Biology

Oceanic but sometimes found in coastal waters (Ref. 9354). Generally above the thermocline (Ref. 9354), preferring temperatures of 18°C to 22°C (Ref. 9987). Larvae are frequently encountered at temperatures above 24 °C (Ref. 9702). Migrate toward temperate or cold waters in the summer and back to warm waters in the fall. Adults are opportunistic feeders, known to forage for their food from the surface to the bottom over a wide depth range (Ref. 9702). Feed mainly on fishes (Atlantic mackerel, barracudinas, silver hake, redfish, herring and lanternfishes (Ref. 5951)) but also on crustaceans and squids (Ref. 9354). They use their sword to kill their prey (Ref. 9354). Large individuals may accumulate large percentages of mercury in its flesh (Ref. 9354). Are batch spawners (Ref. 51846). Spawning takes place in Atlantic during spring in southern Sargasso Sea. Females grow fastest. Determination of age is difficult since the otoliths are very small and scales are missing in adults. Year rings have been successfully counted on cross sections of the fin rays (Ref. 35388). Pelagic eggs measure 1.6-1.8mm and the newly hatched larvae is 4 mm long. Sword is well developed at a length of 10mm and young live pelagically in the upper water layers where they quickly develop into very voracious predators (Ref. 35388). Mt DNA restriction analysis reveal that genetic differentiation occurs between populations inhabiting the Mediterranean Sea and the tropical Atlantic ocean, indicating little genetic exchange occurring between the two (Ref. 12784). Good food fish, marketed fresh or frozen, and can be made into sashimi, teriyaki or fillets (Ref. 9354).