Genetic diversity in natural populations of Colossomamacropomum in the Brazilian Amazon region and in populations farmed in Northeast Brazil based on ISSR markers

The tambaqui (Colossoma macropomum) is a fish native to the Brazilian Amazon region and is an important species for the local aquaculture industry. In this study, genetic diversity of four tambaqui populations was assessed using inter-simple sequence repeat (ISSR) markers. We tested 140 specimens, 64 of which were collected from two fish farms located in the State of the Bahia from BAHIA PESCA S/A ((BA); 33 from Cachoeira-BA and 31 from Dias d’Avila-BA), 46 from the Departamento Nacional de Obras Contra Seca (DNOCS) in Pentecoste in the State of Ceara (CE), and 30 from a wild population in Jurua River in the State of Amazonas (AM). Thirteen markers were used to test genetic structure and diversity. A total of 184 amplifieds were produced, 157 of which were polymorphic. The ratios of polymorphic loci varied across the four populations, with lower polymorphism in the population from Cachoeira-BA (54.35%) and higher polymorphism in the population from the Jurua River (79.35%). The indices of heterozygosity (H) and Shannon (I) were similar among the farmed populations and were lower than those in the natural population. Lower values were observed in the population of Cachoeira-BA (H = 0.1726; I = 0.2606), and the highest values in the Jurua River populations (H = 0.2404; I = 0.3643). Analysis of molecular variance revealed the highest variation occurred within populations (61%) and the difference between populations was low (39%). We concluded that compared with the wild population, farmed populations had lower genetic diversity and that genetic information must be used in future management schemes to improve genetic population structure.