Blue Marlin

Blue marlin are cobalt-blue above and silver below with pale vertical bars that light up electric blue when the fish is excited. The dorsal fin is tall and pointed, the pectorals fold flat against the body, and the bill is long and round. Atlantic and Pacific populations are now treated as one species. They range through tropical and warm temperate oceans, following the 75–85 °F (24–29 °C) water that holds their prey, and females grow several times larger than males; every fish over about 300 lb is female.

Blues are open-ocean hunters that cruise the upper water column along current edges, temperature breaks, seamounts and weed lines, eating tuna, dolphinfish, squid and mackerel. They are usually raised by a trolled spread rather than found, and an aggressive blue will crash a lure or bait in a shower of spray before taking off on a run that can strip hundreds of yards in seconds. Kona, Hawaii, Bermuda, the Gulf of Mexico canyons, the Azores, Madeira and Brazil are the storied grounds, and most modern fisheries release nearly every fish.