Blue Runner, Hard Tail Jack, Runner
Cojinuda Negra
(Caranx crysos)

Blue Runner, Caranx crysos: The Blue Runner is a common fish species found in the western Atlantic from Brazil to Canada. They reach a maximum length of 70 cm (28 inches) and 5.0 kg (12 pounds) but are more common below 35 cm.

They are characterized by an overall “jack-like” appearance, with an aerodynamically slender body, exceedingly strong prominent scutes and branched lateral line, extraordinarily long pectoral fins, blue-green back with silver-gray to golden below, and a characteristic black spot one-quarter of the way down its gill cover.

Upon collection they have a series of seven narrow pale vertical bars spaced about 1 inch apart along the sides that quickly fade.

They are identical in appearance and morphology to the Green Jack, Caranx caballus, found only in the Pacific Ocean, with the exception is that they have 35 to 42 gill rakers versus 41 to 45 for the Green Jack.

The Blue Runner inhabits both inshore and offshore environments between the surface and 300 feet in the water column, and are found predominately over reefs or around large man made offshore structures such as buoys, ship wrecks and oil platforms. They are a schooling predatory fish attacking schools of small fish in-shore, various crustaceans and other invertebrates and feed exclusively on zooplankton off-shore.

Blue runner schools can reach up to 10,000 individuals in size. In North and South America they are caught at a level of 5,000 tons per year taken by haul seines, lampara nets, purse seines, gill-nets, and hook and line methods and sold either fresh, dried, smoked or as fishmeal, oil or bait.

They are a targeted light tackle recreational gamefish. They are also used as a live bait fish for big game fish (billfish, cobia and amberjack) as they are very hardy in the bait well and can swim surprisingly fast for long distances on the hook.

Blue Runners are viewed as mediocre table faire with the larger species known to carry ciguatera toxin. They are well studied scientifically due to high abundance in the Atlantic, its importance to various fisheries and to the ecology of its environment. They are preyed upon by many larger species including fishes, birds and dolphins. On average each female releases between 40,000 and 1.5 million pelagic eggs. The oldest known individual was 11 years old.

The Blue Runner is a member of the Carangidae or Jack family which are known in Mexico as Jureles. The Jacks are found in all tropical and subtropical seas, with 140 individual species having been identified to date. They are voracious predators feeding primarily on small fishes. They frequently travel in large schools and roam considerable distances, normally following schools of smaller bait fish. They are generally silver in color, and exhibit a wide range in size from about 10 inches and 1 pound, to 6 feet and 90 pounds. The Jacks are powerful mid-water swimmers characterized by their streamlined, aerodynamic shape, with a latterly compressed body, slender tail base and deeply forked caudal fin. The posterior scales of the lateral line are modified into spiny, plate-like structures known as scutes (see juvenile Big Eye Trevally photo). Many Jacks have elongated rays extending from their dorsal and anal fins (see juvenile African Pompano or Roosterfish photos). Jacks spawn pelagically, releasing large numbers of tiny buoyant eggs that travel the globe, carried by currents. Most Jacks are esteemed as food fishes and are targeted by both commercial and sport fishermen. Jacks are found over rocky structure, along the edge of reefs and adjacent to large “drop-offs.”

Blue Runner picture

Blue Runner, Caranx crysos: Commercial fish courtesy of the Ranch 99 Market, San Diego, Calif., in May 2011. Size 34 cm (13.3 inches). Description and photo courtesy of John Snow.