The dorado , damita or pirayú ( Salminus brasiliensis or Salminus maxillosus ) is a Poisson about the Characiformes, of big size which lives tropical and subtropical water certain zones of the South America, in the basins of the rivers río Paraná, Río Paraguay, Uruguay, like in the rivers Chapare and Mamoré of the basin of the the Amazon in Bolivia.

It is one of the principal objects of sporting fishing in Argentine, with the various species of surubí ( Pseudoplatystoma ).

Description

Adult, it exceeds the meter length and reached 25 kg of weight. He has a strong musculature related to his habitat, the rapids river of the area, which makes its capture difficult.

Salminus brasiliensis is a fish of body salmonoide, robust, moderately compressed laterally. The recorded specimens of very big size reached 110 and even 116 cm. The head is large, until the quarter overall length, of conical form. The mouth reaches half of the head. It is decorated strong conical teeth.

Practices - Food

Salminus brasiliensis is a voracious predator. It is called tiger LED río . He lives the high tension currents which are formed in the stony funds or the mouths of the affluents, where his higher musculature enables him to operate with more facility than his preys, in general of other fish, and to attack when those are disarmed in the current.

He migrates regularly to the length of the rivers of his field, continuing his favorite preys, especially the sábalo ( Prochilodus lineatus ). The other species which it captures are the boga ( Leporinus obtusidens ), the bagre (of the kind Pimelodus and the Parapimelodus valenciennesi , catfishes of the family of the Pimelodidae ) and the piraña or palometa ( Serrasalmus marginatus ), as well as shellfish of the kind Macrobrachium .

Reproduction

For the reproduction, they go up the current during a migration known under the name of piracema , during the months of southern spring (October and November). Several males court and follow the same female. At the time of this ritual of approach the individuals jump out of water, and it is then easy to locate them and to observe them. Fecundation is external, the female laying until 200.000 eggs in only once. They do not supervise eggs, deposited in running water places. After a one day incubation the alevins hatch; they are more or less 5 mm length. Sexual maturity is reached the second year at the males and the third in the females.

The immature specimens then feed from protist S and from crustacean S and insect S.

The salminus brasiliensis can reach fourteen years of age.

Conservation

In Argentina

In 2005 the law Nº 26.021 of the Congreso of Nación Argentina declared the dorado fish of national interest . The law ratified an initiative of the Secretariat in the Ambient conditions, which sought to reinforce the conservation of the species, threatened by fishing commercial and the construction of stoppings which stop the migratory flux.

The declared fishing of dorado reached the 200 annual tons during the years 1980, provocant a significant decrease in the populations. The recovery of manpower of those runs up against the obstacles set up on their reproductive migration, especially the Barrage of Yacyretá. During the construction of this last one had envisaged four elevators to only facilitate the transit of fish upstream, but two of them were built, and one of those does not function. Impossibility of laying in adequate sites forces stocking with fish to occur downstream before the alevins are not prepared to face the conditions which reign there and which are imposed to them, which causes a mortality raised among them.

The projects of conservation include the reinforcement of the existing tank in the Étangs of Iberá, which industrially represent a good habitat for the sowing of youthful products in pisciculture. The principal danger in this zone for the immature specimens is the piraña palometa (Serrasalmus marginatus) , present in excess for lack of its natural predator, the caiman or yacaré ( caiman jacaré and caiman latirostris ), of which the number is affected by the poaching.

Synonyms

• Hydrocynus brasiliensis

• Hydrocyon brevidens
• Salminus cuvieri
• Salminus orbignyanus
• Salminus maxillosus
• Salmo auratus
• Salmo vigintiseptemradiatus

References

External bonds

• migrating Poisson of the basin of High Paraná in Brazil

• Fischbase Species