Island Jack, Carangoides orthogrammus
Island Jack, Carangoides orthogrammus. Fish caught off the beach, Cabo Real, Km 21, Baja California Sur, May 2020. Length: 49 cm (19 inches). One of the toughest beach foes on plant earth!
Island Jack, Carangoides orthogrammus. Fish caught from coastal waters off Point Palmilla, Baja California Sur, October 2017. Length: 51 cm (20 inches).
The Island Jack, Carangoides orthogrammus, is a member of the Jack or Carangidae Family, that is also known as the Island Trevally and the Yellow-spotted Trevally and in Mexico as jurel isleño. It was recently reclassified into the Ferdauia Genus but this change has not been widely accepted and thus I will stay with it as a Carangoides. There are twenty-two global members of the genus Carangoides, of which four are found in Mexican waters, two in the Atlantic and two in the Pacific Ocean.
The Island Jack has a deep elongated oval compressed body with a depth that is 35% to 40% of standard length. They are overall silvery in color with pale green markings dorsally and white ventrally and have two to seven large elliptical yellow spots with brown borders along their body close to the mid-line. Some fish have 9 or 10 dark vertical crossbars that run from the head to the caudal fin. Their soft anal, soft dorsal, and caudal fins are brilliant blue and their other fins are pale green. Their color changes drastically upon death as they darken to a dusky green to gray-green dorsally and silvery-green ventrally and their yellow spots become brown. Their head profile is high and gently sloping. They have a blunt snout, eyes set at snout level, and thick lips. Their anal fin has two standalone spines followed by 1 spine and 24 to 36 rays; the caudal fin has a slender base and is deeply forked; their first dorsal fin is low and has 8 spines; their second dorsal fin has 1 spine and 29 to 32 rays; and, their pectoral fins are long. Their anal and dorsal fin lobes are short. They have 30 to 33 gill rakers. They have 19 to 31 small scutes. The curved section of their lateral line is only slightly arched. Their body is covered with small scales.
The Island Jack is a circumtropical pelagic species that is found in and around rocky reefs at depths up to 190 m (625 feet). They reach a maximum length of 75 cm (2 feet 6 inches). The Island Jack 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 Island Jack has a wide global distribution being found in the Atlantic Ocean from East Africa to the Americas and in the Indian and Pacific Oceans. The Island Jack is a resident of Mexican waters of the Pacific but has a limited distribution being found only around the oceanic islands and the extreme southern portion of the Baja, from just into the Sea of Cortez (documented by a fish that I caught) to as far north as Todos Santos, Baja California Sur.
The Island Jack is most likely confused with the Bluefin Trevally, Caranx melampygus (blue anal, caudal, and dorsal fins; small blue and black spots on sides).
From a conservation perspective the Island Jack is currently considered to be of Least Concern. However, in Mexican waters they are rare and therefore of limited interest to most. In eastern, northern, and western coastal Australia they are targeted by surf fishermen. The fish photo above, of a Los Cabos fish, can also be found on page 331 of a book entitled “Fil-O-Fish”, a waterproof handbook of Australian fish where this fish is known locally as the Thicklip Trevally. When caught in Mexican waters they are retained by locals who consider them to be a good food fish.