Identificação e variação genética de Colossoma macropomum e seus híbridos, nativos e de cativeiros da região oeste do Pará.

Abstract

In northern Brazil aquaculture has shown a steady growth in recent years. This growth has been attributed mainly to the cultivation of Colossoma macropomum and hybrids produced from this species with Piaractus mesopotamicus and Piaractus brachypomus. Despite the cultivation of these organisms is critically important to provide alternative sources to the exploitation of fishing resources, it needs to be strategically planned and monitored in order to be profitable and do not bring risks to wild populations of related species, or damage to human populations. Hybrids of Tambaqui are quite similar to the parental species and the cultivation of these individuals may be especially problematic. Cultivated individuals may be genetically distinct from wild populations or have low genetic diversity, representing a risk for native and captivity specimens. In this study, using the Control Region of mitochondrial DNA and PCR Multiplex gene α - Tropomyosin on native and captive individuals of the Western Region of Para, identification errors were recorded in 75% of analyzed fish farms, with the cultivation simultaneous hybrids with parental species, and 22% of errors in fish farms believed to exist only pure species. We also found high genetic diversity in both native populations and medium levels of diversity in captive individuals of Colossoma macropomum, with a slight divergence among native and captive populations. These results highlight the problem of growing hybrids in the Amazon, specially if they are simultaneouslyculturedtogether with native specimens, and warns of possible commercialization of hybrid as pure species or vice versa. The results regarding the genetic diversity of populations cultured Colossoma macropomum contrast to studies conducted in other regions of the state of Para and other states of Brazil that pointed to historical inbreeding in a matrix-producing fingerlings, and reveal a new model of production.