I may be an ocean advocate, but I have been terrified of sharks for my entire life. So, on a recent trip to Hawaii, I decided to finally confront my fear and signed up for an ecotourism shark cage dive. When I gathered the courage to lower myself into the cage, I immediately came face to face with a large Galapagos shark and was shocked by the sense that an intelligent being was looking back.

Its movements were smooth and graceful as it glided tranquilly past; its gray, sleek body standing in beautiful contrast against the cobalt blue water as I began a tremendous discovery process that would change my view on sharks forever. After such a personal experience, I came home needing to learn more about these animals I’d feared for my entire life. What I discovered was that not only were sharks in trouble, but surprisingly that their disappearance would deliver a serious cost to us as well.

Scientists estimate that 100 million sharks are killed by humans every year. What makes matters worse is that one-third of all threatened sharks are subjected to targeted fishing. This targeted fishing usually happens for their fins, which are used in shark fin soup, an Asian delicacy. In this process, fishermen catch sharks and cut off their fins, often while they are still alive. Afterward, they throw the animals back into the ocean, where they slowly succumb to their injuries. In fact, in addition to targeted fishing, habitat loss, persecution and climate change are all threats to sharks.

As a byproduct of all these activities, an estimated 25 percent of sharks and rays are now threatened with extinction, according to a recent scientific report. Like large predators on land, sharks affect all species below them by keeping populations and the food web in balance. Sharks are an essential player in the ocean ecosystem. Restoring drastically reduced populations could take decades for many shark species, because sharks generally grow slowly, mature late and produce few young over their long lifetimes.

The destruction of shark populations creates not just environmental degradation, but also economic cost. Shark ecotourism generates $314 million each year, a figure that is expected to rise to $780 million in the near future. Meanwhile, the landed value of global shark fisheries is estimated at $630 million per year, a figure that has been declining for a decade. In fact, according to a study by the University of Miami, a shark is worth about $73 a day alive, but a set of fins for shark fin soup is only worth an average one-time payout of $50.

In addition to the economic benefits though, shark ecotourism also allows people to form perceptions of sharks for themselves. By observing sharks in their natural habitat through scuba diving, snorkeling, cage diving and boat tours in a sustainable manner, people are able to see the natural beauty of these creatures. Of course, there are good and bad shark tourism operations, but if these companies genuinely work to minimize their impact on the environment, these dives can promote conservation through the educational experience.

“Only after seeing people’s reactions did I see what effect it had,” said Stefanie Brendl, owner of Hawaii Shark Encounters, a company that organizes shark diving tours. When people get in the cage, participants are generally fearful of sharks or just out looking for a thrill. When they get out, they have a newfound understanding and appreciation of sharks.

So many are afraid of sharks, when they should really be afraid of what will happen if they’re gone. If you’re wondering where you can start, I’d suggest participating in conservation-minded shark ecotourism by patronizing companies that minimize interference with the behavior of sharks. This way, you can discover these majestic sea animals for yourself like I did.

From there though, we need to take action. You should make a point to stop eating shark fin soup if you do, and restaurants should be encouraged to remove it from the menus to provide the pressure needed to halt this practice. People should also research the seafood that they eat and avoid eating fish from fisheries with a high rate of shark bycatch. Doing so may not solve the problem entirely, but it will significantly cut down on the threats to sharks.

The truth is it doesn’t matter if the context is environmental or economic; the world just can’t afford to lose 100 million sharks a year. It’s time to make a good investment: saving sharks.