"Blue Water, White Death" (1971) and Jaws
In the rather less corporate, more shambling movie releasing summer of 1971, a friend of mine invited me to go see a movie called "Blue Water, White Death."
It wasn't a fiction film. It was a documentary about great white sharks. filmed, as I recall, off Austrailia with Aussie divers and scientists.
My friend wanted to see it, he told me, because he had a deathly fear of sharks and he wanted to be scared.
I found it a little boring(a documentary, after all) but quite scary at times when the sharks appeared.
I can't say that I remember the movie much in content, but I do remember a scene where they lowered a guy in a shark cage and sure enough, the shark attacked the cage.
Flash forward four years to the summer of 1975 : Jaws is out and a BIG blockbuster, and I reminded my friend: "Hey, you were onto this four years ago with Blue Water, White Death."
I then read somewhere that Spielberg used the documentary fillmakers of Blue Water, White Death to help do second unit on Jaws. The scene with Hooper(Dreyfuss) getting attacked in the cage was at least partially filmed off Australia by the "Blue Water, White Death" guys.
I can't say that "Blue Water, White Death" is as interesting as Jaws(there are no fun fictional characters like Brody, Hooper, and Quint)...but it is a good companion piece.