page_title: Swordfish
section_title: Behavior and ecology
hierarchical_section_title: Swordfish / Behavior and ecology
caption_attribution_description: English: Broadbill Swordfish - Xiphias gladius עברית: דג-חרב כלל-ימי
context_page_description: Swordfish, also known as broadbills in some countries, are large, highly migratory, predatory fish characterized by a long, flat, pointed bill. They are a popular sport fish of the billfish category, though elusive. Swordfish are elongated, round-bodied, and lose all teeth and scales by adulthood. These fish are found widely in tropical and temperate parts of the Atlantic, Pacific, and Indian Oceans, and can typically be found from near the surface to a depth of 550 m, and exceptionally up to depths of 2,234 m. They commonly reach 3 m in length, and the maximum reported is 4.55 m in length and 650 kg in weight.
  They are the sole member of their family, Xiphiidae.
context_section_description: Contrary to popular belief, the "sword" is not used to spear, but instead may be used to slash at its prey to injure the prey animal, to make for an easier catch.  Mainly, the swordfish relies on its great speed and agility in the water to catch its prey. It is no doubt among the fastest fish, but the basis for the frequently quoted speed of 97 km/h (60 mph) is unreliable. Research on related marlin (Istiophorus platypterus) suggest a maximum value of 36 km/hr (22 mph) is more likely.
  Swordfish prefer water temperatures between 18 and 22 °C (64 and 72 °F), but have the widest tolerance among billfish, and can be found from 5 to 27 °C (41 to 81 °F). This highly migratory species typically moves towards colder regions to feed during the summer. Swordfish feed daily, most often at night, when they rise to surface and near-surface waters in search of smaller fish. During the day, they commonly occur to depths of 550 m (1,800 ft) and have exceptionally been recorded as deep as 2,878 m (9,442 ft). Adults feed on a wide range of pelagic fish, such as mackerel, barracudinas, silver hake, rockfish, herring, and lanternfishes, but they also take demersal fish, squid, and crustaceans. In the northwestern Atlantic, a survey based on the stomach content of 168 individuals found 82% had eaten squid and 53% had eaten fish, including gadids, scombrids, butterfish, bluefish, and sand lance. Large prey are typically slashed with the sword, while small are swallowed whole.
  Swordfish are not schooling fish. They swim alone or in very loose aggregations, separated by as much as 10 m (33 ft) from a neighboring swordfish. They are frequently found basking at the surface, airing their first dorsal fin. Boaters report this to be a beautiful sight, as is the powerful jumping for which the species is known. This jumping, also called breaching, may be an effort to dislodge pests, such as remoras or lampreys.
  Almost 50 species of parasites have been documented in swordfish. In addition to remoras, lampreys, and cookiecutter sharks, this includes a wide range of invertebrates, such as tapeworms, roundworms, and copepods. A comparison of the parasites of swordfish in the Atlantic and in the Mediterranean indicated that some parasites, particularly Anisakis spp. larvae identified by genetic markers, could be used as biological tags and support the existence of a Mediterranean swordfish stock.
  Fully adult swordfish have few natural predators. Among marine mammals, killer whales sometimes prey on adult swordfish. The shortfin mako, an exceptionally fast species of shark, sometimes take on swordfish; dead or dying shortfin makos have been found with broken-off swords in their heads, revealing the danger of this type of prey. Juvenile swordfish are far more vulnerable to predation,  and are eaten by a wide range of predatory fish.
caption: Stuffed broadbill swordfish
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