Tuna, a large marine food and game fish. The tuna, sometimes called tunny, has been used as food for over 3,000 years. Sportsmen consider it one of the best game fish.

TunaTuna live in schools and often migrate great distances.

Tuna are fast swimmers and are capable of bursts of speed of up to 55 miles per hour (89 km/h). They live in schools and often migrate great distances. Tuna maintain a body temperature higher than the temperature of the surrounding water. Some species live in northern seas as cold as 40° F. (4° C.); other species of tuna live in tropical waters as warm as 85° F. (29° C.). Tuna swim at different depths, depending on the water temperature.

Tuna have streamlined bodies and powerful, deeply forked tails. They range in size from less than 10 pounds (4.5 kg) to more than 1,500 pounds (680 kg). Tuna feed on smaller fish, squid, and crustaceans. Their only natural predators are mako sharks and killer whales. The female lays 1 million to 30 million eggs. The offspring mature in 3 to 5 years. Members of some species can live to be about 35 years old.

Kinds of Tuna
The Albacore, or Long-fin Tuna

can weigh up to 90 pounds (41 kg) and grow to about 4 feet (1.2 m) long. The upper parts are steel blue, the sides and underparts silvery with an iridescent sheen. Albacore are sought by both commercial and sports fishermen.

The Bluefin Tuna, or Horse Mackerel

is one of the largest marine game fish and can measure more than 11 feet (3.4 m) in length. It is dark steel blue with a green sheen above, blending to silvery gray on the undersides. The bluefin can weigh up to about 1,500 pounds (680 kg); it commonly reaches a weight of more than 650 pounds (295 kg). It is one of the strongest and most active game fish.

The Yellowfin Tuna, or Allison Tuna

is the most brilliantly colored of all the tuna. It has golden-yellow stripes on its upper sides and predominantly yellow fins. Most adult specimens weigh from 20 to 120 pounds (9 to 54 kg), but some weigh 400 pounds (181 kg). They can reach a length of more than six feet (1.8 m). The yellowfin tuna is very important commercially and is the mainstay of the California-based tuna-fishing fleet.

Other Tuna

The blackfin tuna is found only in the western Atlantic from Cape Cod to Brazil. It usually weighs less than 10 pounds (4.5 kg). The skipjack and bigeye tuna are also commercially important species, especially in the Pacific. The little tuna, black skipjack, and wavyback skipjack are popular game fish.

The Tuna Industry

Japan accounts for about one-half of the world tuna catch; the United States, about one-fourth. Other important tuna-fishing countries are France and Italy.

Tuna is one of the most important food fish of the United States. Almost all of the American catch is canned, primarily in California. The most important fishing areas in the United States are along the west coast; about half of the United States catch is yellowfin tuna.

Five species of tuna are most important commercially: the yellowfin, skipjack, albacore, bigeye, and bluefin. In the United States, the albacore is the only tuna whose meat can legally be labeled “white-meat tuna.” White-meat tuna is especially desirable and is more costly than other kinds, which are simply labeled “tuna.” Tuna are caught primarily by traps, trolling, long lines, and purse seines. Several fish farms on the east coast of the United States and Canada raise tuna commercially.

Tuna belong to the family Scombridae. The albacore is Thunnus alalunga; the Atlantic bluefin tuna, T. thynnus; the yellowfin tuna, T. albacares; the bigeye tuna, T. obesus; the blackfin tuna, T. atlanticus; the skipjack tuna, Katsuwonus pelamis.