Continuity mistake: When Ben takes the photograph of the shark tooth to have it analyzed, he hold the tooth as he uses his digital camera. The camera is not connected to his computer, but the picture appears anyway. Also, Ben's fingers are not holding the tooth and the photo doesn't have a background.
Continuity mistake: After the boat sinks, the shark opens its mouth to eat two floating men. Their heads have been pasted in the middle of the mouth footage, but their bodies have suddenly disappeared, together with the floating device they held onto. Furthermore, they don't shout, cry, move, or show any reaction whatsoever.
Continuity mistake: The lifeguard runs to the shore telling people to get out of the water, and passes by some people on the beach. There's a two-second-long shot of the swimmers, and suddenly the previous scene is repeated for no reason at all. The lifeguard is away from the shore running towards the water again, and all the people on the beach have vanished.
Continuity mistake: On the boat, the crew is filming the shark approaching. When it swims, bait suddenly appears hanging from the air, which changes to a humongous piece of bait half a second later, together with the climate, that swaps to cloudy, and then in a change of angle the bait is gone and it's sunny again.
Continuity mistake: Before the cameraman is about to be attacked by the shark, he says he's filmed a great scene and gives a high five to Cat two times. The second one, she lifts her right arm but immediately the shot cuts to a close-up where she has her arm down, yet the sound of hands touching is heard.