The spread of invasive fish is a pressing ecological issue that directly and indirectly alters the water quality of lakes. Managers often implement invasive fish suppression programs, but their effects on water quality are rarely examined. Yellowstone Lake provides an opportunity to study how a large-scale suppression program alters nutrient dynamics. Invasive Lake Trout (Salvelinus namaycush) have been removed through gillnetting since 1995 due to their negative effects on native Yellowstone Cutthroat Trout (Oncorhynchus clarkii bouvieri). The carcasses are returned to the depths of Yellowstone Lake, potentially altering nutrient cycling through carcass decomposition. Additionally, the park is exploring the novel use of carcass-analog pellets to induce mortality of Lake Trout embryos, which adds 0.3 mg N/m2 and 0.004 mg P/m2 to one spawning reef. Our objectives are to understand baseline conditions and spatiotemporal patterns in water quality and assess the effects of the carcass-analog pellet treatment. We monitored nitrogen, phosphorus, and several water quality variables biweekly during the open water season from 2023 to 2024 at four locations. We measured nutrient concentrations before and after the pellet treatment at 20 locations, increasing in distance from the treatment site. Our monitoring data indicate that the lake is oligotrophic to mesotrophic (chlorophyll a <9 μg/L). Nutrient and chlorophyll concentrations exhibited seasonal variation with high concentrations after ice-off. The Southeast Arm, which receives the Yellowstone River inflow, exhibited higher chlorophyll concentrations than the other three locations (p< 0.01). The carcass-analog pellet treatment produced minimal effects on water quality surrounding the treatment site and lake-wide. Further monitoring will inform park managers about the effects of carcass-analog pellets and assist their decision-making regarding future application.