Bloodlust!

A group of unsupervised teen-agers vacationing in the tropics take a boat out to a seemingly uncharted deserted island. They soon find, however, that the island is inhabited by a wealthy recluse and his staff. While their host is initially hospitable, he quickly reveals his true purpose: to slowly hunt down and kill each of his visitors, as blood thirsty madman has done with everyone unlucky enough to set foot on his private island.