Genetic diversity of Salminus brasiliensis wild populations in downstream and upstream Cachoeira Branca, Verde River MS Brazil: a preliminary view

Abstract

Although hydroelectric power plants generate most electricity in Brazil, the dams provide environmental barriers which also include the interruption of fish migration. Current study, conducted prior to the construction of São Domingos HPP on the shaft of the Cachoeira Branca (waterfall) on the Verde river, state of Mato Grosso do Sul, Brazil, evaluated the genetic diversity of two natural populations of dourado (Salminus brasiliensis) located downstream (Population A -PopA) and upstream (Population B -PopB) the waterfall. Eight primers were employed to analyze 56 specimens (PopA: 26; PopB: 30) and observed in 102 fragments, of which 86 were polymorphic (84.3%). Low frequency fragments (PopA: 2; PopB: 1), three limiting fragments (PopA) and three exclusive fragments (PopB) were identified. The intra-population genetic variability calculated the Shannon index, whilst the percentage of polymorphic fragments showed high rate variability within each population (PopA: 0.300 and 60.80% and PopB: 0.411 and 79.40%, respectively). The distance and genetic identity revealed high genetic differentiation (0.076 and 0.927, respectively). Results reveal that populations have high intra-population genetic variability and genetic differentiation between them, with low gene flow. ResumoAs usinas hidrelétricas são responsáveis por gerar a maioria da energia elétrica utilizada no Brasil, entretanto, suas construções podem gerar entraves ambientais, entre eles a interrupção da migração de peixes. O presente estudo foi realizado no período anterior a construção da Usina Hidroelétrica (UHE) São Domingos sobre o eixo da cachoeira Branca, no rio Verde -Mato Grosso do Sul (Brazil), e teve como objetivo avaliar a diversidade genética de duas populações naturais de dourado (Salminus brasiliensis) localizadas à jusante (População A -PopA) e montante (População B -PopB) da cachoeira. Foram utilizados oito iniciadores para analisar 56 indivíduos (PopA: 26; PopB: 30). Observaram-se um total de 102 fragmentos, dos quais 86 foram polimórficos (84,3%). Foram identificados fragmentos de baixa frequência (PopA: 2; PopB: 1), três fragmentos limitantes (PopA) e três fragmentos exclusivos (PopB). A variabilidade genética intra-populacional calculada com o índice de Shannon e pela porcentagem de fragmentos polimórficos mostrou altos valores de variabilidade dentro de cada população (PopA: 0,300 e 60,80% e PopB: 0,411 e 79,40%, respectivamente). A distância e identidade genética mostraram uma alta diferenciação genética (0,076 e 0,927, respectivamente). Conclui-se que as populações apresentaram alta variabilidade genética intra-populacional e diferenciação genética entre si, com baixo fluxo gênico.

Basin‐scale distribution and haplotype partitioning in different genetic lineages of the Neotropical migratory fish Salminus brasiliensis

“…Indeed, four different genetic lineages of S. hilarii are known in South America (Machado et al, ). Similarly, Ribeiro et al () also pointed out a strong pattern of genetic differentiation between populations of S. brasiliensis downstream and upstream of a natural barrier. The effects of artificial barriers on genetic structure of fish populations in the Neotropical region have been reported for migratory species other than Salminus (Garcez, Calcagnotto, & Almeida‐Toledo, ; Sekine, Prioli, Prioli, & Júlio, ).…”

Genetic diversity of Piracanjuba populations in fish stocking programs in the Tietê River, Brazil

“…The use of molecular markers to assess the genetic composition of fish populations is an important strategy for measuring the genetic variability among specimens. Recent studies have shown that the use of RAPD (Random Amplified Polymorphic DNA) and microsatellites may provide important information on population genetics in fish culture stations and in natural environments, and these markers are widely used for analysis of genetic variability in several species (Ashikaga et al, 2015;Ribeiro et al, 2016;Coimbra et al, 2017;Souza et al, 2018).…”

Genetic diversity of migratory fish populations of the Rio Grande Reservoir (São Paulo, Brazil)

“…Previous studies have shown that the fragmentation of rivers by the presence of dams may have negative effects on the genetic structure of Brazilian migratory fish populations (RAMOS et al, 2012;ASHIKAGA et al, 2015;RIBEIRO et al, 2016). However, notably, this is not the only factor that endangers the populations of these fishes, as they may also be affected by overfishing, pollution, river banks deforestation, and habitat destruction, among others (LOPERA-BARRERO et al, 2015).…”