Data for: Visualization of the hidden food sources of bass (Micropterus salmoides), crucian carp (Carassius carassius), and minnow (Zacco platypus) using 18S rRNA V9 primers on urban Singal Reservoir in Korea

Fish are the most important consumers in aquatic ecosystems, and the analysis of fish prey is very important for understanding their short-term feeding characteristics and the connectivity of food webs. In this study, DNA metabarcoding was used to identify the prey of the native fish species, Zacco platypus (the pale chub) and Carassius carassius, and an introduced species, Micropterus salmoides, in domestic lentic ecosystems. Prey community composition, selectivity index, prey diversity, and trophic level analyses were performed. The prey composition ratio analysis showed that in August 2020, 85.8% of M. salmoides' prey was fish from the orders Cypriniformes and Perciformes, and in July 2021, 100% of M. salmoides' prey was zooplankton from the orders Anomopoda and Calanoida. Zooplankton was the main prey of Z. platypus collected in August 2020 (69.5%) and C. carassius collected in July 2021 (88.9%). The selectivity index analysis showed that the preferred prey of M. salmoides was fish from the order Cypriniformes, the preferred prey of Z. platypus was phytoplankton from the division Bacillariophyta, and the preferred prey of C. carassius was zooplankton from the order Cladocera. For the prey width analysis, C. carassius had the highest BI index value (0.8), followed by Z. platypus (0.29), while M. salmoides had BI index values of 0.09, 0.19, and 0.001, indicating low prey width. These results provide fundamental data on the utility of DNA metabarcoding for dietary studies of major fish species in lentic ecosystems and for analyzing food web connectivity based on major prey items.