Black Marlin, Istiompax indica Click to enlarge image
A Black Marlin taking a lure off Sydney, New South Wales, January 2014. Image: Peter Somogyi
© Peter Somogyi

Fast Facts

  • Classification
  • Size Range
    The species grows to over 4.48 m in length and over 700 kg.


The Black Marlin is a well known commercial and recreational fishing species. The species occurs in tropical and subtropical waters throughout the Pacific and Indian Oceans, and sometimes also found in temperate waters. It uses its bill to slash prey before swallowing it.


The Black Marlin has an elongate body with a stout bill, that in cross section is rounded. It has two dorsal fins, two anal fins, a lunate caudal fin and two strong keels on the side of the caudal peduncle. The pelvic fins can be depressed into a groove. The pectoral fins stick out from the side of the body and cannot be depressed. The Black Marlin is dark blue above, silvery below and usually lacks any markings.

According to Pepperell (2010), the Black Marlin is the only istiophorid in which the second dorsal fin is anterior to the second anal fin, this feature holds for all sizes.

For many years the Black Marlin was called Makaira indica. The species is currently classified in the genus Istiompax.

Black Marlin <i>Istiompax indica</i> skeleton

Black Marlin, Istiompax indica, skeleton (I.38913-001)

Image: Abram Powell
© Australian Museum


The Black Marlin occurs in tropical and subtropical waters throughout the Pacific and Indian Oceans.

Individuals are occasionally found in the Atlantic Ocean. These are presumed to have migrated around the Cape of Good Hope.

The species is sometimes also found in temperate waters.

Its distribution encompasses all Australian marine waters.

The map below shows the Australian distribution of the species based on public sightings and specimens in Australian Museums. Click on the map for detailed information. Source: Atlas of Living Australia.

Feeding and diet

Food items consist largely of other large fast swimming fishes such as tunas, mackerels, trevallies, and swordfish. Less important foods include other fishes, squids, and large crustaceans. Analysis of stomach contents indicate that the Black Marlin uses its bill to slash prey before it is swallowed.

Other behaviours and adaptations

Like all the other fishes in the family Istiophoridae, the Black Marlin is a very fast swimmer.

A Black Marlin off the Great Barrier Reef

Black Marlin, Istiompax indica

Image: Julian Pepperell
© Julian Pepperell

Economic impacts

The Black Marlin is a well known commercial and recreational fishing species. In areas of north-eastern Australia, Peru and Ecuador, sportfishing for Black Marlin by trolling is an important industry.


  1. Hoese, D.F., Bray, D.J., Paxton, J.R. & G.R. Allen. 2006. Fishes. In Beesley, P.L. & A. Wells. (eds) Zoological Catalogue of Australia. Volume 35. ABRS & CSIRO Publishing: Australia. parts 1-3, pages 1-2178.
  2. Nakamura, I. 1985. FAO species catalogue. Vol. 5. Billfishes of the world. An annotated and illustrated catalogue of marlins, sailfishes, spearfishes and swordfishes known to date. FAO Fish. Synop. No. 125 (5): i-iv, 1-65.
  3. Pepperell, J. 2010. Fishes of the Open Ocean. A natural history & illustrated guide. University of NSW Press. Pp. 266.