sailfish

(click to enlarge)
Sailfish (Istiophorus platypterus) (credit: D. Corson/Shostal Associates)

Valued food and game fish in the genus Istiophorus (family Istiophoridae) of warm and temperate waters worldwide. It has a long, rounded spear extending from its snout but is distinguished from marlins and related species by its slimmer form, long pelvic fins, and especially its large, sail-like dorsal fin, which is bright blue and spotted. Deep blue above and silvery below, they grow to about 11 ft (3.4 m) long and 200 lbs (90 kg) or more. They feed mainly on other fishes. Its classification is uncertain, and one (I. platypterus) to several species may be recognized.

For more information on sailfish, visit Britannica.com.

Istiophorus platypterus

FAMILY

Istiophoridae

TAXONOMY

Istiophorus platypterus (Shaw, 1792), Indian Ocean. Some authors, such as Nakamura (1985), differentiate the Atlantic sailfish, I. albicans (Latreille, 1804), as a separate species.

OTHER COMMON NAMES

French: Voilier; Spanish: Pez vela.

PHYSICAL CHARACTERISTICS

Sailfishes reach a maximum size of approximately 11 ft (3.5 m) total length and 220 lb (100 kg). Body fairly compressed. Two dorsal and two anal fins, the first dorsal fin sail-like and remarkably higher than greatest body depth, with 42–49 rays. Second dorsal fin with six or seven rays, slightly posterior to second anal fin which also has six or seven rays. Pectoral fins moderate, 18–20 rays. Pelvic fins extremely long, almost reaching the anus, depressable into a groove, with one spine and several rays tightly fused together. Jaws and palatine bones with small, file-like teeth. Gill rakers absent. Left and right branchiostegal membranes broadly united. Vertebrae, 24. Swim bladder made up of many small bubble-shaped chambers.

DISTRIBUTION

Most researchers consider the sailfish to be a single pantropical species occurring in all three major oceans.

HABITAT

An epipelagic and oceanic species, usually found above the thermocline. Sailfishes have a strong tendency to approach continental coasts, islands, and reefs.

BEHAVIOR

Sailfishes occasionally form schools or smaller groups of 3–30 individuals, but more often occur in loose aggregations over a wide area.

FEEDING ECOLOGY AND DIET

Feeding behavior has been observed by fishermen: One or several sailfish locate a school of prey fish (such as sardines, anchovies, mackerel, or jack mackerel) and pursue the school at half speed with their fins half-folded back into the grooves. They then drive at the prey at full speed with fins completely folded back and make sharp turns with fins expanded to confront part of the school and strike the prey with their bills. They feed on the killed or stunned fish, usually head first as well as on a variety of fishes, crustaceans, and squid.

REPRODUCTIVE BIOLOGY

Spawning occurs with males and females swimming in pairs or with two or three males chasing one female. Sailfishes spawn throughout the year in tropical and subtropical waters with peak spawning in local summer seasons. Ripe ovarian eggs are approximately 0.03 in (0.85 mm) in diameter and have a single oil globule. Eggs shed from a captured female averaged 0.05 in (1.30 mm) in diameter.

CONSERVATION STATUS

Not threatened.

SIGNIFICANCE TO HUMANS

Sailfishes are often taken as bycatch by the commercial surface tuna long liners. United Nations Food and Agriculture Organization (FAO) catch statistics for 1991–2000 show catches of 11.1–23.7 thousand tons (10.1–21.5 thousand metric tons) per year by 42 countries. Sailfishes are primarily important as a sportsfish taken by trolling at the surface. The all-tackle gamefish record is a 221-lb (100.2-kg) fish taken off Santa Cruz Island, Ecuador.

This article is about the fish. For the submarines, see USS Sailfish.

Sailfishes Fossil range: 14–0 Ma PreЄ Є O S D C P T J K Pg N Middle Miocene to Present[1]
Indo-Pacific sailfish, Istiophorus platypterus
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Perciformes
Family:	Istiophoridae
Genus:	Istiophorus Lacépède, 1801
Species:	I. albicans, I. platypterus
Binomial name
Istiophorus albicans, Istiophorus platypterus Latreille, 1804, Shaw, 1792

Sailfish are two species of fishes in the genus Istiophorus, living in warmer sections of all the oceans of the world. They are blue to grey in color and have a characteristic erectile dorsal fin known as a sail, which often stretches the entire length of the back. Another notable characteristic is the elongated bill, resembling that of the swordfish and other marlins. They are therefore described as billfish in sport fishing circles.

Both species of sailfishes grow quickly, reaching 1.2-1.5 m (4-5 ft) in length in a single year, and feed on the surface or at mid-depths on smaller pelagic forage fish and squid. Individuals have been clocked at speeds of up to 110 km/h (70 mph), which is the highest speed reliably reported in a fish.^[2] Generally, sailfish do not grow to more than 3 m (10 ft) in length and rarely weigh over 90 kg (200 lb).

The sail is normally kept folded down and to the side when swimming, but it may be raised when the sailfish feels threatened or excited, making the fish appear much larger than it actually is. This tactic has also been observed during feeding, when a group of sailfish use their sails to "herd" a school of fish or squid.

Sailfish are highly prized game fish and are known for their incredible jumps. The sailfish also turns its body light blue with stripes when excited, confusing some fish and making it easier to catch prey.

Contents 1 Species 2 Gallery 3 References 4 External links

Species

• Atlantic sailfish (Istiophorus albicans).
• Indo-Pacific sailfish (Istiophorus platypterus).

Gallery

Sailfish caught off Quepos, Costa Rica

Sailfish caught off Quepos, Costa Rica

Sailfish caught off Quepos, Costa Rica

Sailfish caught off Quepos, Costa Rica

References

1. ^ Sepkoski, Jack (2002). "A compendium of fossil marine animal genera". Bulletins of American Paleontology 364: p.560. http://strata.ummp.lsa.umich.edu/jack/showgenera.php?taxon=611&rank=class. Retrieved 2008-01-08. 
2. ^ Haulin' Bass - elasmo-research.org. Accessed March 19, 2008

• Species of Istiophorus. FishBase. Ed. Ranier Froese and Daniel Pauly. March 2008 version. N.p.: FishBase, 2008.

External links

Wikimedia Commons has media related to: Istiophorus

• Sailfish Pictures
• Images from National Geographic
• Pacific Sailfish information and pictures from Pacific Fins - Guatemala
• Costa Rica Sailfish Fishing

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