Arapaima
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Arapaima in the aquarium of the Cologne Zoo . |
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| Müller , 1843 |
Arapaima ( synonyms : Sudis Cuvier 1816; Vastres 1847 Valenciennes,), South America Pirarucu or paiche called, is a freshwater fish species from the order of Knochenzünglerartigen (Osteoglossiformes). Arapaima means "red fish" in the Tupí-Guaraní languages . Arapaimas are among the largest freshwater fish in the world. They can be over two meters long and weigh over 130 kg.
distribution
Arapaimas come between 5 ° north and 11 ° south latitude in northern South America in the Amazon and the lower reaches of its southern tributaries Rio Madeira , Rio Tapajós and Rio Xingu , in the larger watercourses of the island of Marajó in the mouth of the Amazon, in the tributaries of the Amazon upper reaches Pastaza , Rio Pacaya and Río Ucayali , in the Rio Araguaia and in the lower reaches of the Rio Tocantins as well as in the Capim south of the island of Marajó. In the rivers coming from the south, it only lives in the lowland sections, not above the rapids that these rivers form when they flow from the sierra into the actual Amazon basin . In the northern Amazon tributary Rio Negro there are no fish because they cannot find enough food in its nutrient-poor black water . In contrast, they occur in its tributaries Rio Branco , Río Jufari and in the lower reaches of the Río Demin . The Rio Branco leads white water . In Guyana, arapaimas live in the Essequibo . The preferred temperature of the arapaimas is 25 ° C to 29 ° C, the preferred pH value 6.0 to 6.5.
features
Arapaima can be over 2 meters long. The largest known specimen was 2.32 m long and weighed 133 kg. But it usually remains at a length of up to two meters. An often quoted statement by Robert Hermann Schomburgk from 1836 of 4.5 m (15 feet) long and about 186 kg (410 pounds ) is unbelievable, since such large arapaimas would have to be much heavier. Because of this unreliable hearsay-only size specification, Arapaima gigas has often been referred to as the largest freshwater fish in the world. In terms of length, however, it is in the order of magnitude of the European catfish and well below Urogymnus polylepis , a stingray that occurs in the river basins of the Mekong and Mae Nam Chao Phraya ( Chao Phraya River ). Schomburgk handed down a length of 2.46 m (8 feet and 1 inch) for a specimen he measured.
The body of the arapaimas is elongated and round in cross section. It is olive green and has a lot of silvery sheen. On the large scales there are crescent-shaped rust-colored or orange-red spots. The iris is yellow or red. In the side line row (SL) there are 35 or 36 scales, in a line perpendicular to the longitudinal axis 3 to 3.5 scales on each side of the body. The dorsal fin is supported by 20 to 24, the longer anal fin by 26 to 40 fin rays.
The fish have a mouth above them with which they can ingest atmospheric air. To do this, they rise to the surface and take in the air with a loud, striking gulp. The arapaima's swim bladder has a lung-like tissue that can remove oxygen from the air. This additional breathing organ is considered to be the adaptation of the arapaimas to the often oxygen-poor water of the floodplains in the Amazon basin. This enables them to go without water for up to 24 hours.
Reproduction
Arapaimas spawn in April and May. To do this, the fish build a nest half a meter in diameter and 15 cm high on sandy bottoms. Eggs and young fish are guarded.
nutrition
Adult animals that are one year old or older feed mainly on other fish. In addition, invertebrates , amphibians , water fowl and smaller mammals are among their prey. Young animals that are cared for by their parents for up to three months also eat insects , fish larvae and other small organisms.
Systematics
The genus Arapaima was in 1843 by the German physician and naturalist John Mueller described . The type of the genus is Sudis gigas Schinz 1822 (= Arapaima gigas ). Three other species, which were described in 1847 by the French zoologist Achille Valenciennes , were synonymous with Arapaima gigas in 1868 by Müller in a short document without detailed analysis, with which Arapaima became monotypical . This was true for the following 145 years, until the American ichthyologist Donald J. Stewart re-analyzed initial descriptions and type specimens (if available) in 2013 and revalidated the species, and described a new species with Arapaima leptosoma .
Arapaima belongs to the family of the Arapaimidae , to which only the African bone-wolf ( Heterotis niloticus ) belongs. The American ichthyologist Joseph S. Nelson assigns the family under the name Heterotidinae as a subfamily to the osteoglossids (Osteoglossidae).
species
- Arapaima agassizii (Valenciennes, 1847)
- Arapaima gigas (Schinz, 1822)
- Arapaima leptosoma Stewart, 2013
- Arapaima mapae (Valenciennes, 1847)
Danger
Arapaimas are at risk from overfishing . However, the IUCN cannot specify any hazard levels because insufficient data are available. In Bolivia, where the Apaimas gigas were introduced from Peru around 1976, they are considered an invasive species , which may have been responsible for the sharp decline in native fish species in some river sections that has been observed since then and which could endanger their stocks in the long term. In 2017, the Bolivian government and several research organizations published a comprehensive study on the ecological and socio-economic effects of the species in Bolivia.
literature
- Karl-Heinz Lüling: The bone-wolf fish. The new Brehm library, A. Ziemsen Verlag, Wittenberg, 1977
- Karl-Heinz Lüling: On the biology and ecology of Arapaima gigas (Pisces, Osteoglossidae) ; Zoomorphology Journal Vol. 54, No. 4, pp. 436-530; 1964 Springer Verlag
- Donald J. Stewart 2013: Re-description of Arapaima agassizii (Valenciennes), a Rare Fish from Brazil (Osteoglossomorpha: Osteoglossidae). Copeia . 2013 (1): 38-51. doi: 10.1643 / CI-12-013
- Donald J. Stewart 2013: A New Species of Arapaima (Osteoglossomorpha: Osteoglossidae) from the Solimões River, Amazonas State, Brazil. Copeia . 2013 (3): 470-476. doi: 10.1643 / CI-12-017
Web links
- Arapaima on Fishbase.org (English)
- Arapaima (Arapaima gigas) in the WWF species lexicon
Individual evidence
- ^ Robert Hermann Schomburgk: The natural history of fishes of Guiana. Part I, page 201. In: The Naturalists' Library, Volume 3 . W. Jardine (ed.). WH Lizars, Edinburgh, Scotland. 1841
- ↑ a b Archived copy ( memento of the original dated November 3, 2012 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ http://www.zoo-leipzig.de/unsere-tiere/tier-details/tier/arapaima-1/
- ^ J. Müller, 1843: Contributions to the knowledge of the natural families of fish. Archive for Natural History v. 9: 292-330.
- ↑ La aventura de la Paiche en la Amazonia de Bolivia , laregion.bo . Retrieved March 2, 2020.
- ↑ Can We Really Eat Invasive Species into Submission , Scientific American . Retrieved March 2, 2020.
- ↑ Bases técnicas para el manejo y aprovechamiento del paiche (Arapaima gigas) en la cuenca amazónica boliviana , faunagua.org . Retrieved March 2, 2020.
