In the late 1940s Chaplin began his ichthyological work in
Nassau, Bahamas, as a research associate for Philadelphia's
Academy of Natural Sciences.
Fishes of the Bahamas and Adjacent Waters Over the next 15 years, working with his Academy colleague
Dr James Böhlke, he studied and collected over 500 species of Bahamian fishes, 65 of them never before described. Their work led to the co-authorship of
Fishes of the Bahamas and Adjacent Tropical Waters (1968, with a new edition published in 1992). The book remains the "primary reference for the identification of West Indian fishes". Chaplin and Bohlke pioneered the use of SCUBA gear and the organic ichthyocide
rotenone in collecting specimens. with a pioneering waterproof edition that could be taken underwater by divers. Waterproof fish guides have since become standard.
Exuma Cays and Sea Park In 1959, Chaplin and a group of
conservationists from Nassau including
Ilya Tolstoy, grandson of the writer Leo Tolstoy, founded the
Exuma Cays Land and Sea Park, one of the world's first underwater marine reserves. To oversee the park's operation, they established the
Bahamas National Trust. ==Awards==