"friendly they guide him to prey..."
See in text (Text of the Poem)
In the final quatrain, Melville echoes a common myth about pilot fish. While the precise source of the term “pilot fish” is not known, sailors have for millennia observed the behavior of the “friendly” pilot fish and assumed that they helpfully “pilot” sharks toward prey and ships toward safe harbor. Scientists have debunked these accounts but the name “pilot fish” has remained.