There have been more than 50 shark movies since Steven Spielberg made cinematic history with "Jaws" in 1975.

This year's shark movie, which will open in the US on June 16, takes place almost entirely under water.

Sisters Lisa and Kate -- played by Mandy Moore and Claire Holt -- are on vacation in the Gulf of California, and it becomes clear that they should avoid climbing aboard a flimsy boat belonging to Taylor (Matthew Modine).

They also probably should not get inside Taylor's rusty shark cage to plunge into the water and observe the predators up close.

Modine's character attracts the sharks by pouring blood into the water -- before the cage breaks away from the boat and drops to the ocean floor.

The two young women with little diving experience find themselves in the dark with less than an hour of air in their oxygen tanks -- surrounded, of course, by hungry sharks.

- 'Physically taxing' -

"What I found far more terrifying is the prospect and premise of drowning, of running out of air," Moore told reporters.