Atlantic Cutlassfish

Atlantic Cutlassfish, Trichiurus lepturus

Atlantic Cutlassfish, Trichiurus lepturus. Commercial fish purchased at the Zion Market, San Diego, California, July 2015. Length: 1.15 m (3 feet 9 inches).

Atlantic Cutlassfish, Trichiurus lepturus. Fish caught from coastal waters off Charleston, South Carolina, December 2020. Length: 1.18 m (3 feet 10 inches). Catch, photograph, and identification courtesy of Josh Leisen (joshadventures.com), Gaylord, Michigan.

The Atlantic Cutlassfish, Trichiurus lepturus, is a member of the Cutlassfish or Trichiuridae Family, that is also known as the Largehead Hairtail and the Ribbonfish and in Mexico as sable del Atlántico. Globally, there are three species in the genus Trichiurus, of which two are found in Mexican waters, one in the Atlantic and one in the Pacific Ocean.

The Atlantic Cutlassfish has an extremely elongated and strongly compressed ribbon-like body that tapers to a point. They have a uniform silvery appearance being darker blue on their upper back and transitioning to silvery reflections ventrally with yellowish transparent fins. Their head has a long snout with large yellow eyes. They have a projecting lower jaw with a large mouth equipped with two or three pairs of large fangs and a series of sharp and compressed lateral teeth on both jaws. Their anus is closer to the tip of the snout than to the tip of the tail. Their anal fin has 100 to 105 rays which are exceedingly small and usually embedded in the skin; their dorsal fin has 3 spines and 130 to 135 rays and is high with a long base; their pectoral fins are mid-sized; and, they do not have caudal or pelvic fins. They do not have scales. Their lateral line begins at the upper margin of the gill cover, runs oblique to reach behind the tip of the pectoral fins, then continues straight across the ventral contour.

The Atlantic Cutlassfish is a benthopelagic and amphidromous species found in both marine and brackish environments over muddy bottoms of shallow coastal waters and in estuaries. They are found from the surface to depths of at least 610 m (2,000 feet) and prefer water temperatures above 21oC (70oF). They reach a maximum of 2.3 m (7 feet 8 inches) in length and 5.0 kg (11 lbs 0 oz) in weight. The current world angling record was caught in Brazilian waters in 1997 and weighed 3.7 kg (8 lbs 1 oz). As of January 1, 2023, the International Game Fish Association world record stood at 3.68 kg (8 lbs 1 oz) with the fish caught in coastal waters off Rio de Janeiro, Brazil in September 1997. They are vertical migrators (diel vertical migration) that move toward the surface for feeding and return to the bottom during the day for protection. The adults being ambush predators that attack from below and feed near the surface on crustaceans, fish, shrimp, and squid during the daytime, retreating to the bottom at night. Juveniles form schools and feed at night on planktonic organisms near the surface then retreat to the bottom during the day. Males maintain exclusive home ranges while females move around more. They are known to migrate seasonally to wintering and spawning grounds. They reproduce sexually, with each female releasing up to 130,000 eggs per year which are fertilized externally by the males. The eggs are scattered on the substrate and the subsequent pelagic larvae hatch in three to six days. They have lifespans of up to fifteen years.

The Atlantic Cutlassfish is a resident of all Mexican waters of the Atlantic Ocean including the Gulf of Mexico and the east coast of the Yucatán Peninsula in the Caribbean.

The Atlantic Cutlassfish is very similar to the Pacific Cutlassfish, Trichiurus nitens (smaller eyes; longer upper jaw; longer snout) and can also be confused with the Black Snake Mackerel, Nealotus tripes, the Snake Mackerel, Gempylus serpens, and the Striped Escolar, Diplospinus multistriatus, all of which have well-defined forked tails.

From a conservation perspective the Atlantic Cutlassfish is currently considered to be of Least Concern with stable, widely distributed populations. They are fished commercially, with the majority of commercial catches made in Asian waters of the Western Pacific using various types of nets, including trawls. Catch levels are approximately 1.5 tons per year placing it in sixth position in worldwide landing volume. Due to increased fishing pressure the body size of the average catch has been significantly reduced. They are marketed fresh, frozen, salted, and dried, with fresh fish used for sashimi and sold commercially in abundance as the Beltfish in the Asian markets of San Diego, California. They are also considered “excellent” when fried or grilled by some cultures but are not popular in the United States. In the Gulf of Mexico they are used as live bait, targeting large mackerel and wahoo, and as a quality cut bait for bottom fishing.