There are three beach scenes in Jaws, each one providing a backdrop to a shark attack: the first, Chrissie Watkins; the second, Alex Kintner; the third, the unnamed estuary victim. The beach - like the darkened auditorium in which the moviegoer sits - is an arena for observation. The onlookers are forced into the role of audience, a role which precludes them from taking any action to prevent the outcome of events. In the first scene, Cassidy lies in a drunken stupour, oblivious to the horror taking place beyond the water's edge. In the second, the chief of police watches for but does not see the shark, and the only witness of the attack is not even sure what he sees. In the third, the entire community of Amity looks on as the hapless boatman is devoured, but even the grandstanding spectacle of his bloody death is not enough to hold the attention of a trio of bored girls sunbathing on the shore.
More than a geographical location, the shore (which, incidentally, is both the last word of the novel and the final image of the film) marks the division between the security of the land and the threat that lies beneath the surface of the water. Amity being a summer town, the beach is also the focus of economic transaction. The Fourth of July scene opens with examples of how the enterprising islanders are quick to turn a crisis into a sales opportunity, installing Shark Attack video games on the sea front and selling souvenir shark jaws.
The pacing and filming of each beach scene are significantly different. The first - with its relentless tracking shots - moves inevitably towards death whilst the third, burdened with multiple storylines, almost collapses under its own narrative complexity. It is in the second beach scene, however, that Spielberg manages to achieve a perfect balance and creates four minutes of tension that is unequalled in the rest of the movie.
The scene as filmed contains the essential action beats that were there in Benchley's novel: the crowded beach, the bored boy, the irritable mother - even the witness to the attack ('Did you see that?') - all are faithfully transferred from page to screen. The significant difference, however, is the presence of Brody, and it is his nervous, watchful gaze that informs the way we perceive the action. There are two parallel streams of visual information running through the sequence: the things that Brody sees (and the way he [mis]interprets them) and the things the viewer sees. This dichotomy - similar to the one Hitchcock creates between viewer and James Stewart's character in Rear Window - serves to ratchet up the tension. A dark shape in the water that might be a fin turns out to be an old man's bathing hat, and a young girl's sudden scream is the result not of a shark attack but horseplay. Brody sees evidence of the threat where there is none and yet fails to notice the key signifier - the dog's stick bobbing unclaimed in the waves - that telegraphs the presence of the shark to the viewer even before the underwater POV camera and throbbing music score make it explicit.