Continuity mistake: When Brody yells for everyone to get out of the water after Alex's attack, the position of all the adults and children as they run differ greatly depending on camera angle, regardless of the ensuing mayhem. (00:17:25)
Continuity mistake: After Alex's attack, there is a close-up of the $3,000 reward sign pinned to the board, as the woman complains, "We won't have any of our regular customers..." in the next shot as she continues to say, "We don't even know that there's a shark around here..." the reward sign on the board has different handwriting and is positioned differently on the board. (00:18:10)
Continuity mistake: As the townspeople make their way into council chambers, we can see Mrs. Taft talking to Chief Brody before she takes a seat. Between frames, her purse strap removes itself from her left shoulder. (00:19:00)
Continuity mistake: When the camera is zooming in on Quint as he gives his speech at the town meeting, there is a woman in black and another in blue, seated in the room. In the next shot of people in the room listening to Quint, the woman in blue is in the foreground, but the woman in black who was sitting right next to her, has vanished. (00:20:00 - 00:20:35)
Continuity mistake: In the council chambers, after the Mayor says, "Only 24 hrs," as the people argue in the wideshot a particular area of the chalkboard is visible behind them and it is blank. In the very next close-up Quint, who was not in the previous shot, scrapes the board with his nails, which now shows the large doodle of the shark, that should have also been visible in the previous shot, but was not. (00:20:30)
Continuity mistake: After Quint scrapes the chalkboard with his nails, in a close-up when he says, "Gonna stay alive and ante up, or gonna play it cheap," the papers pinned to the bulletin board are visible in the room behind him, as well as the chair, etc. In Quint's next close-up, the papers differ with additional pink and blue sheets and the chair is now at the other end of the board. (00:21:20)
Continuity mistake: Throughout Quint's speech in council chambers, the door behind Brody continually opens and closes in alternating shots. (00:21:25)
Continuity mistake: While Quint makes his offer at the town meeting, when he says, "I don't want no volunteers, no mates...," the chalkboard is beside him in this close-up. The doodle of the shark on the board, and the actual wood grain of the chalkboard frame all differ from the previous shots. (00:21:40)
Continuity mistake: Just after Brody flips through the pages of the graphic shark book, Ellen tells him that Michael is sitting in his boat and outside their window the sun is just above the horizon, showing a pretty sunset. Then when Brody rushes to the door to shout for Michael to get out of the boat, amusingly enough the sun is now much, much higher in the sky. (00:23:00)
Continuity mistake: When Brody jumps from his seat to get Michael out of the sailboat, he lifts Ellen by her arms. But then, one shot later, he's lifting her by the hips instead. (00:23:35)
Continuity mistake: When the two old fishermen are fishing for the shark from the pier, the shark takes the bait and you can see the chain getting pulled into the sea. In the next shot you can still hear the chain being pulled into the sea but if you look on the pier, you can't see any chain being dragged in and the wooden post that the chain is secured to changes into a different position. (00:25:20)
Continuity mistake: As Brody flips through his shark book, he pauses to look at a photo of two fishermen and their catch. The photo is on the right page, but in the previous shot where we see Brody stop flipping through, there was no picture on the right page as seen in a reflection on his glasses, just words. (00:25:30)
Continuity mistake: When the shark swims away with the roast bait, a dramatic close-up of the quickly unfurling thick link chain lying on the dock is shown beside the trashcan. The unmoving end of the chain lies behind, to the left of the trashcan and the end being pulled is on the right, with the slack at the center. Now when the chain is pulled taught in the following shots, the trashcan should have flipped over, if the slack chain was indeed where it was shown to be in the close-up. In the wide shots the trashcan sits on the left at the center of the dock, but the chain being pulled is attached to the piling at the right corner end of the dock. (00:26:15)
Continuity mistake: On the dock, Charlie and Denherder wrap a link chain around the corner piling, which is yanked when the shark takes the roast bait. In the close-up the chain is pulled taught from the front and breaks free, but in the next wide shot the chain is slack and being pulled from behind the links around the piling. (00:26:25)
Continuity mistake: The chunk of dock that floats in the water, as the shark pulls it, differs from the piece of dock that broke off in the previous shots. (00:26:30)
Continuity mistake: At the harbor, just as Brody asks, "Help me get those guys out of the boat, will you?" in the wideshot there are five men standing on the dock and three standing in the boat. Then in the next close-up, there are four on the dock and four in the boat. The one in a black/white check shirt is now at the end of the dock and the one in a black rain slicker, that was standing on the dock, is now suddenly standing in the boat below, at its stern. (00:28:45)
Continuity mistake: When Chief Brody asks, "How many guys you gonna put on that boat?" he stands between two adjacent pilings. Hooper then stands beside the same two pilings in the following wide shots. However, in the close-up when Hooper asks about a good restaurant on the island, he is at the center of the shot standing beside only one lone piling. Richard Dreyfus' beard is also fuller in the close-up, than in the wide shots. (00:28:50)
Continuity mistake: In one of Richard Dreyfus' first scenes, Brody asks him to help with the group of men crowding into a small boat. Hooper says that the officer wants him to tell them that they're overcrowding the boat. They show the men climbing in and there's a guy in a blue jacket climbing down the ladder into the boat. He waves his arm and says "what do you care?" They then show Hooper asking if they know a good restaurant or hotel on the island. When they show the men again, uttering the line "Yeah, walk straight ahead," the man in the blue jacket is on the deck again and is again descending down the ladder. (00:29:00)
Continuity mistake: When Hooper tries asking the fishermen about a restaurant or hotel on the island, he makes a motion with his right hand. But between shots, his hand grabs onto the wood piling. (00:29:10)
Continuity mistake: In the medical examiner's room, before Hooper splashes water over his face, he rolls up his left sleeve just a bit. His wristwatch is in view, but between shots the watch tucks itself away under his sleeve. (00:32:40)
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.