Swordfish (Xiphias gladius) are large, highly migratory predators characterized by a long, flat bill in contrast to the smooth, round bill of the marlins. Swordfish are elongate, round-bodied, and lack teeth and scales as adults. They reach a maximum size of 14 feet and 1,190 pounds. The International Game Fish Association's all-tackle angling record is a 1,182-pound fish taken off Chile in 1953.
Swordfish are distributed throughout the world's marine ecosystem, in tropical, subtropical and temperate waters and tend to concentrate where major ocean currents meet, and along temperature fronts. They inhabit the mixed surface waters where temperatures are greater than 15C but also can move into water as cool as 5C for short periods aided by specially adapted brain and eye heat exchange organs.
Areas of greater apparent abundance occur north of Hawaii along the North Pacific transition zone, along the west coasts of the U.S and Mexico and in the western Pacific, east of Japan. Migration patterns have not been described although tag release and recapture data indicate an eastward movement from the central Pacific, north of Hawaii, toward the U.S. West Coast. Acoustic tracking indicates some diel movement from deeper depths during the daytime and moving into the mixed surface water at night. At times they appear to follow the deep scattering layer, and small prey, as they undertake these vertical movements.
Females grow larger than males, as males over 300 pounds are rare. Females mature at 4-5 years of age in northwest Pacific while males mature first at about 3 to 4 years. In the North Pacific, batch spawning occurs in water warmer than 24C from March to July and year round in the equatorial Pacific. Adult swordfish forage includes pelagic fish including small tuna, dorado, barracuda, flying fish, mackerel, as well as benthic species of hake and rockfish. Squid are important when available. Swordfish likely have few predators as adults although juveniles are vulnerable to predation by large pelagic fish.