Swordfish (Xiphias gladius)

The only member of the Xiphidae family, the swordfish is one of the most highly coveted big-game species in the ocean. Swordfish have been overexploited worldwide, and today fish under 100 pounds - which have likely never had the opportunity to spawn once - are primarily encountered, in some places only rarely, and too few are released alive.

Other Names

broadbill, broadbill swordfish; Arabic: kheil al bahar; French: espadon; Hawaiian: a’u ku; Italian: pesce sapda; Japanese: dakuda, medara, meka, mekaiiki; Norwegian: sverdfisk; Portuguese: agulha, espadarte; Spanish: aja para, aibacora, espada.


The swordfish has a stout, fairly rounded body and large eyes. The first dorsal fin is tall, nonretractable, and crescent-shaped. The second dorsal fin is widely separated from the first and very small. Both are soft rayed, having thin, bony rods that extend from the base of the fin and support the fin membrane.

The anal fins approximate the shape of the dorsal fins but are noticeably smaller. Ventral fins, on the underside of the fish, are absent. There is a strong longitudinal keel, or ridge, on either side of the caudal peduncle, which leads to a broad, crescent-shaped tail. Adult swordfish have neither teeth nor scales.

The back may be dark brown, bronze, dark metallic purple, grayish-blue, or black. The sides may be dark like the back or dusky. The belly and the lower sides of the head are dirty white or light brown.

The swordfish snout elongates into a true sword shape. Measuring at least one-third the length of the body, it is long, flat, pointed, and very sharp (especially on smaller fish) and significantly longer and wider than the bill of any other billfish. The lower jaw is much smaller, although just as pointed, ending in a very wide mouth.

The bodies of swordfish fry are quite different from those of adults. Their upper and lower jaws are equally prolonged. Their bodies are long, thin, and snakelike; are covered with rough, spiny scales and plates; and have just one long dorsal and one anal fin.

Although they are distinctive fish, they do bear some resemblance to the spearfish, which is distinguished from the swordfish by its rounded sword, small teeth, a long continuous dorsal fin, and ventral fins.


Swordfish are capable of growing to well over a thousand pounds, although fish of this size are unheard of in modern times. In the North Atlantic, a fish weighing more than 400 pounds is extremely unusual, and the average fish caught in the commercial fishery there weighs less than half of this, with reports varying from under 90 pounds to under 200.

The all-tackle world record, caught in 1953, weighed 1,182 pounds. The larger fish measure approximately 15 feet in length and have 10-foot-long bodies and 5-foot-long swords.

Female swordfish grow faster, live longer, and are proportionally heavier than their male counterparts. Very large swordfish are always females; males seldom exceed 200 pounds. The maximum longevity of swordfish is unknown, but they do live for at least 9 years. Most swordfish caught in the North Atlantic sportfishery are thought to be immature fish, only up to 2 years old.

Life history/Behavior

Swordfish swim alone or in loose aggregations, separated by as much as 40 feet from a neighboring swordfish. They are frequently found basking at the surface, airing their first dorsal fins. Boaters report this to be a beautiful sight, as is the powerful free jumping for which the species is known.

This free jumping, also called breaching, is thought by some researchers to be an effort to dislodge pests, such as remoras or lampreys. It could also be a way of surface feeding by stunning small fish. They reach sexual maturity at about 2 to 3 years of age.

Food and feeding habits

Swordfish feed daily, most often at night. They may rise to surface and near surface waters in search of smaller fish or prey upon abundant for age at depths to 1,200 feet. Squid is the most popular food item, but they also feed on menhaden, mackerel, bluefish, silver hake, butterfish, herring, and dolphin.


Swordfish occur in tropical, temperate, and occasionally cold waters of the Atlantic, the Pacific, and the Indian Oceans. They generally migrate between cooler waters in the summer to warmer waters in the winter for spawning. In the Atlantic Ocean, swordfish range from Canada to Argentina.


These are pelagic fish living within the water column, rather than on the bottom or in coastal areas. They typically inhabit waters from 600 to 2,000 feet deep and are believed to prefer waters where the surface temperature is above 58°F, although they can tolerate temperatures as low as 50°F.

There seems to be some correlation between larger size and the ability to tolerate cooler temperatures. Few fish under 200 pounds are found in waters with temperatures less than 64°F.

In the western Atlantic, swordfish are summer and fall visitors to New England waters, entering the warming Atlantic coastal waters from far offshore in the Gulf Stream around June and departing in late October.

Evidence suggests that such onshore-offshore seasonal migrations are more prevalent than are migrations between the northern feeding areas off Cape Hatteras and the southern spawning grounds off Florida and the Caribbean.