In his upcoming PBS special "Sharks at Risk," Jean-Michel Cousteau, son of the legendary explorer Jacques Cousteau, says more must be done to protect the declining shark population. But convincing people to protect sharks -- an animal that most fear -- won't be easy.
Out of 400 species of shark, "there are only five or six species that cause problems, and they give the rest a bad name," Cousteau said.
But even with their bad name, we still need sharks. Every year, 100 million sharks are killed by fisherman -- either caught accidentally or fished for food, according to Cousteau.
"Sharks are scavengers," Cousteau said. "They keep the ocean clean of the sick, wounded, unhealthy. It's an ongoing job they perform to keep our life-support system healthy. Unfortunately, there are a few species that have been so harvested that it's changing the ecosystem of the ocean."
At one point in the film, Cousteau goes for a ride on a great white shark by grabbing on to its fin, under the supervision of Andre Hartmann, a commercial fisherman turned shark-tour guide.
"Well, first of all, I want to state the fact that I did it, I will not do it again, and I strongly recommend that nobody else does it," Cousteau said. "But I wanted to show that these animals are not the nasty maneaters that everybody believes they are. In fact, they are extremely timid."
Cousteau said he took precautions for the shark ride by making sure there was no food in the water and that no one was spearfishing or fishing. He also said getting bitten by a shark is less dangerous than eating shark fin -- a popular delicacy in Asia -- because of the high mercury level.
"In the long run, my free dive with a great white shark was probably safer than eating shark fin soup," Cousteau said.
Marine biologist Holly Lohuis traveled with Cousteau to make the film and said one of her most memorable moments occurred during a 200-foot dive when she had the chance to swim with a swarm of gray sharks on a reef in French Polynesia.
"It is a threatened species," she said, "but to see that many of them there gives you some hope and an incredible amount of respect for these animals."