Many people's fear of sharks can be traced back to Steven Spielberg's 1975 breakthrough movie, Jaws. The film was based on a book by Peter Benchley, and it now seems like the source material and Benchley himself was a lot less anti-shark than Spielberg was at the time. Over the following decades, Benchley turned into one of the greatest defenders of sharks and advocate for the oceans, possibly - on some level - out of guilt, seeing how his fiction work embedded so deeply into popular culture the image of the shark as an 'enemy' of the people that must be killed.
Benchley even went as far as to say: "The shark in an updated Jaws could not be the villain; it would have to be written as the victim; for, worldwide, sharks are much more the oppressed than the oppressors."
Here are a couple of interesting videos showing Benchley's evolution over time as an ocean activist:
If you want the whole story of his journey with sharks and the oceans, there's a great long-form piece at Narrative.ly.
You can find more on Peter Benchley's official website, including some photos from the shooting of Jaws, some of Benchley's own shark photos from expeditions, and a lot more info about his books, movies, and conservation efforts.