The Faculty of Fisheries and Marine Sciences, University of Riau reservoir gets water from the butterfly bridge and small ditches. However, in the area around the butterflybridge, manyhumanactivitiesprovide nutrientsto thewaterand asaresult affect the trophic status. To determine the trophic status based on the Trophic Index (TRIX), the study was conducted in February-March 2025. There were 3 s…