The Blue Marlin is an extremely fast swimmer and is found throughout tropical and subtropical waters worldwide. It feeds on tuna and other fish, using it's bill to slash it's prey before swallowing it.
The Blue Marlin has an elongate body with a long stout bill that is rounded in cross section. It has two dorsal fins. The height of the first dorsal fin is less than the depth of the body. There are two anal fins, a lunate caudal fin and two strong keels on the side of the caudal peduncle.
The Blue Marlin is blue-black above and silvery below.
The blade-shaped pectoral fins can be depressed against the side of the body. In contrast, the curved pectoral fins of the Black Marlin cannot be depressed. Those of the Striped Marlin, Tetrapturus audax, are more leaf-shaped.
The Blue Marlin is found throughout tropical and subtropical waters worldwide.
In Australia Blue Marlin are recorded from most tropical and subtropical 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
Dietary items include tunas and other fishes. Less important food items include squids and large crustaceans. Analysis of stomach contents indicate that the Blue 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 Blue Marlin is a very fast swimmer.
- Graves, J.E. & J.R. McDowell. 2003. Stock structure of the world's istiophorid billfishes: a genetic perspective. Marine and Freshwater Research. 54:287-298.
- 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.