, whereby in this case one cannot speak of it as being a real attack. The victim had noticed a large swarm of excited fish and then sprang into the very murky water to observe them more closely. What then happened is currently being more closely investigated by the GSAF (Global Shark Attack File). In most cases it is a string of unfortunate circumstances which lead to an accident. Unfortunately this is always played down or even ignored in reports on shark accidents. It should thus come as no surprise that none of the reports over the past weeks delved into the behavior of blacktip sharks or to last year's incident with the bull sharks in St. Petersburg. On the contrary, reports emphasized the fact that in the year 2000 the number of accidents reached the absolute record of 79, 10 of which were fatal. Another subject presented in all the newspapers was the increase of shark accidents over the past 10 years. Nonetheless, if one looks at the number of increasing people who go swimming each year another tendency can be recognized: namely, a reduction in accident frequency, a fact which does not sell newspapers.

* Dr. Erich K. Ritter is a shark biologist, senior scientist of the Green Marine Institutes and assistant professor at Hofstra University, New York.

May be published only by indicating the source: Shark Info / Dr. E. K. Ritter



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last change: 06-04-2016 10:48