Bluefin Trevally, Caranx melampygus
The Bluefin Trevally, Caranx melampygus, whose common Spanish name is jurel aleta azul, is a member of the Jack or Carangidae Family, known collectively as jureles and pámpanos in Mexico. Globally, there are seventeen species in the genus Caranx, nine of which are found in Mexican waters, three in the Atlantic and five in the Pacific and one in both oceans.
The Bluefin Trevallies have “jack-like” moderately compressed deep oblong bodies 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 and dorsal fins have elongated front lobes and their pectoral fins are disproportionately long. They have 17 to 21 gill rakers and 27 to 42 strong scutes. Their lateral line has a pronounced anterior arch. Their body is covered with small scales.
The Bluefin Trevallies are found in reefs at depths up of 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 length of 1.17 meters (3 feet 10 inches). 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.
In Mexican waters the Bluefin Trevally has a very limited range being found in the only in the southern extreme of the Sea of Cortez of the Pacific. 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 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).
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 Trevallies are a popular and prized game fish for recreational anglers. They are also considered excellent food fish. Efforts are currently ongoing in Hawaii to raise this species via aquaculture.
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. Fish caught off the beach at Cabo Real, Baja California Sur, March 2014. Length: 36 cm (14 inches).
Bluefin Trevally, Caranx melampygus. Underwater photo taken in coastal waters off Kailua-Kona, HI, November, 2015. Length: 36 cm (14 inches). Photo courtesy of Bob Hillis, Ivins, UT.