The arapaima, pirarucu, or paiche is any large species of bonytongue in the genus Arapaima native to the Amazon Basin and Essequibo River basins of South America. Arapaima is the type genus of the subfamily Arapaiminae within the family Osteoglossidae.[Castello, L.; and Stewart, D.J (2008). Assessing CITES non-detriment findings procedures for Arapaima in Brazil. NDF Workshop case studies (Mexico 2008), WG 8 – Fishes, Case study 1] They are among the world's largest freshwater fish, reaching as much as in length.[ They are an important food fish. They have declined in the native range due to overfishing and habitat loss. In contrast, arapaima have been introduced to several tropical regions outside the native range (within South America and elsewhere), where they are sometimes considered invasive species.][Miranda-Chumacero, G.; Wallace, R.; Calderón, H.; Calderón, G.; Willink, P.; Guerrero, M.; Siles, T.M.; Lara, K.; and Chuqui, D. (2012). Distribution of arapaima (Arapaima gigas) (Pisces: Arapaimatidae) in Bolivia: implications in the control and management of a non-native population. BioInvasions Records 1(2): 129–138] In Kerala, India, arapaima escaped from aquaculture ponds after floods in 2018.[ ResearchGate. CABD 20210033477.] Its Portuguese name, pirarucu, derives from the Tupi language words pira and urucum, meaning "red fish".
Arapaima was not traditionally regarded as a monotypic genus, but later, several species were distinguished.[Stewart, D.J. (2013). A New Species of Arapaima (Osteoglossomorpha: Osteoglossidae) from the Solimões River, Amazonas State, Brazil. Copeia, 2013 (3): 470–476.][Stewart, D. J. (2013). Redescription of Arapaima agassizii (Valenciennes), a rare fish from Brazil (Osteoglossomorpha, Osteoglossidae). Copeia, 2013: 38–51] As a consequence of this taxonomic confusion, most earlier studies were done using the name A. gigas, but this species is only known from old museum specimens and the exact native range is unclear. The regularly seen and studied species is A. arapaima,[Dawes, J: Arapaima Re-classification and the Trade. Retrieved 24 May 2014] although a small number of A. leptosoma also have been recorded in the aquarium trade.[Howard, B.C. (13 October 2013). New Species of Giant Air-Breathing Fish: Freshwater Species of the Week. National Geographic. Retrieved 24 May 2014] The remaining species are virtually unknown: A. agassizii from old detailed drawings (the type specimen itself was lost during World War II bombings) and A. mapae from the type specimen.[
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Taxonomy
FishBase recognizes four species in the genus.[Clarke, M. (15 January 2010). Two Arapaima species, not one. Practicalfishkeeping. Retrieved 24 May 2014.]
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Arapaima agassizii (Valenciennes, 1847) (Agassiz's arapaima)
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Arapaima gigas (Schinz, 1822) ( pirarucu, arapaima)
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Arapaima leptosoma D. J. Stewart, 2013 (slender arapaima; Solimoes arapaima)
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Arapaima mapae (Valenciennes, 1847) (Mapa arapaima)
These fish are widely dispersed and do not migrate, which leads scientists to suppose that more species are waiting to be discovered in the depths of the Amazon Basin harbors. Sites such as these offer the likelihood of diversity.
Morphology
Arapaima can reach lengths more than , in some exceptional cases even exceeding and over . The maximum recorded weight for the species is , while the longest recorded length verified was 3.07 m (10 ft 1 in). Anecdotal reports suggest that specimens as long as 4.57 m (15 ft 0 in) exist, but verification is deemed impossible, and thus considered questionable. As a result of overfishing, arapaima more than are seldom found in the wild.
The arapaima is torpedo-shaped, with large, blackish-green scales and red markings. It is streamlined and sleek, with its dorsal fin and set near its tail.
Arapaima scales have a mineralised, hard, outer layer with a corrugated surface under which lie several layers of collagen fibres in a Bouligand-type arrangement.
Ecology
The diet of the arapaima consists of fish, , fruits, seeds, insects, and small land animals that walk near the shore.
Arapaima may leap out of the water if they feel constrained by their environment or harassed.
