SAWFISH: A Deep Sea Thriller
Dr. Rayman doesn't let on that it's his fish responsible for the killings, but someone knows what he did, and she's blackmailing him. He plays along for a while but then decides she needs to be eliminated. Breaking into a lab at his former workplace, he deliberately creates more monster sawfish and releases them into the local waters.
Rayman then attempts to get his job back by stepping forward as the expert on how to stop the scourge of gigantic predators now ravaging swimmers and water sports enthusiasts on South Florida beaches. But his blackmailer will not let up, leading to an ultimate confrontation between woman and beast, and finally, woman and man.