Empire of the Sharks

In the future, most of Earth is covered by water. The only land left is controlled by a lone warlord and his army of ever-vigilant, hyper-intelligent sharks. The humans are forced to pay tribute to the warlord, and the unlucky ones are caged up and kept as food for the shark army. But when two friends risk their lives to rescue a trapped prisoner, those imprisoned decide to rise against their captor and his legion of bloodthirsty sharks.