Atlantic Agujón, Tylosurus acus acus

Atlantic Agujón, Tylosurus acus acus, Juvenile. Fish caught from coastal waters off Long Island, New York, September 2023. Length: 8.4 cm (3.3 inches). Catch, photograph and identification courtesy of Aidan Perkins, Long Island, New York.

Atlantic Agujón, Tylosurus acus acus. Fish caught from coastal waters off Ft. Lauderdale, Florida, September 2022. Length: 1.02 m (3 feet 4 inches). Catch, photograph and identification courtesy of Ben Cantrell, Sebastian, Florida.

The Atlantic Agujón, Tylosurus acus acus, is a member of the Needlefish or Belonidae Family, and are also known as the Agujón Needlefish and in Mexico as aguja, agujón del Atlántico and marao ojón. Globally, there are four subspecies of the Atlantic Agujón, Tylosurus acus acus found in Mexican waters of the Atlantic and the Keel-jaw Needlefish, Tylosurus acus melanotus that occurs in the Indo-Pacific and in Mexican waters is limited to the Clipperton, Revillagigedo, Cocos, and Tres Marias Islands. There are six species in the genus Tyosurus of which two are found in Mexican waters of the Atlantic Ocean.

The Atlantic Agujón has a very elongated slender, rounded body with extremely elongated jaws that form a long upcurved beak with numerous needle-like teeth. They have a dark blue upper body that transitions to silver ventrally with a blue stripe along the flank. This countershading affords them camouflage to avoid predation. Their anal fin has 19 to 22 rays; their caudal fin is deeply forked with a longer lower lobe and their caudal fin base has a small black keel; their dorsal fin has a long base with 22 to 26 rays which is expanded posteriorly in juveniles; their pectoral has 13 or 14 rays and is short, and the pelvic fins have six rays and are being shorter than the pectoral fins. Their anal and dorsal fins have low lobes at the front. Their body is covered with small scales. They do not have gill rakers.

The Atlantic Agujón are found in the first 10 m (33 feet) of the water column. They reach a maximum of 1.40 m (4 feet 7 inches) in length and 3.7 kg (8.1 lbs) in weight. They are found in both coastal and oceanic waters. Adults are voracious predators feeding on fish and crustaceans. Reproduction is oviparous with females laying large spherical eggs which attach themselves to floating vegetation. The Atlantic Agujón is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, growth, longevity, movement patterns, diet, habitat use, and reproduction.

The Atlantic Agujón 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 Agujón can be confused with the Atlantic Needlefish, Strongylura marina (straight caudal fin) and the Giant Mexican Needlefish, Tylosurus fodiator (short straight beak, high anal and dorsal fins, long pectoral and pelvic fins).

From a conservation perspective, the Atlantic Agujón are currently considered to be of Least Concern, with stable, widely distributed populations. They are of minor commercially importance, caught via hook and line and via nets that are retained by artisanal fishermen and sold regionally in local markets but not a favorite due to the green-colored flesh.