PT - JOURNAL ARTICLE AU - Giorgi Dal Pont AU - Camila Duarte Ritter AU - Andre Olivotto Agostinis AU - Paula Valeska Stika AU - Aline Horodesky AU - Nathieli Cozer AU - Eduardo Balsanelli AU - Otto Samuel Mader Netto AU - Caroline Henn AU - Antonio Ostrensky AU - Marcio Roberto Pie TI - Monitoring fish communities through DNA metabarcoding in the fish pass system of the second largest hydropower plant in the world AID - 10.1101/2021.08.17.456687 DP - 2021 Jan 01 TA - bioRxiv PG - 2021.08.17.456687 4099 - http://biorxiv.org/content/early/2021/08/18/2021.08.17.456687.short 4100 - http://biorxiv.org/content/early/2021/08/18/2021.08.17.456687.full AB - The Itaipu Hydroelectric Power Plant is the second largest in the world in power generation. The artificial barrier created by its dam imposes an obstacle for fish migration. Thus, in 2002, a fish pass system, named Piracema Channel, was built to allow fish to access areas upstream of the reservoir. We tested the potential of metabarcoding to monitor the impact of both the dam and associated fish pass system in the Paraná River fish communities and to compare it with traditional monitoring methods. Using a fragment of the 12S gene, we characterized richness and community composition based on amplicon sequence variants, operational taxonomic units, and zero-radius OTUs. We combined GenBank and in-house data for taxonomic assignment. We found that different bioinformatics approaches showed similar results. Also, we found a decrease in fish diversity from 2019 to 2020 probably due to the recent extreme drought experienced in southeastern Brazil. The highest alpha diversity was recorded in the mouth of the fish pass system, located in a protected valley with the highest environmental heterogeneity. Despite the clear indication that the reference databases need to be continuously improved, our results demonstrate the analytical efficiency of the metabarcoding to monitor fish species.Competing Interest StatementThe authors have declared no competing interest.