| Salminus brasiliensis | |
|---|---|
emBonito.jpg) | |
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Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Characiformes |
| Family: | Bryconidae |
| Genus: | Salminus |
| Species: | S. brasiliensis |
| Binomial name | |
| Salminus brasiliensis | |
| Synonyms[2] | |
| |
Salminus brasiliensis, also known as the golden dorado,dorado,river tiger, dourado, orjaw characin, is a large, predatorycharaciformfreshwater fish found in central and east-centralSouth America.[3] Despite havingSalminus in its name, the dorado is not related to any species ofsalmon,[4] nor to the saltwater fish also called "dorado". It is very popular amongrecreational anglers and supports largecommercial fisheries.[5]
Dorado, both in the name of the fish and other uses such as theEl Dorado legend, originates from theLatin word for "gold",auratus (later modified intodauratus inVulgar Latin, and subsequentlyoro inItalian andSpanish, andouro inPortuguese).
The Portuguese worddourado and Spanishdorado both mean "golden"; this is applied to the fish due to its color displaying golden reflections.
The golden dorado has a large head, with powerful jaws filled with sharp teeth.[4] Adults are yellow-golden in color, but juveniles are more silvery.[6] Immatures (to a lesser extent adults) resembleBrycon hilarii andSalminus hilarii.[6][7] It reaches maturity around 37 cm (15 in) long.[citation needed] The average size of the golden dorado is about 3–10 kg (6.6–22.0 lb). The largest recorded size is 1.3 m (51 in) in length and 34 kg (75 lb) in weight.[8] Females grow considerably larger than males, but otherwise the sexes are similar.[6] It is the largestscaled freshwater fish in theRío de la Plata Basin (the only fish that can surpass it in size are certainriver stingrays andcatfish; both scaleless).[6]
The golden dorado is native to warm freshwater habitats in southernBrazil,Paraguay,Uruguay,Bolivia and northernArgentina. Here it inhabits theParaguay (including thePantanal),Paraná,Uruguay,Chapare,Mamoré andGuaporé River basins, and the drainage of theLagoa dos Patos.[3][9] Outside its native range, the golden dorado has beenintroduced to several southeast Brazilian river basins, notablyDoce,Paraíba do Sul,Iguazu andGuaraguaçu.[10]
Other South American river basins hold relatives of this species:S. franciscanus in theSão Francisco Basin,S. hilarii in the upperParaná,Amazon andOrinoco basins, andS. affinis in theSantiago andMagdalena basins inEcuador andColombia.[11]
The golden dorado generally prefers water temperatures between 20 and 28 °C (68–82 °F).[4] It ismigratory in response to temperature, season and food sources, and moves upstream, typically about 400 km (250 mi), tospawn in the spring and summer.[6] It is generally a solitary species, but migrates in groups.[6] The females reach maturity when 4–5 years old and can lay up to 2 million eggs,[6] which are released near the water surface.[4] Golden dorados can reach an age of more than 15 years.[6]
The golden dorado is theapex predator in its freshwater habitat.[7] They are primarilypiscivores, eating a wide variety of fish, but have also been recorded feeding on large insects,crustaceans and small vertebrates (for example, rodents, lizards and birds).[3][6] One of the adult dorado's favorite prey is thestreaked prochilod (Prochilodus lineatus), a species ofschooling fish that also is migratory.[4]
In the larval stage, golden dorados feed onplankton.[4] As they grow larger, they switch to insects and small fish.[4] At up to 30 cm (12 in) long, juveniles areaggressive mimics ofBrycon hilarii in both general shape and color, often staying near schools of thisfrugivorous species to be able to surprise smaller prey fish such asAstyanax andMoenkhausia tetras.[7] In contrast, adult dorados have been known to eatBrycon hilarii.[7]
The golden dorado has declined because ofoverfishing anddams, which restrict its breeding migration.[6] It is listed as a threatened species inRio Grande do Sul in Brazil[6] and in Paraguay; in the latter country, a five-year fishing ban was put into effect.[12]
In contrast, the golden dorado has been introduced for fishing to several rivers outside its native range.[10] Being a large highly predatory species, this represents a serious threat to the native fish in these rivers.[10]
