Swordfish (Xiphias gladius) can reach a maximum size of over 14 feet and 1400 pounds – but they start out tiny. As seen in the picture, a newly hatched baby is not even the size of a person’s finger. They grow fast, though; according to ichthyologist Juan C. Levesque in an interview with the “Florida Sportsman Magazine,” a young swordfish can grow 39 inches during its first year. While a swordfish grows throughout its life, the pace slows as it ages.
The species name, gladius, means “sword” and swordfish, being powerful fighters, can be described as the “gladiators of the sea.” They are predators throughout their lives. Larval swordfish prefer the larvae of other fish, although they will eat zooplankton. Juveniles and adults both feed on fish, squid and pelagic crustaceans.
Swordfish are the most widely distributed of the billfish, a group that also includes marlins and sailfish, and they have been found in tropical and temperate regions of the Pacific, Indian and Atlantic Oceans. In the North Atlantic, they have ranged as far north as Newfoundland and as far south as Argentina. Similarly, they can range from the ocean’s surface to depths of 3700 feet. They can tolerate water temperatures of 41° F to 81° F – the widest temperature range of any billfish.
Scientists have found that swordfish migrate vertically. They swim near the surface at night and go down deeper during the day. They also make long seasonal migrations and swim to cooler waters in the summer and warmer waters in the winter.
Like most fish, swordfish lay eggs, and a big female can produce up to 8.7 million eggs. Males reach maturity by the age of five years, while females do so by the age of nine. Female swordfish are typically larger than the males.
