Great White Shark - PG005

The Great White Shark (Carcharodon carcharias)

Sharks are a highly successful and diverse group of fish that have roamed the earth for over 350 million years. They have adapted to virtually every ocean habitat, from shallow coastal waters too open sea, and from the tropics to the poles.

Often referred to as primitive, sharks actually have highly developed senses to aid in detecting prey. Their senses of smell and hearing are acute. Vision is usually very good, and their lateral line system enables them to detect small movements in the water around them. Small pores on the snout are capable of detecting the weak electric fields generated by living organisms, and may help migrating sharks to navigate by orientation to the earth's magnetic field.

One of the most notoriously famous sharks is the Great White. Normally uncommon, it can be found in almost all oceans, but tends to prefer coastal area where there is a sizable marine mammal population. Young whites eat primarily fish, but adults prefer to eat seals, sea lions, and the carcasses of dead whales. Human swimmers, skin divers and surfers are occasionally attacked in areas where great whites are hunting, but such encounters are very rare.

While only a handful of people worldwide die each year from shark attack, millions of sharks die each year at the hands of humans. Their meat has become a popular food item in the last decade, and their finds are sought-after ingredients for soup. Their teeth and jaws often end up in the souvenir trade, and shark cartilage has been touted for its supposed medicinal abilities. While shark cartilage is a valuable ingredient in creating artificial skin for burn victims, its usefulness as a cure for cancer is unproven at best.

Shark's life histories make them very vulnerable to overfishing. Many take up to 15 years to reach maturity. Many sharks have very few young at a time, and some give birth only once every few years. As a result of fishing pressure, populations of several sharks have been reduced by 60% to 80% over the past decade. In response, the United States has placed limits on the number of sharks taken by commercial and recreation fishermen. A federal ban is in effect on fishing for certain species, including the great white. While these protective measures are promising, sharks worldwide are still caught in fishing gear intended for other species. Other threats to survival include entrapment in discarded and abandoned fishing gear, pollution, habitat destruction in shark nursery areas.