Actors Adrian Grenier and Leonardo DiCaprio are among the executive producers of filmmaker Joshua Zeman's nature documentary, which explores a rather melancholy oceanographic enigma. Since 1989, deep-sea microphones (originally meant to detect Cold War submarine maneuvers) detected a whale's song at the 52 megahertz frequency—a mating call that no other whale had been producing. Ultimately the lone whale—named "52"—has been heard again and again—but never sighted.
Is this mammal a new species, or the last of an old-line, or some fin-whale hybrid or freak of nature? The plaintive idea of a solitary whale singing all alone has since fired the imaginations of researchers and laypeople alike.
With a science crew and a vessel off the California Coast, Zeman, who claims a boyhood fascination with ocean life, has funding for just a few days at sea to locate 52—who actually does travel and interact with pods, despite the creature's reputed social isolation—and, ideally, plant a tracking device and perhaps even a remote camera in 52's hide (off-screen involvement of screen stars DiCaprio and Grenier go unmentioned).
Because a boat crisscrossing the waves at length is not necessarily an exciting narrative device, the film then backs into the dismal history of man's interaction with whales, the heartless carnage inflicted by the commercial whaling industry, and the toll that continues to be taken by cetacean/freighter collisions. There is an assertion that only science's discovery of whalesong (commemorated here in a Partridge Family episode) saved whales from being hunted to extinction.
The focus then returns to Zeman's quest, echoing Ahab's pursuit of Moby Dick but far nobler. It ends in an inconclusive manner - keep watching through the end credits, please—yet this is a finale that may satisfy eco-sentimentalists that there is hope, yet so much more needs to be done. The recommended title should find a safe harbor on environmental and science-oriented shelves. Aud: H, C, P.