“You're told your whole life, since you're a kid, sharks are dangerous. You're warned about venturing too far into the ocean, but then finally you're underwater, and you see the thing you were taught your whole life to fear, and it's perfect, and it doesn't want to hurt you, and it's the most beautiful thing you've ever seen … and your whole world changes.”

– Rob Stewart in his documentary “Sharkwater”

Ironically, “Jaws” was what got me into sharks. Last October, my teacher used the movie, based on the book by Peter Benchley, to teach us about literary elements in a novel. She talked about it so much that I finally decided to read the book. It immediately became my favorite, and I raced through the rest of Benchley's books.

I became obsessed with sharks, recording TV shows, checking out piles of books, and spending hours reading about sharks online. Eventually I became a kind of walking shark encyclopedia, correcting BBC and Discovery Channel. I would sit next to the underwater viewing area at Shark Lagoon in the Aquarium of the Pacific, watching the sharks circle the tank, irked each time someone called one of the blacktips a great white (which have only successfully been held in captivity by the Monterey Bay Aquarium), or mistook the male sandtiger hovering in the center of the tank for a mako.

I know that some readers will recall the iconic fin knifing through the scenes in “Jaws,” or one-armed surfer Bethany Hamilton, and think, Sharks eat people. But the truth is, these stereotypes are about as true as Nazi-UFO conspiracy theories. After “Jaws” became an international hit, Benchley felt guilty. In the years following Jaws-mania, he repeatedly admitted that almost all the behaviors exhibited by the shark in his story were incorrect or misinterpreted, and that he would never have written it with the knowledge of sharks we have today.

And while the movie “Soul Surfer” is based on the true story of Hamilton's shark attack, incidents like this are always accidents. You wouldn't hang out next to a pride of lions wearing a zebra costume, but that's what people do with sharks every day. A surfer on his board looks a lot like a seal, one of the shark's favorite foods.

It's pretty amazing how few people are attacked by sharks when we look so much like their natural prey. Out of the nearly seven billion people on the planet, about five are killed by sharks each year. You are more likely to be killed by toasters (791 people per year), chairs (592), coconuts (150), lightning (60), dogs (45), or vending machines (20). Forty times more people will be hospitalized for injuries involving Christmas tree ornaments than shark attacks this year in the U.S. alone!

Perhaps you've have heard of “The Summer of the Shark.” In the summer of 2001, the media went on a frenzy about sharks. A pilot flying over the Gulf of Mexico saw a large school of sharks. Then a few people got attacked by sharks. Soon the media was even telling people Cuba was sending killer sharks to get even with America. Then 9/11 happened, and everyone realized the sharks weren't such a big problem after all.

As upsetting as this was to me, what disturbed me even more was the massacre of the animals. I asked my teacher if the documentary “Shark­water” could be shown in our class, and being a shark fanatic herself, she agreed. The documentary follows activist Rob Stewart as he fights to save sharks. Stewart shows how the growing hunger for shark fins in Asia leads to cruel and illegal activities.

I stared blankly at the ground during the scenes in the documentary that showed sharks having their fins hacked off, and, still alive, being thrown back into the sea to sink and die. As many as 100 million sharks are killed each year, primarily for their fins. This is three sharks per second, or about 1,100 an hour. At this rate, scientists estimate that most species of sharks will be extinct in 10 years. As of now, most species are almost 90 percent gone, and some are functionally extinct – meaning that while the species isn't entirely gone, there are so few remaining there is almost no chance of return. The great white shark, at 3,500, is more endangered than tigers, polar bears, and snow leopards. New Guinea River and Bizant River sharks are now under 250 individuals. Sharks are perhaps the most endangered group of species on the planet.

But why should anyone care when there are cuter, cuddlier animals to save? We see posters and TV programs about saving pandas and polar bears, but most people don't even know that sharks are endangered, let alone the alarming rate they are being killed. Without sharks, most of Earth's oxygen will disappear, leading to the world's sixth mass extinction.

See, sharks are the top dogs of the ocean. They are the apex predators of Earth's most important environment, the ocean. Sharks are the guardians of the ocean's phytoplankton, in much the same way that wolves are the guardians of the tundra. Sharks eat smaller creatures below them in the food chain. If these populations are not kept in check, they will rapidly consume the phytoplankton, which produces 70 percent of the world's oxygen. When the sharks die, the plankton dies, and when the plankton dies, we all die.

If sharks are 90 percent gone, then why aren't there drastic changes on Earth? The answer is simple – there are. Phytoplankton not only produce oxygen, they also absorb carbon dioxide, a greenhouse gas. So the decline in sharks is one of the causes of global warming. And around the world there is an epidemic of intermediate predators multiplying exponentially without their top predator. The Sea of Cortez used to be full of gargantuan schools of hammerhead sharks. But because of the demand for shark fin soup, fisherman finned sharks until the sea was literally red with blood. Now it is extremely rare to find sharks in the Sea of Cortez, and so Humboldt squid populations have boomed. The squid eat much of the small fish that sea lions like to catch, and now the Sea of Cortez's sea lions are starving to death. In Chesapeake Bay, without the coastal sharks to prey on them, cownose ray populations have exploded to 40 million individuals, and they are destroying the scallop beds.

My classmates were shocked by “Sharkwater.” During the discussion afterwards, one student suggested we start a club to raise money for Shark Savers, a shark-conservation group. My teacher and I arranged a trip to visit Assemblyman Mike Gatto, to encourage him to support AB 376, a bill that would ban the possession of shark fins in California, which is second to China in shark-fin consumption. Over summer vacation we visited Senator Liu, who also voted in favor of 376. Finally Governor Jerry Brown signed the bill, making it law. However, along the way it was changed so that restaurants can still use fins until 2013.

The next school year I created the Shark Club to raise money and plan activities like selling T-shirts, making posters, and perhaps have the school watch “Sharkwater.” I try to support shark conservation in any way I can, by attending rallies and meetings with spokespeople from Sea Shepherd, and by teaching my friends and classmates about sharks. I'm also trying to get a shark-conservation group to lecture at my dive shop. Here are some ways you can help sharks:

• Don't eat shark meat or shark-fin soup.

• When you buy fish, make sure it isn't shark under a different name. Rock salmon, for example, is actually another name for a kind of dogfish. Shark is often included in fish n' chips and fish patties like pollock.

• Boycott any seafood restaurants that sell shark or ray products, and tell them why they shouldn't buy shark products.

• Today's fishing methods are extremely damaging to the ocean ecosystem, and scientists predict fisheries will crash by around 2050. Fishing nets kill thousands of sharks, dolphins, turtles, and whales each year. Many of these nets are used to fish for tuna, which like sharks, are extremely endangered. By giving up seafood, we can help stop animals dying as bycatch, and preserve the ocean's fish.

• Educate others about sharks and how endangered they are.

• Don't buy cosmetics with squalene, a substance made from shark cartilage.

• Donate money to conservation groups such as Shark Savers, Sea Shepherd, and Shark Angels. Even $5 helps!

• I highly recommend you watch “Sharkwater.”