Life history/behavior
Reproduction
Due to its geographic ranges, arapaima's lifecycle is greatly affected by seasonal . Various pictures show slightly different coloring owing to colour changes when they reproduce.["Fish Warrior: Amazon Giant." http://natgeotv.com/. National Geographic. Web.
<[8]>.] The arapaima lays its eggs when water levels are low or beginning to rise. They build a nest about wide and deep, usually in muddy-bottomed areas. As the water rises, the eggs hatch and the offspring have the flood season from May to August in which to prosper, such that yearly spawning is regulated seasonally.
Breeding
The arapaima male is a mouthbrooder, like the related Osteoglossum genus, meaning the young are protected in his mouth until they are older. The female arapaima helps to protect the male and the young by circling them and fending off potential predators.
In his book, Three Singles to Adventure, naturalist Gerald Durrell reported that in British Guyana, female arapaima had been seen secreting a white substance from a gland in the head, and that their young were seemingly feeding on the substance.
Evolution
Some 23-million-year-old fossils of arapaima or a very similar species have been found in the Miocene Villavieja Formation of Colombia.
Relation to humans
is exploited in many ways by local human populations.
Its tongue 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 are given to kill intestinal worms.
The bony tongue is used to scrape cylinders of dried guarana, an ingredient in some beverages, and the bony scales are used as nail files.
Arapaima produce boneless steaks and are considered a delicacy. In the Amazon region, locals often salt and dry the meat, rolling it into a cigar-style package that is then tied and can be stored without rotting, which is important in a region with little refrigeration. Arapaima are referred to as the "cod of the Amazon", and can be prepared in the same way as traditional salted cod.
Designers have begun using the skin of the arapaima as leather to make jackets, shoes, and handbags, and to cover furniture.
In July 2009, villagers around Kenyir Lake in Terengganu, Malaysia, reported sighting A. gigas. The "Kenyir monster", or "dragon fish" as the locals call it, was claimed to be responsible for the mysterious drowning of two men on 17June.
In August 2018, India Times reported that arapaima has been spotted in the Chalakudy River, following floods in Kerala;
The arapaima is depicted on both the flag and the seal of the Department of Ucayali, Peru.
Fishing
Wild arapaima are or caught in large nets. Since the arapaima needs to surface to breathe air, traditional arapaima fishermen harpoon them and then club them to death. An individual fish can yield as much as of meat.
The arapaima was introduced for fishing in Thailand and Malaysia. Fishing in Thailand can be done in several lakes, where specimens over are often landed and then released.
On 14 May 2020, a 30 kg specimen was found floating in the river in Angkor Wat area, Krovanh village, Sangkat Norkor Thom, Siem Reap, Cambodia; the locals said it was a rare fish, and not commonly seen in this area.
With catch-and-release after the fish is landed, it must be held for 5 minutes until it takes a breath. The fish has a large blood vessel running down its spine, so lifting the fish clear of the water for trophy shots can rupture this vessel, causing death.
Aquaculture
In 2013, Whole Foods began selling Aquaculture arapaima in the United States as a cheaper alternative to halibut or Chilean sea bass.
In Thailand, the only legal breeding farm is located in Tambon Phrong Maduea, Amphoe Mueang Nakhon Pathom, Nakhon Pathom Province. This has been approved by both the Department of Fisheries and CITES since early 2018, and has been exporting them worldwide as an aquarium fish.
Conservation
Arapaima are particularly vulnerable to overfishing because of their size and because they must surface periodically to breathe. Some 7000 tons per year were taken from 1918 to 1924, the height of commercial arapaima fishing; demand led to farming of the fish by native ribeirinhos.[ River Monsters episode name: "Unhooked", Animal Planet, 16 July 2010 10AM PDT.] As efforts at restricting catches were largely unsuccessful, arapaima fishing was banned outright in Brazil in 1996, due to declining populations. Indeed, a 2014 study found that the fish were depleted or overexploited at 93% of the sites examined and well-managed or unfished in only 7%; the fish appeared to be Local extinction in 19% of these sites.
Colombia only bans fishing and consumption of the arapaima between October 1 and March 15, during breeding season.
==Gallery==
Further reading
