Hoplias aimara
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| ( Valenciennes , 1847) |
Hoplias aimara ( synonym : Hoplias macrophthalmus ), also Anjumara, Anjoemara, Guabina, Fasaco, in Portuguese Trairão or English Wolf Fish belongs to the predatory tetrafamily(Erythrynidae) and is one of the large predatory fish in South America .
distribution
Hoplias aimara is found mainly in the rivers of the tropical rainforest in the northern part of South America. The species is found in Brazil ( Amapá state , in the Rio Tocantins , Rio Xingu , Rio Tapajós and Rio Trombetas), Colombia , Venezuela , Guyana , French Guiana and Suriname . The largest specimens of H. aimara are found in the Coppename River in Suriname.
description
Hoplias aimara is the largest species of the genus Hoplias with a body length of 120 centimeters and weights of 40 kilograms . H. aimara has an elongated cylindrical shape. Along the sideline , they have 32 to 47 scales. The pectoral fin has nine to 14 fin rays, the anal fin ten to 12 and the dorsal fin eight to 15. Their caudal fin has a rounded shape. They have pointed and very sharp fangs on their palatal bone . On the side of the gill cover they have a characteristic black spot. The back is usually dark or light brown to golden brown in color, lighter on the sides, offset with dark vertical stripes. Its drawing can vary according to the geographical region of origin. With its characteristic pattern, H. aimara adapts to the stone bed of the rivers.
Way of life
The species occurs in waters with a pH value between 6.5 and 8 and water temperatures between 23 ° C and 30 ° C. Its habitats include swampy bank regions as well as clear water or black water rivers in the tropical rainforests. Hoplias aimara can also be found behind waterfalls, rapids or in the countercurrent of rivers and streams. There he lies in ambush for prey fish. Because of its hunting behavior, it is also known as a wolffish. While young fish still prey in small schools, larger specimens develop into solitary animals. He shows an opportunistic way of eating, for example by eating small animals and insects that fall into the water. Hoplias aimara is mostly active at dusk and at night. Its spawning season begins with the rainy season, which lasts from December to March. Depending on the body size, a Rogner can produce between 6,000 and 60,000 eggs. They take care of the brood and defend the clutch against spawning predators. In aquariums the species often shows very aggressive and cannibalistic behavior.
Taxonomy
Scientists have long believed that there were two species of Giant Trahiras: Hoplias aimara ( Valenciennes , 1846) and Hoplias macrophthalmus ( Pellegrin , 1907). Both were first described in French Guiana . Probable catches of Hoplias aimara in the Orinoco and Rio Purus were misidentifications. Later morphometric studies showed that the holotype relates to Hoplias aimara and Hoplias macrophthalmus and belongs to a taxon . According to the International Rules for Zoological Nomenclature , the name Hoplias aimara takes precedence.
Economical meaning
Because of its tasty meat, it is a popular food fish. For the Waiwai Indians in Guiana it is one of the staple foods. Its occurrence has decreased in some regions due to overfishing.
Hoplias aimara and man
Attacks by Hoplias aimara on people have been reported. An eyewitness claims that one of these fish jumped out of the water and snapped at his foot while crossing the river on an overturned log.
Hazardous situation
Studies on the biomagnification of mercury have shown that Hoplias aimara, as a predator, stores large amounts of harmful substances in its meat. They are also impaired by the increasing nitrogen input into the waters. After water engineering measures, Hoplias aimara's radius of action is limited . After the construction of the Petit-Saut Dam in French Guiana, the fish are more faithful to their location than in an unspoilt body of water with floodplain forests during the rainy season.
Individual evidence
- ↑ a b c d e f Hoplias aimara on Fishbase.org (English)
- ↑ Archive link ( Memento of the original from September 30, 2013 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.
- ↑ George MT Mattox, Mônica Toledo-Piza, Osvaldo T. Oyakawa and JW Armbruster: Taxonomic Study of Hoplias Aimara (Valenciennes, 1846) and Hoplias macrophthalmus (Pellegrin, 1907) (Ostariophysi, Characiformes, Erythrinidae) In: Copeia , September 2006, September 2006, No. 3, pp. 516-528
- ↑ http://www.conservation.org/where/south_america/guyana/Pages/fishes.aspx
- ↑ Documentation River Monster , Volume 21
- ↑ G. Durrieu, R. Maury-Brachet, A. Boudou: Goldmining and mercury contamination of the piscivorous fish Hoplias aimara in French Guiana (Amazon basin). In: Ecotoxicology and environmental safety. Volume 60, Number 3, March 2005, pp. 315-323, doi : 10.1016 / j.ecoenv.2004.05.004 , PMID 15590010 .
- ↑ G. Moraes and VLP Polez: Ureotelism is inducible in the neotropical freshwater Hoplias malabaricus (Teleostei, Erythrinidae) In: Brazilian Journal of Biology , Vol. 64 No. 2, São Carlos May 2004 Online
- ^ L. Tito de Morais and J. Rafrray: Movements of Hoplias aiming the filling phase of the Petit-Saut dam, French Guyana. In: Journal of Fish Biology (1999) 54, pp. 627-635 online
- ^ L. Tito de Morais and J. Rafrray: Behavior of Hoplias aimara during the filling phase of the Petit-Saud Dam (Sinnamary River, French Guayana South America). In: E. Baras and JC Philippart: Underwater Biotelemetry, Proceedings of the First Conference and Workshop on Fish Telemetry in Europe. University of Liege, Belgium, pp. 153-160
