Jack, Crevalle

The crevalle jack has a body depth of about three times its fork length. It has large eyes. The chest is scaleless except for a small patch of scales in front of the pelvic fins. This patch is apparent by the time the fish reaches a fork length of 0.98 inches (2.5 cm). The crevalle jack is the only jack in the western Atlantic Ocean with this patch of scales. There is an oval black spot on the pectoral fins; this appears at about 4.72 inches (12.0 cm). Between the seventh and the eighth spines of the adult there is an overgrowth of skin. The two most distinguishable features of this fish are the patch of scales between the pelvic fins and the oval, black spot on the pectoral fins. he crevalle jack is greenish-bluish or bluish-black above and silvery white to yellowish or golden below. This serves to blend in with the water from a predator searching from above, and to blend with the sunlight from a predator hunting from below. There is an oval, black spot on the pectoral fins. Juveniles have 5 dark bars on their bodies. These black bars are present until the fish reaches a size of 6.46 inches (16.4 cm). There is an area of dark pigment above the peduncle that appears at 1.18 in. (3.0 cm) and is very dark once the fish reaches a size greater that 3.94 inches (10.0 cm) in length.