Lionel A. Walford, 73, a retired marine biologist, author, professor, and former Alexandria resident, died of cancer Monday in a convalescent home in Atlantic Islands, N.J. He lived in Rumson, N.J.

Dr. Walford joined the U.S. Fish and Wildlife Service in 1936 as an aquatic biologist. He came to Washington in 1945 as assistant chief of the service's information division, and was named chief of the branch of fishery biology three years later.

He directed the Sandy Hook (N.J.) Marine Laboratory from 1960 until retiring from the fish and wildlife service in 1971. In 1960, Dr. Walford received the Interior Department's Distinguished Service Award.

He taught at Santa Barbara (Calif.) State College and Harvard University. He had been an adjunct professor at Columbia University since 1964. Dr. Walford's books included "living Resources of the Sea" and "Game Fishes of the Pacific Coast from Alaska to the Equator," first published in the mid-1930s and recently reissued by the Smithsonian institution.

He was editor of a professional journal, Copeia, from 1937 to 1947, and was a member of the Explorers Club and the American Society of Icthyologists and Herpetologists.

Dr. Walford was born in San Francisco. He earned a bachelor's degree at Stanford University, and master's and doctoral degrees in biology at Harvard University.

He is survived by three daughters, Sarah Hollister, of Princeton, N.J, and Elizabeth Rassweiler and Christiana Walford, both of New York City, and three grandchildren.