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| Shark! |
August 31st, 2003.
By Professor Fabio Cupul
Permanent Member of SOMEDICYT, the prestigious Mexican
Society for the Dissemination of Science and Techniques.
VERSION EN
ESPAÑOL |
 There
is no question that this cry would cause a most impressive
commotion among people peacefully enjoying a day at
the beach, and there is no doubt that it would cause
them to run out of the water, terrified. However, only
a dozen or so of the approximately 350 living species
of sharks could represent a danger to man (the most
dangerous being the Tiger Shark, the Blue Shark, the
Great White Shark, the White Tip Reef Shark and the
Horn Shark). Also, we stand a better chance of being
split in two by a lightning bolt during an electrical
thunderstorm than of being attacked and devoured by
a shark if we should trespass onto his domain. (Seven
to 25 people die every year because of shark attacks.)
Our aversion towards this animal
group is due to its aggressive facial expression that
certainly doesn’t help its popularity rating.
They are considered as “ugly” and “bad”
animals that do not deserve our compassion. An old saying
states that “the only good shark is a dead shark!”
This situation and the fact that between 30 and 100
million specimens are caught each year (most accidentally
by fishing boats), puts them in real danger of disappearing
and if that should happen, they may take with them to
their graves an endless number of secrets that could
represent salvation for man’s permanence on earth.
Spread throughout the seven seas
of our planet, as well as its rivers and coastal lagoons,
sharks come in a wide range of sizes. There are some
huge ones such as the peaceable and harmless Whale Shark
that feeds on marine plankton, and that can reach 60
feet in length, and tiny ones like the Spined Pygmy
Shark that measures less than 8 inches. Half of all
existing species are less than three feet in length
and 82% of them all are less than six feet in total
body length, the size at which they could be aggressive
with men.
 Not
all sharks are terrifying carnivorous predators, a significant
percentage of them feed on small plants and animals
suspended in water columns. Those are called filter-feeders,
as they filter the water through their mouths and gills
to feed on the tiny plankton that remains behind.
Sharks belong to the elasmobranquios
group commonly known as “cartilaginous fish”
because the skeleton is made of cartilage at the adult
stage. These animals have been the object of commercial
exploitation for centuries. The Samurai in feudal Japan
used its rough skin to cover the handle of their swords,
while in Europe, America and Australia they were fished
for the oil of their livers, rich in vitamin A and an
excellent combustible for lamps, and of course, for
their meat.
For over 2,000 years, the most coveted
dish in China was shark fin soup. Today, it is so throughout
the East Asian world. It is made with the fins of those
majestic beings. But this will not make us forget that
oftentimes, fishermen will cut the fins off the sharks
they have caught and then throw them back into the water,
still alive, though not for long. Apart from the ruthlessness
of this procedure, thousands of sharks are literally
wasted, bringing this resource to its inevitable exhaustion.
In Japanese mythology, sharks were
considered as terrifying animals, which is why warriors
of the rising sun empire would paint jaws on the fuselage
of their fighter planes. For their part, natives of
the Fiji islands believe that sharks can be disarmed
by kissing them. Also, some cultures state that the
shark represents one of the last resting place for the
soul after death.
Sharks are a resource we are wasting
and bringing to the brink of extinction. We take the
corneas of their eyes to transplant them in human beings,
their cartilage is used in the preparation of certain
medicines against cancer (sharks never suffer with cancer)
and in the treatment of burns; their skin provides a
type of leather up to 150% stronger than cowhide or
pigskin (it is also used as an abrasive), among so many
other uses. There is no question that it will be our
fault and disgrace if they should become extinct after
having thrived for millions of years.
Vallarta’s Nature Field Guide -
File 5
The Brown Pelican
 Along
both coastlines of the country, the silhouettes of the
Brown Pelican (Pelecanus occidentalis) fill the skies.
They scan the blue waters of the ocean in search of
fish which, once they’ve been spotted, succumb
to the implacable bombardment of the bodies that nosedive
upon them at incredible speed. Once underwater, the
pelicans open their long, thin beak to deploy a bag
of skin that extends from the base to the tip of the
lower jaw, acting like a huge spoon that catches both
water and fish. When the bird reaches the surface, it
discharges the excess water (that could be as much as
3 gallons) along the edges of its beak while directing
its catch down towards its esophagus, where it will
remain in temporary storage before being transferred
to the stomach to be digested or regurgitated to feed
the offspring. From the 1940’s to date, the pelican
population has been threatened by the indiscriminate
use of pesticides in agricultural lands. The effect
of the intoxication in the birds is reflected in the
eggs they lay. The shells are so thin that they crack
when the bird sits on them to hatch them. Actually,
stopping the use of DDT and replacing it with more “eco-friendly”
pesticides has maintained the natural population relatively
stable. The pelican is one of the largest living aquatic
birds. Its body can reach three feet in height, and
its wingspan up to seven feet. Its plumage is totally
gray in young specimens while adults have brown and
white markings on the head and down the neck, as well
as a large yellowish patch on the forehead.
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