Character mistake: During one of the shark scares at the beach, Chief Brody is running along the shoreline telling everyone to get out of the water. There are several frames where the Chief and a man with a moustache are at the water's edge. If you look closely you will notice that the man is smiling and laughing and other people laugh as well. (00:17:30)
Continuity mistake: After the Orca breaks down for good, Hooper goes into the shark cage to try to kill the shark. The shark proceeds to completely trash the bars on one of the sides. After Hooper escapes to the sea bottom, the shark is attacking the top of the cage, but the bars are now intact. [Extra info: The scene with the bars intact actually shows a very real shark that got caught in the line(s) holding the intact cage. When they raised the cage it was still caught in the line(s). They inserted this footage after the scenes with Hooper and Bruce where the cage got trashed.] (01:55:20)
Revealing mistake: In the absolutely brilliant boat scene towards the end of the film, there is a medium shot of the rear of the boat when Jaws comes right out of the water. If you look carefully under the shark model as it leaves the water, you can see the mechanical wheel they used to maneuver the model.
Continuity mistake: After Hooper cuts open the Tiger shark, when he throws a license plate towards the Chief the area to Brody's left is clear, but in the shot facing Brody there are lines and equipment lying on the ground beside him, to his left. (00:44:10)
Continuity mistake: Check out the scene where the girl gets attacked at the start - keep your eye on the clouds and how they move around. (00:03:10)
Continuity mistake: When the Tiger shark is displayed on the docks, the blood stains in and around the mouth and its body, either change significantly between shots or completely disappear. (00:33:00)
Continuity mistake: At his home, after Brody uncorks the bottle of wine he begins to peel the top label. In the following shots the top label changes, as well as the position of his hands, depending on camera angle as Hooper and Brody speak. (00:42:45)
Continuity mistake: While Brody watches the woman in the water, before Alex is attacked, there is a blue and yellow raft in the cabana behind him. In the close-up of his face, just before Harry's black capped head pops out of the water, the raft is gone. Then when Ellen massages Brody's neck the raft is back. The cooler and other assorted items change position between shots as well. (00:15:00)
Continuity mistake: When the man swims away from the 'shark fin' towards the family, in the shot from behind he swims between the older girl and young boy. However, in the next shot facing him he swims between the older and younger girls, causing the raft to tip. (00:59:10)
Continuity mistake: When Michael walks into the kitchen, he holds up his bloody hand and exclaims, "I got hit by a vampire!" In the next wideshot the blood on his raised palm differs. (00:06:00)
Revealing mistake: The ropes from the two barrels attached to 'Bruce' the shark are tied to the stern cleats, but then Bruce pulls on the ropes and starts to drag the boat sideways and nearly submerges the stern of the boat. As the boat is being pulled sideways by the ropes, they are both shown to have quite a bit of looseness, or slack in them. How can the boat be pulled like that if the ropes are not taut? (01:44:05)
Audio problem: When the old fisherman yells at his friend to swim faster and not to look back, his mouth movements aren't consistent with what he is saying. (00:25:55)
Other mistake: When the boy gets attacked on the lilo and everyone is told to get out the water, the group of boys are standing just in front of the pool of blood. The water is too shallow for a shark of that size to swim in without it being seen.
Visible crew/equipment: When the first barrel goes on and Quint is at the front saying "5° port now." When we see a close up of the barrel at the bottom right of the picture you can see the wake from the camera boat. The wake is going toward the shark and not away from it.
Revealing mistake: When Hooper is lowered in the cage you can see the oxygen bubbles rising to the surface from the underwater camera team.
Continuity mistake: After Quint trashes the CB radio, he runs to the pulpit with his harpoon gun. Between shots, he goes from leaning over the rail to standing inches away from it. (01:39:20)
Continuity mistake: On the Orca, after Brody's first attempt at a sheepshank, his hands grip the rope a couple of feet apart from one another. Between shots, his hands instantly come back together. (01:14:25)
Continuity mistake: Hooper runs into the very thick black-smoke filled cabin to go below deck, but in the next interior shot the entire cabin is bright and there is hardly any smoke anywhere. (01:48:40)
Continuity mistake: When the shark is harpooned to some rope, Brody & Hooper tie the rope to the stern cleats, causing the boat to be dragged backwards. Quint gets a machete to cut the rope to limit the boat's damage. At this point the sea is somewhat choppy. He throws the machete making it stick into the edge of the boat. The sea in the background is now completely calm. (01:44:25)
Continuity mistake: The word ORCA on the back of the boat continually changes from shot to shot varying from very rusty letters to shiny letters.
Answer: Possibly a scar from having his appendix removed, I've been told.
The appendix shot is Brody - he is feeling inferior as the other two share tales of the sea and the only scar he has is from his appendix being removed.