Blue Runner, Caranx crysos

Blue Runner, Caranx crysos, Juvenile. Fish caught from coastal waters off Long Island, New York, September 2023. Length: 13 cm (5.2 inches). Catch, photograph and identification courtesy of Aidan Perkins, Long Island, New York.

Blue Runner, Caranx crysos. Fish caught off the Gulf Shores Pier, Gulf Shores, Alabama, June 2023. Length: 20 cm (7.9 inches). Catch, photograph, and identification courtesy of Chris Moore, Peoria, Arizona.

Blue Runner, Caranx crysos. Fish caught from coastal waters off San Juan, Puerto Rico, December 2013. Length: 22 cm (8.7 inches). Catch, photograph, and identification courtesy of Josh Leisen (joshadventures.com), Gaylord, Michigan.

Blue Runner, Caranx crysos. Fish caught from coastal waters off Key West, Florida, August 2014. Length: 33 cm (13 inches). Catch and photograph courtesy of Dean Kimberly, Atlanta, Georgia.

Blue Runner, Caranx crysos. Fish caught from coastal waters off the Dominican Republic, February 2017. Length: 34 cm (13 inches). Catch and photograph courtesy of David Haselbauer, Scandia, Minnesota.

Blue Runner, Caranx crysos. Fish caught off the Dania Beach Pier, Dania Beach, Florida, April 2019. Length: 34 cm (13 inches). Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.

Blue Runner, Caranx crysos. Fish caught from coastal waters off Deerfield Beach, Florida, December 2020. Length: 38 cm (15 inches). Catch, photograph and identification courtesy of Ben Cantrell, San Diego, California.

The Blue Runner, Caranx crysos, is a member of the Jack or Carangidae Family, that is known in Mexico as cojinuda negra. Globally, there are seventeen species in the genus Caranx, of which nine are found in Mexican waters, three in the Atlantic, five in the Pacific and one in both the Atlantic and the Pacific Oceans.

The Blue Runner has a “jack-like” moderately compressed relatively slender rectangular body with a depth that is 26% to 30% of standard length. They have an overall light olive to dark blue-green coloration and are silvery to golden ventrally. They have 7 pale narrow vertical bars spaced about 1 inch apart along their sides that fade quickly upon collection. Their head profile is convex with a gentle slope. They have 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 half-way between their pectoral fin base and the end of their lateral line. All their fins are pale. Their anal fin has 2 spines followed by 1 spine and 19 to 21 rays with a raised front lobe; their caudal fin has a slender base and is strongly forked; their first dorsal fin has 8 spines with a raised lobe; their second dorsal fin has 1 spine and 19 to 21 rays; and, their pectoral fins and longer than their head. They have 10 to 14 gill rakers on the upper arch and 25 to 28 gill rakers on the lower arch. Their pronounced lateral line has a short anterior arch and 46 to 56 strong prominent scutes.

The Blue Runner is a pelagic schooling species found both inshore and offshore over reefs and around large man-made offshore structures between the surface and depths of 91 m (300 feet). Schools can reach up to 10,000 individuals in size. They reach a maximum of 70 cm (2 feet 4 inches) in length and 5.0 kg (11 lbs 0 oz) in weight. As of January 1, 2024, the International Game Fish Association world record stood at 5.05 kg (11 lbs 2 oz) with the fish caught in coastal waters off Dauphin Island, Alabama in June 1997. They are predatory fish that attack schools of small fish inshore and also consume various crustaceans and other invertebrates. They feed exclusively on zooplankton offshore. They are preyed upon by many larger species including birds, dolphins, and fish. Each female releases an average of 40,000 to 1,500,000 pelagic eggs annually. Due to their high abundance in the Atlantic they are well studied scientifically and their importance to various fisheries and the ecology of their environment are well understood. They have lifespans of up to eleven years.

The Blue Runner is a resident of all Mexican waters of the Atlantic Ocean including the Gulf of Mexico and the east coast of the Yucatán Peninsula in the Caribbean.

The Blue Runner is very similar in appearance and morphology to the Green Jack, Caranx caballus (41-45 gill rakers), which is only found in the Pacific Ocean and its head profile is slightly wider at the eyes (17% to 18% of standard length versus 15% to 16% for the Green Jack).

From a conservation perspective the Blue Runner is currently considered to be of Least Concern with stable, widely distributed populations. In North and South America, they are fished commercially in North and South America with gill nets, haul seines, lampara nets, purse seines, and hook and line and taken at the level of 5,000 tons per year. They are sold for human consumption fresh, dried, or smoked. They are used in fish meal. They are also utilized as a live bait fish targeting amberjack, billfish, or cobia as they are very hardy and can swim surprisingly fast for long distances on the hook. They are also a targeted species of recreational anglers. They are viewed as mediocre table fare as larger specimens are known to contain ciguatoxin. The Blue Runner has been bred in captivity for the aquarium trade.