In aid of dolphins. By CALEB STARRENBURG.

WITH A SPY-THRILLER intellect and activist spirit, The Cove is an utterly compelling exploration of the dolphin trade, and the efforts of one passionate individual to tear it down. That one man is Richard O’Barry, the former dolphin trainer for iconic 1960s television show Flipper, who blames himself for fuelling the world’s obsession with SeaWorld-type parks. Ever since the show’s aquatic star died – O’Barry contends she committed suicide – he’s devoted himself to freeing dolphins held in captivity.

For O’Barry – an old school campaigner who’s willing to put more on the line than an armband – the frontline in the global trade is a secretive cove in Taiji, Japan. Every season thousands of dolphins swim past the coastal city and are corralled into an inlet. Some are sold to aquaria – the right dolphin can fetch hundreds of thousands of dollars. The majority, however, are herded away from prying eyes to be killed for meat.

O’Barry has been trying for years to halt activities at Taiji, without success. He believes if ordinary Japanese, and the world, could just see what goes on there, they’d put a stop to it. Unfortunately the cove is heavily guarded and the police tail his every move. Finally he enlists the aid of Louis Psihoyos, National Geographic photographer and the film’s director, who assembles his own team of eco-infiltrators. Using a combination of spy equipment and cinema special effects gear, Psihoyos’s team conspire to capture on celluloid what has never been seen by outsiders. In a series of white-knuckle will-they-won’t-they be caught operations we watch our crusaders slip into the Taiji’s cove under cover of darkness to plant surveillance devices. What they find is galling.

The film is pitched at exactly the right level; not the anti-Japanese tract it could easily have become, but instead as a health warning. Dolphins, it turns out, are swimming toxic dumps. The level of mercury in dolphin meat is above acceptable limits, and eating it has the potential to cause serious birth defects. The documentary explains dolphin isn’t a wildly popular culinary treat in Japan – so is often disguised as other fish (although the extent to which this is happening isn’t made clear).

The film also suggests, perhaps too gently, that we’re all complicit. The industrial pollution created by the western world contributes to the poison that fish are now feeding on. And if it wasn’t for our love of circus-trick performing sea creatures, the global demand for captive dolphins wouldn’t exist (in a question and answer session after the film, Psihoyos suggested we give aquaria parks a wide berth).

There’s also an examination of the geopolitics of International Whaling Convention, in which it’s alleged the votes of poorer nations are bought. The film visits a multi-million dollar fish factory built for a Caribbean country in exchange for their pro-whaling support. Today it’s used to store chickens.

The Cove is occasionally remiss in its information. There’s a lack of hard statistics on dolphin populations, or intelligent opposing points of view (the so-called expert African ambassadors who’ve never seen actual dolphins hardly count). However, like the best activist documentaries The Cove engages the heart and the mind – it dares you to find out more and formulate your own opinions. And if what you discover is unpalatable, it asks you to get involved.