A gripping thriller about dolphin trafficking, The Cove is an eco-mentary that's as passionate and persuasive an argument for change as An Inconvenient Truth.

And it's a chronicle of a covert operation that reveals an ugly practice that takes place in one of the planet's most beautiful spots, the fishing village of Taiji, Japan.

It all started with Flipper. In much the same way that Lassie cultivated a collie craze, the popular 1960s television show about a playful and wise bottlenose dolphin created a mania for the marine mammals. So much so that around the globe, trained bottlenoses are the chief attractions at aquariums and a magnet for exclusive resorts that offer a "swim with the dolphins" program. Chirruping and smiling, dolphins generate billion-dollar revenues. Taiji supplies most of the world's bottlenoses, which fetch up to $150,000 per.

Does this amount to a kind of marine slavery? That's certainly the thinking of Ric O'Barry, the guy who captured and trained the five bottlenoses used on television's Flipper. After seeing what Flipper wrought, O'Barry dedicated himself to freeing captive dolphins, an advocacy that has earned him numerous arrests and a rep in some quarters as a whack job.

Such is the eloquence of Louie Psihoyos' film that as The Cove progresses, the wild-eyed O'Barry begins to look less like a zealot than a rational man who sees the global picture.

The fishermen of Taiji - a town that looks like a marine theme park - interfere with dolphin migratory routes by disorienting the acoustically sensitive creatures with percussive sounds. Then the fishermen corral the mammals, separating parents from calves, and sell the choicest specimens to the highest bidder.

It's what happens to the dolphins that don't go on to be the rock stars of aquatic parks that most concerns Psihoyos, a National Geographic photographer and amateur scuba diver who conveys his alarm that his favorite reefs have been overfished and degraded. When O'Barry alerts Psihoyos that there looks to be a major cover-up in Taiji, where the city fathers have cordoned off a naturally fortified cove with barbed wire and aggressive watchmen, it pricks the filmmaker's curiosity.

Psihoyos assembles an elite squad, a cross between Navy SEALs and Ocean's 11, to expose the secret of the cove. His team includes free divers, audio engineers, risk junkies, and FX specialists who create fake rocks in which to embed digital microphones and camera. The stupendously beautiful, and shocking, footage they capture is the result not of an artist's eye and ear, but of neutral surveillance equipment artfully deployed.

What Team Psihoyos uncovers will not be revealed here. But it will incite rage, excite activism, conceivably rewrite international fishing policy, and almost certainly earn an Oscar nomination for best documentary. Those faint of heart (and under 14) probably should not see The Cove. But everybody else should. Apart from The Hurt Locker, you won't see a better thriller this year.EndText

Contact movie critic Carrie Rickey at 215-854-5402 or crickey@phillynews.com. Read her blog, "Flickgrrl," at http://www.philly.com/philly/blogs/flickgrrl/