Environmental DNA (eDNA) metabarcoding can provide fish-community inventories across river networks. We surveyed ten sites in the Jingdezhen section of the Raohe River system on 20–23 October 2023 and 2–5 June 2024, covering the Donghe River, Chang River, and Le’an River. Three technical process replicates were pooled per site and campaign to produce 20 community profiles. The two surveys detected 96 and 94 taxa, respectively, including 100 fish taxa overall, of which 90 were shared. Richness, Shannon diversity, Simpson diversity, and Pielou evenness did not differ significantly between paired campaigns. Community composition differed between campaigns (Bray–Curtis PERMANOVA: R² = 0.293; Jaccard: R² = 0.185; both adjusted p = 0.002). PERMDISP did not detect unequal dispersion. River-group differentiation was clearer in 2023, whereas neither distance metric was significant in 2024 after multiple-testing correction. A reduced environmental partial RDA accounting for site and campaign effects was not significant (F = 0.971, p = 0.420). These findings provide a two-campaign molecular inventory for the ten surveyed sites and identify between-campaign compositional differences, without demonstrating seasonal dynamics or independent environmental drivers.

Enhancement harvesting and filter-feeding fish stocking are increasingly applied in shallow eutrophic lakes, but their water-quality effects are difficult to evaluate because management signals overlap with seasonal and hydrometeorological variability. We analyzed dense Sentinel-2 observations of Taibo Lake during 2019–2026 using three management stages, phase-specific event windows, and matched forbidden-fishing controls. Regressions adjusted for antecedent precipitation and month used 25 scenes from the 2024 and 2025 events. Chlorophyll-related proxies were descriptively lower during enhancement harvesting than in the 2019 reference year, with no consistent advantage over forbidden fishing. The contrast with 2019 remains confounded by year-specific environmental conditions. Integrated optical and turbidity-related indicators showed no uniform directional change, and representative September scenes revealed substantial within-lake heterogeneity. Event-window comparisons showed no consistent immediate directional response to harvesting or stocking. Exploratory models suggested higher post-stocking normalized difference chlorophyll index (NDCI) values and high-NDCI ratios; only NDCI remained nominally significant after Bonferroni adjustment (adjusted p = 0.036 versus 0.204). Limited event replication and unmodeled temporal dependence precluded confirmatory inference. These findings support phase-specific water-quality monitoring with seasonally matched baselines and continued observation through the post-stocking period to inform adaptive enhancement-fishery management.