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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 Prochilodus costatus in the Três Marias dam in the São Francisco River basin, Brazil, and examined the possible effects of fish stocking programs on P. costatus 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., We investigated the genetic diversity, population structure, and gene flow (migration) of the Neotropical migratory fish Prochilodus costatus in the Três Marias dam in São Francisco River basin, Brazil. The samples showed low genetic variability, with inbreeding and the presence of only four genetic pools. 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.

Pimelodus maculatus is an important commercial fish found in the São Francisco and Paraná river basins. NGS was used to sequence the mtDNA of P. maculatus. The mtDNA was annotated and aligned with that of 25 other fish species to enable phylogenetic analysis. The complete mtDNA molecule had 16,561 bp and its GC content was 43.7%; the structure was similar to that of other vertebrates: 2 rRNA, 22 tRNA, 13 protein-coding genes, and a D-loop region containing 914 bp. Phylogenetic analysis yielded a tree with a high bootstrap coefficient that was coherent with the actual phylogeny of the species.

Illegal hunting and fishing activities are of great relevance to conservation policies. Few studies with regional focus of the impacts of these activities in Brazil are available. The aim of this study was to characterize illegal hunting and fishing on a national level by collecting data from the environmental police. We analyzed reports prepared by 16 states, all of them which contained a variety of information about seized species, and showed a lack of standardization of data collection and presentation. Illegal fish seizures were predominantly of Amazonian species. Illegal hunting seizures showed the most uniform territorial distribution. Armadillos (Dasypodidae family), pacas (Cuniculus paca), and capybaras (Hydrochoerus hydrochaeris) were the most frequently seized species, and numerous seizures of Brazilian guinea pig (Cavia aperea) were reported in northeastern Brazil. The reports provided by environmental military police have great informative power for conservation policies, but they must be standardized among states to improve the quality of data provided and analysis.