Walker and Alba also had close encounters with reef sharks in the movie. Walker’s character, among other things, is swarmed by feeding reef sharks as he tries to get into skin-diving gear while bobbing in the water. “I had seen sharks while diving in spots like Fiji, Hawaii and Costa Rica,” says Walker. “But I had never seen so many in one place. They’re wild animals and you have to be leery of them, even when you have safety divers around you. In this scene I am treading water and these sharks are boiling all around me. They bump you a lot, so you can only kick them off the best you can. I must have had 30 sharks around me. It was very intense.”
Alba's character, Sam, is a professional shark handler at the Atlantis Resort in Nassau, so the actress spent a great deal of time learning how to deal with sharks by actually feeding them on camera in several scenes. She shot a sequence in the Atlantis' shark pool in which she hand feeds scores of nurse sharks, who are generally not dangerous biters. Still, Alba paid close attention to the instructions from the resort's shark handlers so she would be sure to complete her scenes with all her fingers and toes intact. "You have to be aware of your hands and feet," she says, "and pray the sharks don't mistake you for a fish. I'm the one in their territory and they are going to do what they want to do. What I learned is that the sharks don't care for the taste of humans. We aren't fish, and that's what they want to eat. They're incredible creatures."
There are also more dangerous scenes in the film involving a tiger shark in which the actors were working with the real thing. The sharks used in the film were wild and could not be trained, so the shark used onscreen was one that was found at that day’s location. To ensure tiger sharks showed up when needed, Cove veteran shark wrangler, Alex Edlin, assembled a tiger shark hunting team that would get up at dawn to check the lines for any large shark that may have been trapped overnight. The team would then lift it into a box on their boat and transfer it to a special shark pen. (All the sharks were later set free).
However, the first large tiger shark caught had other ideas, according to Cove. “One morning we found that we had a 10-footer and we got all excited,” he says. “It was splashing all over and as we tried to pull it into the boat, it got its teeth around a steel cable, biting right through it. It was devastating since we’d been up all night trying to catch him. It took another few weeks before we got another one that size.”
For Stockwell, using real sharks enhanced the feeling of realism he was seeking. “We got some incredible footage with all the actors and the sharks,” he says. “I want people to understand that these sharks are real. I think the film benefits from the fact that we didn’t rely on digitalized animation.”
To support the mammoth production above and below the water, an armada of boats had to be secured and kept at the ready throughout the shooting. Marine coordinator Ricou Browning (Bad Boys 2) collected more than 50 vessels, ranging from a 145-foot barge to a fleet of small inflatable Zodiacs. The main shooting vessel was a camera barge that Browning built and designed to meet the need of Into the Blue’s director of photography, Shane Hurlbut (Mr. 3000, Crazy/Beautiful). The shooting barge, named the Corinthian, carried a versatile long-armed crane that was used for shots in and on the surface of the water as well as for shooting scenes on the other boats.