Jogging on a local beach, I spot a knot of people at the water’s edge. A few feet away, in thigh-high waves, a man in a wetsuit holds a silver fish, wriggling in his hands. It seems  unremarkable, until I notice its teeth: row upon row, gleaming white and razor sharp. Out of its element, writhing with all its might, the young shark looks strangely vulnerable.  My first— and only—encounter with one of the most formidable predators on the planet makes me wonder:  Should we fear them—or fear for them?  The answer is both.