Peter Benchley, whose novel “Jaws” terrorized millions of swimmers even as the author himself became an advocate for the conservation of sharks, has died Saturday at 65 at his home in Princeton, N.H. He had idiopathic pulmonary fibrosis, a progressive and a fatal scarring of the lungs.

Thanks to Benchley’s 1974 novel, and Steven Spielberg’s blockbuster movie of the same name, the simple act of ocean swimming became synonymous with fatal horror, of still water followed by ominous, pumping music, then teeth and blood and panic.

“Spielberg certainly made the most superb movie; Peter was very pleased,” Wendy Benchley told the Associated Press.

Benchley, the grandson of humorist Robert Benchley and son of author Nathaniel Benchley, was born in New York City in 1940. He attended the elite Philips Exeter Academy in New Hampshire, then graduated from Harvard University in 1961. He worked at The Washington Post and Newsweek and spent two years as a speechwriter for President Johnson, writing some “difficult” speeches about the Vietnam War, Mrs. Benchley said.

The author’s interest in sharks was lifelong, beginning with childhood visits to Nantucket Island in Massachusetts and heightening in the mid-1960s when he read about a fisherman catching a 4,550-pound great white shark off Long Island, the setting for his novel.

“I thought to myself, ‘What would happen if one of those came around and wouldn’t go away?”‘ he recalled. Benchley didn’t start the novel until 1971 because he was too busy working with his day jobs.

“There was no particular influence. My idea was to tell my first novel as a sort of long story … just to see if I could do it. I had been a freelance writer since I was 16, and I sold things to various magazines and newspapers whenever I could.”

While Peter Benchley co-wrote the screenplay for “Jaws,” and authored several other novels, including “The Deep” and “The Island,” Mrs. Benchley said he was especially proud of his conservation work.

The author did not abide by the mayhem his book evoked. In fact, he was quite at ease around sharks, his widow said. She recalled a trip to Guadeloupe, Mexico last year for their 40th wedding anniversary, when the two went into the water in a special cage.

Besides his wife, Peter Benchley is survived by three children and five grandchildren.