Why Would It Be Bad if Sharks Became Extinct?

Sharks as Controllers

• Sharks tend to prey on certain types of items and control their numbers. Great whites prefer tuna and seals while tiger sharks will eat just about anything. The whale shark is true to its name and eats plankton or tiny fish. If all sharks were to go extinct, their prey species would overrun the oceans. Many of those prey items would adversely effect the environment, causing other species to leave the area. This, in turn, would cause the species that ate them to leave the area until nothing was left for even humans to hunt. One example of this has happened already with the sea otter.

Sharks as Indicators

• Sharks are very diverse and inhabit every ocean on the planet (even the poles). Because of this diversity, they are what scientists label "indicators:" a species of animal in an environment whose presence or absence indicates how well that environment is doing. A lack of sharks says that the environment in the area is not doing well at all; there is nothing for them to eat, and the habitat may be sickly. They help maintain reef systems, for instance.

Sharks and the Economy

• Sharks as controlling creatures has an indirect impact on the human economy. The loss of sharks has already adversely affected reef systems, which in turn has caused considerable loss to commercial fisheries. A specific example is the removal of clam chowder from many American menus. Without sharks, rays have taken over to eat all the shellfish, including the clam. On the positive side, sharks can also bring in millions for ecotourism -- one whale shark alone can add $2 million to the Belize economy through wildlife tours, diving tours, and research.

Threats to Sharks

• Some of the major threats to sharks include commercial fishing, finning, trophy hunting, and habitat loss. Commercial fishing practices vary, but some of the biggest offenders are long-lines, gill nets, purse seines, and bottom trawlers. What the fishermen can't use or don't like is tossed over the side (usually dying or dead). Finning is the practice of catching sharks only to remove their fins, which are considered a delicacy in some parts of the world. The rest of the shark is then thrown overboard. There is also fishing for sharks in order to keep their jaws as trophies. Habitat loss happens due to pollution, but also due to over-fishing or otherwise destroying the ecosystem of the ocean.