Sharkwater Productions. 89 minutes.

Like most predators, sharks get a bad rap as fearsome man-eaters. Yet, as filmmaker Rob Stewart explains with surfer-boy sincerity in Sharkwater, “They’re so afraid of us.” And with good reason—over the past 50 years, their population has dropped 90 percent due to longline fishing, Jaws-inspired trophy hunting, and the booming popularity of shark fin soup in East Asia. Stewart’s debut film provides a visually stunning image makeover for the misunderstood and threatened fish. “You’re told your whole life since you’re a kid that sharks are dangerous,” he narrates as we watch him cradle an accommodating, if not exactly cuddly, man-sized shark on the ocean floor, “but then finally you’re underwater…and it doesn’t want to hurt you.”

Though Stewart’s communion with sharks is reminiscent of “Grizzly Man” Timothy Treadwell’s fatal attraction to bears, his quest to save his favorite animal is grounded in the real world. He joins the crew of the Ocean Warrior, captained by environmental buccaneer Paul Watson, who’s known for ramming rogue whalers and other high-seas depredators. Off the coast of Costa Rica, the ship skirmishes with shark-poaching fishermen. On shore, Stewart discovers a massive illegal shark-processing business, filming thousands of fins awaiting shipment to China. (See “The Last Empire“) The story of Stewart’s crusade is interrupted by musical interludes (is that Enya playing?) meant to convince us of sharks’ soulfulness. Fortunately, Stewart’s astounding underwater cinematography makes up for such cringeworthy moments. A mesmerizing shot of schooling hammerheads subtly makes the case that you don’t have to love sharks to understand that their extinction would be a profound loss.