11 July 2005

Sharks - Myth vs Fact

With two major attacks off Florida beaches the last month, sharks are back in the spotlight - unfortunately once again, as a menace to the public.

It's hard to deny the danger sharks pose, but when some time and thought is spent looking at sharks overall, a different picture is often painted.

With this in mind, perhaps we should re-examine some of the most popular myths that keep circulating about sharks--and, the facts, which are not always so well known. Sharks are not exactly our friends, but they are no-doubt an integral part of our planet's watery ecosystems.

MYTH: Sharks will eat just about any bait.
FACT: While some sharks will eat just about any chunk of fish or meat used for bait, most sharks are a lot more finicky, and prefer a lively fish. Even more so, sharks that are fished for as gamefish on the flats will only bite a bait that naturally occurs in that area.

MYTH: Sharks eat all the time.
FACT: Sharks eat periodically depending upon their metabolism and the availability of food in the area. Some sharks, like the lemon shark eat less than two percent of their body weight per day.

MYTH: Sharks attack more at night.
FACT: Sharks may feed more at night, but very few attacks occur at night. Of course this might be due to a tiny percentage of people actually swimming or diving at night.

MYTH: Sharks are poor gamefish and not worth fishing for.
FACT: Sharks make a very good gamefish, with fighting ability up there with most others. Some sharks, the Mako in particular, are a prized gamefish, known for their outstanding runs and jumps. On the flats, small blacktip are often targeted, and respond with drag-sizzling bursts of speed

MYTH: Sharks have to swim constantly to survive.
FACT: Some do, but many others can respire by pumping water over their gills through opening and closing their mouths while at rest on the bottom. Just don't swim up to a motionless shark on the bottom, a startled shark can be quite dangerous.

MYTH: Sharks are trash fish of very little value.
FACT: Sharks are a critical part of marine ecosystems, especially in keeping the food chain in order. Without sharks, various species of fish would be very susceptible to disease and over population.

MYTH: Sharks have poor vision and rely on other senses.
FACT: Sharks' eyes, which are equipped to distinguish colors, employ a lens up to seven times as powerful as a human's, and some shark species can detect a light that is as much as ten times dimmer than the dimmest light the average person can see.

MYTH: Most species of sharks are dangerous to people.
FACT: According to the International Shark Attack Files, of shark attacks recorded since the year 1580, only 10 of 400 species were involved in unprovoked fatal attacks. Bull, Tiger, White Sharks account for almost all attacks--and many of those attacks are assumed to be accidental.

MYTH: The Great White is a common shark found off beaches visited by humans.
FACT: Great Whites are relatively uncommon large predators that prefer cooler waters. In some parts of their range, great whites are close to being endangered.

MYTH: Whale sharks, the largest species of sharks, are voracious predators.
FACT: Whale sharks, which are the largest fish that ever lived, are plankton feeders like the great whales, thus the name.

MYTH: Sharks are very hard to kill.
FACT: The stress of being captured easily weakens a shark, so often many sharks are killed by hook-and-line fishermen and commercial netters.

MYTH: Sharks have tiny brains and are incapable of learning.
FACT: Sharks' relatively large and complex brains are comparable in size to those of supposedly more advanced animals like mammals and birds. Sharks also can be trained.

MYTH: Most sharks cruise at high speed when they swim.
FACT: Although some sharks can swim at bursts up to 25 mph, most sharks swim very slowly at cruising speeds around 5mph.

MYTH: Sharks are not found in freshwater.
FACT: A specialized osmoregulatory system enables the quite popular bull shark to handle dramatic changes in salinity -- from the fresh water of lakes and rivers to the highly salty waters of the ocean.

MYTH: Sharks are not discriminating eaters and scavenge the sea.
FACT: While this belief about shark eating habits is true of some species, it is not universally true. A tiger shark may gulp down anything it encounters, including shoes, license plates and canned goods (still in the can), but most species of sharks prefer to eat fish, crustaceans and mollusks.

MYTH: Sharks must roll over on their sides to bite.
FACT: Sharks can attack from whatever direction they please. They have a unique jaw design that allows them to protrude their jaw beyond their snouts, so they can even latch on to something directly in front of them.

MYTH: Sharks have no enemies.
FACT: The greatest enemy of sharks is man. He kills and hacks off the fins of 30 to 100 million sharks each year. That is, in three to five years fishers kill the equivalent of the entire population of the U.S. Humans are not natural predators of sharks, as we are terrestrial hunters and didn't really fish for sharks until we became civilized. Now we cut off fins and throw the living creature back to die on the bottom of the sea.

MYTH: Shark cartilage pills can prevent or even cure cancer.
FACT: While sharks and their close relatives have demonstrated a strong resistance to cancer, they are not entirely immune to it. There is no evidence that consuming shark cartilage will help prevent or cure this disease in humans. Dispelling this myth is crucial to help slow the demand for sharks by medical hoaxsters who are needlessly aiding in the decline of shark populations.

MYTH: There are too many sharks in the sea.
FACT: Anybody who does much fishing in the sea can attest that shark populations often seem to be on the decline. Over-fishing, water temperature changes and environmental pollution are all thought to be responsible for depleted shark populations.

MYTH: Sharks have been around forever and always will be.
FACT: Wishful thinking. Without human protection, conservation and ongoing advances in science, many species may become extinct. Luckily, many sportsmen these days are realizing this, and the trend to treat sharks as a nuisance is declining.

Source: www.sharktrust.org


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