William W. Warner, a former administrator at the Smithsonian Institution and the author of “Beautiful Swimmers,” a study of crabs and watermen in the Chesapeake Bay, which won the Pulitzer Prize for nonfiction in 1977, died on April 18 at his home in Washington. He was 88.

The cause was complications of Alzheimer’s disease, said his daughter Alexandra Nash.

A weekend sailor and lifelong nature enthusiast, Mr. Warner spent endless hours on what he called the “benign and beautiful” waters of the Chesapeake Bay, which teemed with Atlantic blue crabs and supported 9,000 full-time watermen when he wrote “Beautiful Swimmers,” a blend of history, ecology and anthropology.

Despite its somewhat rarefied subject, the book captivated critics and readers