The writer, whose 1974 best-selling novel was adapted into Steven Spielberg's movie blockbusters, died from idiopathic pulmonary fibrosis, a progressive and a fatal scarring of the lungs, his widow WENDY confirmed.
Despite his novel turning sharks into objects of fear for millions of people around the world, the author was a long-time campaigner for the conservation of the sea creatures.
Wendy says, "Spielberg certainly made the most superb movie; Peter was very pleased.
"But Peter kept telling people the book was fiction, it was a novel, and that he no more took responsibility for the fear of sharks than Mario Puzo took responsibility for the Mafia."
Betchley is survived by three children and five grandchildren.