Indo-Pacific sailfish (Istiophorus platypterus)

Description

What’s the World’s Favourite Species?

Indo-Pacific sailfish fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Indo-Pacific sailfish description

With its huge, sail-like dorsal fin, long, pointed bill, and graceful, elongated body, the Indo-Pacific sailfish (Istiophorus platypterus) is one of the world’s most charismatic fish species ⁽³⁾. The body colouration is predominantly metallic blue, darker on the upperparts and lighter on the sides, with around 20 bluish vertical bars along the flanks, along with diffuse brown markings ^{(2) (3)}. The underparts are silvery white, while the sail-like first dorsal fin is darker blue, and marked with scattered small, dark, round spots ⁽³⁾. This striking fin is erectile, and provides stability when raised, but can be flattened into a groove along the back to reduce drag during bursts of speed. The Indo-Pacific sailfish’s additional fins are also distinctive, with slender, pointed pectoral fins, and a large, crescent-shaped caudal fin ⁽⁴⁾. The jaws of the Indo-Pacific sailfish extend into a slender bill, the upperpart of which is extremely long and bears a number of small, file-like teeth on the lower surface ^{(4) (5)}.

Also known as

bayonet fish, sailfish.

French

Empereur Éventail, Espadon Voilier.

Spanish

Aguja de Abanico, Pez Velo, Picudo Banderón.

Size

Maximum length: 340 cm ⁽²⁾

Maximum weight: 100 kg ⁽³⁾

Indo-Pacific sailfish biology

The Indo-Pacific sailfish is capable of tremendous bursts of speed over short distances, making it one of the fastest—if not the fastest—of all fish species. Tests in the 1920s estimated that this species is capable of short sprints of up to 111 kilometres per hour, although more conservative estimates of 37 to 55 kilometres per hour are more commonly accepted ⁽⁴⁾. An opportunistic predator, the Indo-Pacific sailfish takes a variety of food items, including fish, crustaceans and cephalopods, but its most common source of prey is schooling fishes, such as sardines, anchovies and mackerel ^{(2) (3) (5)}. This species typically hunts alone, although groups have also been known to display cooperative feeding behaviour. When feeding upon schooling fish, the Indo-Pacific sailfish herds the shoal into a dense group called a ‘bait ball’ before swimming through the middle and making thrashing movements with head. The resulting impact with the sailfish’s bill kills or stuns large numbers of fish, which are then picked off as they sink through the water column ⁽²⁾. The fully grown Indo-Pacific sailfish has few natural predators, and while large sharks and killer whales have been known to prey on individuals hooked by longlines, predation on free-swimming specimens is likely to be rare ⁽²⁾.

The Indo-Pacific sailfish’s reproductive behaviour involves the male and female swimming in pairs, or several males chasing a single female, prior to spawning taking place. The female produces huge numbers of eggs, which hatch into tiny larvae, and develop the sail-like dorsal fin and elongated bill when only five centimetres long ⁽⁴⁾.

The Indo-Pacific sailfish spawns throughout the year in tropical and subtropical waters, with peak spawning taking place during the summer ⁽³⁾. Populations in the Pacific undergo seasonal spawning migrations, covering extremely large distances ^{(2) (3)}.

Indo-Pacific sailfish range

As its name suggests, this species occupies the Indo-Pacific, occurring in both tropical and temperate waters. Individual Indo-Pacific sailfish have also entered the Mediterranean Sea from the Red Sea, via the Suez Canal ⁽³⁾.

Indo-Pacific sailfish habitat

The Indo-Pacific sailfish typically occurs in warm surface waters, but can be found to depths of 200 metres. While this species has an oceanic distribution, populations are densest around coasts and islands ⁽³⁾.

Indo-Pacific sailfish status

The Indo-Pacific sailfish is classified as Least Concern (LC) on the IUCN Red List ⁽¹⁾.

Indo-Pacific sailfish threats

The Indo-Pacific sailfish is fished by both commercial fisheries and sport anglers, and also taken as bycatch by commercial tuna longliners ⁽²⁾.While this species has a high reproductive output ⁽⁴⁾, its population is likely to have been affected by overexploitation ⁽⁶⁾.

Indo-Pacific sailfish conservation

Conservation organisations such as the Billfish Foundation are playing a vital role in promoting sustainable fishing practices for the Indo-Pacific sailfish and other species of billfish worldwide ⁽⁶⁾. Although this species is a highly popular gamefish, sport fishing is well regulated in most areas, and returning hooked fish to the water is widely practiced ⁽⁴⁾. Indeed, anglers and scientists are working in concert to learn more about this species by tagging recreational catches and reporting them to a central database ^{(4) (6)}. In addition, conservationists, and an increasing number of sport anglers, are discouraging the serving of sailfish meat in restaurants ⁽⁴⁾.

Environment Agency - Abu Dhabi is a principal sponsor of ARKive. EAD is working to protect and conserve the environment as well as promoting sustainable development in the Emirate of Abu Dhabi.

View information on this species at the UNEP World Conservation Monitoring Centre.

Find out more

Find out more about conservation of the Indo-Pacific sailfish and other billfish species: 

• The Billfish Foundation:
  www.billfish.org

Authentication

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk

Glossary

Bycatch

In the fishing industry, the part of the catch made up of non-target species.

Caudal fin

The tail fin of a fish.

Cephalopod

From the Greek for ‘head-foot’, a class of molluscs that occur only in marine habitats. All species have grasping tentacles, and either an internal or external shell. Includes nautiloids, cuttlefish, squids, octopuses, and extinct ammonites and belemnites.: from the Greek for ‘head-foot’, a class of molluscs that occur only in marine habitats. All species have grasping tentacles, and either an internal or external shell. Includes nautiloids, cuttlefish, squids, octopuses, and extinct ammonites and belemnites.

Crustaceans

Diverse group of arthropods (a phylum of animals with jointed limbs and a hard chitinous exoskeleton) characterised by the possession of two pairs of antennae, one pair of mandibles (mouthparts used for handling and processing food) and two pairs of maxillae (appendages used in eating, which are located behind the mandibles). Includes crabs, lobsters, shrimps, woodlice and barnacles.

Dorsal fin

The unpaired fin found on the back of the body of fish, or the raised structure on the back of most cetaceans.

Larvae

Stage in an animal’s lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.

Pectoral fins

In fish, the pair of fins that are found one on each side of the body just behind the gills. They are generally used for balancing and braking.

Spawning

The production or depositing of large quantities of eggs in water.

References

1. IUCN Red List draft assessments (July, 2011)
   http://sci.odu.edu/gmsa/about/tunas_billfishes.shtml
2. Nakamura, I. (1985) FAO species catalogue. Vol. 5. Billfishes of the world. An annotated and illustrated catalogue of marlins, sailfishes, spearfishes and swordfishes known to date. FAO Fisheries Synopsis, 125: 1 - 65.
3. FishBase (September, 2009)
   http://www.fishbase.org/Summary/SpeciesSummary.php?id=77
4. Burton, M. and Burton, R. (2002) International Wildlife Encyclopedia. Marshall Cavendish, New York.
5. Australian Museum (September, 2009)
   http://australianmuseum.net.au/Indo-Pacific-Sailfish-Istiophorus-platypterus
6. The Billfish Foundation (September, 2009)
   http://www.billfish.org/new/billfish.asp?page=Responsible Angling