Learning marine biology from a textbook is one thing. But take readers to the bottom of the sea in a submarine to discover living fossils or to coral reefs to observe a day in the life of an octopus, and the sea and its splendors come into focus, in brilliant colors and with immediacy.

In Sensuous Seas, Eugene Kaplan offers readers an irresistibly irreverent voyage to the world of sea creatures, with a look at their habitats, their beauty and, yes, even their sex lives. A marine biologist who has built fish farms in Africa and established a marine laboratory in Jamaica,...