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.
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").
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 oceanÔs 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.
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.
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.
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 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.
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