Latin name

Istiophorus platypterus

Other names

Spindlebeak, bayonetfish; French: voilier, espadon vela; Hawaiian: a’u lepe; Italian: pesce vela, pesce ventaglio; Japanese: bashôkajiki; Portuguese: veleiro, algulhão; Spanish: pez vela, aguja voladora, aguja de faralá, aguja de abanico.

Identification

Body elongated, compressed from sides. Snout in form of elongated, spear-shaped rostrum, round in cross-section. The gill membranes are connected to each other, but free from the intercostal space. The fish is dark blue on top, brownish-blue on the sides, and silvery-white on the belly. The upper jaw is elongated in the shape of a spear. A distinctive feature of this species is the long and high first dorsal fin, consisting of 37-49 elements. It is slate or cobalt blue with many black spots. The second dorsal fin is very little, with six to eight rays. The only prominent lateral line is curved above the pectoral fin, after all it is straight along the midline of the sides. The abdomen is slightly in front of the first anal fin. The flanks often have pale, bluish-gray vertical stripes, rows, or spots. They are easily distinguished by the large, sail-like dorsal fin. Scales change shape as they grow: juveniles have a round plate with a pointed spike in the center; mature specimens have elongated scales in the form of an elongated one- or two-vertical triangle, sparsely arranged on the body and deeply embedded in the skin.

Distribution

They are found worldwide in tropical and temperate waters of the Atlantic, Indian and Pacific Oceans. They are pelagic and migrate in warm coastal waters, although they may migrate to warm coastal areas in some parts of their range. Fish inhabit the eastern Pacific Ocean from Baja California, Mexico, to Peru, and the western Atlantic Ocean from Massachusetts to Brazil. They are most often found in warm waters along the edge of the Gulf Stream.

Habitat

It prefers coastal waters, although it is also known to be caught in the open parts of the oceans. Holoepipelagic oceanic species inhabiting predominantly above the thermocline. It occurs at water temperatures up to 28-30 °C and salinity of 35,2-35,3 %.

Size

The International Game Fish Association (IGFA) has long held sport fishing records for these fish according to their Atlantic and Indo-Pacific distributions. The world record for Atlantic fish is a 141-pound fish caught off the coast of Angola in 1994. Its counterpart in the Pacific Ocean is a 221-pound fish caught off the coast of Ecuador in 1947. Fish from 20 to 50 or 60 pounds are usually caught off the eastern shores of the United States, and fish from 50 to 100 pounds are found in many places in the Pacific. They can exceed 10 feet in length.

Life history and Behavior

Like other pelagic species that spawn in the open sea, sailfish produce large numbers of eggs, perhaps 4 to 5 million. They are fertilized in open water, where they swim with plankton until they hatch. The fish grow quickly and can reach 4-5 feet in length in their first year of life. Their swimming speed reaches 68 miles per hour, making them the fastest fish at short distances. They can form schools or small groups of 3 to 30 individuals, and sometimes move in loose aggregations scattered over a wide area. They feed mainly in the middle layers of water at the edges of reefs or in swirling currents.

Food and feeding habits

They feed on squid, octopus, mackerel, tuna, jacks, herring, char, needlefish, flying fish, mullet, and other small fish. They feed at the surface or in mid-depth. The food composition varies greatly depending on the habitat, but squid and fish predominate in the food spectrum of the sailfish.

Reproduction

Apparently, spawning in tropical waters occurs year-round, with a peak in summer of the respective hemisphere. In the western Pacific, the largest number of postlarvae and sexually mature specimens is found in the Kuroshio Current and increases during the spawning season. Individuals greater than 160 cm in length (from the eye to the fork of the caudal fin) migrate to the southern part of the East China Sea to spawn. In the East Pacific, the spawning season is determined by the position of the 28 °C isotherm of the water surface. In the Indian Ocean, off East Africa, spawning begins when the temperature of coastal waters influenced by the East African Coastal Current reaches 29-30 °C and salinity reaches 35.2-35.3%. At the same time, the highest biological productivity of surface waters is observed in an area of the junction of branches of the Somali Current, following the southward direction, and the East African Coastal Current, directed to the north. In the Sea of Japan, spawning peaks in late summer and early fall. Fish form pairs to spawn, sometimes two or three males chase one female. The fecundity of sailfish in the eastern Pacific is 1.8-5.1 million eggs. In the Pacific Ocean, ovarian eggs have a maximum diameter of about 0.85 mm, a single fat blob of pale yellow color: the shell without clearly visible structures is completely transparent. In the Indian Ocean, the largest ovarian egg diameter of one of the females caught was about 1.3 mm. Larvae have a tall head, strong, backward pointing upper and lower spines, long pelvic fins, long and high first dorsal fin, and diffuse body pigmentation.