Who wants to go swimming?
Hard to believe that this was made back in 1975, no I didn't see this at the cinema (too young), which is probably why I tend to think of this as more of an 80's movie. Either way Spielberg manages to build the suspense without actually showing a shark eating a human until well into the film.
In essence we have a great white shark that has acquired a taste for human flesh, and it goes on a feeding spree. However the local major of the small town seems to be more worried about the financial impact of closing the beaches, and hence finds various reasons not too. Anyone see more dead people coming?
The theme of the "expert" warning about the situation and then being overrules/ignored seems to be reoccurring Hollywood theme. The expert is typically proven to be in the right and is eventually listened too. The ending typically comes to a showdown between the expert and the event/thing that they were warning everyone about.
As it is Hollywood, no prizes for guessing that our hero usually triumphs, so it is in this film.