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Shark Info 3 / 99   (10-15-1999)

Author

  Intro:

Circling around alleged victims

Shark Info

  Main article:

Shark Behavior: Circling around alleged victims

Dr. E. K. Ritter

  Article 1:

What do you know about shark brains and noses?

Dr. J. F Morrisey

  Article 2:

Film Review: Deep Blue Sea

Shark Info

  Article 3:

Annual Shark Congress in Pennsylvania

Shark Info

  Article 4:

Weak shark protection

Shark Info

  Fact Sheet:

Bull Sharks

Dr. E. K. Ritter


Shark protection without bite

Report by Shark Info

The annual meeting of the American Elasmobranch Society (AES) took place on June 26, 1999, around the same time as the meeting of the IUCN (World Conservation Union) Shark Specialist Group (SSG). Two items on the agenda were discussions on the threat to the survival of 71 shark species (out of a total of 460) and updating the official list of endangered species. A representative of Shark Info participated at the meeting in Pennsylvania, USA.

Only 71 endangered species listed

The first question to arise is why the discussion on endangered shark species was limited to only 71, or only 15% of the approximately 460 known species? Is it because shark specialists lack detailed knowledge since the remaining 85% of the species are rarely caught or examined? Or is it due to a lack of personnel or financial resources needed to gather the missing data?

Participants in the individual teams which establish the lists usually do not charge for their time and expended efforts. It is thus not too surprising that in some areas data is entirely missing or at times available material has insufficient scope and lacks considerable detail. Thus even the degree of endangerment defined by the IUCN must be viewed with some caution.

Generally speaking, fishing is rated as being more important than biology. If no reduction in the amount of a given species is registered, it is rated less endangered than when a reduction is clearly visible. Such justification, with only a seemingly logical basis, may be understandable but should only be considered a tendency when related to sharks. Shark catches are not evaluated based on individuals per net, but statistically are treated like merchandise per ton. Obviously, this may lead to false conclusions, and quite often does, since age factors are not considered. For example, ten young sharks may weigh the same as five adults (see SI 2 / 99: "Requiem for smoked dogfish").

Difficult to assess criteria defining the endangerment level of sharks

In 1994, the IUCN published a list of criteria which attempted to list all species in accordance with their level of endangerment. A total of five categories (A-E) were listed, subdivided into three groups:

  • critically endangered

  • bedroht endangered

  • gefährdet vulnerable

Main emphasis is focused on changes in population size and habitats. Essentially little is known about shark population sizes, and the distribution of only a few species can be determined with a certain amount of accuracy. It is thus not surprising that such standardized criteria have only limited validity, at least as far as sharks are concerned.

The question thus arises why more specific criteria do not exist or cannot be established for sharks, which indeed represent one of the most frequent top predators and play an important role in regulating the ocean‘s ecosystem. After all, hardly another animal group exists which exhibits such differing habits, areas of distribution and reproduction strategies as sharks. Next to population size and distribution, such additional factors as the age of sexual maturity, the number of offspring and the instinct to return to their areas of birth, just to name a few, must be considered in order to define the degree of endangerment for each individual shark species. And yet this is the only way to prevent one or the other shark species from winding up on the "nonendangered" list due to the unavailability of sufficient data, which means risking its partial or complete extinction in the years to come.

Such an effort would appear to be minimal, considering that some shark species need our undivided attention - for extinction is final.

The 71 Species

At the IUCN meeting four of the threatened shark species were classified as endangered, i.e: the Ganges shark (Glyphis gangeticus), Glyphis glyphis, the whitetip soupfin shark (Hemitriakis leucoperiptera) and the Borneo shark (Carcharhinus borneensis). Nine other species, including the white shark (Carcharodon carcharias), were classified as vulnerable and all other species were not considered endangered and thus given a small-risk status or classified with "insufficient data".

Astonishingly enough, various species like the mackerel shark (Lamna nasus), the Spinner shark (Carcharhinus brevipinna), the blacktip shark (Carcharhinus limbatus), the Dusky shark (C. obscurus), the sandbank shark (Carcharhinus plumbeus), the soupfin shark (Galeorhinus galeus), the blunt-nose six-gillshark (Hexanchus griseus) or the basking shark (Cetorhinus maximus) were assigned to two different categories, depending on their geographic habitats. Even though the argumentation that the depletion of some populations due to fishing activities was restricted to certain regions is understandable, we are still dealing with one and the same species with its own art-specific area of distribution. It follows that the species should acquire an unmistakable status - and when in doubt the more critical criteria should always prevail.

Not all threatened species are registered

Many shark species are too rare to appear in statistics: The "71" list thus only mentions species which may actually show a decline in fishing statistics, like the just recently discovered megamouth shark (Megachasma pelagios) or the Ganges shark (Glyphis gangeticus), a known rare species. Many species thus fall through the net established by the IUCN.

As the IUCN finally began to quantify the degree of threat to sharks, some employees at Shark Info were asked to describe every species which they suspect may be subject to population reductions. Here the problem is the question itself, because it is exactly many of these rare species which practically never appear in catch statistics that are categorized as being nonendangered because of missing or inadequate data (data deficient).

At least for sharks, IUCN criteria should be defined and adapted in a way which also guarantees the immediate protection of some rare species. Of course, applying this protection is another problem since fishermen cannot easily identify less known shark species. This may possibly only be achieved by imposing high penalties to induce them to reject and return to the ocean any species unknown to them.

Fast reaction is not possible

As already reported in the last issue of Shark Info, the FAO (Food and Agriculture Organization) believes that the establishment of a worldwide management and observation plan for sharks is unavoidable. However, at the present there is no way to establish an immediate interim-protection for certain species. If there is justified suspicion that a certain species is endangered, ways must be found to protect such a species in the shortest possible time, without wasting years on lengthy, bureaucratic formalities.

The IUCN

The IUCN or "International Union for the Conservation of Nature" was founded on October 5, 1948, in Fontainebleau, France, under the name "International Union for the Protection of Nature". Later on its initials were changed to IUCN. Today it is called simply the "World Conservation Union" and is the largest nature conservation organization worldwide, including more than 900 governmental or private associations from more than 138 countries. More than 8,000 scientists and other professional people work voluntarily for the IUCN with headquarters in Gland, Switzerland, and 42 subsidiaries around the world. The annual budget amounts to more than 50 million dollars. As an association linked with different organizations, the IUCN can be active both globally and in local communities. The Shark Specialist Group (SSG) is only one of its several specialized work groups.

May be published only by indicating the source: Shark Info



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