The Crevalle Jack is a common species of large marine fish classified within the jack family, Carangidae. It is distinguishable from similar species by its deep body, fin colouration and a host of more detailed anatomical features, including fin ray and lateral line scale counts. The Crevalle Jack inhabits both inshore and offshore waters to depths of around 350 m, predominantly over reefs, bays, lagoons and occasionally estuaries. Young fish dispersed north by currents in the eastern Atlantic are known to migrate back to more tropical waters before the onset of winter; however, if the fish fail to migrate, mass mortalities occur as the temperature falls below the species' tolerance limits.
The Crevalle Jack is a powerful, predatory fish, with extensive studies showing the species consumes a variety of small fish, with invertebrates such as prawns, shrimps, crabs, molluscs and cephalopods also of minor importance. Dietary shifts with both age, location and season have been demonstrated, which led some researchers to postulate the species is indiscriminant in its feeding habits. The Crevalle Jack reaches maturity at 55 cm in males and 66 cm in females, with spawning taking place year round, although peaks in activity have been documented in several sites. The larval and juvenile growth has been extensively studied, with the oldest known individual 17 years of age. The Crevalle Jack is an important species to commercial fisheries throughout its range, with annual catches ranging between 1000 and 30 000 tonnes over its entire range. The species is considered of good to poor quality table fare, and is sold fresh, frozen, or preserved, or as fishmeal or oil at market. The Crevalle Jack is closely related to both the Pacific Crevalle Jack and the Longfin Crevalle Jack, the latter of which has been extensively confused with the true Crevalle Jack until recently.
The Crevalle Jack is one of the largest members of Caranx, growing to a known maximum length of 125 cm and a weight of 32 kg, although it is generally uncommon at lengths greater than 65 cm. Unverified reports of fish over 150 cm may also be attributable to this species. The Crevalle Jack is morphologically similar to a number of other deep-bodied carangids, having an elongate, moderately compressed body with the dorsal profile more convex than the ventral profile, particularly anteriorly. The eye is covered by a well-developed adipose eyelid, and the posterior extremity of the jaw is vertically under or past the posterior margin of the eye. The dorsal fin is in two parts, the first consisting of eight spines and the second of one spine followed by 19 to 21 soft rays. The anal fin consists of two anteriorly detached spines followed by one spine and 16 or 17 soft rays. The pelvic fins contain one spine and five soft rays, while the pectoral fins contain 20 or 21 soft rays. The caudal fin is strongly forked, and the pectoral fins are falcate, being longer than the length of the head. The lateral linehas a pronounced and moderately long anterior arch, with the curved section intersecting the straight section midway below the second dorsal fin. The straight section contains 23 to 35 very strong scutes, with bilateral keels present on the caudal peduncle. The chest is devoid of scales with the exception of a small patch of scales in front of the pelvic fins. The upper jaw contains a series of strong outer canines with an inner band of smaller teeth, while the lower jaw contains a single row of teeth. The species has 35 to 42 gill rakers in total and 25 vertebrae are present.
The Crevalle Jack is a popular and highly regarded gamefish throughout its range, with the recreational catch of the species often exceeding commercial catches. The only amateur catch data available are from the US, which has an annual catch of around 400 to 1000 tonnes per year. In Trinidad, the species is the basis for several fishing tournaments. Crevalle Jack are targeted from boats, as well as from piers and rockwalls by land based anglers. Fishermen often target regions where depth suddenly changes, such as channels, holes, reefs or ledges, with strong currents and eddies favourable. The fish take both live and cut baits, as well as a variety of artificial lures; however, when the fish are in feeding mode, they rarely refuse anything they are offered. Popular baits include both live fish, such as mullet and menhaden, as well as dead or strip baits consisting of fish, squid or prawns. Crevalle Jack readily accept any style of lure, including hard-bodied spoons, jigs, plugs and poppers, as well as flies and soft rubber lures. There is some evidence based on long term observations that the species favours yellow lures over all others. Tackle is often kept quite light, but heavy monofilament leaders are employed to prevent the fish's teeth from abrading the line.
The Crevalle Jack inhabits the tropical and temperate waters of the Atlantic Ocean, ranging extensively along both the eastern American coastline and the western African and European coastlines. In the western Atlantic, the southernmost record comes from Uruguay, with the species ranging north along the Central American coastline, and throughout the Caribbean and many of the numerous archipelagos within. The species is found throughout the Greater Antilles, however it is absent from the leeward Lesser Antilles, with its distribution being patchy throughout other Caribbean archipelagos. From the Gulf of Mexico, its distribution extends north along the U.S. coast and as far north as Nova Scotia in Canada, also taking in several northwest Atlantic islands. The Crevalle Jack is also known from Saint Helena Island in the southern Atlantic Ocean.
In the eastern Atlantic, the southernmost record comes from Angola, with the species distributed north along the west African coastline up to West Sahara and Morocco, with its distribution also including much of the Mediterranean Sea. In the Mediterranean, its range extends as far east as Libya in the south and Turkey in the north, and includes most of the northern Mediterranean, including Greece, Italy and Spain. The species' northernmost record in the eastern Atlantic comes from Portugal, with the species also known to inhabit many of the northeastern Atlantic islands, including Cape Verde, Madeira Island, and the Canary Islands.