Bluefin Trevally, Caranx melampygus

Bluefin Trevally, Caranx melampygus, Juvenile. Fish caught with a cast net off Palmilla Beach, Baja California Sur, March 2015. Length: 11.2 cm (4.4 inches). Catch courtesy of Mauricio Correa, San José del Cabo, Baja California Sur.

Bluefin Trevally, Caranx melampygus, Juvenile. Fish provided by the commercial bait salesmen of Puerto Los Cabos, Baja California Sur, November 2008. Length: 15.0 cm (5.9 inches).

Bluefin Trevally, Caranx melampygus, Juvenile. Fish caught from coastal waters off Puerto Los Cabos, Baja California Sur, November 2007. Length: 18 cm (7.1 inches). Identification courtesy of Dr. Ross Robertson, Smithsonian Tropical Research Institute, Panama and Dr. William Smith-Vaniz, Florida Integrated Science Center, Gainesville, Florida.

Bluefin Trevally, Caranx melampygus, Juvenile. Fish caught from coastal waters off Kona, Hawaii, March 2021. Length: 24 cm (9.4 inches). Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.

Bluefin Trevally, Caranx melampygus. Fish caught off the beach at Cabo Real, Baja California Sur, March 2014. Length: 36 cm (14 inches).

Bluefin Trevally, Caranx melampygus. Fish caught from coastal waters off Kona, Hawaii, March 2021. Length: 36 cm (14 inches). Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.

Bluefin Trevally, Caranx melampygus. Fish caught from coastal waters off Honolulu, Hawaii, April 2021. Length: 72 cm (2 feet 4 inches). Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.

Bluefin Trevally, Caranx melampygus. Fish caught from shore on the west side of Isla Cerralvo, Baja California Sur, September 2000. Photograph courtesy of Bill Mathias, La Paz, Baja California Sur.

Bluefin Trevally, Caranx melampygus. Underwater photograph taken in coastal waters off Kailua-Kona, Hawaii, November 2015. Photograph courtesy of Bob Hillis, Ivins, Utah.

The Bluefin Trevally, Caranx melampygus, is a member of the Jack or Carangidae Family, that is also known as the Bluefin Crevalle Jack and in Mexico as jurel aleta azul. Globally, there are seventeen species in the genus Caranx, of which nine are found in Mexican waters, three in the Atlantic and five in the Pacific and one in both the Atlantic and Pacific Oceans.

The Bluefin Trevally has a “jack-like” moderately compressed deep oblong body with a depth that is 33% to 37% of standard length. Their head and body are bronze in color with a blue tinge. They are covered with small black dots from their mid-section to their rear. Their anal, caudal, and second dorsal fins are electric blue. The pectoral fins of juveniles are yellow. They have an angular head profile. Their anal fin has 2 spines followed by 1 spine and 17 to 20 rays with an elongated front lobe; their caudal fin has a slender base and is deeply forked; their first dorsal fin has 8 spines and an elongated front lobe; their second dorsal fin has 1 spine and 21 to 24 rays; and, their pectoral fins are disproportionately long and longer than the head. They have 5 to 9 gill rakers on the upper arch and 17 to 21 gill rakers on the lower arch. Their body is covered with small scales.Their lateral line has a pronounced anterior arch with 27 to 42 strong scutes.

The Bluefin Trevally is found in reefs at depths up of 229 m (750 feet). Adults are found in deep water whereas juveniles are found seasonally in large numbers in shallow sandy inner flat environments and are known to enter estuaries. They reach a maximum of 1.17 m (3 feet 10 inches) in length. As of January 1, 2024, the International Game Fish Association world record for length stood at 78 cm (2 feet 7 inches) with the fish caught from coastal waters off Panama in May 2012. The corresponding world record for weight stood at 13.24 kg (29 lbs 3 oz) with the fish caught in coastal waters off Clipperton Island in April 2012. They travel as solitary individuals or in small schools. They are opportunistic predators feeding on benthic and pelagic fish as well as squid and crustaceans. The Bluefin Trevally is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, growth, longevity, movement patterns, diet, habitat use, and reproduction.

The Bluefin Trevally is a resident of Mexican waters of the Pacific Ocean, however it has a very limited range being found in the only in the southern extreme of the Sea of Cortez. I have a fish in my possession that was caught 40 miles north of Cabo San Lucas along the southwest coast of Baja establishing a northerly range extension for this species.

The Bluefin Trevally can be confused with the Black Jack, Caranx lugubris (all fins gray-black), the Golden Trevally, Gnathanodon speciosus (yellow fins; large dark spots on sides), and the Island Jack, Carangoides orthogrammus (six oval yellow spots on sides).

From a conservation perspective the Bluefin Trevally is currently considered to be of Least Concern with stable, widely distributed populations. In some parts of the Eastern and Central Pacific and the Indian Ocean (including the eastern, northern, and western coastal waters of Australia), the Bluefin Trevally is a popular and prized game fish for recreational anglers. They are also fished commercially and marketed fresh and frozen. They are considered to be an excellent food fish. Efforts are currently ongoing in Hawaii to raise this species via aquaculture.