Exotic species, Micropterus salmoides, as a key bioindicator influencing the reservoir health and fish community structure

This study was carried out to analyze the difference in fish fauna, ecological indicator characteristics, biological status of other fish populations, and fish community structures between two groups of reservoir ecosystems along with the invasion of an introduced species, Micropterus salmoides. Six reservoirs were selected and divided into two groups: reservoirs noninvaded and invaded by M. salmoides were RNIv and RIv, respectively. A total of 11,519 individuals of 28 species were sampled in RNIv, whereas 1925 individuals of 19 species were sampled in RIv. Korean endemic fish population dominates in RNIv, exotic fish species, especially M. salmoides, dominate in RIv. Sensitive species dominate in RNIv, whereas tolerant species and carnivore species dominate in RIv. The analysis of total length size distribution showed some difference, particularly in species size group between RNIv and RIv. Also, the analysis of total fish biomass showed a significant difference in accordance with M. salmoides inhabitation. According to the fish community analysis results, as M. salmoides proportion increased, species richness and diversity decreased. Overall data suggest that the dominant distribution of M. salmoides may influence simplification of the fish fauna, species composition, as well as community structure, and affect the length distribution and biomass of other fish population negatively.