Black Marlins, Istiompax indica
Taxonomy Animalia Chordata Actinopterygii Perciformes Istiophoridae Istiompax indica
Description & Behavior
Black marlins, Istiompax indica (Cuvier, 1832), aka black marlin fishes, black-marlins, giant black marlins, marlins, Pacific black marlins, short nosed sword fishes, silver marlins, silver marlin fishes, and swordfishes, are a strong, fast pelagic species highly prized by sport fishermen. They have a dark blue dorsal (upper) side, a silvery-white belly and faint blue vertical stripes running down their sides. Their first dorsal fin is blackish to dark blue, while their other fins are dark brown, occasionally with blue tinges. They may have anywhere between 39 and 50 dorsal soft rays. Males may reach a length of 4.65 m and weight of 750 kgs, but females are generally much larger. The black marlin is the only marlin with non-retractable fins. Like all billfishes, this species has a distinctive elongated sword-like upper jaw. The black marlin's dorsal fin is proportionately the lowest of any billfish, standing less than 50 percent of the fish's body height. Scientists do not yet know how long members of this species live.
World Range & Habitat
A highly migratory species, black marlins, Istiompax indica, are usually found in shallow waters above the thermocline at 15 to 30° C, near shore close to continents, islands and coral reefs. Their depth ranges from 0 to 915 m, though they rarely swim below 30 m. In the Indo-Pacific, they inhabit both tropical and subtropical waters, occasionally entering temperate waters, but generally staying between 40° N and 45° S. Stray individuals may migrate into the Atlantic Ocean by way of the Cape of Good Hope, but no breeding populations appear to be permanent residents in the Atlantic.
Feeding Behavior (Ecology)
Black marlins feed on dolphinfish, squid, cuttlefish, octopuses, mackerels, trevallies, swordfish, and large decapod crustaceans, but prefers small tunas when abundant. Stomach analysis indicates that these fish use their long, sharp bills to slash their prey.
Conservation Status & Comments
Black marlins have not yet been evaluated as to whether they are a threatened or endangered species. Their flesh is marketed refrigerated or frozen in the United States and prepared as sashimi in Japan. However, they are banned in parts of Australia for their high selenium and mercury content.
References & Further Research
Research Istiompax indica » Barcode of Life ~ BioOne ~ Biodiversity Heritage Library ~ CITES ~ Cornell Macaulay Library [audio / video] ~ Encyclopedia of Life (EOL) ~ ESA Online Journals ~ FishBase ~ Florida Museum of Natural History Ichthyology Department ~ GBIF ~ Google Scholar ~ ITIS ~ IUCN RedList (Threatened Status) ~ Marine Species Identification Portal ~ NCBI (PubMed, GenBank, etc.) ~ Ocean Biogeographic Information System ~ PLOS ~ SIRIS ~ Tree of Life Web Project ~ UNEP-WCMC Species Database ~ WoRMS
Feedback & Citation
Start or join a discussion about this species below or send us an email to report any errors or submit suggestions for this page. We greatly appreciate all feedback!
Help Protect and Restore Ocean Life
Help us protect and restore marine life by supporting our various online community-centered marine conservation projects that are effectively sharing the wonders of the ocean with millions each year around the world, raising a balanced awareness of the increasingly troubling and often very complex marine conservation issues that affect marine life and ourselves directly, providing support to marine conservation groups on the frontlines that are making real differences today, and the scientists, teachers and students involved in the marine life sciences. Join us today or show your support with a monthly donation.
With your support, most marine life and their ocean habitats can be protected, if not restored to their former natural levels of biodiversity. We sincerely thank our thousands of members, donors and sponsors, who have decided to get involved and support the MarineBio Conservation Society.