Pimentel Juliana da Silva Martins, Ludwig Sandra, Resende Leonardo Cardoso, Brandão-Dias Pedro Ferreira Pinto, Pereira Adriana Heloísa, de Abreu Nazaré Lúcio, Rosse Izinara Cruz, Martins Ana Paula Vimieiro, Facchin Susanne, Lopes João de Magalhães, Santos Gilmar Bastos, Alves Carlos Bernado Mascarenhas, Kalapothakis Evanguedes
Department of Genetic, Ecology and Evolution Institute of Biological Sciences Federal University of Minas Gerais Belo Horizonte Brazil.
Pitágoras College Belo Horizonte Brazil.
Ecol Evol. 2020 Sep 16;10(19):10314-10324. doi: 10.1002/ece3.6231. eCollection 2020 Oct.
Fish stocking programs have been implemented to mitigate the blockage of original riverbeds by the construction of hydropower dams, which affects the natural migration of fish populations. However, this method raises concerns regarding the genetic rescue of the original populations of migratory fish species. We investigated the spatial distribution of genetic properties, such as genetic diversity, population structure, and gene flow (migration), of the Neotropical migratory fish in the Três Marias dam in the São Francisco River basin, Brazil, and examined the possible effects of fish stocking programs on populations in this region. In total, 1,017 specimens were sampled from 12 natural sites and a fish stocking program, and genotyped for high-throughput sequencing at 8 microsatellite loci. The populations presented low genetic variability, with evidence of inbreeding and the presence of only four genetic pools; three pools were observed throughout the study region, and the fourth was exclusive to one area in the Paraopeba River. Additionally, we identified high unidirectional gene flow between regions, and a preferred migratory route between the Pará River and the upper portion of the São Francisco River. The fish stocking program succeeded in transposing the genetic pools from downstream to upstream of the Três Marias dam, but, regrettably, promoted genetic homogenization in the upper São Francisco River basin. Moreover, the data show the fragility of this species at the genetic level. This monitoring strategy could be a model for the development of conservation and management measures for migratory fish populations that are consumed by humans.
为减轻水电大坝建设对原始河床的阻塞（这影响了鱼类种群的自然洄游），人们实施了鱼类放流计划。然而，这种方法引发了对洄游鱼类原始种群基因拯救的担忧。我们调查了巴西圣弗朗西斯科河流域特雷斯玛丽亚斯大坝中热带洄游鱼类的遗传特性（如遗传多样性、种群结构和基因流（迁移））的空间分布，并研究了鱼类放流计划对该地区种群可能产生的影响。总共从12个自然地点和一个鱼类放流计划中采集了1017个样本，并对8个微卫星位点进行了高通量测序基因分型。这些种群的遗传变异性较低，存在近亲繁殖的证据，且仅存在四个基因库；在整个研究区域观察到三个基因库，第四个基因库仅存在于帕拉奥佩巴河的一个区域。此外，我们确定了区域之间存在高单向基因流，以及帕拉河和圣弗朗西斯科河上游之间的一条首选洄游路线。鱼类放流计划成功地将基因库从特雷斯玛丽亚斯大坝下游转移到了上游，但遗憾的是，在圣弗朗西斯科河上游流域促进了基因同质化。此外，数据显示了该物种在基因层面的脆弱性。这种监测策略可以作为制定针对被人类食用的洄游鱼类种群的保护和管理措施的一个范例。
