It may have happened to you. You’re out for a sail and you spot a fin in the water. Someone begins his best impression of the familiar pulsating cello line as another person jokes, “We gotta get a bigger boat,” and talk turns to the film whose release one weekend 38 years ago forever changed our nation’s relationship to sharks.

Now, after studying sharks and their conservation for more than two decades, I assert that these fascinating predators suffer from an identity crisis: Sharks are greatly maligned for their fierce reputation yet, in reality, are among the most vulnerable animals on the planet. Nearly four decades after the release of Jaws, it remains difficult to convince the average beach-goer and even some of my friends and relatives that sharks in fact have much more to fear from us than we do from them.

Yet it is true. Overfishing of sharks and their close relatives skates and rays across the globe has in recent decades led to sharp declines in shark numbers. Some species have been reduced by more than 80 percent. Much of that reduction is tied to the international trade in shark fins. The fins of as many as 70 million sharks end up in the coveted Asian delicacy shark fin soup each year. At the same time, some of the most heavily fished sharks and closely related skates and rays are prized primarily for their meat.