Fish indicator species and ecological restoration measures in the Three Gorges Reservoir

The utilization of fish indicator species has emerged as a crucial metric for measuring the health of riverine ecosystems and assessing the efficacy of ecological restoration initiatives. The Three Gorges Dam (TGD), a globally renowned hydraulic engineering marvel, has significantly impacted the environments of the entire Yangtze River. However, few studies have systematically sorted out the indicator species of fish affected by artificial environment and the typical ecological restoration measures in the Three Gorges Reservoir (TGR), a typical riverway reservoir. We summarized the ecological pressures confronting the aquatic ecosystem in the TGR, analyzed how the operation of the dam affected fish and its mechanism, and the evolution of fish dominant species before and after dam construction. This study proposes a list of fish indicator species for the TGR, characterized by degree of endangerment, migratory type, and spawning behavior. Furthermore, it delineates five typical ecological restoration measures—fishing ban, habitat substitution, ecological operation of dams, artificial fish nests, and stocking—implemented to mitigate the impact of the TGD on fish. This study compares the effectiveness of these diverse ecological restoration measures and presents future research prospects. It is suggested that ecological restoration measures based on habitat integrity protection are the most effective. Moreover, we underscore the need for complementary interactions and long-term monitoring among ecological restoration measures to maximize the ecological restoration outcome.