Two playboys in the coast of Mexico — Steven, an American millionaire and Miguel, a local swimming instructor — are competing to win the heart of beautiful Patricia. After they fight, Patricia gets eaten by the Tintorera. To cheer themselves up, they become friends and go to a brothel, having fun with two girls. They bring Gabriella, a British girl, with them, and go fishing for sharks and mantas, where Miguel gets eaten by the Tintorera. Gabriella, being shocked, returns to England. Steven, saddened by losing his friend, decides to cheer himself up by going to a brothel again. He throws a party with friends, and invites them to come to his yacht by swimming. Alas, they get eaten by the Tintorera. Steven, being fed up of this predator who goes eating all his friends, decides to eliminate it. He sets up a dragnet and destroys the shark with an explosive capsule.From the Wikipedia page for Tintorera, a 1977 Jaws rip-off.
EDIT: Damn it, you'd think I would have spelled the name of the movie right the first time: Tintorera, not Tintotera.