- Bill very long and flattened, flat-oval in cross section
- Eye large
- A large, deep notch on both upper and lower caudal-fin origins
- A single, large median keel on each side of caudal peduncle
- Caudal fin large, forked and lunate
- 2 separate dorsal and anal fins (except in juveniles < ~80–90 cm LJFL)
- Scaleless (except in juveniles, that have scales until ~1 m in length)
Upper surfaces blackish brown, lighter brown below. Fins brown to dark brown.
To 450 cm TL and up to 536 kg in weight1. Females are generally larger than males.
Important conditions and life stages:
- First dorsal fin tall for much of its length
- Scales present
- No pelvic fins
Circumglobal in tropical, subtropical and sometimes cold waters.
Epi- and mesopelagic, oceanic, from the surface to at least 2,878 meters depth, found associated with drop-offs, offshore seamounts and submarine canyons. Swordfish tolerate a wide temperature range between 3–27°C, but prefer waters ranging between 18–22°C.
This species is an opportunistic feeder, foraging predominantly on pelagic squid but also pelagic fishes. It uses the sword-like bill to stun or kill their prey. Swordfish undertake diurnal vertical migrations, generally moving to greater depths with lower temperatures during the day to forage, returning to warmer surface waters at night.2,3 Swordfish also undertake large horizontal migrations, moving between tropical and temperate waters to reach believed feeding and spawning grounds4,3. Swordfish are a fast growing species, with males maturing at a smaller size and younger age than females. In eastern Australia, length were 50% of individuals become mature is estimated at 221 and 101 cm LJFL corresponding to 9.9 and 0.9 years for females and males respectively.5 In the southwest Pacific age where 50% of female swordfish become mature is 4.34 years using ray-based estimations, and 4.42 years using otolith-based estimations.6 Off the coast of southeast Florida, it is estimated that male swordfish begin to mature at ~100 cm LJFL equating to 1 year, with all males recorded mature by 150 cm LJFL, equating to 5 years. The smallest mature female was estimated at ~170 equating to 4 years, with all females becoming mature by 220 cm LJFL, equating to 9 years.7 In Eastern Australian waters, an extended spawning season occurs from September to May, peaking in December to February.8 Females display batch spawning and it is believed spawning occurs when water is <18°C. Maximum age estimates include 15 years9 18 years8 and 21 years in the southwest Pacific.6
Caught by drift gill nets, longline, harpooning and by set nets.