arapaima

 

(ăr'əpī'mə) , tropical fish, Arapaima gigas, of the Amazon basin. It is perhaps the largest of the strictly freshwater fishes, reportedly reaching a length of 15 ft (4.5 m), but averaging 7 to 8 ft (2–2.4 m) in length and 200 lb (90 kg) in weight. The dorsal and anal fins of the arapaima are placed so far back that they appear to be part of the tail fin, giving a massive appearance to the posterior region. The scales are olive-green, turning increasingly reddish in the tail region and becoming crimson near the tail fin. The swim bladder, as in all members of the order Clupeiformes, is open to the pharynx; in the arapaima it is rich in blood vessels and serves as a lung. The arapaima uses its fins to hollow out a nest in clear, shallow, sandy-bottomed areas. It is a graceful swimmer despite its bulk, and it is valued as an aquarium fish as well as for food. It is classified in the phylum Chordata, subphylum Vertebrata, class Osteichthyes, order Clupeiformes, family Osteoglossidae.

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Arapaima
Conservation status
Data deficient (IUCN)
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Actinopterygii Order: Osteoglossiformes Family: Osteoglossidae Subfamily: Heterotidinae Genus: Arapaima Species: A. gigas
Binomial name
Arapaima gigas (Cuvier, 1829)

The arapaima, pirarucu, or paiche (Arapaima gigas) is a South American tropical freshwater fish. It is one of the largest freshwater fish in the world, reportedly with a maximum length in excess of 3 m (9.8 ft.) and weight up to 200 kg (440 lb.). As one of the most sought after food fish species in South America, it is often captured primarily by handheld nets for export, by spearfishing for local consumption, and, consequently, large arapaima of more than 2 m are seldom found in the wild today.

The diet of the arapaima consists of fish or even other kinds of small animals, including birds. The fish also has the ability to breathe air from the surface due to a lung-like lining of its throat, an advantage in oxygen-deprived water that is often found in the Amazon River. This fish is therefore able to survive extensive drought periods by gulping air and burrowing in the mud or sand of the swamps.

The arapaima has also been introduced for fishing in Thailand and Malaysia. It is also considered an aquarium fish, although it obviously requires a large tank and ample resources.

Fossils of arapaima or a very similar species have been found in the Miocene Villavieja Formation of Colombia. [1]

The tongue of this fish is thought to have medicinal qualities in South America. It is dried and combined with guarana bark, which is grated and mixed into water. Doses of this are given to kill intestinal worms.

Reproduction

Due to the geographic range that arapaima inhabits, the animal's life cycle is greatly affected by the seasonal flooding that occurs. Half of the year the arapaima experiences an abundance of water, which is a benefit to these aquatic organisms; however, the other half of the year the arapaima experiences drought conditions. The arapaima has adapted to this great fluctuation in many aspects of its life, including reproduction. The arapaima lays its eggs during the months of February, March, and April when the water levels are low. They build a nest approximately 50 cm wide and 15 cm deep, usually in sandy bottomed areas. As the water rises the eggs hatch and the offspring have the flood season to prosper, during the months of May to August. Therefore, the yearly spawning is regulated seasonally. The arapaima is a mouthbrooder.

Economic Importance for Humans

The arapaima is hunted and utilized in many ways by local human populations. Arapaima are harpooned or caught in large nets and the meat is said to be delicious. Since the arapaima needs to swim up to breathe air, traditional arapaima fishers often catch them by first clubbing them and then harpooning them dead. One individual can yield as much as 70 kg of meat. In addition, the arapaima's bony tongue is often used to scrape cylinders of dried guarana, an ingredient in some beverages, and the bony scales are used as nail files. This animal also appears in the pet trade, although to keep an arapaima correctly requires a large tank and can prove quite difficult.

Trivia

• In the Nintendo GameCube videogame Animal Crossing and subsequent sequels, the arapaima is the third rarest catch.

References

• World Conservation Monitoring Centre (1996). Arapaima gigas. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 06 May 2006.
• "Arapaima gigas". FishBase. Ed. Ranier Froese and Daniel Pauly. 10 2005 version. N.p.: FishBase, 2005.

(Lowe-McConnell 1987; Smith 1981, Luna and Froese, 2002)

• Gourmet Magazine (May 2007 Volume LXVII No. 5) Article: "The Quarter Ton Fish" pg. 106; Condé Nast Publications

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