Tarpon, Megalops atlanticus
Tarpon, Megalops atlanticus. Fish caught from coastal waters off Marathon, Florida, July 2018. Length: 40 cm (16 inches). Catch, photograph and identification courtesy of Eli (obsessiveangling.wordpress.com).
Tarpon, Megalops atlanticus. Fish caught from coastal waters off Cape Canaveral, Florida, July 2018. Length: 36 cm (2 feet 2 inches). Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.
Tarpon, Megalops atlanticus. Fish caught from coastal waters off Key West, Florida, March 2017. Length: 1.27 m (4 feet 2 inches). Weight: 12.7 kg (28 lbs). Catch, photograph, and identification courtesy of Dean Kimberly, Atlanta, Georgia.
The Tarpon, Megalops atlanticus, is a member of the Tarpon or Megalopidae Family, that is also known as the Atlantic Tarpon and the Silver King and Mexico as sábalos. It is the only global species in the genus Megalops.
The Tarpon has an oblong, elongated, and strongly compressed body. They are blue-green dorsally and transition to silver on their sides and ventrally. Their caudal and dorsal fins have dusky margins. Their head is short and deep with a straight profile above and a convex profile below. They have large eyes and a large superior mouth oriented upwards with a longer lower jaw and small villiform teeth. They lack fin spines. Their anal fin has 22 to 25 rays and is deep and triangular and with the last ray being slightly elongated in adults; their caudal fin is deeply forked with lobes of equal length; their dorsal fin has 13 to 16 rays and is high anteriorly and with the last ray being elongated; their pectoral fins are long; and, their pelvic fins are large. They are covered with extraordinarily large scales.
The Tarpon is found in coastal waters including estuaries, lagoons, and freshwater rivers at depths up to 30 m (100 feet) with water temperatures between 22oC (72oF) and 28oC (82oF). They reach 2.5 m (8 feet 2 inches) in length and 161 kg (355 lbs) in weight with females being larger than males. As of January 1, 2024, the International Game Fish Association world record stood at 130 kg (287 lbs) with the fish caught in coastal waters off Guinea-Bissau, West Africa in May 2003. They are highly migratory and make long runs to follow water temperatures. They have a high sensitivity to low temperatures and will quickly expire in waters that are less than 10oC (50oF). They form large schools and will frequent the same locations annually. Juveniles consume zooplankton, small crustaceans, and insects. Older juveniles and adults transition to consuming larger crustaceans (shrimp and crab), polychaetes, and schooling fish (anchovies, cichlids, mullets, sardines, and snooks, which they swallow whole). In turn their eggs and larvae are preyed upon by shore birds, small fish, zooplankton and by alligators, porpoises, and sharks as they mature. They can tolerate a wide range of salinities and oxygen concentrations. They have a swim bladder that allows them to gulp atmospheric oxygen, which is essential for their survival and gives them a competitive advantage as they can reside in areas with low predation rates and little competition for prey. Reproduction involves batch spawning and occurs at sea with each female capable of releasing 12,000,000 eggs on average. The eggs hatch quickly and larvae migrate into estuaries. They have a maximum lifespan of eighty years in captivity. Females are known to live longer than males in the wild, fifty-five years versus forty-three years.
The Tarpon is a resident of all Mexican waters of the Atlantic Ocean including the Gulf of Mexico and the Caribbean. They are one of the few species who navigated the Panama Canal and have become established in the Pacific Ocean.
The Tarpon is very easy to recognize and cannot be confused with any other species.
From a conservation perspective, they are currently considered Vulnerable to extinction. Although widely distributed, their populations are believed to have declined by at least 30% over the last decade, which has been attributed to overfishing, habitat degradation, and by-catch mortality. They mature late and have long generation times making their recovery difficult. The Tarpons is considered to be one of the world’s great saltwater game fish due to their size, inshore habitats, fighting abilities (including tremendous endurance which can take 1 to 3 hours to land), long runs, and spectacular airborne leaps when pursued in shallow flats with fly rods. They are considered a marginal food fish due to the abundance of bones and the presence of ciguatoxin, however, they are served for Christmas dinner in some cultures. In Mexico they are retained by subsistence fishermen and sold fresh. They are also retained when caught as a by-catch by commercial fishermen utilizing purse seines, longlines, and gill nets. They are heavily regulated in some areas, including in the United States where most fish are handled as “catch and release.” In Mexico there is a 2 fish per person per day limit without a minimum size requirement, which is poorly communicated and poorly enforced. The International Sábalo Fishing Tournament is held every May in Tecolutla in Mexico’s Costa Esmeralda, Veracruz. They are used by the aquarium trade on a limited basis requiring very large tanks. Their large scales are used in ornamental objects such as artificial pearls.