Green Jack, Caranx caballus
The Green Jack, Caranx caballus, whose common Spanish name is jurel bonito and whose local name is cocinero, is a fairly common member of the Jack or Carangidae Family, known collectively as jureles and pámpanos in Mexico. Globally, there are seventeen species in the genus Caranx, nine of which are found in Mexican waters, three in the Atlantic and five in the Pacific and one in both oceans.
The Green Jacks have moderately compressed relatively slender rectangular bodies with a depth that is 26 to 30% of standard length. They are overall light olive to dark blue-green with a silvery to golden coloration ventrally. They have seven pale narrow vertical bars spaced about one inch apart along their sides that fade quickly upon collection. Their head profile is convex and gently sloping with a blunt snout and fairly large eyes set just above the mid-line. Their mouth is small and opens at the front. Their gill cover has a black spot located halfway between the pectoral fin base and the end of the lateral line. All their fins are pale. They have a deeply forked caudal fin and two equally-sized dorsal fins. Their pectoral fins are exceedingly long, a key to identification. They have 28 to 30 gill rakers and 45 to 56 strong prominent scutes. Their lateral lines is pronounced with a short anterior arch.
The Green Jacks are a common pelagic schooling species found over all types of terrain at depths up to 330 feet. They reach a maximum length of 70 cm (28 inches). They are a poorly studied species and very little is known about their behavior patterns.
In Mexican waters the Green Jacks are found in all waters of the Pacific and can occasionally be seen on the surface traveling in large schools and bait balls.
The Green Jack is identical in appearance and morphology to the Blue Runner, Caranx crysos, found in the Atlantic Ocean, with the exception that the Green Jack has 28 to 30 gill rakers versus 35 to 42 for the Blue Runner and the Green Jack’s head profile is slightly narrower at the eyes (15-16% of standard length versus 17-18% for the Blue Runner). In the Pacific, the Green Jack is most likely confused with the Bigeye Trevally, Caranx sexfasciatus (large eye; smaller black spot high on gill cover) and the Cocinero, Caranx vinctus (dark bars on sides; yellow fins).
The Green Jacks are normally caught in shallow waters including off the beach and are considered an insignificant catch. Although they are readily available at certain times of the year, local fishermen do not view them as quality live bait. They are considered marginal table fare and normally a “catch and release” by all but subsistence fishermen.