Istiophoridae

Black marlin

Istiompax indica

Rigid sickle fins sweeping past coral reefs

• Black
• Gray
• Silver
• Tropical
• Globally widespread
• Marine fish
• Fusiform
• Large
• Tropical fish

Reigning as the most colossal heavyweight among all apex billfishes on Earth, the black marlin is an immense oceanic macropredator renowned for its rigid pectoral fins and titanic open-sea power. Its massive, robust torso presents a dark slate-blue to inky black dorsal surface that transitions sharply into silvery-white sides and belly, crowned by a relatively short, stout, non-retractable first dorsal fin. The definitive morphological hallmark that sets it apart from all other billfishes is its rigid, wing-like pectoral fins, which are fixed perpendicularly and cannot be folded flat against the body flanks. Distributed throughout tropical and subtropical expanses of the Indian and Pacific Oceans from the surface down to two hundred meters depth, it cruises continental shelf drop-offs, deep submarine canyons, and island passes. An apex pursuit predator, it hunts skipjack tunas, mackerel, dolphinfish, and large pelagic squids, using its heavy, rounded bill to impale and stun quarry. Females attain gigantic proportions, with recorded maximum lengths of four hundred and sixty-five centimetres and masses exceeding seven hundred kilograms.

Sources: Australian Museum — Black Marlin, Istiompax indica