Marlin (Istiophoridae) is a family of fishes of the order Perciformes. 3 genera - Istiophorus, Makaira, Tetrapturus. 11 species. The snout is elongated, round in cross-section. There are pelvic fins. The first dorsal fin is high and long, the second is short. Large marine, pelagic fish, active swimmers. Dwell in tropical waters of the Pacific, Indian and Atlantic Oceans. Make long migrations. Predators. Feed on squid, fish. Length up to 5 m, weight up to 900 kg. Marlin - valuable commercial fish. Objects of sport fishing.
The family unites large pelagic fish, common in warm seas and characterized by a powerful elongated body and lance-shaped pointed elongated upper jaw. This "spear", almost rounded in cross-section and having a rough terkovidnoy surface, never reaches as long as the flattened and smooth to the touch sword sword swordfish. The body is covered with small oblong scales, entirely hidden in the skin. The pelvic fins contain one to three rays. The dorsal fin is divided into two parts - the main one, which has a long base and barbed rays at the beginning, and a short additional one located on the caudal stem (in young fish fin undivided); the anal fin also consists of a lobed anterior and a small posterior part. On the sides of the caudal stem on each side there are two muscular keels, caudal fin sickle-shaped with very thin but strong blades. The jaw teeth are rather poorly developed.
Marlin belong to a group of active predators, developing in the water a huge speed, which can reach 100-130 km / hr. Fast swimming is greatly facilitated by the external structure of these fish. Their "spear" serves to turbulize the oncoming flow and greatly reduces drag when moving in dense water environment, and tail keels increase the transverse rigidity of the tail stem and perform the same role of horizontal stabilizers (some marlins serve the same purpose rigid pectoral fins). It is interesting to note that technical thought has reproduced quite similar devices in aircraft designs, also having a pointed nose and tail stabilizers.
Representatives of this family are especially characteristic of the upper pelagic layers of tropical and subtropical seas and oceans, but in pursuit of their prey, they may visit deeper layers. Some species also penetrate moderately warm waters during the warm season.
All Marlin have flavorful and highly prized meat and serve as an intensive fishery.