Spatial and Temporal Variations in Fish Assemblage in Feitsui Reservoir, in Northern Taiwan, from 2006–2020

Reservoirs are artificial ecosystems that modify the hydrological and environmental components nearby. The long-term monitoring of fish assemblages in reservoirs may provide key information to understand how these allow population fluctuations identify proper conservation strategies. A sentinel-site approach method assessed changes Feitsui Reservoir (1024 ha) over 14 years, including periods 2006–2008, 2010–2011, 2016, 2018, 2020. Fish assemblages, sampled using gill nets, were composed 38 species (12 families 8 orders) with Cyprinidae as dominant family; fauna dominated by family (71%) Cichlidae (20.3%). Principal component analysis nonmetric multidimensional scaling categorized into two groups (cold warm seasons), we identified three parameters significantly correlated season (p < 0.05): SD (R = −0.04), Chl-a 0.01), algal count 0.19); was higher than cold season. assemblage seasons contained no exclusive taxa, contributing dissimilarity between groups. for years before after 2010 indicated partial overlap groups; S. macrops contributed greatly separation (>10% each; SIMPER) O. mossambicus structures 2010. Our findings show importance investigation effects nonnative on native composition.