Continuity mistake: When Quint slides down the deck towards the shark, there is a shot that shows Brody's legs sliding right behind Quint. However, Brody is still back up in the cabin in the next shot.
Revealing mistake: When Quint begins singing 'Ladies of Spain' while Bruce is chasing the Orca into the shallows, he turns slightly to his left and looks over his shoulder. When he does, you can see that the barrels are actually being towed by the Orca, due to the wake of the line doing the towing.
Revealing mistake: When the boy is attacked at the beach a man says "did you see that?" The woman behind him wearing the hat sits up with everyone else then looks directly at the camera and smiles instead of looking at the attack.
Revealing mistake: When Brody is stabbing Jaws at the end with the harpoon, you can see air bubbles under the rubber skin on top of Jaw's head - air bubbles or the blood bags.
Continuity mistake: When the barrel comes over the top of the boat Brody ducks to his left and it just misses him - in the next shot Quint is standing immediately to his right, so he should have been hit by the barrel, knocked out or even killed.
Revealing mistake: Just after the first shark attack, Chief Brody and his deputy discover the beached remains of the nude swimmer. As Chief Brody hesitantly approaches the grisly scene, the camera cuts to a close-up of a mutilated female arm and other viscera, covered with a creeping cluster of small saltwater crabs. Inexplicably, a single crab falls out of thin air on the right side of the screen to join the others. A moment later, Chief Brody arrives at the scene, in the background. Obviously, a film crew member dumped a bucket of live crabs onto the body parts for this shot, but poor editing allowed one of the animals to be seen falling onto the pile.
Continuity mistake: At the end Brody throws the diving tank into the shark's mouth with the bottom first. When he shoots the tank it has turned round with the fat end facing out.
Continuity mistake: When Jaws jumps onto the back of the Orca, the Orca tilts to the right. After Quint gets killed Brody goes inside, and the Orca is tilting to the left without sinking anymore.
Revealing mistake: When the shark's jaws come down on Quint's stomach, look carefully and you can see Robert Shaw using his hand to push the shark's nose onto his stomach.
Continuity mistake: When Hooper first gets introduced in the movie on the pier, greeted by a fisherman, you notice in the background a man going down a ladder. Only for the camera to cut back to Hooper with the same man going down the same ladder again.
Continuity mistake: When Sheriff Brody is tossing chum to attract the shark, the cigarette between his lips is not lit but when he backs into the bridge of the boat, there is smoke trailing from the cigarette.
Continuity mistake: When all 3 men are putting the shark cage together for Hooper, and they move the cage over to the side of the boat, Brody is shirtless. Then the next shot where the cage is going into the water, Brody's black T-shirt is back on.
Character mistake: When Hopper is in the cage you can tell it isn't him by the size of the scuba tank on his back and size of that kill stick he was going to use. The tank and kill stick are almost as tall as the person in the cage. When on deck and loading into cage in scene before that the items aren't that tall.
Other mistake: Two errors when Hooper is at the helm...the first is Quint yelling at Hooper "starboard, ain't you watching?"the shark is actually running from the port side of Orca. The second is when Quintbtells Hooper to head SSE...Orca turns to starboard while moving ahead...a SSE course would be a turn to port.
Character mistake: In the scene on the boat, when Quinn, Hooper and Brody are gathered below, Quinn gives the date about the USS Indianapolis sinking as June 29, 1945. It is actually July 29, 1945. The first atomic bomb wasn't actually detonated until July16, 1945 in Alamogordo, New Mexico making it impossible for the Indianapolis to be delivering the bomb in June.
Continuity mistake: When Jaws leaves the pond after the attack its fins go below the water as it approaches the bridge, the scene immediately changes to the bridge, the woman is shouting "shark" and we see the fins go below the water again.
Other mistake: When Cooper is first examining the remains of Chrissy, the medical examiner takes her remains out of a cupboard of sorts, and carries them to a table. He doesn't struggle, and lifts the tray rather easily yet when Hooper is describing the remains of the body, he says "The torso has been severed mid thorax, the right arm has been severed above the elbow, the left arm, head shoulders sternum and portions of the rib cage are intact" The mistake is that Hooper describes way more of the remains than can have fit in the small tray and or be lifted so easily by the medical examiner.
Continuity mistake: When the man gets attacked the long shot shows two of the three boys on top of the upturned boat, then we see the leg sink to the bottom with a trainer on, even though the man was bare footed. Then the camera passes the boy in the water and the other two boys are only just climbing up onto the boat.
Continuity mistake: When the Kitner boy was attacked, the underwater shots show the swimmers treading water in fairly deep water, but the above shots show the kids standing in shallow water.
Visible crew/equipment: As Hooper says the shark is "back for his noon feeding", you can see the camera and lighting reflected on Brody's glasses.
Chosen answer: As mentioned in the movie, the posion was in the needle and the shark's hide was too tough for the needle to penetrate. Hooper had to go in the water so that he could get the needle into the shark's mouth, where the flesh was less tough.
Kevin Howard