Conceived 32 years ago as producer Roger Corman’s tongue-in-cheek spin on the Jaws formula, Piranha returns with a new 3-D gimmick courtesy of director Alexandre Aja, who resurrected Wes Craven’s The Hills Have Eyes in 2006 with passably nasty results.

Aja's latest requires little explanation. It’s spring break under siege, as busty coeds lose their tops and then their limbs in graphic enough detail that Piranha, deemed too raunchy for Comic-Con, earns its R rating the old-fashioned way. It helps that besides the engaging Elisabeth Shue, Adam Scott (TV’s Party Down) and Richard Dreyfuss, who starred in Jaws, several members of the supporting cast are porn stars.

It’s not just to flash their privates – it’s to see them devoured by hungry, computer-animated fish. The movie isn’t intended as a measure of how far we’ve come in the annals of cinema, but then, no film inspired by Corman should be.

The violence is gory, gratuitous and convincingly staged, a credit to effects duo Howard Berger and Greg Nicotero (Predators), whose carnage looks impressively (or nauseatingly) real, even if the boobs are not. Also worthy of note are the veteran actors, including Shue, Ving Rhames and Christopher Lloyd, who gamely get into the lunatic spirit of things as Aja cheerfully ratchets up the body count.

Aja seems to understand better how to be scary than to move his narrative along at a fluid pace – Piranha sags in spots – but just as he captured the bruising feel of Hills, Craven’s 1978 minor cult classic, he efficiently replicates the campy, over-the-top spirit of Corman’s original fish story. If that’s what you’re looking for in a popcorn movie, you’ve come to the right place.