Are sharks endangered?

Many species of sharks are endangered, but the most affected is the great white shark.  The greatest threat to sharks is that of being hunted by humans for their fins and oil.  Shark oil is rich in vitamin A and is used in medicine and cosmetics.  Shark finning is commonly done as shark fins are considered a delicacy, especially in Asian countries.  Sadly, when a shark is finned it is thrown back into the water while it is still alive and since it can no longer swim it sinks to the bottom where it is eaten alive or bleeds to death.  Another threat to sharks is what is known as by-catch which occurs when sharks get caught in commercial fishing nets;  thousands of sharks die each year by getting caught in nets that are designed to keep them away from swimming areas.