All deep blue offshore waters of the Atlantic, the Bahamas and the Caribbean. Coloration varies a great deal.
Most common phase is dark blue, almost black on the dorsal surface, shading to whitish.
Usually, several vertical stripes are noticeable. Early in the 20th century, these variations led anglers to believe several species were involved. Science eventually determined that the Black and Striped Marlins are strictly Pacific species and that a Silver Marlin is non-existent. The Blue, however, is found in both hemispheres. The feature that distinguishes the Blue from others is the pointed dorsal fin that curves sharply downward.