Blue Runner

The blue runner is moderately large in size, growing to a maximum confirmed length of 70 cm and 5.05 kg in weight, but is more common at lengths less than 35 cm. The blue runner is morphologically similar to a number of other carangids, having an elongated, moderately compressed body with dorsal and ventral profiles of approximately equal convexity and a slightly pointed snout. The posterior section of the eye is covered by a moderately well developed adipose eyelid, and the posterior extremity of the jaw is vertically under the center of the eye. The dorsal fin is in two parts, the first consisting of eight spines and the second of one spine followed by 22 to 25 soft rays. The anal fin consists of two anteriorly detached spines followed by one spine and 19 to 21 soft rays. The pectoral fins become more falcated with age, having 21 to 23 rays, and are slightly longer than the head.

The blue runner is extensively distributed throughout the tropical and temperate waters of the Atlantic Ocean, ranging widely along both the eastern American coastline and the western African and European coastlines. In the western Atlantic, the species' southernmost record comes from Maceio, Brazil, with the species ranging north along the Central American coastline, and throughout the Caribbean and the numerous archipelagos throughout. 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 north-west Atlantic islands. The blue runner is also present on several central Atlantic islands, making its distribution Atlantic-wide.

The blue runner is a fast-swimming predator, which primarily takes small, benthic fishes as prey in inshore waters. Studies on the species' diet on both side of the Atlantic have shown similar results. A Puerto Rican study found the species supplements its fish-dominated diet with crabs, shrimp, copepods, and other small crustaceans. More detailed research in Cape Verde found as well as fish, blue runner take shrimp, prawns, lobsters, jellyfish, and other small invertebrates. The diet of juveniles is more zooplankton-dominated, with young fish predominantly taking cyclopoid and calanoid copepods, and gradually moving to a more fish-based diet.

The blue runner reaches sexual maturity at slightly different lengths throughout its range, with all such studies occurring in the west Atlantic. Research in northwest Florida found a length at maturity of 267 mm, a study in Louisiana showed the species reaches sexual maturity at 247–267 mm in females and 225 mm in males, and in Jamaica lengths of 260 mm for males and 280 for females were estimated. Spawning appears to occur offshore year round, although several peaks in spawning activity have been found in different areas through the species range. Peak spawning season in the Gulf of Mexico occurs from June to August, with a secondary peak in spawning during October in northwest Florida. Elsewhere, peaks in larval abundance indicate spawning in the warmer summer months. Each female releases between 41,000 and 1,546,000 eggs on average, with larger fish producing more eggs.

The blue runner is a highly important species to commercial fisheries throughout parts of its range. Due to its abundance, it may be one of the primary species in a fishery. The availability of fisheries statistics for the species is variable throughout its range, with the Americas having separate statistics kept for the species, while in Africa and Europe, it is lumped in with other carangids in statistics. In the Americas, recent catch data suggests an increased amount of the species is being taken (or reported), with the 2006 and 2007 catch averaging between 6000 and 7000 tonnes, while during the 1980s and 1990s, the annual catch was rarely greater than 1000 tonnes. Research on the fisheries of local regions has shown how important the fish is to certain fisheries.