Leatherjack, Oligoplites saurus

Leatherjack, Oligoplites saurus. Fish caught from coastal waters off Key Largo, Florida, December 2013. Length: 25 cm (9.8 inches). Catch, photograph and identification courtesy of Ben Cantrell, Peoria, Illinois.

Leatherjack, Oligoplites saurus. Fish caught from coastal waters off Key Largo, Florida, December 2013. Length: 28 cm (11 inches). Catch, photograph, and identification courtesy of Josh Leisen (joshadventures.com), Gaylord, Michigan.

The Leatherjack, Oligoplites saurus, is a member of the Jack or Carangidae Family, and is known in Mexico as piña sietecueros. There are six global members of the genus Oligoplites, of which four are found in Mexican waters, one in the Atlantic and three in the Pacific Ocean. Some scientists believe there are two subspecies of the Leatherjack, the Atlantic Leatherjack, Oligoplites saurus inornatus in the Atlantic and the Pacific Leatherjack, Oligoplites saurus saurus in the Pacific, while others believe they are individual species – the Leatherjack, Oligoplites saurus in the Atlantic and the Yellowtail Leatherjack, Oligoplites inornatus, from the Pacific Ocean, which is my treatment.

The Leatherjack has an elongated very compressed body that has a depth that is 24% to 28% of standard length. They are uniformly silvery-green in color. They have clear anal and dorsal fins and a yellow caudal fin. Their head has a pointed snout. Their mouth has 2 rows of teeth and ends beyond the rear margin of the pupil. Their anal fin has 2 standalone spines followed by 1 spine and 19 to 22 rays; their caudal fin has a slender base and is deeply forked; their first dorsal fin has 5 spines; their second dorsal fin has 1 spine and 19 to 22 rays; and, their pectoral fins are short. They have 17 to 21 and 13 to 16 gill rakers. Their anal and dorsal fin bases are of equal length and both end with 11 to 15 semi-detached finlets. Their lateral line is slightly arched above the pectoral fins but is generally straight. Their body is covered with small needle-shaped scales and has no scutes.

The Leatherjack is a pelagic schooling species found inshore over sandy beaches, bays, and in estuaries at depths up to 50 m (165 feet) and known to enter fresh water. They reach a maximum length of 45 cm (18 inches). The Leatherjack 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 Leatherjack is found in all Mexican waters of the Atlantic including the Gulf of Mexico and the Caribbean.

The Leatherjack is virtually identical to the Yellowtail Leatherjack, Oligoplites inornatus, from the Pacific Ocean and can also be confused with the Longjaw Leatherjack, Oligoplites altus (wider body; mouth extending behind eyes) and the Shortjaw Leatherjack, Oligoplites refulgens (thinner body; mouth ends before pupils).

From a conservation perspective the Leatherjack is currently considered to be of Least Concern with stable, widely distributed populations. They are a focus of recreational anglers as they are considered excellent foe on light tackle and provide a strong fight with jumping. They are also caught with nets by commercial fishermen but are small in stature and of limited interest. As a food fish, they are considered somewhere between marginal and good. Their dorsal and anal spines are reported to be venomous, and should be avoided.