Tarpons

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Tarpons

Physical characteristics and distribution

Tarpons are large silvery fish, measuring 4-8 ft (1.3-2.5 m) in length, with large scales, a compressed body, a deeply forked caudal fin, and a long ray extending from the dorsal fin. The mouth is large, and contains rows of sharp, fine teeth, and the lower jaw protrudes outward. Tarpon are among the best known and most impressive of the sport fish. They can live in both fresh and saltwater.

Taxonomy

tarpons are the most primitive (i.e., evolutionarily ancient) species classified among the 30 orders of spiny-rayed fish designated as “true” bony fish (superorder Teleosti). Tarpons belong to the order Elopiformes, which includes three families. These are the Elopidae (tenpounders or ladyfish), the Megalopidae (tarpons), and the Albulidae (bonefishes). Some taxonomists place the bonefishes in the order Albuliformes, along with the halosaurs and the spiny eels. The larva (leptocephalus) of fish in the order Elopiformes resembles the larva of eels.

The family Megalopidae includes only one genus, Megalops, and two species of tarpon: Megalops cyprinoides and M. atlanticus. The Megalops cyprinoides lives in the Indian and West Pacific Oceans, from east Africa to the Society Islands. The Megalops atlanticus lives in the western Atlantic Ocean, from North Carolina to Brazil, and also off tropical West Africa.

Physical characteristics and distribution

Tarpons are large fish, measuring up to 8 ft (2.5 m) in length and weighing up to 350 lb (160 kg). Their dorsal and anal fins have an elongated ray, which forms a threadlike projection that trails behind the fish. Tarpons are recognized by their silvery color, forked caudal fin, and underbite caused by an extended jawbone that juts out in front of the upper jaw, giving the fish a turned-down, frowning mouth. Both the upper and lower jaw bones extend well behind the large eyes, and the large mouth, jaws, roof of the mouth, and tongue all have rows of sharp, needlelike teeth.

Tarpons are widely distributed in oceans within their range, and are also found in fresh and brackish water. The swim bladder of tarpons has an open connection with the gullet, and is an adaptation for taking in air. Tarpons are often seen swimming in rivers, canals, and mangrove estuaries. In warm months, tarpons swim north, then return to tropical waters when the weather gets cooler.

Development

tarpons do not mature sexually until they are six or seven years old. A large female tarpon weighing about 140 lb (64 kg) may contain over 12 million eggs. Tarpon spawning sites have not been located, and fresh tarpon eggs have not been seen. However, the females are thought to lay their eggs in shallow seas, or on the ocean floor, starting at the end of June and continuing throughout July and August.

Tarpon larvae (leptocephali) are transparent and shaped like leaves or ribbons, closely resembling eel larvae. Other than having a forked caudal fin, the larvae bear little resemblance to adult tarpons. The larvae of tarpons can be differentiated from eel larvae in that the leptocephali of eels have a rounded tail. Ocean currents carry the tarpon larvae close to shore, to shallow habitats such as marshes, swamps, estuaries, and ponds, where they begin their metamorphosis into young tarpons. They eat smaller fish, crustaceans, and insects.

When tarpons grow large enough to survive without the protection of these shallow-water habitats, they move out of the lagoons into the open sea. Adult tarpons eat fish and crustaceans; one of their favorite foods is the grunion like silverside. Tarpons do not form schools, but they are often found together in bays and canals, since these are the areas where they primarily feed, usually at night. Additionally, groups of tarpons have been seen swimming into schools of small fish and attacking them in unison. The natural enemies of tarpons are sharks and dolphins, and young tarpons have been found in the stomachs of many other species of fish.

Tarpons as game fish

Tarpons are the original big-game fish and are well known to sport fishers throughout the world. Long before fishers began to catch sailfish, marlin, or bluefin tuna for sport, they angled for tarpon. To catch this fish, the angler must be strong, skilled, and have a great deal of endurance.

Fishermen who specialize in catching game fish look for tarpon as far north as Long Island, but they concentrate their efforts in locations where tarpons are known to live more regularly. The best places to catch Megalops atlanticus are in waters surrounding the Florida Keys, off the west coast of Florida, in the Rio Encantado in Cuba, and in the Rio Panuca in Mexico. Megalops cyprinoides is also coveted by sport fishers off the east coast of Africa.

Tarpons are exciting fish to catch because of their tenacious fighting. The instant that the fish is hooked, it hurls itself upward into the air and goes through an astounding series of leaps in an effort to free itself. In fact, this fish can jump as high as 10 ft (3 m) and as far as 20 ft (6 m). These leaps are so violent that, after a while, the tarpon exhausts itself; at this point, it can be brought to the boat.

KEY TERMS

Brackish —Water containing some salt, but not as salty as sea water.

Caudal fin —The tail fin of a fish.

Dorsal fin —A fin located on the back of a fish.

Dorsal ray —A stout filament extending closely above the tarpon’s back, behind its dorsal fin.

Gullet —The throat and esophagus.

Leptocephalus —Mature larva (plural form is leptocephali).

Metamorphosis —A marked change in anatomy and behavior occurring during development.

Tarpons are not often prized as a food fish in North America, because the adults are relatively tough and full of bones. There are exceptions, however. In Mexico and in South America, people eat tarpon salted or smoked. Smaller tarpon are also eaten in Africa. The silvery scales of tarpon are sometimes used to make folk jewelry.