14 January 2009

Threatened Sharks

Scientists say sharks have lived in the world's oceans for millions of years. But their survival now is threatened. People have feared the fish because of its sharp teeth and aggressive actions.

Now it seems that sharks need to protection from people. Scientists say people are killing sharks in the Atlantic Ocean and Gulf Mexico faster than the sharks can reproduce. They believe that without extreme protection measures some kinds of sharks will disappear.

Experts say fishermen are catching too many sharks. The main increase in demand is in Asia for shark fins. People use the fins to make a popular kind of soup. American fisherman also have begun hunting sharks for sport.

Scientists say sharks are important to the environment of the oceans. Sharks eat many other fish. Without sharks, some fish populations would quickly increase, This could damage the balance of life in the oceans.

Sharks also are important for medical reasons. Doctors have used the corneas from shark's eyes for experimental human eyes operations. They use sharks' soft bony areas called cartilage to make skin for burn victims. Shark liver oil is used in medical treatments.

For several years, scientists have been studying the shark's powerful immune system. They want to find out why sharks do not seem to develop cancer. They want to know why sharks rarely are sick. And how their wounds heal so quickly.

Scientists say saving endangered sharks is difficult because they reproduce and develop so slowly. Many kinds of sharks are not able to reproduce until they are 25 years old. Some reproduce only every two years. And then they give birth to fewer than ten young sharks.

The United States approved federal shark protection plan. It bans killing sharks only for their fins. It also order limits on catching 39 kinds of sharks. The limits are in effect in waters within 200 miles from the Atlantic and Gulf coasts of the United States in the Carribean Sea.




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