Halle Berry in ‘Dark Tide’

Kate Mathieson, Halle Berry’s character in the maritime adventure film “Dark Tide,” is a so-called shark whisperer. She is the rare individual with the courage, stamina and intuition to communicate with great white sharks well enough to be able to touch their snouts and even safely swim beside them. The role isn’t a good fit for Ms. Berry, who, no matter what part she is playing, gives it a brittle defensive edge. The antithesis of a benign nature lover, Kate is an angry and easily provoked woman. Every disastrous move she makes is a hostile overreaction. Miscasting, however, isn’t the worst flaw in “Dark Tide,” directed by John Stockwell (“Into the Blue,” “Blue Crush”). Although it has a lot of gorgeous scenery — filming took place near Cape Town — the movie is swallowed whole not by the many great white sharks shown cruising through the deep but by its own underwater scenes. “Dark Tide” too quickly loses sight of the human drama and becomes a pseudodocumentary. Instead of an authoritative voice-over, characters who can hardly be distinguished from one another because of their goggles and scuba suits yell in semidarkness, their voices obscured by a pounding musical soundtrack. It is often impossible to figure out what’s going on. In the story, such as it is, Kate and her boyfriend, Jeffrey (Olivier Martinez), a cameraman, are filming a documentary about sharks when her colleague Themba (Sizwe Msufu), a safety diver who swims below her for her protection, is menaced by a shark. When Themba tries to divert the shark, it attacks and kills him, and Kate is racked with guilt for the rest of the movie. The story leaps ahead a year: Kate and Jeff have broken up, her seal-watching business has gone bust, and her boat is about to be taken by the bank. Jeff suddenly appears with an offer that could be her salvation. He has made a deal with William Brady (Ralph Brown), a wealthy British businessman who will pay her 100,000 euros for a chance to swim with a great white outside the safety cage. He has even bullied his reluctant son (Luke Tyler) into agreeing to join him. Kate is incensed and wants no part of it. But Jeff, who is still in love with her, persuades her to participate. So the dumb, foolhardy adventure proceeds. Brady is so overbearing and arrogant that you can hardly wait for his comeuppance. He is the most dislikable character aboard the boat; the only sympathetic passenger is the son, Luke. Mr. Martinez’s Jeff is an older version of the same oily flirt he played a decade ago in “Unfaithful.” Whatever chemistry Ms. Berry and Mr. Martinez are said to have off the screen, there is no sign of it in “Dark Tide.” With a running time of nearly two hours the film needs a major trim. The moment that Kate, in a fit of pique, decides to give Brady more than he bargained for by having the boat steered to a perilous place nicknamed Shark Alley, “Dark Tide” loses its perspective. Troubles mount. First the steering mechanism malfunctions. Then the anchor drags. Then all hell breaks loose as a squall hits. The ensuing chaos, much of it under water, reminded me of “The Perfect Storm” once the boat hit the tempest. All the camera technology in the world can’t sort out the human element in the rush of noise, bubbles and increasingly crimson water. Long before it ends “Dark Tide” capsizes and sinks with a sickening glug. “Dark Tide” is rated PG-13 (Parents strongly cautioned). It has some strong language.