أراپايما arapaima أوpirarucu، أوpaiche is any large species of bonytongue in the genus Arapaima native to the Amazon and Essequibo basins of South America. Genus Arapaima is the type genus of the family Arapaimidae. They are among the world's largest freshwater fish, reaching as much as 3 م (9.8 قدم). 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. Its Brazilian Portuguese name, pirarucu, derives from the Tupi language words pira and urucum, meaning "red fish".

Arapaima was traditionally regarded as a monotypic genus, but later several species were distinguished. 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, although a small number of A. leptosoma also have been recorded in the aquarium trade. 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.A. arapaima is relatively thickset compared to the remaining species.

التبويب

FishBase recognizes four species in the genus. In addition to these, evidence suggests that a fifth species, A. arapaima, should be recognized (this being the widespread, well-known species, otherwise included in A. gigas).

• Arapaima arapaima Valenciennes 1847
• Arapaima agassizii Valenciennes 1847 (Agassiz's arapaima)
• Arapaima gigas Schinz 1822 (pirarucú, arapaima)
• Arapaima leptosoma D. J. Stewart, 2013 (Slender arapaima；Solimoes arapaima)
• 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 among the depths of the Amazon Basin harbors. Sites such as these offer the likelihood of diversity.

الشكل

Arapaima can reach lengths more than 2 م (6 قدم 7 بوصة), in some exceptional cases even more than 2.5 م (8 قدم 2 بوصة) and over 100 kغ (220 رطل). The maximum recorded weight for the species is 200 kغ (440 رطل), while the longest recorded length was 4.52 m (15 ft). As a result of overfishing, large arapaima more than 2 م (6 قدم 7 بوصة) 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 and anal fins 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. In a structure similar to plywood, the fibres in each successive layer are oriented at large angles to those in the previous layer, increasing toughness. The hard, corrugated surface of the outer layer, and the tough internal collagen layers work synergistically to contribute to their ability to flex and deform while providing strength and protection—a solution that allows the fish to remain mobile while heavily armored. The arapaima has a fundamental dependence on surface air to breathe. In addition to gills, it has a modified and enlarged swim bladder, composed of lung-like tissue, which enables it to extract oxygen from the air.

البيئة

The diet of the arapaima consists of fish, crustaceans, and small land animals that walk near the shore.^[] The fish is an air breather, using its labyrinth organ, which is rich in blood vessels and opens into the fish's mouth, an advantage in oxygen-deprived water that is often found in the Amazon River. This fish is able to survive in oxbow lakes with dissolved oxygen as low as 0.5 ppm. In the wetlands of the Araguaia, one of the most important refuges for this species, it is the top predator in such lakes during the low-water season, when the lakes are isolated from the rivers and oxygen levels drop, rendering its prey lethargic and vulnerable.

Arapaima may leap out of the water if they feel constrained by their environment or harassed.

دورة الحياة والسلوك

التكاثر

Due to its geographic ranges, arapaima's lifecycle is greatly affected by seasonal flooding. Various pictures show slightly different coloring owing to colour changes when they reproduce. The arapaima lays its eggs during the months when water levels are low or beginning to rise. They build a nest about 50 cم (1.6 قدم) wide and 15 cم (0.49 قدم) deep, usually in muddy-bottomed areas. As the water rises, the eggs hatch and the offspring have the flood season during May to August to prosper such that yearly spawning is regulated seasonally.

التهجين

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 Guiana, 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.

التطور

Fossils of arapaima or a very similar species have been found in the Miocene Villavieja Formation of Colombia Museum specimens are found in France, England, United States, Brazil, Guyana, Ecuador and Perú.

العلاقة بالبشر

Arapaima is used in many ways by local human populations.

It is considered an aquarium fish, one that requires substantial space and food.

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.^{[بحاجة لمصدر]} 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 17 June.

الصيد

Fishing for arapaima is allowed only in certain remote areas of the Amazon basin, and must either be catch-and-release or subsistence harvesting by native peoples.

Some 7000 tons per year were taken from 1918 to 1924, the height of its commercial fishing. Demand led to farming of the fish by the ribeirinhos (people living on riverbanks).

They are harpooned 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 70 kغ (2,500 أونصة) of meat.

The arapaima was introduced for fishing in Thailand and Malaysia. Fishing in Thailand can be done in several lakes, where specimens over 150 kغ (5,300 أونصة) are often landed and then released.

With catch-and-release after the fish is landed, it must be held forخمسة 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.

البئة المائية

In 2013, Whole Foods began selling farm-raised 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.

الوضع

الحفاظ

The status of the arapaima population in the Amazon River Basin is unknown, hence it is listed on the IUCN red list as data deficient. Conducting a population census in so large an area is difficult, as is monitoring catches in a trade that is largely illegal. Commercial arapaima fishing is banned by the Brazilian government due to its commercial extinction.^[]Colombia bans the fishing and consumption of the arapaima between October 1 and March 15 as it is within the seasons that the fish breed.

التهديدات

A 2014 study found that the fish was depleted or overexploited at 93% of the sites examined and well-managed or unfished in only 7%; the fish appeared to be extirpated in 19% of these sites. Arapaima are particularly vulnerable to overfishing because of their size and because they must surface periodically to breathe.

معرض صور

• Arapaima at the Shedd Aquarium

• Arapaima at the Manila Ocean Park

• Arapaima at the Cologne Zoological Garden

• Arapaima leptosoma at the zoo (sea aquarium) in Sevastopol

• Arapaima depicted on a 1954 postage stamp of British Guiana

المراجع

للاستزادة

• New Worlder "The Paiche Hunter"
• نطقب:FishBase
• Gourmet Magazine (May 2007 Volume LXVII No. 5) Article: "The Quarter Ton Fish" pg. 106; Condé Nast Publications
• National Geographic News "Search Is on for World's Biggest Freshwater Fish"

خطأ لوا في وحدة:Taxonbar على السطر 140: attempt to index field 'wikibase' (a nil value).